preview all symposia

2022 Spring Meeting

Nanoelectronic materials and devices


Materials for nanoelectronics and nanophotonics

This symposium will cover:

  1. Materials Synthesis: From 0D to 3D functional nanomaterials including hybrids.
  2. Properties: Electronics, optical, photonics, luminescent (experimental, analytical, modelling).
  3. Applications: Electronics, sensing, photonics, plasmonics, luminescent, optoelectronics, energy.


Nanostructures, particularly from inorganic materials, ceramics, carbon, etc. family, are very important candidates because of their extremely high surface-to-volume and morphology-dependent extraordinary properties suitable for many advanced technologies. The ongoing deployments in the direction of confined nanostructures (0D, 1D, 2D) and their porous interconnected 3D networked materials have further become very relevant towards various applications. The porous 3D network material built out of nanoscale building blocks, offers very lot of utilization simplicities and simultaneous easy accessibility of nanoscale features make them very excellent candidates for applications, especially towards electronics and optics. Due to their compact synthesis forms, they can be easily handled or integrated in the desired manner in nanoelectronics devices or sensors. The confined nanostructures from noble metals (Au, Ag, Cu, etc.) have found immense applications in electronics, optoelectronics, sensing, photonics, and waveguides, etc. Nanostructures from metal oxides have been very interesting (fundamental as well applied) materials due to interesting bandgap values (intermediate between metals and insulators), suitable for various advanced electronic, optical, optoelectronic and sensing technologies. When these metal oxides and metals are combined together in nanohybrids, they become further very relevant in terms of understanding the properties and accordingly electronics and optoelectronics applications. The carbon nanostructure family, i.e., fullerenes, carbon nanotubes, graphene, graphene oxide, etc., have shown very strong potentials in terms of fundamental properties as well as advanced electronics and optical applications and hence have been the subject of huge research attention in the last couple of decades. Recent developments in the direction of 3D carbon based networked materials have opened many new avenues in the direction of electronics and optics fields. The research on metal oxide nanostructures based three dimensional interconnected ceramics networks is currently in the main focus because they can be utilized as unique backbone for developing hybrid nanomaterials. The nanostructures from inorganic, metal oxide and carbon, etc. materials can be easily integrated in form of hybrid 3D networks which involves new structure dependent electronic and optical features for advanced nanoelectronics and nanophotonics related applications.

Appropriate growth strategies of different confined nanostructures using simple methods, understanding their different properties, and applications of these pure and hybrid materials in the direction of nanoelectronics and nanophotonics are key fundamental issues to which this proposed symposium in E-MRS Spring 2020 is going to briefly address. Researchers with interdisciplinary expertizes could easily help each other to realize the materials growth and corresponding structure-property relationships. In this proposal it is aimed to bring: (i) synthesis groups for developing different nanostructures, (ii) theoretical/modelling scientists, (iii) experts from electronics and photonics fields who can accordingly utilize these materials in various applications, together to develop a discussion platform with the theme ‘materials for nanoelectronics and nanophotonics’ at EMRS Spring meeting in 2020 in Strasbourg, France. Over the last few years, perovskites, rare earth based nanocrystals have gained significant attentions from electronics and photonics aspects. They have been intensively explored for light emission and photovoltaic applications. Recent developments towards synthesis, theoretical and applications of these advanced nanomaterials will also be covered in this symposium during E-MRS Spring 2022 in Strasbourg.

Topics to be covered by the symposium:

  • Hybrid materials: Synthesis, Characterizations, Structure-property relations, Analytical and simulation studies, Applications: Nanoelectronics, Sensing, Nanophotonics, Optics, Luminescent, etc.
  • Nanoelectronics: Electronics, Sensing, Energy, Photovoltaics, Piezoelectric, Piezotronics, etc.
  • Nanophotonics: Optics, Photonics, Plasmonics, THz optics, Luminescent, Waveguides, Whispering gallery modes, Light emitting diodes, Lasers, Imaging, Advanced lightening technologies, etc.
  • Nano optoelectronics: UV and photodetection, Photovoltaics, Solar cells, etc.

List of invited speakers:

  • Ioannis Papakonstantinou, University College London, UK
  • Gilles Ledoux, CNRS, France
  • Adel Mesbah, CNRS, France
  • Morten Willatzen, Chinese Academy of Sciences, China
  • Prashanth W. Menezes, Helmholtz Centrum Berlin, Germany
  • Satheesh Krishnamurthy, Open University, UK
  • Manish Tiwari, University College London, UK
  • Alireza Dolatshahi-Pirouz, DTU, Denmark
  • Amit Bhatnagar, LUT, Finland
  • Raghuraj Singh, JSI, Slovenia
  • Adarsh Pandey, Sunway University, Malaysia
  • Cenk Aktas, Kiel University, Germany
  • Sanjay Mathur, University of Cologne, Germany
  • Alberto Vomiero, Luleå University of Technology, Sweden
  • Sreetosh Goswami, Center for Nano Science and Engineering, Bangalore, India
  • Fabian Schütt, Kiel University, Germany
  • Samit K. Ray, IIT Kharagpur, India
  • Ivo Kuřitka, Thomas Bata University, Czech Republic
  • Pramod Kumar, QuantLase Lab, UAE
  • Karthik Shankar, University of Alberta, Canada



230.63 KbDownload
Start atSubject View AllNum.
08:00 Welcome and Introduction to the Symposium    
Plasmonic Nanomaterials : Jost Adam, Yogendra Kumar Mishra, Ayan Chaudhuri
Authors : Funes-Hernando Daniel [1], Peláez-Fernández Mario [2], Winterauer Dominik [3], Mevellec Jean-Yves[1], Arenal Raúl [2,4], Batten Tim[3], Humbert Bernard [1], Bayle Maxime [1], Duvail Jean-Luc [1]
Affiliations : [1] Institut des Matériaux Jean Rouxel, UMR 6502 CNRS and Nantes University, Nantes, France [2] Laboratorio de Microscopias Avanzadas, Instituto de Nanociencia de Aragon, Universidad de Zaragoza, Zaragoza, Spain [3] Renishaw plc, New Mills, Wotton-under-Edge, United Kingdom [4] ARAID Foundation, 50018 Zaragoza, Spain

Resume : At the frontier of nanophotonics and nanoelectronics, plasmonic nanowires are promising building blocks for plasmonic-based devices, such as nano-sources and nano-sensors. The 1D morphology allows the guiding of propagative surface plasmon polaritons (SPP) at a sub-wavelength scale. The nanowire tips are of particular interest for allowing in- and out-coupling, because they are the place where the SPP can be initiated and where non-radiative SPP can be scattered to promote light emission. Different kinds of gold-based nanowires have been recently designed in our group for different purposes. In a first study, coaxial hybrid nanowires were fabricated and optimized for SPP-mediated remote Raman effect. The remote Raman spectroscopy consists in the separation by many micrometres of the excitation laser spot on one tip of the nanowire, and the Raman detection at the opposite tip. A gold core was exploited to guide SPP propagation at the metal-air interface along micrometers. The detection of the Raman signal of a very thin and short shell of poly(3,4-ethylene-dioxythiophene) (PEDOT) located at the opposite nanowire tip validated the design and the efficiency of this remote sensor. However, the intrinsic low intensity of the Raman signal is a weakness for extremely sensitive nano-sensors. In order to tackle this point, we propose to enhance the overall signal by improving the in-coupling of the focused laser (1 µm diameter, typically) with the nanowire and the out-coupling of light from the plasmon-mediated signal at the remote location. Dry laser heating treatment was used to enlarge the gold nanowire tips to obtain dumbbell-like nanowires. By a micro-Rayleigh scattering study, the excrescence located at one or at the two tips of the nanowires provides an enhanced in- and out-coupling. Their plasmonic properties have been investigated by an EELS-STEM study.

Authors : Chiao-Jung Su, Yu-Ling Chang, Yi-Chia Hsieh, Li-Chia Lu and Dehui Wan*
Affiliations : Institute of Biomedical Engineering and Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu, Taiwan; Department of Materials science and Engineering, National Tsing Hua University, Hsinchu, Taiwan

Resume : The inherent quasi-3D structure and the concentration effect of the hydrophobic paper led to a significant enhancement in the Raman scattering.[1] On the other hand, size-tunable aluminum nanoparticles (AlNPs) have been suggested as a remarkably low-cost alternative plasmonic material due to its adjustable localized surface plasmon resonance band from UV-visible to near-infrared (NIR) regions.[2] Herein, we combine the merits of the AlNPs and hydrophobic paper to introduce a sensitive but cost-effective Al paper-based SERS sensing platform. Initially, AlNPs in different diameters were synthesized. Then, the 3D finite-difference time-domain (FDTD) optical simulation was applied to investigate the optimal size and density of the AlNPs, which contribute to the strongest electric field intensity and the desired electric field distribution. Next, a 785 nm portable Raman spectrometer was chosen to test out the possibility of the Al paper-based SERS sensing platform as an on-site detection platform. Namely, the Al paper-based SERS sensing platform was utilized to identify different colorants, which are Erythrosine (ER), Rhodamine B (RB), and Allura red (AR). Among the three additives, Rhodamine B (RB) has been regarded as an industrial colorant, therefore, its use in food industries is strongly restricted worldwide. In addition to pure colorants, a sample that combed the three additives, a candy blended with RB were also prepared to simulate the complex environment in a real scenario. Apparently, the Al paper-based SERS sensing platform has proven its effectiveness as an on-site detection tool by rapidly distinguishing different kinds of colorants in all samples. Moreover, the Al paper-based SERS sensing platform was also used to sense two environmental pollutants, Benzo[a]pyrene and Phenanthrene. In a nutshell, through decorating the AlNPs on hydrophobic paper, we established a novel on-site SERS sensing platform with excellent sensitivity and notably low cost, which is hard to achieve in other conventional materials. Reference: 1. Lee, M., et al., Subnanomolar Sensitivity of Filter Paper-Based SERS Sensor for Pesticide Detection by Hydrophobicity Change of Paper Surface. ACS Sensors, 2018. 3(1): p. 151-159. 2. Renard, D., et al., Polydopamine-Stabilized Aluminum Nanocrystals: Aqueous Stability and Benzo[a]pyrene Detection. ACS Nano, 2019. 13(3): p. 3117-3124.

Authors : Regina M. Chiechio 1,2,8, Celia Marets 1, Pascale Even-Hernandez 1, Christelle Meriadec 3, Franck Artzner 3, , Rémi Leguevél 4, Helene Solhi 4, Marie Madeleine Gueguen4, Stephanie Dutertre 5, Xavier 5, Jean-Pierre Bazureau 1, Olivier Mignen 6,7, Paolo Musumeci 2, Maria Jose Lo Faro 2,8, Valerie Marchi 1*
Affiliations : 1) Université Rennes 1, CNRS UMR 6226, Institut des Sciences Chimiques de Rennes, 35042 Rennes Cedex, France; 2) Dipartimento di Fisica e Astronomia “Ettore Majorana”, Università degli Studi di Catania, Via S. Sofia 64, 95123 Catania, Italy. 3) CNRS, Institut de Physique de Rennes, UMR 6251, Université de Rennes 1, F-35000, Rennes, France 4) ImPACcell platform, Biosit, Université de Rennes 1, F-35043 Rennes, France; 5) Microscopy Rennes Imaging Centre, SFR Biosit, UMS CNRS 3480—US INSERM 018, Université de Rennes, 35000 Rennes, France 6) University of Brest, INSERM, Canalopathies et Signalisation Calcique, Brest, France; 7) University of Brest, INSERM, Lymphocytes B et auto-immunite´, Brest, France. 8) Istituto per la Microelettronica e Microsistemi, Consiglio Nazionale delle Ricerche (CNR-IMM) UoS Catania, Via S. Sofia 64, 95123 Catania, Italy.

Resume : The high electron density and ultra-small dimensions generate unique photoelectrochemical and luminescence properties in gold nanoclusters (Au NCs) that make them particularly suitable for biological applications such as diagnosis, bio-imaging and theranostics. These applications require a study of the interaction between nanoparticles and cells, in particular with the cell membrane, in addition to the control of their delivery in the site of interest. For these reasons, an accurate engineering of Au NCs surface chemistry is essential since it allows to control their interaction with lipid membranes. In this work the ability of AuNCs as markers of lipid structures is demonstrated, and more particularly the electrostatic interactions by Zetametry and the localization on the lipid membrane by SAXS is investigated. A simple method of encapsulating AuNCs within liposomes is also presented to limit non-specific interactions and for drug delivery. Ultimately, the application of these nanostructures as luminescent probes for labeling the membrane and nucleus of pancreatic tumor cells is showed. These nanostructures can therefore represent a multivalent, luminescent and non-toxic platform capable of specifically recognizing tumor cells or other biological objects for bioimaging, drug delivery and radiosensitizing applications.

Authors : Kenan Elibol and Peter A. van Aken
Affiliations : Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany

Resume : The location and optical field profiles of plasmonic hotspots are critical for applications in potochemistry and optoelectronics. These parameters can be tuned by controlling the size and position of nanoparticles. Here we fabricate aluminum nanocavity arrays including bowtie and tetramer structures on a CVD-grown monolayer graphene by electron beam lithography. Subsequently we confine platinum (Pt) nanoclusters within the plasmonic hotspots of these nanocavities by thermal annealing. The localized surface plasmon resonances (LSPRs) of nanocavities on the graphene membrane are revealed via electron energy-loss spectroscopy as well as energy-filtered transmission electron microscopy in a monochromated scanning transmission electron microscope (STEM) and are confirmed by electromagnetic simulations. Both nanocavity structures support the excitation of non-radiative dipolar dark and radiative dipolar bright LSPR modes that can be tuned by controlling the gap size of the structures. We further demonstrate the realization of weak and strong coupling between the dipole modes of trapped Pt nanoclusters and the dipolar dark modes of bowties. Interestingly, the dipole mode of Pt nanoclusters also couples to the bonding-type breathing mode of bowties. Our findings suggest that the hybrid nanocavity-graphene system is promising for plasmon-mediated catalysis, surface-enhanced fluorescence, and quantum technologies.

Authors : Alice Sciortino, Sourov Chandra, Faisal Ahmed, Diao Li, Arijit Jana, Ville Liljeström, Hua Jiang, Leena-Sisko Johansson, Xi Chen, Nonappa, Thalappil Pradeep, Marco Cannas, Zhipei Sun, Olli Ikkala, Fabrizio Messina
Affiliations : University of Palermo; Aalto University; Aalto University; Aalto University; Indian Institute of Technology; Aalto University; Aalto University; Aalto University; Aalto University; Aalto University; Indian Institute of Technology; University of Palermo; Aalto University; Aalto University; University of Palermo;

Resume : Gold nanoclusters (GNCs), as atomically precise metal nanoclusters covered by organic ligands, are an emerging class of luminescent nanomaterials displaying excellent optical properties, photostability and high biocompatibility, interesting characteristics for fundamental and technological reasons. Very few studies so far have focused on ultra-small nanoclusters, with Au cores smaller than 10 atoms, despite they should display a range of peculiar and appealing properties Studies on their electronic properties are moved by the interest on understanding the mechanisms behind the optical properties, indeed metal nanoclusters (NCs) can fill the gap between small molecules and bigger nanoparticles. Despite NCs sometimes are assimilated to molecules, their photophysics can be more complex and not trivially describable in terms of a simple “molecular-like” behavior. A lively debate exists on the attribution and localization of electronic transitions: while the optical properties are often attributed to localized transition on the gold core, other works provided evidence of the role played by the organic ligand in a ligand to metal charge transfer transitions (LMCT). Here, we prepared ultra-small gold nanoclusters having strong emission in yellow-green spectrum regions. 6-(Dibutylamino)-1,3,5-triazine-2,4-dithiol is used as a ligand, which significantly stabilize the Au-core containing only 6 atoms of Au in an octahedral structure as demonstrated by experimental and DFT analysis. We perform a complete optical characterization of the small NCs from steady state to the femtosecond regime discovering that the photocycle is controlled by LMCT transitions proceeding directly from the ligands to the core without any intermediates. The energy cascade from the initially excited state involves an ultra-efficient (150 fs) intersystem crossing which is followed by a fully coherent, extremely fast pathway, involving the generation of core vibrational wavepackets that are damped through successive relaxation. The results provide fundamental insight on the photophysical response of ultrasmall nanoclusters and highlight their potential interest for a range of prospective technological applications in photonics and optoelectronics.

Authors : Bing Ni
Affiliations : University of Konstanz

Resume : Inorganic chiral nanomaterials are now attracting more and more attention due to their versatile properties [1]. The interaction of light could be much stronger in inorganics, which could lead to significantly higher dissymmetry factors (the absorption difference between left- and right polarized light compared to the average of the absorptions, or referred to g factors). Such high g factors, together with nanotechnology, are promising in new technological solutions in many fields. However, the development of inorganic chirality was largely limited by the fabrication of chiral inorganic materials with high quality. Synthesis is the core of material science, since it provides substances for research. A good synthesis methodology is essential to all the following researches. Here we developed a symmetry-based kinematic theory (SBKT) to guide the design of chiral Au nanoparticles (NPs) [2]. This mechanism is based on the classical BCF theory and kinematic theory. By applying symmetry to the theories and further considering the properties of kinematic waves at nanoscale, the shape evolution trajectory could be easily illustrated. The hierarchy of the concepts in this theory is (level 1) shape evolution; (level 2) preferential growth directions (PGDs), kinematic wave; (level 3) surface nucleation, layer advancement; (level 4) atom deposition, surface atom diffusion. Atom deposition and surface diffusion are the basic growth processes. They are highly influenced by the growth environments, including precursor concentrations, ligands, nuclei or seed structures, temperature, etc. The formation of a surface nucleus indicates that the surface adatoms at this area (deposited either by direct deposition or atom diffusion) are stable. The layer advancement could be partly seen as the ensemble of surface diffusion, while the kinematic wave is the collective behavior of layer advancements. The shape evolution is at the top level, and to illustrate it, it is just needed to focus on the PGDs and the properties of the kinematic wave. The growth trajectory would be defined by the PGDs, and modified by the properties of kinematic waves under the corresponding growth conditions. The SBKT shows great advantages in explaining the symmetry breaking process during the growth compared with other growth theories. Furthermore, the SBKT has been well-confirmed in the seed mediated growth of Au NPs. With a clear image of how the shape evolves at nanoscale, we used cysteine as the chiral inducer to influence the layer advancement process in order to obtain chiral Au NPs. Accordingly, various chiral Au NPs with different g factors were successfully prepared [3]. Among them, the twisted Au NPs showed a g factor of -0.10, which was much stronger than most of the reported results. [1] B. Ni, H. Cölfen, SmartMat, 2021, 2, 17-32 [2] B. Ni, H. Cölfen, manuscript submitted to Angew. Chem. [3] B. Ni, H. Cölfen, manuscript in preparation

10:15 Discussion    
10:30 Break    
SERS Sensing : Yogendra Kumar Mishra, Duvail Jean-Luc, Dawid Janas
Authors : Spitaleri, L.*(1) & Gulino, A. (1)
Affiliations : (1) Department of Chemical Sciences, University of Catania, and INSTM UdR of Catania, V.le A. Doria 6, 95125 Catania, Italy

Resume : Gold nanoparticles (Au NPs) have attracted great attention due to their tuneable and distinctive chemical, optical, magnetic, and electronic properties, employed in a wide variety of areas, such as electronics, photonics, catalysis, and biomedicine.[1] Depending on their size, Au nanoparticles can alternately show surface plasmons or luminescence. In fact, the increase in the size of the Au NPs, and the appearance of the surface plasmons may result in the disappearance of luminescence. In this context, the design of hybrid plasmonic and luminescent nanomaterials using a bottom-up approach is suitable for the manufacture of functional nanocomposites that display structural control and novel properties, e.g. optical, electronic or catalytic properties, in the perspective of their applications in different fields of nanotechnology.[2] In addition, the combination of different optical properties belonging to the different molecular components represents an advanced method to manufacture hybrid assemblies, useful for improved optical applications. Porphyrins and metalloporphyrins exhibit luminescence properties, sensing capabilities, non-linear optical behaviours, biological roles, magnetic properties, and more.[3] Furthermore, porphyrin molecules, covalently grafted to electroactive metal oxide substrates, can also be used for molecular-based information storage materials, whereby information can be stored in the discrete redox states of the molecules. In this context, the aim of this work was the synthesis of a new composite assembly consisting of porphyrin monolayer covalently anchored to inorganic functionalized substrates, conjugated with an additional Au NP monolayer, thanks to the strong binding affinity of Au NPs to pyridyl moieties present in the structure of porphyrin molecules. This nanocomposite 3D architecture exhibits both a strong surface plasmon, due to the gold nanoparticles, and an intense luminescence signal from the porphyrin monolayer molecules. Therefore, we fabricated an optically active archetypal setup that shows distinct optical outputs depending on the excitation wavelength (input), which is of interest for advanced signaling and communication systems. Moreover, the present plasmonic material may be also of interest for photocurrent generation in solar energy conversion systems. Finally, the appropriate choice of this porphyrin as a molecular cross-linker resulted in the structural control of the gold surface structures that are parallel to each other, and evidence a long-range linear order. [1] R. Jin, C. Zeng, M. Zhou, Y. Chen, Chem. Rev. 2016, 116, 10346. [2] J. Yan, B. K. Teo, N. Zheng, Acc. Chem. Res. 2018, 51, 3084. [3] M. O. Senge, N. N. Sergeeva, K. J. Hale, Chem. Soc. Rev. 2021, 50, 4730.

