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2020 Spring Meeting

Nanomaterials and advanced characterization


ALTECH 2020 - analytical techniques for precise characterization of nano materials

Metrology is a prerequisite for the development of novel materials on the nanoscale. It supports the correlation of material properties and functionalities. The expected contributions should demonstrate how innovative analytical techniques enable a deep understanding of new materials. This symposium organized by four major European National Metrology Institutes is a networking platform for scientist and engineers from metrology and research institutes, academia and industry.


Nanomaterials can have unique properties associated with their small dimensionality. Recently functional nanomaterials are rapidly finding wider use in modern technological products in many areas, such as displays, energy conversion, energy storage and sensors. Here, the accurate characterization of nanoscale materials by traceable dimensional and analytical techniques is essential for the development and quality control of innovative products. Metrology for nanoscale materials relies on the ability to measure, with nm or even atomic resolution, in three dimensions over large regions, and traceable to SI units. Often, additional measurands of importance are chemical states and composition. As the structures and the dimensions are ‘nano’ or even at the atomic scale, traditional analytical techniques are being pushed to their limits requiring new innovative approaches to face state of the art problems leading to international standardisation.

This Symposium will cover recent and innovative developments in analytical techniques that can provide precise characterization of materials and devices with nanoscale and/or atomic resolution. The objective of this symposium is both to highlight the capabilities of precise techniques for the determination of the key structural and material parameters and for a better understanding of the functional properties of challenging new materials. One major focus will be on application of these techniques to new and complex materials systems with high potential of industrial application which includes nanoscale objects (nanowires, quantum dots, nanoparticles) and nanostructured thin films of organic, hydrid or inorganic semicondutors, functionalized surfaces and others.

A huge range of measurement tools have emerged to characterize nanomaterials from different perspectives. To this end, this symposium will have a special focus on in-situ, operando and complementary metrology that seeks to merge the best attributes of different measurement perspectives to support each other for solving analytical problems. Complementary analytical techniques are crucial for the analysis of complex materials, where often a single measurement method is not sufficient to ensure metrological precision, traceability and a well-described uncertainty budget. Often, a combination of optical methods, X-ray methods, ion beam methods, surface analytical and scanning-probe methods is required to ensure accurate results. Lastly, for advanced material based devices, nanoscale probing of optical and electronic properties is crucial, using methods such as tip-enhanced spectroscopy, super-resolution microscopy and other advanced opto-electronic, charged particle based and x-ray based characterization techniques. As many of these techniques depend on modeling for gaining results, effective material analysis and computational optical analysis of materials and thin layers will be a central subject.

Hot topics to be covered by the symposium:

  • Combined metrology for complex thin films and nanomaterials (e.g. new multiple-method approaches and combined data analysis) Analytical and dimensional nanometrology including combined methods addressing thin films, interfaces, advanced materials and nanostructures, qualification of calibration specimen and international standardization.
  • X-Ray diffraction, tomography, scattering and spectrometry-based applications on advanced materials and in nanoscience
  • Ion beam and charged particle techniques (SIMS, XPS, …) for characterization of nanomaterials
  • Advanced optical spectroscopic techniques, ultramicroscopy and interferometric or non-interferometric methods
  • Scanning-probe techniques for high resolution characterization of organic, hybrid and inorganic advanced materials (AFM, tip-enhanced spectroscopy …)
  • Advanced metrology for energy conversion and storage materials (CIGS, thin film photovoltaics, batteries, fuel cells) as well as for nanoelectronics with respect to thin layer, depth profiling, interfacial elemental, coordination and species information
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09:00 Opening Welcome - ALTECH chairs    
Hybrid characterisation methods I : Burkhard Beckhoff and Marie-Christine Lépy
Authors : J-P Barnes, E. Langer, M. Moreno, Y. Mazel, E. Nolot, O. Renault, N. Chevalier, T. Maindron, B. Gautier, A. Tempez, S. Legendre.
Affiliations : Univ. Grenoble Alpes, CEA, LETI, F-38000 Grenoble; Univ. Grenoble Alpes, CEA, LETI, F-38000 Grenoble; Univ. Grenoble Alpes, CEA, LETI, F-38000 Grenoble; Univ. Grenoble Alpes, CEA, LETI, F-38000 Grenoble; Univ. Grenoble Alpes, CEA, LETI, F-38000 Grenoble; Univ. Grenoble Alpes, CEA, LETI, F-38000 Grenoble; Univ. Grenoble Alpes, CEA, LETI, F-38000 Grenoble; Univ. Grenoble Alpes, CEA, LETI, F-38000 Grenoble; Université de Lyon, INSA Lyon, Institut des Nanotechnologies de Lyon, UMR CNRS 5270, F- 69621 Villeurbanne cedex, France; HORIBA FRANCE S.A.S., Avenue de la Vauve - Passage Jobin Yvon, CS 45002 - 91120 Palaiseau – France; HORIBA FRANCE S.A.S., Avenue de la Vauve - Passage Jobin Yvon, CS 45002 - 91120 Palaiseau – France.

Resume : The increasingly complex structures and large variety of materials used in modern nano and opto-electronic devices brings many challenges for their characterization. To answer certain analytical questions it is necessary to combine several techniques to get reliable information and to combine different types of information on the same sample. For organic samples the issue of beam damage is critical, especially when ageing of devices needs to be investigated such as with organic light emitting diodes. For inorganic samples there is often a need to give fast feedback to remain competitive for the development of new technology and the new processes and materials that are involved. Examples of how plasma profiling time-of-flight mass spectrometry (PP-TOFMS) can provide fast feedback as a complement to SIMS analysis will be given. This presentation will address developments in SIMS analysis for applications from semiconductor technology to display technology and the importance of using several techniques such as scanning probe microscopy, X-ray tomography, XPS. The importance of sample preparation to enable multi-technique studies will be discussed and approaches such as focused ion beam milling, wedge crater preparation and transfer between instruments under a protected environment (vacuum or inert gas) will be addressed.

Authors : G. Sarau1,2,3, L. Kling3, F. Vollnhals3,4, L. Mill3,5, B. E. Oßmann2,6,7, and S. Christiansen1,2,3,4,8
Affiliations : 1. Fraunhofer Institute for Ceramic Technologies and Systems (IKTS), Winterbergstr. 28, 01277 Dresden, Germany; 2. Max Planck Institute for the Science of Light, Staudtstr. 2, 91058 Erlangen, Germany; 3. Institute for Nanotechnology and Correlative Microscopy eV (INAM), Äußere Nürnbergerstr. 62, 91301 Forchheim, Germany; 4. Institute of Optics, Information and Photonics, Friedrich-Alexander University Erlangen-Nürnberg, Staudtstr. 7/B2, 91058 Erlangen, Germany; 5. Pattern Recognition Lab, Friedrich-Alexander University Erlangen-Nürnberg, Martensstr. 3, 91058 Erlangen, Germany; 6. Bavarian Health and Food Safety Authority, Eggenreuther Weg 43, 91058 Erlangen, Germany; 7. Food Chemistry Unit, Department of Chemistry and Pharmacy - Emil Fischer Center, Friedrich-Alexander University Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058 Erlangen, Germany; 8. Physics Department, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany

Resume : Detection and extensive analysis of plastic micro- and nanomaterials (< 1.5 µm) are important to correctly assess toxicological healthy risks for humans. Here, we show the successive characterization of the same micro- and nanoplastic objects (standards, environmental, in tissues) using high-resolution complementary analytical techniques. Two precise relocalization approaches were demonstrated involving either a combined SEM-Raman instrument or independent instruments (SEM, HIM, micro-Raman, TERS) by means of a position encoder tag. In the first case, the stage with the sample is moved between the SEM and Raman positions within the same SEM chamber. In the second case, a so-called nanoGPS tag attached directly to the sample or sample holder is used to translate the sample coordinates corresponding to the regions of interest to the stage coordinates of different instruments regardless of the sample orientation. It was found that low-voltage SEM/HIM provide detailed surface imaging of single and agglomerated micro- and nanoplastics including size, texture, cracks, geometry, adhered pigments, biofilms, and other hazardous chemicals. Micro-Raman and TERS measurements on identical objects enabled usually their chemical identification, the latter down to nanoscale (~ 30 nm). These workflows are developed to account for statistically relevant monitoring of small-sized plastics towards reliable metrology and standardisation, being further supported by machine learning algorithms.

10:00 Coffee Break    
Hybrid characterisation methods II : Burkhard Beckhoff and Marie-Christine Lépy
Authors : Andrea Falqui, Elisa Sogne, Giorgio Pia, Francesco Delogu, Federico Scaglione, Paola Rizzi.
Affiliations : King Abdullah University of Science and Technology (KAUST), BESE Division, NABLA Lab, Thuwal, Saudi Arabia; University of Cagliari, Department of Mechanical, Chemical and Materials Engineering, Cagliari, Italy; University of Turin, Department of Chemistry, Turin, Italy.

Resume : Nanoporous gold (NPG) has gained increasing interest for applications such as catalysis, energy storage and surface-enhanced Raman scattering. Most of these applications require that NPG works within specific thermal range, often giving rise to a coarsening dynamics that change the NPG features and related properties over time. Thus, aiming at understanding how NPG evolves during such a thermal coarsening, we studied it by a novel SEM-based approach and related modelling. First, we imaged the nanoligaments constituting an NPG thin film and how they change over time upon isothermal annealing at different temperature by in situ environmental scanning electron microscopy (in situ ESEM). This allowed studying the ligament growth kinetics and the corresponding activation energy. Second, the whole 3D structure of NPG film, both not annealed and annealed by in situ ESEM at different temperature, was cut via focused ion beam, thus allowing to image the samples volume throughout the whole film thickness. The following 3D-reconstruction indicated that during the isothermal annealing gold formed large crystal domains with diverse orientation and the NPG film porosity always decreased all over its entire volume, being this decrease depending on the annealing temperature. Moreover, the coarsening looked more pronounced in the zones closer to the film’s two external surfaces for any annealing temperature. All observed phenomena were modelled to describe the mechanisms ruling them.

Authors : K. Paraskevoudis, T. Efthymiadis, S. Bei, E. P. Koumoulos
Affiliations : Innovation in Research & Engineering Solutions (IRES), Boulevard Edmond Machtens 79/22, 1080 Brussels, Belgium,

Resume : This work describes a novel methodology of data documentation in materials characterisation, which has as starting point the creation and usage of any Data Management Plan (DMP) for scientific data in the field of materials science and engineering, followed by the development and exploitation of ontologies for the harnessing of data created through experimental techniques. The case study that is discussed here is nanoindentation, a widely used method for the experimental assessment of mechanical properties on a small scale. Except for technology development and synthesis of new materials and hybrid composite structures, the need of developing new evaluation methodologies is highlighted to assist and accelerate developments. Artificial Intelligence (AI) is a promising candidate to bridge the gap between Research and Development (R&D) and industry by establishing unbiased relations between microstructure and properties. This is majorly appreciated in case of Safe-by-Design requirements regarding mechanical performance, and real-time characterisation. Being representative, k-means, Random Forrest (RF), Support Vector Machines (SVM), k-Nearest Neighbors (KNN) are common Machine Learning (ML) algorithms used in multiclass classification problems for automated classification of microstructures. This work contributes to nanocomposites design and quality control associated with identifying the optimum inclusion in nanomaterials reinforcement by microstructure assessment. In this direction, Artificial Intelligence can provide a module for enabling fast, in-line, and real-time metrological characterisation of nanoindentation data. This work has been partially supported by the EU Horizon 2020 Programmes: MODCOMP (GA No 685844), SMARTFAN (GA No 760779), OYSTER (GA No 760827) and REPAIR3D (GA No 814588).

Authors : Loïc CROUZIER, Alexandra DELVALLEE, Laurent DEVOILLE, Sébastien DUCOURTIEUX, Christophe TROMAS, Nicolas FELTIN
Affiliations : Laboratoire National de métrologie et d’Essais – Nanometrology (France); Laboratoire National de métrologie et d’Essais – Nanometrology (France); Laboratoire National de métrologie et d’Essais – Nanometrology (France);Laboratoire National de métrologie et d’Essais – Nanometrology (France); Institut Pprime Département Physique et Mécanique des Matériaux (France); Laboratoire National de métrologie et d’Essais – Nanometrology (France)

Resume : So far, there is no instrument capable of measuring a nanoparticle in the three directions of space with controlled uncertainty. The combination of several instruments is therefore necessary to metrologically characterize the dimensional properties of a nano-object. This study proposes a new approach to take advantage of the complementarity of AFM (Atomic Force Microscopy) and SEM (Scanning Electron Microscopy) techniques for the 3D measurement of the dimensional parameters of nanoparticles (NP). Indeed, the SEM gives no quantitative information along the Z axis, whereas the uncertainty associated with the AFM measurement of nanoparticles is close to 1.5 nm. Conversely, measurements along the X and Y axes are impacted by the tip/NP convolution for AFM when it is possible to measure the lateral diameter of a population of nanoparticles by SEM with an uncertainty of a few nm. The use of the new P900H60 calibration standard, of which mean array pitch and step height are measured via LNE's metrological AFM, ensures the traceability of both instruments to the SI meter. A comparison between SEM (area equivalent and Feret diameters) and AFM (height) measurements was performed on supposedly spherical silica NPs. Although their spherical nature imposes equality between the different measurements, a systematic discrepancy is observed for the smallest particles with measured diameter greater than height. The study of the sphericity of the silica particles leads to the hypothesis that the shape of silica NP is ellipsoidal and the orientation of the NP on the substrate has an impact on the observed discrepancies.

Authors : Yongmin Kim
Affiliations : KIST, Stanford

Resume : Observation of Interaction between Platinum and Metal Oxide Supports Prepared by Atomic Layer Deposition

Authors : Oana Cojocaru-Mirédin(1), Henning Hollermann(1), Nikita Polin(1), Alexander Meledin(2), and Matthias Wuttig(1,3)
Affiliations : (1)I. Institute of Physics (IA), RWTH Aachen University, 52074 Aachen, Germany (2) GFE RWTH Aachen, Mies-van-der-Rohe-Straße 59, 52074 Aachen (3)JARA-FIT Institute Green-IT, RWTH Aachen University and Forschungszentrum Jülich, 52056 Aachen, Germany

Resume : Interfacial Phase Change Materials (IPCM) based on chalcogenide superlattices (CSL) are promising candidates for non-volatile random-access memory devices. They exhibit improved properties compared to its bulk analogues, such as multi-level switching, faster switching time, and reduced thermal conductivity. However, their precise local composition at the nanometer scale remains the missing piece in the material design puzzle. In the present work, correlative atom probe tomography-transmission electron microscopy studies were conducted for the first time to quantify the intermixing between GeTe/SnTe and Sb2Te3 in highly-textured crystalline superlattices. These studies clearly proved the presence of Sb in GeTe/SnTe, but also of Ge/Sn in Sb2Te3. Moreover, a much stronger intermixing takes place at the grain boundaries, where the intermixing degree is strongly dependent on the disorientation angle; i.e. Ge2Sb2Te5 metastable phase nucleates at the boundary with a disorientation angle of 34°. Finally, the impact of the chemical intermixing on the physical properties of IPCM will be discussed.

12:00 Lunch break    
Advanced scanning probe microscopy and nanomaterials : Andreas Hertwig and Natascia De Leo
Authors : Sebastian Wood, Filipe Richheimer, Ruth Rawcliffe, Tomas Peach, Maxim Shkunov, and Fernando Castro
Affiliations : National Physical Laboratory, Teddington, Middlesex, UK; National Physical Laboratory, Teddington, Middlesex, UK; Advanced Technology Institute, Faculty of Engineering & Physical Sciences, University of Surrey, Guildford, UK; Advanced Technology Institute, Faculty of Engineering & Physical Sciences, University of Surrey, Guildford, UK; Advanced Technology Institute, Faculty of Engineering & Physical Sciences, University of Surrey, Guildford, UK; National Physical Laboratory, Teddington, Middlesex, UK

Resume : Nano-scale materials are important for a wide range of applications, including optical and electronic devices, whose functional performance properties are critically dependent on the nano-structure. However, detailed characterisation of structure-function relationships at the nano-scale presents a metrological challenge due to the small dimensions involved. In particular, the need for reliable, quantitative characterisation presents a barrier to successful commercialization of nanoelectronics devices. We consider the use of optical spectroscopy (confocal and near-field) as well as electrical modes of scanning probe microscopy (C-AFM) for characterisation of organic, inorganic, and hybrid nanomaterials. These techniques are sensitive to chemical and optoelectronic properties enabling direct access to structure-function relationships, but cannot be considered fully quantitative due to the lack reference samples and methods to enable traceability to the International System of Units (SI). Here we propose and demonstrate a suitable sample based on aligned semiconducting nanowires, which provide a linear feature roughly 10 nm wide with strong electrical and spectroscopic contrast that can be easily and uniquely identified. We present findings from a pre-normative inter-laboratory study testing the suitability of these samples and the associated measurement protocol.

Authors : Amelie Axt1,2, and Stefan A.L. Weber1,2
Affiliations : 1Max-Planck-Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany. 2Institute of Physics, Johannes Gutenberg University Mainz, 55099 Mainz, Germany.

Resume : KPFM is widely used to map the nanoscale potential distribution in operating devices, e.g. in thin film transistors, battery materials and solar cells. Quantitative surface potential measurements are crucial for understanding the operation principles of functional nanostructures in these electronic devices. Nevertheless, KPFM is prone to certain imaging artifacts, such as crosstalk from topography or stray electric fields. We compare different amplitude modulation (AM) and frequency modulation (FM) KPFM detection methods on a reference structure consisting of a glass-platinum interdigitated electrode array. This structure allows to modify the surface potential externally and minimizes corrosion, while mimicking the sample geometry in device measurements. In particular, we investigate how quantitative different KPFM methods can measure a predefined externally applied voltage difference between the electrodes. We found that when operated with a feedback, FM KPFM methods provide more quantitative results that are less affected by the presence of stray electric fields compared to AM KPFM methods [1]. Reference: [1] Axt, A., Hermes, I. M., Bergmann, V. W., Tausendpfund, N. & Weber, S. A. L. Know your full potential: Quantitative Kelvin probe force microscopy on nanoscale electrical devices. Beilstein J. Nanotechnol. 9, 1809–1919 (2018).

Authors : Petr Klapetek, Andrew Yacoot, Marek Havlíček, Jan Martinek
Affiliations : Czech Metrology Institute, Okruzni 31, 638 00 Brno, Czech Republic; National Physical Laboratory, Hampton Rd, Teddington TW11 0LW, United Kingdom

Resume : Many of the Scanning Probe Microscopy methods are based on the probe-sample contact formed under load. Mechanical contact is used in all the nano-mechanical scanning regimes to determine the local mechanical properties of the sample. It is also used in heat or electron transport based methods, like Scanning Thermal Microscopy or Conductive Atomic Force Microscopy. Different variants of these methods and/or their combinations are available in commercial instruments, however, treatment of the contact formation and evolution is still one of the most problematic uncertainty components when such measurements are being made in a quantitative way. In this contribution the aspects of probe-sample elastic deformation in different Scanning Probe Microscopy configurations will be studied both experimentally, using a microscope combined with traceable length and force sensors, and numerically, using Finite Element method and a fast mass-spring model implemented on a graphics card. The uncertainties related to the probe-sample contact formation will be evaluated and a guidance for their estimation from measured data will be given.

Authors : Marco Coïsson 1, Wilhelm Hüttenes 2, Matteo Cialone 3, Gabriele Barrera 1, Federica Celegato 1, Paola Rizzi 3, Zoe Barber 2, Paola Tiberto 1
Affiliations : 1 INRIM, Advanced Materials and Life Sciences Division, Torino, Italy; 2 Cambridge University, UK; 3 University of Torino, Italy

Resume : Magnetostriction is an intrinsic property of ferromagnetic materials whose overall dimensions change when an external magnetic field is applied. When scaling down towards the nanoscale, the reduced dimensionality introduces several challenges for the direct measurement of the magnetostriction, since the change in dimensions is in the nanometer scale. In order to measure magnetostriction of thin films, these are often mechanically coupled to a non-magnetic substrate, making a flexible bimorph. However, either custom cantilevers or measurement setups are usually required. In this work, we present a method based on standard atomic force microscopy cantilevers coated with Fe81Al19 films of different thickness. A commercial atomic force microscope (AFM) operating under a variable magnetic field is exploited to measure the vertical deflection of the bimorph induced by the magnetostrictive coating. The microscope is operated in fixed-point contact mode on a flat Si sample. The interplay between the magnetostrictive force, bending the cantilever up when the magnetic field is applied, and the tip-sample interaction, letting the AFM compensate for the magnetically induced upward deflection, allows the measurement of the vertical displacement of the cantilever, as a function of the applied magnetic field. Through the measurement of the deflection of bimorphs with different coating thickness, the magnetostriction constant of the alloy can be determined with a suitable model.

Authors : Matěj Hývl (1), Gizem Nogay (2), Philipp Loper (3), Franz-Josef Haug (3), Quentin Jeangros (3), Antonín Fejfar (1), Christophe Ballif (2,3), Martin Ledinský (1)
Affiliations : (1) Institute of Physics, Academy of Sciences of the Czech Republic, Cukrovarnická 10, 162 00 Prague 6, Czech Republic (2) PV-Center, Centre Suisse d’Électronique et de Microtechnique, Rue Jaquet-Droz 1, CH-2002 Neuchâtel, Switzerland (3) Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Microengineering (IMT), Photovoltaics and Thin-Film Electronics Laboratory (PV-Lab), Rue de la Maladière 71b, 2000 Neuchâtel, Switzerland

Resume : Hole-selective passivating contacts are used as an effective strategy to decrease recombination losses in c-Si solar cells. Our research deals with high thermal budget contacts: thin silicon oxide (SiOx) and a boron-doped Si-rich SiCx layers on Si wafer are annealed at temperatures above 750°C. During annealing, thin SiOx layer may disrupt, while SiCx layer partially crystallizes. Optimal performance of the contact is achieved with annealing temperature around 850°C [1]. To explore the transport mechanism through the contact we performed a series of C-AFM tomography [2] measurements. 3D current map of the sample layers can be constructed from consecutive scans with large force applied to the AFM tip, removing the material during the measurement. This enables us to directly visualize the 3D reconstruction of the charge carrier transport through the selective contact. C-AFM tomography reveals conductive channels spanning vertically through the sample starting from interfacial SiOx going up to the sample surface. We report that the density of these conductive channels is not affected by the SiOx thickness, but rather by the annealing temperature and the SiCx layer crystallinity. Visualisation of the charge carrier transport paths offers the direct explanation of the optimal performance of the contact annealed at 850°C – oxide layer remains sufficiently compact to passivate the Si wafer, while the crystalline conductive paths in SiCx layer act as the local electrical contacts. [1] G. Nogay et al., ‘Crystalline Silicon Solar Cells With Coannealed Electron- and Hole-Selective SiCxPassivating Contacts’, IEEE Journal of Photovoltaics, vol. 8, no. 6, pp. 1478–1485, Nov. 2018, doi: 10.1109/JPHOTOV.2018.2866189. [2] U. Celano et al., ‘Conductive-AFM tomography for 3D filament observation in resistive switching devices’, in 2013 IEEE International Electron Devices Meeting, 2013, pp. 21.6.1-21.6.4, doi: 10.1109/IEDM.2013.6724679.

Authors : Paul Markus [1], Daniel E. Martínez-Tong [2,3], Beatriz Robles-Hernández [2,3], Michelina Soccio [4], Giulia Guidotti [4], Nadia Lotti [4], Georg Papastavrou [1], Angel Alegria [2,3]
Affiliations : [1] Physical Chemistry II. Faculty of Biology. University of Bayreuth. Universitätsstraße 30, 95440 Bayreuth – Germany. [2] Departamento de Física de Materiales, Basque Country University (UPV/EHU). P. Manuel de Lardizábal 3, E-20018 San Sebastián – Spain. [3] Centro de Física de Materiales (CSIC – UPV/EHU). P. Manuel Lardizábal 5, E-20018 San Sebastián – Spain. [4] Civil, Chemical, Environmental and Materials Engineering Dept., University of Bologna, Via Terracini 28, 40131, Bologna, Italy

Resume : The study of dynamic processes in polymers and soft matter systems provides a deep insight into the different role of the molecular constituents into the final materials’ properties. Broadband dielectric spectroscopy (BDS) is among the best-established experimental techniques suitable for such studies. This technique allows probing the dipole reorientations and/or charge motions dislocations taking place inside the sample, when an external electrical AC-field is applied. However, BDS lacks spatial resolution, as many macroscopic techniques. To overcome this issue, we have developed during the past years AFM-based methods to perform local BDS measurements allowing for a lateral resolution < 100 nm. Our approach allows for direct access to the frequency-dependent dielectric permittivity of insulating thin films. Here, we present our recent advances in probing the molecular dynamics of polymer thin films by local dielectric spectroscopy. In particular, we investigated films of novel, bio-based polymer blends. Different thermal treatments allowed obtaining samples with distinct structures, as inferred from the surface features, as nanocrystals. We probed the molecular relaxations at different zones of the films. This approach allowed testing the potential miscibility of the components in these blends; a fact not directly evidenced by topographical and mechanical imaging alone, and which is of outmost important for possible applications of these materials.

Authors : Filipe Richheimer* (1,2); Alessandro Catanzaro (1); Sebastian Wood (1); Mark Baker (2); Robert A. Dorey (2); Olga Kazakova (1) and Fernando A. Castro (1)
Affiliations : (1)National Physical Laboratory, UK (2)University of Surrey, UK * lead presenter

Resume : Multimodal Scanning Force Microscopy (SFM) is a valuable family of techniques for characterisation of nanomaterials, where complementary sensitivities to physical properties of different modes are combined to separate species within a scan. Here we apply a combination of conductive and Kelvin probe electrical modes to a Van der Waals heterostructure sample. By combining the measurement datasets and applying cluster analysis we are able to reliably distinguish different heterostructure species within the sample, as well as providing larger datasets for improved statistical significance in metrological applications of multimodal microscopy. We study the effect of contact engineering by adding a graphene buffer layer to a vertical metal-TMD contact. Multimodal SFM techniques are employed in a combinatorial manner to locally study the influence of a graphene buffer layer on the contact resistance, compared to neighboring regions without graphene.

