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2017 Fall Meeting



Silicon, Germanium, Diamond and Carbon nanostructures and their nanocomposites with other materials

Nanocomposites of group-IV nanomaterials combined with metal, dielectric, polymer (etc.) materials are currently investigated from technological, theoretical and experimental point of view with the aim to improve inherent limitations and gain new functionalities.


Group IV materials (C, Si, Ge) are between the most abundant and technologically important elements. The interest to study the group IV-based nanostructures is rapidly growing with motivation to use them for various application extending from electronics, photonics, photovoltaics, sensorics up to bio-medicine. Most of such applications require creation of composite structures of group-IV nanostructures with dielectrics, polymers, plasmonic structures etc. This symposium covers many intensely studied forms of group-IV nanostructures, namely: Si and Ge nanocrystals and nanowires, silicon carbide and carbon dots and nanodiamonds. Basic characteristics of these materials are already well known and some limitations become evident: For example relatively low absorption cross section, limited luminescence yield, problems with doping and energy transport, unstable surface termination and defects etc. One possible way to overcome limitations of group-IV nanomaterials is creation of nanocomposite structures with metals (Au, Ag, Pt nanocrystals and nanorods), organic materials (like conductive polymers, fluorescent dyes, ligands etc.). The symposium will address the field of group-IV such composite structures from technological, theoretical and experimental point of view.

Hot topics to be covered by the symposium:

  • Conjugates of nanocrystals with plasmonic nanostructures
  • Experimental studies of single nanobjects and nanoconjugates
  • Embedding nanostructures in photonic crystals, microcavities, waveguides etc.
  • Doping and defects in group-IV nanostructures
  • Influence of interface effects – surface functionalization, strain, charge transfer etc. 
  • Applications in biology studies, medicine, bio-imaging and sensing 
  • Theoretical description and modelling of nanostructures and composites
  • Fabrication techniques (both bottom-up and top-down)
  • Device design and fabrication with nanocomposites
  • Physics of quantum colour centres 
  • Quantum sensing and imaging at nanoscale Single molecular NMR

List of invited speakers (confirmed)

  • Brian Korgel, University of Texas, Austin, USA
  • Ivan Marri, University of Modena, Italy
  • Petr Cigler, Institute of Org. Chemistry & Biochemistry, AVCR, Czechia
  • Ilya Sychugov, Royal Institute of Technology, Stockholm, Sweden
  • Daniel Hiller, IMTEK, U. Freiburg, Germany
  • Lukáš Ondič, Institute of Physics, AVCR, Prague, Czechia
  • Christoph Delerue, University of Lille, France
  • Naoki Fukata, NIMS, Tsukuba, Japan
  • Detlev Grützmacher, Forschungszentrum  Julich, Germany
  • Anke Krüger, U. Würzburg, Germany 
  • Li Quan , The Chinese University of Hong Kong, China

and more to be specified later

List of scientific committee members (confirmed)

  • Margit Zacharias, IMTEK, U. Freiburg, Germany
  • Marie Hubalek Kalbacova, Charles University, Prague, Czechia 
  • Romuald Beck, Warsaw Technical University, Poland 
  • Tom Gregorkiewicz, University of Amsterdam, Netherlands
  • Bohuslav Rezek, Institute of Physics, ASCR, Prague, Czechia
  • Xiandong Pi, Zhejiang University, China
  • Francesco Priolo, University of Catania, Italy
  • Ivan Pelant, Institute of Physics, ASCR, Prague, Czechia
  • Leonid Khriachtchev, U. Helsinki, Finland
  • Salvatore Mirabella, IMM CNR, Catania, Italy
  • Sergey V. Gaponenko, Stepanov Institute of Physics, Minsk, Belarus
  • Jean Francois Roch, Laboratoire Aimé Cotton, France
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Si nanocrystals from single dot to assemblies : Valenta, Hiller
Authors : Yixuan Yu, Adrien Guillaussier, Brian A. Korgel
Affiliations : McKetta Department of Chemical Engineering and Texas Materials Institute The University of Texas at Austin Austin, TX 78712 USA

Resume : Silicon nanocrystals can now be made with a high degree of uniformity and assembled into a variety of structures. For example, uniform silicon (Si) nanocrystals with cuboctahedral shape, passivated with 1-dodecene capping ligands assemble into face-centered cubic (FCC) superlattices with orientational order. Transmission electron microscopy (TEM), electron diffraction and grazing incidence wide angle and small angle X-ray scattering (GISAXS and GIWAXS) show that the preferred orientation of these soft cuboctahedra depends on the orientation of the superlattices on the substrate, indicating that the interactions with the substrate and assembly kinetics can influence the orientation of faceted nanocrystals in superlattices.1 These superlattices exhibit structure-dependent solid-solid phase transitions of the Si nanocrystals under pressure. Application of a quasi-uniaxial pressure was found to induce the formation of a new Si phase with diatomic body-centered cubic (BCC) structure and a lattice constant of 4.08 Å at 9.5 GPa. We have also used Si nanocrystals to create substrate-free self-supporting bubble assemblies, which can be used to study optical phenonmena in the absence of solvent and substrate effects.

Authors : Hiroshi Sugimoto, Minoru Fujii
Affiliations : Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan

Resume : Si forms not only the backbone of microelectronics technology but also gains in significance for photonics when its size is down to nanoscale. Depending on the size (1-1000 nm), Si nanostructures exhibit different optical responses. In Si crystals with sub-10 nm in size, the quantum confinement effect enables the efficient photoluminescence (PL) and facilitate the applications as light emitters. In addition, crystalline Si nanosphere (NS) with 100-250 nm in diameter shows the Mie resonance in the visible to near-IR range due to the high refractive index of Si, which can be utilized as optically resonant materials analogous to plasmonic structures. In this work, we develop the colloidal dispersion of Si NSs with a size range of 1 to 250 nm from the same starting material that is a Si-rich borophosphosilicate (BPSG) glass. The BPSG glasses are annealed at 900-1600oC in a N2 atmosphere to grow Si NSs with different sizes and Si NSs are liberated in solution by hydrofluoric acid etching. The NSs are dispersible in water due to the inorganic surface modification.[1] We demonstrate the efficient and size-tunable PL in the red to near-IR range for Si NSs smaller than 10 nm. We also show the strong light scattering of Si NSs with 100-250 nm in diameter due to the Mie resonance.[1] In the presentation, we will discuss the detailed optical properties and demonstrate potential applications in bio-photonics. [1] H. Sugimoto, Adv. Opt. Mater. (2017) 10.1002/adom.201700332

Authors : M. Greben and J. Valenta
Affiliations : Faculty of Mathematics & Physics, Charles University, Prague, Czechia

Resume : Nanocrystalline silicon (nc-Si) constrains the exciton in a limited space region that allows to control optical transition states by tuning the size of nanocrystals (quantum confinement effect (QCE)). This property of nc-Si can found a bunch of applications in photonic and photovoltaic devices. Here we studied time-resolved (TR) photoluminescence (PL) decay kinetics of dodecyl-passivated colloidal silicon nanocrystals (Si NCs). Though it was possible to fit PL transients by conventional stretched exponential (SE) function, we tested other decay models. The average PL decay lifetimes were confirmed to be independent of a fit model. The exponential decrease of lifetimes with increasing emission photon energy revealed QCE that is shown to be in agreement with theoretical calculations by the envelope function approximation (EFA) method. Unlike lifetime, the energy dependence of dispersion factor (SE fits) is not monotonous with a sudden change at 1.4–1.5 eV. Beside this energy interval, there is an exponential probing of dispersion factor by energy. At room temperature, the emission of individual Si NCs (homogeneous linewidth) is quite broad and influence the ensemble PL spectrum as well as PL transients. However, this effect is usually omitted when analyzing TR PL experiments. In this work we introduce the unique procedure to resolve size-selected decays (originated from NCs of a certain size) from spectrally resolved ones (correspond to a selected detection energy). Thanks to this it became possible to prove the perfect 100% internal quantum efficiency (QE) of Si NCs emitting around 1.5 eV that is the key point of this work. In addition, the average internal and external QE were compared and the difference between them was assigned to a fraction of “dark” (absorbing but non-emitting) Si NCs in the ensemble. For the first time it was estimated the fraction of bright Si NCs in colloidal solution that occurred to be roughly two times larger than in ensemble of oxide embedded Si NCs[1]. [1] J. Valenta et al., Appl. Phys. Lett. 105 (2014) 243107.

Authors : Ilya Sychugov, Aleksandrs Marinins, Federico Pevere, Jan Linnros
Affiliations : KTH - Royal Institute of Technology

Resume : Emission and absorption states in individual silicon nanocrystals were studied by temperature-dependent photoluminescence and photoluminescence excitation experiments. Both close-to-spherical and elongated particles were probed and the results were compared to first-principle calculation. The comparison revealed good agreement with theory, where the intermixing of direct and indirect states in nanostructured silicon takes place as a function of nanoparticle size, shape and photon energy [1,2]. An important feature of such nanoparticles is a large Stokes shift, stemming from the bulk material energy structure. This property makes these fluorophores good candidates for some light converting applications, such as in luminescent solar concentrators. We have prepared hybrid materials with different polymers [3,4], where enhancement of quantum yield up to 60-70% was recorded in case of off-stochiometry thiols, attributed to dangling bond passivation by polymer radicals. The resulting nanoparticle-polymer hybrids were successfully integrated with glass and their stability over months was demonstrated [5]. [1] I. Sychugov, F. Pevere, J. W. Luo, A. Zunger, and J. Linnros, Phys. Rev. B 93, 161413 (R) (2016). [2] I. Sychugov, F. Sangghaleh, B. Bruhn, F. Pevere, J.-W. Luo, A. Zunger, and J. Linnros, Nano Lett. 16, 7937 (2016). [3] A. Marinins, Z. Yang, H. Chen, J. Linnros, J. G. C. Veinot, S. Popov, and I. Sychugov, ACS Photonics 3, 1575 (2016). [4] Y. Li, S. Yu, J. G. C. Veinot, J. Linnros, L. Berglund, and I. Sychugov, Adv.Opt.Mat. 5, 1600834 (2017). [5] A. Marinins, R. Shafagh, W. Van der Wijngaart, T. Haraldsson, J. Linnros, J. G. C. Veinot, S. Popov, and I. Sychugov, submitted (2017).