Authors : Jaione Etxebarria-Elezgarai* (1), Luca Bergamini (2,3), Eneko Lopez (1), Jost Adam (4), Nerea Zabala (2,3), Javier Aizpurua (3), Andreas Seifert* (1,5)
Affiliations : (1) CIC nanoGUNE BRTA, Tolosa Hiribidea 76, 20018 San Sebastian, Spain (2) Department of Electricity and Electronics, FCT-ZTF, UPV-EHU, 48080 Bilbao, Spain (3) Materials Physics Center, CSIC-UPV/EHU and DPIC, 20018 San Sebastian, Spain (4) University of Southern Denmark, 6400 Sønderborg, Denmark (5) IKERBASQUE, Basque Foundation for Science, Euskadi Plaza 5, 48009 Bilbao, Spain

Resume : We present a highly sensitive plasmonic sensing approach in Kretschmann configuration that additionally includes dielectric features from Fresnel reflections and combines multiple sensitive features of the reflectance curve by multivariate analysis. The sensor consists of periodic gold nanostructures, which are integrated into a microfluidic chamber composed of several dielectric layers. We operate the sensor at single wavelength with angular scan using a p-polarized HeNe laser. The excitation of the whole device in Kretschmann configuration leads to complex multiple plasmonic resonances, generally with localized surface plasmon resonances, plasmonic surface lattice resonances, and resonances related with the evanescent field beyond total internal reflection. Additionally, characteristic features generated due to Fresnel reflections from the stack of different dielectric interfaces of the whole sensing device, including a microfluidic chamber, contribute in a sensitive way to the sensing performance. These dielectric features can be exploited additionally as sensitive sensing characteristics with respect to refractive index changes of the analyte under test. The increased number of features obtained from the plasmonic response together with the multiple reflections at the dielectric interfaces reveal strongly enhanced sensing capabilities when we combine them as input for multivariate analysis. By mathematically including a variety of characteristic features of the reflectance curve, the analytical sensitivity and the sensor resolution are improved by 200% and 23%, respectively; moreover, the prediction error is reduced by around 38% compared to a standard plasmonic sensor based on a continuous gold layer.

Authors : Agata Fularz, Sawsan Almohammed, and James H. Rice
Affiliations : Agata Fularz - School of Physics, University College Dublin, Dublin 4, Ireland Sawsan Almohammed - School of Physics, University College Dublin, Dublin 4, Ireland; Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, Ireland James H. Rice - School of Physics, University College Dublin, Dublin 4, Ireland

Resume : The detection of analytes using spectroscopy methods, such as surface enhanced Raman spectroscopy (SERS) as well as fluorescence spectroscopy, is crucial in the fields of medical diagnostics, forensics, security, and environmental monitoring. In recent years, a lot of focus has been directed towards organic, green, and sustainable polymer material-based sensing platforms due to their lower cost, controllable synthesis and fabrication, structural versatility, as well as biocompatibility, and biodegradability. Here we report that cellulose nanofiber-based substrates can be used as metal-free SERS and fluorescence spectroscopy platforms for the detection of a wide variety of molecules with the focus on porphyrin-type molecules. We report 2-orders of magnitude peak intensity enhancement observed resulting in a detection limit of 10 micromolar for metal-free SERS enhancement on cellulose. Additionally, various important biomolecules including a model bioassay can be detected on cellulose-based substrates via fluorescence spectroscopy at concentrations as low as 100 nanomolar. We attribute the observed enhancement to a charge transfer process, as well as nanofiber-driven clustering of the analyte molecules. The cellulose-based platforms are characterized by performance comparable to that of traditionally used metal-based templates, while being cost-effective, biocompatible, robust, and recyclable.

Authors : Sadok Kouz1,2*, Awatef Ouhibi1, Amal Raouafi3, Nathalie Lorrain2, Noureddine Raouafi3, Adel Moadhen1 and Mohammed Guendouz2
Affiliations : 1Université de Tunis El Manar, Faculté des Sciences de Tunis, Laboratoire de Nanomatériaux Nanotechnologie et Energie (LR19ES23), 2092, Tunis El Manar, Tunisie 2UMR FOTON, CNRS, Université de Rennes 1, Enssat, BP 80518, 6 rue Kerampont, F22305, Lannion, France 3Université de Tunis El Manar, Faculté des Sciences de Tunis, Laboratoire de Chimie Analytique et Electrochimie (LR99ES15), sensor and biosensors group, 2092, Tunis El Manar, Tunisie

Resume : The global pandemic in 2020 caused by the new strain of coronavirus SARSCoV-2, has highlighted the need for faster and more efficient ways for the detection of viral infections. In our work, a new surface-enhanced Raman scattering (SERS)-based aptasensor platform capable of detecting the SARS-CoV-2 with a high sensitivity is developed. The aptamer Deoxyribonucleic acid (DNA) is used as a receptor, and a silicon nanowires substrate (SiNWs) decorated by Ag nanoparticles (AgNPs) is used as a SERS sensitive sensor of SARS-CoV-2 N protein. The SiNWs fabrication and AgNPs decoration are achieved by a relatively simple wet chemical processing method [1]. A quantitative analysis of the SARS-CoV-2 lysate is performed by monitoring the change in the SERS peaks intensity caused by the new binding between the aptamer DNA released from the AgNPs/SiNWs surface and the N protein in the SARS-CoV-2 virion. This technique enables detecting SARS-CoV-2 with a limit of detection (LoD) of less than 5 ng/mL within 30 min. This methodology is a very cheap, robust, rapid and requires very small sample volumes, which can help in the diagnosis domain of infections at very early stages. The results of this study demonstrate the possibility of a clinical application that can dramatically improve the detection limit and accuracy of the currently commercialized SARS-CoV-2 immunodiagnostic kit. [1]: Awatef Ouhibi, Amal Raouafi, Nathalie Lorrain, Mohammed Guendouz, Noureddine Raouafi, Adel Moadhen, Functionalized SERS substrate based on silicon nanowires for rapid detection of prostate specific antigen, Sensors and Actuators B: Chemical, Volume 330, 2021.

Authors : András Pálinkás, György Molnár, Gábor Piszter, András Deák, Zoltán Osváth
Affiliations : Centre for Energy Research, Institute of Technical Physics and Materials Science, Budapest, Hungary

Resume : The synthesis of graphene-plasmonic metal nanoparticle hybrid materials has been of great interest towards the development of advanced substrates for molecular sensing based on surface-enhanced Raman scattering (SERS). Previously, we investigated the structure [1] and vapour sensing properties [2] of graphene-covered Au nanoparticles. We sandwiched a monolayer CVD graphene flake between two Au nanoparticle layers and measured its structure and SERS capability.: We transferred graphene to Au nanoparticles and deposited a subsequent gold layer on top of graphene. The graphene forms trenches and saddles as lying on the lower nanoparticles therefore the top gold layer follows this unique surface of the corrugated graphene. The Raman response of graphene was significantly enhanced in this hybrid structure. Exposing the sandwich structure to a dilute solution (10-7 M) of rhodamine 6G (R6G), the graphene layer quenched the fluorescent background of R6G by ~60%. We attribute this finding to significant concealment of "hot spots" by the graphene layer. We modified the sandwich structure by removing the graphene interlayer from the Au nanoparticle double-layer using argon-oxygen plasma treatment. Thus, the veiled hot spots became accessible. By this procedure, we could obtain a +35% increase in the Raman signal compared to the simple Au nanoparticle double-layer, which was prepared without a graphene interlayer. Acknowledgements: This work was funded by the National Research, Development, and Innovation Office (NKFIH) in Hungary, through the Grant K-134258. Z.O. acknowledges the János Bolyai Research Fellowship from the Hungarian Academy of Sciences. References: [1] Osváth, Z. et al. The structure and properties of graphene on gold nanoparticles. Nanoscale 7, 5503?5509 (2015). [2] Piszter, G. et al. Vapour sensing properties of graphene-covered gold nanoparticles. Nanoscale Adv. 1, 2408?2415 (2019).

Authors : Adomaviciute-Grabusove, S.*(1), Sablinskas, V. (1), Ceponkus, J. (1), Stankevicius, E. (2), Petrikaite,V (2)., Trusovas, R. (2) Zdaniauskiene, A. (2), Selskis, A. (2), Niaura, G. (1,2)
Affiliations : (1) Institute of Chemical Physics, Faculty of Physics, Vilnius University, Lithuania; (2) Center for Physical Sciences and Technology (FTMC), Lithuania; * lead presenter

Resume : Surface-Enhanced Raman Scattering (SERS) spectroscopy is currently undergoing development in fields of sensing, biochemistry, spectroelectrochemistry. Due to the ability to detect analyte at extremely low concentration and high selectivity of the method, SERS is used in a variety of fields. Tailoring of SERS substrate properties to specific applications is still a priority in the field of SERS. Controllable and reproducible SERS signal can be achieved by creating ordered plasmonic nanostructures or forming of plasmonic nanoparticle aggregates, thus controlling the extent of the enhancement that these nanostructures provide. The laser-ablation technique for plasmonic nanoparticle synthesis holds capacity for production of not only pure and surfactant-free metal nanoparticles but also allows to enrich the nanoparticles with ferromagnetic properties. Such magneto-plasmonic nanoparticles yield possibility to apply magnetic field for creation of highly enhanced electric field in the SERS substrates. In our work, we present magneto-plasmonic hybrid Au/Fe nanoparticles synthesized using the laser-ablation method including evaluation of their capabilities to be applied in SERS spectroscopy. The controlled formation of these nanoparticle aggregates under an external magnetic field has been shown to significantly enhance the Raman scattering of the sample molecules. The magneto-plasmonic nanoparticles were synthesized using 1064 nm 10 ps laser pulses focused to target composed of Au/Fe/Au layers in acetone. Results obtained from scanning electron microscope and X-Ray diffraction spectroscopy reveal a relatively wide size distribution of the synthesized nanoparticles - 10-200 nm for Au core and 2-10 nm for Fe shell. The magnetic response of the nanoparticles was inspected using strong non-uniform magnetic field which enables formation of high SERS enhancement areas on the substrate. SERS performance was evaluated using 4-mercaptobenzoic acid and adenine as probe substances. Our results let us presume that SERS substrate based on magneto-plasmonic nanoparticles with controllable enhancement performance can act as sensor for biomedical applications. Such substrate could be used for analysis of various biological surfaces and could act as sensitive and chemically selective optical biosensors. This project has received funding from the European Regional Development Fund (Project No. 01.2.2-LMT-K-718-03-0078) under grant agreement with the Research Council of Lithuania (LMTLT).

12:15 Discussion    
12:30 Lunch    
Perovskites QDs : Jost Adam, Yogendra Kumar Mishra, Dawid Janas
Authors : Anna Lucia Pellegrino, Francesca Lo Presti, Lorenzo Sirna, Graziella Malandrino
Affiliations : Dipartimento di Scienze Chimiche, Università degli Studi di Catania, INSTM UdR Catania, Viale Andrea Doria 6, I-95125 Catania, Italy.

Resume : All-inorganic halide perovskites (AIHP) represent an emergent class of material, which has many advantages, such as high stability and a great variety of mechanical, magnetic and optical properties. For these reasons are nowadays key materials for many technologies, including photovoltaic solar cells and photocatalytic systems. Unlike the well-known hybrid perovskite counterparts, the AIHP systems do not have any labile or expensive components and show remarkable stability. Furthermore, the entire fabrication process of all-inorganic perovskites can be operated in ambient atmosphere without humidity control systems. Particularly, our attention is devoted to the CsPbBr3 and CsCaF3 systems, which show high stability and excellent performances for photocatalytic and optoelectronic processes. Among the different strategies developed for their syntheses, the solution approach represents the method successfully applied in the present work, allowing to control the stability of the phase and the growth kinetics according to the surface chemical phenomenon and the solubility equilibrium. Herein, we report a novel solution strategy, which represents a facile, one-step, low-temperature and surfactant free approach to the synthesis of Cs-based halide perovskites. In particular, a precipitation approach has been successfully tested for the synthesis of CsPbBr3 microcrystals, taking advantage of the Cs and Pb ?-diketonate compounds as precursors. Furthermore, starting from the analogous Cs and Ca ?-diketonate fluorinated compounds, a combined sol-gel/spin-coating approach has been applied for the fabrication of CsCaF3 perovskite in form of thin films. A careful optimization of the process parameters, such as molar ratio of the starting mixture, aging time and annealing temperature, has allowed to produce, selectively and reproducibly, pure CsPbBr3 and CsCaF3 phases. Structural, morphological and compositional analyses of the final products have been addressed through X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM) and Energy Dispersive X-ray (EDX) analyses. Finally, the CsPbBr3 performances have been deeply studied for photocatalytic degradation processes of organic dye compounds, representing an exceptional candidate as photocatalysts for organic reactions.

Authors : Fanglei Guo1, Stijn Jooken1, Olivier Deschaume1, Wei Yu1, Wim Thielemans2, Carmen Bartic1
Affiliations : 1 Soft Matter and Biophysics, Department of Physics and Astronomy, KU Leuven, 3001 Heverlee, Belgium; 2 Chemical Engineering, Kulak Kortrijk Campus, KU Leuven, 8500 Kortrijk, Belgium

Resume : Colloidal quantum dots exhibit unique photoluminescence (PL) properties, which are size-dependent and temperature-dependent, and therefore have been proposed for nanothermometry applications. Many studies showed that with increasing temperature, the photoluminescence intensity of quantum dots decreases, accompanied by a red spectral shift [1][2]. The mechanisms involved in the temperature dependent PL include a temperature-dependent bandgap energy change and a decrease in quantum yield due to the increase in nonradiative relaxation through thermally activated carrier trapping [3]. Towards the goal of utilizing QDs as nanothermometers in living cells, we are investigating the effect of QDs surface functionalization on their thermosensitivity. For probing temperature changes in living cells, hydrophobic QDs need to be water solubilized to improve their biocompatibility and thermal stability. In this work, CdSe/ZnS QDs and CdSe/CdS QRs were water solubilized either by Poly (styrene-co-maleic anhydride) encapsulation or by silica coating. Afterwards, we calibrated the thermosensitivity of the water transferred QDs under different conditions, i.e., dissolved in solution, surface immobilized and hydrogel encapsulated. In this contribution, we present the results on the effect of surface functionalization of QDs and QRs and measuring conditions on the temperature sensitivity and stability. Keywords: Quantum dots, biological thermometer, silica coating [1] Dai Q, Song Y, Li D, et al. Temperature dependence of band gap in CdSe nanocrystals[J]. Chemical Physics Letters, 2007, 439(1-3): 65-68. [2] Biju V, Makita Y, Sonoda A, et al. Temperature-sensitive photoluminescence of CdSe quantum dot clusters[J]. The Journal of Physical Chemistry B, 2005, 109(29): 13899-13905. [3] Liu TC, Huang ZL,Wang HQ, et al. Temperature-dependent photoluminescence of water-soluble quantum dots for a bioprobe [J]. Analytica Chimica Acta, 2006, 559(1): 120-123.

Authors : Matteo Bombaci, Francesca Lo Presti, Anna Lucia Pellegrino, and Graziella Malandrino
Affiliations : Dipartimento di Scienze Chimiche, Università degli studi di Catania V.le A. Doria 6, 95125 Catania Italy.

Resume : Recently, lanthanum nickelate (LaNiO 3 ), usually indicated as LNO, has attracted lots of attention due to its unusual properties. In fact, it is one of the few perovskites with metallic conductivity in the range 1-1000 K, where the material is not subjected to phase transition. LNO is a perovskite metallic oxide and its resistivity at 300 K is about 1 mΩ cm. It can be adopted as metallic substrate, metallic contact material, protective metallic layer and, due to its lattice parameter of 0.384 nm, as a lattice- matched metallic oxide for perovskite based materials. In particular, lanthanum nickelate is a very promising material for various applications such as the production of a conducting layer for ferroelectric memories and microsensors. Moreover, LNO is also investigated as electrocatalyst, alcohol sensors and as a water splitting anode due to its stability in alkaline solutions and its lower cost if compared with Pt and IrO 2 , usually employed like anodes in photoelectrochemical cells (PEC). In literature, different routes have been proposed to obtain LaNiO 3 films such as pulsed laser deposition (PLD), metalorganic decomposition (MOD), atomic layer epitaxy (ALE), metalorganic chemical vapour deposition (MOCVD), spray pyrolysis and radiofrequency magnetron sputtering. For most of these techniques, single metal precursors of nickel and lanthanum have been employed, but this approach could affect the film production because of the different physico-chemical properties of the precursors like volatility, thermal stability and solubility. In this context, we propose a novel single-source heteronuclear metalorganic complex containing in its structure lanthanum and nickel in the desired 1:1 ratio. For the synthesis of such bimetallic precursor, a fluorinated β-diketone (Hhfa = 1,1,1,5,5,5-hexafluoroacetylacetone) has been used as anionic ligand and a polyether (tetraglyme) completes the coordination sphere of the metal ions. The thermal features of this new precursor have been investigated through thermogravimetric analysis and differential scanning calorimetry, to evaluate thermal stability and volatility. Moreover, the single crystal X-ray diffraction has allowed to determine the coordination of the metal ions. Our product is under investigation for the production of LNO films through vapour or solution approaches.

Authors : D. Torres-Amaris[1], Rafael González-Hernández[2], Aldo. H. Romero[3], and, A. C. Garcia-Castro[1]
Affiliations : [1]School of Physics, Universidad Industrial de Santander, Bucaramanga, Colombia; [2]Departamento de Física y Geociencias, Universidad del Norte, Barranquilla, Colombia; [3]Department of Physics and Astronomy, West Virginia University, Morgantown, United States.

Resume : Magnetically active cations in magnetic antiperovskites, sitting in the corner of the XM6 octahedra, induce an exchange frustration in the [111]-plane. The result is a noncollinear antiferromagnetic ordering such as the Gamma4g and Gamma5g. The Gamma4g is a chiral magnetic ordering, unlike Gamma5g; due to the lack of mirror symmetry, Gamma4g is susceptible to anomalous transport properties. Examples of topological phenomena frequently linked to chirality are the Weyl semimetals (WSM), anomalous Hall conductivity (AHC), and superconductivity. Thus, we propose an AHC controlling in the prototype Mn3NiN antiperovskite through variations in the electronic structure and preservation of the initial space group symmetries. In this work, we theoretically analyze the AHC behaviour under epitaxial compressive/tensile strain in the [111]-plane; feasible by epitaxial growth onto oxide substrates with such preferred crystallographic orientation. Our results indicate a no trivial epitaxial strain to AHC relation; compression/tension does not always induce an enhancing/decreasing response. While tensile strain nearly vanishes the AHC, compression produces initially a grow phase up to a maximum, after which further compression lowers the AHC. Our findings offer a route to characterize the AHC controlling in the manganese nitride antiperovskites family.