Authors : Qian Yang, Andre Geim
Affiliations : School of Physics and Astronomy, University of Manchester, Manchester M13 9PL, UK; National Graphene Institute, University of Manchester, Manchester M13 9PL, UK

Resume : Isolated atomic planes (two-dimensional materials) can be reassembled into designer structures made layer by layer in a precisely chosen sequence. This is usually referred to as van der Waals heterostructures. Recently, our group has reported that using such van der Waals (vdW) assembly not only heterostructures but also two-dimensional voids (2D voids) could be created [1-2]. The latter can be viewed as if individual atomic planes were pulled out of a bulk crystal leaving an atomically-thin void behind (Fig. 1). This technology offers the smallest possible empty spaces that can vary from just a few angstroms in height up to many nanometres, if required. On this basis, we investigated the mass transport under such strong confinement, including how ions and water transport differently inside such angstrom-scale slits, how does confinement affect the dielectric properties of water, and how does capillary condensation happen at the real atomic scale, etc. With these knowledge, we are aiming to search for new phenomena and better fundamental understanding.

16:00 Coffee Break    
Nanoscale characterisation and nanomaterials : Sebastian Risse and Thomas Hase
Authors : Christoph Hörenz, Ulrich Mansfeld, Francesco Pellegrino, Valter Maurino, Sylvie Marguet, Fabienne Testard, Olivier Taché, Dorota Bartczak, Susana Nunez, Isabel Abad Alvaro, Heidi Goenaga-Infante, Vasile-Dan Hodoroaba
Affiliations : Federal Institute for Materials Research and Testing (BAM), 12205 Berlin, Germany; Dipartimento di Chimica and Centro Interdipartimentale NIS, Università di Torino, 10125 Turin, Italy; Nimbe, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CNRS, 91191 Gif Sur Yvette, France; National Measurement Laboratory (NML), Queens Road, Teddington, Middlesex, TW11 0LY, UK

Resume : By far most of the current nanoparticle (NP) research is dealing with (quasi-) spherical and/or monodisperse particles. However, many NPs used in industrial applications are rather aspherical and polydisperse. This inhomogeneity considerably hampers their characterization and, particularly, the accurate determination of the nanoparticle size. In order to overcome this problem and to promote the availability of standardized size measurement methods, it is crucial to develop and establish (candidate) reference materials with inhomogeneous size (distribution), aspherical shape as well as agglomerated or aggregated particles. Therefore, a new set of NPs including Au-, SiO2 , and TiO2-particles is investigated. The range of properties comprises polydisperse spherical, bimodal spherical, rod-like, acicular, bipyramidal, sheet-like as well as cubic NPs. With respect to a good traceability of the measurements, size and size distributions of the candidate reference materials are determined using microscopic methods like scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning electron microscopy in transmission mode (STEM-in-SEM), atomic force microscopy (AFM) as well as small angle X-ray scattering (SAXS) as an ensemble technique. The development of protocols for sample preparation are of particular importance to obtain a homogeneous dispersion of the NPs on a substrate. Further, approaches for signal modelling for all the methods above are being developed.

Authors : Fabian Kraft, Kimmo Mustonen, Morris Weimerskirch, Tristan Nagy, Toma Susi
Affiliations : Physics of Nanostructured Materials University of Vienna, Physics of Nanostructured Materials University of Vienna, Physics of Nanostructured Materials University of Vienna, Department of Physical Chemistry University of Vienna, Physics of Nanostructured Materials University of Vienna,

Resume : For high-resolution electron microscopy of 2D materials, it is vital to have atomically clean sample surfaces. Established cleaning methods such as ex-situ heat treatments often leave a layer of contamination on the surface and can also cause damage. So-called pre-situ methods were recently developed for cleaning samples using radiative or laser heating in the same vacuum system as an aberration-corrected scanning transmission electron microscope (STEM), causing less damage and producing cleaner surfaces [1]. To further enhance the laser cleaning of graphene and other 2D materials, we have developed a far-field laser system with focusing optics for irradiating a sample in-situ while it is observed with STEM. In addition to enabling finer control over the cleaning process, laser irradiation activates photon-induced electron energy loss and gain processes that may be spectroscopically accessed to study plasmons and other electronic properties [2]. [1] Tripathi, M. et al. Cleaning graphene: Comparing heat treatments in air and in vacuum. physica status solidi (RRL) – Rapid Research Letters 11, 1700124 (2017). [2] Das, P. et al. Stimulated electron energy loss and gain in an electron microscope without a pulsed electron gun. Ultramicroscopy 203, 44–51 (2019).

Authors : Alberto Casu, Danilo Loche, Andrea Falqui
Affiliations : NABLA Lab, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology - Thuwal, Saudi Arabia

Resume : Amorphous sub-micron and nano-sized iron particles are drawing a growing interest as a possible alternative to single or polycrystalline structures, due to the variation in physical properties caused by the absence of a crystal structure. Then, studying the amorphous-to-crystal transition represents a necessary step to assess the limits between these two states and the variations of physical properties across these borders. We prepared by chemical reduction of Fe3+ ions using NaBH4 amorphous iron particles with sizes ranging between 80 and 200 nm and showing a high stability against oxidation and investigated their crystallization by differential scanning calorimetry (DSC), X-ray diffraction (XRD), and in situ heating transmission electron microscopy (TEM). In situ TEM was performed by combining electron diffraction of a selected sample area with bright and dark field TEM imaging, to determine that the temperature-induced crystallization turns the starting amorphous particles into polycrystalline alpha-Fe ones. This result, obtained under the high vacuum of the TEM column, is shifted in temperature, going to 823 K from the 738 K previously observed by DSC and XRD under 105 Pa of Ar. This variation indicates the pivotal role of the external pressure in influencing the starting point of crystallization. Conversely, further heating triggers the growth in size of the crystal domains upon both pressure conditions, even if with some pressure-related differences.

Authors : Wen-Shan Zhang (a), Maik Matthiesen (b), Jana Zaumseil (b), Lutz Gade (c), Rasmus R. Schröder (a,d)
Affiliations : (a) Centre for Advanced Materials (CAM), Ruprecht-Karls-Universität Heidelberg, Germany; (b) Institute of Physical Chemistry, Ruprecht-Karls-Universität Heidelberg, Germany; (c) Institute of Inorganic Chemistry, Ruprecht-Karls-Universität Heidelberg, Germany; (d) Cryo Electron Microscopy, BioQuant, Heidelberg University Hospital, Germany.

Resume : Film quality is a key parameter for solution-processed organic thin film transistors (OTFTs). When measuring charge carrier mobility using OTFTs, one would therefore like to eliminate effects of morphological inhomogeneity. In this contribution, we demonstrate a novel method to characterize the organic thin film, to visualize its morphological defects and thus, to correct the charge carrier mobility. The main tool we employ is a prototype scanning electron microscope (SEM), which provides an ultra-low energy beam, down to a landing energy of 10 eV. The unique design of an added energy-filtering detector enables to record the energy spectrum of secondary electrons (SE) emitted from the materials studied. To characterize the transistor thin film, we first recorded SE spectra of the thin film by screening the beam energy from 20 eV to 1000 eV. Two critical energy points E1 and E2 were found. When the beam energy lies between E1 and E2, the thin film is positively charged; otherwise, it is negatively charged. Due to the semiconducting character of the thin film, the in situ generated charge can dissipate if the site is well connected to source/drain. Defects, including cracks, islands, narrow paths, will stay charged and can consequently be distinguished from the non-charging areas by their SE image contrast. The whole channel between source and drain was imaged under a positive charging condition. Post-processing of the images identifies the defects, which then allows to calculate an effective channel width, which is then used to correct charge carrier mobility.

Authors : Bruno Torre, Andrea Giugni, Marco Allione, Monica Marini, Xinyu Zhang, Enzo Di Fabrizio
Affiliations : King Abdullah University of Science and Technology, Kingdom of Saudi Arabia, Thuwal, 23955-6900

Resume : Hot Electron Nanonscopy and spectroscopy (HENs) is a recently developed technique relying on the unbiased emission of energetic electrons at a Schottky junction after plasmon decay, once excited by an impinging laser excitation. A key element is the design and realization of micro/nano-strucured AFM probes to efficiently convert impinging photons into Surface Plasmon Polaritons [1], to guide them to the apex of an AFM tip and promote their decay into energized electrons and photons [2]. The tradeoff between fabrication complexity and the final efficiency is explored for different designs [3]. In recent years, we employed this technique with an AFM based architecture to exploit the nanometric spatial resolution and controlled interaction on several inorganic semiconductors, proofing an extremely high efficiency in hot-carriers generation and high spatial resolution [4]. More recently, we have proved this technique capable to detect and image edge states in 2D MoS2, not visible to other electrical AFM modes [3]. Lately we developed the first application to p-doped organic semiconductor, broadening the range of applicability to a new class of materials where conductance is dominated by holes. At the same time these studies pave the way to the possibility to study hot-carriers conduction under controlled strain and deformation, and the influence of morphology on conductance. For this reason, we have coupled a Raman detection channel to the plasmon photonic decay channel at the tip to provide structural information aside of the conductive/spectroscopic one. References [1] A. Giugni, B. Torre, M. Allione, G. Perozziello, P. Candeloro, and E. Di Fabrizio “Hot Electron Nanoscopy and Spectroscopy (HENs): Applications in Nanomaterials”, DOI: 10.1002/9783527699773.ch15, In book: Conductive Atomic Force Microscopy, pp.319-354 [2] Mark Stockman, “Nanofocusing of Optical Energy in Tapered Plasmonic Waveguides”, PRL, Vol.93, 137404, (2004) [3] A.Giugni, B. Torre, M. Allione, G. Das, Z. Wang, X. He, H. N. Alshareef, E. Di Fabrizio, “Experimental Route to Scanning Probe Hot‐Electron Nanoscopy (HENs) Applied to 2D Material”Advanced Optical Materials 2017, 5, 1700195. [4] A. Giugni, B. Torre, A. Toma, M. Francardi, M. Malerba, A. Alabastri, R. Proietti Zaccaria, M. I. Stockman& E. Di Fabrizio, “Hot-electron nanoscopy using adiabatic compression of surface plasmons”, Nature Nanotechnology, volume8, pages845–852 (2013)

Authors : Yi-Hsuan Lin, Ming-Yen Lu
Affiliations : Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 300, Taiwan

Resume : ZnO-based nanostructures are widely used in the applications on light-emitting diodes, piezoelectric devices and gas sensors, due to their excellent and multifunctional properties. In this study, we conducted experiments to understand the solid-state diffusion behavior of Ni in ZnO nanowire (NW) with in-situ technique in transmission electron microscopy (TEM). Firstly, ZnO NWs were grown by chemical vaper deposition (CVD) and then transferred to silicon nitride membrane for in situ observation. We successfully fabricated Ni/ZnO NW device after the lithography process and the Ni deposition. Then, the device was heated up to 873 K in TEM. The in-situ TEM analyses reveal a complete replacement of ZnO NW by Ni with sharp interface along [001]-ZnO as time increases. Also, from the scanning TEM (STEM) images, the interface of the heterostructure shows an epitaxial relationship of (1-11) Ni // (001) ZnO and [112] Ni // [-110] ZnO. The diffusion distances of Ni display a linear behavior with time at various temperature implies the rate limiting step of the diffusion is reaction control. Moreover, the activation energy can be estimated to be 202.05 kJ/mol. We believed that our findings can provide the understanding for the reaction at metal-semiconductor interface and the processing techniques in nanotechnology.

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08:45 Plenary Session 1    
Advances in optical characterisation : Omar El Gawhary and Sebastian Wood
Authors : Emiliano Descrovi
Affiliations : Politecnico di Torino

Resume : Historically, optical imaging formation relies on the possibility of collecting light scattered/diffracted by an object to reconstruct an intensity distribution able to provide information about the object spatial distribution. This holds particularly for objects exhibiting a refractive index very close to that one of the external environment, such as cells or thin slabs of organic tissues. In an attempt to increase the image contrast, several methods has been proposed in the past, including staining and fluorescence tagging. However, these approaches require the sample to be altered, often in an non-reversible way, by means of more or less complicated (bio)-chemical processing. On the other hand, label-free techniques and more specifically, Quantitative Phase Imaging (QPI), offer the advantage of being used without a specific preparation of the sample, thus allowing for example, the observation of living matter without significant drawbacks on the sample health. In this perspective, a QPI technique called Gradient Light Interference Microscopy (GLIM) is presented . This technique can be implemented on standard optical microscopes as it relies on Differential Interference Contrast (DIC) imaging that is conventionally used in biology and material science. The GLIM technique is shown as a fast and effective way to have a direct mapping of the phase gradient associated to a transparent sample by exploiting low-coherent polychromatic light that is typically available in any microscope. Examples of realistic complex samples such as collagen fibrils and cells will be provided and commented.

Authors : Andreas J. Huber Philip Schäfer
Affiliations : neaspec GmbH Eglfinger Weg2 85540 Haar Gernamy

Resume : Scattering-type Scanning Near-field Optical Microscopy (s-SNOM) is a scanning probe approach to optical microscopy and spectroscopy that achieves a spatial resolution below 20 nanometers. s-SNOM employs the strong confinement of light at the apex of a sharp metallic AFM tip to create a nanoscale optical hot-spot. Analyzing the scattered light from the tip enables the extraction of the optical properties (dielectric function) of the sample directly below the tip, yielding nanoscale resolved optical images simultaneous to topography or local spectroscopic information about a specimens reflectivity and absorption [1,2]. In latest s-SNOM applications, the combined analysis of complex nanoscale material systems by correlating near-field IR spectra with information obtained in a wider spectral range (VIS to THz frequencies) has gained significant interest. For example, the material-characteristic nano-FTIR spectra measured for nanoscale Acetaminophen (Paracetamol) particles can be directly compared with nanoscale resolved tip-enhanced Raman spectrum (TERS) obtained on the very same sample location. Further, correlative measurements of the near-field optical response of semiconducting samples like Graphene (2D) or functional SRAM devices (3D) and Kelvin Probe Force Microscopy (KPFM) measurements reveal complementary quantitative information about the local conductivity in engineered nanostructures. As a result, s-SNOM systems have the potential to characterize complex material systems by different near-field and AFM-based methods at the nanoscale for a wide range of different applications. [1] F. Keilmann, R. Hillenbrand, Phil. Trans. R. Soc. Lond. A 362, 787 (2004). [2] F. Huth, et al., Nano Lett. 12, 3973 (2012).

Authors : René Sachse1,2, Andreas Hertwig1, Denis Bernsmeier2, Michael Bernicke2, Vasile-Dan Hodoroaba1, Ralph Kraehnert2
Affiliations : 1 Federal Institute for Materials Research and Testing (BAM), 12203 Berlin, Germany; 2 Technische Universität Berlin, 10623 Berlin, Germany

Resume : Porous materials play an important role in energy applications such as batteries, photo-catalysis and electrolysis. The activity of porous materials in electrochemical reactions is highly dependent on their properties, i.e. film thickness, crystallinity, electrical conductivity, porosity and their capability to allow complete filling of pores with electrolyte. The impact of the catalysts structure on electrochemical processes can be investigated by standard rotating disc electrode experiments which, however, do not provide any information of changing material properties during the experiment. Therefore, it is highly desirable to analyze materials directly under realistic conditions of electrocatalytic measurements. We report a new setup that provides operando spectroscopic ellipsometric analyzes under water electrolysis conditions. The studied catalysts of composition IrOx and Ir/TiOx were synthesized, from solutions containing a triblock copolymer as the structure-directing agent and a metal oxide precursor in ethanol. The solutions were deposited on a conductive substrates such as polished titanium and subsequently calcined in air. The resulting catalysts are homogenous, crack-free and show templated mesoporosity with a pore wall composed of oxides from iridium or iridium and titanium which can be used as model type catalysts. We developed an electrochemical flow cell that can be mounted in a spectroscopic ellipsometer and allows spectroscopic measurements under realistic conditions of e.g. cyclovoltammetric and chronoamperometric experiments in the oxygen evolution reaction (OER). The flow cell attaches to the top of the working electrode that carries the catalyst film. A platinum counter electrode and an Ag/AgCl reference electrode are connected to the flow cell. Peristaltic pump provides a constant flow of electrolyte. From the spectroscopic data, film thickness, porosity, degree of pore filling as well as electrical and optical properties can be derived as a function of e.g. electrolyte pH, flow rate and applied potential. The contribution will assess in detail the investigation of the operando measurement and data modelling. Moreover, by fitting the measured data, the change in material properties and degree of pores filled with electrolyte or oxygen will be discussed.

Authors : Christophe Licitra, Nicolas Bernier, Chiara Sabbione, Pierre Noé
Affiliations : Univ. Grenoble Alpes, CEA, LETI, F-38000 Grenoble

Resume : Phase change materials (PCM) based on Ge-Sb-Te alloys have interesting properties for a new generation of non-volatile memories. They exhibit rapid and reversible phase transformations between crystalline and amorphous states with very different electrical and optical properties. Thus, optical reflectivity and resistivity measurements during annealing are typically used to monitor the phase transition of PCM thin films, which are amorphous in their as-deposited state. In this study, the crystallization mechanisms of different PCM, GeTe and Ge2Sb2Te5 (GST) thin films are investigated using temperature-dependent in-situ spectroscopic ellipsometry. Previous studies have demonstrated the strong impact of surface oxidation in the crystallization process of PCM films. Nucleation can occur either at the surface followed by nucleation within the remaining amorphous volume (GST case) or growth from the surface layer (GeTe case) for surface oxidized samples, or directly into the volume at a significantly higher temperature by volume (or homogeneous) nucleation for non-oxidized samples (both GST and GeTe cases). The latter were obtained by a covering of their surface in situ after deposition with an oxidation protection layer made for instance of SiN, TaN or SiOx thin films. We will show how ellipsometry can be used to monitor these two crystallization processes and thus complement the reflectivity and resistivity measurements which have certain limitations.

Authors : Tomasz M. Stawski
Affiliations : Bundesanstalt für Materialforschung und -prüfung (BAM), Division 1.3: Structure Analysis, Berlin, Germany

Resume : In recent years, we have come to appreciate the astounding intricacy of the processes leading to the formation of minerals from ions in aqueous solutions. The original, and rather naive, ‘textbook’ image of these phenomena, stemming from the adaptation of classical nucleation and growth theories, has increased in complexity due to the discovery of a variety of precursor and intermediate species. These include solute clusters (e.g. prenucleation clusters, PNCs), liquid(-like) phases, as well as amorphous and nanocrystalline solids etc.. Does it, however, mean that all the minerals grow through intermediate phases, following a non-classical pathway? In general, the precursor or intermediate species constitute different, often short-lived, points along the pathway from dissolved ions to the final solids (typically crystals in this context). In this regard synchrotron-based scattering (SAXS/WAXS/total scattering) appears to be the perfect tool to follow in situ and in a time-resolved manner the crystallization pathway because of the temporal and spatial length scales that can be directly accessed with these techniques. In this presentation we show how we used scattering to probe the crystallisation mechanisms of calcium sulfate, This system contains minerals that are widespread in diverse natural environments, but they are also important in various industrial settings . Our data demonstrate that calcium sulfate precipitation involves formation and aggregation of sub-3 nm anisotropic primary species. The actual crystallisation and formation of imperfect single crystals of calcium sulfate phases, takes place from the inside of the initial aggregates. Hence, calcium sulfate follows a non-classical pathway.

Authors : Andreas Hertwig, P. Ryšánek, L. Ivanov, Martin Kormunda
Affiliations : Federal Institute for Materials Research and Testing (BAM), Division 6.7, Surface Modification and Measurement Technique, Unter den Eichen 87, D-12205Berlin, Germany, E-mail:; J.E.Purkinje University, Faculty of Science, Department of Physics, Ceske mladeze 8, 400 96 Usti nad Labem, Czech Republic; J.E.Purkinje University, Faculty of Science, Department of Physics, Ceske mladeze 8, 400 96 Usti nad Labem, Czech Republic; Angel Kanchev University of Ruse, Faculty of Electrical Engineering, Electronics and Automation, Department of Electronics, 8 Studentska str., POB 7017, Ruse, Bulgaria

Resume : Ternary oxides have become valuable layer materials with manifold applications spanning from display technology and photovoltaics to low-E IR protection coatings. Mixed oxides based on tin (Sn) and zinc (Zn) have attracted attention as they avoid the supply problem associated with indium. In this presentation, we present work on the properties of SnxZnyOz mixed oxide layers. These layers are produced by means of a co-sputtering process involving two different targets with varying plasma power properties. The layers were investigated with spectroscopic ellipsometry to determine their thickness and dielectric function. The optical properties thus obtained are strongly correlated with the electrical conductivity of the layers, transparency, composition and electronic state of the metals. By using a combination of different analytic techniques, we can improve coating processes and find optimal combinations of material properties for different applications.

Authors : N. Nirmalananthan-Budau, D. Geißler, Bastian Rühle, U. Resch-Genger
Affiliations : Bundesanstalt für Materialforschung und -prüfung (BAM), Division 1.2 Biophotonics, Richard-Willstätter-Str. 11, 12489 Berlin, Germany.

Resume : Surface-functionalized organic, inorganic, and hybrid nanoparticles (NP) are of great interest in the life and material sciences, as they can be used e.g. as drug carriers, fluorescent sensors, and multimodal labels in bioanalytical assays and imaging applications. NP performance in such applications depends not only on particle size, size distribution, and morphology, but also on surface chemistry, i.e. the total number of surface functional groups (FG) and the number of FG accessible for subsequent functionalization with ligands or biomolecules, which in turn determines surface charge, colloidal stability, biocompatibility, and toxicity. Methods for FG quantification should be simple, robust, reliable, fast, and inexpensive, and allow for the characterization of a broad variety of nanomaterials differing in size, chemical composition, and optical properties. Aiming at the development of simple, versatile, and multimodal tools for the quantification of many bioanalytically relevant FG such as amine1,2, carboxy1,2, thiol and aldehyde3 functionalities, we designed a catch-and-release assay utilizing cleavable probes that enable the quantification of the cleaved-off reporters in the supernatant after particle separation, and thus, circumvent interferences resulting from particle light scattering and sample-inherent absorption or emission.1 Moreover, the cleavable probes allow for a complete mass balance by determining the particle-bound labels, the unbound reporters in the supernatant, the reporters cleaved off from the particles, and the groups remaining on the particle surface after cleavage. The potential of our cleavable probes for the quantification of carboxy and amino groups was demonstrated for commercial and custom-made polymer and mesoporous silica particles of varying FG densities, underlining the benefit of the catch-and-release assays as a versatile method for the FG quantification on all types of transparent, scattering, absorbing and/or fluorescent particles.1,2 Our catch-and release assay concept also allows for the determination of the relative FG orientation on micellar encapsulated quantum dots.4 In the future, our cleavable probe strategy can be easily adapted to other analytical techniques requiring different reporters, or to different types of linkers that can be cleaved thermally, photochemically, or by pH, utilizing well-established chemistry, e.g. from drug delivery systems. References. (1) M. Moser, N. Nirmalananthan, T. Behnke, D. Geißler, U. Resch-Genger, Anal. Chem. 2018, 90, 5887-5895. (2) N. Nirmalananthan-Budau, B. Rühle, D. Geißler, M. Moser, C. Kläber, A. Schäfer, U. Resch-Genger Sci. Rep. 2019, 9, 17577-17587. (3) A. Roloff, N. Nirmalananthan-Budau, B. Rühle, H. Borcherding, T. Thiele, U. Schedler, U. Resch-Genger, Anal. Chem. 2019, 91, 8827-8834. (4) D. Geißler, M. Wegmann, N. Nirmalananthan-Budau, U. Resch-Genger, “Quantification of functional groups and determination of their relative orientation on micellar encapsulated quantum dots”, manuscript in preparation.

12:00 Lunch break    
Advanced 2D and 3D charactersisation methods : Petr Klapetek and Francois Piquemal
Authors : A. Tempez, Y. Mazel, J-P Barnes, E. Nolot, S. Legendre, M. Mrad, C. Sabbione, V. Reboud, L. Casiez, J.-M. Hartmann
Affiliations : HORIBA FRANCE SAS, Palaiseau, France; Univ. Grenoble Alpes, CEA, LETI, Grenoble, France

Resume : Elemental depth distribution is nano-engineered in the materials designed for advanced microelectronic and optoelectronic components. Knowing the chemical composition of near-surface and in-depth nanostructured materials at each processing step is thus critical to develop and tune process parameters that will lead to best final device performance. Plasma profiling time-of-flight mass spectrometry (PP-TOFMS) is a rapid chemical nano resolution depth profiling technique. The fast erosion rate of the glow discharge plasma and the high-speed time of flight mass spectrometer are combined to make PP-TOFMS a suitable tool for giving fast answers to process (growth, etching) developers and thereby accelerate deployment of innovative materials. In addition to speed, other characteristics of the technique such as calibration free semi-quantification, full element coverage and easy operation contribute to make PP-TOFMS an in-line metrology tool. We will illustrate such close to process advantages for nitride materials for light emitting diodes and power electronics. For the latter, a fast feedback on the Al, In, and Ga contents has been key to understand the incorporation of unintentional gallium and design the appropriate reactor configuration and conditions. The example of surface stoichiometric modifications of GeSbTe alloys developed for phase change memories upon etching and other patterning steps will also be shown. In this case PP-TOFMS analysis comes in complement to XPS to provide in-depth information, both leading to best choice of plasma chemistry. The depth profiles of active GeSn layers for MIR optoelectronics will be presented as the Sn content in SiGeSn layer affects the carrier confinement and thus lasing performance.

Authors : Alexander Ost*(1), Jean-Nicolas Audinot(1), Tom Wirtz(1).
Affiliations : (1)Advanced Instrumentation for Ion Nano-Analytics (AINA), Materials Science and Technology Department, Luxembourg Institute of Science and Technology (LIST), Luxembourg

Resume : The trend in miniaturisation of devices is increasing the need for characterisation techniques that are capable of investigating objects in 3D at nanoscale with both structural and chemical information. In this context, we have developed a Secondary Ion Mass Spectrometry (SIMS) system and coupled it to an Orion NanoFab Helium Ion Microscope (HIM). In the standard HIM mode, the instrument provides secondary electron (SE) images with a sub-nm lateral resolution. These high-resolution SE images can be correlated with sub-15 nm resolution SIMS images to gain access to the nanoscale composition of the investigated samples. This two-dimensional correlative microscopy approach has been extended to three dimensions by creating 3D representations of nanomaterials and overlaying the SIMS acquisition onto the 3D SE representation. Therefore, photogrammetry is used i.e. the sample stage is tilted and SE images are taken at specific rotation angles with a He+ primary beam around the region of interest (ROI). The SIMS images are acquired of the ROI in-situ at normal incidence with a Ne+ primary beam and projected then onto the 3D photogrammetry representation using correspondence points. In this presentation, we will show step-by-step the workflow for 3D reconstruction and SIMS correlation for nanomaterial applications to illustrate the potential of this method for a variety of different fields. [1] T. Wirtz et al., Annu. Rev. Anal. Chem. 2019. 12:523–43.