Group-IV photonics : Fujii, Sychugov
Authors : Detlev Grützmacher1, Dan M. Buca1, Daniela Stange1, Nils von den Driesch1, Thomas Zabel2, Hans Sigg2
Affiliations : 1 Peter Grünberg Institute and JARA-FIT, Forschungszentrum Jülich, Germany; 2 Laboratory for Micro and Nanotechnology, Paul Scherrer Institute, Switzerland

Resume : The group IV alloy GeSn provide a direct band gap for Sn concentration above ~8%, which is far beyond the solid solubility limit of ~1%. Recently high quality GeSn alloys with Sn concentrations up to 14.5% could be grown by reactive gas source epitaxy. The GeSn films have a direct band gap, in the range of 0.48-0.63 eV for Sn concentrations ranging from 14.5 to 8.5%, respectively. Thus, GeSn may pave the road for the integration of optoelectronic circuitry on Si (100) substrates. Optically pumped laser in the Fabry Perot as well as microdisc geometry have been fabricated from SiGeSn double heterostructures and SiGeSn/GeSn multiple quantum wells (MQW) on Ge virtual substrates. The threshold required to achieve lasing dropped from ~300 kW/cm2 for a thick GeSn film to about 30 kW/cm2 for a MQW structure. This can be attributed to reduced optical losses due to surface scattering as well as to the reduced number of states in the multiple quantum wells. The very small effective mass of electrons in the Г valley compared to large mass in the L valley require careful MQW design in order to maintain a direct band gap. To achieve electrically pumped lasing double hetero- and MQW-structures have been grown using SiGeSn cladding and barrier layers. The SiGeSn cladding layers have been partially doped to achieve p-i-n junctions. First devices have been fabricated showing a superior electroluminescence efficiency of MQW structures.

Authors : B. Pivac1, P. Dubček1, J. Dasović1, S. Bernstorff2
Affiliations : 1 Ruđer Bošković Institute, Bijenička 54, 10000 Zagreb, Croatia 2Elettra-Sincrotrone Trieste, SS 14, km 163.5, Basovizza (TS), Italy,

Resume : Germanium nanoparticles or quantum dots (QDs) embedded in transparent dielectric matrix have properties radically different from the bulk semiconductor and present a great potential for application in electronic and optoelectronic devices. Due to quantum confinement the optical bandgap of QDs based materials can be tuned by varying the nanoparticle size. These properties may be exploited for the fabrication of nanoscale electronic devices or advanced solar cells. In this work we explored the structural properties of QDs based superstructures for advanced solar cells. Magnetron cosputtering was used for deposition, and upon suitable thermal treatment a superstructure of QDs was formed. The structural properties were explored by GISAXS/GIWAXS analysis. Both the GISAXS and GIWAXS techniques were used to obtain the size of the grown objects and in addition, the Porod tail was analyzed in the GISAXS pattern in order to obtain information on the layer close to the Ge QD / matrix interface. The interface transition Ge QD / matrix will be discussed. We shall show that such a layer affects the time resolved PL properties of the Ge dots.

Authors : Ivan Marri
Affiliations : CNR-Nano, Istituto Nanoscienze, Via Campi 213/a, 41125 Modena , Italy, and Dipartimento di Scienze e Metodi dell’Ingegneria, Università di Modena e Reggio Emilia, via Amendola 2 Pad. Morselli, I-42100 Reggio Emilia, Italy

Resume : In recent years particular attention has been devoted to Silicon and Germanium nanocrystals and nanowires, a powerful class of nanostructures which is opening new substantial opportunities for optoelectronics and photovoltaics. These nanostructures are zero- and one-dimensional materials with diameter from few to some tenths of nanometers. They present unique size dependent electronic, optical and transport properties that are intrinsically associated with their low dimensionality and quantum confinement effect. In particular we have performed several ab-initio calculations in the framework of Density Functional Theory for free and matrix embedded Si nanocrystals and for Si-Ge nanocrystals and nanowires. Among the different results we will concentrate, here, on the role of doping in order to tune transport and/or optical and electronic properties. Moreover we will show how the interaction between different nanostructures is a promising route to foster the establishment of third generation photovoltaics due to multiple exciton generation.

Authors : Rami Khazaka1,2, Yann Bogumilowicz1,2, Denis Rouchon1,2, Hervé Boutry1,2, Zdenek Chalupa1,2, Valérie Lapras1,2, Bernard Prévitalli1,2, Sylvain David1,3, Patrice Gergaud1,2, Sylvain Maitrejean1,2
Affiliations : 1 Univ. Grenoble Alpes, F-38000 Grenoble, France; 2 CEA, LETI, MINATEC Campus, F-38054 Grenoble, France; 3 CNRS, LTM, F-38000 Grenoble, France

Resume : We report on the confined selective lateral growth of 16-nm-thick Ge on Si. Confinement was achieved between a top SiO2 layer and the buried oxide of an SOI substrate, the top Si layer of the SOI substrate serving as the template for the Ge epitaxial growth. 300 mm reduced pressure chemical vapor deposition reactor has been used. Firstly, the wafers fabrication will be described. Afterwards, we will show that the Si etching conditions play a crucial role in determining the cavity shape. Later on, we will present our results on the Ge morphological and structural properties grown inside those cavities at different temperatures using SEM, AFM, µ Raman and TEM observations. SEM observations have shown a strong influence of the growth temperature on the growth front. Raman investigations have shown that, under specific growth conditions, fully relaxed Ge nanostructures can be obtained. AFM images reveal that the Ge roughness (below 1 nm) is predetermined by the Si/oxide interface roughness rather that the Ge growth conditions. Finally, TEM images show that the crystalline defects in the Ge nanostructures strongly depend on the crystalline orientation of the Si seed. Based on these findings and with further optimization of cavities shape, it could be possible to filter defects efficiently using this technique.

Poster Session : Nesladek, Valenta
Authors : Y.Auchynnikau, А.Voznyakovskii, A. Voznyakovskii, V.Liopo
Affiliations : Yanka Kupala Grodno State University, Grodno, Belarus Institute of Synthetic Rubber, St. Petersburg, Russia

Resume : The development of technology for manufacturing nanostructured substances in amounts that could suffice an interlaboratory research is a high priority task for the implementation of nanoproducts. The ultradispersed clusters of synthetic carbon are used as on extra component in polymeric materials. The substances have a high dispersity and surface activity. To study properties of mineral oils, modified ultradispersed clusters of synthetic carbon is of interest. The present activity is devoted to the research of the modifying influence of ultradispersed clusters of synthetic carbon on viscosity of the characteristic of mineral oils and their stability at various temperatures. While the preparation of diamond secondary suspensions not only statistic average sizes of particles should be taken into consideration, but also nanodiamond particle parameters of polydispersity too. Even a minor amount of large sized indestructible of particles aggregates markedly reduce the sedimentation resistance of suspensions. Sedimentary instable large aggregates are enriched with fine- and low-dispersed particles. Time of insonification in a complicated manner influences on the polydispersity curve of nanocarbon particles in suspensions.

Authors : Jeongje Moon 1) 2), Yoonjoong Kim 1), Doohyeok Lim 1), Kyeungmin Im 1), and Sangsig Kim 1)
Affiliations : 1) Department of Electrical Engineering, Korea University, Seoul 02841, Republic of Korea; 2) LED PKG Development Group, Samsung Electronics Co. Ltd., Gyeonggi-do 17113, Republic of Korea

Resume : Recently, nanowire (NW) field-effect transistors (FETs) have been studied as a way to overcome scaling limits of conventional MOSFETs. NW FETs with three-dimensional gate structures produce great short-channel effect immunity. However, it is hard to fabricate NW circuits as appropriate alignment of several NWs is very difficult. In order to realize practically NW circuits in very large scale integration (VLSI), studies on logic circuits consisting of multiple NWs are needed. In this study, silicon NWs (SiNWs) obtained by a top-down method which includes conventional photolithography and wet etching are aligned and assembled to prepare NW logic gates. Hence, we fabricate and investigate a SiNW NOR logic gate composed of a SiNW array on a bendable substrate. A SiNW NOR logic gate was fabricated with the combination of SiNWs with a diameter of 100 nm, a high-k Al2O3 gate dielectric, tungsten gate electrode and aluminum source/drain electrodes. The connection of two p-SiNW FETs in series and two n-SiNW FETs in parallel is required for these FETs to operate FETs as a two-input NOR logic gate. Our p- and n-SiNW FETs exhibit on/off current ratios of ~105 and 104, respectively. The exact NOR logic functionality is achieved with sufficiently high noise margins and a high voltage gain of ~4 at a low supply voltage of 1 V due to the superior electrical characteristics of each SiNW FETs. This study shows the potential of our bendable SiNW NOR logic gate for future bendable VLSI circuits.

Authors : Paramita Maiti,(*a,b) Puspendu Guha,(a,b) and Parlapalli Venkata Satyam(a,b)
Affiliations : (a) Institute of Physics, Sachivalaya Marg, Bhubaneswar-751005, Odisha, India (b) Homi Bhabha National Institute, Training School Complex, Anushakti Nagar, Mumbai 400085, India.