Authors : L. Borkovska1, T. Stara1, K. Kozoriz1, E. Nesterenko2, A. Rachkov2, J.-L. Doualan3, T. Kryshtab4
Affiliations : 1 V. Lashkaryov Institute of Semiconductor Physics of NASU, 45 Pr. Nauky, Kyiv, Ukraine; 2 Institute of Molecular Biology and Genetics of NASU, 150 Zabolotnogo Str., Kyiv, Ukraine; 3 CIMAP, CEA-CNRS-ENSICAEN, Normandie Université, 6 Blvd Maréchal Juin, Caen, France; 4 Instituto Politécnico Nacional ? ESFM, Av. IPN, Ed.9 U.P.A.L.M., 07738 Mexico D.F., Mexico

Resume : The interest to luminescent colloidal semiconductor nanocrystals, quantum dots (QDs), is highly motivated by their potential application in bioanalytical chemistry ranging from biomedical imaging to biosensing. In particular, photoluminescence (PL) of water soluble QDs has been found to be pH-dependent, suggesting applications in which QDs serve as pH sensors. The AgInS2 QDs both show high PL quantum yield and comprise of low-toxic elements that is especially important for the in vivo bio-imaging. In this work, the results of investigations of optical properties of the AgInS2/ZnS core-shell QDs synthesized in aqueous media in the presence of glutathione and dispersed in buffer solutions of different pH (3.0-9.0) are presented. The PL spectra of the QDs showed a wide PL band peaked at about 585 nm. It was characterized by the Stokes shift of ~0.7 eV and ascribed to carrier recombination via the levels of intrinsic defects in the QDs. In the PL excitation spectra, an absorption edge shifted to longer wavelengths as the detection wavelength increased. Simultaneously, the PL relaxation times increased from ~280 ns to 880 ns with increasing detection wavelength from 510 to 760 nm. These changes were ascribed mainly to variation of QDs in size. The PL characteristics of the QDs dispersed in buffer solutions varied with pH value. As the pH changed from 3.0 to 9.0, the PL intensity increased by 5 times and the PL band shifted to shorter wavelengths. The largest shift of about 35 nm occurred when pH changed from 3.0 to 4.0. These changes were ascribed to dissociation of ligands from the ZnS outer shell in acidic buffer, resulting in aggregation of QDs and loss of their solubility. The pH dependent increase of PL intensity was accompanied by the increase of PL relaxation times. The effect magnitude depended on the detection wavelength. In particular, the relaxation time increased from 56 ns to 360 ns at 550 nm and remained unchanged at 760 nm. It is proposed that glutathione-capped AgInS2/ZnS QDs may be used as a new type of fluorescence ratiometric pH-sensor or indicator.

14:15 Discussion    
Thin Films Nanotechnology : Yogendra Kumar Mishra, Sugato Hajra, Jost Adam
Authors : Ashish Prajapati Gil Shalev
Affiliations : 1 School of Electrical and Computer Engineering, Ben-Gurion University of the Negev, Israel 2 The Ilse-Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, POB 653, Beer-Sheva 8410501, Israel

Resume : Silicon light funnels are three-dimensional subwavelength structures in the shape of inverted cones with respect to the incoming illumination. Light funnel (LF) arrays can serve as efficient absorbing layers on account of their light trapping capabilities, which are associated with the presence of high-density complex Mie modes. Specifically, light funnel arrays exhibit broadband absorption enhancement of the solar spectrum. In the current study, we numerically explore the optical coupling between surface light funnel arrays and the underlying substrates. We show that the absorption in the LF array-substrate complex is higher than the absorption in LF arrays of the same height (~10% increase). This, we suggest, implies that a LF array serves as an efficient surface element that imparts additional momentum components to the impinging illumination, and hence optically excites the substrate by near-field light concentration, excitation of traveling guided modes in the substrate, and mode hybridization.

Authors : Petroni, E. *(1), Serafini, A. (2), Codegoni, D. (2), Targa, P. (2), Mariani, L. (2), Scuderi, M. (3), Nicotra, G. (3) & Redaelli, A. (1)
Affiliations : (1) STMicroelectronics, TR&D, Agrate Brianza, Italy (2) STMicroelectronics, R2 Physical Lab, Agrate Brianza, Italy (3) CNR-IMM, Catania Headquarter, Strada VIII n.5 Zona Industriale, Catania 95121, Italy * lead presenter

Resume : Ge-rich GST alloys are the most promising materials for phase-change memory (PCM) to fulfill the soldering compliance and the tough data retention requirements of automotive applications. Big efforts have been thus put to engineer those materials and optimize their integration inside the fabrication process of PCM. In this perspective, the physical characterization of the device and the material is instrumental to understand the underlying physics, to improve the process and optimize the interactions between the device, the process, and the material itself. Especially, microscopic investigations have gathered increasing interest, giving detailed descriptions of local material modulations that have a crucial role for cell programming and reliability performances. In this work, a deep analysis of Ge-rich GST microscopic alloy evolution during integration process has been performed, exploiting chemical analysis at Transmission Electronic Microscope supported by a novel statistical data post-processing method. In particular, this statistical-based method is capable to: 1) reduce observed cell-to-cell variability by effectively screening outlier points of STEM chemical maps distribution; 2) introduce a new evaluation metrics to quantify and characterize main compositional properties of integrated Ge-rich GST alloys, allowing trials comparison and detection of not trivial material modulations. The application of this methodology to the study of Ge-rich material behavior in function of back-end-of-line (BEOL) integration has evidenced the exact trend and peculiar features of crystallization phenomenon, highlighting crucial physical points with precise parameters. Moreover, the correspondence between studied physical properties, like degree of crystallization and occurrence of elemental segregation, with the adopted statistical concepts, like dispersion of chemical distribution and outlier population, respectively, has been proved. Thus, the statistical-based methodology has been demonstrated to be robust and to return effective parameters with relevant physical meaning, allowing process study and material optimization. From this point of view, the new proposed statistical-based methodology has been also exploited for process engineering: monitoring introduced metrics an optimized BEOL process has been tuned, minimizing Ge rich GST material segregation.

Authors : Germain Clavier, Shivraj Karewar, Olfa van den Sluis, Johan Hoefnagels
Affiliations : Eindhoven University of Technology (TUe), Mechanical engineering department

Resume : Micro Electro Mechanical Systems (MEMS) have a wide range of applica- tion in various industries, such as optical or acoustic sensors and gyroscopic devices. In the medical field they are typically used in diagnostic devices, an example being echography through sound waves emission and detection. Miniaturised echography devices are interesting for local non-invasive diag- nostics. However, the manufacturing of miniaturized MEMS components is still a technical challenge. Due to the small size of the thin films used within theses components, residual stress influence their performance and should bee controlled. More specifically the residual stresses resulting from the deposi- tion process, i.e., the intrinsic stresses, need to be better understood. The detailed atomistic mechanisms resulting in these intrinsic stresses are still unclear. The relationship between the interacting species, the final atomic structure and the deposition process still needs a detailed comprehension to help in designing reliable microscopic components for miniaturised devices. In this work we present an atomistic model of the deposition process of aluminium atoms on a silicon substrate. The final aim is to reproduce re- latively large structures of aluminium, both amorphous or crystalline and compute local atomic stress. Molecular simulation timescale and space are generally too limited to simulate real physical vapor deposition (PVD) or chemical vapor deposition (CVD), up to the size of relevant layers. But it al- lows to build model layers and give insight into the fundamental mechanisms. We will present new relevant methods allowing to include a large number of atoms at minimum energy positions on top of a growing film surface. From the final systems we will present how we can correlate the obtained struc- ture with the local and global stress seen in the system and how it helps to understand the macroscopic residual stress experimentally observed.

Authors : Rita Maji Julia Contreras-García Elena Degoli Eleonora Luppi
Affiliations : 1. Dipartimento di Scienze e Metodi dell’Ingegneria, Università di Modena e Reggio Emilia, Via Amendola 2 Padiglione Tamburini, I-42122 Reggio Emilia, Italy 2. Laboratoire de Chimie Théorique, Sorbonne Université and CNRS, F-75005 Paris, France 3. Dipartimento di Scienze e Metodi dell’Ingegneria, Università di Modena e Reggio Emilia, Via Amendola 2 Padiglione Morselli, I-42122 Reggio Emilia, Italy Centro Interdipartimentale En & Tech, Via Amendola 2 Padiglione Morselli, I-42122 Reggio Emilia, Italy Centro S3, Istituto Nanoscienze-Consiglio Nazionale delle Ricerche (CNR-NANO), Via Campi 213/A, 41125 Modena, Italy 4. Laboratoire de Chimie Théorique, Sorbonne Université and CNRS, F-75005 Paris, France

Resume : The interaction of grain boundaries (GBs) with inherent defects and/or impurity elements in multi-crystalline (mc-Si) silicon plays a decisive role in their electrical behavior. GBs can create deep-energy states, which induce carrier recombination resulting in a significant reduction of carrier lifetimes [1]. GBs are also preferential segregation sites for atomic impurities [2, 3], and specific to light impurities (e.g. C, O, N, etc.) [4, 5, 6] interaction becomes more complex as under certain conditions they form secondary phase microstructures [4]. Therefore controllable segregation activity is extremely important to minimize the detrimental impact and optimize the efficiency of mc-Si based devices. In this presentation, from first-principles, based on density functional theory (DFT), we will show how the electronic properties of most stable Σ3{111} Si-GB, in the presence of vacancies, are modified by multiple light elements segregation, focussing on O, N, and C mainly [4]. We analyzed the role of these impurities in the presence of vacancy defects finding that the segregation is favorable for those structures which have restored tetrahedral coordination in general. For each structure, we analyzed the density of states and their projection on atoms, the band gaps, the segregation energy, and their correlation to characterize the nature of new energy levels. However, the increasing number of impurities behave differently within GBs for O, C, and N. The inhomogeneous local geometrical distortion due to a Si-vacancy is the main factor that drives the oxygen segregation at GBs [7, 4]. For N, even and odd numbers of impurities lead to different segregated scenarios, whereas for C, mixed combinations have been observed[4]. A comprehensive understanding of the structural condition and impurity agglomerates is necessary, hence in order to highlight more on chemical bonding of their local structures, we have focused on topological analysis obtained from density distribution [8, 9]. A detailed analysis will be discussed for all three impurity elements. Therefore knowing the origin of defined electronic states and their correlation with local coordination would allow the optimization methodology of materials and thus improving corresponding device efficiency. References: 1. S. Wang et al. The Journal of Physical Chemistry Letters 10 (2019). 2. P. Käshammer and T. Sinno, Journal of Applied Physics,118, 9 (2015). 3. D. Zhao and Y. Li, Acta Materialia 168, 52 (2019). 4. R. Maji et. al, The Journal of Chemical Physics, 155:174704, (2021) 5.Y. Ohno et al. Applied Physics Letters 106, 251603 (2015). 6. Y. Ohno et al. Applied Physics Letters 110, 062105 (2017). 7. R. Maji et. al, Acta Materialia, 204, 116477 (2021). 8. A. Savin et. al, Angew. Chem. Int.Ed. Engl., 31:187, (1997). 9. A. D. Becke and K. E. Edgecombe, The Journal of Chemical Physics, 92(9):5397–5403, (1990).

Authors : Perricelli, F.* (1), Fragalà, M. E. (1) & Gulino, A. (1)
Affiliations : (1) Department of Chemical Sciences, University of Catania, and INSTM UdR of Catania, V.le A. Doria 6, 95125 Catania, Italy

Resume : In recent years, the production of microelectromechanical systems (MEMS) dramatically increased in response to the growing request of the newest generation of microelectronic devices employed for the manufacturing of smartphones, tablets, laptops, flexible electronics, and electric vehicles. The use of silicon chips in the new generation of power devices is limited because silicon shows low thermal and electrical conductivity coefficients that determine high power loss and low switching frequencies of the devices. Silicon Carbide (SiC) is a semiconductor employable for the fabrication of the next generation of microelectronic power devices, due to its excellent physico-chemical properties such as wide bandgap, high thermal conductivity, high chemical resistance, high breakdown electric field, high electron saturation velocity and high thermal resistance.[1] Trench SiC metal-oxide-semiconductor field-effect transistor (MOSFETs) or U-MOSFETs, due to the U-shape of the trench, reduce the conduction and switching losses, compared to the existing planar SiC MOSFET. In the U-shape configuration, the gate electrode is buried into the trench, and this allows the elimination of the junction field-effect transistor (JFET) region that increases the current flow width, the channel density and reduces the electrical resistance. In addition, U-MOSFET can be fabricated in a smaller surface area than the planar MOSFET, since the MOS channel is oriented perpendicular to the surface. In fact, the cell pitch, that is the distance between two source terminals, is smaller with respect to the planar MOSFET configuration. These factors enable the increase of the number of devices packed in the same chip area.[2-3] Therefore, the aim of this work was the production of silicon carbide trenches by an SF6/O2/Ar/He inductively coupled plasma reactive ion etching (ICP-RIE) process, using an interferometric algorithm to control both the end-point and trench depth. The fabrication process was characterized by suitable etch rate values, depth uniformity between the wafer centre and edge, absence of microtrenches and collateral contaminants, no crystallographic damage of the trench sidewalls, and low surface roughness. The morphological and structural characterization of the silicon carbide trench was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). [1] She, X.; Huang, A. Q.; Lucía, Ó.; Ozpineci, B., IEEE Trans. Ind. Electron. 2017, 64, 8193– 8205 [2] Osipov A. A.; Iankevich G. A.; Speshilova A. B.; Osipov A. A.; Endiiarova E. V.; Berezenkos V. I.; Tyurikova I. A.; Tyurikov K. S.; Alexandrov S. E., Sci. Rep. 2020, 10, 19977 [3] Sung, H.-K.; Qiang, T.; Yao, Z.; Li, Y.; Wu, Q.; Lee, H.-K.; Park, B.-D.; Lim, W.-S.; Park, K.-H.; Wang, C., Sci. Rep. 2017, 7, 3915

Authors : Kolosovsky, D.A., Dmitriev, D.V., Ponomarev, S.A., Toropov A.I., Zhuravlev K.S.
Affiliations : Rzhanov Institute of Semiconductor Physics, Novosibirsk 630090, Russian Federation

Resume : InP(001) substrates are used to make heterostructures (HESs) by molecular-beam epitaxy (MBE), which are used to make lasers, electro-optical modulators, and high-power microwave photodiodes. The growth of the HES begins with the removal of the substrate amorphous oxide layer. The oxide layer on the InP substrate is removed by high-temperature annealing in an As flux. During the annealing the substrate surface chemical composition changes with the formation of an InPAs solid solution and InAs islands [1]. The lattice mismatch between InP and InAs leads to the appearance of defect nucleation centers in the HES, which leads to changes in the initial stages of nucleation and subsequent processes of epitaxial growth. The purpose of the work is to study the formation of InAs islands on the InP(001) surface during high-temperature annealing in arsenic flux. We used epi-ready InP(001) substrates from AXT. Annealing was carried out in the MBE system Riber Compact 21T. The annealing temperature was varied from 480-540 °C and the arsenic flux from 8×10-6-2.5×10-5 Torr. The annealing ended with the formation of a (4×2) structure in the diffraction pattern. The surface morphology of the samples was studied by atomic force microscopy on a Bruker Multimode 8 microscope. An exponential increase in the density of InAs islands from 4.4×107 cm?2 to 1.8×108 cm?2 was observed with an increase in the annealing temperature and arsenic flux. The islands were elongated along the [1?1 0] direction and had a lateral size from 65 nm to 130 nm along this direction. The lateral size of InAs islands along the [1 1 0] direction was from 40 nm to 90 nm. The total surface area occupied by InAs islands does not exceed 1.5% of the substrate area. An increase in the annealing temperature leads to a more uniform distribution of InAs islands over the surface. The lowest density of islands and the area occupied by them were observed at an annealing temperature of 480 °C and an arsenic flux of 8×10-6 Torr. The reason for these islands appearance is the desorption of phosphorus and the segregation of indium. The substrate annealing temperature is higher than the dissociation temperature of the InP surface. Appropriately, an excess concentration of indium adatoms is formed on the surface. Kink of the atomic step is the most energetically favorable position and the adatoms attaching to the kink is most probable. As a result, indium and arsenic adatoms, in the flux of which the annealing process occurs, attach to the kink. Subsequently, an InAs nucleus are formed and grow up [2]. References [1] D.V. Dmitriev, et al. Surface Science 710 (2021) 121861. [2] D.A. Kolosovsky, et al. IEEE 22nd International Conference of Young Professionals in Electron Devices and Materials (EDM) (2021) pp. 17-21. Poster presentation preferred

Authors : Youya Wagatsuma1, Rena Kanesawa1, Md. Mahfuz Alam1.2, Kazuya Okada1, Michihiro Yamada3, Kohei Hamaya3, and Kentarou Sawano1
Affiliations : 1Advanced Research Laboratories, Tokyo City University, 8-15-1 Todoroki, Setagaya-Ku, Tokyo 158-0082, Japan; 2Department of Physics, University of Barishal, Barishal-8254, Bangladesh; 3Center for Spintronics Research Network, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan

Resume : Recently, it has been shown that Ge and SiGe with (111) orientation are very attractive for applications to spintronic devices because high quality ferromagnetic materials can be epitaxially grown on the Ge(111)[1]. Moreover strain introduction is expected to improve the spin lifetime of electrons. Previously we studied surface morphologies and strain states for the strained SiGe(111) layers grown on Ge(111), and found that cracks and related ridge roughness appear on the surfaces[2]. Moreover, we have demonstrated that such crack formation can be totally suppressed by patterning of Ge-on-Si substrates [3]. In this work, we study mechanisms of the crack formation by means of comparing strained SiGe layers grown on Ge-on-Si and Ge substrates with patterning. In experiments, the crystal growth was carried out with solid source molecular beam epitaxy. The Ge-on-Si(111) was fabricated using the so-called two-step growth method. 40 and 650 nm thick Ge layers were subsequently grown on a Si(111) substrate at 400 and 700 °C, respectively, followed by annealing at 800 °C for 10 min. Subsequently, the 80 µm × 80 µm square mesa-patterning of the Ge-on-Si(111) and Ge(111) substrates were performed by the standard photolithography process. The etched depth outside of mesa was varied from 350 to 690 nm. Depending on the etched depth, partially etched Ge-on-Si (PE-GOS), fully etched Ge-on-Si (FE-GOS) and partially etched Ge substrates (PE-Ge) were prepared. Then strained SiGe layers with thicknesses from 200 to 250 nm were grown on these templates at 350 °C. It was found that crack formation was completely suppressed for the SiGe layers grown on the FE-GOS(111) substrate. By contrast, high-density cracks appear on the mesa for SiGe layers grown on PE-GOS(111) and PE-Ge(111) substrates where some cracks were connected across the mesa edges. These results indicate that cracks generated outside of the mesa area propagated into the mesa area and that there are crack generation sources in Ge layers which remain outside of the mesa after the partial etching. For FE-GOS, such crack generation sources were completely removed by the full etching of Ge and crack-free strained SiGe layers can be fabricated, indicating that the patterning method is promising for strained SiGe based spintronic device applications. This work was supported in part by Grant-in-Aid for Scientific Research (Nos. 19H02175, 19H05616, 20K21009) from MEXT, Japan [1] K. Hamaya et al., J. Phys. D: Appl. Phys. 51, 393001(2018). [2] Md. M. Alam et al., Appl. Phys. Express 12, 081005 (2019). [3] Y. Wagatsuma et al., Appl. Phys. Express 14 025502(2021)

16:45 Discussion    
Start atSubject View AllNum.
Photonics : Jost Adam, Yogendra Kumar Mishra, Ayan Chaudhuri
Authors : Francesco Reda *(1), Marcella Salvatore (1,2), Fabio Borbone (3,4), Pasqualino Maddalena (1,2,4), Antonio Ambrosio (4), Stefano Luigi Oscurato (1,2,4)
Affiliations : (1) Department of Physics “E. Pancini”, University of Naples “Federico II”, Complesso Universitario di Monte Sant’Angelo, Via Cintia, 80126 Naples, Italy; (2) Centro Servizi Metrologici e tecnologici Avanzati (CeSMA), University of Naples “Federico II”, Complesso Universitario di Monte Sant’Angelo, Via Cintia 21, 80126, Naples, Italy; (3) Department of Chemical Sciences, University of Naples “Federico II”, Complesso Universitario di Monte Sant’Angelo, Via Cintia, 80126 Naples, Italy; (4) CNST@POLIMI—Fondazione Istituto Italiano di Tecnologia, Via Pascoli 70, 20133 Milan, Italy;

Resume : Amorphous azopolymer thin films exhibit the formation of photoinduced surface reliefs as result of a macroscopic mass migration phenomenon, originated at molecular level by the UV-visible light-induced isomerization cycles of the azobenzene molecules embedded in the polymeric chain. Relief formation occurs below the glass transition temperature of the azopolymer and produces surface patterns that are stable over time. Their geometry is strongly dependent on the intensity distribution, polarization and wavefront of the incident light. This property has made them highly interesting in many research fields of photonics and material science. Additionally, as the structuring process is intrinsically reversible, the pristine state of the surface can be restored both thermally or optically, without destroying or altering the polymeric chain. For this reason, this class of materials can be used to replace common photoresists in order to obtain a single step all-optical reversible lithographic structuration. Full control on the tridimensional shape of photoinduced surface structures on azopolymer films can be obtained by tailoring the spatiotemporal distribution of light intensity on the free surface of the polymer. Here, I will overview recent advances in the design and fabrication of azopolymer light-induced reliefs obtained with an illumination scheme based on computer generated holograms. This technique allows the generation of grayscale intensity patterns on the azopolymer surface by phase modulating a laser beam through a computer controllable spatial light modulator. Almost arbitrary geometries in the light distribution can be achieved in this way, enabling accurate and fast control over all the lithographic parameters needed for the realization of reversible diffractive optical elements (DOEs) on the azopolymer. With this versatile optical scheme, flat optical components, modulating incident light wavefront within thickness comparable with the light wavelength, are realized and dynamically tuned by accurately engineering the azopolymer surface according to the desired optical functionality. In addition, the possibility to in-place erase and rewrite the polymer surface with completely different geometry is here used to design dynamical optical systems based on shapeshifting diffractive gratings, lenses and holograms that represent a valid prospective for the realization of next generation optical systems, where flat and dynamic optical devices will needed.