Authors : David Uebel, Stephan Kayser, Thomas Teubner, and Torsten Boeck
Affiliations : Leibniz-Institut für Kristallzüchtung

Resume : During solution growth of crystalline silicon from an amorphous seed layer, the crystallization dynamics was up to now only observable by time consuming and destructive methods like TEM. Raman spectroscopy allows for the discrimination between amorphous and crystalline phases of substances. We have developed a Raman mapping method for the fast and non-destructive characterization of an evolving crystalline matrix within the amorphous silicon. With dwell times of just 1 s, large areas can be characterized quickly without drift of the spectrometer. Thus, all data are gained with comparable calibration and a crystallinity figure of merit can be introduced to account for signal shift and signal intensity. With a time series of otherwise identical growth runs we reveal how nanocrystalline structures evolve during the growth process. The morphology of the seed layer influences the surface morphology of the final polycrystalline Si layer strongly. The prepared Si layers serve as absorbers for novel, cost-efficient solar cell layouts.

Authors : George Koutsourakis, Yameng Cao, Sebastian Wood, James C. Blakesley, Fernando A. Castro
Affiliations : National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom

Resume : Perovskite solar cells (PSC) have demonstrated high efficiencies in recent years, with good scalability potential. The introduction of tandem devices with a perovskite top layer on silicon is also an exciting concept which has dominated record efficiencies for non-concentrator PV devices. Despite these promising aspects, stability issues are a significant obstacle for PSC to compete with established PV technologies. There are several critical factors for PSC degradation, and ageing tests require accurate environmental controls in order to distinguish different degradation mechanisms. This work presents in situ photoluminescence (PL) imaging as a tool to study the performance degradation of PSC. Using bespoke environmental chambers and ageing system developed at NPL, key environmental conditions such as atmospheric composition, spectrum and intensity of illumination, and temperature are accurately controlled for degradation tests. PL imaging provides spatial information on the initiation, propagation and classification of defects, and their correlation with current-voltage (I-V) curves. Through PL imaging and parallel I-V curve acquisition, it is demonstrated that material degradation develops around defects accompanied by a corresponding loss of short-circuit current, while the open-circuit voltage of the PSC sample is minimally affected. These analyses open a route to rapid non-contact screening of samples for removal of potential early failures and process optimisation.

Authors : Alessandro Cultrera, Gianluca Milano, Danilo Serazio, Natascia De Leo, Luca Boarino, Carlo Ricciardi, Luca Callegaro.
Affiliations : Quantum Metrology and Nano Technologies, INRIM - Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy : Alessandro Cultrera; Danilo Serazio; Luca Callegaro. Advanced Materials Metrology and Life Science Division, INRIM - Istituto Nazionale di Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy: Gianluca Milano; Natascia De Leo; Luca Boarino. Department of Applied Science and Technology, Politecnico di Torino, Duca degli Abruzzi 24, 10129 Torino, Italy: Gianluca Milano; Carlo Ricciardi.

Resume : Space-resolved measurements of electrical properties of nano structured materials play a crucial role for the realization of homogeneous transparent conductive electrodes based on thin films, 2D materials or nanowire networks. These nano structured materials are typically electrically characterised by means of four-point probe techniques, both in-line and van der Pauw configurations. These techniques, though relatively easy to implement and well established for a wide range of materials, present both i) a strong dependance of the results on the sample uniformity, and ii) limited capability to obtain space-resolved information about the conductivity of the sample. In this work, we propose the Electrical Resistance Tomography (ERT) as a non-destructive technique for space-resolved measurements of electrical conductivity of nano structured materials [1]. This technique allows, by measuring a set of four-terminal resistance at several electrodes on the sample boundaries, to reconstruct a conductivity map through the solution of an inverse problem. Examples of the application of the technique will be reported at the conference about the characterisation of transparent conductive oxide films, chemical vapour deposited graphene layers on large area substrates, and we will show first results of the application of ERT to nanowire networks. References [1] A. Cultrera and L. Callegaro, IEEE Trans. Instrum. Meas., vol. 65, no. 9, 2016.

Authors : S. Folkersma, J. Bogdanowicz, B. Vermeersch, D.H. Petersen, O. Hansen, B. Guralnikc, H. H. Henrichsen, P. F. Nielsen, L. Shiv, W. Vandervorst
Affiliations : S. Folkersma; J. Bogdanowicz; B. Vermeersch; W. Vandervorst: IMEC, Kapeldreef 75, B-3001 Leuven, Belgium. S. Folkersma; W. Vandervorst: Instituut voor Kern- en Stralingsfysika, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium. D.H. Petersen; B. Guralnikc: Department of Physics, Technical University of Denmark, Fysikvej Building 311, DK-2800 Kgs. Lyngby, Denmark. O. Hansen: DTU Nanolab, Technical University of Denmark, Oersteds Plads Building 347, DK-2800 Kgs. Lyngby, Denmark. B. Guralnikc; H. H. Henrichsen; P. F. Nielsen; L. Shiv: CAPRES – A KLA Company, DTU Science Park, Building 373, DK-2800 Kgs. Lyngby, Denmark.

Resume : Since the introduction of three-dimensional device structures such as the fin field effect transistor (finFET), the implementation of fast, in-line metrology aimed at the electrical characterization of such features has become challenging. Recently, the fully in-line micro four-point probe (µ4PP) technique has shown its capability to directly measure the resistance of nanometer-wide lines [1,2] . However, extracting the resistivity from the measured resistance requires the precise knowledge of the sample geometry, which is typically obtained from destructive and time-consuming cross-sectional Transmission Electron Microscopy (TEM) imaging. In this paper, we demonstrate an approach for extracting the resistivity of both Front-End-Of-Line (FEOL) and Back-End-Of-Line (BEOL) structures by using the Thermal Coefficient of Resistance (TCR) method [3] with µ4pp, i.e. measuring the dependence of the line resistance as a function of a varying current . To validate the technique, we show that the measured resistivity is identical on metal lines of slightly different geometries (i.e. different measured resistances), as should be expected. Finally, we study the impact of width on the resistivity of both metallic and semiconducting materials lines. [1] J. Bogdanowicz, et. al., 2018, Phys. Stat. Sol. (a), 215, 1700857 [2] S. Folkersma, et. al., 2018, Beil. Jour. of Nanotech., 9, 1863–1867. [3] C.E. Schuster, et. al., 2018, Microelectron. Reliab., 41, 239

Authors : Young-Woon Kim(1), Wonwoo Chung(1), Yonghee Lee(1), Mi-Hyang Sheen(1), and Soohong Kim(2)
Affiliations : (1) Seoul National University (2) GIG consulting

Resume : A system to make external control electron beam was designed and implemented on the scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Popular and cost-effective Arduino board was used to interface the microscope and hardware control, and the computer hosts the beam control with simple graphic-user-interface while collecting position-specific physical properties. The system was applied to 2-dimensional mapping of non-biased electron-beam induced current imaging and acquisition of spectrum-image cathodoluminescence signals in SEM and TEM. In this presentation, detail steps to build the system will be explained and possible expansion for the simple in-situ experiment will be discussed. Application results from TEM and SEM will be discussed – identification of preferential current paths from non-biased EBIC system and the diffusion length was measured from the GaN/InGaN multi-quantum well (MQW) LEDs. From the results of cathodoluminescence, it was found that the dislocations penetrating MQW tends to make blue shift in luminescence, and distributions on non-uniform optical band-gap with two distinct energies of 2.76 and 2.94 eV.

15:45 Coffee Break    
Nanoscale characterisation and sensing : Francois Piquemal and Sebastian Wood
Authors : Aymen Ben Amor*(1), Doriane Djomani(2), Stefan Dilhaire(1), Laetitia Vincent(2) et Stéphane Grauby(1)
Affiliations : (1) Univ. Bordeaux, LOMA, CNRS UMR 5798, F-33400 Talence, France; (2) C2N – CNRS, Univ. Paris-Sud, 91405 Orsay, France; *lead presenter

Resume : Nowadays an extraordinary control over the growth of nanowires (NWs) has been achieved, enabling also the integration of different types of heterostructures, which can lead to the engineering of the functional properties of the NWs. One of the many applications of NWs includes energy conversion. In this work, thermal characterization of Ge and Si allotrope heterostructured NWs is done using 3w-SThM. These NWs are composed of successive hexagonal 2H and cubic diamond 3C crystal phases along the <111> axis and are embedded in a silica matrix. The thermal characterization of these NWs revealed a strong diameter dependent decrease in the thermal conductivity, which can be predominantly ascribed to boundary scattering. In addition, we have also studied the effect of the phase transformation temperature, which influences the size and the number of 2H domains, on the NW thermal conductivity. We have deduced the NW thermal conductivity for different annealing temperatures and we have evidenced that this latter can constitute an efficient parameter to tune the thermal conductivity. During the final presentation, I will present these two studies but also the influence of doping on the thermal conductivity. These results constitute the first experimental evidence of thermal conductivity reduction in such allotrope 2H/3C heterostructured NWs.

Authors : Benjamin Vidal Montes* (1), Stéphane Coudert (2), Ahmad Zenji (1), Guillaume Duchateau (2), Jean-Michel Rampnoux (1), Stéphane Grauby (1) & Stefan Dilhaire (1)
Affiliations : (1) LOMA, Univ. Bordeaux, CNRS UMR 5798, 351 Cours de la Libération, France. (2) CELIA, Univ.Bordeaux-CNRS UMR 5107-CEA, F-33405 Talence, France

Resume : Femtosecond pump-probe technics are a powerful way to probe ultrafast heat transfers in noble metals at the nanoscale. When an ultra-short laser pulse is absorbed, it generates a time-dependent heat flux at the sample surface, the electrons reach a temperature (Te) much higher than the lattice which remains close to room temperature, generating a transient non equilibrium state. Te can be monitored by measuring the related changes of optical properties through the relative variations of the reflected probe intensity. The key issue is to determine, at subpicosecond time scale, the thermoreflectance coefficient which relates the reflected intensity variations with Te. Furthermore, this coefficient has been widely considered as a specific constant for each material resulting in a large underestimation of the temperature. Recently a temperature dependence of the thermoreflectance coefficient was shown[1], but still tough to measure at these time scales. We will present a method to quantify this coefficient during the ultrafast heating and electron-phonon non equilibrium. We will demonstrate its nonlinear dependence with the temperature and its consequences. We are now able to perform “hot electrons” temperature measurements, converting our femtosecond pump-probe experiment in an ultrafast nanothermometer. These technics open the way to real time temperature mapping of nanostructures such as tapers and nanowires[2]. References: [1] T. Favaloro, J.-H. Bahk, and A. Shakouri. Characterization of the temperature dependence of the thermoreflectance coefficient for conductive thin films. Review of Scientific Instruments 86, 024903 (2015) [2] Lozan, O., Sundararaman, R., Ea-Kim, B. et al. Increased rise time of electron temperature during adiabatic plasmon focusing. Nat Commun 8, 1656 (2017)

Authors : Muddasir Nawaz, Ramazan Kahraman, R. A. Shakoor, Sehrish Habib, Adnan Khan
Affiliations : Center of Advanced Materials, Qatar University, Qatar; Department of Chemical Engineering, Qatar University, Qatar; Center of Advanced Materials, Qatar University, Qatar; Center of Advanced Materials, Qatar University, Qatar; Center of Advanced Materials, Qatar University, Qatar.

Resume : In the present study, pH sensitive multifunctional polymeric nanocomposite coatings were developed and characterized. Towards this direction, titanium nanotubes (TNTs) were synthesized, loaded with dodecylamine (DOC) and were then reinforced into epoxy matrix to develop polymeric based nanocomposite coatings. Structural and morphological analyses were conducted using X-ray diffraction (XRD), scanning electron microscope (SEM) and transition electron microscope (TEM) techniques respectively. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) techniques were used to confirm the loading of DOC into TNTs. UV-Vis spectroscopic technique was used to study the self-release of DOC in response to the pH change. It is noticed that time dependence self-release of DOC is sensitive to the pH of the corrosive environment. The electrochemical impedance spectroscopy (EIS) results indicate that the developed nanocomposite coatings demonstrate superior corrosion resistance at pH 2 as compared to pH 5. The improved corrosion resistive properties of nanocomposite coatings at pH 2 can be attributed to the more efficient release of DOC from the nanocontainers due to higher sensitivity towards acidic medium.

Authors : Yilin Li, Prof. Joshua Edel, Dr. Aleksander Ivanov, Dr. Artem Bakulin
Affiliations : Edel Group, Department of Chemistry, Imperial College London, W12 0BZ; Ultrafast Optoelectronics Group, Department of Chemistry, Imperial College London, W12 0BZ

Resume : Single-molecule techniques have attracted great attention due to their ability to study and manipulate objects down to nano-scale while the behaviour of a specific molecule of interest is able to be addressed. The importance of these techniques is that they provide the opportunity for scientists to extract rich information and observe dynamic processes of individual molecules rather than conventional ways of averaging the ensemble. Although such techniques can achieve high spatial resolution, it commonly lacks sufficient temporal resolution, which is an obstacle in real-time observation of biomolecular dynamics, particularly for transient intermediates. This project aims to overcome this challenge by combining ultrafast spectroscopy with a single-molecule probe based on a dual-barrel nanopipette tunnelling sensor. The device is synthesised via laser-pulling dual-barrel nanopipettes before carbon filling, followed by gold deposition process. Then stability and functionality of the tunnelling junction created in the device is characterised electrochemically. Optical measurements are carried out to test the photocurrent of the device. Taken together, the results should illustrate the feasibility of conducting a time-resolved single-molecule sensing technique with high spatial resolution. Experiments on application with detecting molecules could be carried out if possible.

Authors : 1) K Govardhan, 2) A Nirmala Grace
Affiliations : 1) School of Electronics Engineering, VIT University, Vellore, Tamilnadu, 632014, India 2) Centre for Nanotechnology Research, VIT University, Vellore, Tamilnadu, 632014, India

Resume : Gas sensing is a very vital and commonly adapted process in various industries and service sectors. The gas sensing can be as mundane as pressure leak in an automotive tyre to as critical as a flammable, hazardous or even toxic gas in environments where they find a huge requirement such as industries or in hospitals. It is highly crucial to detect the leakage of gases in these environments to maintain operability of some systems or prevent catastrophic incidents in others. A variety of gas sensors have been developed to sense these gases present either individually or as mixture with other gases. The reliability of a gas sensor is highly dependent on the gas sensor calibrating or testing chamber. The credibility of the gas sensing chamber would dictate the gas sensors performance. A gas sensor needs to be observed or characterized for its characteristic such as sensitivity, selectivity, temperature dependent response variation, sensing accuracy and precision, repeatability, response towards the exposed gas, response time etc. These characteristics can be accurately studied only when the behavioural characteristics of the gas chamber is predetermined and well characterized. The paper intends to propose a flow metric based gas sensing chamber as against the conventional volumetric chamber and analyses the flow nature in the chamber. The chamber is designed with single inlet port and single exhaust vent or outlet port. The placement of the substrate holder with respect to the chamber dimensions, flow characteristics in the chamber has been optimized to provide a laminar flow over the substrate which would result in higher sensing ability of the gas sensor. The paper also deals with the boundary layer suppression to provide maximal gas flow over the substrate, thereby enhancing the chance of sensing by the gas sensor. An integrated heater is also provided below the substrate holder which would be required due to the fact that some gas sensors operate at high temperatures for their optimal performance. Study on heat propagation from the heater onto the substrate holder is also involved. The flow characteristics of the entire chamber was analysed especially at the inlet port, over the substrate and at the outlet port. The paper focuses on complete modelling of gas sensing chamber, fluid dynamic studies of gas flow inside the chamber, optimal placement of substrate, optimal angling of the substrate facing the gas flow and the heat propagation from the heater onto the substrate holder.

ALTECH 2020 poster session : Burkhard Beckhoff and Marie-Christine Lépy
Authors : Markys Cain, Paul Thompson, Didier Wermeille, Peter Finkel, Margo Staruch
Affiliations : Electrosciences Ltd; University of Liverpool The XMaS beamline ESRF Grenoble France; University of Liverpool The XMaS beamline ESRF Grenoble France; US Naval Research Laboratory, Washington, DC 02375, USA; US Naval Research Laboratory, Washington, DC 02375, USA;

Resume : Recently it was demonstrated that a stress biased [0 1 1] cut relaxor ferroelectric Pb(In1/2Nb1/2) O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystal can generate reversible strain >0.35% at low field of order 0.1MV/m[1], which was attributed to an interferroelectric phase transition marked by a sharp jump in strain. These high levels of strain are ?captured? by applying a modest mechanical compressive stress to the sample whilst exciting it electrically, which drives the ferroelectric rhombohedral FR - ferroelectric orthorhombic FO phase transition in these domain engineered relaxor ferroelectric single crystals. The nature of the transition under both stress and E-field was explored for Pb(In1/2Nb1/2) O3-Pb(Mg1/3Nb2/3)O3-PbTiO3, at the XMaS offline x-ray laboratory source, ESRF, Grenoble, France. Electric field and stress was applied to the sample using a novel stress rig purposely designed to fit the diffractometer. Stress, field, charge, electric polarisation and strain were all measured in operando. Preliminary results will be presented showing the evolution of the complex phase transitions which highlights the requirement to perform in operando metrology. This work was funded through the European Metrology Research Programme (EMRP) Project Grant Number: 16ENG06 ADVENT, and ONRG - NICOP Project Number: N62909-18-1-2008 Electrosciences Ltd. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

Authors : Zhongquan Liao, Yvonne Standke, Jürgen Gluch, Petr Brázda, Jaromír Kopeček, Mariana Klementová, Lukas Palatinus, Ehrenfried Zschech
Affiliations : Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Maria-Reiche-Str. 2, 01109 Dresden, Germany; Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Maria-Reiche-Str. 2, 01109 Dresden, Germany; Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Maria-Reiche-Str. 2, 01109 Dresden, Germany; Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221 Prague, Czech Republic; Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221 Prague, Czech Republic; Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221 Prague, Czech Republic; Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, 18221 Prague, Czech Republic; Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Maria-Reiche-Str. 2, 01109 Dresden, Germany

Resume : The groundbreaking work in 2004 leads an unprecedented boom in interdisciplinary researches for 2D materials. Due to superior properties, 2D materials promise tremendous potential applications in electronics, optoelectronics, membranes, energy storage and generation, catalysis, sensing and so on. Silicene, a monolayer of silicon atoms arranged in a honeycomb lattice, is excellently compatible with the materials used in today’s semiconductor manufacturing. In this study, silicene-terminated CaSi2 was cleaved inside a TEM using an in-situ manipulator. HRTEM studies on a standard lift-out lamella performed from several crystallographic orientations confirmed the cell parameters of a = 3.7 Å and c = 30.60 Å, and allowed to determine its exact orientation in the SEM/FIB system. A FIB procedure with corrected tilting and rotating angles has been developed to ensure that the tensile force applied by the manipulator is perpendicular to the (0 0 1) plane, and that the [1 0 0] pole axis could be used for HRTEM imaging. A sharp and flat cleavage interface with a length of more than 1 µm was observed in one in-situ experiment. HRTEM images from multiple regions confirmed that the flat cleavage followed the (0 0 3) plane of the CaSi2 crystal. The current in-situ study demonstrates that a surface sheet with silicene-like atomic arrangement can be mechanically exfoliated from silicide compounds.

Authors : H. Ben Jbara a,b*, M. Arab Pour Yazdi c and M. Kanzari a,d
Affiliations : a Université Tunis El Manar, Ecole Nationale d’Ingénieurs de Tunis, Laboratoire de Photovoltaïque et Matériaux Semi-conducteurs, BP 37, Le belvédère, 1002 Tunis, Tunisie. b Université de Tunis, Ecole Nationale Supérieure d’Ingénieurs de Tunis, , 13 Ave Taha Hussein Montfleury, 1008 Tunis, Tunisie. c Institut FEMTO-ST, UMR 6174 CNRS, Univ. Bourgogne Franche-Comté, UTBM, Site de Montbéliard, F-90010 Belfort Cedex, France. d Université de Tunis, Institut Préparatoire aux Etudes d’Ingénieurs de Tunis, Montfleury 1089 Tunis, Tunisie Corresponding author:

Resume : Cu-Fe-O thin films were co-sputtered from metallic Cu and Fe targets in the presence of a reactive argon and oxygen gas mixture. Evolution of the coatings composition as a function of the discharge current dissipated on each target allowed to obtain convenient composition. The influence of annealing temperature under vacuum and air atmosphere on physico-chemical properties of the films was investigated. The elaborated films were annealed at 380°C, 450°C and 550°C under vacuum and air atmosphere to achieve delafossite structure. The X-ray diffraction analysis revealed the presence of CuFeO2 with a preferred orientation along (006) plane. CuFe2O4 and CuO as the secondary phases were detected. Electrical properties have been investigated by ac impedance spectroscopy over a wide range of temperature up to 873 K starting from room temperature in the frequency range 5Hz–13MHz. The complex impedance plots display one semicircle with equivalent circuit functions as typical parallel RC. The analysis of conductivity indicates that both AC and DC conductivities of materials increase with increasing temperature. The activation energy values calculated from DC conductivity and angular frequency relaxation are almost identical, indicating that the conduction mechanism was thermally activated and was assured by hopping between localized states.

Authors : N. Khemiri, A. Jebali, M. Kanzari
Affiliations : Université Tunis El Manar, Institut Préparatoire aux Etudes d’Ingénieurs El Manar, Campus Universitaire Farhat Hached, B.P 244, Tunis 2092, Tunisie. Université Tunis El Manar, Ecole Nationale d’Ingénieurs de Tunis, Laboratoire de Photovoltaïque et Matériaux Semi-conducteurs, B.P 37, 1002,Le Belvédère Tunis, Tunisie. Université de Tunis, IPEITunis Montfleury, Laboratoire de Photovoltaïques et Matériaux Semi-conducteurs-ENIT.

Resume : Tin antimony sulfide Sn-Sb-S (TAS) thin films were deposited on glass and Si substrates using vacuum evaporation technique. Spectroscopic ellipsometry (SE) is a non-destructive method that we used to study the optical properties of the films. The SE measured data were analyzed by considering double layer optical model for all the samples, with the two Tauc-Lorentz oscillators and Gaussian dispersion relations. From the ellipsometric study, we extracted the thickness, absorption coefficient, band gap energy, refractive index and extinction coefficient of all samples. All the films exhibited high absorption coefficient a in the visible range (>105 cm-1). The values of the band gap energy Eg of Sn-Sb-S thin films deposited on glass varied from 1.13 to 1.48 eV. For the samples deposited on silicon, the band gap energy Eg varied from 1.44 to 1.72 eV. The spectral dependencies of the refractive index and the extinction coefficient of Sn-Sb-S thin films were determined and analyzed.

Authors : P.Hönicke, U. Waldschläger, A. Gross, M. Krämer, T. Wiesner
Affiliations : Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany; Bruker Nano GmbH, Am Studio 2D, 12489 Berlin, Germany; Bruker Nano GmbH, Am Studio 2D, 12489 Berlin, Germany; AXO Dresden GmbH, Gasanstaltstr. 8b, 01237 Dresden, Germany; Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany

Resume : Grazing-Incidence X-ray fluorescence analysis is a very powerful technique for the in-depth analysis of many types of technologically relevant samples, e.g. nanoparticle depositions, shallow dopant profiles or thin layered samples. However, the extraction of the depth dependent information about the sample is usually based on a modelling of the experimental data. This requires a profound knowledge on the geometrical parameters of the employed setup, especially the incident beam as well as the detector aperture parameters. Together they determined the incident angle dependent so-called effective solid angle of detection which must be known in order to model any experimental data set. In this work, we demonstrate how the instrument parameters, which determine the effective solid angle of detection can be determined using a well-known calibration sample for a Bruker S4 T-STAR instrument.

Authors : Filipa R. F. Simoes, Edy Abou-Hamad, Jasmin Smajic, Nitin M. Batra, Pedro M. F. J. Costa
Affiliations : King Abdullah University of Science and Technology (KAUST)

Resume : Carbon materials are very useful for a number of applications. However, the possible presence of foreign species such as transition metals, originating from the synthesis or processing steps, is often overlooked. This is particularly relevant when studying powders of these materials. For instance, the extent to which these foreign species alter the electrochemical profile of carbons and affect their performance (in energy storage and conversion systems) is still not fully recognized. Molten salt oxidation (or fusion) is a promising approach to analyse the chemical composition of carbon materials via, for instance, the spectral analysis of their plasmas. Here, three commercial carbon powders, relevant for electrochemical applications, were selected to evaluate the versatility of fusion as a pre-treatment process for elemental analysis with inductively coupled plasma optical emission spectroscopy (ICP-OES). The interaction of the flux, a lithium borate salt, with the carbons was investigated following the examination of their post-fusion residues. For the three carbons, the degree of structural degradation varied. Generally, the doping with Li and/or B (whether substitutional or interstitial) was low to non-existent.

Authors : Wählisch, A.*(1), Seim, C.(2), Lubeck, J.(1), Unterumsberger, R.(1), Hönicke, P.(1), Kayser, Y.(1), Hoehl, A.(1), Fleischmann, C.(3), Rehbein, S.(4), Dehlinger, A.(2), Haidl, A.(5), Weimann, T.(1), Dai, G.(1) & Beckhoff, B.(1).
Affiliations : (1)Physikalisch-Technische Bundesanstalt (PTB), Germany (2)Technische Universität Berlin (TUB), Germany (3)imec, Belgium (4)Helmholtz-Zentrum Berlin (HZB), Germany (5)University of Applied Science Koblenz, Germany * lead presenter

Resume : As functional devices in many areas of application steadily get smaller and require material systems not only at the microscale but nanoscale, the demand for analytical high-resolution methods is increasing in the same manner. X-ray spectroscopy (XRS) is a nondestructive technique widely used to qualitatively and quantitatively characterize material systems. However, vibrations with amplitudes in the order of the desired resolution, caused from the surrounding environment, may disturb any resolution sensitive measurement. We present a novel instrumentation for synchrotron radiation based scanning XRS, where all relevant optical elements are mounted on a single platform. This compact setup minimizes vibrations, enabling a spatial resolution in the nm regime with scanning transmission X-ray microscopy (STXM) and scanning X-ray fluorescence analysis (XRF). Both emitted fluorescence radiation and transmitted radiation are detected with calibrated X-ray detectors. We demonstrate a reference-free quantification method based on XRF on a nanostructured germanium sample. To determine the mass deposition of germanium, the lateral size of the incident beam has to be known. In initial experiments we achieved a beam with full width at half maximum of about 100 nm, which is in line with the probed sample dimensions.

Authors : Ankur Pandey, Partho S G Pattader
Affiliations : Department of Chemical Engineering, IIT Guwahati, Assam, 781039; Department of Chemical Engineering, IIT Guwahati, Assam, 781039, Center for Nanotechnology, IIT Guwahati, Assam, 781039.