Resume : Surface reconstruction and in-plane diffusion and many other interesting properties of silicon substrate depend on substrate orientation. We recently showed the possibility of controlling the aspect ratio Au-Ag nano-alloy structures using Si (110) substrates {Ref:[2]} when grown under MBE conditions. Earlier, we also showed that high index planes, such as, Si (5 5 12), showed interesting graded SixGey hetero-epitaxial structures only under direct heating (i.e., by passing current through the substrates) {Ref: [3]}. In this work we have showed growth of anisotropic Si-Ge nanostructures and their shape evaluation as a function of temperature, both in direct heating mode and by resistive heating mode. Here, we have varied the substrate temperature from RT to 700 °C by resistive heating (RH) and direct heating (DH) modes. Before depositing Ge, the Si (110) substrate is cleaned by resistive heating followed by direct heating at 600 °C and flashing at 1200 °C. We observed the formation of faceted Ge island on Si when the substrate temperature was 550 °C RH. At 700 °C RH substrate temperature; faceted structures connected to each other and form long array of nanowires (≈ 50-80 µm long). But there is no faceted structure formed when we deposited Ge on cleaned Si in RT followed by post annealing at 550 °C. In the case of DH mode, faceted islands are formed at a very low current 0.5A. Then the elongated faceted Ge islands aligned along <110> of Si for 1.0A DH. On the same sample, square shaped Ge islands are also seen. Square structures are formed by joining the elongated faceted islands in the direct current flowing direction of the substrate. If the direct current is very high like 2.0A (equivalent temperature ≈ 650 °C measured by pyrometer), the material desorbed from side to the center of the square shaped islands. The role of the direction of the current on morphology during DH heating and the composition of the nanostructures will be discussed. So in conclusion we can say that there is a shape transition from faceted island to long nanowires for RH mode and 2 fold to 4 fold symmetry changes for DH mode. Ref: [1] P. Maiti et al., (under preparation, 2017). [2] Anjan Bhukta et al.,Appl. Surf. Sci. 407 (2017) 337-344 [3] J K Dash et al., J. Phys.: Condens. Matter 23 (2011) 135002

Authors : Jeuk Yoo1),2), Yoonjoong Kim1), Doohyeok Lim1), Sangsig Kim1)
Affiliations : 1) School of Electrical Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea; 2) Samsung Electronics Co., Ltd., Hwasung, Gyeonggi-do, 445-701, Republic of Korea

Resume : In complementary metal-oxide-semiconductor (CMOS) technology, the gate-to-source/drain overlap reduces not only the n- resistance but also the lateral electric field. Devices with larger overlaps have a higher gate capacitance. Nevertheless, some adequate overlap structures have relatively higher drivabilities (SS, ION/IOFF ratio) per gate capacitance. In this study, we examine the effect of the gate-to-source/drain overlap in silicon nanowire (SiNW) CMOS inverters on bendable substrates. SiNWs have superior electrical switching characteristics because their three-dimensional (3D) gate structures produce the excellent short-channel effect immunity. SiNWs were obtained from a silicon wafer using a conventional top-down CMOS-compatible technology, and they were then transferred onto the bendable substrate. The non-overlapped n- and p-SiNW exhibit ION/IOFF ratios of ~102 and ~104, respectively, and the overlapped n- and p-SiNW ION/IOFF ratio are ~104 and ~107, respectively. A voltage gain of the overlapped inverter and the non-overlapped inverter are 3.07 and 1.21 at a drain voltage (Vdd) of 1.0 V, respectively. Our overlapped inverters offer the high speed and high gain. Hence these devices are suitable for high speed logic circuits. In addition, they are expected to be active devices in low-power bendable systems due to their operation at supply voltages as low as 0.2 V.

Authors : A. Nikolenko (1), V. Strelchuk (1), B. Tsykaniuk (1), L. Fedorenko (1), P. Shepeliavyi (1), V. Melnyk (2), I. Olkhovyk (2), A. Kuzmich (3), M. Isaiev (3) and V. Neimash (2)
Affiliations : (1) V. Lashkaryov Institute of Semiconductor Physics of National Academy of Sciences of Ukraine, 41 Nauky pr., 03028 Kyiv, Ukraine (2) Institute of Physics of National Academy of Sciences of Ukraine, 46 Nauky pr., 03028 Kyiv, Ukraine (3) Faculty of Physics, Taras Shevchenko National University of Kyiv, 60 Volodymyrska St., 01601 Kyiv, Ukraine

Resume : Composites of silicon nanocrystals (nc-Si) in a matrix of amorphous Si (a-Si) are considered as promising material for the next generation of cascade quantum-dot-based solar cells. A quasi-direct-gap absorption mechanism, of the band gap dependence on the size of nc-Si, and resistance to Staebler–Wronski effect make this material a cheap and environmentally friendly alternative to AIIIBV semiconductors. We report on Raman study of controllable formation of nc-Si by a metal-induced crystallization (MIC) in thin film a-Si-Sn structures under varied regimes of pulsed laser irradiation. A relation between amorphous and crystalline phases, size and concentration of nc-Si were estimated in dependence on the power of laser pulses with duration of 10 ns and 150 µs and wavelength of 535 and 1070 nm. The threshold laser power initiating the MIT process is determined, and the role of photoionization in the formation and decomposition of the Si-Sn solution leading to the formation of nc-Si is evaluated. The possibility of an effective tin-induced transformation of a-Si into nc-Si phase during the irradiation time of 10 ns is demonstrated for the layer thickness of 200 nm. Theoretical analysis of spatial and time distributions of temperature within the laser-irradiated areas was performed. The estimated temperature corresponding to the onset of structural and phase modification was found to be close to Sn melting temperature, which confirms the MIC mechanism in the eutectic layer at Si–Sn interface consisting of cyclic repetition of the processes of formation and decay of the Si–Sn solution [1]. 1. V. Neimash et. al. J. Appl. Phys. 114, 213104 (2013).

Authors : Andrei Babin, Alexander Grigorenko, Alexander Gvozdev, Valery Kopachevsky, Alexander Kudryakov, Sergej Shashkov
Affiliations : SOL Instruments Ltd., 58-10, Nezalezhnasti av., Minsk 220005 Belarus

Resume : Confocal Raman microscopy is a widely accepted method for characterization of carbon materials. The main advantages of confocal microscopy are its non-destructive nature, no special requirements for sample preparation, the depth resolution and the highest image contrast due to stray light suppression. We describe in this paper a new Raman microscopy approach, specially developed 3D scanning confocal Raman microscope Confotec®. The Confotec® confocal system is intended for micro spectroscopic measurements, and it is successfully applied for ultra fast, high resolution, high contrast and informative imaging of various carbon materials.

Authors : Seok Hwan Lee1, Tae Ho Kim2, Seul Bi Lee3, Hyeon Han3, Young Yun Kim13, Sung Cik Mun14, Jeong Eun Won1, Do Youb Kim3, Jae Min Lee3, Sang Hyuk Im5, O Ok Park1*
Affiliations : 1 Department of Chemical and Biomolecular Engineering (BK21 graduate Program), Korea Advanced Institute of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea; 2 Inorganic Material Laboratory, Samsung Advanced Institute of Technology, Suwon, Gyeonggi-do 16678, Republic of Korea; 3 Division of Advanced Materials, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 34114, Republic of Korea;4 Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Ave. S.E., Minneapolis, Minnesota 55455, United States;5 Department of Chemical and Biological Engineering, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul, 02841, Republic of Korea

Resume : Recently graphene quantum dots (GQDs) have been of great interest because of their excellent properties such as excitation wavelength dependent emission, high photo-stability, strong chemical stability, good biocompatibility and excellent charge transport. So far, GQDs have been successfully synthesized by hydrothermal, emulsion templating, and Hummer’s method. However, it is still challenging to synthesize GQDs with high quality graphitic structure and controllable size via solution chemistry because the convention bottom-up process such as hydrothermal and emulsion templating methods produced carbon dots with low crystallinity and the top-down process such as Hummer’s method yielded GQDs with broad size distribution, broad photoluminescence (PL) spectrum and low quantum yield. Here, we synthesized GQDs with high quality crystallinity and uniform controllable size via one-pot single-phase solution chemistry. It is based on dehydration of d-glucose under amine and acetic acid catalytic condition on the basis of taking in-situ 1H NMR spectroscopy during the reaction. Electro-microscopic characterization on GQDs clearly showed that it has hexagonal crystal structure with graphitic crystal plane with under ~1nm thickness and Spectroscopic characterization showed that GQDs exhibited clear excitation dependent PL spectrum with regular interval spectrum shift. Finally, GQDs fabricated into emitting layer on EL device and it has stable deep blue emission with low turn-on voltage.

Authors : Mindaugas Kamarauskas, Mantas Norkus, Vladimir Agafonov, Marius Treideris, Arūnas Šetkus
Affiliations : Center for Physical Sciences and Technology, Sauletekio ave. 3, LT-10257 Vilnius Lithuania

Resume : Silicon solar cells are still the most widely manufactured type of the photovoltaic (PV) devices produced at the costs acceptably low for the practical purposes. In spite of that there are remaining possibilities to further improve the parameters of the devices. A combination of the surface texturing with the formation of a relief following p-n junction can be expected to increase the solar cell area and related PV current without enlargement of the solar module. New emerging technologies presented in this field consist of the new texturing methods for the formation of the “black silicon”(b-Si) on the surface. At present, this method still lacks the economic efficiency due to the use of an expensive texturing technology as, for example, RIE etching and the noble metal catalyst assisted chemical etching. In this work we demonstrate a nickel assisted chemical etching (NACE) for the formation for the “black silicon” compatible with the silicon photovoltaic device technologies. Thin nickel layers deposited by magnetron sputtering we used for the NACE in H2O:H2O2:HF etchant. b-Si layers were investigated by AFM and optical spectrometer. Influence of nickel layer thickness and the etchant composition on the b-Si layer properties were investigated. We demonstrate that using NACE for the formation of the b-Si we can achieve uniform formation on the large silicon area with the average reflectance in the visible range 2.2-2.5% and the lowest reflectance of 0.39-0.45% at 910-930nm.

Authors : Anna Fucikova, Jan Linnros, Ilya Sychugov,
Affiliations : Anna Fucikova, Charles University in Prague, Department of Chemical Physics and Optic, Ke Karlovu 3, 121 16, Prague, Czech Republic; Jan Linnros, Material and Nano Physics Department, ICT School, KTH?Royal Institute of Technology, 16440 Kista, Sweden; Ilya Sychugov,Material and Nano Physics Department, ICT School, KTH?Royal Institute of Technology, 16440 Kista, Sweden;

Resume : Directly synthesised silicon nanocrystals with surface passivation shell are exhibiting extraordinary optical properties (for example ultra narrow linewidth). They are synthesized from hydrogen silsesquioxane-like molecules, which are modified by organic molecules, and subsequently annealed at high temperatures in an almost inert atmosphere. During annealing silicon nanocrystals are formed from hydrogen silsesquioxane and the added organic molecules form a surface passivation shell by bonding to the surface Si atoms of the nanocrystals. The invention is particularly useful for preparation of light emitting fluorophores with a narrow emission band, given that inhomogeneous broadening can be reduced. For example, the silicon nanocrystals prepared from hydrogen silsesquioxane, modified with methyl isobutyl ketone, exhibit a significantly narrower emission peak of individual nanocrystals at room temperature (average linewidth ~25 meV, spectral range from 530-720 nm (1.7-2.3 eV)) compared to silicon nanocrystals embedded in a silicon oxide shell (150 meV), according to single dot spectroscopy. Recently, we have measured an even narrower single silicon nanocrystal linewidth for acetone modified hydrogen silsesquioxane (~ 14 meV).