Authors : Kertész, K.*(1), Piszter, G.(1), Baji, Zs.(1), Bálint, Zs.(2) & Biró, L.P(1)
Affiliations : (1)Institute of Technical Physics and Materials Science, Centre for Energy Research, Konkoly-Thege Miklós út 29-33., 1121 Budapest, Hungary; (2)Hungarian Natural History Museum, Baross utca 13., 1088 Budapest, Hungary; * lead presenter

Resume : Chemical (pigmentary) coloration of butterflies is often supplemented by physical color generated by photonic nanostructures. These nanoarchitectures (often complex 3D structures) - characteristic for a given species - are located in the lumen of the wing scales and exhibit wavelength ranges in which light propagation is forbidden. It is crucial to establish well-defined measurement methods for the unambiguous characterization and comparison of colors generated in such a complex manner. Owing to the intricate architecture ordered at multiple levels (from centimeters to tens of nanometers), the precise quantitative determination of butterfly wing coloration is not trivial. We present an overview of several optical spectroscopy measurement methods and illustrate techniques for processing the obtained data, using the species Polyommatus bellargus as a test case, the males of which exhibit a variation in their blue structural color. The benefits and drawbacks of these optical methods are discussed and compared [1]. Furthermore, the origin of the color differences is explained in relation to differences in the wing scale nanomorphology revealed by electron microscopy. As the photonic crystal structure determines the wing color, by induced alteration of size or refractive index of the building materials, it is possible to tune the resulting color. In order to obtain information on multiple types of structures, single crystalline, polycrystalline, thin film, and pepper-pot-type photonic nanoarchitectures of different butterflies were investigated, and also a bioinspired multilayer of silica spheres as a purely physical model. By atomic layer deposition (ALD) (additive) the color of all nanoarchitectures was red shifted and by plasma etching (subtractive) was blue shifted in a controllable way. It was demonstrated on butterfly wing scales with open 3D nanostructures that two structural modification methods offer fine and controllable tuning of the reflected light spectrum, using completely different principles and instrumentation [2]. In terms of surface chemistry, one builds up the substrate with a conformal, chemically inert/or chemically active coating, and the other removes the original superhydrophobic superficial layer. Both methods keep the benefit of these structures possessing large surface area. They open new routes to potential applications [3]. This research was funded by the Priority Project of the Centre for Energy Research and by the TKP2021-NKTA-05. [1] Kertész, K., Multi-instrumental techniques for evaluating butterfly structural colors: A case study on Polyommatus bellargus (Rottemburg, 1775) (Lepidoptera: Lycaenidae: Polyommatinae) Arthropod Struct. Dev. 61 (2021) [2] Kertész, K., Additive and subtractive modification of butterfly wing structural colors Colloids Interface Sci. Commun. 40 (2021) [3] Piszter, G., Spectral tuning of biotemplated ZnO photonic nanoarchitectures for photocatalytic applications, submitted

Authors : Elena Cabello-Olmo, Gabriel Lozano, Hernán Míguez
Affiliations : Institute of Materials Science of Seville (Spanish National Research Council - University of Seville)

Resume : Rare-earth phosphors are the materials in which solid-state lighting technology is based. Nevertheless, their large crystal size hinders the control over the emitted light. The synthesis of nanoparticles made of such materials and the processing of them into transparent thin films open new routes to manipulate the way the light is generated. In this talk, we show that the integration of nanophosphor-based transparent films into photonic structures lead to a precise control over the chromaticity and directionality of these nanosources avoiding chemical modification in the synthesis route and thus maintaining the stability of the nanoparticles. To do so, we start with the optimization of efficient and bright transparent films processed through wet methods. [1,2] Then, we carry out different approaches to modify their optical properties. In particular, nanophosphors films are embedded in systems based on one dimensional photonic crystals. Intense red emission at targeted directions and particular colors are attained when nanophosphor light emission is coupled to resonant modes supported by the photonic structures. [3,4] Furthermore, we explore the outcoupling of the emitted light when the surface of nanophosphor films is periodically patterned via soft-lithography. As a result, the direct nanoimprint of the films leads to an enhanced emission at selected directions employing inexpensive procedures.[5] References: [1] Geng, D., Lozano, G., Calvo, M. E., Núñez, N. O., Becerro, A. I., Ocaña, M., & Míguez, H. (2017). Photonic tuning of the emission color of nanophosphor films processed at high temperature. Advanced Optical Materials, 5(13), 1700099. [2] Geng, D., Lozano, G., & Míguez, H. (2018). Highly efficient transparent nanophosphor films for tunable white-light-emitting layered coatings. ACS applied materials & interfaces, 11(4), 4219-4225. [3] Geng, D., Lozano, G., Calvo, M. E., Núñez, N. O., Becerro, A. I., Ocaña, M., & Míguez, H. (2017). Photonic tuning of the emission color of nanophosphor films processed at high temperature. Advanced Optical Materials, 5(13), 1700099. [4] Geng, D., Cabello-Olmo, E., Lozano, G., & Míguez, H. (2019). Tamm plasmons directionally enhance rare-earth nanophosphor emission. ACS photonics, 6(3), 634-641. [5] Cabello‐Olmo, E., Molet, P., Mihi, A., Lozano, G., & Míguez, H. (2021). Enhanced Directional Light Extraction from Patterned Rare‐Earth Phosphor Films. Advanced Optical Materials, 9(2), 2001611.

Authors : Anna Capitaine, Beniamino Sciacca
Affiliations : Aix-Marseille Univ, CINaM; CNRS, CINaM

Resume : High-quality monocrystalline materials and nanostructures are key to high-efficiency optoelectronic devices (Polman et al., Science, 2016), plasmonic materials (Wu et al., Adv Mater, 2014) and metasurfaces (Koenderink et al., Science 2015). A large variety of materials can be synthesized at low temperature in solution as colloidal single crystals, combining the advantages of high-quality material, low-cost fabrication, and potential for large area integration into nanophotonic and plasmonic devices. Unfortunately, they have so far been limited to Platonic solid shapes. This is in stark contrast to nanostructures obtained by top-down methods, that offer almost unlimited capability for plasmon resonance engineering, but present poor material quality and have doubtful perspectives for scalability, limiting nanostructured monocrystalline materials to niche applications. It has been demonstrated that single-crystal silver nanocubes, grown in solution phase, could be used as building blocks for the fabrication of continuous monocrystalline 1D nanostructures through epitaxial welding of adjacent nanocubes (Sciacca et al, Adv Mater., 2017). We show that this approach can be used as a general method to fabricate 1D and 2D monocrystalline gold (Au) plasmonic arrays of arbitrary shapes for the first time, combining the best of different worlds (highest material quality, arbitrary geometry, bottom-up, low cost). Monodisperse Au single-crystal nanocubes are first synthesized in solution at room temperature. Next, using capillary forces they are self-assembled in a polydimethylsiloxane (PDMS) mould containing pre-defined 1D and 2D nanoscale patterns, in a closely packed configuration, with individual nanocube subunits lying face-to-face. Then, using a novel approach of simultaneous oxidative dissolution and growth, assemblies of nanocubes are epitaxially connected and transformed into continuous monocrystalline nanostructures in the time scale of a few minutes at low temperature. The chemical framework for nanocube epitaxy is thoroughly investigated with a set of control experiments and operando optical characterization on a nanocube dimer model system is used to unveil the mechanism with atomic scale resolution. This enables us to control morphology and faceting of the monocrystalline nanostructures. We use high-resolution transmission electron microscopy and electron diffraction to provide evidence for epitaxy, and compare optical spectra of individual nanoantennas and arrays to FDTD simulations to show that materials of the highest quality are obtained. Finally, we show that such complex continuous Au nanostructures of arbitrary shapes can be transferred from PDMS to various substrate by contact printing. This paves the way for swift integration of nanophotonic surfaces of the highest quality in optical and optoelectronic devices and architectures that are incompatible with classic nanopatterning strategies such as perovskite layers.

Authors : K. Papadopoulos 1, D. Tselekidou 1, V. Kyriazopoulos 1,2, S. Kassavetis 1, A. K. Andreopoulou 3, K. Andrikopoulos 3, J. K. Kallitsis 3, M. Gioti 1
Affiliations : 1 Nanotechnology Lab LTFN (Lab for Thin Films – Nanobiomaterials – Nanosystems – Nanometrology) Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece; 2 Organic Electronic Technologies P.C. (OET), Antoni Tritsi 21B, GR-57001 Thessaloniki, Greece; 3 Department of Chemistry University of Patras, University Campus, Rio-Patras GR-26504, Greece

Resume : Nowadays needs necessitate thinking beyond conventional rigid and planar lighting and paving the way for bendable lighting, such as light-emitting devices on substrates that can be bent, flexed or even stretched like polyethylene terephthalate (PET), other plastic-like materials and even textiles. In the past decade, there has been dramatic progress in the field of solution-processed organic light-emitting diodes (OLEDs). Along these lines of research in both academia and industry, there is still a great demand to develop blue-light emitting polymers on the path toward white emission and full-color polymer displays. While a stable blue Polymer LED (PLED) is still a challenge for polymer scientists, it is hard to achieve a balanced charge injection because of the large bandgap between the HOMO and LUMO energy levels. In this study, we compared promising lab-scale blue-emitting polymer bearing Carbazole moiety with commercially available Polyfluorene derivatives in terms of film-forming ability, emission characteristics and color purity. The spin coating technique was implemented to produce functional layers, including the hole transport layer and emitting layer. The optical and photophysical properties of the solution-processable thin films were thoroughly studied via NIR-Vis-far UV Spectroscopic Ellipsometry (SE) and Photoluminescence (PL) respectively, whereas the structural characteristics were examined by Atomic Force Microscopy (AFM). Subsequently, blue light OLED devices were fabricated, and they were evaluated using Electroluminescence (EL). From the analysis of the electrical data, valuable information was obtained for the different current-density characteristics under different bias voltage regimes. Emission bandwidths, color coordinates and luminance were also derived in order to evaluate the devices’ stability. Finally, the printability of the polymer films to flexible substrates was investigated using slot-die coating processes. Acknowledgments This research has been co‐financed by the European Regional Development Fund of the European Union and Greek national funds through the Operational Program Competitiveness, Entrepreneurship and Innovation, under the call RESEARCH – CREATE – INNOVATE (project code: T1EDK-01039).

Authors : Pariksha Malik, Santanu Ghosh, G.V. Prakash, Pankaj Srivastava
Affiliations : Department of Physics, Indian Institute of Technology Delhi, New Delhi, India

Resume : It is vital to enhance solar cell efficiency in order for photovoltaic power generation to be a realistic alternative to the global energy challenge. Photovoltaics (PVs) will be crucial in transitioning to a fully renewable energy economy. Increasing power conversion efficiency (PCE) is critical because it reduces the amount of energy-intensive materials used, such as crystalline silicon (c-Si), and thus decreases energy payback. Enhancing the amount of sunlight that reaches the photo-conversion layer is one approach that could be taken. In recent years, femtosecond lasers have demonstrated promising applications in bio, energy, and aerospace. As previously stated, multiphoton phenomena and nonthermal processes are at the heart of femtosecond laser surface modification. With a minimum of flaws, this type of laser can form extremely uniform periodic structures on the nano- and microscale. On surfaces of various materials, such as titanium, stainless steel, silicon, aluminum alloys, and others, beautiful self-assembled structures are produced. To increase solar cell efficiency, for example, femtosecond lasers are used to alter the surfaces of solar panels [1,2]. Femtosecond lasers are used in Mazur's group to create periodic structures on black silicon with nano- and micro-size features [3,4]. Sub-micron scale three-dimensional microstructures could be formed by influencing the laser beam straightforward trying to focus radiation or interference, and also the scanning rates and routines. To pattern Silicon Nitride (SiNx), various techniques have been developed, such as photolithography with wet etching in acidic solutions [5]. However, this method necessitates a number of process steps, as well as costly equipment and toxic chemicals. To fabricate fine structures with well-defined edges on SiNx thin films, a non-lithographic or direct patterning strategy must be developed. Laser ablation is the expulsion of materials from a substrate by direct absorption of laser energy, which can yield the required combination of narrow and clean patterning due to their advantage in regionalized heating and material expulsion. Research teams studied the interaction of femtosecond laser pulses with various materials such as silicon, Al, and ITO in the presence of air, water, and sulfur hexafluoride (SF6) [4] but no one is not studied direct laser writing on SiNx till now as per my knowledge. The micro/nanostructures over silicon nitride films were created using a femtosecond amplifier laser system (800 nm, 120 fs, 1 kHz). For the micro/nano fabrication procedure, an amplifier that generates a linearly polarized Gaussian beam with pulse energy of 4.0 mJ/pulse and pulse width of 120 fs at a maximum repetition rate of 1 kHz and a central wavelength of 800 nm was used. An x-y galvo was used to focus and scan the laser beam in a line pattern on the film surfaces. The Galvo scanner was designed to travel at a speed of 0.1 mm/s to ensure faster fabrication as well as the stability of silicon nitride over Si substrate during laser pulse interaction with film. During optimization at higher speeds, irregular patterns were observed. The focused spot had a diameter of about 10 m, defined by an intensity drop to 1/e2 of the maximum value. For single pulse energy, pulse repetition rate, laser scanning speed, and line spacing, the laser processing parameters used to fabricate the hyper-hierarchical structure are 75 mW, 1kHz, 0.1 mm s-1, and 100 m, respectively. The current work reveals the fabrication of micro/nanostructures on SiNx over silicon substrates using femtosecond laser writing in an air medium. These micro/nanostructures have a diameter of about 300-400 nm and resemble structures. It has discovered that micro/nanostructures structures form as a result of the interaction of femtosecond pulse-induced plasma with a SiNx/Si substrate. The absorption of intense light in a thin SiNx/silicon layer produces a plasma at the SiNx-air interface. The plasma then equilibrates with the surrounding air and SiNx, resulting in a layer of molten silicon on the surface. Furthermore, these fabricated structures have been characterized using scanning electron microscopy (SEM), Raman spectroscopy, cross-section FESEM, and a UV-VIS spectrophotometer for optoelectronics applications such as Photovoltaic and Surface Enhanced Raman Spectroscopy (SERS). In the wavelength ranges of 400–800 nm, and 200-1000 nm, respectively, average specular reflectance of 2.82 percent, and 5% are attained, with an average absorptance of 95 percent within 0.2–1 m. The material easiness, patterning versatility, boosting capability, structural reliability, and self-cleaning quality can meet the necessary criteria for useful light-harvesting applications. References: [1] McDonald J P, Mistry V R, Ray K E, Yalisove S M, Nees J A and Moody N R 2006 Femtosecond-laser-induced delamination and blister formation in thermal oxide films on silicon (100) Applied Physics Letters 88 153121 [2] Feng T, Chen G, Han H and Qiao J 2021 Femtosecond-Laser-Ablation Dynamics in Silicon Revealed by Transient Reflectivity Change Micromachines 13 14 [3] Dalili A, Tan B and Venkatakrishnan K 2010 Silicon wafer surface patterning using femtosecond laser irradiation below ablation threshold Optics and Lasers in Engineering 48 346–53 [4] Vorobyev A Y and Guo C 2013 Direct femtosecond laser surface nano/microstructuring and its applications Laser & Photonics Reviews 7 385–407 [5] Hoheisel M, Mitwalsky A and Mrotzek C 1991 Microstructure and etching properties of sputtered indium—tin oxide (ITO) Physica Status Solidi (a) 123 461–72 [6] Stratakis E, Zorba V, Barberoglou M, Fotakis C and Shafeev G A 2009 Femtosecond laser writing of nanostructures on bulk Al via its ablation in air and liquids Applied Surface Science 255 5346–50

09:45 Discussion    
Advanced Electronic Devices : Yogendra Kumar Mishra, Veronika Zadin, Dawid Janas
Authors : Sreetosh Goswami
Affiliations : Centre for Nanoscience and Engineering (CeNSE), Indian Institute of Science (IISc), Bangalore

Resume : Artificial Intelligence (AI) is a concept that has seen many hype cycles arrive and fade as we have become overly impressed by our computing machines and then dismayed by our realization of the complexity of what brains actually do. In recent years, we might believe that the age of AI has finally arrived as algorithms beat human champions at complex games and the champions retire in frustration. However, a look into the backroom reveals that the machines that run these algorithms require kilowatts of power to operate, and the amount of preparation and training of the algorithms is long and extremely costly. When it comes to functions like intelligence, cognition, and decision making, any of today’s best computing systems is outperformed by the brain by orders of magnitude both in terms of energy and space efficiency. The primary reason for our shortcoming is that we are using conventional passive circuit elements to emulate a highly non-linear dynamic operating system of a brain that operates on the verge of chaos. In this talk, I shall introduce a new generation of molecular circuit elements [1-3] that can capture complex, reconfigurable, dynamic logic in nano-scale material properties and can also be poised on the verge of instability. These devices could offer an optimal platform for emulating brain’s functions. [1] Nature, 2021, 597(7874), 51-56 [2] Nature nanotechnology, 2020, 15(5), 380-389 [3] Nature materials, 2017, 16(12), 1216-1224

Authors : Krishna Rudrapal, Venimadhav Adyam and Ayan Roy Chaudhuri
Affiliations : Materials Science Centre, Indian Institute of Technology Kharagpur, 721302 Kharagpur, West Bengal, India

Resume : Resistive switching (RS) in metal oxides which offer self-compliance, and multiple resistance states without the requirement of any high voltage forming step hold the potential of application in selector less high density resistive random access memory devices. Typically, operation of metal oxide based RS devices require integration of additional oxide layers or circuit elements to achieve current compliance and complicated device architecture for high density memory applications. It is well known that oxygen vacancies (VOs) often play deterministic role in the RS mechanism of metal oxides. An in-depth investigation of the RS properties in VOs engineered WO3-x thin films suggest that optimization of VOs concentration in WO3 holds promise of realising stable bipolar resistive switching. We demonstrate self-compliance, and multi-level RS that does not require high voltage forming in a single layer non-stoichiometric WO3-x. This study suggests VOs in the pristine WO3-x layer leads to its forming-free filamentary switching characteristics, whereas reversible formation and annihilation of an oxygen-rich region in the filament at WO3-x/electrode junction has been envisaged to be responsible for self-compliance set and voltage controlled multiple reset resistance states. Our results demonstrate non-stoichiometric WO3-x with an active metal/oxide interface permeable to reversible oxygen migration can pave the way of producing high density, reliable RRAM devices.