Resume : The on demand pattern generation on a substrate using phase separation in blend polymer mixture finds a broad spectrum of applications like fabrication of self-cleaning and super-hydrophobic surfaces, robust membrane materials etc. In the present study, a simple and novel technique for the generation of complex patterns was demonstrated using polymer-polymer bilayer system supported over silicon wafer. There is a strong evidence that the nature of a labile under-layer polymer affects the phase separation of the bilayer and the overall morphology. For instance, when a blend of polystyrene (PS)-polymethyl methacrylate (PMMA) in toluene was spun coat over thin layers of PMMA, blend or random block copolymer, no phase inversion was observed up on thermal annealing. However, the phase inversion took place in the case when the PS-PMMA blend was spun coat on PS (h ~ 50 nm) and then thermally annealed. Arguably, the surface energy of the polymer present in the bottom layer strongly affects the phase inversion in the blend top layer. Later, by selective solvent etching fascinating patterns were generated as characterized by atomic force microscopy. This providing the generic guidelines for complex pattern generation using different polymer combinations with distinct functionalities.

Authors : François Ziadé
Affiliations : Laboratoire National de Métrologie et D'essais

Resume : The emergence of 5th Generation (5G) telecommunications the Internet of Things (IoT) with 50 billion connected devices will strongly increase the demand for energy due to the continuous power consumption of the electronic devices needed to deliver these technologies. Improvement of the energy efficiency of devices and processes is therefore a key component for sustainable development of future products. Due to restrictions in current scaling strategies and dramatic thermal issues (particularly in wireless systems), semiconductor and electronics industries require the introduction of novel materials, more complete component characterisation and more efficient power management at the system level that will lead to the development of novel ultra-low power devices. To support industry in facing these challenging issues the European project in Metrology ADVENT aims to establish a robust metrology framework for in-situ, in-operando and Multiphysics characterisation of advanced materials and components, and for reliable and accurate data for an efficient power management system. This talk will provide an overview of the top - down approach proposed in ADVENT to improve energy efficiency at every development stage of future electronic products: system, component and material. A special focus will be given on material and component challenges for the next generation of electronic devices required in 5G and IoT applications.

Authors : Anna Charvátová Campbell, Marek Havlı́ček, Jan Šrámek, Miroslav Valtr, Petr Klapetek, David Nečas
Affiliations : Czech Metrology Institute, Okružnı́ 31, 638 00 Brno, Czech Republic; CEITEC BUT, Purkyňova 123, 612 00 Brno, Czech Republic; Czech Metrology Institute, Okružnı́ 31, 638 00 Brno, Czech Republic; Czech Metrology Institute, Okružnı́ 31, 638 00 Brno, Czech Republic; Czech Metrology Institute, Okružnı́ 31, 638 00 Brno, Czech Republic; CEITEC BUT, Purkyňova 123, 612 00 Brno, Czech Republic;

Resume : Nanoindentation is the most popular method for the measurement of hardness and elastic modulus of nanoscale materials, such as thin films, nanocomposites and other nanostructured materials. The correct evaluation depends crucially on the correct evaluation of the so-called area function, which depends on the shape of the indenter tip. For many applications at the nanoscale, it is desirable to measure at very low contact depths which requires precise knowledge of the area function even at very shallow depths. Unlike the standard method for area function calibration using a reference sample, the direct measurement of the tip shape using atomic force microscopy and coordinate metrology offers full information about the shape as well as traceability. Although the idea of the procedure is simple and well-known, details of the measurement process and the evaluation are rarely discussed. In this contribution we present approaches and recommendations to the measurement and evaluation of the tip shape. Experimental settings, their effect on the measured data and appropriate corrections of will be discussed. The combination of AFM and coordinate measurement instruments will be addressed. Sources of uncertainties will be analyzed and evaluated, the uncertainty budget will be modelled using Monte Carlo simulations.

Authors : Claudia Zech [1], Marco Evertz [2], Markus Börner [2], Yves Kayser [1], Philipp Hönicke [1], Malte Wansleben [1], Sascha Nowak [2], Burkhard Beckhoff [1]
Affiliations : [1] Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany; [2] Münster Electrochemical Energy Technology, Corrensstraße 46, 48149 Münster, Germany

Resume : The increasing demand for secondary electrochemical storage devices requires well characterized and working battery systems. Each battery suffers from degradation effects which lead to capacity fading and life cycle reduction. The single mechanisms vary for different types of batteries. With electrochemical methods the fading can easily be monitored, but to understand the underlying chemical and physical properties which are responsible for the capacity reduction further analytic techniques are needed. We demonstrate the possibilities offered by X-ray spectrometry to investigate degradation mechanisms for an exemplary Lithium-Ion battery (LIB). We present how X-ray fluorescence analysis (XRF), near edge X-ray absorption fine structure (NEXAFS) and resonant inelastic X-ray scattering (RIXS) can contribute to a deeper insight by explaining which information each method can reveal about the cell’s properties. The element of interest is manganese since the cathode material consists of lithium nickel manganese cobalt oxide (NMC). The combination of the different methods generates a clearer understanding of the chemical processes in the battery and can therefor help to improve the performance by using enhanced material combinations.

Authors : Arnas Naujokaitis, Vaidas Pačebutas, Jan Devenson, Renata Butkutė, Andrejus Geižutis, Sandra Stanionytė, Martynas Skapas, Mindaugas Kamarauskas, Bronislovas Čechavičius, Mária Čaplovičová,2 Viliam Vretenár, Xiaoyan Li, Mathieu Kociak, Arūnas Krotkus, Tadas Paulauskas.
Affiliations : Center for Physical Sciences and Technology, Saulėtekio al. 3, Vilnius, Lithuania. STU Centre for Nanodiagnostics, Slovak University of Technology, Vazovova 5, Bratislava, Slovakia. Laboratorie de Physique des Solides, University of Paris, 91400 Orsay, France.

Resume : The bismide GaAs1-xBix alloy has experienced an extensive amount of research and represents the emerging class of bismuth-based III-V semiconductors. It is a promising candidate for multijunction solar cells applications, infrared lasers, and photodetectors. In this study, we synthesize nominally 1.0 eV bandgap bulk GaAs1-xBix layers aimed at photovoltaic applications and investigate the structure-property relationships of this material. Solid-source molecular-beam epitaxy is used to grow the bismides on flat and low-angle offcut (001) GaAs and Ge substrates. Scanning-transmission electron microscopy techniques are employed to elucidate the modes of Bi distribution in several distinct samples. Atomic-resolution high-angle annular dark-field imaging and numerical quantification using scattering cross-sections are employed to analyze atomically-abrupt GaAs-GaAsBi interfaces and the onset of CuPt-type ordering. The analysis is also performed on GaAsBi antiphase boundaries showing the distribution of various point defects. We use atomically-resolved X-ray energy dispersive spectroscopy to quantify the CuPt order-parameter and to chemically map Bi in the vertical composition modulation grown GaAsBi sample. Monochromated electron energy-loss spectroscopy is employed to measure bulk plasmon energy shifts in phase-separated domains, indicating the strain-state changes in this alloy. Photo-luminescence, X-ray diffraction, and charge-carrier lifetime measurements are also presented to provide a comprehensive picture of the alloys properties and its potential in photovoltaics.

Authors : Christoph Metzke, Fabian Kühnel, Jonas Weber, Günther Benstetter
Affiliations : Department of Electrical Engineering and Media Technology, Deggendorf Institute of Technology, Dieter-Görlitz-Platz 1, 94469 Deggendorf, Germany

Resume : The present trend of electronic miniaturization manifests in rather smaller devices, in which heat distribution could become a limiting factor. Therefore, heat transfer processes in micro- and nanoscale devices in the field of energy applications as well as thermoelectric materials have gained continuously rising interest over the past decades. Scanning thermal microscopy (SThM) is an atomic force microscopy (AFM) based method to analyse local thermal conductivities of layers with thicknesses ranging from several nm to µm. In this work we investigate the SThM method applied to ultrathin films by performing 2D and 3D finite element method (FEM) simulations using the software tool COMSOL® Multiphysics (CM). The focus of the simulations is to explore the limits of SThM regarding materials such as hexagonal Boron Nitride (h-BN) and gain new insights into the heat transfer of ultrathin films. Therefore, we investigated the cantilever used by means of scanning electron microscopy (SEM) and transferred the cantilever geometry to CM. Step by step we simulated the displacement of the cantilever, the mechanical contact area between tip and sample and finally the heat transfer process between tip and the ultrathin film. Also, practical SThM measurements of ultrathin films are then compared to the theoretical FEM simulations. The simulations provide new insights into the heat transfer process of the SThM method applied to ultrathin films below 20 nm and reasonable meshing strategies.

Authors : A. ZENJI *(1), B. VIDAL MONTES (1), J.M.RAMPNOUX (1), S.GRAUBY (1) & S. DILHAIRE (1).
Affiliations : (1)University of Bordeaux, LOMA, CNRS UMR 5798, F-33400 Talence, France

Resume : Transient heat transport is governed by the electrons and the phonons in many nanoscale applications. A new observed thermal behavior in the alloys called superdiffusive regime based on the Levy dynamics[1] is present at specific space and time scales. It is an intermediate regime between the ballistic and diffusive regimes, in which usually govern the phonon transport. The frequency range of this regime is accessible through the high-resolution 1 THz spectral bandwidth, obtained by the femtosecond pump-probe Heterodyne[2] experiment patented by LOMA. This broad spectral bandwidth makes this technic a phononic spectrometer. In this context, to measure the phonon spectrum, a transducer of a few tens of nanometers is deposited on top of the layer of interest. This transducer should be a metallic film with high thermal conductivity chosen to maximize the absorption of the laser in the sample and to make a heat reservoir as well. Moreover, it transfers its energy to the layers underneath and permits them to probe their thermal behavior optically. This transducer hence plays an essential role in the description of the sample spectral response. This part of our work will consist of characterizing the thermal behavior of the Au and Al transducer with a Two Temperature Model. The method presented will make it possible to choose the most efficient transducer in order to obtain a broad spectral bandwidth, which will enable an optimized analysis of the superdiffusive regime in the layers underneath. References: 1. B. VERMEERSCH, J. CARRETE, N. MINGO, AND A. SHAKOURI, “Superdiffusive Heat Conduction in Semiconductor Alloys. I. Theoretical Foundations,” Phys. Rev. B, vol. 91, 2015. 2. S. DILHAIRE, G. PERNOT, G. CALBRIS, J. M. RAMPNOUX, AND S. GRAUBY, “Heterodyne Picosecond Thermoreflectance Applied to Nanoscale Thermal Metrology,” J. Appl. Phys., vol. 110, 2011.

Authors : Yves Kayser 1, Malte Wansleben 1,2, Ina Holfelder 1, Jan Weser 1, and Burkhard Beckhoff 1
Affiliations : 1 Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany 2 Helmholtz-Zentrum Berlin f ür Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany

Resume : We will present a calibratable and compact high energy resolution wavelength-dispersive spectrometer based on the von Hamos geometry for XES and RIXS in the photon energy range from 2.4 keV to 19.0 keV. Using one or two full-cylindrical highly annealed pyrolytic graphite crystals as dispersive elements, the measurements can be either optimized towards a large solid angle of detection resulting in high detection efficiency or towards an optimized resolving power. The chemical speciation capability of the device is demonstrated on the basis of different transition metal compounds. The calibration of the instrumental response of the presented wavelength-dispersive spectrometer enables an accurate determination of binding state related structures in X-ray spectra, thus enabling reliable identification and discrimination capabilities in combination with calculations based on the OCEAN code. Furthermore the calibratability of the experimental setup was made profit of to determine L-shell atomic fundamental parameters of gadolinium.

Authors : Kaikai Li, Dongmei Lin, He Huang, Dongqing Liu, Baohua Li, San-Qiang Shi, Feiyu Kang, Tong-Yi Zhang, and Limin Zhou
Affiliations : Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong, China Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China Shenzhen Key Laboratory on Power Battery Safety Research and Shenzhen Geim Graphene Center, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China Materials Genome Institute, Shanghai University, 333 Nanchen Road, 200444 Shanghai, China

Resume : It has long been recognized that Li-ion batteries do not perform well at low temperatures, which presents a significant barrier to their application in the electric vehicle and aerospace industries. However, a fundamental understanding of the temperature dependence of the lithiation-induced phase transitions and electrochemical performance of electrode materials remains lacking. In this study, we discover a distinct and unusual temperature dependence in the phase transition of anatase TiO2 nanoparticles on dynamic Li+ intercalation, with a decrease in temperature resulting in the formation of a supersaturated solid solution phase. Thermodynamic analyses show that the supersaturated phase is more stable at low temperatures. Further kinetic analyses reveal that Li redistribution is facilitated at high temperatures while limited at low temperatures due to the sluggish Li transportation across the electrolyte-electrode interface. This difference manifests as a thermodynamically-controlled particle-to-particle phase separation at high temperatures and a kinetically-controlled formation of a supersaturated solid solution phase at low temperatures. Enhancing the interfacial kinetics and interconnectivity of the active materials proves to be an effective means of weakening the dependence of phase transitions on temperature and facilitating phase separation, resulting in improved electrochemical performance at low temperatures. This study provides, for the first time, a comprehensive and in-depth understanding of the temperature dependence of the lithiation-induced phase transition in many-particle intercalation electrodes, which has important implications for the development of the next generation of all-climate rechargeable batteries.

Authors : Seung Beom Kang, Young Soo Park, Ji Yeon Kim, Sang Won Lee, Ji-Young Hwang, Won-Seok Kim
Affiliations : Research center for carbon convergence materials, Korea Institute of Carbon Convergence Technology

Resume : Since its introduction a few decades ago, Terahertz time-domain spectroscopy has emerged as a prominent technique to investigate the high frequency properties of carbon nanotubes (CNTs), CNT/polymer composites in a non-contact and non-invasive way. MWNT/HDPE composite with 1, 3, 5 and 7% MWNT content by weight were fabricated using a twin screw extruder and an injection molding machine. THz optical and electrical properties of MWNT/HDPE nanocomposites have been studied in the frequency range of 0.2~4.0 THz using THz time-domain spectroscopy in transmission geometry at room temperature under dry air atmosphere. THz refractive index, permittivity and conductivity have been extracted from the measured THz pulses. It was found that optical and electric properties can be tuned by changing the MWNT weight fraction. The Drude-Lorentz model together with the Maxwell-Garnet effective medium theory is applied to investigate the transport parameters such as plasma frequency, damping rate, etc. As the crystallization of the polymer composites is having influence on refractive index and dielectric function in the THz region, it should be noted that an increase of host dielectric constant is related to the nucleation and growth of crystallites in HDPE matrix by adding MWNTs. The obtained host dielectric εi clearly increased with increasing MWNT concentration.

Authors : J. Morán, A. Delvallée, F. Piquemal
Affiliations : Laboratoire national de métrologie et d'essais, 29 avenue Roger Hennequin, 78197 Trappes Cedex, France

Resume : The Scanning Microwave Microscope (SMM) consists of an atomic force microscope (AFM) interfaced with a vector network analyzer (VNA) operating at GHz frequencies. This non-destructive quantitative technique is currently used to determine electrical properties of nano-sized electronics devices or nanomaterials such as semiconductor thin films and nanowires, high-permittivity dielectrics, graphene and 2D materials, etc, through local impedance measurements. Here we present quantitative permittivity measurements on different dielectric materials. The traceability to the International System of units (SI) is realized by applying a modified Short Open Load (SOL) calibration method for the one-port VNA using three known capacitance standards. These three standards are established from a calibration kit composed of a large number of Metal-Oxide-Semiconductor (MOS) micrometer-sized capacitors fabricated on a single chip with capacitance values C ranging from 0.1 fF to 10 fF. Gold circular electrodes of different diameters have been deposited on the dielectric thin films under study to define capacitances to be measured by the calibrated SMM. The “unknown” dielectric samples are placed close to the calibration kit so that the SMM calibration data are preserved. A complete uncertainty budget is established leading to a combined type uncertainty of about 10 % in relative value (one standard deviation) on the measured permittivity values.

Authors : ?. Ril, I. Fedorchenko, S. Marenkin, O. Rabinovich, A. Savchuk
Affiliations : NUST MISIS, RAS Institute named Kurnakova

Resume : The interaction between the CdAs2 semiconductor and the ferromagnet MnAs was investigated in the concentration range up to 60 mol% MnAs. Liquidus lines were created. It was shown that between the semiconductor and the ferromagnet the eutectic is forming with coordinates - 6 mol% MnAs and Tm=614 °C. The liquidus lines temperatures, according to the data of melting effects, turned out to be higher than according to crystallization effects. This is due to the tendency for cadmium diarsenide vitrification. MnAs solubility in CdAs2 was ? 1 mol%. Magnetic properties measurements show that CdAs2 - MnAs alloys are ferromagnets (Tc=315 K). The magnetization in them increased with the MnAs content rise. For quenched samples with sizes of ferromagnetic inclusions ? 40 nm, a negative magnetoresistance effect of 2-3 % in the saturation magnetic field is characteristic. This is interesting for CdAs2 with MnAs magnetically granular structures based alloys creation. These data supplemented by the differential scanning calorimetry results. The thermal effect of the conversion from tetragonal (ferromagnetic) to hexagonal (paramagnetic) MnAs modification was observed in the samples. The temperature of the effects correlates with the data for the Tc determination from magnetic measurements.

Authors : Ismo T. S. Heikkinen, Hendrik Kaser, George Koutsourakis, Sauli Virtanen, Sebastian Wood, Emma Salmi, Michael Kolbe, Fernando A. Castro, and Hele Savin
Affiliations : Aalto University, Department of Electronics and Nanoengineering, Tietotie 3, 02150 Espoo, Finland; Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, D-10587 Berlin, Germany; National Physical Laboratory, Hampton Road, Teddington TW11 0LW, United Kingdom; Beneq Oy, Olarinluoma 9, FI-02200 Espoo, Finland

Resume : Atomic layer deposited aluminium oxide is the material of choice for the surface passivation of silicon, especially in the case of nanotextured light absorbing surfaces. The excellent passivation performance of aluminium oxide is based on its good interfacial properties with silicon as well as the high negative charge of the passivating film. Stable surface passivation performance is vital for commercial photovoltaic devices making use of the nanostructured silicon surfaces, such as sensitive photodetectors and high-efficiency solar cells. Recently, we showed that damp heat exposure and light soaking can cause significant degradation of aluminium oxide surface passivation, but the exact degradation mechanisms require further studies. In this work, we investigate how damp heat exposure and light soaking affect aluminium oxide passivation films using Photoelectron Emission Spectroscopy (PES). Our results showed no differences between the undegraded and degraded samples regarding the positions or the area of the peaks corresponding to Al2p, Si2p or Al2s orbitals. However, significant differences were observed in the areas of the peaks corresponding to O1s orbitals close to 533 eV. These findings indicate that damp heat and light soaking conditions primarily affect the bonding of oxygen in the aluminium oxide films.

Authors : 1-2 Irdi Murataj, 2 Fabrizio Pirri, 1 Luca Boarino, 1 Natascia De Leo, 3 Michele Laus, 1 Federico Ferrarese Lupi
Affiliations : 1 Istituto Nazionale di Ricerca Metrologica (INRiM), Strada delle Cacce 91, 10135, Torino, Italy 2 Politecnico di Torino, Corso Duca degli Abruzzi, 24, Torino, Italy 3 Università del Piemonte Orientale ‘‘A. Avogadro’’, Viale T. Michel 11, 15121, Alessandria, Italy

Resume : The miniaturization processes involved in the semiconductor industry and in nanostructured device fabrication requires the parallel implementation of suitable standards for the dimensional characterization of structures having a minimum features size at sub-10 nm level. Therefore, new types of reference samples for traceable measurement are needed for length metrology at the nanoscale. In this context one interesting solution in order to satisfy this lack is represented by the directed self-assembly (DSA) of block copolymers (BCPs) combining top-down approach of conventional lithographic techniques with bottom-up BCPs capability to phase separate into high density features of different shapes at the nanometric scale. Recently we have demonstrated that the possibility to carefully tune the characteristic dimensions of the nano-domains confined inside periodic gratings, allows envisioning a strategy to use the DSA of BCP as a tool for the fabrication of lateral length standards. List of references: 1. ACS Appl. Mater. Interfaces, 9 (18), 15685–15697, 2017

Authors : B. Kalas (1), M. Serényi (1), G. Sáfrán (1), M. Stoica (2), M. Gartner (2), M. Fried (1), P. Petrik (1)
Affiliations : (1) Centre for Energy Research, Konkoly-Thege Miklós Str. 29-33, 1121 Budapest, Hungary; (2)Institute of Physical Chemistry, Romanian Academy of Sciences, 202 Splaiul Independentei Str., 060021 Bucharest, Romania

Resume : The demand for further improvement in the field of label-free biosensing is one of the most crucial topics of life science nowadays. For this purpose numerous optical methods and combined techniques have been developed and new sensing structures have also been introduced in the last couple of years. One of the most widespread methods is the surface plasmon resonance (SPR) spectroscopy which utilizes the evanescent electromagnetic field as a sensing probe in liquid ambient. This evanescent field emerges from the coupled incident light and the collective electron oscillation on the surface of a thin metallic layer. Combining SPR with spectroscopic ellipsometry is a common technique that has several advantages, e.g. the detection of the phase information leads to an enhanced sensitivity. Other possible improvement is the utilization of new materials or layer systems, e.g. using a Ag layer instead of Au, since Ag has more favorable properties regarding the biosensing purposes. Other materials and metal alloys have also been introduced as promising plasmonic metarials. In this study a novel layer system is presented consisting of an alloy layer of Ag and Al and also a SiO2 waveguide layer on top of it. The alloy layer was realized with the so-called combinatorial sputtering technique that makes possible that all the possible composition values of the two materials (from 100% Ag to 100% Al, with linear change along the sample) are presented only on one sample. Subsequently the biosensing properties of this layer are demonstrated by a combined SPR-SE measurement of a protein adsorption process. (OTKA K131515, OTKA K129009 and M-ERA.NET VOC-Detect projects is greatly acknowledged.)

Authors : Francis, H. *(1, 2), Ruff, Z. (1, 2), Grey, C.P. (1, 2), Bronstein, H. (1, 2)
Affiliations : (1) University of Cambridge (2) The Faraday Institution

Resume : Fluorescence chemosensors based on organic ionophores have long been investigated as a selective and sensitive method of monitoring various metal ions. Immobilisation of these molecules onto optical fibres has also emerged as an avenue for efficient, real-time sensing of metal ions, suitable for in-situ measurement. Surface-functionalization of exposed-core optical fibres has successfully been used to develop optical probes for certain metal ions.[1,2] However, a key issue remains the reliable and efficiency surface-functionalization of silica. We present a new fluorescence Li+-sensing platform based on a single-step functionalization of silica glass with a novel dye. The dye is based on a naphthalene diimide core and an aza-crown-ether ionophore, displaying altered absorbance and “turn-on” fluorescence in the presence of Li+ in solution and on grafting to silica. [3] Functionalization of the dye with a trialkoxysilane group enabled covalent grafting to silica in a single step without pre-treatment of the surface. This is the first example of single-step surface functionalization of silica using any kind of fluoroionophore. This system has potential biological application and is currently targeted towards making in-situ measurements of [Li+] in battery electrolytes. [1] Ruan, S. et al. Meas. J. Int. Meas. Confed. 121, 122–126 (2018). [2] Bachhuka, A. et al. Sensors (Switzerland) 19, 1–8 (2019). [3] Hangarge, R. V. et al. ChemistrySelect 2, 11487–11491 (2017).

Authors : A. Romanenko(1), Z. Kerner(1), E. Agocs(1), J. Renkó(2), B. Kalas(1), L. Peter(3), T. Novotny(1), E. Perez-Feró(1), A. Bonyár(4), Z. Hózer(1), P. Petrik(1)
Affiliations : (1)Centre for Energy Research, Konkoly-Thege Miklós Str. 29-33, 1121 Budapest, Hungary (2)Department of Materials Science and Engineering, Budapest University of Technology and Economics, Bertalan Lajos Str. 7, 1111 Budapest, Hungary (3)Wigner Research Centre for Physics, Konkoly-Thege Miklós Str. 29-33, 1121 Budapest, Hungary (4)Department of Electronics Technology, Budapest University of Technology and Economics, Egry József Str. 18, 1111 Budapest, Hungary

Resume : In situ optical configurations and evaluation models were developed for the ellipsometric monitoring of layer formation on metal surfaces. The surface processes can be monitored in a home-made environmental cell by a commercial ellipsometer in the wavelength range of 190-1690 nm at multiple angles of incidence during heat treatment in controlled atmosphere at elevated temperatures up 600 °C. The cell is based on a glass tube that supports focusing (down to a diameter of approximately 0.3 mm) and mapping along the axis of the tube. Processes during liquid flow can be monitored in a different cell construction that also supports focusing and mapping in a limited wavelength range and angles of incidence. The optical models require proper reference dielectric functions and advanced structural models that take into account the interface layers and vertical inhomogeneities. Since the optical configurations are capable of fast monitoring, complex kinetic models of the layer formation process were developed based on the large amount of time-dependent raw data and evaluated model parameters. The surface processes investigated using the new cells include the oxidation and Beraha type color etching of steel and zirconium surfaces.