Authors : Xiao Zhang, Adam Boies, Michael De Volder
Affiliations : Department of Engineering, University of Cambridge

Resume : In order to promote the application of novel nanomaterial assemblies for use as thermal conductors, the measurement of the accurate thermal conductivity values is critical. Novel nanomaterials such as carbon nanotube (CNT) films and fibers, have relative high thermal conductivity, anisotropic thermal properties, low specific heat capacity, low density and large specific surface area. Combined, these properties render conventional transient or steady-state methods inadequate for measurement of thermal conductivity. The frequently-used conventional transient measurements typically involve accurate determination of specific heat capacity and density of sample, which are challenging for nano-materials. Conventional steady-state thermal conductivity measurement methods are hindered by thermal contact resistance which is inevitable in the measure process, and often mixed in the measured thermal conductance value. Additionally, the relatively high anisotropic thermal conductivity, along with the large specific surface area, magnifies the convection and radiation heat loss influence on the measured result. Moreover, due to the low specific heat capacity and thermal conductance of nanomaterials, the heat loss and distribution from attached thermocouples become non-negligible. Here we report a method to measure κ for various nanomaterials, especially CNT films, by means of a low pressure steady-state device. In order to avoid significant contributions from convection heat transfer, a high vacuum chamber is used to mount samples between temperature controlled stages. The precisely temperature profiles of samples were detected using an infrared camera calibrated in accordance with the infrared transparent window. By simultaneous measurement of heat flux through a known reference and the sample material, conductivities of low mass nanomaterials can be determined precisely. Stochastic error propagation modelling is used to determine the accuracy of κ value with a constructive uncertainty in various operating environment. By using this accurate thermal conductivity measurement method, the relationship of thermal conductivity versus temperature and thermal conductivity versus strain of CNT material are discussed. Further analysis of CNT composites is shown to improve conductivities of baseline materials and demonstrate the applicability of the method to measure nanocomposite thermal conductivities for a range of nanomaterial composition and form factors.

Authors : G. M. Klemencic, J. M. Fellows, J. M. Werrell, S. Mandal, S. R. Giblin, R. A. Smith, O. A. Williams
Affiliations : Cardiff University; University of Bristol; Cardiff University; Cardiff University; Cardiff University; University of Birmingham; Cardiff University

Resume : We have studied the low temperature properties of CVD-grown boron doped nanocrystalline diamond films as a function of film thickness in an attempt to better understand the influence of the grain boundaries on the superconductivity. Here I present resistance versus temperature data for a series of films whose grain size is varied by changing the film thickness. For this series, we have extracted the fluctuation conductivity in the vicinity of the superconducting transition and have studied the scaling behaviour with temperature. We have found that there are three distinct scaling regions - 3D intragrain, quasi-0D, and 3D intergrain - in confirmation of the prediction of Lerner, Varlamov and Vinokur [1]. I will describe how this result can be used as a probe of material characteristics in granular superconductors. In particular, I will show how the diffusion constant can be inferred from the location of these dimensional crossovers. [1] Lerner, I. V., A. A. Varlamov, and V. M. Vinokur, Phys. Rev. Lett., 100, 117003 (2008)

Authors : A. Mazurak, J. Jasiński, R. Mroczyński
Affiliations : Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Poland

Resume : For the past several years the structures with silicon nanocrystals (Si-NCs) embedded in dielectric layers have been extensively investigated for a reason of their potential applications in the field of optoelectronics and photonics. Moreover, the metal-insulator-semiconductor (MIS) structures with silicon nanocrystals embedded in the insulator attract significant attention for a reason of their potential applications in memory structures, especially in the non-volatile semiconductor memory (NVSM) devices. The application of high relative permittivity (high-k) materials with the introduction of silicon, or germanium nanocrystals in the gate stack is a possible solution to overcome problems related to scaling issues. In this work, silicon substrates with the resistivity of 1 10 Ωcm were used to fabricate test structures. The hafnium-oxide and silicon dioxide were considered as insulator layers. The Si NCs film of the thickness about 10 nm was spinned off on top of the substrate insulator surface. The formation of NCs layer was followed by the gate insulator deposition. The test MIS structures with colloidal co-doped silicon nanocrystals embedded in the gate insulator layer were investigated by the means of stress-and-sense measurements with different type of stress (voltage, current) and measured response (current, capacitance, voltage). The effect of bias parameters on memory effect is discussed in terms of the charge stored, characteristic voltage shift, and retention time.

Authors : J. López-Vidrier,1 D. Hiller,1 S. Gutsch,1 J. Laube,1 O. Blázquez,2 S. Hernández,2 B. Garrido2 and M. Zacharias1.
Affiliations : 1Laboratory for Nanotechnology, IMTEK, Faculty of Engineering, University of Freiburg, Georges Köhler Allee 103, 79110, Freiburg, Germany. 2MIND-IN2UB, Departament d’Electrònica, Universitat de Barcelona, Martí i Franquès 1, E-08028, Barcelona, Spain.

Resume : Silicon nanocrystals (Si NCs) exhibit band gap energy tunability by modifying their size, which makes them a potential candidate as active material in light-emitting diodes. Amongst the most studied electroluminescence (EL) mechanisms taking place in matrix-embedded Si NC systems, impact excitation and bipolar injection are the most probable ones for electron-hole pair formation within the Si NC. So far, DC electrical excitation of matrix-embedded Si NC systems, which favours inefficient impact excitation, has proved to result in very low EL yield. In contrast, pulsed excitation might more efficiently activate sequential injection of electrons and holes, consequently enhancing EL emission. We explore the EL properties under pulsed excitation of Si NC / SiO2 multilayers embedded in a metal-insulator-semiconductor device structure, with ZnO as transparent conductive oxide on top and Al at the bottom of the structure. EL spectra exhibit contributions from both Si NCs and deep-level defect states within the ZnO band gap. The application of the pulse not only allows enhancing the EL efficiency by about one order of magnitude with respect to DC-excited EL emission, but also tailors its spectral lineshape by quenching the ZnO-related emission at long inversion times, which is attributed to sequential carrier injection through the Si substrate into the multilayers. Finally, the presence of a thin Si3N4 layer was found to act as a hole-injection source that efficiently enhances EL.

Authors : R. Derian, K. Tokár, B. Somogyi, Á. Gali, I. Štich
Affiliations : Center for Comp. Mat. Science, Inst. of Physics, Slovak Acad. of Sciences, 84511 Bratislava, Slovakia; Center for Comp. Mat. Science, Inst. of Physics, Slovak Acad. of Sciences, 84511 Bratislava, Slovakia; Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Budapest, Hungary; Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, Budapest, Hungary; Center for Comp. Mat. Science, Inst. of Physics, Slovak Acad. of Sciences, 84511 Bratislava, Slovakia Inst. of Informatics, Slovak Acad. of Sciences, 845 07 Bratislava, Slovakia Dept. of Natural Sciences, University of Ss. Cyril and Methodius, 917 01 Trnava, Slovakia

Resume : With a rise of co-doped silicon nanocrystals (Si-NC), is desirable to have a relatively cheap computational method, which will have sufficient precision to describe optical properties of either co-doped (doped by Boron and Phosphorus simultaneously) or pristine Si-NC. TD-DFT computational performance is rather satisfying, however, at present, there are several hundreds of DFT functionals on the market, and we show the spread of optical gaps is huge (~ 2 eV). We perform very precise Quantum Monte Carlo (QMC) calculations to benchmark a few DFT functionals and to find the optimal functional allowing accurate prediction of Singlet-Singlet and Singlet-Triplet optical gaps of Si-NC.

Authors : H. J. Yoon, J. Y. Lee and T. H. Yoon
Affiliations : School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST)

Resume : Few-layer graphene (FLG) with large size was prepared via millstone (MS) exfoliation which was utilized for the first time. The millstone was made with two glass plates, top of which was designed to rotate againt stationaly bottom one, generating true shear force for exfoliation. For MS exfoliation, mildly oxidized graphite (MOG) with aryldiazonium salts of sulfonic acid (ADS) grafting was utilized instead of pristine graphite to afford easier exfoliation and better water dispersion of FLG after exfoliation. Exfoliation was monitored via UV-vis Sepectroscpty, while FLG was characterized by TEM and AFM, and good property was demonstraed by sheet resistance measurement.

Authors : S.I. Sidorenko1, Ie.V. Ivashchenko1, G.G.Lobachоva1, V.I. Panarin2, M.Ie. Svavilny, O.M. Hubina1, V.V. Yanchuk1
Affiliations : 1 Metal Physics Department, Igor Sikorsky Kyiv Polytechnic Institute, Ukraine; 2 G.V. Kurdyumov Institute for Metal Physics of the National Academy of Science of Ukraine

Resume : The main feature of biocompatible coatings, used in dental and bone implants is their ability to coalesce with living bone tissue. The drawback of coatings made from pure hydroxyapatite is their low strength. Developed method of hydroxyapatite coating formation, which greatly increases its strength. Strengthening of coatings occurs due to use of carbon nanotubes (CNT), which are connected to the implant surface. Surface with nanotubes using laser processing is sintered with hydroxyappatite, this process allows obtaining such properties as durability and corrosion resistance of the implant. Growing of nanotubes on the surface of single-crystal silicon oxide substrate was carried out using the modified method of CIB (condensation with ionic bombardment) using iron catalyst. Measured diameter of the nanotubes on the surface of a single crystal of SiO2 was ranged into limits 25-15 nm. For сonsolidation of hydroxyapatite on the surface of the plate where the nanotubes were located used such substances as polyethylene glycol (PEG), glycerin and petrolatum. Conducted laser processing of samples with hydroxyapatite and determined that the best substance for adhesion of hydroxyapatite is Vaseline. Conducted laser surface treatment with different laser energy. Established that treatment with beam energy E = 1 J provides the best adhesion of hydroxyapatite layer.