Authors : Anamika Ashok, Subin P S, M K Jayaraj, Asha A S
Affiliations : Anamika Ashok - Nanomaterials for Emerging Solid state technology (NEST) laboratory, Department of Physics, Cochin University of Science and Technology; Subin P S- NanoPhotonic and OptoElectronic Devices (NPOED) laboratory, Department of Physics, Cochin University of Science and Technology; Dr. Asha A S- Nanomaterials for Emerging Solid state technology (NEST) laboratory, Department of Physics, Cochin University of Science and Technology, Centre of Excellence in Advanced Materials, Cochin University of Science and Technology; Prof M K Jayaraj - Calicut University

Resume : Two dimensional transition metal carbides/nitrides, MXenes have attracted immense attention in energy storage and optoelectronic device applications, due to their excellent conductivity. The potential use of the compound in nanoelectronic applications like resistive switching is least explored. The utilisation potential of the material is limited by the hazardous HF etching and mixed acid etching routes of synthesis. The alternative milder etching routes fail to convert the MAX phase fully into MXene, hence suppressing the inherent properties of MXene. Attempts to synthesize MXene via temperature assisted routes like hydrothermal synthesis increases the risks of oxidation. The present work synthesizes MXene via milder in situ HF etching technique, with a simple modification using a base in the dilution process, to improve the properties of the material. Liquid phase exfoliated titanium carbide (Ti3C2Tx) MXene synthesized through novel base assisted in situ HF etching technique, exhibiting enhanced structural, electronic and optical properties was used for resistive switching applications. The delaminated stable colloids obtined by sonication of multi-layered MXene were ultrasonic spray coated onto ITO and glass substrates. The structural properties were confirmed by the appearance of characteristic (002) plane diffraction peak of MXene with significant intensity in the XRD patterns of the multilayer powder and MXene thin film. XRD analysis also confirmed successful removal Al, by the disappearance of (104) plane diffraction peak. The morphology was analysed using SEM analysis, to obtain the typical open accordion MXene, even with a milder etching route. The functional groups were identified with XPS analysis and the optical properties were studied using UV Visible absorbance spectrum. The absorbance spectrum of the delaminated MXene colloids exhibited characteristic plasmonic peak in the NIR region and that of the thin film had a transparency of about 50% in the visible rnge. The colloidal stability was studied over a course of 40 days and was further confirmed using DLS to rule out any possibility of aggregation detrimental to colloid stability. ITO/Ti3C2Tx/Cu devices were fabricated and the device exhibited bipolar resistive switching characteristics. The stability of the ON and OFF states of the device were also studied. A simple and scalable synthesis technique has been utilised to fabricate high quality titanium carbide MXene thin film, suitable for memristor applications.

Authors : Avik Sett, Shatavisha Biswas, Tarun Kanti Bhattacharyya
Affiliations : Department of Electronics and Electrical Communication Engineering, IIT Kharagpur, Kharagpur, India; Department of Electronics and Electrical Communication Engineering, IIT Kharagpur, Kharagpur, India; Department of Electronics and Electrical Communication Engineering, IIT Kharagpur, Kharagpur, India

Resume : Due to enormous increase in industrial activities, toxic metallic pollutants such as As, Pb, Cd and Hg have gained worldwide concern due to their deleterious environmental and biological effects. These heavy metals are non-biodegradable and can easily attach with the food chain of the environment which later puts severe threat to human health. Due to fatal consequences of these pollutants in public health, many organizations have determined the maximum permissible amount of the ions in food, drinking water, blood, etc. Based on the Environmental Protection Agency (EPA), the safety limits of mercury, lead, cadmium and arsenic in drinking water are 2, 15, 5 and 10 parts per billion (ppb) respectively. The repletion of Hg2+ in human body can cause ailments in vital organs, disorders in the nucleic acid function, defects in the immune system, and even death. It is a very challenging task to detect As3+ ions in the presence of other contaminants in water. Hence development of accurate and sensitive analytical techniques for effective monitoring and accurate measurement of these toxic ions are getting considerable attention worldwide. Conventional analytical techniques such as AAS/AES, ICP-MS, ASV are time consuming, requires expensive equipment and incur complex measuring procedures. Alternatively, several sensors have been developed for the detection of As3+ ion, such as colorimetric, fluorescent, electrochemical, and surface-enhanced Raman scattering. Despite these advancements, novel sensors with simple operation, low cost, portable analytical platform for user friendly analysis are still needed. In this work, curcumin functionalized zinc oxide nanorods (Cur-ZnO) were used as an electrical sensing platform for highly selective and sensitive As3+ detection. Zinc oxide nanorods were synthesized using solvothermal approach and attachment of curcumin to ZnO nanrods were obtained through an in-situ approach. Field emission scanning electron microscopy (FESEM), High resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) and Ultraviolet-visible (UV-Vis) absorbance analysis were done to confirm the attachment of curcumin sheets to ZnO nanorods. The sensing platform was fabricated in a novel staggered gate-field effect transistor (SG-FET) configuration with Cur-ZnO as the sensing layer. A high-k dielectric (hafnium oxide) was used as gate dielectric and aluminium was used as gate metal. The sensor performance towards As3+ was investigated electrically in presence of other competitive contaminants. The sensor was found to be highly selective towards As3+ in presence of Pb2+, Hg2+,Cd2+, Na+ and Cu2+. The interaction of As3+ ions with the sensing layer was also studied using UV-Vis and PL spectrophotometer. The sensitivity of the sensor was seen to improve by tuning the gate voltage. Our work suggests that Cur-ZnO based staggered gate-field effect transistor (SG-FET) are promising towards development of low-cost, portable and real-time room temperature heavy metal ion detectors.

11:30 Discussion    
2D Materials and Devices : Sreetosh Goswami, Yogendra Kumar Mishra, Dawid Janas
Authors : Erik Piatti, Adrees Arbab, Francesco Galanti, Tian Carey, Luca Anzi, Dahnan Spurling, Ahin Roy, Ainur Zhussupbekova, Kishan A. Patel, Jong M. Kim, Dario Daghero, Roman Sordan, Valeria Nicolosi, Renato S. Gonnelli, Felice Torrisi
Affiliations : Erik Piatti; Francesco Galanti; Dario Daghero; Renato S. Gonnelli; Department of Applied Science and Technology, Politecnico di Torino, I-10129 Torino, Italy. Adrees Arbab; Jong M. Kim; Department of Engineering, University of Cambridge, Cambridge CB3 0FA, UK. Adrees Arbab; Tian Carey; Felice Torrisi; Department of Chemistry, Molecular Sciences Research Hub, Imperial College London, White City Campus, Wood Lane, London, W12 0BZ, UK. Luca Anzi; Kishan A. Patel; Roman Sordan; L-NESS, Department of Physics, Politecnico di Milano, I-22100 Como, Italy Dahnan Spurling, Ahin Roy, Ainur Zhussupbekova; Valeria nicolosi; Trinity College Dublin, Dublin 2, Ireland. Felice Torrisi; Dipartimento di Fisica e Astronomia, Universita' di Catania, 95123, Catania, Italy.

Resume : Printed electronics has emerged as a pathway for large scale, flexible, and wearable devices promising to unlock a transformational change in the electronics as we know it, and enabling applications in high demand such as wearable electronics[1], Internet-of-Things[2] and smart textiles[3]. Graphene and related two-dimensional (2D) materials offer an ideal platform of novel materials for high performance printed electronics [4,5]. Electronic inks from 2D materials with different electronic properties have been developed to print the different elements of a device: semiconducting or semimetallic inks in the active layer, insulating inks for dielectrics, and conducting inks for electrodes. However, the complexity of the ink formulations, the three-dimensional assembly of the 2D flakes and the polycrystalline nature of the resulting thin films, have made it difficult to examine charge transport in such devices so far [6], therefore impeding an accurate and controllable design of electronic devices. In this work, we identify and describe the charge transport mechanisms of surfactant- and solvent-free inkjet-printed thin-film devices of representative few-layer graphene (semi-metal), molybdenum disulphide (MoS2, semiconductor) and titanium carbide MXene (Ti3C2, metal) by investigating the temperature, gate and magnetic field dependencies of their electrical conductivity.[7] We find that charge transport in printed few-layer MXene and MoS2 devices is dominated by the intrinsic transport mechanism of the constituent flakes: MXene exhibits a weakly- localized 2D metallic behaviour at any temperature, whereas MoS2 behaves as an insulator with a crossover from 3D-Mott variable-range hopping to nearest-neighbour hopping around 200 K. Charge transport in printed few-layer graphene devices is dominated by the transport mechanism between different flakes, which exhibit 3D-Mott variable range hopping conduction at any temperature.[7] Our results establish the fundamental mechanisms responsible for charge transport in inkjet-printed devices made of 2D material, enabling the controlled design and engineering of future printed electronics based on 2D materials, and paving the way to new types of flexible electronic devices. [1] Torrisi, F. & Carey, T. ?Graphene, related twodimensional crystals and hybrid systems for printed and wearable electronics? Nano Today 23, 73 (2018). [2] C. Scholten et al. ?Advanced Technologies for Industry ? Product Watch: Flexible and printed electronics?, doi: 10.2826/29513 (2021). [3] Carey, T. et al. ?Fully inkjet-printed two-dimensional material field-effect heterojunctions for wearable and textile Electronics? Nat. Commun. 8, 1202 (2017). [4] Torrisi, F. et al. "Inkjet-printed graphene electronics" ACS Nano 6, 2992{3006 (2012). [5] F. Torrisi & T. Carey ?Printing 2D Materials? in ?Flexible Carbon-based Electronics? Editors P. Samori and V. Palermo, Ed.: Wiley-VCH, Weinheim, Germany, 2018. ISBN: 978-3-527-34191-7. [6] D. Akinwande ?Two-dimensional materials: printing functional atomic layers? Nat. Nanotechnol. 12, 287 (2017). [7] E. Piatti, A. Arbab et al. ?Charge transport mechanisms in inkjet-printed thin-film transistors based on two-dimensional materials? Nature Electronics 4, 893 ? 905 (2021).

Authors : E. Abidi, J. A. Delgado-Notario, V. Clericò, J. Salvador-Sanchez, J. E. Velazquez-Perez, J. Calvo-Gallego, E. Diez, T. Taniguchi, K. Watanabe, W. Knap, T. Otsuji,Y. M. Meziani
Affiliations : USAL-NanoLab University of Salamanca (Spain); CENTERA Laboratories, Institute of High Pressure Physics, Polish Academy of Sciences (Poland); USAL-NanoLab University of Salamanca (Spain); USAL-NanoLab University of Salamanca (Spain); USAL-NanoLab University of Salamanca (Spain); USAL-NanoLab University of Salamanca (Spain); USAL-NanoLab University of Salamanca (Spain); National Institute of Material Sciences (Japan); National Institute of Material Sciences (Japan); CENTERA Laboratories, Institute of High Pressure Physics, Polish Academy of Sciences (Poland); Research Institute of Electrical Communication, Tohoku University (Japan); USAL-NanoLab University of Salamanca (Spain);

Resume : The Terahertz (THz) region is the portion of the electromagnetic (EM) spectrum between 0.1 and 10 THz. Across the past decades, motivated by the strikingly vast range of possible applications of THz radiation, many new terahertz techniques have been investigated and demonstrated [1]. In particular, the development of new THz direct detectors [2] is of paramount importance for the development of future communication systems [3]. Graphene-based Fied-Effect Transistors (GFETs) are attractive for the development of highly sensitive THz detectors. Graphene encapsulated between two sheets of h-BN allows the fabrication of GFETs with excellent values of carrier mobility in the transistor channel enabling the use of GFETs as THz detectors [4]. In the present work we present a study both experimental and theoretical of the impact of the use of an antenna on the THz response of a GFET. A GFET based on a vertical dual heterojunction h-BN/graphene/h-BN was fabricated as described in [4]. Graphene and h-BN sheets were obtained by mechanical exfoliation. The graphene sheet was encapsulated between two layers of h-BN and deposited on a SiO2/Si substrate by using the hotpickup technique [4]. The top gate of the transistor was a metallic asymmetric double-grating dual gate (ADGG) that was connected to a broadband bowtie antenna (with a radius of 500 µm and 90º) monolithically implemented on the transistor epilayer structure. The Silicon doped substrate was used as the back gate. The GFET was characterized as a THz detector at low temperature (4K) under radiation at 150, 300 GHz and 600 GHz. The photoresponse signal obtained at 300 GHz showed the higher intensity with a maximum value of 6 mV for a negative value of the backgate voltage close to -7V. This is attributted to a better coupling of the incoming THz at this frequency that is related to both ADGG layout of the gate electrode and the action of the antenna in agreement with EM simulations. A better coupling of the incident radiation with the channel at this frequency could be the reason for the measured signal. Additionally, it was also experimentally observed that when varying the back gate voltage while the top gates are grounded a modulation of the photoresponse arises that was attributed to the formation of regions of carriers of opposite sign along the channel. This creates the conditions in which the plasmonic ratched effect, that is responsible of the rectification of the terahertz radiation, can take place [5, 6]. This opens the way for the development of a new novel devices based on 2d materials for terahertz technology. References: 1. S. Das, et al. Edits. Advances in Terahertz Technology and its Applications, Springer, (2021). 2. R. A. Lewis J. Phys. D: Appl. Phys. 52, 433001 (2019) 3. J.Xie et al. Nanomaterials; 11(7) 1646 (2021) 4. J. A. Delgado Notario et al., APL Photonics 5, 66102 (2020). 5. D. V. Fateev, et al. Appl. Phys. Lett., 110, 061106 (2017). 6. J. A. Delgado et al., Nanophotonics (2022).

Authors : Khomyakov, P. A. (1), Wellendorff, J. (1), Palsgaard, M. (1), Gunst, T. (1), Miyagi, H. (1), Verstichel, B. (1), Arcisauskaite, V. (1), Martinez, U.* (1), Blom, A. (1) & Smidstrup, S. (1).
Affiliations : (1) Synopsys QuantumATK, Fruebjergvej 3, 2100 Copenhagen, Denmark * lead presenter

Resume : As the future brings continued down-scaling of semiconductor device technology, computational screening for alternative materials with improved electronic properties, and investigating the impact of defects, dopants and material thicknesses with atomistic simulations, have become a crucial step in developing next-generation advanced logic, memory, power electronics, and quantum computing. In this talk, we will demonstrate an efficient method for high-accuracy atomistic ab initio simulations for semiconductor device technology development, such as high-k metal gate stack (HKMG) engineering and investigation of 2D material-based FET performance [1]. The method combines the HSE06 hybrid density functional [2,3] with linear combination of atomic orbitals (LCAO) basis sets, as implemented in the QuantumATK atomic-scale modeling platform [4,5] developed by Synopsys. The HSE06-LCAO methodology can be used as part of the recently developed Design-Technology Co-Optimization (DTCO) multiscale atomistic-TCAD [6] workflow by Synopsys for simulating 2D material-based FET performance. This DTCO workflow enables a comprehensive investigation of the impact of various 2D materials and a number of layers, source/drain materials and orientations, doping concentrations, device architecture and dimensions, and other parameters on the full device electrical characteristics. We will show that the HSE06-LCAO method overcomes limitations of local and semilocal (GGA) density functionals and predict accurate band energies, defect trap levels, band offsets, band diagrams and effective work functions for semiconductor materials, interfaces and stacks comprised of several thousands of atoms. Importantly, such large-scale simulations are performed using relatively modest hardware, for example, a band diagram simulation across the 2992 atom HKMG Si|SiO2|HfO2|TiN stack taking only 45 hours on 40 cores. This can be achieved by using LCAO basis sets as they enable orders of magnitude faster simulations than standard HSE06 Plane-Waves (PW) implementations. HSE06-PW has thus so far been practical only for systems with a relatively small number of atoms, limiting the applicability to a small subset of technologically relevant problems. Finally, we will present how HSE06-LCAO is combined with the nonequilibrium Green’s-function method (NEGF) method for studying electron transport, i.e., IV characteristics, of the 2D material (black phosphorous) based FET. References 1) P. Khomyakov, J. Wellendorff, M. Palsgaard, T. Gunst, H. Miyagi, B. Verstichel, F. Corsetti, V. Arcisauskaite, U. Martinez, A. Blom, and S. Smidstrup, ‘Ab initio LCAO hybrid density-functional method for accurate, large-scale electronic structure simulations of semiconductor materials, interfaces and gate stacks’ SISPAD 2021. 2) J. Heyd, G. E. Scuseria, and M. Ernzerhof, ‘Hybrid functionals based on a screened Coulomb potential’ J. Chem. Phys. 124, 219906 (2006). 3) S. V. Levchenko, X. Ren, J. Wieferink, R. Johanni, P. Rinke, V. Blum, M. Scheffler, ‘Hybrid functionals for large periodic systems in all-electron, numeric atom-centered basis framework’ Comp. Phys. Comm. 192, 60 (2015). 4) S. Smidstrup et al. ‘QuantumATK: An integrated platform of electronic and atomic-scale modelling tools’ J. Phys.: Conden. Matter 32, 015901 (2019). 5) 6)

Authors : Gabriele Boschetto*(1), Stefania Carapezzi(1), Corentin Delacour(1), Madeleine Abernot(1), Thierry Gil(1), Aida Todri-Sanial(1)
Affiliations : (1) LIRMM, University of Montpellier, CNRS, 34095 Montpellier, France *Lead presenter

Resume : Atomically thin two-dimensional (2D) materials have been —and are still currently being— extensively studied due to their desirable mechanical, electronic, and optical properties. These, together with the materials' intrinsic ultra-thin size, have the potential to enable the development of compact devices and innovative, beyond-CMOS, technologies. Here we look at single-layer molybdenum disulphide (MoS2) as the core material in 2D memristors for neuromorphic computing applications [1-3]. 2D memristors based on MoS2 present several advantages with respect to conventional devices based on transition metal oxides: good flexibility, high transparency, and the potential to work when applying low voltages (0.1 - 0.2 V), thus allowing the fabrication of compact and energy-efficient devices. However, there is still much debate regarding the physics of their resistive switch, which is thought to depend on both surface defects and the type of metal-semiconductor junction [4]. Moreover, the metal contact is particularly important when designing such devices, as it can significantly influence the properties of MoS2 at the interface. Indeed, both surface defects, which are intrinsically present in the material following common growing techniques such as CVD, and the nature of the metal contact affect not just the performance but also the working mechanism of 2D memristors. To shed light onto the physics of metal-MoS2 interfaces, we carry out atomistic computer simulations in the framework of density functional theory (DFT). We employ surface calculations based on the Green’s function, in order to construct realistic interfaces and to compute surface properties. To model the metal electrode, we choose Au as it is commonly one of the most popular choices, and it has been successfully used to develop 2D memristors [4]. In this work, we want to bridge the gap between materials’ properties and device physics and to do so, we investigate the impact of both experimentally-observed point defects (i.e., vacancies and substitutions) and extended defects, such as grain boundaries, on the physics and chemistry of Au-MoS2 interfaces. To the best of our knowledge, this is the first attempt to thoroughly model interfaces in the presence of grain boundaries. Ultimately, our study constitutes the first step of a more comprehensive multi-scale modelling approach, in which the aim is to construct a full atomistic-to-device level model that can aid us in elucidating the working mechanism of 2D memristors based on single-layer MoS2. [1] EU H2020 NeurONN Project, [2] A. Todri-Sanial et al., IEEE Trans. Neural Netw. Learn. Syst., 1-14, 2021. [3] A. Todri-Sanial, MRS Fall Meeting and Exhibit, 2021. [4] R. Ge et al., Nano Lett., 18, 434-441, 2017.

Authors : Navaneeth Krishnan K*, Anjusree S, Srikrishna Sagar, Litty Thomas Manamel, Arka Mukherjee and Bikas C. Das
Affiliations : Emerging Nanoelectronic Devices Research Laboratory (eNDR Lab), School of Physics, Indian Institute of Science Education and Research Thiruvananthapuram (IISER TVM), Maruthamala PO, Vithura, Thiruvananthapuram 695551, Kerala, India.

Resume : Self-powered broadband ultrathin photodetector provides excellent commercial value for a wide range of optoelectronic applications, including neuromorphic functions, safety and security, and many more. We used thermal CVD grown in situ MoS2 embedded in solution-processed copper phthalocyanine (CuPc) thin film to show such a photodetector produced cost-effectively and robustly. Surprisingly, a behaviour comparable to the photogating effect has been identified, which occurs when carriers are trapped at defect sites and the dielectric interface of layered materials. Because carriers are trapped in 2H-MoS2 flakes due to type–II staggered band alignment with CuPc, we called this the spontaneous photogating effect. Estimating the EQE between the spectral regions of 0.3 to 1.1 micron with a maximum of 300% is used to detect the broadband spectral response. We achieved a response speed of 50 ms rise and 60 ms fall time with responsivity and detectivity of roughly 0.7 A/W and 10^11 Jones, respectively. On the other hand, this study suggests that spontaneous photogating has no effect on device reaction time. As a result, the technique described here will expand the use of various TMDs combined with diverse organic materials to create more robust ultrathin self-powered broadband photodetectors with higher figures of merit.

Authors : Veronika Zadin, Andreas Kyritsakis, Flyura Djurabekova, Tauno Tiirats, Mihkel Veske
Affiliations : University of Tartu, Estonia; University of Tartu, Estonia; University of Helsinki, Finland; University of Tartu, Estonia; University of Helsinki, Finland.