Authors : Yves Ménesguen, Marie-Christine Lépy
Affiliations : CEA, LIST, Laboratoire National Henri Becquerel (LNE-LNHB), F-91191 Gif-sur-Yvette Cedex, France

Resume : Combining Grazing Incidence X-Ray Fluorescence (GIXRF) and X-Ray Reflectometry (XRR) is gaining increasing interest for the accurate and precise characterization of innovative materials with structures at the nanometer scale. CASTOR is a goniometer dedicated to this technique, which is currently used on the METROLOGIE beamline of the SOLEIL Synchrotron [1]. CASTOR can be installed on both branches of the beamline: the XUV branch (45 eV – 1.9 keV) and the hard X-ray branch (3 – 35 keV) giving access to analyses over a large energy range. It is equipped with calibrated photodiodes to acquire the reflected (or transmitted) X-ray beam and a silicon drift detector (SDD) to record the fluorescence spectra. The photodiodes were accurately calibrated using an electrical substitution cryogenic radiometer and the SDD was calibrated using the SOLEX lab-source. CASTOR is also equipped with a heating module, allowing to perform combined analysis of thin films under a range of temperatures up to 300°C. The fluorescence spectra recorded at grazing angles during a GIXRF experiment are analyzed with the PyMCA or COLEGRAM [2] softwares. The experimental data of both the XRR and GIXRF acquistions are analyzed simultaneously with a Mathematica® program in order to derive the parameters of interest such as the layer thicknesses, roughness, composition, density. We will give examples of recent combined analysis performed on some new materials. [1] Y. Ménesguen, B. Boyer, H. Rotella, J. Lubeck, J.Weser, B. Beckhoff, D. Grötzsch, B. Kanngießer, A. Novikova, E. Nolot and M.-C. Lépy, X-Ray Spectrometry, 46, 303-308 (2017). [2] H. Ruellan, M.-C. Lépy, M. Etcheverry, J. Plagnard, J. Morel, Nuclear Instruments and Methods in Physics Research Section A, Volume 369, 651-656 (1996)

Authors : D.A. Koyuda1, L.A. Osminkina2, S.S. Titova1, U.A. Tsurikova2, O.A. Chuvenkova1, E.V. Parinova1, R.G. Chumakov3, A.M. Lebedev3, S.Yu. Turishchev1
Affiliations : 1 Voronezh State University, 394018, Universitetskaya pl.1, Voronezh, Russia 2 Lomonosov Moscow State University, Faculty of Physics, Leninskie Gory, 1 ,2, 119991 Moscow, Russia 3 National Research Center "Kurchatov Institute", 123182, Akademika Kurchatova pl. 1, Moscow, Russia

Resume : Porous silicon-based nanoparticles (PSi NPs) exhibit good biodegradability properties and are currently quite promising objects for potentially wide application in various biomedical usage, including theranostic applications, antibacterial and antiviral therapy, etc. The drying process and surface pretreatment strongly affect the dissolution rate of PSi NPs in model fluids and living cells. Two types of PSi NPs were obtained: subjected to air drying (AD-PSi NPs) or freeze drying (FD-PSi NPs). AD- and FD-PSi NPs were 1-10 µm agglomerates of 100-nm PSi particles according to the SEM images. Highly intensive synchrotron radiation of Kurchatov synchrotron was used to study the specificity of electronic structure, phase composition and local atomic surrounding specificity of AD- and FD-PSi NPs. X-ray Absorption Near Edge Structure and X-ray Photoelectron spectroscopy were used as analytical techniques. The analysis of the surface physical and chemical state of AD- and FD-Psi powders based on synchrotron data obtained showed, that the freeze-drying process prevents the deep oxidation of the surface of silicon nanocrystals. The results obtained indicate a significant effect of drying processes on the surface properties of PSi NPs, which is important for their long-term storage and further use as therapeutic agents. The study was supported by Russian Science Foundation (Project 19-72-20180).

Authors : Yves Kayser1, Beatrix Pollakowski-Herrmann1, Philipp Hönicke1, Carmen Friese2, Stefan Seeger2, and Burkhard Beckhoff1
Affiliations : 1 Physikalisch-Technische Bundesanstalt, PTB, 10587, Berlin, Germany 2 Federal Institute for Materials Research and Testing BAM, 12489 Berlin, Germany.

Resume : The physical and chemical analysis of aerosols using reliable and physically traceable methods is of importance for a thorough investigation of airborne particles in order to support a better understanding of their origin and impact on health and climate effects. Within the AEROMET [1] project the aim of PTB?s X-ray spectrometry group is to develop and establish traceable and reliable X-ray methods to measure the elemental mass deposition per unit area and the elemental composition of particulate matter supported by a flat substrate. The approach used does not require any reference material or specific sample preparation. During a field campaign in Budapest, Hungary airborne particles were sampled using cascade impactors and deposited on substrates suitable for TXRF analysis. A selection of the samples collected and monitored during the field campaigns has been reinvestigated using reference-free X-ray spectrometry with the aim to cross-validate results from mobile TXRF instrumentation used on-site. A mapping of the collected samples was required due to the smaller spot size, hence smaller investigated area when using synchrotron radiation. A reference-free quantification of the total mass of the deposited material could be carried out and the results allow for a validation of the quantitative results reported from the field campaign which is imporant in view of the qualification of mobile instrumentation for absolute quantitiative measurements.

Authors : Miroslav Valtr12, David Nečas3, Petr Klapetek12
Affiliations : 1 Department of Nanometrology, Czech Metrology Institute, Okružní 31, 638 00 Brno, Czech Republic; 2 CEITEC, Brno University of Technology, Purkyňova 123, 612 00 Brno, Czech Republic; 3 RG Plasma Technologies, CEITEC, Masaryk University, Kamenice 5, 625 00 Brno, Czech Republic

Resume : Scanning Near-field Optical Microscope (SNOM) is a tool for a non-destructive characterization of samples with very high lateral resolution. The resolution is basically given by an optical fibre aperture and can go well below 100 nm. Hence, the limitation given by the diffraction limit can be overcome. We have modified a commercial SNOM for spectroscopic measurements to provide quantitative results instead of only local contrast. We have combined results from spectroscopic SNOM (sp-SNOM) with results from another tool for an optical characterization, namely a spectroscopic imaging reflectometer, to obtain quantitative results on millimetre-scale ranges with locally enhanced lateral resolution. Reflectance spectra acquired by the sp-SNOM were validated by the imaging reflectometer on overlapping areas and supported by Finite Difference in Time Domain calculations. The optical characterization of different silicon dioxide thin films deposited on silicon substrates was further supported by topography measurements using Atomic Force Microscope.

Authors : *Alessandro Cultrera 1, Félix Raso 2, Olga Kazakova 3, Amaia Zurutuza 4, Elena Taboada 5, Norbert Fabricius 6, Andrey Kretinin 7, Alexandra Fabricius 8, and Luca Callegaro 1.
Affiliations : 1 INRIM Istituto Nazionale di Ricerca Metrologica, strada delle Cacce, 91, 10135, Torino, Italy 2 CEM Centro Español de Metrología, Calle del Alfar, 2, 28760 Tres Cantos, Madrid, Spain 3 NPL National Physical Laboratory, Hampton Rd, Teddington TW11 0LW, United Kingdom 4 das-Nano, Poligono Industrial Talluntxe II, Calle M, 10, 31192 Tajonar, Navarra, Spain 5 Graphenea, Mikeletegi Pasealekua, 83, 20009 Donostia, Gipuzkoa, Spain 6 ISC International Standards Consulting, Rubensweg 11, D-32584 Löhne, Germany 7 Uom University of Manchester, Oxford Rd, Manchester M13 9PL, United Kingdom 8 VDE Association for Electrical, Electronic and Information Technologies Stresemannallee 15 60596 Frankfurt am Main Germany

Resume : The GRACE project (2017-2020) [1] aims to an accurate approach to the electrical characterisation of graphene, through the development and comparison of both contact and non-contact methods, with traceability to the electrical SI units. The GRACE consortium is also collaborating with standardization bodies, i.e. International Electrotechnical Commission, to develop new technical specifications that will enable the industry to harmonize the quality of the graphene-based future electronic products. Within the GRACE project we developed validated electrical characterisation protocols specifically for graphene; the investigated methods were both contact and non-contact techniques. Chemical vapour deposited (CVD) graphene samples were produced and circulated among the partners during the project in order to test, on each sample, more than one of the above-cited characterisation methods and compare the measurements outcome. The results of this intercomparison allowed to understand how to meaningfully implement different methods, and the gained experience is now being collected in two Good Practice Guides, that will be presented at this Conference. The GRACE Good Practice Guides will be then published as open access documents on the project website [2] in June 2020. [1] EMPIR 16NRM01 GRACE --- Developing electrical characterisation methods for future graphene electronics. [2] Online:

Authors : I. Vorona1, V. Nosenko1,2, V. Golub3, S. Okulov1, O. Melnichuk4, O.Marie5, X. Portier6, L. Khomenkova1,2, N. Korsunska1
Affiliations : 1) V. Lashkaryov Institute of Semiconductor Physics of NAS of Ukraine, 45 pr. Nauky, 03028 Kyiv, Ukraine; 2) National University «Kyiv-Mohyla Academy», 2 Skovorody str., 04070 Kyiv, Ukraine; 3) Institute of Magnetism of NAS of Ukraine and MES of Ukraine, 36-b Vernadsky blvd., 03142 Kyiv, Ukraine; 4) Mykola Gogol State University of Nizhyn, 2 Hrafska Str., Nizhyn 16600, Ukraine; 5) LCS, UMR 6506, ENSICAEN, Normandie Université, 6 Boulevard Maréchal Juin, Caen 14050, France; 6) CIMAP, CEA, UMR 6252, ENSICAEN, Normandie Université, 6 Boulevard Maréchal Juin, Caen 14050, France

Resume : Cu-doped Y-stabilized ZrO2 (Cu-YSZ) nanopowders calcined at T=800-1100°C were studied by electron paramagnetic resonance (EPR), photoluminescence (PL), diffused reflectance and transmission electron microscopy (TEM) methods. It was found that X- and Q-bands EPR spectra contain broad signal and a set of narrow lines caused by Cu doping. When calcination temperature rises, the broad line contribution decreases, while that of narrow lines increases. Diffuse reflectance and TEM studies showed Cu segregation to the grain surface being accompanied by tetragonal-to-monoclinic phase transformation and appearance of specific green-yellow PL emission. This PL was the most intense in the powders calcined at T=1000°C. The concentration of EPR centres responsible for narrow lines was found to be 1020 centres/g for these powders. Simulations of EPR spectra allowed determining for the first time the parameters of narrow lines as follows: S=1/2, I=3/2, gx=2.021, gy=2.026, gz=2.168, Axx~40*10-4 cm-4, Ayy~35*10-4 cm-4, Azz~186*10-4 cm-4, Axz~10*10-4 cm-4, Ayz~5*10-4 cm-4 for the 63Cu isotope. The analysis of EPR data shows that this centre corresponds to CuZr2+ ions situated in monoclinic ZrO2 lattice. The comparison of EPR, PL and PL excitation spectra leads to the conclusion that this centre participates in green-yellow PL emission that is excited through light absorption by oxygen vacancies.

Authors : C. L. Hapenciuc*(1), I. Ungureanu(1), T. Borca-Tasciuc(2), I. N. Mihailescu(1)
Affiliations : (1) National Institute for Lasers Plasma and Radiation Physics, Romania (2) Rensselaer Polytechnic Institute, USA

Resume : The Wollaston probe used in the last decades in AFM for high resolution thermal conductivity measurement of thin films is not commercialized anymore but the idea behind it can still be exploited for building non-AFM probes. In this work one present preliminary results regarding a new experimental method based on a 50 microns diameter, hand fabricated, hot-probe of Pt90/10Rh alloy which is used to measure the Seebeck coefficient of thin films deposited on glass substrates. Compared with classical methods for measuring Seebeck coefficient based on heater-heat sink ensemble deposited on film surface instrumented with thermocouples, heated metallic rods with built-in thermocouples or microfabricated structures the proposed method provides simplicity in implementation, 50-100 microns spatial resolution, it eliminates the need of large area samples, is fast, reliable and low cost. A thermal model for heat transfer in the probe and to the sample is developed in order to find out the temperature distribution in the probe. The model showed that the ratio of the probe temperature rise in the contact point and average temperature rise is basically independent on electrical current through the probe and film thermal properties. This issue can be used to measure the Seebeck coefficient of the sample within 10% precision. Moreover, the contact radius and thermal contact resistance does not necessary to be known but only the pairs which are fitting the probe thermal resistance in contact with the film-substrate ensemble. This is a great simplification compared with the AFM based hot probe methods which determines these two parameters priori by calibration of two substrates with known thermal conductivity. The method is validated by measuring using the proposed method the Seebeck coefficient on three reference samples with known thermoelectric power. After validation, the method is intended to be used to measure the Seebeck coefficient of nanocrystalline BixSb2-x Te3, x=0, 0.15, 0.25, 0.35, 0.45, 0.55 thin films, of 85nm thickness, deposited by CVD on glass. The results will be compared with data from literature in order to assess their performance for thermoelectric applications.

Authors : A. DJEBAILI 1*; Y. BOUZAHER 1; Z. SKANDERI 2; Ilhem. R. KRIBA 1; A. LAKHZOUM 3
Affiliations : 1 Laboratory of chemistry and environmental chemistry - University of Batna 1- Algeria 2 Institute of Hygiene and Industrial Safety- University of Batna 2- Algeria 3 Faculty of Sciences- Department of Biology - University of Batna 2- Algeria

Resume : With the aim of finding an interpretation for the isomerization reaction of icosadeca-ene by quantum methods, we have studied a series of three molecules giving the following results:  The studied segments (C20H20, C20H10F10, C20H10Cl8, C20H10Br8 and C20H10I8) are very stable. This stability is justified by the HOMO-LUMO found energy gap. However, examination of the stability of several conformations shows that the trans conformer is more stable than the cis conformer in the general assembly.  According to the study of different reaction profiles, we noticed that the size and nature of the dopant plays a very important role on the evolution of the activation energy.  From the obtained values of the activation energy, we find that the speed constants of the isomerization reaction are in the order: kC20H22 >> k C20H10F10 >> k C20H10Cl10 >> k C20H10Br10 >> k C20H10I10  The search for intermediate products during the transition Cis-Trans shows that the geometric parameters (angles and dihedral angles) are the most varied settings, this remark has been observed in the case of substituted and non-substituted icosadeca-ene.  The methods of calculations performed in this work are the Ab-initio and DFT methods, with the bases (6-31G, 3-21G **). All these calculations are performed with the Hyperchem software, where parameters obtained are in a closer order to those obtained with the Gaussian 03W software  Examination of different molecules obtained during the Cis-Trans isomerization reaction shows that the total energy of the resulting intermediate product is of the order of -10487.05 eV, corresponding to a 0.87eV activation energy (23.67 kcal / mol).  With the same HF method (6-31G and 3-21 G**), a close geometry was obtained for the intermediate product in the isomerization reaction with a total energy of 0.93 eV (25.30 kcal/mole), which shows that the different values of the activation energy obtained by the HF and DFT methods at the 6-31G level can be compared to those obtained by Ito, Montaner and Bernier. Keywords: Ab-initio; DFT; kinetics; isomerisation; substituted icosadeca-ene

Authors : S. Turishchev1, E. Parinova1, E. Kaniukov2, D. Koyuda1, I. Ledeneva1, V. Sivakov3
Affiliations : 1 - Voronezh State University, Voronezh, Russia. 2 - Centre of the NAS of Belarus, Minsk, Belarus. 3 - Leibniz Institute of Photonic Technologies, Jena, Germany.

Resume : Copper nanostructures (CuNSs) with highly developed surface are potentially perspective functional material for biosensoric application as plasmon-active surfaces for amplification of the Raman scattering signal. Swift heavy ion track technology has been used for the pre-patterning of surfaces for self-organized localized CuNSs growth in porous matrix. Wet-chemical electroless approach for the localized formation of the CuNSs in pores have been applied. According to scanning electron microscopy data, observed tracks in the silica matrix have been partially filled by two types of copper nanocrystals with the grain dimensions of 10 nm and 70 nm as mean sizes. The samples with different pores filling degree have been investigated. First type of surfaces is related to the partly filled pores by Cu and the second type to overfilled pores with spherical copper caps formation on a top. For a careful and detailed analysis of the observed surface atomic and electronic structure as well as physico-chemical state the X-ray Absorption Near Edge Structure (XANES) using large-scale facilities at BESSY II synchrotron storage ring at HZB Berlin have been used. Noticeable changes of electronic structure and phase composition caused by transformation of crystal sizes and filling degree have been detected. The detected local copper and oxygen atomic surrounding reconstruction allowed us to establish a validity for used proposed technique for controlled formation of SERS sensitive surfaces.

Authors : Streeck, C.*(1), Unterumsberger, R.(1), Hönicke, P.(1), Heikkinen, I.(2), Savin, H.(2), Nolot, E. (3) & Beckhoff, B.(1).
Affiliations : (1) PTB, Physikalisch-Technische Bundesanstalt, X-ray Spectrometry, Germany (2) Aalto University, Department of Electronics and Nanoengineering, Finland (3) CEA-Leti, Laboratoire d'electronique des technologies de l'information, France

Resume : To address the challenges associated with energy generation, storage and transfer in the 21st century, innovations in the field of advanced thin film materials need to be transferred as directly as possible into the production process to ensure a fast lane of technological developments. Complex thin films have to be accurately manufactured with respect to their spatial and elemental composition, interface properties and thicknesses. The reliable analyses of these properties is important in the development and production of advanced thin films. Synchrotron radiation-based X-ray spectrometric methods as Grazing Incidence X-Ray Fluorescence (GIXRF) and Near-Edge X-ray Absorption Spectroscopy (NEXAFS) allow for the variation of the analytical sensitivity, and selectivity needed to effectively reveal the spatial, elemental, and chemical specimen parameters of layers down to the nanometre range. By using radiometrically calibrated instrumentation and knowledge on atomic fundamental parameters a reliable and non-destructive characterization of layer stacks with respect to their mass deposition is possible without using any calibration sample or reference materials. For this purpose, the PTB operates fully characterized X-ray beamlines at the electron storage ring for synchrotron radiation at BESSY II in Berlin. In this work, differently tempered nano layers of AlOx prepared by atomic layer deposition and different mixtures of TiN and WN were characterized.

Authors : A. DJEBAILI 1*; Y. BOUZAHER 1; Z. SKANDERI 2; Ilhem. R. KRIBA 1; A. LAKHZOUM 3
Affiliations : 1 Laboratory of chemistry and environmental chemistry - University of Batna 1- Algeria 2 Institute of Hygiene and Industrial Safety- University of Batna 2- Algeria 3 Faculty of Sciences- Department of Biology - University of Batna 2- Algeria

Resume : In this study, we used quantum chemistry calculations in order to determine some kinetic parameters of the isomerization reaction of the substituted icosadeca-ene. The studied molecules are: (C20H20, C20H10F10, C20H10Cl8, C20H10Br8 and C20H10I8) Cis and Trans. One of the adopted ways to access these parameters (activation energy, rate constant, etc ...) is looking for the transition state that is based on the exploration of intermediaries during the passage of Cis-Trans isomerization process. The study of a ten molecules series gives the following results: * The trans conformer is more stable than the Cis. * The activation energy changes very greatly depending on the size and nature of the substituent according to the reaction profile. * The constants of the isomerization reaction rates are in the following order: kC20H22 >> k C20H10F10 >> k C20H10Cl10 >>k C20H10Br10 >> k C20H10I10. * The geometrical parameters vary considerably according to intermediate products The calculation methods are DFT (TD-B3LYP) and Ab-initio methods at STO-3G*. Keywords: substituted icosadeca-ene, kinetics; isomerisation, HF (AM1+PM6), DFT

Authors : A. Andalouci.*(1), I. Hinkov.(2), Y. Roussigné.(1), S. Farhat.(1) and S.M. Chérif.(1).
Affiliations : (1) Université Sorbonne Paris Nord, Laboratoire des Sciences des Procédés et des Matériaux, LSPM, CNRS, UPR 3407, F-93430, Villetaneuse, France (2) Département de Génie Chimique, Université de Technologie Chimique et de Métallurgique, 8 Boulevard St. Kliment Ohridski, 1756 Sofia, Bulgaria

Resume : The remarkable properties of metallic nanoparticles supported on a substrate reside in their individual nanoscale features as well as in their collective behaviour as an assembly. Therefore, the control of their overall design is of great interest. In this work, we present the fabrication process and the characterization tools of stabilized cobalt nanoparticles (Co NPs) produced by plasma assisted solid state dewetting of sub 3 nm cobalt films deposited on TiSiN supports. Such process reveals to be a promising and non-expensive approach as compared with patterning. The model of dewetting process is analysed from kinetic and thermodynamic points of views. Vibrating sample magnetometry (VSM) and Brillouin light scattering (BLS) techniques were used to investigate both static and dynamic magnetic properties of Co NPs. Ordered arrays of Co NPs with densities up to (4.10^11 NP/cm2) were synthesized. Their shape, size and density were tuned mainly by dewetting parameters and initial Co film thickness. VSM measurements showed relatively high coercivity values depending on Co NPs arrays design, and have been discussed within the frame of magnetic anisotropy introduced by a small deviation to sphericity of the NPs. BLS measurements revealed an unusual reversed Stokes/anti-Stokes height asymmetry, introduced by nanostructuring in comparison to the native layer, revealing that such assembly of NPs behaves as an effective magneto-optical material with tunable properties.

Authors : Diane Eichert*, Laura Borgese**
Affiliations : *ELETTRA – Sincrotrone Trieste, Area Science Park, 34149 Basovizza, Trieste, Italy; **INSTM and Chemistry for Technologies Laboratory, Department of Mechanical and Industrial Engineering, University of Brescia, via Branze 38, 25123 Brescia, Italy

Resume : The COST Action CA 18130 "European Network for Chemical Elemental Analysis by Total Reflection X-Ray Fluorescence" acronym ENFORCE-TXRF (, aims to coordinate research and building capacity in the field of elemental analysis by total reflection X-ray fluorescence spectroscopy (TXRF) in order to develop and assess new tools, protocols, methodologies, and instrumentation for screening and accurate determination of elemental presences and concentrations. The elements targeted are ranging from toxic elements to health, to metal contamination on nanostructured materials or Si wafers. Such analysis may have tremendous repercussions in quality control practices, or in establishing regulatory policy. This Action constitutes an infrastructure for scientific exchange and collaboration to enhance technical standards, and to advance measurement science. This fosters new research activities and allows to combine the various partners’ related expertise in chemistry, physics, life science and engineering. This network will provide the tools to maximize European competitiveness in forming talented scientists, supporting new capabilities that improve research innovation, productivity, standardisation, and quality. ENFORCE-TXRF is opened to all interested in contributing in TXRF field of research, worldwide ( Acknowledgment: Abstract based upon work from COST Action CA18130 supported by COST (European Cooperation in Science and Technology)

Authors : F. Mechachti1, A. Lakhzoum2, A. Djebaili1*
Affiliations : 1 Laboratory of chemistry and environmental chemistry L.C.C.E - University of Batna 1- Algeria 2 Faculty of Biology. University of Batna 2- Algeria.

Resume : The results obtained through the optimization of molecules gave us the different distances and angles according to the methods and bases applied with a C2v symmetry. We were able to determine the total energies, the energy gap ΔE (HOMO-LUMO) of the four conformers trans-transoid; trans-cisoid; cis-transoid; cis-cisoid. (the semi empirical AM1+PM6 at 6-31G and 3-21G** levels) and finally a comprehensive analysis on the topological charges. The analysis of the results show that for the eight molecules, the trans-transoid conformer is energetically very stable compared to the cis-cisoid one, this stability is confirmed by the obtained values for the total energy. The increase in the stability energy leads to a less important Homo-Lumo energy gap. The analysis of the optimized geometrical parameters of the twelve molecules using the AM1 and PM6 methods, are in agreement with the experimental structures characterized by X-ray diffraction. Finally, we were able to determine the reaction profiles of the Cis-Trans isomerization reactions of the hexadecaocta-ene in the gas phase, and to calculate the activation energy (Ea), as well as the diagrams of energies E (eV) based on the coordinates of the isomerization reaction of its molecules, and molar absorption according to energy calculated by the method HF at 6-31G and 3-21G** levels. Thus we have to determine the Spectrum IR of all the molecules by (AM1) and PM6. Keywords: substituted hexadecaocta-ene, semi empirical, HF (AM1+PM6),

Authors : Alina Zoladek-Lemanczyk (1), Lidija Matjacic(1), Filipe Richheimer(1), George Koutsourakis(1), Sebastian Wood(1), Ian Gilmore(1) and Fernando Castro(1)
Affiliations : (1) National Physical Laboratory, UK

Resume : Hybrid organic-inorganic perovskites are a promising material for thin-film solar cells, combining the advantages of high charge-carrier mobility and strong optical absorption to achieve remarkable efficiencies together with the low-temperature and low-cost processability. However, their practical utility remains uncertain due to the notoriously short operation lifetime. Efforts to overcome this challenge are frustrated by the complexity of the degradation mechanisms and the difficulty of obtaining reproducible results. There is an outstanding need for reliable techniques to probe the degradation mechanisms through detailed nano-scale characterisation of chemical changes and their impact on optoelectronic properties. In this study, a well-defined wedge cross section through a complete perovskite device stack was prepared by a secondary ion sputtering. The wedge was imaged with the 3D OrbiSIMS instrument to resolve the chemistry of the layers in the device, then the devices were transferred under vacuum (to prevent contamination of the freshly exposed surfaces) into a glovebox for correlative imaging by Atomic Force Microscopy (AFM) and Photoluminescence (PL) imaging. This approach offers combined chemical and optoelectronic measurements of the different components in a working perovskite solar cell. Comparison between a pristine and degraded devices reveal the interdiffusion of layers and chemical changes related to the degradation of nanoscale optoelectronic performance.

Authors : Wansleben,M.(1), Zech,C.(2), Streeck, C.*(2), Weser,J.(2), Genzel,C. (1), Beckhoff, B.(2) & Mainz,R.(1)
Affiliations : (1) HZB, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Germany (2) PTB, Physikalisch-Technische Bundesanstalt, X-ray Spectrometry, Germany

Resume : Liquid-metal jet X-ray sources promise to deliver high photon fluxes, which are unprecedented for laboratory based X-ray sources, because the regenerating liquid-metal anode is less sensitive to damage caused by an increased electron beam power density. For some quantitative X-ray analysis techniques, knowledge of the absolute photon flux is needed. However, a precise experimental determination of the photon flux of high-performance X-ray sources is challenging, because a direct measurement results in significant dead time losses in the detector or could even harm the detector. Indirect determinations rely on data base values of attenuation or scattering cross sections leading to large uncertainties. In this study we present an experimental determination of the photon flux of a liquid-metal jet X-ray source by means of elastic and inelastic photon scattering. Our approach allows for referencing the unpolarised output radiation of the liquid-metal jet X-ray source to polarized synchrotron radiation in a simple setup. Absolute photon fluxes per solid angle are presented with a detailed uncertainty budget for the characteristic emission lines of Ga Ka and In Ka for two different acceleration voltages of the X-ray source. (DOI: 10.1039/c9ja00127a)

Authors : O. Melnichuk1, L. Melnichuk1, Ye. Venger2, M.-P. Chauvat3, X. Portier3, N. Korsunska2, L. Khomenkova2,4
Affiliations : 1)Mykola Gogol State University of Nizhyn, 2 Hrafska Str., Nizhyn 16600, Ukraine; 2)V. Lashkaryov Institute of Semiconductor Physics of NAS of Ukraine, 45 Pr. Nauky, 03650 Kyiv, Ukraine; 3)CIMAP/ENSICAEN/UNICAEN/CEA/CNRS, 6 Blvd Marechal Juin, 14000 Caen, France; 4)National University “Kyiv-Mohyla Academy”, 2 Skovorody str., Kyiv 04070, Ukraine

Resume : The effect of plasmon-phonon interaction is investigated for ZnO films grown on p-type Si substrates by radio frequency magnetron sputtering. ZnO target was sputtered in pure argon or mixed argon-oxygen plasma. The film properties were investigated using atomic force microscopy, spectroscopic ellipsometry and specular Fourier-transformed infrared reflection followed by the dispersion analysis of theoretical and experimental values for the reflection coefficient. The results indicate that the films grown in argon plasma had larger surface roughness that increases with deposition time. Contrary to this, the films produced in argon-oxygen plasma were found to be denser and smoother. They demonstrate also an abrupt absorption band-gap edge that was explained by the lower number of native defects (such as Zn interstitials) contributed to the film conductivity. Analysis of specular infrared reflection spectra revealed the influence of plasmon of the substrate on the plasmon-phonon interaction in ZnO film. The films grown in pure argon plasma demonstrated higher concentration of free carriers and smaller their mobility in comparison with corresponding parameters of the films grown in argon-oxygen mixed plasma. The findings of this work demonstrate an application of this approach for the prediction of the properties of textured thin films.