Authors : J. Valenta (a), M. Greben (a), S. Gutsch (b), J. Laube (b), D. Hiller (b), M. Zacharias (b), and S. Dyakov (c)
Affiliations : (a) Faculty of Mathematics & Physics, Charles University, Prague, Czechia (b) Faculty of Engineering, IMTEK, Albert-Ludwigs-University Freiburg, Germany (c) Center for Photonics and Quantum Materials, Skolkovo Institute of Science &Technology, Russia.

Resume : Luminescence quantum yield (QY) is a crucial parameter for light-emitting materials. In case of ensembles of nanocrystals (NCs) in a solid or liquid medium we distinguish external and internal QY (EQY, IQY). EQY is defined as the ratio of total number of emitted to absorbed photons for the whole ensemble, while IQY concerns only the luminescing (bright) subensemble of NCs and is equal to the ratio of radiative and total decay rates. It was shown that many nanomaterials contain significant fraction of “dark” NCs that absorb but not emit photons due to the presence of non-radiative recombination centres (defects) or due to transient switching-off (blinking). EQY is conveniently measured using an integrating (Ulbricht) sphere [1,2] while IQY is usually derived using variation of local density of optical states which affects radiative but not non-radiative lifetime, so enabling to decouple these two components. We study both EQY and IQY of Si NCs using special wedge samples with variable distance between NCs and a high-n substrate. In addition, we adapted all experimental techniques for slow decay time and low saturation threshold of Si NCs and avoided possible artefacts [3]. Combining spectral measurements of EQY, IQY, absorption cross section (ACS) [4] with size distribution of NCs we obtain distribution of dark NCs in an ensemble. While the near-infrared emission (close to the band gap of bulk Si) is almost ideal, both IQY and population of bright NCs decreases toward shorter wavelengths causing vanishing emission below 600 nm. This effect commonly observed in literature is named the Green catastrophe and its physical origin is discussed. [1] J. Valenta, Nanoscience Methods 3 (2014) 11-27 (OA). [2] J. Valenta et al., Appl. Phys. Lett. 105 (2014) 243107. [3] M. Greben and J. Valenta, Rev. Sci. Instr. 87 (2016) 126101. [4] J. Valenta et al. Appl. Phys. Lett. 108 (2016) 023102.

Authors : Jeong Eun Won, Seok Hwan Lee, O Ok Park*
Affiliations : Department of Chemical and Biomolecular Engineering (BK21+ graduate Program), Korea Advanced Institue of Science and Technology, 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea

Resume : Graphene quantum dots (GQDs) have attracted great attention as a new luminescent material due to their unique optical properties, low toxicity, stable photoluminescence, and biocompatibility. In addition, GQDs consist of low cost carbon elements and have low toxicity as a good alternative to the conventional inorganic quantum dots (QDs) which contain toxic metals. Although many synthetic methods of GQDs have been reported, they still have low quantum yield (QY) for optoelectronic applications and have a broad size distribution which needs an extra size selection procedure such as liquid chromatograph and dialysis process. In this work, we obtained the uniform size of nitrogen-doped GQDs (NGQDs) with significantly enhanced QY based on bottom-up method. By doping nitrogen atoms into the GQDs, the relative QY of NGQDs was improved by more than three times compared to the relative QY of reference GQDs. The PL spectrum showed that the NGQDs exhibited an excitation-wavelength-dependent emission mechanism and the emission spectrum was red-shifted by nitrogen doping. Furthermore, NGQDs have a narrow size distribution without the complicated size selection procedure. By obtaining both high uniformity and high QY, NGQDs have a potential for future applications such as light emitting didoes, solar cells, and bio-imaging.

Authors : Sang Woo Lee, Jung Jin Park, Byung Hyun Park, Sung Cik Mun, Yong Tae Park, Kin Liao, Woo Jin Hyun*, and O Ok Park*
Affiliations : Sang Woo Lee; Jung Jin Park; O Ok Park*; Department of Chemical and Biomolecular Engineering (BK21+ Graduate Program) Korea Advanced Institute of Science and Technology (KAIST) 291 Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea Byung Hyun Park; LG Chem. Ltd., 188 Munji-ro, Yuseong-gu, Daejeon, 34122, Republic of Korea Organic analysis PJT, Corporate R&D, Sung Cik Mun; Woo Jin Hyun*; Department of Chemical Engineering and Materials Science University of Minnesota 421 Washington Avenue S.E., Minneapolis, Minnesota 55455, United States. Yong Tae Park; Department of Mechanical Engineering Myongji University 116 Myongji-ro, Cheoin-gu, Youngin, Gyeonggi-do, 17058, Republic of Korea Kin Liao; Department of Mechanical Engineering Khalifa University of Science, Technology & Research Abu Dhabi 127788, United Arab Emirates

Resume : Because of growth of wearable electronics industry, structure modification for sensing material has been widely attempted to improve sensitivity of the strain sensor. Herein, we demonstrate patterned graphene strain sensors, which can monitor small-scale human motions by using facile, scalable and cost-effective patterning method, instead of complex and expensive traditional process such as chemical vapor deposition. Using this patterning method, we can fabricate the patterned polymeric substrates with controlled pattern density, which gives suitable sensitivity of the strain sensor to detect small strain of motions. In addition, graphene layer deposition on the polymeric substrate is achieved by layer-by-layer assembly method, which is scalable and solution-processable technique. Hence, the electrical properties of graphene sensors can be easily tuned by the number of repetition cycles of layer-by-layer assembly, leading to increment of thickness of conducting graphene layers that gives more conductive pathway for electric currents. The thicker coated graphene layer exhibits the lesser sensitivity, however, increased thickness of graphene layer shows better endurance on larger strain loads due to their percolation networks. Compared with non-patterned sensors, the sensors with pattern shows enhanced sensitivity and therefore it can even discern subtle motions, including similar phonations and wrist pulses, with distinguishable distinct peaks in the electric signals.

Authors : Ren-Bao Liu
Affiliations : Department of Physics, The Chinese University of Hong Kong, Hong Kong, China; The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, China; Centre for Quantum Coherence, The Chinese University of Hong Kong, Hong Kong, China

Resume : Nitrogen vacancy (NV) centres in diamond are attractive as room-temperature atomic quantum sensors owing to their superb coherence properties under ambient conditions. However, while they are susceptible to external magnetic fields, the NV centre spin resonances are relatively insensitive to some important parameters such as pressure and temperature. Here we present a scheme of hybrid thermometer composed of NV centres in diamond and a magnetic nanoparticle (MNP). The hybrid nano-sensor has the potential to reach the sensitivity of μK/Hz1/2 under ambient condition thanks to the enhancement due to the critical magnetization of the MNP near the ferromagnetic-paramagnetic transition temperature. We experimentally demonstrated that the temperature susceptibility of the NV center spin resonance can reach 14 MHz/K, a two orders of magnitude enhancement from the value without the MNP. The sensitivity of a CuNi MNP based nano-thermometer under ambient conditions is measured to be 11 mK/Hz1/2. The hybrid diamond thermometers provide a solution of sensitive and stable temperature measurement under ambient conditions and at nanoscale.

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Nanodiamonds for bio-applications and sensing : Nesladek, Cigler
Authors : Anke Krueger,* Viktor Warkentin, Sarah Schweeberg, Stefan Wachtler, Benjamin Kiendl
Affiliations : Institute for Organic Chemistry, Julius-Maximilians-University Wuerzburg, Wuerzburg, Germany

Resume : Surface functionalization of nanoparticles is an essential tool for the control of their chemical, physical and physiological behaviour. Nanodiamond (ND) can easily be modified by using its variety of surface functional moieties.[1] In addition, NDs, having a low to non-existing toxicity, are attractive for biomedical applications.[2] However, when ND are exposed to bio-fluids, such as cell culture serum, proteins adsorb on the surface of the particles and form in situ a “protein corona”. This corona masks the desired functionalities on the surface and changes the interaction with the surrounding fluid. Both, the colloidal stability and the physiological properties are not controllable anymore.[3] Here, we report on different strategies to control the colloidal stability of nanodiamond in physiological media using surface functionalization as well as colloid chemistry techniques such as electrosteric stabilization. Furthermore, examples for the application of those functionalized nanodiamond conjugates and composites will be presented including the use in regenerative medicine, sensing and drug delivery. The funding of this research by the Volkswagen Foundation (Az.: 88 393) is gratefully acknowledged. [1] A. Krueger, D. Lang, Adv. Funct. Mater. 2012, 22, 890. [2] A. Krueger, Chem. Eur. J. 2008, 14, 1382. [3] W. C. W. Chan, C. D. Walkey, J. Am. Chem. Soc. 2012, 134, 2139.

Authors : Marie Krečmarová, Thijs Vandenryt, Emilie Bourgeois, Michal Gulka, Josef Souček, Ronald Thoelen, Vincent Mortet and Miloš Nesládek
Affiliations : Institute for Materials Research, Material Physics Division University of Hasselt, Wetenschapspark 1, B 3590 Diepenbeek, Belgium; IMOMEC division of IMEC, Wetenschapspark 1, B 3590 Diepenbeek, Belgium; Czech Technical University in Prague, Faculty of Biomedical Engineering, Nám. Sítná 3105, 272 01 Kladno, Czech Republic; Institute of Physics, Academy of Sciences Czech Republic v.v.i, Na Slovance 1999/2, 182 21 Praha 8, Czech Republic

Resume : We present a novel concept of biomolecular sensors based on operation of quantum colour centres in diamond integrated to a microfluidic biosensor. The developed device is based on a combination of NV centre optical readout combined with an electrochemical device. By this way the device can lock on an electrochemical potential specific for particular reactions and to use the NV centre charge state for detection of specific chemical reaction products. The diamond device consists of highly boron doped diamond electrode capped with a thin (10 nm) NV centres containing layer. The device is then covered by polydimethylsiloxane flow cell and transparent indium tin oxide coated glass slide. Switching of the NV-/NV0 centre population is detected by photoluminescence (PL). We set first the charge state occupation of NV centre by applying a bias voltage between source and gate electrode. The charge state of NV centres then react to electrochemical potential of the environment. To demonstrate the label free optical detection the diamond surface is covered with a monolayer of strongly cationic charged polymer polyethylenimine (PEI) that modify charge state of near surface NV centres to NV0 or NV non-PL state. Immobilization of negatively charged DNA molecules on the sensor surface changes NV centres charge states to preferably NV- and the PL is detected by confocal microscopy. The biochemical reactions in the microfluidic channel are controlled by electrochemical impedance spectroscopy.