Resume : FEMOCS [1-2] is a unique software that allows multiscale computer simulations, combining atomistic and electromagnetic field analyses together with heat transport calculations for the development of nanoelectronics, nanomaterials and nanoelectromechanical systems (NEMS). The software has been developed to solve materials technology problems of CERN particle accelerator designs, but also has applications in ITER, space applications and high-tech R&D. The functionality of FEMOCS centers on nanostructure changes of materials in severe conditions by providing of a computational framework that combines Finite Element Analysis (FEA), atomistic simulations such asMolecular Dynamics (MD) and kinetic Monte Carlo (KMC), and Particle In Cell models, to investigate the effect of high electric fields on surfaceinteractions. The challenges to be solved include surface electric field calculation accuracy and sensitivity to atom localization, but also electric field influence to the atomic interactions and investigation of the respective corrections in the computational models. Currently, the FEMOCS code can be executed together with PARCAS or LAMMPS molecular dynamics packages. It is also possible to run simulations in conjunction with the KIMOCS KMC code for extended time scales, opening opportunities for investigating the effects of interface composition and material structure (surface roughness, geometry) to the material’s ability to resist the damage over longer time scales (defect localization, surface diffusion). The main features incorporated into FEMOCS code are the atomistic dynamics calculations of bulk and surfaces using molecular dynamics simulations (currently metals ), finite element calculations of near surface electric fields (using open source DEAL.II library). The field emission currents by incorporating state of the art general thermal field models with combined thermionic and field emission, Nottingham heating effects and surface curvature corrections using the GETELEC code [3]. The atomistic dynamics of surfaces are complemented by the space charge formation and screening effects, surface evaporation and initial stages of plasma formation with a capacity for concurrent PIC simulations. Furthermore, future developments are proceeding towards extending the functionality of the code to the semiconductor materials by not only incorporating material in molecular dynamics sub-model but also by incorporating the respective corrections to the electric field calculations and tunneling behavior of electrons into the electron emission models. 1. Veske, Mihkel, et al. "Dynamic coupling of a finite element solver to large-scale atomistic simulations." Journal of Computational Physics 367 (2018): 279-294. 2. FEMOCS source code - 3. Kyritsakis, Andreas, and Flyura Djurabekova. "A general computational method for electron emission and thermal effects in field emitting nanotips." Computational Materials Science 128 (2017): 15-21.

14:45 Discussion    
Electronic Materials : Sreetosh Goswami, Yogendra Kumar Mishra, Dawid Janas
Authors : Youbin Zheng, Rawan Omar, Rongjun Zhang, Ning Tang, Muhammad Khatib, Qi Xu, Yana Milyutin, Walaa Saliba, Yoav Y Broza, Weiwei Wu, Miaomiao Yuan*, and Hossam Haick*
Affiliations : Department of Chemical Engineering and Russell Berrie Nanotechnology Institute, Technion-Israel Institute of Technology, Haifa 3200003, Israel

Resume : Dysnatremia, a disorder in the concentration of sodium levels, possesses a clinical challenge leading to adverse health complications. Using biosensors for online sodium monitoring can be a promising approach to overcome this condition. In this regard, biosensors based on field-effect transistors (FETs) have promising advantages, including high sensitivity, quick response, and easy fabrication. Most of the currently developed FET designs are used only for sensing sweat and in-vitro blood/interstitial fluids (ISF). Using ISF for online detection of biomarkers and long-term health monitoring with FETs has not yet been fully resolved. Herein we proposed an innovative stretchable skin-conformal fast-response microneedle extended-gate FET (MN-EGFET) biosensor for real-time detection of sodium in the ISF for minimally invasive health monitoring along with high sensitivity, low limit of detection, excellent biocompatibility, and on-body mechanical stability. The device relies on a new architecture of FETs whose sensing part and reference electrode rely on extended gate (EG) made of microneedles (MNs) that penetrate the skin to reach the ISF or measuring the sodium therein. The electrical response of the reported sensors over sodium concentration, repeatability and selectivity have been conducted to characterize their performance. The mechanical stability of the platform has also been evaluated by on-body experiments and the response recorded over MNs inserting and peeling-off cycles. In-vitro and in-vivo biocompatibility experiments of the MNs were validated to prove their function in transnational clinical and on-body applications. This platform can, furthermore, be integrated with wireless-data transmitter and the Internet-of-Things (IoT) cloud for real-time monitoring and long-term analysis, showing great potential for home healthcare and clinical diagnosis. This wearable MN-EGFET platform may provide a new fundamental detection technique through further on-body evaluation.

Authors : Simon Tricard
Affiliations : LPCNO , INSA, CNRS, Université de Toulouse, France

Resume : A main goal of electronics in hybrid materials is to relate device performance to the structure and electronic state of the building components. In particular, nanostructured hybrid materials made by self-assembly of nanoparticles and functional molecules have been proven to be very sensitive to the nature of the molecular components. Among the variety of possibilities that organic, organometallic and coordination chemistries offer to tune the energy levels of these molecular components, spin crossover phenomenon is a perfect candidate for the elaboration of molecular switches. The reorganization of the electronic state population of the molecules associated to the spin crossover can indeed lead to a significant change in conductivity of the hybrid materials. Here, we show that the association of ultra-small 1.2 nm platinum nanoparticles with FeII triazole-based spin crossover coordination polymers leads to self-assemblies, extremely well organized at the sub-5 nm scale. The quasi-perfect alignment of nanoparticles observed by transmission electron microscopy, in addition to specific signature in infrared spectroscopy, demonstrates the coordination of the long-chain molecules with the nanoparticles. Spin crossover is confirmed in such assemblies by X-ray absorption spectroscopic measurements and shows unambiguous characteristics in both magnetic and charge transport measurements. The conductive properties of the materials was governed by Coulomb blockade in the ultra-small nanoparticles, and was shown to depend on the polarizability switch of the molecular components. Spin crossover coordination polymers are therefore ideal candidates for the elaboration of switchable hybrid materials self-assembled with metal nanoparticles, where molecular effects govern the electric responses.

Authors : Sergio Gonzalez-Munoz, Khushboo Agarwal, Eli Castanon, Zakhar Kudrynskyi, Zakhar D. Kovalyuk, Jean Spièce, Olga Kazakova, Amalia Patane, Oleg Kolosov
Affiliations : Sergio Gonzalez-Munoz, Lancaster University; Khushboo Agarwal, Lancaster University; Eli Castanon, National Physical Laboratory; Zakhar Kudrynskyi, University of Nottingham; Zakhar D. Kovalyuk, Institute for Problems of Materials Science (NAS of Ukraine); Jean Spièce, Université catholique de Louvain; Olga Kazakova, National Physical Laboratory; Amalia Patane, University of Nottingham; Oleg Kolosov, Lancaster University

Resume : Nanoscale thermal transport is a key factor limiting the clock speed of computer processors and defining the performance of thermoelectric (TE) materials. While in the former the increase of heat dissipation is essential, in the latter, low thermal conductivity provides a major boost to the TE figure of merit (FoM). The versatility of van der Waals (vdW) materials and their heterostructures provide an extremely useful toolbox for addressing the control of thermal transport in diverse applications. The challenge nevertheless lies in the difficulty of measuring and quantifying the thermal transport within atomically thin and highly anisotropic vdW materials and between these materials and substrates. Here we report a powerful approach of cross-sectional scanning thermal microscopy (xSThM) for studying anisotropic heat transport in nanoscale layered vdW materials. We use beam exit cross-sectional polishing (BEXP) of vdW nanoflakes shaping these into ultra-thin low angle wedges with atomic-scale surface flatness, followed by the xSThM in high vacuum (HV) conditions. By mapping continuously varying sample thickness of the wedge, we eliminate artefacts of through-the-air heat transport and suppress a generally unknown SThM tip-surface interfacial thermal resistance. By comparing experimental results with the finite element analysis (FEA) simulation and analytical models, we can directly evaluate the anisotropy between the in-plane and cross-plane thermal conductance of the vdW materials, the local thermal resistance at the vdW material–substrate interface and the SThM tip-material thermal resistance. We apply this approach to quantify the thermal conductivity of gamma indium selenide (γ-InSe), which has high potential in TE applications due to its advantageous electrical and thermal properties. xSThM allowed us to independently confirm the heat transport anisotropy and anomalous low thermal conductivity values of k‖ = 2.164 W/mK and k⊥ = 0.8897 W/mK for γ-InSe on Si, also extracting the interfacial thermal resistance between γ-InSe and Si (rint = 9.6x10-11 Km2W-1). Our results support the potential of γ-InSe as a high TE efficiency material, where the low thermal conductivity values can be combined with a high power factor, ultimately enhancing the FoM.

Authors : L. G. Mesa, C. J. Páez
Affiliations : Universidad Industrial de Santander

Resume : We investigate here how the current flows over a single crystal of SmB6[1] in the presence of an external electric field perpendicularly applied. For this purpose: (i) we calculated the band structure in order to construct the minimal tight-binding type model for the Sm 4f bands of SmB6 based on localized Wannier functions, and (ii) we applied the recursive Green's function method[2] to the computation of electronic transport properties of SmB6 in the linear response regime. Our results show that current flows over the surface, the region of the system with higher charge density, as the bulk conductivity freezes out. This system's charge density polarization opens an energy gap, which the electric field can manipulate. [1] Bulk and surface properties of SmB6, Priscila F. S. Rosa, Zachary Fisk, arXiv:2007.09137, 2020. [2] The recursive Green’s function method for graphene, Caio H. Lewenkopf and Eduardo R. Mucciolo , J Comput Electron 12, 203–231 (2013)

Authors : E. Bonaventura (1-2), D. Dhungana (1), S. Macis (3), C. Grazianetti (1), C. Martella (1), E. Bonera (2), S. Lupi (3), A. Molle (1).
Affiliations : 1 - CNR-IMM Unit of Agrate Brianza, via C. Olivetti 2, Agrate Brianza, Italy 2 - Department of Material Science, University of Milano-Bicocca, Via Cozzi 53, Milan, Italy 3 - Department of Physics, Sapienza University, Piazzale Aldo Moro 5, 00185 Rome, Italy

Resume : The dimensional reduction brought by the advent of two-dimensional (2D) materials opened new routes for nanoelectronics and photonics applications [1]. In this framework, the Xenes (artificial graphene-like monoelemental lattices) represented a new forefront because of their peculiar geometric and electronic structure [2]. For years silicene has been considered a good candidate for new applications due to its predicted electronic and optical properties, and intrinsic allotropic affinity for currently used silicon-based technology. Unfortunately, the instability in air and strong hybridization effects with the native substrates limited its use to date. Interface states built up by silicon and the supporting substrate have great impact on the physical properties of the epitaxial silicene and, in the case of silicene on silver, no evidence was found of Si adlayers maintaining freestanding silicene characters [3,4]. In this framework, the Xene-based heterostructure concept takes on a certain relevance for the abovementioned issues. It has recently been shown that silicene-on-silver and stanene on-silver can operate as templates for the epitaxy of the reciprocal Xene single-layer, giving rise to different types of heterostructure [5]. Here, we report on the optical properties of these new Xenes-based configurations made accessible by spectroscopic measurements in the MIR-UV spectral range (from 0.12 to 5.8 eV), in reflection geometry. Our analysis highlights the role of the interlayer in modifying the coupling of the on top Xene and the native substrate, resulting in a different reflectivity spectrum when silicene and stanene are combined. More in detail, we demonstrate that the buffer layer has a dramatic impact on the bandstructure hybridization between the Xene and the substrate, thus resulting in a modification of the optical response of the whole system. Finally, the decoupling effect is studied in terms of the photo-thermal Raman response, revealing stark differences in the heat transport properties of single layer epitaxial Xenes and heterostructures. To conclude, we point out that deepen the knowledge about the building blocks of heterostructures and explore different combinations of them is indeed essential for extending the range of their functionality and applications. References: [1] Grazianetti, C., Martella, The Rise of the Xenes: From the Synthesis to the Integration Processes for Electronics and Photonics. Materials 14, 4170 (2021) [2] Molle, A. et al. Buckled two-dimensional Xene sheets. NATURE MATER VOL PAG(2017) [3] Cinquanta, E. et al. Optical response and ultrafast carrier dynamics of the silicene-silver interface. Phys. Rev. B 92, 165427 (2015) [4] Hogan, C. et al. Optical properties of silicene, Si/Ag(111), and Si/Ag(110). Phys. Rev. B 97, 195407 (2018) [5] Dhungana, D. S. et al. Two-Dimensional Silicene–Stanene Heterostructures by Epitaxy. Adv. Funct. Mater. 31, (2021)

Authors : Dmitriev D.V., Kolosovsky D.A., Toropov A.I. & Zhuravlev K.S.
Affiliations : Rzhanov Institute of Semiconductor Physics, Novosibirsk 630090, Russian Federation

Resume : InP(001) substrates are actively used for growing heterostructures of high-power photodiodes for microwave photonics systems [1]. Pre-epitaxial thermal cleaning of InP substrates in an arsenic flux makes it possible to obtain a sharp layer/substrate heterointerface and avoid uncontrolled incorporation of phosphorus into InAlAs/InGaAs layers lattice-matched with InP(001) substrate. When arsenic interacts with the oxidized InP surface, a solid solution InP1-?Asx is formed, the composition of which depends on the annealing temperature and the arsenic flux [2]. However, the mechanisms of the oxide removal and surface transformation are not fully understood. It is obvious that understanding these processes is important for technologies for the heterostructures growth on InP. In this work, the mechanisms of oxide removal from the surface of an epi-ready InP(001) substrate in arsenic flux are studied in situ by the method of reflection high-energy electron diffraction (RHEED). The studies were carried out in a Compact-21T molecular beam epitaxy system from Riber. We observed a slow increase in the (00) reflex intensity at T>250 °C without an arsenic flux, which indicates thermal removal of the oxide. At the moment of switching on the arsenic flux FAs=6×10-6 Torr at T=300 °C, there are no changes in the dependence of the (00) reflex intensity, i.e. the contribution of interaction with As to oxide thinning is insignificant. At T~350 °C, the nature of the oxide removal process changes sharply, which is associated with the activation of the chemical reaction of the interaction of arsenic with oxide. With a large flux FAs=2×10-5 Torr, a sharp thinning of the oxide layer occurs. This is due to the increased contribution of the chemical reactions of As and oxide, which is proportional to the concentration of As. However, as a result of these reactions, the oxide is not completely removed, and upon further heating, a slow thermal thinning of the oxide occurs. At a temperature of T~410 °C, the maximum intensity of the (00) reflex is reached, which indicates the complete removal of the oxide layer, which no longer scatters the electron beam. The subsequent decrease (00) reflex intensity is associated with an increase in the surface roughness due to desorption of phosphorus and segregation of indium, but with a higher flux of arsenic it occurs more slowly, since the flux increase decreases the desorption of V-group elements from the surface. Thus, the oxide layer is likely to consist of two types of oxides, one of which actively interacts with As, and the other decomposes predominantly thermally. References [1] K. S. Zhuravlev, et al., J. Semicond. 43 (2022) 012302. [2] D.V. Dmitriev, et al. Surface Science 710 (2021) 121861.

17:30 Discussion    
Start atSubject View AllNum.
Carbon Nanomaterials : Ayan Chaudhuri, Yogendra Kumar Mishra, Sugato Hajra
Authors : Dawid Janas
Affiliations : Silesian University of Technology, Department of Organic Chemistry, Bioorganic Chemistry and Biotechnology, Krzywoustego 4, 44-100 Gliwice

Resume : Carbon nanostructures such as carbon nanotubes or graphene are some of the most fascinating materials of the XXI century. Ever since it was discovered that their optical, electrical, mechanical, and thermal properties outperform the characteristics of many traditional materials, the research community has focused on finding ways to deploy them in real life. A myriad of possible applications has been envisioned, but a full realization of these aspirations is still a long way off after three decades of progress in this area. This presentation will present the main challenges that need to be tackled to change this state of affairs, solving of which would greatly increase the technology readiness level of prototypes based on nanocarbon. The main issues are the lack of an appropriate degree of structure control, which governs the properties, as well as the absence of straightforward and scalable methods to make macroscopic networks from individual carbon nanotubes or graphene flakes. The contribution will show how these difficulties can be handled using carbon nanotubes as a model nanocarbon material. The talk will display our advances on the fronts of purification of single-walled carbon nanotubes and their assembly into free-standing networks. Furthermore, the presentation will cover our recent progress in tuning the material's properties by simple chemical or physical treatments. Finally, the broad application opportunities for such nanostructures will be highlighted.

Authors : Qinrong He, Han Zhang, Joe Briscoe*
Affiliations : School of Engineering and Material Science and Materials Research Institute, Queen Mary University of London, London, E1 4NS

Resume : ?Internet of Things? (IoT) has attracted intensive interest for the field of wireless, portable and monitoring electronics fields. In thise regard, a wearable nanogenerator hold great potential because it can harvest the energy from body movement and surrounding environment to provide sustainable power supply for these electronic devices. Zinc oxide (ZnO) nanostructures have been extensively investigated for harvesting mechanical power owing to its piezoelectric properties combined with low cost, non-toxicity and easy synthesis. [1-3] Carbon fibre has attracted lots of attention due to its unique properties of lightweight, thermally agood conductivity and chemically stability, which is widely applied in the automotive, aerospace and other industrial fields. Herein, a PEDOT:PSS/CuSCN/ZnO energy harvester is successfully fabricated on conductive carbon fibres utilising, combining the advantages of ZnO piezoelectricity and flexibility and electrical conductivity of carbon fibres. PEDOT:PSS/CuSCN structure was fabricated on ZnO nanorods to reduce the rate of screening to achieve higher performance output. The device generates increasing output voltage from 1.4 V to 7.6 V as the impacting acceleration increases from at 0.1 m/s2 to 0.4 m/s2. The device also shows high stability and durability under 26000 cycles test byof impacting testing. In addition, the device is able to harvest energy from biomechanical forces such as impacting, flicking and gentle finger tapping and bending. The output voltage from the device can activate an LCD screen display by finger tapping. In addition, based on carbon fibre itsis used to form the composite, carbon fibre-reinforced plastic (CFRP), A CFRP-based self-powered sensor was also fabricated, of which exhibits the voltage/current output is proportional to the impacting force, therefore it can act as a self-powered impacting sensor with good stability during the 26000 cycles test. The results provides an efficient method to develop energy harvester on carbon fibres, which hold great potential for the future designing of flexible self-powered devices and wearable electronics.

Authors : Rossella Zaffino*, Raphael Pfattner*, Daniel Riba*, Teresa Cardona*, Daniel Herrera*, Arántzantzu González-Campo*, Herre S. J. van der Zant**, Núria-Aliaga Alcalde*¥
Affiliations : *Institut de Ciència de Materials de Barcelona ICMAB-CSIC, Carrer dels Til·lers Campus Universitat Autonoma de Barcelona, Bellaterra, Spain; **Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, Delft 2628 CJ, The Netherlands; *¥ICREA – Institució Catalana de Recerca i Estudis Avançats, Passeig Lluis Companys 23, 08010 Barcelona, Spain;

Resume : Reliable molecular electronic and spintronic devices require precise control of the atomic coordinates of both, the molecules and the atoms of the electrodes. The lack of specific chemistry for the efficient bridging of the molecules between the electrodes from one side, and the extremely difficult fabrication of electrodes at the molecular scale from the other, are the principal challenges in the field [1]. In this work, we present the fabrication and characterization of graphene nanogap electrodes embedded in a three-terminal device. We obtain the graphene nanodevices by applying standard and advanced lithography combined to feed-back controlled electro-burning [2,3]. In a second step, the aim is the creation of robust π-π anchoring of ad-hoc synthesized curcuminoid molecules. The viability of the fabricated devices for nanoelectronic applications is corroborated by using different characterization techniques. This work was supported by the project PID2019-108794GB-I00 (AEI/FEDER, UE) and the European Research Council Consolidator Grant Tmol4TRANS (ERC 724981). AGC and RP acknowledge the Ramon y Cajal fellowships program RyC 2017-229210 and RyC 2019-028474I. [1] Amar H. Flood, J. Fraser Stoddart, David W. Steuerman, James R. Heath, Science, 5704 (2004) 2055-2056. [2] Enrique Burzurì, Joshua O. Island, Raúl Díaz-Torres, Alexandra Fursina, Arántzantzu González-Campo, Olivier Roubeau, Simon J. Teat, Núria Aliaga-Alcalde, Eliseo Ruiz and Herre S.J. van der Zant, ACS Nano, 10 (2016) 2521-2527. [3] Cornelia Nef, László Pósa, Peter Makk, Wnagyang Fu, András Halbritter, Christian Schönenberger and Michel Calame, Nanoscale, 6 (2014) 7249-7255.