Authors : R. Unterumsberger1, A. Gross2, H. Stosnach2, P. Hönicke1 and B. Beckhoff1
Affiliations : 1Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany; 2Bruker Nano GmbH, Am Studio 2D, 12489 Berlin, Germany

Resume : Total reflection X-ray fluorescence (TXRF) analysis became one of the most powerful and cost competitive techniques for surface chemical and trace element analyses [1]. By using calibrated instrumentation and the fundamental parameter approach [2], reference-free quantification can be performed [3]. When monochromatic synchrotron radiation in the soft X-ray range is used, even light elements can be quantified. Since more than 10 years PTB has an ISO 17025 compatible Quality Management procedure for reference-free quantification of elemental mass deposition [4]. With varying incident angle for the excitation radiation (Grazing Incidence X-Ray Fluorescence - GIXRF), more information about the respective elements like the sequence of layers [5, 6], or even information about the related chemical binding states of the sample structure [7,8,9] can be revealed when using tunable excitation radiation. But, so far the access to calibrated instrumentation and synchrotron radiation is limited which leads to the usage of reference samples. Here, the characterization of reference µl-droplets has been investigated with respect to the lateral spreading [10] and absolute mass deposition. The lateral spreading can affect the effective solid angle of detection and influence the X-ray Standing Wave (XSW) field due to shadowing effects for small incident angles. This work shows the strength of reference-free quantification with GIXRF analysis by means of suitable samples and illustrates the importance of well-characterized reference samples for TXRF applications. [1] Total-Reflection X-Ray Fluorescence Analysis and Related Methods, Eds. R. Klockenkämper and A. von Bohlen, John Wiley & Sons (2015) [2] M. Mantler et al., Quantitative Analysis, in Handbook of Practical X-Ray Fluorescence Analysis, Springer, 2006, pp. 309–410 [3] B. Beckhoff., J. Anal. At. Spectrom. (2008) 23, 845 – 853 [4] B. Beckhoff et al., Anal. Chem. (2007) 79, 7873-7882 [5] R. Unterumsberger et al., Anal. Chem. (2011) 83, 8623-8628 [6] C. Streeck et al., Appl. Phys. Lett. (2013) 103, 113904 [7] V. Soltwisch et al., Nanoscale (2018) 10, 6177-6185 [8] P.M. Dietrich et al., Anal. Chem. (2015) 87(19), 10117-10124 [9] T. Fischer et al., Anal. Chem. (2015) 87(5), 2685-2692 [10] M. Müller et al., Solid State Phenomena (2012) 187, 291-294

Authors : Diane Eichert
Affiliations : ELETTRA – Sincrotrone Trieste, Area Science Park, 34149 Basovizza, Trieste, Italy

Resume : Total Reflection X-ray Fluorescence (TXRF) offers some appealing micro-analytical properties for the biomedical and biochemical communities, in constant need of sensitive screening and quantification methods for characterizing the effect and/or fate of novel nanomaterials or drugs designed to be used in the clinics. By its nature surface sensitive, allowing a simultaneous determination of the elemental compositions with detection limits in the low picogram range, TXRF is presenting an interesting alternative to primary methods such as Inductively coupled plasma (ICP) based techniques, which rely on tedious sample preparation procedures and potentially suffer from low recovery rates. Used thoroughly, TXRF analysis may help in 1) classifying samples, their origins or interdependencies by recognition of the elemental information, 2) providing a quantitative analysis of the elements even in complex matrices, 3) predicting the properties or effects of the elemental occurrence in a system via quantitative structure-activity-function relationships, or even 4) monitoring processes and status by the development or knowledge of a sensor e.g. elemental occurrence or threshold. TXRF analytical potential will be illustrated in pharmaceutics, by assessing elemental impurities in Active Pharmaceutical Ingredients (API) and carriers, and in nanomedicine, by quantifying nanoparticles cellular delivery and uptake, and probing bio-labelled molecules and their substrates for bio-platforms.

Authors : Roland Mainz1, Pascal Becker1, Justus Just2, Jose Marquez1, Rafael Müller1, Hampus Näsström1, Sebastian Risse1, Helena Stange1, Malte Wansleben1, Manuela Klaus1, Christoph Genzel1
Affiliations : 1) Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, 14109 Berlin, Germany; 2) MAX IV Laboratory, Lund University, PO Box 118, SE-22100 Lund, Sweden

Resume : Phase transitions and microstructure changes play a crucial role during the fabrication of functional materials such as solar cell films or battery electrodes. Moreover, knowledge of the stability ranges of crystalline phases or decay processes in humid atmosphere are essential to judge on the suitability of a material for a specific task. Real-time and in-situ X-ray analysis has proven as indispensable method to gain these insights in compound materials. However, to analyze the dynamics of rapid phase transitions and microstructure changes, sufficient time resolution is a prerequisite. Synchrotron radiation, which provides high photon fluxes and thus enables high time resolutions, have the drawback of low availability. This imposes a major limitation for time-consuming studies. To solve this limitation, we have developed a laboratory setup based on a high-flux liquid-metal-jet X-ray source, polycapillary optics, a 2D-detector for X-ray diffraction (XRD) and an SDD detector for simultaneous X-ray fluorescence analysis (XRF). In this contribution, we demonstrate the suitability of this setup for time-resolved in-situ/in-operando XRD and XRF studies in the lab. We utilize these capabilities to study phase transformations and decay processes in inorganic perovskite absorber films for solar cells exposed to humid air as well as in Li-S batteries during multiple charge/discharge cycling.

Authors : Gaurav Lole, Vladimir Roddatis and Christian Jooss*
Affiliations : Institut für Materialphysik, Georg-August-Universität Göttingen, Germany.

Resume : Understanding the active state of electrocatalysts in operando conditions is essential for improved understanding of mechanism and rational design of efficient and stable systems. Environmental transmission electron microscopy (ETEM) can contribute to this topic since it offers a comprehensive study of interactions of catalyst surfaces in controlled environment of water, in different reactive and non-reactive gases1, in electric potentials2 and at atomic column resolution. Here, we study the atomic dynamics of mobile manganese (Mn) adatoms at single crystalline edges of La1-xSrxMnO3 (x=0.4) (LSMO) manganites in high vacuum (HV), reactive environment (H2O, O2) and in inert atmosphere (N2). LSMO shows reversible Mn adatom mobility on top of stable A-site cations. To study atomic dynamics in ETEM, the preparation of ultrathin electron transparent TEM lamella with minimum preparation induced defects and avoiding any catalytically relevant impurities is required. Considerably modifying the widely used FIB lift-out technique by using a photoresist protection layer and attaching the TEM lamella to Cu grid by using Cu redeposition technique results in Pt-free high quality samples. Loss of oxygen due to ion milling can be compensated by an electron beam induced oxidation in O2 environment in the ETEM, leading to a well-defined highly crystalline surface structure3. The structure of LSMO (001) surface was then studied in different ambient with atomic column resolution with aberration corrected high-resolution TEM. Remarkably, columns of moving Mn adatoms have been identified on top of stable La/SrO terminated surfaces. It is observed that the Mn adatom hopping on the (001) surface of LSMO in a thin liquid H2O layer is 20 times higher than in high vacuum or gases, such as O2 and N2. At step edges, a strong reduction of the Mn adatom hopping rate in H2O from >4s-1 to r <1.4 s-1 is observed due to the presence of an Erich Schwoebel barrier. Our studies shed light on the role of Mn adatoms on manganite perovskite interfaces to H2O for the oxygen evolution catalysis in electrochemical water oxidation. It implies that partial solvation of active Mn surface adatoms might be essential for the understanding of the active state of Mn-O based catalyst and opens new perspectives in atomic scale design of efficient and stable electrode surfaces for OER. References 1. Ch. Jooss S. Mildner, M. Beleggia, D. Mierwaldt, V. Roddatis in “Controlled Atmosphere Transmission Electron Microscopy - Principles and Practice”, edited by Jakob Birkedal Wagner and Thomas Willum Hansen, Springer 2016 2. S. Mildner, M. Beleggia, D. Mierwaldt, Th. W. Hansen, J. B. Wagner, S. Yazdi, T. Kasama, J. Ciston, Y. Zhu, and Ch. Jooss, Environmental TEM Study of Electron Beam Induced Electrochemistry of Pr0.64Ca0.36MnO3 Catalysts for Oxygen Evolution J. Phys. Chem. C, 119 (2015) 5301–5310. 3. V Roddatis, G Lole and Ch Jooss, In situ preparation of Pr1-xCaxMnO3 and La1-xSrxMnO3 catalyst surface for high resolution environmental transmission electron microscopy. Catalysts (2019). doi:10.3390/catal9090751

Authors : Fabian Kraft, Kimmo Mustonen, Morris Weimerskirch, Tristan Nagy, Toma Susi
Affiliations : Physics of Nanostructured Materials University of Vienna, Physics of Nanostructured Materials University of Vienna, Physics of Nanostructured Materials University of Vienna, Department of Physical Chemistry University of Vienna, Physics of Nanostructured Materials University of Vienna,

Resume : In high-resolution electron microscopy of 2D materials, atomically clean sample surfaces are crucial. Ex-situ cleaning methods one established cause damage and often leave a layer of contamination on the sample. Pre-situ cleaning via heat and laser irradiation in the same vacuum system as an aberration-corrected scanning transmission microscope (STEM) have been shown causing less damage and atomically clean surfaces [1]. We developed a free-space, far-field laser system with external focusing optics for irradiating the sample in-situ while observed in STEM, sharing the same environmental decoupling. Furthermore, the optical return path is used for VIS spectroscopy. In-situ systems with near-field focusing optics using integrated pierced parabolic mirrors have been used for photon-induced electron energy loss/gain specroscopy (EELS/EEGS) an cathode luminescence (CL) studies [2]. In contrast, our modular approach uses an available view-port and leaves the rest of the setup intact. In this work, we elaborate on it's design, focussing optics and operation. [1] [2]

Authors : Osan, J.(1), Kayser, Y.*(2), Pollakowski-Hermann, B.(2), Török, S.(1) & Beckhoff, B.(2)
Affiliations : (1)Centre for Energy Research, Budapest, Hungary (2)Physikalisch-Technische Bundesanstalt, Berlin, Germany

Resume : Health effects caused by particulate air pollution are of high concern. Although the number concentration can be determined routinely by scanning mobility particle sizers, the toxicity of particles depends on their elemental composition and chemical speciation. Total-reflection X-ray fluorescence (TXRF) and near-edge X-ray absorption fine structure (NEXAFS) spectrometry are promising techniques for this task. Size fractionated aerosol samples were collected in Budapest (Hungary) and Cassino (Italy) using a cascade impactor on Si wafers in the size range of 70 nm to 600 nm. The effect of particle load on TXRF quantification and NEXAFS speciation of carbon and nitrogen was tested at the synchrotron radiation facility BESSY II (Berlin, Germany) in the soft X-ray regime. It was found that the X-ray standing wave field is disturbed for high particulate loads requiring corrections for the quantification. NEXAFS results indicated the presence of organic carbon besides the dominating elemental carbon at both sites. Absorption effects are important for samples which are highly loaded with soot and organic particles. Nitrogen was found as ammonium and organic-bound, however radiation damage has to be carefully considered. This work was supported by European Structural and Investment Funds jointly financed by the European Commission and the Hungarian Government through grant no. VEKOP-2.3.2-16-2016-00011 and by the EMPIR initiative of the European Union's Horizon 2020 program, through grant agreement 16ENV07 AEROMET.

Authors : L. Khomenkova1,2, D. Lehninger3, V. Yukhymchuk1, X. Portier4, P. Petrik5, F. Gourbilleau4, N. Korsunska1, J. Heitmann3
Affiliations : 1) V. Lashkaryov Institute of Semiconductor Physics, 45 Pr. Nauki, Kyiv 03028, Ukraine; 2) National University “Kyiv-Mohyla Academy”, 2 Skovorody str., Kyiv 04070, Ukraine; 3) Institute of Applied Physics, TU Bergakademie, Freiberg, Germany; 4) CIMAP, Normandie Univ, ENSICAEN, UNICAEN, CEA, CNRS, Caen, France; 5) Institute for Technical Physics and Materials Science (MFA), Center for Energy Research (EK), Hungarian Academy of Sciences (MTA), Budapest, Hungary

Resume : The impact of isovalent dopants on optical and structural properties of HfO2 matrix attracts significant attention due to the unique optical and electrical properties of such materials. In the present work, the effect of annealing temperature on the properties of Ge-doped HfO2 thin films is investigated by spectroscopic ellipsometry, Raman scattering, XRD and TEM methods. The films were grown by radio-frequency top-down magnetron co-sputtering of pure Ge and HfO2 space-apart targets. The Ge content in the films was varied in the range 0-60 at % via power density applied on Ge target. Besides, pure Ge and pure HfO2 films were prepared for comparison. The samples were annealed in at T=300–1000 °C for 30 s in a nitrogen atmosphere. As-deposited homogeneous Ge-HfO2 films were found to be amorphous contrary to pure HfO2 films. This fact confirms that Ge incorporation stabilizes the amorphous HfO2 phase that was found to be stable up to T=600 °C. The T increase up to 800°C results in the formation of pure Ge nanocrystallites as well as tetragonal HfO2 grains. Further T rise favors considerable Ge out-diffusion from the films followed by the appearance of the monoclinic HfO2 phase. At the same time, no Si presence was revealed in the film volume testifying on the stability of these films in direct contact with Si substrate. The mechanism of the film phase transformation is discussed.

Authors : B. Postolnyi
Affiliations : IFIMUP - The Institute of Physics for Advanced Materials, Nanotechnology and Photonics of the University of Porto

Resume : Modern complex research dedicated to fabrication and characterisation of novel materials requires a broad list of costly equipment which is in many cases not available at the same research unit, especially true for academic institutions or scientific centres with poor budget. In such conditions, researchers either are looking for collaboration to perform required experiments, or waiting/applying for financial support, or even just giving up with that potentially promising research idea. If such collaboration contacts are existed, very often they are placed far away in other countries or continents, which means a time and money consuming procedure to carry out a visit and research or even just send samples for analysis. Young scientists and early career investigators are even more sensitive for such problems since their own scientific network may be not well grown yet. The development of everywhere reaching online database of material research facilities will help in described situations as well as in many other cases. Research units of any type may also benefit from placing equipment in the database as a tool to increase their visibility and to find new collaborations and projects. First studies of opinions and expectations from the database have been performed among material science researchers and research units’ management. Basic principles and functionality will be presented.

Authors : Bogdan Postolnyi, Alexander Pogrebnjak, Joao Pedro Araujo
Affiliations : IFIMUP, Faculty of Sciences of the University of Porto, Porto, Portugal; Sumy State University, Sumy, Ukraine

Resume : Multi-Layered Nanocomposite CrN/MoN Thin Films fabricated by magnetron sputtering and by vacuum arc evaporation of cathodes have been studied be several types of X-ray based characterisation techniques. Elemental composition of the surface was studied by energy-dispersive X-ray spectroscopy (EDS) and wavelength-dispersive X-ray spectroscopy (WDS). Additionally, the elemental characterisation has been performed by means of X-ray fluorescence (XRF) and total reflection X-ray fluorescence (TXRF) to compare results and reliability of such techniques, which are not commonly used for hard metal nitride thin films investigation. Multilayer structure of coatings was studied by EDS elemental depth profiling and EDS elemental mapping. Micro- and nanostructure of CrN/MoN coatings was studied by X-ray diffraction (XRD) techniques. Particularly, X-ray reflectivity (XRR) to measure thickness of individual layers and period multi-layered thin films and X-ray diffraction in various geometries to study phase composition, lattice parameters and preferential orientation. As CrN and MoN films have similar crystal structure and lattice parameters, a conventional θ/2θ scan gives broadened peaks on overlapped XRD pattern of two CrN and Mo2N cubic phases. To distinguish individual layers grazing incidence XRD (GIXRD) approach was employed when by selecting a fixed incidence angle in a low range it is possible to get XRD pattern limited by a certain X-ray penetration depth. Based on GIXRD and sin2ψ method the residual stresses and strain for individual layers have been evaluated. In-plane XRD experiments have been performed for analyses of diffraction planes oriented normal to the surface with control of incidence angle to get information from different layers of the multi-layered CrN/MoN coatings. It was shown that many X-ray based characterisation techniques are very helpful and adequate to analyse micro-, nanostructure and elemental composition of multi-layered CrN/MoN thin films: EDS, WDS, XRD, TXRF, XRD, XRR, GIXRD, in-plane XRD.

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08:45 Plenary Session 2    
Surface characterisation : Marie-Christine Lépy and Yves Kayser
Authors : Gabriella Borionetti,Cristina Sanna
Affiliations : MEMC Electronic Materials SpA a GlobalWafers Company Viale Gerzi,31 28100 Novara Italy

Resume : Electronic Devices Industry is known to have been driven since its early stages by a continuous technological effort of miniaturization because of the dual need of manufacturing cost reduction through integration and offer to the user market of smaller and smaller electronic applications, more efficient, versatile and differentiable. Silicon wafer manufacturers have been forced to provide larger size silicon wafers, 300mm diameter is nowadays covering more than 50% of the total market, with dimension and density of residual defects moving from microns to nanometers, from ppt to ppq or even less. In this context, proper choice of measurement technique and set up which can guarantee measurement reliability to detect a given defect and provide information of its distribution inside the wafer is mandatory. It has to cope the need to control material quality in a range more frequently close to the measurement detection limit and the need to improve the associated manufacturing process capabilities. The paper intends to propose a few examples in the area of crystallographic/morphological defects and chemical impurities on silicon wafers, reviewing the defect analysis approach inside a manufacturing environment. Discussion will also involve the final product certification data reporting which tends to convey in a very synthetic format the whole measurement and control process.

Authors : Diane Eichert
Affiliations : ELETTRA – Sincrotrone Trieste, Area Science Park, 34149 Basovizza, Trieste, Italy

Resume : The value of elemental analysis depends upon the level of confidence that can be placed in the results. Adopting good laboratory practices, standard operating procedures, metrology and quality principles help in maximizing the reliability of the results. TXRF is one of the most impressive analytical technique providing spectral signatures of materials that unravel their elemental composition and surface contamination. Within seconds and limited sample preparation, a qualitative characterization can be obtained, whereas thorough and quantitative information requires a full experimental design approach. Also, tiny variations in the experimental conditions may cause fine spectral differences that may be difficult to identify, but affect tremendously the validity of the results. Per se and despite its apparent versatility and ease-of-use, many issues remain opened in TXRF analysis. These are lying from sample preparation procedures and requirements (e.g. very flat substrate as Si wafer, nanostructures deposited on wafer), instrumentation and experimental conditions to data analysis and standardization, and prevent the spread of TXRF in chemical and material analytical communities. To counteract, some European initiatives (e.g. CA 18130 are reflecting on TXRF current challenges and defining a realistic road map establishing the correct conditions for TXRF analysis and its domains of applicability, while joining chemical and physical traceability approaches.

Authors : E. Parinova 1, S. Turishchev 1, D. Koyuda 1, R. Ovsyannikov 2, J. Fedotova 3, E. Streltsov 3, F. Kronast 2, D. Marchenko 2, A. Fedotov 3
Affiliations : 1 Voronezh State University - Voronezh (Russian Federation) 2 Helmholtz Zentrum Berlin - Berlin (Germany) 3 Belarusian State University - Minsk (Belarus)

Resume : Arrays of Ni rods embedded in a dielectric SiO2 matrix with the enhanced tunable magnetoresistance effect can be a perspective basis for modern electronic applications or devices. Swift heavy ion tracks with different radiation doses were applied followed by chemical etching of SiO2 layers aimed at pores formation. Subsequent electrochemical filling of pores by Ni allowed to form arrays of rods with different geometry and surface distribution. A complex of synchrotron radiation based techniques were applied to characterize the morphology, electronic structure and local Ni, Si and O atoms surrounding at surface and interfaces of given structures. Real microspot imaging PhotoEmission Electron Microscopy technique were applied for the first time to investigate simultaneously morphology, magnetic remanence and electronic structure at microscopic level. Low nickel oxides residuals were found at the surface between metallic Ni rods while no interatomic interactions were detected even if rods concentration led to small surface Ni islands formation. Further increase of rods amount (island coverage) may lead to low silicide formation at the developed interfaces. The proposed technological approach allows to effectively form magnetically patterned Ni rods arrays having relatively sharp interface boundaries with SiO2 wide gap matrix. The study was supported by the RFBR (project No. 18-32-01046 mol_a).

Authors : Smekhova, A.*(1), List-Kratovchil, E.J.W.(1,2), Streeck, C.(3), Richter, M.(3) & Vollmer, A.(1)
Affiliations : (1) Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein-Str. 15, 12489, Berlin, Germany (2) Institut für Physik, Institut für Chemie & IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 6, 12489 Berlin, Germany (3) Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany

Resume : X-rays from brilliant synchrotron sources are widely exploited in materials research already for decades providing the unique possibilities to probe structural, electronic and magnetic properties of different types of materials and their dynamic characteristics in the element-specific way with an appropriate time resolution. Further development of synchrotron facilities worldwide offers new scientific opportunities for frontier studies related to novel materials and their functionality as well as further progress in the improvement of measurement techniques and detection procedures. BESSY III designed by Helmholtz-Zentrum Berlin and its strategic partners will be a globally competitive synchrotron radiation large-scale user facility in the field of XUV, soft and tender X-rays for research and industry. A particular aspect of Materials Metrology within the BESSY III project is accompanied by the Physikalisch-Technische Bundesanstalt, Germany's National Metrology Institute. The role of Materials Metrology in studies of new functional materials, e.g. for quantum information technology, effective solar cells manufacture, batteries improvement, smart coatings, etc., is currently under active discussions. The implementation of established procedures of standardized and validated measurements with SI-units traceable quantities as well as advanced instrumentation will provide BESSY III user community more possibilities for trustworthy and reliable studies.

Authors : E.V. Egorov, V.K. Egorov
Affiliations : IMT RAS, Financial University under the government Russian Federation, IRE RAS; IMT RAS

Resume : The Rutherford backscattering spectroscopy (RBS) is the best method of host element depth concentration profile determination in thin films and material surface layers. For the elements contamination analysis it can be added by the Particle Induced X-ray Emission (PIXE) and Total X-ray Reflection Analysis (TXRF) experimental methods. TXRF measurements are more effective for trace analysis of elements characterized by high energy of characteristic radiation yield and present data about element composition of surface layer with thickness 3-5 nm with high sensitivity. The X-ray planar waveguide-resonator (PXWR) including into the TXRF spectrometer setup allows to decrease the contamination detection limits on 3 orders. PIXE method is very perspective for light element analysis but it allows to obtain volume contamination concentration data. PXWR including into the PIXE measurements setup allows to receive new high effective experimental method for surface layer element diagnostics: TXRF-PIXE. Complex application of methods allows to get total picture about object element composition without it destruction. Suitable experimental data are discussed.

Energy materials characterisation : Sascha Nowak and Burkhard Beckhoff
Authors : Sebastian Risse (a), Rafael Müller (a), Ben Kent (a), Eneli Härk (a), Ingo Manke (b), André Hilger (b), Nikolay Kardjilov (b) and Matthias Ballauff (a,c)
Affiliations : (a) Helmholtz-Zentrum Berlin, Institute of Soft Matter and Functional Materials, Hahn-Meitner-Platz 1, 14109 Berlin, Germany (b) Helmholtz-Zentrum Berlin, Institute of Applied Materials, Hahn-Meitner Platz 1, 14109 Berlin, Germany (c) Institute of Physics, Humboldt-University Berlin, Unter den Linden 6, 10099 Berlin, Germany

Resume : Lithium/sulfur (Li/S) batteries have a fivefold higher theoretical gravimetric energy density (2680 Wh/kg) than state-of-the-art lithium ion batteries [1]. However, the strong capacity fading with increasing cycle number is still a major obstacle to a broad technical utilization despite decades of research. Operando techniques [2] are very suitable tools to gain mechanistic understanding of degradation processes. Especially the simultaneous combination of several independent measurements (multidimensional) while the Li/S cell is in operation allows deep insights into the degradation mechanisms and provides further mechanistic understanding of the complex Li/S chemistry. Here we present results of a novel setup where up to five independent measurements are simultaneously performed. Electrochemical impedance spectroscopy (EIS), UV-vis spectroscopy, temperature measurement and X-ray imaging [3] or neutron small angle scattering were performed over several cycles while the cell was galvanostically or potentiostatically charged and discharged. Structural changes on the macroscopic and microscopic scale can be correlated to characteristic signals in the EIS, charge-discharge curve and UV-vis spectroscopy. [1] X. Fan, W. Sun, F. Meng, A. Xing, J. Liu, Advanced chemical strategies for lithium-sulfur batteries: A review, Green Energy Environ. 3 (2017) 2–19. doi:10.1016/j.gee.2017.08.002. [2] J. Tan, D. Liu, X. Xu, L. Mai, In situ/operando characterization techniques for rechargeable lithium-sulfur batteries: a review, Nanoscale. (2017) 19001–19016. doi:10.1039/C7NR06819K. [3] S. Risse, C.J. Jafta, Y. Yang, N. Kardjilov, A. Hilger, I. Manke, M. Ballauff, Multidimensional operando analysis of macroscopic structure evolution in lithium sulfur cells by X-ray radiography, Phys. Chem. Chem. Phys. 18 (2016) 10630–10636. doi:10.1039/C6CP01020B.

Authors : Giorgia Greco, Giuseppe Antonio Elia, Paul H. Kamm, Francisco Garcìa-Moreno, Simone Raoux, Robert Hahn
Affiliations : 1 Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Hahn-Meitner-Platz 1, D-14109 Berlin, Germany. 2 Technische Universität Berlin, Research Center of Microperipheric Technologies, Gustav-Meyer-Allee 25, D-13355 Berlin, Germany. 3 Fraunhofer-Institut für Zuverlässigkeit und Mikrointegration, Gustav-Meyer-Allee 25, D-13355 Berlin, Germany.