Authors : Michal Gulka (1 2 3), Bela Varga (4 5), Hamideh Salehi (6), Elodie Middendorp (6), Thierry Cloitre (4), Frederic J.G. Cuisinier (6), Petr Cígler (7), Milo? Nesládek (1 3), Csilla Gergely (4)
Affiliations : (1) CTU in Prague, Faculty of Biomedical Engineering, Sítná sq. 3105, 272 01, Kladno, Czech Republic; (2) Institute of Physics, AS CR, v.v.i., Na Slovance 5, 185 00, Prague 8, Czech Republic; (3) IMOMEC division, IMEC, Institute for Materials Research, University Hasselt, Diepenbeek, Belgium; (4) Laboratoire Charles Coulomb (L2C), UMR 5221 CNRS-Université de Montpellier, Montpellier, F-France; (5) Institute of Biophysics, Biological Research Centre, 6726 Temesvári krt. 62, Szeged, Hungary; (6) Bio-engineering Nanoscience Laboratory, EA 4203 Université de Montpellier, Montpellier, F-France; (7) Institute of Organic Chemistry and Biochemistry AS CR, v.v.i. Flemingovo nam. 2, 166 10 Prague 6, Czech Republic

Resume : Luminescent nanodiamonds (ND) are attractive tools for nanoscale biologic cellular imaging allowing both photoluminescence (PL) and magnetic resonance imaging [1]. Recent technological developments enable to fabricate bright NDs with high content of nitrogen-vacancy (NV) centres [2] that are anticipated to serve as a cell probes. In this work we present novel method of NDs detection in cellular environment. We demonstrate simultaneous visualization of NDs and of the non-labeled nucleus of living cells based on Raman and PL detection as a new tool for the localization of internalized nanoparticles. To this end, NDs of size ranging from ultra-small particles ~ 5 nm to 60 nm were used, prepared from Ib synthetic diamond. Particles were electron irradiated, annealed and plasma oxidized to create NV centers [3]. Cells used for this experiment were breast cancer (MCF7). Successful internalization of NDs and their localization in cells is determined using a TEM. Whilst standard Raman imaging methods of NDs make use of the sp3 diamond Raman signal, which limits their use to 100 nm size particles or bigger [4], here we employ Raman imaging in a novel way to detect small near-IR cellular probe. Specifically, the Raman signal from the cellular environment is spectrally processed using K-mean cluster analysis of 2D map. By mapping the intensity of the lipid contribution to the C-H Raman peak, we are able to visualize the cell nucleus clearly on non-fixed cells. This information is combined with PL detection of small (~ 5 nm) particles to visualize the position of NDs and distinguish between the internalized and non-internalized particles. Merging of these two images obtained simultaneously allows to obtain a spatially precise ND position and to determine its closer environment. [1] L. Moore, M. Nesladek et al., Nanoscale (2014) [2] J. Havlik, M. Gulka, M. Nesladek et al., Nanoscale (2013) [3] J. Stursa, M. Gulka, M. Nesladek et al., Carbon (2016) [4] C.-Y. Cheng et al., Applied Physics Letter (2007) ACKNOWLEDGMENTS: Czech Science Foundation project GA16-16336S

Authors : Ting Zhang, Gangqin Liu, Chufeng Liu, Winghang Leung, Xi Feng, Renbao Liu, Quan Li
Affiliations : Department of Physics, The Chinese University of Hong Kong

Resume : The excellent bio-compatibility, high photo-stability, and the long spin coherence time at room temperature make Nitrogen-vacancy (NV) in diamond a promising sensor for biological applications. However, its sensitivity to parameters such as temperature is low when considering the possibly very small temperature variation in biological systems, and it does not respond to many important biochemical parameters including pH and non-magnetic biomolecules. Here we propose a scheme of magnetic nanoparticle/nanodiamond based hybrid structure that can potentially enable the measurement of various biochemical parameters using NV based sensing. In this talk, we show the proof-of-the-concept demonstration of temperature sensing using such a hybrid sensor. The same principle can be well applied to detection of changes in other biochemical parameters using sensors of the same principle.

Carbon and silicon for bio and sensing : Valenta, Krueger
Authors : Petr Cigler
Affiliations : Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Prague

Resume : Diamond nanocrystals with nitrogen-vacancy (NV) crystal defects are near-infrared fluorescent emitters which have been utilized, for example, as single-photon sources or as fluorescent biomarkers of extreme photostability and low toxicity. Importantly, spin states of NV center show unique sensitivity to magnetic and electric fields, enabling for construction of probes based on quantum mechanical interactions. For preparation and selective operation of such probes in biological environment a functional chemical interface is a key component. Combination of synthetic chemistry with rational molecular design leading to novel sensing interfaces readable with NV centers will be discussed. Modification of nanodiamond using polymers, attachment of responsive sensing structures for detection of charge status of polymers, DNA transfection, pH, redox potential, and physico-chemical properties of these constructs will be explained in detail.

Authors : Tereza Belinova1,2, Lucie Vrabcova1,2, Anna Fucikova3, Jan Valenta3, Hiroshi Sugimoto4 , Minoru Fujii4, Marie Hubalek Kalbacova1
Affiliations : 1 Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic 2 Department of the Cell Biology, Faculty of Science, Charles University, Prague, Czech Republic 3 Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Prague, Czech Republic 4 Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe, Japan

Resume : Silicon is a material with remarkable properties as biocompatibility and biodegradability, which make it an interesting platform for biomedical studies. Silicon nanoparticles (quantum dots) co-doped with boron and phosphorus, with diameter around 4 nanometres evincing fluorescence and dispersability in aqueous solutions were studied in respect to their impact on different human cells. Firstly, it was necessary to determine their level of cytotoxicity in different types of human cells and secondly their interaction with these cells. Osteoblastic cell line and cell line of immune cells, which can be studied in two stages – as monocytes (suspension cells circulating freely in blood) and as macrophages (adherent cells localized in specific tissues) were used. Exposing cells to rising concentrations of quantum dots under different conditions and consecutive evaluation of their cytotoxicity brought an overview on cell specific reaction to their identical doses. Further, colocalization studies of nanoparticle signal and cell specific structures (organelles) of endocytic pathway were performed using fluorescence confocal microscopy and other techniques at different time points. Obtained results show significant importance of cultivation conditions (e.g. formation of protein corona on nanoparticles originating from media supplement) as well as significant impact of cell type (increased sensitivity of monocytes to studied quantum dots in comparison to other cell types). These results thus provide an insight on future directions of related research.

Authors : Jacobo Hernandez Montelongo, Lorena Oria, ana Belen Cárdenas, Gonzalo Recio Sánchez
Affiliations : Departamento de Ciencias Naturales y Exactas, Centro Universitario de los Valles, Universidad de Guadalajara, Ameca, Jalisco, Mexico; Núcleo de bioproductos y materiales avanzados. facultad de ingeniería, Universidad católica de Temuco; Núcleo de bioproductos y materiales avanzados. facultad de ingeniería, Universidad católica de Temuco; Núcleo de bioproductos y materiales avanzados. facultad de ingeniería, Universidad católica de Temuco

Resume : Nanostructure porous silicon (NanoPSi) is a nanostructured biomaterial which has received considerable attention in biomedical applications due to its biocompatibility, biodegradability, high surface area and the ease to modify its surface chemistry. In the present work, nanoPSi composite microparticles were evaluated as potential drug delivery system. NanoPSi layers were formed by electrochemical etching of silicon wafers in hydroflruoridric acid solutions. This fabrication process allows modifying the main properties of nanoPSi layers including the porosity, average pore size and pore shape, by simply controlling the main parameters in the fabrication process such as the applied current density and electrolyte composition. NanoPSi micro-nano particles were prepared from the removal and facture by ultrasound sonication of nanoPSi layers. Composites were obtained from oxidized nanoPSi (OPSi) microparticles cascade processed with chitosan (CHI) and β-cyclodextrin (β-CD) biopolymers. OPSi, CHI and β-CD composites were evaluated as drug delivery system using florfenicol as model drug, due to the economical and sanitary importance in salmon industry. Drug loaded and release kinetic text were performed in different medias: distilled water, simulated seawater and simulated physiological media. Initial data show that β-CD composites allowed a mayor control in the drug time release kinetic compared with OPSi microparticles and CHI composite.