Authors : Pepper Yang (1), Martin Holicky (1), Benji Fenech Salerno(1), David M. E. Freeman (1), Anthony E. G. Cass (1), Felice Torrisi (1)
Affiliations : Imperial College London, United Kingdom

Resume : Antimicrobial resistance is a major global health issue. Optimised and personalised dosing of antibiotics is one of the routes to target the issue.1,2 Personalized dosing is achievable via real time drug monitoring.3 Current state of the art biosensors can provide continuous monitoring of a prototypical antibiotic, penicillin, in the dermal interstitial fluid.3 However, this biosensor requires expensive materials such as iridium oxide as its pH sensitive layer.3 This work presents an alternative low-cost graphene-based sensing platform for real time measurement of penicillin. The graphene sensing platform is based on selective enzymatic conversion of the antibiotic and the measurement of the resulting pH change. A range of immobilisation methods is investigated to better encapsulate the enzyme. The optimal composition of the hydrogel membranes surrounding the graphene sensor is investigated that enhance the selectivity as well as reducing interference from other molecules. The biosensing device achieved a resolution of 0.05 pH units within the relevant range (pH 7 – 8) and analyte detection sensitivity which is comparable to the current state of the art.3 The results from this graphene-based sensing platform will enable production of low-cost, scalable and versatile, high-performance real time antibiotic sensors. 1 D. G. J. Larsson and C. F. Flach, Nature Reviews Microbiology, 2021. 2 T. M. Rawson, S. A. N. Gowers, D. M. E. Freeman, R. C. Wilson, S. Sharma, M. Gilchrist, A. MacGowan, A. Lovering, M. Bayliss, M. Kyriakides, P. Georgiou, A. E. G. Cass, D. O’Hare and A. H. Holmes, The Lancet Digital Health, 2019, 1, e335–e343. 3 S. A. N. Gowers, D. M. E. Freeman, T. M. Rawson, M. L. Rogers, R. C. Wilson, A. H. Holmes, A. E. Cass and D. O’Hare, ACS Sensors, 2019, 4, 1072–1080.

Authors : Teng-Chin Hsu1 , Bi-Xian Wu1 , Rong-Teng Lin1, Chia-Jen Chien1, Chien-Yu Yeh1, Tzu-Hsuan Chang1*
Affiliations : 1 Graduate Institute of Electronics Engineering, National Taiwan University, Taiwan ; 2 Department of Materials Science and Engineering, National Taiwan University, Taiwan; *email:

Resume : Graphene nanoribbon with width scaling down to nanometers can have bandgap opened and its electrical properties is dominated by the localized electronic states of edge atoms. However, the electron mobility of graphene nanoribbons decreases rapidly with the reduction of the edge width due to the change in the energy band and limited by the increased acoustic and optical phonon scattering. In this study, we explore the graphene nanoribbons with periodic edge structures that can balance the bandgap opening and the disrupt the phonon interaction that limits the electron drifting in the graphene nanoribbons. In this way, graphene nanoribbon with bandgap opened while still maintaining high mobility can be the appealing candidate for the next generation semiconductors. In this study, we focus on the Coved graphene nanoribbons (CGNRs) with edges containing periodic zigzag and armchair nanoribbons. Based on the density function theory(DFT), the electrons and phonons all-energy band of the CGNRs is calculated and considered in mobility calculation. The edge structure leads a big influence of the electron-phonon coupling that effectively limit the influence of phonons on electron mobility. Compared with the same wide zigzag graphene nanoribbons (ZGNRs), the electron mobility of the CGNRs is about 8.6E4 cm2/Vs, which can be an order of magnitude higher. To extend the structure of CGNRs to be compatible the scale of current fabrication facility, we designed the edges of CGNRs have an isosceles triangle with an apex angle of 120 degrees to generate a 120-degree coved shape with edge alignment. We find that the mechanism of bandgap opening of the CGNRs will be the same as the Armchair GNRs: the band gap will be zero in a 3N 2 relationship with the number of atoms. However, as the isosceles triangle of the coved shape gradually increases, the band gap of CGNRs will gradually converge and can expel the zero band gap cases, which is essential for the large-scale circuits level engineering. In this way, moderate fault tolerance of edge condition during the fabrication of the GNRs can be allowed. In our design, CGNRs will have a band gap more than 0.1±0.05eV in a maximum width more than 20nm and a minimum width less than 8nm and a band gap of more than 0.2±0.1eV in a minimum width less than 4nm. The further device simulation is based on quantum transport by means of the Nonequilibrium Green’s Functions (NEGF) and considered about phonon dispersion. The CGNRs structure has a band gap and has better mobility about 1.0E4 cm2/Vs compared to ZGNRs of the same average width. This method can be applied to other semiconductor materials to get IV characteristic and provides important direction for experiments. To integrate our fabrication with the current semiconductor industry, our experimental process utilizes the chemical vapor deposition (CVD) equipment to manufacture a single layer and single crystal graphene film on a germanium substrate. With E-beam lithography (EBL) to pattern the graphene in coved shape, the CGNRs can be defined into sub 10nm dimensions. The edge defect of patterned nanoribbons during the processing can be later repaired through "equilibrium growth conditions", that is tuned with deposition rate of graphene grains close to zero to self-repair the damaged edge during fabrication process. This method reduce defect and enhance edge quality of the CGNRs, that makes mobility increasing while maintaining band gap opened. That the GNRs can become a material that can be used in the semiconductor industry.

Authors : Anteneh Fufa Baye,Hern Kim* Lead presenter : Anteneh Fufa Baye , Email: Corresponding author*: Hern Kim , Email:
Affiliations : Environmental Waste Recycle Institute, Department of Energy Science and Technology, Myongji University, Yongin, Gyeonggi-do 17058, Republic of Korea

Resume : Quantification of hydrogen peroxide (H2O2) in the food industry is a vital step in censoring food safety. The colorimetric detection method has prevailed over other techniques in terms of simplicity to monitor by the naked eye. To date, natural enzymes were used to catalytically convert the substrate into a visually detectable product. Regardless of their high selectivity and specificity, they undergo denaturation resulting in unstable detection. Therefore, nanomaterials with enzyme-like activities are better alternatives for replacing natural enzymes. In this study, Fe species/ZnO@g-carbon composite was prepared with intrinsic peroxidase-like activity via carbothermal reduction using ZnFe-double-layer hydroxide and glucose-derived carbon as precursors. The physicochemical properties of Fe species/ZnO@g-carbon were studied by XRD, XPS, BET, FE-SEM, and TGA analysis. It exhibits excellent peroxidase activity towards the oxidation of 3, 3?, 5, 5?-tetramethylbenzidine (TMB) in the presence of H2O2. The enhanced peroxidase activity is attributed to multiple oxidation states of Fe, quick electron transport ability of porous graphitic carbon. Our results demonstrate that Fe species/ZnO@carbon is a promising candidate for enzyme mimic sensing of H2O2 in food samples.

09:45 Discussion    
Hybrid Materials : Yogendra Kumar Mishra, Sugato Hajra, Jost Adam
Authors : Ogbeide, O. (1), Bae, G. (1), Yu, W. (1, 2), Morrin, E. (1), Song, Y. (1), Song, W. (3), Li, Y. (2), Su, B.-L. (2), An, K.-S. (3), Hasan, T. (1)
Affiliations : (1) Cambridge Graphene Centre, University of Cambridge, United Kingdom; (2) State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, China; (3) Thin Film Materials Research Center, Korea Research Institute of Chemical Technology (KRICT), Republic of Korea

Resume : In recent years, a range of 0D-2D hybrids with single metal oxides and 2D materials have been exploited for gas sensing due to their synergetic advantages; low-dimensional nature of the 2D materials with interesting electronic properties and highly catalytic reactivity at the oxide interfaces. However, their performance sensitivity, measurement repeatability and certainty (i.e., selectivity) in a mixed gas environment at low power remains inadequate for practical applications. Herein, we address these challenges with a multi-pronged approach consisting of hydrothermal-assisted hybridization of rGO with CuCoOx binary metal oxide to form our sensing material, formulation of a functional rGO/CuCoOx inkjet printable ink for commercially scalable device fabrication, and the novel incorporation of computational techniques and machine-learning algorithms for measurement certainty. Our fabricated chemiresistive devices are fully printed on porous polyethylene terephthalate (PET), the interdigitated electrodes (IDEs) are printed from a commercial silver ink and our sensing material is printed on top of the desired area. The device performance is investigated in both single and mixed gas environments, achieving outstanding sensitivity with 50 ppb of limit-of-detection of NO2 at room temperature. Moreover, we show superior measurement repeatability, stability and excellent signal-to-noise (SNR) of 212.2 at low ppb concentrations. In efforts to achieve greater certainty in our gas measurements we apply principal component analysis (PCA) in tandem with machine learning techniques. Our 10-extracted parameters from transient gas response curves from a single sensor are adequate for utilizing a machine-intelligent classifier, resulting in excellent accuracy for identifying specific gases and predicting their concentration in a mixed atmosphere. A clear decision boundary for 5-different gas species with 98.1% accuracy. Furthermore, our approach of projecting a regression surface onto the classifier plane allows the sensor to predict unseen NO2 and humidity concentrations reliably. We firmly believe that our work represents a breakthrough in the field of 0D-2D material systems for low-temperature machine-intelligent gas recognition platforms in a mixed environment irrespective of ambient humidity.

Authors : Tae-hoon Kim (1), Jong-In Hong*(1)
Affiliations : (1) Department of Chemistry, Seoul National University, Seoul 08826, Republic of Korea

Resume : Recently, single-walled carbon nanotube (SWNT)/organic semiconductors (OSCs) hybrids have received great attention as thermoelectric (TE) materials due to their characteristics such as flexibility, low toxicity, abundance, light-weight, and robustness. Numerous SWNT/OSCs TE hybrids have been explored to ameliorate electrical properties over the past decade, however, the clear explanation on how the energy level of OSCs affects the TE performance of their hybrids is still elusive. In this presentation, we present a correlation between the electronic levels of OSCs and the TE performance of their hybrids with carbon nanotube by simultaneously modulating the HOMO levels and bandgap of organic small molecules (OSMs). We achieved considerably high ZT for carbon nanotube-based hybrid thermoelectrics via synergistically improved Seebeck coefficient without using conventional dopants. To mechanistically comprehend TE properties of carbon nanotube-based composites at a molecular level, we utilized organic small molecule (OSM) as a hybridizing component as the energy level of OSMs can be easily modulated. The HOMO levels and bandgap of three stilbene-based OSMs (CzS, CzCNS, CzdCNS) were controlled by differentiating the number of cyano (CN) groups on the trans-stilbene backbone. The CzS retaining a larger bandgap (3.03 eV) and having the smallest energy discrepancy to the valence band of SWNT (0.04 eV) among three OSMs enabled its hybrid with SWNT (SWNT/CzS) to have largely enhanced Seebeck coefficient of 108.8 μV K-1 and ZT of 0.058 at room temperature, which are 1.5 and 2.9 times higher than those of SWNT/CzdCNS with a large energy barrier (0.70 eV) and a relatively smaller bandgap of CzdCNS (2.31 eV). Without any additional chemical dopants, we achieved the best ZT value at room temperature among the SWNT and small molecule-based TE materials to date. Measurements of the Seebeck coefficients in OSMs film states provide a rationale that the enhanced TE performance of SWNT/CzS could be attributed to the synergism between the widened bandgap of CzS and the promoted energy filtering in SWNT/CzS. Temperature-dependent resistivity of SWNT/CzS with small barrier energy and relatively homogeneous morphology predominantly follows the variable range hopping conduction model, validating much more efficient carrier transport between SWNT and CzS than between SWNT and CzdCNS. Our transport model is the first systematic elucidation for the conduction mechanism between SWNT and OSMs. We strongly believe that our fundamental, but simple method with energy level control will be applied to other diverse hybrid TE systems as well as carbon nanotube-based hybrid.

Authors : 1. A.V. Kukhta, A.G. Paddubskaya, T.A. Kulahava, S.A. Maksimenko 2. T.A. Pavich 3. P.Ciambelli, P. Lamberti
Affiliations : 1. Institute for Nuclear Problems, Belarusian State University, Babruiskaya Str. 11, 220006 Minsk, Belarus 2. B.I.Stepanov Institute of Physics, National Academy of Sciences of Belarus, Minsk, Belarus 3. University of Salerno, Fisciano, Italy

Resume : We proposed a highly luminescent and electrically conducting polymer composite material based on polylactide acid (PLA) polymer filled with supramolecular europium complex supported by2D nanoplatelets(graphene oxide or MoS2) as a structure-forming site. Conductivity of the composite film is increased several orders of magnitude as compared to the pure polymer. The simple and reliable proposed procedure is prone to be easily scaled up and open the route for the commercialization of this nanomaterial.The proposed material is suitable for 3D printing technology and wide applications in optoelectronics.

Authors : Mariia Stepanova1, Reza Abolhassani2, Jacek Fiutowski2, Horst-Gunter Rubahn2, Anna Orlova1, Yogendra Kumar Mishra2
Affiliations : 1 ITMO University, Russia 2 Mads Clausen Institute, University of Southern Denmark, Alsion 2, DK-6400, Sønderborg, Denmark

Resume : Water pollution is among one of the major problems, whole world is facing today and building nanomaterials based systems for water purification and recycling could offer potential solutions in this direction. Zinc oxide tetrapod like nanomaterials (1) from metal oxide semiconductor family, are being tested as photocatalysts for the decomposition of various organic dyes. They are excellent candidates for photocatalysis due to their novel properties, affordable production, etc. however, in pure form, the zinc oxide tetrapods exhibit relatively lower photocatalytic activity. Their photocatalytic response can be further enhanced by hybridizing them with certain external nanostructures (2) and, especially using carbon dots due to their attractive properties, like easy synthesis, high biocompatibility, and high photostability, etc. In this work, the surface of zinc oxide tetrapods from flame process (1) was modified with carbon dots to fabricate the hybrid composites and their photocatalytic performance is investigated in detail. Two types of composites are synthesized, i.e., carbon dot-decorated tetrapods and core/shell composites obtained by magnetic stirring and the solvothermal methods. The composites were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), and UV-visible absorption and photoluminescence spectroscopy. The photocatalysis activitiy of hybrid composite was measured against three different types of dyes (Methyl Blue, Methyl Orange, and Methyl Red) and under two irradiation wavelengths (405 nm and 450 nm). The composites demonstrated high photocatalytic efficiency with the possibility of reuseing them upto three cycles. The detailed photocatalytic investigations from the fabricated composites will be presented and discussed here. References: 1. 2.

Authors : Tahereh Nematiaram Alessandro Troisi
Affiliations : University of Liverpool

Resume : Transparent conducting materials are an essential component of optoelectronic devices. It is proven difficult, however, to develop high-performance materials that combine the often incompatible properties of transparency and conductivity, especially for p-type doped materials. In this presentation, I will show our recent work where we have employed a large set of molecular semiconductors extracted from the Cambridge Structural Database to evaluate the likelihood of transparent conducting materials technology based on p-type doped molecular crystals. Candidates are identified imposing the condition of high HOMO energy level (for the material to be easily dopable), high charge carrier mobility (for the material to display large conductivity when doped) and a high threshold for energy absorption (for the material to absorb radiation only in the ultraviolet). The latest condition is found to be the most stringent criterion in a virtual screening protocol on a database composed of structures with sufficiently wide two-dimensional electronic bands. Calculation of excited-state energy is shown to be essential as the HOMO-LUMO gap cannot be reliably used to predict the transparency of this materials class. Molecular semiconductors with desirable mobility are transparent because they display either forbidden electronic transition(s) to the lower excited states or small exchange energy between the frontier orbitals. Both features are difficult to design but can be found in a good number of compounds through virtual screening.

Authors : Rada Savkina, Oleksij Smirnov, Tetyana ?ryshtab
Affiliations : V. Lashkaryov Institute of Semiconductors Physics, NAS of Ukraine, Nauky av.41, 03028 Kyiv, Ukraine V. Lashkaryov Institute of Semiconductors Physics, NAS of Ukraine, Nauky av.41, 03028 Kyiv, Ukraine Instituto Politécnico Nacional - ESFM, Department of Physics, 07738 Mexico D.F., Mexico

Resume : There are known the losses due to the spectral distribution of solar radiation, where a significant part of the photons has an energy greater than that required for photogeneration of charge carriers and the residual energy is converted into kinetic energy, that is, into heat. Our main idea is in the combination of photo- and thermo-electrical properties in a single hybrid system to the most efficient conversion of solar energy as well as using the supercapacitor function to increase the energy density of the system and energy storage. We propose concept of the photo-thermoelectric cells - a double (photo- and thermo-) highly efficient convertor of sunlight energy based on transitional metal oxide (Fe2O3 and Cr2O3) nanoscale amorphous films with a thickness of (10 ..100) nm on Si substrates, combined into a hybrid material with organic photo- and thermal - active conjugated polymers (poly-3-hexylthiophene (P3HT), poly (3,4) -ethylene dioxythiophene, polystyrene sulfonate (PEDOT: PSS), namely P3HT/Fe2O3 and PEDOT: PSS/Fe2O3, respectively). The combination of silicon with a layered system of organometallic compounds will make it possible to obtain a new multifunctional structure for solar energy converters. Additional function of the proposed converter is collecting and storing energy by supercapacitors. The concept of energy storage is based on the combination of iron oxide with carbon nanomaterials.

11:30 Discussion    
Energy Materials : Dawid Janas, Yogendra Kumar Mishra, Reza Abolhassani
Authors : Alberto Vomiero
Affiliations : 1) Division of Materials Science, Department of Engineering Sciences and Mathematics, Luleå University of Technology, SE-971 87 Luleå, Sweden. E - mail 2) Department of Molecular Sciences and Nanosystems, Ca' Foscari University of Venice, Via Torino 155, 30172 Venezia Mestre, Italy. E - mail

Resume : Composite nanostructures can be efficiently applied for Sunlight detection and conversion and, more in general, for energy harvesting and generation of solar fuels. In most of the applied systems, like photodetectors, excitonic solar cells and (photo)-electrochemical cells to produce solar fuels, nanomaterials can play a critical role in boosting photoconversion efficiency by ameliorating the processes of charge photogeneration, exciton dissociation and charge transport. Critical role in such processes is played by the structure and quality of the interface, which needs to be properly assembled to obtain the desired functionality. Several strategies can be pursued to maximize energy harvesting and storage, including broadening of light absorbance to reduce solar light losses, fastening exciton dissociation and charge injection from the photoactive medium to the charge transporting materials, reducing charge recombination during charge transport and collection at the electrodes. In this lecture, a few examples of application of nanocomposites will be discussed, including all-oxide coaxial p-n junction nanowire photodetectors and solar cells, core-shell quantum dot fluorophores for high-efficiency luminescent solar concentrators, composite sulfides for hydrogen generation, and oriented carbon nanotube forest dispersed in polymer matrix as efficient low-temperature thermoelectric composite. Emphasis will be given to the role of interface engineering in improving the efficiency of energy conversion in different systems, spanning from electric power generation from Sunlight, to chemical fuel production, to conversion of heat lost through thermoelectric materials. Keywords: p-n junction nanowires, quantum dots, interfacial properties, luminescent solar concentrators, solar cells, low temperature thermoelectric composites.

Authors : F. Lübkemann, J. F. Miethe, D. Zámbó, R. Anselmann, P. Rusch, A. Schlosser, T. Kodanek, D. Dorfs, N. C. Bigall
Affiliations : Leibniz Universität Hannover, Institute of Physical Chemistry and Electrochemistry and Cluster of Excellence PhoenixD (Photonics, Optics, and Engineering – Innovation Across Disciplines), Hannover, Germany

Resume : The spotlight of current research is on the synthesis of nanoparticles with various shapes, sizes, and optical properties as well as on their assembly into three-dimensional structures commonly known as aerogels. Nowadays, the assembly of NPs into meso- or macrostructures is of high interest and the structures can be used in different fields, e.g. photocatalysis, catalysis and sensing.[1] Moreover, inkjet printing is a common technique to deposit nanoparticles on different substrates and enables a lateral structuring. Here, the patterning of 3D nanoparticle-based CdSe/CdS aerogel-like networks on conducting surfaces via inkjet printing of an aqueous nano-ink is presented.[2,3] The main focus is on the implementation of the conventional nanoparticle-based gelation process in a commercial office printing system. By simultaneously printing the aqueous nano-ink and a destabilization agent, an aerogel-like network¬ coated electrode surface can be achieved, which enables the manufacturing of 3D nanoparticle-based network-coated (photo)electrodes for applications in (photo)electrochemistry. Additionally, the charge-carrier mobility within the printed three-dimensional semiconductor nanoparticle based networks was investigated by spectroelectrochemical measurements.[3,4] [1] P. Rusch, D. Zámbó, N. C. Bigall, Acc. Chem. Res., 2020, 53, 10, 2414–2424. [2] F. Lübkemann, R. Anselmann, T. Kodanek, N. C. Bigall, Chemie Ing. Tech. 2017, 89, 807–813. [3] F. Lübkemann, J. F. Miethe, F. Steinbach, P. Rusch, A. Schlosser, D. Zámbó, T. Heinemeyer, D. Natke, D. Zok, D. Dorfs, et al., Small 2019, 15, 1902186. [4] J. F. Miethe, F. Lübkemann, A. Schlosser, D. Dorfs, N. C. Bigall, Langmuir 2020, 36, 4757–4765.