Resume : Today Li-ion batteries are the main power source of choice for full and hybrid electric vehicles and portable electronics devices.1,2 However, the use of Li the main global power source for electromobility and grid application is questionable due to limited lithium resources.3 Alternatives to lithium, such as Na, K, Ca, Mg and Al, have attracted great interest in the last years due to the greater abundance of these elements. Among them Al is one of the most abundant metal elements in the Earth's crust and is characterized by an extremely high volumetric capacity of 8040 mA h cm-3, which is four times higher than that of lithium, making it an extreme good candidate to replace Li.3 In this work we propose an operando characterization in terms of X-Ray Diffraction (XRD) combined with X-ray tomography of two full-battery systems based on pyrolytic graphite (PG) and natural graphite (NG) as anodes. Those systems are very similar but show different electrochemical behaviors in terms of reversibility and capacity retention after the first cycle. 1. K. E. Aifantis and S. A. Hackney, in High Energy Density Lithium Batteries, ed. K. E. Aifantis, S. A. Hackney and R. V. Kumar, WILEY-VCH Verlag, Weinheim, 2010, pp. 81–101. 2. D. A. Notter, M. Gauch, R. Widmer, P. Wäger, A. Stamp, R. Zah and H.-J. Althaus, Environ. Sci. Technol., 2010, 44, 6550–6556. 3. G. A. Elia, K. Marquardt, K. Hoeppner, S. Fantini, R. Lin,E. Knipping, W. Peters, J.-F. Drillet, S. Passerini and R. Hahn, Adv. Mater., 2016, 28, 7564–7579.

Authors : Claudia Zech [1] , Olga Grätz [2] , Philipp Hönicke [1] , Yves Kayser [1] , Manfred Stamm [2] , Burkhard Beckhoff [1]
Affiliations : [1] Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany; [2] Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Straße 6, 01069 Dresden, Germany

Resume : Lithium sulfur batteries (Li/S batteries) are promising candidates for batteries in electric vehicles and as stationary energy storage device due to their high specific energy density. The underlying degradation mechanisms are not completely unraveled yet, but it is known that the formation of soluble polysulfides causes capacity fading and limits the cycle life, so that the Li/S battery is not widely commercially used nowadays. For the investigations of the time depended aging mechanism analytical operando methods are needed. In the present work, the use of synchrotron radiation, calibrated instrumentation and the combination of operando NEXAFS (near edge X-ray fine structure) and traceable XRF (X-ray fluorescence analysis) measurements enables the absolute quantification of the mass deposition for sulfur in dissolved polysulfides for the first time. With our reference-free quantification method, no calibration samples have to be used. Moreover, with a new cell design we got access to polysulfides at both electrode sides which lead to the simultaneous investigation of conversion reactions and transport mechanisms and therefore the possibility to evaluate the polysulfides shuttle phenomena. The measurements have been performed over three full charge/discharge cycles. With our experimental set-up, we additionally got access to the change of the average polysulfide chain length which enables a deeper understanding of the capacity fading processes. The presented measurement cells as well as the quantification method can be adopted for other cell chemistries, like lithium ion batteries or even all solid state batteries.

Authors : Artur Braun
Affiliations : EMPA

Resume : Atmospheric oxygen that we live on is the result of a fundamental evolutionary step in photo-synthesis which occurred on Earth 2-3 billion years ago [Biello 2009]. The water oxidation in natural photosystem II accounts for 50% of this oxygen. The man-made analog to this natural process is water oxidation in photoelectrochemical cells - one of the most complex processes in physical chemistry. I will showcase how modern x-ray spectroscopy methods have assisted in the understanding of the molecular processes which occur in natural [Bora 2013, Ralston 2000, Visser 2001] and in man-made "photosystems". A most recent example is the element and orbital specific identification of transient electron holes in iron oxide [Braun 2012], chemical surface intermediates [Bora 2011] and changes in the water molecules in the electrochemical double layer during photoelectrochemical water oxidation [Braun 2016]. I will also demonstrate how the electronic structure evolution is quantitatively paralleled by the electric transport properties of the electrodes during operation. [Biello 2009] The Origin of Oxygen in Earth's Atmosphere. In Scientific American 2009. [Bora 2011] J Phys Chem C 2011, 115:5619-5625. [Bora 2013] J ELECTRON SPECT RELATED PHEN. 2013, 190:93-105. [Braun 2012] J Phys Chem C 2012, 116:16870-16875. [Braun 2016] Catalysis Today 2016, 260:72-81. [Ralston 2000] JACS 2000, 122:10553-10560 [Visser 2001] Journal of the American Chemical Society 2001, 123:7031-7039

12:30 Lunch break    
Dimensional and analytical x-ray nanometrology : Marie-Christine Lépy and Burkhard Beckhoff
Authors : T.P.A. Hase, M. Bowie, S. Harris, D. Rusu, W. Dong and M. Alexe
Affiliations : Department of Physics, University of Warwick, Coventry, CV4 7AL, U.K.

Resume : In the field of ferroelectrics, the heteroepitaxial growth of complex oxides has enabled materials to be created in which the strain and the polarization, electric gradient and elastic energies and be tuned. Competition between these energy terms produces competing ferrotoroidic phases which manifest as structural domains of polar flux-closure topologies, vortices and skyrmionic structures. Superlattices also allow tailoring of the layer parameters to modify the structure-energy relationships. Detailed research efforts are now underway to understand the underpinning physics and explore potential applications. Critical to this effort are detailed structural studies and new metrology pathways to quantify the topologies found. In this presentation we will have explore epitaxial superlattices grown on DyScO3 with ferroelectric PbTiO3 and different spacers; paraelectric insulators (SrTiO3, and TbScO3) and metallic SrRuO3. We observe domain structures that clearly depend on the nature of the spacer layer, the thickness of the ferroelectric layer, the ratio of ferroelectric to spacer layer thickness and the total number of repeats. The parameter space is explored using both laboratory and synchrotron high resolution double axis x-ray diffraction through satellite diffraction arising from the topological states observed. We present a metrology which enables the topologies to be quantified and benchmark our findings using TEM analysis.

Authors : D. Koyuda1, S. Turishchev1, E. Parinova1, D. Nesterov1, A. Ershov2, Yu. Vainer3, T. Kulikova1, E. Zinchenko1, M. Grechkina1, V. Terekhov1
Affiliations : 1 - Voronezh State University, Universitetskaya pl.1, 394018, Voronezh, Russia. 2 - Lobachevsky State University of Nizhni Novgorod, pr. Gagarina 23, 603950, Nizhni Novgorod, Russia. 3 - Institute for Physics of Microstructures, RAS, 7 Akademicheskaya str, Nizhny Novgorod, Russia

Resume : Controlled silicon nanocrystals (nc-Si) formation in dielectric matrix is promising direction for the opto- and nanoelectronic devices development. One of the ways for nanocrystals size control is the formation of the multilayered nanoperiodical structures (MNS) with fixed thicknesses of nanolayers containing Si nanoparticles between nanolayers of different materials (e.g. ZrO2). The redundant Si in the SiO2 matrix can be obtained by annealing of the SiOx films. Another way to form nc-Si can be annealing of amorphous silicon interlayers. MNS were formed by a-SiOx or a-Si and ZrO2 or Al2O3 or SiO2 layer by layer deposition on to Si substrates with few nanometers thickness respectively of each layer type. The formed structures were annealed aimed at photoluminescent Si nanoparticles formation with fixed sizes. MNS were studied by means of electronic structure and local atomic surrounding sensitive XANES spectroscopy and XPS techniques supported by XRD and SEM. A noticeable changes of electronic structure and phase composition caused by transformation of the Si atoms surrounding is shown depending on MNS properties. High temperature annealing do not always lead to Si nanoparticles formation in MNS formed with a-Si interlayers. Effective interaction between MNS silicon/dielectric layers is studied. The highest temperature anneal of 1100 C can lead to complete MNS destruction. Al2O3 is suggested as best dielectric material for nc-Si arrays formation in MNS.

Authors : E. Nolot, Y. Mazel, F. Gaillard, V. Huynh, A. André, C. Scibetta, D. Morel, E. Augendre, E. Rolland, T. Lorne
Affiliations : Univ. Grenoble Alpes, CEA, LETI, F-38000 Grenoble

Resume : We have developed in-fab monitoring strategy for microporous silicon films fabricated by etching 200 mm p-doped (100) silicon wafers in HF-based solutions. We have generated different porous silicon films with porosity in the 50 to 60% range and thickness from 6 to 20 µm. First, high-resolution X-ray diffraction (HR-XRD) permits to quantify the strain inside the porous silicon layer and to assess the influence of the resistivity of the substrate on the uniformity of the crystalline properties at the wafer level. Secondly, spectroscopic ellipsometry (SE) and M-line spectroscopy permit to derive the optical properties of the films in the visible and near-infrared spectral range, and to reveal their variability, amid the wafer set and at the wafer level. We used these optical properties to model the Spectroscopic Reflectometry (SR) and the Fourier Transform Infrared spectroscopy (FTIR) data, in order to provide non-destructive mapping of the film thickness, with spatial resolution from 1 mm (FTIR) down to 20 µm (SR). The comparison with thickness maps obtained by Scanning Electron Microscopy (SEM) demonstrated a 2% (resp. 5%) match between SEM and FTIR (resp. SR) deduced thicknesses. At the end, the combination of HR-XRD and optical analysis, i.e FTIR and SR strategy based on SE and M-line spectroscopy, fits the requirement for fast operator-compatible monitoring of the uniformity of the porous silicon process at the wafer level.

Authors : Vivek Singh*, Jyoti Sinha*, Sushobhan Avasthi*
Affiliations : *Centre for Nano Science and Engineering (CeNSE), Indian Institute of Science, Bangalore, 560012 India

Resume : Cuprous oxide (Cu2O) is a promising material for emerging electronics. Bandgap and defect states estimation of Cu2O film grown by chemical vapor deposition (CVD) technique on SiO2/Si substrate at 600°C was performed in this work using various spectroscopies. XRD and XPS confirmed the phase purity of deposited film. The optical bandgap of Cu2O was 2.35 eV which was calculated from absorption spectroscopy (UV-Vis). Using ultraviolet photoelectron spectroscopy (UPS) and absorption spectroscopy (UV-Vis), the nature of deposited Cu2O was confirmed as a p-type semiconductor. Using UPS, the energy level of the valence band and Fermi level of the intrinsically p-doped Cu2O film were determined as 6.02 eV and 5.62 eV respectively from the vacuum level. The temperature dependence photoluminescence spectra of these films exhibited emission peaks at ~1.4 eV and ~1.72 eV which corresponds to energy states of copper and oxygen vacancies level in the bandgap. Photoluminescence spectra also show a peak at ~2 eV which is due to the relaxation of free excitons to the valance band.

Authors : Jhih-Wei Chen, Chung-Lin Wu, and Chia-Hao Chen
Affiliations : National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan, Department of Physics, National Cheng Kung University,Tainan 70101, Taiwan; Department of Physics, National Cheng Kung University,Tainan 70101, Taiwan, National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan; National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan

Resume : Up to date, most of the size of the van der Waals (vdW) materials and their heterostructures are in the range of several tens of micro-meter square, and because of the monolayer nature, the thicknesses of these systems are mostly within the nano-meter range. With the characteristics of the dimensionality, it is impossible to study the properties of the vdW systems without the help of microscope. Here, we present a synchrotron-radiation based soft X-ray photoelectron microscopy, which utilizing a Fresnel zone plate optics to focus the monochromatic soft X-ray down to 100 nm spot size. By combing the fine spot size and the surface sensitive nature of photoelectron spectroscopy, this system is an ideal platform to study the intrinsic properties of vdW systems. Some of the recent studies regarding the electronic and chemical properties of vdW systems will be presented and discussed.

Authors : Jhonatan Rodriguez-Pereira (1), Raul Zazpe (1,2), Hanna Sopha (1,2), Jan Prikryl (1), Milos Krbal (1), Siowwoon Ng (2), Filip Bures (3), Jan M. Macak (1,2)
Affiliations : (1) Center of Materials and Nanotechnologies, Faculty of Chemical Technology, University of Pardubice, Nam. Cs. Legii 565, 530 02 Pardubice, Czech Republic; (2) Central European Institute of Technology, Brno University of Technology, Purkynova 123, 61200 Pardubice, Czech Republic; (3) Institute of Organic Chemistry and Technology, Faculty of Chemical Technology,University of Pardubice, Studentska 573, 53210 Pardubice, Czech Republic

Resume : The success of graphene opened a door for a new class of chalcogenide materials with unique properties that can be applied in several applications such as the semiconductor technology [1], optoelectronics [2], hydrogen evolution [3], photodegradation of organic dyes [4] or electrodes in Li ion batteries [5]. TMDCs can be prepared by various top-down (e.g. exfoliation) and bottom-up techniques, such as chemical vapor deposition (CVD) and atomic layer deposition (ALD) growth techniques [1]. MoS2, a typical representative of TMDCs, has been widely studied for several applications. Recently, the possibility to employ ALD as a technique to grow MoS2 has been reported. In these works (CH3)2S2 [6] or H2S [7, 8] were used as the S precursor and Mo(CO)6 [6], MoCl5 [7] or Mo(thd)3 [8] as the Mo precursors. Another interesting TMDC is MoSe2 since it possesses a higher electrical conductivity than MoS2 [9, 10]. Recently, we have shown that ALD deposition of MoSe2 [11] or Mo-O-Se [12] using ((CH3)3Si)2Se as the Se precursor and the MoCl5 or Mo(CO)6, respectively, as the Mo precursors is feasible. Since the applications of the aforementioned 2D materials involve chemical and/or electronic processes on the surface, the XPS characterization is a crucial tool to evaluate their quality in terms of the composition. Therefore, this work will focus on the changes of surface chemical state of synthesized MoS2 and MoSe2 by ALD over different substrates (Silicon, Quartz, Titanium and TiO2 nanotubes). Recent results will be presented and discussed. References: [1] A. V. Kolobov, J. Tominaga, Two-Dimensional Transition-Metal, Dichalcogenides. Springer Series in Materials Science, Springer International Publishing AG, Switzerland 2016 [2] B. Radisavljevic, A. Radenovic, J. Brivio, V. Giacometti, A. Kis, Nat. Nanotechnol. 2011, 6, 147. [3] L. Wang, Z. Sofer, J. Luxa, M. Pumera, Adv. Mater. Interfaces 2015, 2, 1500041 [4] Y. Wu, M. Xu, X. Chen, S. Yang, H. Wu, J. Pan, X. Xiong, Nanoscale 2016, 8, 440 [5] D. Ilic, K. Wiesener, W. Schneider, H. Oppermann, G. Krabbes, J.Power Sources 1985, 14, 223 [6] Z. Jin, S.Shin,D.H.Kwon, S. J.Han,Y. S.Min,Nanoscale 2014, 6, 14453. [7] L. K. Tan, B. Liu, J. H. Teng, S. Guo, H. Y. Low, K. P. Loh, Nanoscale 2014, 6, 10584 [8] M. Mattinen et al., Adv. Mater. Interfaces 2017, 4, 1700123. [9] D. Kong, H. Wang, J. J. Cha, M. Pasta, K. J. Koski, J. Yao, Y. Cui, Nano Lett. 2013, 13, 1341. [10] A. Eftekhari, Appl. Mater. Today 2017, 8. [11] M. Krbal et al., Phys. Stat. Sol. RRL, 2018, 12, 1800023 [12] S. Ng et al., Adv. Mater. Interfaces 2017, 1701146.

Authors : Pâmella V. B. Pinho*, Alain Chartier*, Jean-Baptiste Moussy**, Frédéric Miserque*
Affiliations : * DEN – Service de la Corrosion et du Comportement des Matériaux dans leur Environnement (SCCME), CEA Saclay, Université Paris-Saclay ** Service de Physique de l’Etat Condensé (SPEC), CEA, CNRS UMR 3680, Université Paris Saclay, CEA Saclay

Resume : Cr2O3 is a magnetoeletric, antiferromagnet oxide often envisioned for use in future high-performance spintronic devices. A crucial issue toward device application is the enhancement of Cr2O3 operating temperature. Strain engineering may overcome this issue, as the distortion of the CrO6 octahedron affects the single-ion anisotropy through the modulation of the crystal field (CF). Here, the aim is to evaluate CF effects through the lattice relaxation of a-Cr2O3(0001) ultrathin films by analyzing the Cr 2p XPS spectra. Since epitaxial thin films exhibit thickness-dependent XPS line shapes, spectra were acquired at different growth stages of a-Cr2O3 deposited onto a-Al2O3(0001) substrates by molecular beam epitaxy. Then, semiempirical crystal field multiplet calculations were performed to understand the effect of the CF in the redistribution of the spectral lines intensity. Optimization of CF parameters for thick layers shows small splitting of the 3d orbital triplet (t2g into a1 + e). Conversely, optimal CF parameters for first epilayers exhibit large splitting of the t2g along with a significant destabilization of a1 with respect to e orbital. This orbital destabilization is the fingerprint of large in-plane strain imposed by the positive lattice mismatch between Cr2O3 and Al2O3. This comprehensive approach of the XPS spectra is a groundwork for understanding the influence of strain in the local electronic structure, which is essential to fine tune thin films properties.

16:00 Coffee Break    
Dimensional and analytical x-ray nanometrology II : Diane Eichert and Philipp Hönicke
Authors : Dirk Lützenkirchen-Hecht (1), Jan Stötzel (1), Justus Just (2), Oliver Müller (3), Benjamin Bornmann (1), Ronald Frahm (1)
Affiliations : (1) Bergische Universität Wuppertal, Germany; (2) Lund University, Sweden; (3) SLAC National Accelerator Laboratory, USA.

Resume : Quick-EXAFS adds time resolution to X-rays absorption spectroscopy and thus allows to follow dynamic structural changes of matter. This is of particular interest for the in-situ monitoring of nanomaterials synthesis, where e.g. the structure and the growth of nanoparticles in gaseous or liquid environments can be followed on time-scales from sub-seconds to minutes or even hours. While conventional transmission or fluorescence mode EXAFS are capable to investigate bulk materials only, the use of the grazing incidence geometry provides surface sensitivity, thus enabling detailed structural investigations of thin films and surfaces. Here we will discuss dedicated experimental setups and routines used for time-resolved grazing incidence data acquisition and analysis. Case studies will feature in-situ studies during the sputter deposition of different thin film materials. The analysis of the grazing incidence EXAFS data allows to follow thin film growth on time scales of 50 ms, yielding their structure, surface and interface roughness, as well as their chemical composition. In the case of copper, the surface oxidation of the films induced by air exposure was studied for different temperatures, showing a passivation with Cu(I)-oxide layers of some few nm thickness at room temperature, while oxide layers of several 10 nm thickness are formed for temperatures of 150-250 °C. Future prospects of the time-resolved EXAFS techniques for investigations of nanomaterials will be discussed.

Authors : Gilles E. Moehl, and Andrew L. Hector
Affiliations : Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.

Resume : Mesoporous silica films are typically produced by evaporation-induced self assembly (EISA), but vertical alignment of the pores to the substrate is very difficult to achieve. Hexagonal arrays of vertically aligned mesopores can be achieved by electrochemically assisted surfactant assembly (EASA). Under the Advanced Devices by Electroplating EPSRC programme grant (EP/N035437/1) we are working on the integration of nanowire semiconductor structures into electronics, using aligned mesoporous templates as host for the electrodeposition of high quality chalcogenide semiconductors. The self-assembly of a cationic surfactant (typically cetyltrimethylammonium bromide) close to the substrate surface relies on the application of a negative potential to an electronically conductive substrate, but also leads to the formation of spheroidal surface aggregates, limiting the obtainable film thickness to a few hundreds of nm. Grazing incidence small angle X-ray scattering (GISAXS) allows for the non-destructive structural analysis of thin films with high statistical relevance in lateral and vertical direction. In this work, we show the results obtained from in situ GISAXS experiments done during the EASA of silica, following the evolution of the structure formation in real time with sub-second time resolution. From this, suggestions to a more detailed mechanism of formation are made through detailed data analysis.

Authors : (a) Kim von Allmen, (a) Johan Gustafson, (a) Hira Qazilbash, (b) Assunta Vigliante, (b) Peter Wochner
Affiliations : (a) Division of Synchrotron Radiation Research, Lund, Sweden (b) Sirius XRS, Kirchheim unter Teck, Germany

Resume : Surface X-ray diffraction (SXRD) studies are important to determine the 3D structure of single crystal surfaces and surface structures that form in the presence of reactive gases. [1,2] Due to the weak interaction between X-rays and matter, the surface-related diffraction signal is much lower than that of the bulk. Synchrotron radiation is thus used in conventional SXRD studies to get the desired signal to noise ratio. Herein we try to bring this technique from the synchrotron to the lab which makes it possible to prepare beamtimes more efficiently. A SXRD setup was installed at Lund University by Sirius XRS. It is equipped with a Mo microfocus X-ray source (17.6 keV) and a 2D noise-free, hybrid photon counting detector. A specially designed reaction chamber was mounted which allows us to prepare samples by standard surface science techniques and to do catalytic tests at pressures up to 1 atm. By using a sealed tube microfocus X-ray source instead of synchrotron radiation, experiments require longer exposure times and adequate shielding of X-ray photons from diffuse scattering is necessary. After the optimization of these parameters, it was possible to study CO oxidation on different oxides formed on Pt(110) and to successfully determine the active phase. [1] U. Hejral, et al., Phys Rev. B., 96, 2017, 195433. [2] J. Gustafson, et al., Science, 343, 2014, 758.

Authors : Anna Andrle, Philipp Hönicke, Philipp-Immanuel Schneider, Dimitrios Kazazis, Yves Kayser, Martin Hammerschmidt, Sven Burger, Frank Scholze, Burkhard Beckhoff, Victor Soltwisch
Affiliations : Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany; Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany; JCMwave GmbH, Bolivarallee 22, 14050 Berlin, Germany; Paul Scherrer Institut, Forschungsstrasse 111, 5232 Villigen PSI, Switzerland; Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany; JCMwave GmbH, Bolivarallee 22, 14050 Berlin, Germany; JCMwave GmbH, Bolivarallee 22, 14050 Berlin, Germany, Zuse Institute Berlin, Takustrasse 7, 14195 Berlin, Germany; Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany; Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany; Physikalisch-Technische Bundesanstalt, Abbestrasse 2-12, 10587 Berlin, Germany

Resume : A reliable and non-destructive characterization of the material composition and dimensional parameters of the nanostructures is needed for the production of the current and next generation semiconductor devices. A metrology technique based on grazing incidence X-ray fluorescence measurements is applied here to lamellar nanoscale gratings made of Si3N4 and SiO2. The X-ray standing wave field, which arises due to interference between the incident and the reflected radiation, is used as a nanoscale sensor in this technique. Depending on the elemental composition and dimensional parameters of the nanostructures, distinct angular dependent fluorescence signals are observed when the sample is rotated with respect to the incident radiation. The X-ray standing wave field can be calculated with a finite element Maxwell solver in order to model the experimental data using a parameterized model of the nanostructure. This modeling allows to derive the spatial distribution of elements and the geometric shape with sub nanometer resolution. The computational effort of such a reconstruction can be very big depending on the dimensional parameters of the nanostructure. With a Bayesian optimization approach this effort can be kept at a reasonable level. We demonstrate the characterization of different lamellar Si3N4 and SiO2 grating structures.

Authors : Wallez, G.* (1,2,3), Gonzalez, V. (4,5), Cotte, M. (2,6), van Loon, A. (4,7), de Nolf, W. (6), Eveno, M. (1,3), Keune, K. (4,8), Noble, P. (4), Dik, J. (5)
Affiliations : (1) Institut de Recherche de Chimie Paris, France; (2) Sorbonne Université, Paris, France; (3) Centre de Recherche et de Restauration des Musées de France, Paris, France; (4) Rijksmuseum, Amsterdam, The Netherlands; (5) Delft University of Technology, The Netherlands; (6) European Synchrotron Radiation Facility, Grenoble, France; (7) Mauritshuis, The Hague, The Netherlands; (8) University of Amsterdam, The Netherlands

Resume : Rembrandt van Rijn (1606-1669) is renowned for his innovations in painting materials and techniques, like his impasto process which consists in laying thick white paint protrusions to enhance light reflection. Like most artists of his time, Rembrandt used lead white pigments, that is, mixtures of cerussite PbCO3 (C) and hydrocerussite Pb3(CO3)2(OH)2 (HC) obtained by lead corrosion. Microsamples collected in the impastos of six Rembrandt’s masterpieces of Dutch and French museums were analyzed by synchrotron diffraction on ESRF beamlines ID13 (μ-XRD mapping) and ID22 (hi-res XRD) to determine the composition and microstructure of the pigments by Rietveld analysis and infer the preparation processes. The most striking feature is the systematic presence of plumbonacrite Pb5(CO3)3O(OH)2 (PN), a rare mineral, never observed heretofore in ancient paintings, only stable in highly alkaline media and indistinguishable from HC by spectroscopic methods. Rembrandt’s PN, 20-40 w% of the pigment, consists in nanoplatelets about 10 nm thick. XRD mapping reveals PN aggregates that account for a neofomation process in the paint. In line with the XRD measurements and lab-made mock-ups, the most probable explanation is the use by the Master of high amounts of lead oxide as a siccative for the impasto oil. Indeed, basic PbO in excess is highly reactive towards acid C, yielding PN, as confirmed by the unusual low C ratio associated. V. Gonzalez et al., Angew. Chem. Int. Ed. 58 (2019) 5619-5622.

Authors : O. Taché, B. Durand, E. Barruet, F. Gobeaux, B. R. Pauw, A. Thill
Affiliations : LIONS - NIMBE CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France ; LIONS - NIMBE CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France ; LIONS - NIMBE CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France ; LIONS - NIMBE CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France ; Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany; LIONS - NIMBE CEA, CNRS, Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France

Resume : Spherical silica nanoparticles are developed to be used as reference material for monomodal and bimodal dispersion. The manufacturing quality of these materials is essential and often is not perfectly controlled. Improving this fabrication requires a fine understanding of synthesis, coupled with the expertise of in-situ or ex-situ analysis methods. This constitutes a new challenge for the analysis: it is indeed a question of determining not only average characteristics (Size, chemical composition, and shape...) but also the concentration and the distribution over the population studied. Small-Angle X-ray Scattering allows very precise measurements that can be directly linked to the metric system (metrological traceability). We developed a laboratory instrument dedicated to the in-situ characterization of nanoparticles during the synthesis, which enables fast measurements and the monitoring of the parameters. Measurement protocols and software processing chains (i.e. size distribution) are also combined & optimized.