Authors : Cao, A.(1) ,Zhu, W.(2), Shang, J.(3,4) , Shan, M.(1), Paltrinieri, L.(1,5), Evers, W.(1), Chu, L.(1), Poltorak, L.(1), Klootwijk, J.H.(5), Gascon, J.(1), Huskens, J.(2), Sudhölter, E.J.R.(1), de Smet, L.C.P.M.(1,7)
Affiliations : 1 - Delft University of Technology, Department of Chemical Engineering, Delft, The Netherlands 2 - University of Twente, MESA+, Institute for Nanotechnology, Enschede, The Netherlands 3- City University of Hong Kong, School of Energy and Environment, Kowloon, Hong Kong SAR 4 - University of Melbourne, Department of Chemical and Biomolecular Engineering, Parkville, Australia 5 - Wetsus – European centre of excellence for sustainable water technology, Leeuwarden, The Netherlands 6 - Philips Research Laboratories, Eindhoven, The Netherlands 7 - Wageningen University & Research, Laboratory of Organic Chemistry, Wageningen, The Netherlands

Resume : Over the past ~15 years, silicon nanowire(SiNW)-based sensor devices have gained increasing interest due to their reliable and reproducible electrical properties, the possibility of down-scaling and integration for the simultaneous detection of multiple parameters. Various types of affinity layers have been deposited onto or bound to the surfaces of the silicon nanowires, aiming to introduce selectivity towards a specific target analyte, including ions and bio(molecules). Recent advances in the design and synthesis of molecular architectures have resulted in the availability of a large variety of porous materials that are interesting candidate building blocks for chemical sensing purposes. In this work, we present several surface modification strategies to chemically bind porous materials to SiNW-based sensors. The functionalized devices were subsequently studied in the depletion regime under different environmental conditions, probing selectivity. In the first case (1) we prepared metal−organic polyhedra (MOPs) from organic ligands and an unsaturated metal site. The MOPs were grafted onto pyridyl-coated SiNW-based sensors at room temperature. Based on a unique confinement effect and host-enhanced charge-transfer interactions the MOP cages enabled the electrical detection and discrimination of structurally related explosives, including 2,4,6-trinitrotoluene (TNT). In a second study (2), we prepared porous organic frameworks directly onto amine-terminated SiNW-based sensor using two organic building blocks that were polycondensated at 453 K. The resulting covalently attached porous affinity layers increased the device response to changes in humidity. Moreover, advanced sensing properties of methanol vapors were realized via the post-synthesis functionalization of the POF-SiNW hybrid by the in-situ formation of platinum nanoparticles (Pt NPs). The surface modification strategies, including surface characterization, and the proposed selectivity mechanisms will be discussed in detail. Our work shows the potential of porous architectures as receptors onto electrode structures. Moreover, the presented NP/MOP system may also find utilization in the fields of gas separations and catalysis. References 1. Enhanced Vapor Sensing using Silicon Nanowire Devices Coated with Pt Nanoparticle Functionalized Porous Organic Frameworks, Cao, Shan, Paltrinieri, Evers, Chu, Poltorak, Klootwijk, Gascon, Sudhölter, de Smet – manuscript under review. 2. Metal-Organic Polyhedra-Coated Si Nanowires for Sensitive Detection of Trace Explosives, Cao, Zhu, Shang, Klootwijk, Sudhölter, Huskens, de Smet, Nano Lett. 2017, 17, 1-7.

Si/Ge and SiC structures : Fujii, Delerue
Authors : Naoki Fukata
Affiliations : National Institute for Materials Science (NIMS)

Resume : Silicon and germanium nanowires (SiNWs and GeNWs) are anticipated for the realization of next-generation metal-oxide-semiconductor field-effect transistors. Impurity doping is one of the key techniques for the NWs devices [1], while the retardation of carrier mobility due to impurity scattering has to be taken into account. Core-shell NWs composed of Si and Ge are key structures for realizing high mobility transistor channels, since core-shell structures separate the carrier transport region from the impurity doped region, resulting in the suppression of impurity scattering [2,3]. Si/Ge and Ge/Si core-shell NWs were rationally grown on a Si substrate by CVD. The TEM and EDX images of i-Ge/p-Si (i: intrinsic, p: p-type) core-shell NWs clearly show the formation of i-Ge/p-Si core-shell NWs and clear lattice fringes in the shell regions. XRD measurements were performed to evaluate the stress induced in the radial hetero core-shell structures. The results clearly revealed stress in the core and shell regions and characterized the compressive and tensile stress present. The average lattice constant of the Ge core is smaller than bulk Ge, showing that the compressive stress is applied by the radial growth of p-Si shell. The average lattice constant of the p-Si shell is greater than that for bulk Si. This is due to the tensile stress from the Ge core. To confirm the selective B-doping in the shell region, we performed Raman measurements. The electrical activity of B atoms can be clarified by the Fano effect [2], which is due to coupling between discrete optical phonons and the continuum of interband electron excitations in degenerately doped p-type Si. The Si optical phonon peaks observed for i-Ge/p-Si NWs shows an asymmetric broadening toward higher wavenumber, whereas no asymmetric broadening was observed for the i-Si shell. This asymmetric broadening is due to the Fano effect, showing that B atoms are electrical activated in the Si shell, resulting in the formation of p-Si shell. Precise analysis using Raman spectroscopy were further performed. We finally got a conclusive evidence of hole gas accumulation in Ge/Si core-shell NWs [3]. References [1] N. Fukata, Adv. Mater 21, 2829-2832 (2009). [2] N. Fukata et al., ACS NANO 6, 8887-8895 (2012). [3] N. Fukata et al., ACS NANO 9, 12182-12188 (2015).

Authors : Ivan Marri, Gianluca Tiribò, Oliva Pulci, Stefano Ossicini
Affiliations : CNR-Nano Istituto Nanoscienze Via Campi 213 A 41125 Modena Italy, Dipartimento di Fisica Università di Roma II “Tor Vergata” Via della Ricerca Scientifica 1 00133 Roma Italy, Dipartimento di Fisica Università di Roma II “Tor Vergata” Via della Ricerca Scientifica 1 00133 Roma Italy, Dipartimento di Scienze e Metodi dell’Ingegneria Università di Modena e Reggio Emilia via Amendola 2 Pad. Morselli I-42100 Reggio Emilia Italy

Resume : The optoelectronic properties arising from the combination of group IV compounds like Si and Ge indicate that their heterostructures are very promising materials for several technological applications. In particular in recent years wide attention has been devoted to Si/Ge and Ge/Si core-shell nanocrystals. These nanostructures present unique electronic and optical properties that are directly linked to their size, structure, composition and organization. Here we will present our recent ab-initio results concerning their structural and optoelectronic properties. In particular we will show how the localization of the electrons and holes, the charge separation, the band-offset and consequently the optical properties are related to the size and the core-shell (Si/Ge or Ge/Si) structure of these compounds.

Authors : David Barba, Chao Wang, Adrien Nelis, Guy Terwagne, Yiqian Wang, Federico Rosei
Affiliations : INRS: Énergie, Matériaux et Télécommunications, Varennes J3X 1S2, Canada LARN: Université de Namur, B-5000 Namur, Belgium Qingdao University, Qingdao 266071, People’s Republic of China

Resume : The operability and durability of erbium and germanium doped fused silica components in harsh environments are limited by thermal diffusion, responsible for structural changes that induce irreversible material degradation and failure. An alternative solution for improving both the thermal and the radiation resistance of these compounds consists of synthesizing Si-, Ge- and Er-based nanoclusters. This technique enables to control atom diffusion, using chemical trapping effects induced by silicon dangling bonds and the pinning of nanoaggregates by silicon nanoparticles during high temperature annealing. Our experimental approach and methodology combine the fabrication of advanced materials by the use of single or multiple ion implantations, with subsequent advanced characterizations by Raman/photoluminescence spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and nuclear analysis. Our work shed light on the nucleation processes of group-IV nanocrystallites, as well as on the formation of nanocavities in Ge-based materials. The nanoclustering of mixed Si/Er and Si/Ge materials is also found to extend the lifetime of near infrared Er light sources exposed to cosmic radiations, and prevent Ge desorption, more than several hundred degrees above heating conditions where drastic outgassing effects occur. High resolution imaging supported by Monte-Carlo simulations and Rutherford Backscattering Spectroscopy measurements shows how the size, the homogeneity, the depth-distribution, as well as the composition and the crystallinity of the formed nanoclusters can be set as a function of the fabrication parameters, in order to design components with specific properties and superior resistance.

Authors : P.I.Gaiduk, A.Nylandsted Larsen
Affiliations : Department of Physical Electronics and Nanotechnology, Belarusian State University, Minsk, Belarus; Department of Physics and Astronomy/iNANO, Aarhus University, Denmark

Resume : The formation of new Si-based materials with enhanced light absorption is of great importance for the development of high efficient photovoltaic devices. A possible approach for enhanced light absorption is connected to excitation of localized surface plasmons after interaction of photons with nano-cavities, metallic nano-shells and nano-particles. The plasmonic excitations are then transferred to a semiconductor to generate electron-hole pairs. The concept of the study is based on self-assembled formation of voids in strained Si/SiGe heterostructures. We will briefly review the effects of strain-driven nano-void formation in Si/SiGeSn layers, gettering and segregation of impurities and formation of buried nano-shells and nano-dots of Ge, Sn and Au in Si layers located nearby to p-n-junction. Structural transformation in the Si/SiGe layers during self-assembling of nano-voids, optical and electronic properties of the layers, and resulting effects of nanostructures on the spectral dependence of the photocurrent in the Si/SiGe structures will be reported. It will be discussed in the talk that metallic nano-shells possess tuneable optical resonances. By varying the relative core and shell thicknesses, the absorption and scattering properties of metallic nano-shells can be varied in a broad range. Finally, special attention will be devoted to possible plasmonic structures for enhancement of the efficiency of Si-based photovoltaic devices.

Authors : David Beke, Gábor Bortel, Katalin Kamarás, Adam Gali
Affiliations : Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary

Resume : Silicon carbide (SiC) is a stable, chemically inert wide band gap semiconductor, and a promising material for bioimaging, targeted drug delivery, nanosensing, optoelectronics and for heterogeneous photocatalysis as well, especially in nano size. Biocompatibility of bulk SiC and SiC nanoparticles (NPs) has been proven by several research teams and the aqueous solutions of SiC NPs are exceedingly promising candidates to realize bioinert nonperturbative fluorescent nanoparticles for in vivo bioimaging. However, most of the synthesized luminescent NPs have environment sensitive, size independent violet-blue emission where the typical size of efficiently luminescent SiC NPs is around 3 nm. A redshift in the emission would be advisable for in vivo bioimaging applications that might be achieved by tight control of the size of SiC NPs. We show here that size distribution of SiC NPs can be tuned via the concentration variation of hexagonal inclusions in the precursor bulk SiC matrix used for stain etching. By proper engineering of hexagonal inclusions into the cubic SiC powder, 4-6 nm SiC NPs can be prepared from this cubic SiC powder by stain etching. These new SiC NPs exhibit redshift in the emission that can be explained by quantum confinement effect on the electronic states participating in the emission process. The redshifted luminescence and the significantly quantum yield of these new larger SiC NPs make them very promising biomarkers.