Authors : Sugato Hajra* (1), Manisha Sahu (1), Hoe Joon Kim (1)
Affiliations : (1) Daegu Gyeongbuk Institute of Science and Technology, Republic of Korea.

Resume : Harvesting mechanical energy from surroundings has a high potential to act as a power source for micro/nano-devices. The triboelectrification and electrostatic induction are followed by the triboelectric nanogenerator (TENG) to produce an electrical output. The novel materials are needed to investigate the usage in the fabrication of TENG and also extend the conventional triboelectric series. It further improves the performance of a TENG. Herein, a zeolite imidazole framework (ZIF-67) was synthesized using a room temperature solvent-assisted method. The structural and chemical properties are evaluated by the material characterization tools. Further, a simple vertical contact mode S-shaped TENG device (S-TENG) was fabricated by an additive manufacturing approach. The ZIF-67 acted as a positive triboelectric layer while the Kapton/Teflon/PDMS acted as a negative triboelectric layer. The multi-unit S-TENG device was further utilized as self-powered recognition of the various gaits using a digital signal processing approach. The S-TENG (ZIF-67 and Teflon) generates a voltage of 118 V, a current of 1.7 µA, and a power density of 15 µW/cm2 at load resistance of 50 MΩ. The gait analysis and the digital signal processing route could help to shed light upon the various gait patterns for the prevention of falls or injuries among the small kids in playschool. Further, the S-TENG device was utilized to charge a commercial capacitor for powering a wristwatch. The S-TENG was integrated into a robotics gripper and various objects such as foam ball, golf ball, and silicone ball were recognized by the holding and release of the ball by the robotic gripper paves the way to various self-powered object identification.

Authors : Tim Erichlandwehr, Franziska M. Esmek, Dennis Mors, Irene Fernandez-Cuesta
Affiliations : Institut für Nanostruktur- und Festkörperphysik, Universität Hamburg, Germany: Tim Erichlandwehr; Franziska M. Esmek; Dennis Mors; Irene Fernandez-Cuesta Deutsches Elektronen-Synchroton (DESY), Hamburg, Germany: Tim Erichlandwehr

Resume : On-chip DNA optical mapping is a fast, high throughput and inexpensive alternative for DNA analysis. Currently, optical mapping techniques operate in the 1 kbp resolution range, which could be further improved, for example with more precise control of the transport dynamics at the micro-nano interface. Furthermore, getting the DNA molecules to flow into the nanochannels requires using electrophoresis or pressure. To avoid this, we studied different nanostructured channel inlet and outlet topographies to understand their influence on DNA flow dynamics. By focusing a laser spot on the nanochannel, a length specific DNA fluorescence signal can be detected. Influences of different topographies then result in varied mean signal durations, as DNA molecules get accelerated or decelerated. This leads, on one hand, to spontaneous flow of molecules in the nanochannels. On the other, to an increased throughput of molecules into the nanochannels. Furthermore, slowing down the molecules allows for higher resolution in optical mapping applications. Furthermore, pillar structures were incorporated at channel-openings to facilitate additional decelerating factors on DNA molecules. With the help of these strategies, we were able to significantly slow down the DNA molecules flowing through the nanochannels. In this study we studied the influence of different topographies on the flow and stretching of DNA molecules in nanochannels, for resolution enhancing capabilities through improved control of DNA flow dynamics.The molecules are labeled and read out by a laser, as they flow through a nanochannel. Using 3D funnel inlets, and squared staggered outlets we were able to slow down the molecules by a factor of 3x. By adding nanopillars in the inlets we can slow down the DNA molecules even further.

Affiliations : School of Engineering and Material Science and Materials Research Institute, Queen Mary University of London, London, E1 4NS

Resume : With the consumption of fossil fuel and the increasing awareness of environmental protection, more and more efforts are being put into the development of renewable and clean energy. Mechanical energy is the one of the most abundant and accessible energy sources, and has been widely harvested by large-scale technologies such as wind power or tidal stream generators. Piezoelectric nanogenerators (PNGs) provide a potential way to convert small mechanical energy such as body motion or vibration into electricity, which can be used to power small portable electronics, medical bio implants, remote wireless sensors etc.1 P-n junction based ZnO PNGs have attracted interest due to their good flexibility, simple manufacture process and low raw material cost. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonic acid) (PEDOT:PSS), has been employed in the p-n junction based ZnO nanogenerators owing to its good film-forming properties, high transparency, tunable conductivity, and excellent thermal stability. P-type PEDOT:PSS can form a p-n junction with n-type ZnO nanorods, which slows down the screening of the piezoelectric polarisation to generate the output voltage.2 Therefore, optimizing the conductive property of PEDOT:PSS is a potential way to improve the performance of PNG by controlling screening of piezoelectric polarisation and reducing internal resistance of the device. In this work, ethylene glycol (EG) is doped in to the p-type PEDOT:PSS layer in ZnO PNGs to modify the conductivity of PEDOT:PSS. It is found that modest EG doping can effectively enhance the conductivity of the PEDOT:PSS layer and reduce the internal resistance of PNG device. However, devices without EG doping or using excessed EG doping can result in reduced conductivity and worse performance.

Authors : Hamed Abdolmaleki, Shweta Agarwala
Affiliations : Electrical Engineering Department, Aarhus University

Resume : In the last two decades, ferroelectric polymers have triggered interest in academia and industry due to their flexibility, biocompatibility, facile processibility, high dielectric breakdown strength, and low acoustic impedance. Despite these promising features, lower piezoelectric constant, and dielectric permittivity of ferroelectric polymers in comparison to their inorganic counterparts are the main impediments hindering their application in device fabrication. The mentioned drawbacks led to numerous efforts to enhance the performance of ferroelectric polymers through various strategies. Nanofiller strategy is a method that has shown great promise in improving piezoelectric constant and polarization of PVDF-based polymers. In this work we investigated the influence of amine-functionalized graphene oxide (AGO) on ferroelectric, piezoelectric, and dielectric properties of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE). It was observed that by incorporation of only 0,1 w% AGO in PVDF-TrFE matrix the remnant polarization increased to 10.92 ?C/cm2 from 8.11 ?C/cm2 for pristine PVDF-TrFE, which is the highest reported value for the polymer with non-piezoelectric filler. Furthermore, the piezoelectric and dielectric constants have increased to -46 nm/V and 17,9 from -33 nm/V and 14,7, respectively.

14:45 Discussion    
Energy Technologies : Yogendra Kumar Mishra, Dawid Janas, Vomiero Alberto
Authors : Jiwon Park, Eunji Lee*
Affiliations : School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005, Republic of Korea

Resume : Gallium-based liquid metals (LMs) are recognized as an emerging material due to their unusual combination of metallic and fluidic properties, which could be used in a variety of fields such as flexible electronics, catalysis, soft composites, and biomedicine. Compared to pristine LM, LM-nanoparticles (-NPs) can lower its freezing and melting temperatures, securing facile solution-processability. This superior characteristic expands its applicability in a wide range of operating temperatures for LM-based electronics. Furthermore, LM are easily dispersed in eco-friendly solvents including alcohol and water without any mechanical treatments. However, the fabrication of LM-NPs having a long colloidal stability is still challenging due to the high density and surface energy of LM. Herein, we report the facile and effective fabrication of water-dispersed LM-NPs through emulsification-induced self-assembly of the conjugated polymer. The LM-NPs are generated through the chemical instability occurring at the oil/water interface of emulsion droplet during oil evaporation in water phase. The resultant NPs were encapsulated by conjugated polymers in water (as denoted LM-NP-water ink). This method using chemical instability of droplets allow us to modify the functionalities of LM-NP-water ink by addition of any polymers into droplets. The functional water-inks are successfully generated regardless of the polymer configuration such as rigidity, stability, or planarity. For example, LM-NP-water ink stabilized by catechol-based polymers shows the strong adhesion on any substrates. This research can provide a facile strategy for the preparation of customized LM-NP-water ink that can be applied to soft stretchable electronics with eco-friendly processing.

Authors : Cavinato, L.M.* (1), Millán, G. (2), Dr. Fresta, E. (1), Dr. Fernández-Cestau, J. (1) Prof. Dr. Lalinde, E. (2), Prof. Dr. Berenguer, J.R. (2), Prof. Dr. Costa, R.D. (1) * lead presenter
Affiliations : (1) Chair of Biogenic Functional Materials - Technical University of Munich, Schulgasse 22, 94315 Straubing, Germany (2) Departamento de Química-Centro de Investigación en Síntesis Química (CISQ) - Universidad de La Rioja, Madre de Dios 53, 26006 Logroño, Spain

Resume : Light-emitting electrochemical cells (LECs) are the simplest and cheapest solid-state lighting technology for soft and/or single-use lighting applications, such as decoration, labelling, phototherapy, etc. However, a major concern is the transition towards sustainable devices meeting Green Photonics requirements. To date, huge efforts have been carried out to implement eco-friendly emitters (organometallic complexes, small molecules, etc.),[1] while little consideration has been placed on green electrolytes: i) biodegradable polymers and ii) bio-hybrids based on DNA. Here, bio-electrolyte-based LECs always exhibited moderate performances: 3.2 cd/A@262 cd/m2 and 1 cd/A@1500 cd/m2 for devices with biodegradable and bio-hybrid electrolytes, respectively.[2,3] In addition, they have been restricted to only conjugated polymer emitters. Finally, self-stability with respect to storage under ambient conditions and mechanical/ thermal stress have been neglected. This work shows a fresh approach to overcome these limits. Self-stable, highly efficient, and stable LECs with a novel biogenic cellulose-based electrolyte have been realized.[4] Versatility is confirmed by testing conjugated polymer, organometallic complex, and BN-doped nanographene[5] emitters. Both, the increase of roughness and decrease of photoluminescence response, are limited upon self-stability tests, while the charge injection process is enhanced due to high dielectric constants. Concerning device performance achieved in pulse mode, these LECs featured high luminance and efficacies values (e.g., 15 cd/A@3750 cd/m2 for conjugated polymers) representing an overall ca. 4-fold enhancement with respect to their respective reference devices based on traditional electrolytes. For the first time, a novel biogenic electrolyte has been used without compromising device performance, regardless the type of emitter. What is more, this work reinforces the relevance of carbohydrate-based materials/ electrolytes not only for energy-related applications, but also for lighting purposes. References: 1 E. Fresta et al., J. Mater. Chem. C, 2017, 5, 5643 2 J. Zimmermann, et al., Adv. Funct. Mater., 2018, 28, 1705795 3 S. Tekoglu, et al., Adv. Sustain. Syst., 2021, 5, 2000203 4 L.M. Cavinato, et al., Adv. Funct. Mater., 2022, submitted 5 E. Fresta, et al., Adv. Funct. Mater., 2020, 30, 1906830

Authors : Harikrishnan G.*(1), Arijit Kayal (1), K. Bandopadhyay (2), K. Kolodziejak (2), Dorota A. Pawlak (2,3), Joy Mitra (1)
Affiliations : (1) Indian Institute of Science Education and Research, Thiruvananthapuram, India; (2) ENSEMBLE3 Centre of Excellence, Warsaw, Poland; (3) Łukasiewicz – Institute of Microelectronics and Photonics, Warsaw, Poland

Resume : Titanium dioxide (TiO2) is material with diverse applications, from cosmetics and pigments to photovoltaic cells. Many of these applications benefit from TiO2’s large band gap (3.3 eV) and high refractive index. However, their potential in optoelectronic devices and photocatalytic activity are limited by the dynamics of electron-hole recombination and carrier mobility. Some success in decreasing recombination rate has been achieved via nanostructuring and ripening of TiO2 and coupling of metal nanoparticles (NPs) to TiO2, which have also contributed to increased mobility. Still efficient metal NPs-TiO2 coupling is nontrivial, complicated by the defect laden interfaces that are dictated by the formation process. Therein lies the significance of eutectic hybrid composites (e.g. Ni-TiO2) that display several advantages over homogenized nanostructured systems, like high crystallinity of the component and sharp interfaces, opening novel possibilities in materials engineering. Here we explore the optoelectronic properties of Ni–TiO2 eutectics, where high aspect ratio TiO2 nanowires are axially decorated with nodular Ni NPs. The higher work function of Ni (5.01 eV) compared TiO2’s electron affinity (4.21 eV) and the ensuing equilibrium band crossover at the junctions ensures separation of photogenerated carriers. Upon suitable illumination photogenerated electrons migrate from TiO2 to Ni making the NPs electron-rich and TiO2 hole rich. The plasmonic near field amplification by Ni NPs, further aiding the photogeneration efficiency. The enhanced carrier generation efficiency and separation is anticipated to increase the overall efficiency of any ensuing photoactive device. Realization of the above and selective extraction of carriers from the hybrid architecture is the challenge addressed here. Selective extraction of the electrons and holes may be effected using n-type and p-type polymers allowing preferential conduction of holes through the TiO2 nanowire backbone. Photovoltaic characteristics of prototype devices fabricated using PEDOT:PSS and (a)TiO2, (b)NiTiO3 and (c)NiNP-TiO2 eutectic heterostructures show that the UV photoresponse of the devices are ordered as c > b > a. The results not only provide proof-of-concept of the above design, employing the novel eutectic architecture but also provides better understanding of photogeneration of carriers and their control. The architecture effectively exploits the nanostructuring process and opportunistically chosen material properties to increase the efficiency of devices. Overall, charge generation, segregation and transport mechanism are enabled by the novel nanowire-nodule architecture of the hybrid composite that allows co-incidence and exploitation of multi-physics effects i.e. plasmonic enhancement, photogeneration, charge segregation, rectification and controlled transport finally engineering the high-performance device properties that are warranted.

Authors : Debalina Deb
Affiliations : CSIR Research Associate, The Solid State and Structural Chemistry Unit – SSCU, IISc, Bengaluru

Resume : Hexafluoropropylene copolymer (P(VDF-HFP))-based “active” polymer membranes are prepared by entrapping different extent of pyrrolidinium ionic liquid-based nanofluid (ionanofluid). X-ray diffraction (XRD), differential scanning calorimetry (DSC), and Fourier transform infrared (FT-IR) spectroscopy are implemented to characterize the membranes. The study reveals that ionanofluid improves the electroactive phase nucleation of P(VDF-HFP) and suppresses the membranes’ crystallinity. SEM micrographs and butanol absorption study indicate that ionanofluid improves the electrolyte uptake ability and facilitates forming unified ion-conducting channels within the membranes. The 50 wt% ionanofluid (INF) incorporated gel-polymer electrolyte (GPE) exhibits the highest room-temperature ionic conductivity (2.33 × 10−3 S cm−1 at 25 °C), a high lithium-ion transference number (tLi+∼0.6), superior electrochemical stability window up to ~ 5.3 V (vs. Li/Li+) and excellent interfacial compatibility with the lithium electrode. The LiFePO4/Li battery comprising INF-based GPE demonstrates good C-rate performance and excellent cycling stability with a discharge capacity of ~ 156 mAh g−1 and ~ 116 mAh g−1 at C/5 and 2 C rates, respectively, and capacity retention of > 95% after 50 cycles at C/5 rate.

Authors : Redko R.1,2, Milenin G.1, Zayac M.1, Boiko V.1, Lytvyn P.1, Redko S.1
Affiliations : 1V. Lashkaryov Institute of Semiconductor Physics of the National Academy of Sciences of Ukraine; 2State University of Telecommunications

Resume : AlN films were obtained by high-frequency reactive magnetron sputtering of an aluminum target in a gas mixture of Ar and N2 on an upgraded industrial plant ?Katod 1M?. An industrial frequency of 13.56 MHz was used. In order to obtain the more structured film, the power of the high-frequency discharge was about 700 W (target diameter was 16 cm). The thickness of the films was controlled during the covering of the film on the substrate by the deposition rate, which was 1.5-3 nm/min. So, the grown AlN films could be with the thickness of 0.5 - 3 ?m. As the substrate was used n-Si (111) with a resistivity (2 - 3)?10-3 Ohm?cm (electron concentration N was 2.5?1019 cm-3). Before the deposition of the AlN film, the substrate was chemically etched and heated. Clear green rings (? = 510 nm), which alternate with black rings are observed on micro-photos of the surface of the studied samples. They are visualized in specific places on surface of the sample. The diameter of the observed rings varies in the range of 5-10 ?m for different samples. Moreover, depending on the thickness of the AlN film, a different number of the rings is visualized: a larger number at a thin film (~1?m) (5-6 rings) and a smaller number at the thickness of 3 ?m (3-4 rings). Detailed analysis of physical origin of obtained features has shown interference nature of rings. Ellipsometric measurements have showed that for our selected wavelength n?1.6. AFM measurement testifies that places of visualized rings are micro-hills with highs of 500-700 nm. These hills are almost perfectly spherical shape. Such thin AlN film could be applied as effective micro-lenses covering for Si-based solar cells to increase their efficiency.

Authors : O.O. Bondarenko, R.M. Balabai, I.V. Bilynskyi
Affiliations : Kryvyi Rih State Pedagogical University

Resume : Coordination polymers (CP`s, a kind of supramolecular polymers) are highly molecular compounds composed of repeating organic molecules and metal ions linked by intermolecular interactions. One of the strongest types of such interactions is the coordination bond between donor centers in an organic molecule (L) and a metal ion (M). If the ligand contains several donor sites, located in a molecule divergently, then it can participate in the binding of several metal centers into one supermolecule. The translation of such linked (L-M) fragments in one, two or three directions leads to the formation of 1D, 2D or 3D CP. CP`s are functional hybrid materials with original redox, luminescent, nonlinear optical, magnetic, sorption, catalytic, ion exchange, sensory and other properties. [Michael Tran, Katelyn Kline, Ying Qin, et al. / 2D coordination polymers: Design guidelines and materials perspective // Appl. Phys. Rev. 6, 041311 (2019)]. Most of the currently known coordination polymers are constructed using di- and polycarboxylic acids as ligands. Coordination polymers based on di- and three phosphinic acids are currently represented to a large extent compounds containing a flexible spacer between phosphorus atoms, which ensures the conformational mobility of such systems. The complexing properties of arendiyl bisphosphinic acids remain practically unexplored [Gagnon, K.J. Conventional and Unconventional Metal-Organic Frameworks Based on Phosphonate Ligands: MOFs and UMOFs / K.J. Gagnon, H.P. Perry, A. Clear?eld // Chem. Rev.? V. 112, 1034 (2012)]. This work is devoted to the theoretical study, using the methods of electron density functional, ab initio pseudopotential and the author's software [], of the one-dimensional and two-dimensional coordination polymers based on arendiyl bisphosphinic acids, study of their electronic-structural properties and charge states of donor centers in an organic molecule and a metal ion. The conditions for the formation of a two-dimensional layered structure and one-dimensional chains of coordination polymers are discussed.

17:00 Discussion and Closing Session    

No abstract for this day

No abstract for this day

Symposium organizers

Tolosa Hiribidea, 76 - 20018 Donostia - San Sebastián, Spain

+34 943 57 4045
Graziella MALANDRINOUniversità degli Studi di Catania

Dipartimento Scienze Chimiche, Viale Andrea Doria 6, 95125 Catania, Italy
Shashank MISHRAUniversité Claude Bernard Lyon 1, CNRS

IRCELYON-UMR 5256, 2 avenue Albert Einstein, 69626 Villeurbanne, France

+33 472 445 322
Yogendra Kumar MISHRA (Main organizer)Mads Clausen Institute, University of Southern Denmark

Alsion 2, 6400, Sønderborg, Denmark