18:30 AWARD CEREMONY followed by SOCIAL EVENT    
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Joint session with Symposium A: Metrology of photovoltaic compounds : Alex Redinger and Roland Mainz
Authors : Claudia S. Schnohr
Affiliations : Felix Bloch Institute for Solid State Physics, University of Leipzig, Germany

Resume : Thin film solar cells based on Cu(In,Ga)(Se,S)2 have reached a record efficiency of 23.3%. Similar to other complex semiconductors, the properties of this material can be specifically tailored by tuning its composition and stoichiometry. According to theoretical calculations, the local arrangements of the atoms play an important role in determining the material properties. Atomic scale structural parameters, such as element-specific bond lengths and bond length variations, can be determined by synchrotron-based X-ray absorption spectroscopy. For Cu(In,Ga)Se2, these element-specific bond lengths differ significantly from each other and correspond to severe anion displacements, which contribute to the nonlinear change of the band gap energy with In/(In+Ga) ratio [1]. The bond length variation, and hence the bulk disorder on the subnanometer scale, in co-evaporated thin films does not depend on the In/(In+Ga) ratio, the Cu history or the alkali treatment, but it shows a clear and reversible correlation with the Cu content [2]. A strong increase of local disorder is also observed for Cu(In,Ga)3Se5 and Cu(In,Ga)5Se8 [3]. Furthermore, the element-specific bond lengths slightly increase with decreasing Cu content although the lattice constants shrink, highlighting the remarkable differences between atomic scale structure and crystallographic structure in CIGS and its alloys. [1] Appl. Phys. Rev. 2, 031304 (2015). [2] Acta Mater. 153, 8 (2018). [3] J. Alloys. Comp. 774, 803 (2019).

Authors : Alex Redinger
Affiliations : Scanning Probe Microscopy Laboratory, Department of Physics and Materials Science, University of Luxembourg

Resume : The optoelectronic properties of grain boundaries (GBs) in polycrystalline materials for PV applications are of outmost interest since they may limit the ultimate device performance. Kelvin Probe Force Microscopy (KPFM) is one of the most powerful measurement techniques to investigate GBs due to the ability to probe band bending, and thereby the accumulation of localized charges with nanometre resolution. Over the last years, different KPFM measurement modes have been developed, which allow to perform measurements in air, inert gas or vacuum with varying degrees of resolution and constrains. In this contribution, I will show how different measurement modes affect the GB contrast and how environmental conditions influence the results. I will show that amplitude modulation KPFM in air and in vacuum, which is by far the most common KPFM mode to study GBs, is not suitable to measure band bending since the roughness of the samples leads to a strong crosstalk between the electrical signal and the topography. I will show how these artefacts can be identified and how they are strongly reduced if frequency modulation KPFM is used instead. Furthermore, samples prior to air exposure will be compared to samples after air expose. The most important conclusion is that air exposure is irreversibly changing the electrostatic landscape and thus needs to be prevented by all means. I will show examples for Cu(In,Ga)Se2 and methylammonium lead iodide and present a literature overview discussing how the published results need to be interpreted in view of present work.

Authors : Tiarnan A.S. Doherty1, Andrew J. Winchester2, Stuart Macpherson1, Duncan N. Johnstone3, Vivek Pareek2, Elizabeth M. Tennyson1, Sofiia Kosar2, Felix U. Kosasih3, Miguel Anaya1, Mojtaba Abdi-Jalebi1, Zahra Andaji-Garmaroudi1, E Laine Wong2, Julien Madéo2, Yu-Hsien Chiang1, Ji-Sang Park4, Young-Kwang Jung5, Christopher E. Petoukhoff2, Giorgio Divitini3, Michael K. L. Man2, Caterina Ducati3, Aron Walsh4,5, Paul A. Midgley3, Keshav Dani2, Samuel D. Stranks1
Affiliations : 1Cavendish Laboratory, University of Cambridge, 2Femtosecond Spectroscopy Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa 3Department of Materials Science and Metallurgy, University of Cambridge, 4Department of Materials, Imperial College London, 5Department of Materials Science and Engineering, Yonsei University, Korea

Resume : Metal halide perovskite (MHP) materials exhibit exceptional performance characteristics for low-cost optoelectronic applications. Though widely considered defect tolerant materials, perovskites still exhibit a sizeable density of deep sub-gap non-radiative trap states, which create local variations in photoluminescence [doi: 10.1126/science.aaa5333] that fundamentally limit device performance. These trap states have also been associated with light-induced halide segregation in mixed halide perovskite compositions [doi: 10.1021/acsenergylett.8b02002] and local strain [doi:10.1039/C8EE02751J], both of which can detrimentally impact device stability. The origin and distribution of these trap states remains unknown as multiple, complimentary multi-modal techniques are required to probe their location and surrounding structure and composition and MHPs damage rapidly under the electron beam. Understanding the nature of these traps will be critical to ultimately eliminate losses and yield devices operating at their theoretical performance limits with optimal stability. In this talk, we outline a low dose, multi – technique framework to reveal the structural origins of non-radiative recombination sites in (Cs0.05FA0.78MA0.17)Pb(I0.83Br0.17)3 thin films[Accepted, Nature]. By combining scanning electron diffraction and energy dispersive X-ray spectroscopy, with photoemission electron microscopy (PEEM) measurements we reveal that nanoscale trap clusters are distributed non-homogenously across the surface of high performing perovskite films and that there are distinct structural and compositional fingerprints associated with the generation of these detrimental sites.

Authors : Konrad Ritter(1)*, Maurizio Ritzer(2), Cora Preiß(2), Charles Hages(3), Rakesh Agrawal(4), Claudia S. Schnohr(1)
Affiliations : (1)Felix-Bloch-Institut für Festkörperphysik, Universität Leipzig, Linnéstraße 5, 04103 Leipzig, Germany (2)Institut für Festkörperphysik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany (3)Department of Chemical Engineering, University of Florida, Gainesville, FL 32611, USA (4)Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN 47907, USA

Resume : Alloying of kesterite type materials allows material properties like the band gap energy to be tuned directly by the ratio of certain elements. Furthermore, Ge shows great potential in reducing problems associated with the Sn in Cu2ZnSn(S,Se)4 and Ag is discussed as a partial replacement of Cu in the context of Cu-Zn disorder. As shown for many semiconductor materials, alloying changes the local atomic scale structure and thereby directly influences the band gap energy [1]. To probe the local atomic structure, low temperature Extended X-ray Fine Structure Spectroscopy (EXAFS) measurements were performed. Analysis of this kind of data has successfully allowed to connect experimental bond lengths and anion positions with band gap energy for Cu2Zn(Ge,Sn)Se4 powder samples [2] and is now applied to technologically relevant (Ag,Cu)2ZnSn(Se,S)4 and Cu2Zn(Ge,Sn)(Se,S)4 thin films. Ab initio theoretical calculations yield the band gap change with the experimentally acquired structural parameters. This allows an estimation of the part of the band gap bowing, that results from a change of the structural parameters. [1] C. S. Schnohr, Appl. Phys. Rev. 2, 031304 (2015). [2] K. Ritter et al., to be submitted

Authors : Usiobo O.J. (1), Kanda H. (2), Audinot J-N. (1), Nazeeruddin M.K. (2), and, Wirtz T. (1)
Affiliations : (1) Advanced Instrumentation for Ion Nano-Analytics (AINA), Materials Science and Technology Department, Luxembourg Institute of Science and Technology, Luxembourg (2) Ecole Polytechnique Fédérale de Lausanne, Switzerland * Usiobo, O.J.

Resume : Solar power has a major role in the crucial transition to low carbon power. Perovskite solar cells, in particular, are a great photovoltaic alternative as they exhibit excellent energy harvesting abilities and do not require energy-intensive manufacturing techniques. While poor stability during scale-up of perovskite photovoltaics limits their widespread commercial use, the key is the relationship between the microstructure and properties. Thus, an analytical strategy is necessary for resolving the microstructure at the nanoscale to efficiently tune the perovskite properties beyond the current state of the art. We have developed a magnetic sector Secondary Ion Mass Spectrometer (SIMS) and coupled it to a Helium Ion Microscope (HIM). Owing to this, we combine the best of both worlds; the high lateral resolution in secondary electron imaging of the HIM with the high detection limit of our internally developed SIMS instrument. In SIMS mode, we are able to detect elements in the full mass range with a lateral resolution below 15 nm. The SIMS data can be correlated with sub-nm resolution secondary electron images. We will show several analytical studies completed with HIM-SIMS, among them, a cross-sectional chemical map of a multi-cation based perovskite device where different thin films at the nanoscale can be distinguished. HIM-SIMS is a versatile and powerful technique for the improved understanding of the impact of microstructure on photovoltaic performance and stability.

Authors : Mario Ochoa, Stephan Brunken, Galo Torres Sevilla, Shih-Chi Yang, Marek Chrapa, Patrick Reinhard, Ayodhya N. Tiwari, Romain Carron
Affiliations : 1. Laboratory for Thin Films and Photovoltaics, Empa-Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, CH-8600 Duebendorf, Switzerland. 2. Flisom AG, Gewerbestrasse 16, CH-8155 Niederhasli, Switzerland

Resume : Lateral inhomogeneities in material properties arise in Cu(In,Ga)Se2 solar cells from fabrication processes, growth conditions and its polycrystalline nature. An essential parameter defining the quality of the material is the carrier lifetime, which directly influences the open circuit voltage (Voc) and the performance of the devices. Time resolved photoluminescence (TRPL) is typically used to characterize the carrier lifetime. The low injection regime is the preferred measurement condition but is challenging to achieve experimentally, especially for mapping measurements, due to the difficulty to obtain a sufficient signal-to-noise-ratio. Achieving such conditions allows for a better understanding of the possible Voc limitations at standard test conditions due to lateral inhomogeneities. In this contribution, we evaluate a wide-field illumination microscopy technique to achieve low injection conditions. We will present the spatial distribution of carrier lifetime at both large and small scale (cm-μm) for different Cu(In,Ga)Se2 absorbers with different materials. The intensity and lifetime maps obtained revealed significant inhomogeneities with strong non-Gaussian distributions. An assessment of the impact of such distributions and its correlation to Voc and solar cell performance will be presented.

Authors : Hisham Aboulfadl, Jonatan Holmér, Jan Keller, Mattias Thuvander, Eva Olsson, Marika Edoff
Affiliations : Hisham Aboulfadl; Mattias Thuvander Division of Microstructural Physics, Chalmers University of Technology, 41296 Göteborg, Sweden Jonatan Holmér; Eva Olsson Eva Olsson group, Chalmers University of Technology, 41296 Göteborg, Sweden Jan Keller; Marika Edoff Division of Solid-State Electronics, Uppsala University, 75236 Uppsala, Sweden

Resume : Photovoltaic devices using quinary (Ag,Cu)(In,Ga)Se2 (ACIGSe) alloy absorbers are reported to exhibit improved opto-electronic properties when using high-Ga concentrations which is due to a widened band gap compared to Cu(In,Ga)Se2 (CIGSe) [1]. The addition of Ag atoms allows reducing deposition temperatures, which is argued to decrease the intragrain defects in the chalcogenide structure. Alkali metals incorporated in the absorber, are widely-known to have a positive effect on the performance of the corresponding devices, possibly via suppression of recombination effects at interfaces. In CIGSe, alkali metals are commonly reported to segregate at grain boundaries and in ordered vacancy compounds [2]. The solubility of alkali metals is predicted to vary in ACIGSe, hence, investigations using high resolution characterization techniques are required to study the chemistry and microstructure relationships. ACIGSe absorber samples were deposited on soda lime glass (Na-rich) and high-strain point glass (K-rich), respectively, followed by KF-PDT. Transmission Kikuchi diffraction (TKD), glow discharge optical emission spectroscopy (GDOES), electron beam induced current (EBIC) and atom probe tomography (APT) were employed to analyze the structure, the local carrier concentration, as well as the local compositions in the absorber material. The composition in different grains and grain boundaries of the absorber were compared. Correlative microscopy provides here a deeper understanding of the opto-electronic behavior and microstructure. [1] M. Edoff, et al., IEEE J. Photovoltaics. 7 (2017) 1789–1794. [2] A. Stokes, et al., Sci. Rep. 7 (2017) 1–11.

Authors : Leo Choubrac(1), José Márquez Prieto(1), Hannes Hempel(1), Justus Just(2), Taiseer Jokadar(1), Thomas Unold(1)
Affiliations : (1) Helmholtz‐Zentrum Berlin für Materialien und Energie GmbH (2) MAX IV Laboratory, Lund University, P.O. Box 118, SE‐221 00 Lund, Sweden

Resume : Kesterite solar cell conversion efficiency stagnates for a few years due to a low VOC compared to the Schockley-Queisser limit. The losses can be classified into 3 groups: Non-radiative (NR) – related to short minority carriers lifetime, Non-ideal absorptivity (affected by the density of tail states) and device losses (DL – imperfect resistances, interface losses…). NR and NIA losses are the most critical as those arise from absorbers' intrinsic properties, and a bright future for kesterite will not come without a significant reduction in (NIA+NR) losses. To overcome this, numerous strategies, such as doping, alloying, annealing, Sn supply during selenisation have been developed, with limited success. Implementing a new processing strategy have several impacts at the same time, hence requiring additional work of composition and device re-optimization to demonstrate or rebut their beneficial effect. We produced kesterite layers with lateral compositional gradients and used them to explore the effect of various synthesis parameters. Then, high throughput characterization (XRF, Raman, absolute photoluminescence and UV-vis hyperspectral imaging) were performed to extract the NR and NIA VOC losses for a very broad range of composition. As a result, we can conclude on the effects of those parameters on kesterite intrinsic properties with high statistics, for a broad range of composition. Moreover, it minimizes the risk that an improvement of intrinsic properties is masked by a third party phenomenon (drift of optimum composition, reproducibility issue, device-related losses) that could be resolved elsewhere. In particular, we discuss the effect of selenisation conditions and the role of Na and absorber air-annealing on the different losses for a large composition range within the ternary phase diagram.

12:15 Lunch break    
EMPIR projects on nanocharacterisation : Francois Ziade and Thomas Hase
Authors : Eleonora Cara1, Federico Ferrarese Lupi1, Philipp Hönicke2, Yves Kayser2, Samuele Porro3, Fabrizio Pirri3, Katharina Brassat4, Jörg Lindner4, Burkhard Beckhoff2, Natascia De Leo1, Luca Boarino1
Affiliations : 1 Advanced Materials and Life Science Division, Istituto Nazionale Ricerca Metrologica, Strada delle Cacce 91, 10135 Torino, Italy; 2 Physikalisch-Technische Bundesanstalt (PTB), Abbestr. 2-12, 10587 Berlin, Germany; 3 Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi, 24, Torino, Italy; 4 AG Nanostrukturierung, Nanoanalyse und Photonische Materialien, University of Paderborn, Warburger Str. 100, 33098 Paderborn, Germany;

Resume : Sequential infiltration synthesis (SIS) [1] consists of the cyclic exposure of a polymer to gaseous precursors used in atomic layer deposition (ALD), resulting in the growth of inorganic compounds. SIS is a promising technique for many applications, including the realization of complex inorganic nanostructures in block copolymers (BCPs) templates for microelectronics. In PS-b-PMMA BCPs systems, Al2O3 is grown by the reactions of trimethyl-aluminium (TMA) and H2O and infiltrates selectively in PMMA nanodomains due to their chemical affinity to TMA. The role of PS as a diffusion channel has been proposed to describe the mechanism of infiltration [2], however, the complete understanding of the process is still sought. In this study, we combine grazing-incidence X-ray fluorescence (GIXRF), transmission electron microscopy (TEM) and energy dispersive X-ray microanalysis (EDX) to provide insights into such a mechanism. Reference-free GIXRF analysis [3] was performed on a layer of PMMA resist for electron beam lithography (EBL), PS-r-PMMA and PS-b-PMMA layers infiltrated with Al2O3 in 1 to 10 cycles of ALD to obtain the absolute quantification of the aluminum content. GIXRF depth-dependent information on the distribution of target elements can be complemented with the imaging of the cross-sectional view of infiltrated polymer and chemical analysis provided by EDX. [1] Y. C. Tseng, et al., J. Mater. Chem, 21, 2011, 11722. [2] M. Biswas, et al., J. Phys. Chem. C, 119, 2015, 14585. [3] P. Hönicke, et al., Phys. Status Solidi A, 212 (3), 2015, 523.

Authors : Andreas Hertwig, Elena Ermilova, Uwe Beck
Affiliations : Federal Institute for Materials Research and Testing (BAM), Div. 6.7, Unter den Eichen 44 - 46, 12203 Berlin,; Federal Institute for Materials Research and Testing (BAM), Div. 6.7, Unter den Eichen 44 - 46, 12203 Berlin; Federal Institute for Materials Research and Testing (BAM), Div. 6.7, Unter den Eichen 44 - 46, 12203 Berlin

Resume : Ellipsometry is a highly sensitive optical surface analysis tool. Due to its unique properties as a method, it is fast, easy to implement and highly scalable while remaining one of the most surface sensitive methods. In this presentation, we will report on the current state of standardised measurements with ellipsometry and on best practices for using it to determine surface properties. This field has proven to be very difficult in the past as ellipsometry usually relies on model-based data analysis. Extensive work is currently done to describe ellipsometry as a method with respect to quantified accuracy as well as traceability. This work is in parallel done for specific classes of samples and with a generalised sample-independent approach, as demonstrated in DIN 50989-1 and ISO CD 23131. We present the current description of the method with respect to standardisation and accuracy and show its usefulness with a collection of examples involving complex analysis work. We use these examples from internal and laboratory comparison projects to show how ellipsometry can be performed in a traceable way and to explore how measurement uncertainties can be calculated. Finally, we will introduce a best practice guide developed by the EMPIR HyMET project on how to measure complex surface parameters by means of a multi-method approach.

Authors : Maxim Shkunov(1), Sebastian Wood(2), Ruth Rawcliffe(1), Filipe Richheimer(2), Tomas Peach(1), Fernando Castro(2)
Affiliations : (1) Advanced Technology Institute, Faculty of Engineering & Physical Sciences, University of Surrey, Guildford, UK; (2) National Physical Laboratory, Teddington, Middlesex, UK

Resume : Nano-characterisation techniques, including confocal microscopy, atomic force microscopy (AFM) and tip enhanced Raman scattering (TERS), rely on the ability of each instrument to resolve nano-scale features without distortions and artefacts, however, reference samples allowing to perform fully quantitative characterisation of their responses are not available. Calibration of lateral and depth resolution of advanced scanning-probe microscopy methods is currently very challenging and calls for the development of nanoscale standards with features in 10-200 nm range with various morphological and optoelectronic characteristics. We demonstrate the development of single-nanowire-based reference samples, where easily identifiable device positions each contain a semiconducting nanowire with a particular set of properties. Key parameters that are considered include: diameter and length, Raman response, photoluminescence and conductivity. The devices are self-assembled from a wide range of solution-processed semiconducting nanowires, including Si, Ge, InAs, InP, GaN, Ge/Si. Individual nanowires are positioned in pre-defined locations using electric-field assisted process, dielectrophoresis (DEP), by applying controllable DEP signal voltage and frequency. Nanowires are characterised, and various response metrics are analysed using conducting-AFM, confocal Raman, TERS and other techniques to establish which nanowire materials provide highly distinguishable responses, necessary for reference standards. Challenges in identifying most suitable nanowire materials, including their spectroscopic characteristics (e.g. Raman) and morphological features (e.g. diameters) are discussed and several reference samples for the characterisation of lateral and vertical resolution of nanoscale scanning probe techniques are suggested.

Authors : Yves Kayser1, Philipp Hönicke1, André Wählisch1, Markys Cain2, Paul Thompson3,4, and Burkhard Beckhoff1
Affiliations : 1 Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany 2 Electrosciences Ltd., Osborn Road, Farnham, Surrey, GU9 9QT, United Kingdom 3 European Synchrotron Radiation Facility, 71 Avenue des Martyrs, 38000 Grenoble, France 4 Department of Physics, University of Liverpool, Liverpool, L69 3BX, United Kingdom

Resume : Within the EMPIR project ADVENT, in which the metrology for advanced energy-saving technology in next-generation electronics applications is further developed, the Physikalisch Technische Bundesanstalt (PTB), Germany´s national metrology institute, contributes to the characterisation of novel ferro- or piezoelectric materials by using traceable X-ray methodologies for the in-situ characterisation of advanced materials. Therefore extended X-ray absorption fine structure (EXAFS), which allows determining the atomic coordination within the investigated material under in-situ conditions, is applied towards operando measurements of the response of PZT-films to alternating electric fields applied at a frequency in the megahertz range. We will present the current progress towards time-resolved traceable atomic coordination measurements of piezoelectric materials proposed for the next generation of ultra-low power energy-efficient devices. The provision of analytical information on real materials within operational environments allows, in conjunction with complementary analytical techniques, linking the intrinsic physical phenomenon to the materials? macroscopic functional and structural properties.

Authors : Jan Martinek, Vaclav Hortvik, Miroslav Valtr, Petr Klapetek
Affiliations : Czech Metrology Institute, Okruzni 31, 638 00 Brno, Czech Republic

Resume : Mapping temperature distribution on an active microelectronic circuit is a way how to evaluate the circuit performance, locate the hot spots and better understand processes leading to potential device failure. Different methods are being used for these purposes, either contact or non-contact, having different spatial and temperature resolution and being based on different traceability chains. In this contribution we will concentrate on two of them, Scanning Thermal Microscopy and infrared microscopy. We will present key systematic errors in both types of measurements, best practices for making the measurement traceable and whole toolchain needed for interpreting the measured results. We will also discuss benefits and drawback compared to other high resolution thermal techniques, e.g. thermoreflectance measurements. The uncertainty sources will be estimated on basis of both measurments and numerical calculations. Quantitative results with examples of the full uncertainty budget will be demonstrated for measurements on commercially available integrated circuits.

Authors : T. Le Quang, D. Vasyukov, J. Hoffmann, A. Buchter, M. Zeier
Affiliations : Federal Institute of Metrology (METAS)

Resume : Scanning microwave microscopy (SMM) is a still rather new member of the family of scanning probe techniques. It has attracted attention due to its ability to characterize various electrical properties of samples. The basic working principle is to send a microwave signal to the scanning tip, where it is reflected depending on the sample underneath. The material parameters at the tip-sample contact determine the measured reflection coefficient, S11, in amplitude and phase Here, we present our works to produce and characterize capacitive devices, which can be used as impedance standards to calibrate the SMM. The sample fabrication was done in a clean room to produce different gold micron-size structures supported by a free SiN membrane. After the fabrication, high resolution scanning electron microscope images were taken and analyzed. Then, analyzed images were imported into Comsol Multiphysics in order to estimate the capacitance of these devices. SMM measurements were conducted using our tuning-fork based SMM under ambient conditions with microwave frequencies between 1 and 50 GHz. Measured S11 signals show a clear contrast between regions with different impedance/capacitance. Last but yet importantly, we were able to demonstrate that the calibration method proposed by Hoffmann and others [1] can be applied to the SMM measurements our impedance standards. References: 1. J. Hoffmann, et al. (2018), A Calibration Algorithm for Nearfield Scanning Microwave Microscopes, IEEE-NANO, 2012.

Authors : B. Kaestner (1), E. Pfitzner (2), G. Ulrich (1), X. Hu (1), H. W. Schumacher (1), A. Hoehl (1), D. Venkatehvaran (3), J. Heberle (2), J. Wunderlich (4)
Affiliations : (1) Physikalisch-Technische Bundesanstalt, Braunschweig and Berlin, Germany; (2) Freie Universität Berlin, Berlin, Germany; (3) Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom; (4) Universität Regensburg, Regensburg, Germany

Resume : Infrared photocurrent mapping has rapidly developed in recent years. Here we present a near-field induced contrast mechanism arising when a conducting surface, exhibiting a magnetic moment, is exposed to a nanoscale heat source. The magneto-caloritronic response of the sample to near-field excitation of a localized thermal gradient leads to a contrast determined by the local state of magnetization. The impact of this finding is threefold: 1) It allows non-invasive imaging of magnetic nanostructures as it does not rely on the magnetic dipole interaction, as in conventional high-resolution scanning magnetic force microscopy where the sample magnetization can be affected by the stray-field of the scanning magnetic tip. 2) It represents an approach towards thermal and electric field nanometrology. 3) The contrast mechanism itself may be turned into a novel nano-spectroscopic tool for thin organic layers, forming a hybrid material with a well characterized magnetic substrate. Illustrative examples for the three directions above will be presented.

Authors : Bernd Bayerlein*(1), Yves Kayser (2), Bernd Kästner (2), Jose Moran (3) & Axel Kranzmann (1) * lead presenter
Affiliations : (1) Bundesanstalt für Materialforschung und -prüfung, Unter den Eichen 87, 12206 Berlin, Germany; (2) Physikalisch-Technische Bundesanstalt, Abbestr. 2-12, 10587 Berlin, Germany; (3) Laboratoire national de métrologie et d'essais, 29 av. Roger Hennequin 78197 Trappes Cedex, France;

Resume : Over the last decades the Focused Ion Beam (FIB) microscope became an indispensable tool for fundamental materials and applied research. Dual-beam systems comprise a FIB column where a focused beam of typically gallium ions originates from a liquid-metal ion source and a scanning electron microscope (SEM) column providing a focused beam of electrons. This arrangement enables precise structuring and high-resolution imaging at the same time. Equipped additionally with gas injection systems, hydrocarbon precursor gases can be inserted in the chamber allowing a local deposition of conducting (Pt, W, C) or insulating materials. One of the main advantages employing FIB instrumentation is that internal micro- and nanostructural sample features become accessible for site- and orientation-specific target preparation. However, the scope of applications of this technique goes beyond preparation of thin-foil samples for transmission electron microscopy. Here, the potential of FIB instrumentation for the fabrication of nanostructured devices from layered semiconductor material systems (PZT, AlGaN/GaN and AlN/GaN) for different analytical techniques such as Infrared Scanning Near-field Optical Microscopy, Scanning Microwave Microscopy and X-ray Spectrometry will be demonstrated.


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Symposium organizers
Burkhard BECKHOFF (Main)Physikalisch Technische Bundesanstalt

Abbestrasse 2-12, Berlin, Germany
Fernando Araujo de CASTRONational Physical Laboratory

Hampton Road, Teddington TW11 0LW, U.K.

Strada delle Cacce 91, 10135 Torino, Italy
Marie-Christine LEPYLNE / Laboratoire National Henri Becquerel

CEA Saclay, F- 91191 Gif-sur-Yvette, France