Doping and codoping Si nanostructures : Valenta, Marri
Authors : Christophe Delerue
Affiliations : IEMN-CNRS, Lille, France

Resume : Si nanocrystals codoped with P (donor) and B (acceptor) impurities exhibit very interesting optical properties, including efficient photoluminescence (PL) in a wide energy range (0.85-1.8 eV) that overcomes the bulk Si bandgap limitation [1]. Furthermore, the codoped nanocrystals are very stable, which is promising for applications. In this talk, I review the theoretical investigations on the electronic structure of (co)doped Si nanocrystals. The theory of Si nanocrystals doped with a single P impurity is compared with the results of Electron Paramagnetic Resonance experiments. Next I present recent results on Si nanocrystals doped with the same number of donor and acceptors. The variation of the gap versus nanocrystal size and impurity concentration is studied in a systematic manner. The experimental trends are discussed in comparison with the theory. I analyze the intrinsic effects of disorder on the linewidth of the PL spectra, as well as the influence of the dopants on the zero-phonon radiative lifetime. [1] H. Sugimoto et al, J. Phys. Chem. C 117, 11850 (2013).

Authors : Bálint Somogyi, Adam Gali
Affiliations : Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary; Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Hungarian Academy of Sciences, P.O. Box 49, H-1525 Budapest, Hungary Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki ú t 8, H-1111 Budapest, Hungary

Resume : Couple-nanometer sized silicon nanoparticles (Si NPs) are promising for novel optoelectronic and biological applications as these SiC NPs exhibit relatively strong fluorescence. These Si NPs can be co-doped by boron and phosphorus at very high concentration. The resulted highly co-doped Si NPs show a red-shift in the emission upon illumination. Furthermore, co-doping drastically slows down the oxidation of nanoparticles. Despite the favourable properties of co-doped Si NPs, very little is known about their structure because conventional experimental techniques such as photoluminescence spectroscopy or Raman/infrared spectroscopy offers only limited insight on their structure at the atomic scale. We employ ab initio atomistic simulational methods based on density functional theory (DFT) to study the structural, electronic and optical properties of co-doped Si NPs. We study 1.5-2.0 nm sized NPs with different surface terminations and various dopant concentrations. The optical excitation is calculated by time-dependent DFT, and the emission spectra and resonant Raman spectra are calculated within the Franck-Condon approximation. We focus on the distribution of dopant atoms inside the nanocrystal and study the properties of the NP surface extensively where the presence of oxygen atoms makes the comprehension of the structure more challenging. We show that boron can form such complexes with oxygen at the interface of the core Si and its oxidized layer that lead to non-radiative relaxation of the photoexcited electron. We also provide a detailed analysis on the distribution of phosphorus and boron dopants inside Si NPs, and how the relative position of dopants influence the optical properties of Si NPs.

Authors : Hiroshi Sugimoto, Yusuke Ozaki, Minoru Fujii
Affiliations : Department of Electrical and Electronic Engineering, Graduate School of Engineering, Kobe University, Rokkodai, Nada, Kobe 657-8501, Japan

Resume : Si nanocrystals (NCs) have been a subject of intensive research for many years as biocompatible nano-light-emitters. However, for light emitting and detecting applications, there still remains an essential issues which is the small absorption cross-section (ACS) of Si NCs in the visible range due to the indirect band gap nature. An effective way to overcome this issue is utilizing the surface plasmon resonance excitation of noble metal nanostructures. Although the enhanced emission rate and ACS by the plasmon resonance have been reported in the past decade, the enhancement factors are limited (less than 10) mainly due to the losses of metals that cause nonradiative quenching of nearby emitters. In this work, we propose the dielectric scattering media for enhanced light ACS and emission intensity of Si NCs without suffering from the material losses. We prepare the thin films of polymer using water-dispersible Si NCs and by controlling the concentration of precursors, a highly-scattering xerogel film is produced. The films have submicron pores and exhibit cavity resonances in the visible range, which results in the enhancement of effective ACS of Si NCs by 20 times at 500-600 nm due to the multiple scattering effect. We also show that photoluminescence (PL) of Si NCs is enhanced at most 40-folds and discuss the enhancement mechanism from time-resolved and micro-PL analyses. [1] H. Sugimoto, et al., ACS Appl. Mater. Int. (2017) DOI: 10.1021/acsami.7b04292

Authors : Daniel Hiller
Affiliations : Laboratory for Nanotechnology, Dept. of Microsystems Engineering (IMTEK), University of Freiburg, Germany

Resume : Impurity doping of Si with e.g. P or B is the backbone of CMOS electronics since it allows to determine the conductivity type and the resistivity. However, at the bottom end of the nanoscale, as approached by future technology nodes, conventional impurity doping is a non-trivial task. Some problems are related to technological aspects (diffusion, “dopant fingerprint”), others to fundamental physical obstacles (quantum- and dielectric confinement). Using ultra-small Si nanovolumes of ≤5 nm in diameter as a model system, we demonstrate that P-dopants have twice the substitutional formation energy and up to 5-times the ionization energy compared to P in bulk-Si [1]. Hence, there are diminutive free carrier densities from thermal ionization at room temperature. For boron, the situation is further complicated by the lower solubility of B in Si. By means of atom probe tomography (APT) we measure a much smaller amount of B-incorporating nanocrystals compared to phosphorus. Electrical measurements do not reveal any B-doping-related effects, whereas B-induced defects apparently cause a photoluminescence quenching [2]. In search of alternative doping methods, a potential approach originating from density functional theory (DFT) calculations is presented, which employs an acceptor state in Al-doped SiO2 adjacent to Si to induce p-type behavior in analogy to conventional III-V semiconductor modulation doping [3]. [1] D. Hiller et al., Sci. Rep. 7, 863 (2017) [2] D. Hiller et al., under review [3] D. König et al., Sci. Rep. 7, 46703 (2017)

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Plasmonics and electric signals from carbon structures : Nesladek, Li
Authors : Shuo Li, Robert J. Hamers
Affiliations : University of Wisconsin-Madison, USA

Resume : The integration of diamond with plasmonic nanoparticles provides a pathway to alter the optical properties of diamond in novel ways. One challenge in synthesizing plasmonic diamond films is that at the the growth temperatures typically used, most metals with suitable optical properties are molten, leading to rapid coarsening and formation of large puddles of metal. We have developed approaches to formation of diamond films on silicon and on quartz with embedded nanoparticles <50 nm in diameter that exhibit clear plasmonic resonances in the visible and near-UV regions. Optical characterization of diamond films grown on quartz show plasmonic resonances in both transmission and reflection mode. Tuning the size of the nanoparticles controllably alters the frequencies of the plasmonic resonances in the expected manner and consistent with numerical modeling of the resulting structures.

Authors : B. Rezek(1)(2), D. Miliaieva(1)(2), P. Matunova(1)(2), V. Jirasek(1), S. Stehlik(1), P. ¦tenclová(1), J. Čermák(1)
Affiliations : (1) Institute of Physics CAS, Prague, Czech Republic; (2) Faculty of Electrical Engineering, Czech Technical University, Prague, Czech Republic.

Resume : Low-cost, stable, and efficient renewable energy is nowadays increasing in importance. Diamond-based inorganic-organic hybrid systems may have an immense, yet still mostly unexplored potential in photovoltaic solar cells. That was suggested for instance by previously measured transfer of photo-generated charge between bulk diamond and polypyrrole (PPy) or other organic molecules. In this work, we characterize opto-electronic interactions of nanodiamonds (NDs) having various surface chemistry including physisorbed or chemisorbed PPy as organic dye. By using Kelvin probe microscopic and macroscopic measurements we show that even pristine NDs can generate photovoltage, in the range of 5-50 mV, depending on their surface chemistry (characterized by FTIR, Raman) and substrate (i.e. bottom electrode). The photovoltage is further enhanced by merging nanodiamonds with PPy. The hybrid system also exhibits enhanced absorption coefficient. The experimental data are corroborated by DFT calculations showing HOMO-LUMO separation in PPy-NDs hybrid structures. Preliminary tests of nanodiamonds in complete organic solar cells show that the cell fabrication technology must still be optimized though.

Authors : A.I. Manilov 1, A.V. Kozinetz 1, I.V. Gavrylchenko 1, Yu.S. Milovanov 1, T.M. Mukhamedzhanov 1, S.A. Alekseev 1, M. AlAraimi 2, A. Rozhin 2, S.V. Litvinenko 1, V.A. Skryshevsky 1
Affiliations : 1 Corporation Science Park Taras Shevchenko University of Kyiv, Volodymyrska Str., 60, 01033 Kyiv, Ukraine; 2 Aston University, Aston Triangle, B4 7ET Birmingham, UK

Resume : The principle of photoelectric conversion in deep p-n junction is applied to control the presence of carbon nanotubes (SWNT) with adsorbed surfactant (SDBS) in aqueous solution. Surface distribution of photocurrent through the silicon wafer with deep p-n junction and different polymer coatings (1-decene, HEMA) is measured. Interaction of the sensor layer with deionized water and aqueous solutions of SDBS and SWNT results in growth of the photocurrent in 3-4 times. The shift of photocurrent dependence on voltage applied between the aqueous solution and the silicon wafer is registered. This shift depends on presence of SDBS molecules and carbon nanotubes in the water. Changes in effective recombination rate corresponding to surface photocurrent distribution can be caused by modification of surface band bending and capture cross-sections of recombination centers at the polymer-silicon interface. The obtained effect can be used as the instrument for detection of carbon nanotubes with adsorbed surfactant in aqueous solution.

Authors : L. Ondič
Affiliations : Institute of Physics, ASCR, v.v.i., Czech Republic

Resume : Optically active color centers in diamond are promising candidates for applications in quantum photonics or biology. In our work, we have tailored dimensions of diamond photonic crystal (PhC) slabs in order to manipulate and enhance the extraction of light emitted by one type of the color centers, the silicon vacancy (SiV) centers. SiV centers possess narrow room-temperature photoluminescence (PL) peak at around 738 nm and thus dimensions of the PhC have to be tuned precisely in order to spectrally overlap the PL with photonic modes of the structure. We have developed relatively simple approach to achieve this spectral overlap, which is based on bottom-up growth of diamond layers on pre-patterned silica substrates. We will show that more than 14-fold enhancement of light extraction from SiV centers can be achieved using this approach. Computer simulation confirmed that the extraction enhancement originates from the efficient light-matter interaction between light emitted from the SiV centers and the PhC slab.

Thermal, mechanical and other dynamics in group-IV nanostructures : Fujii, Ondic
Authors : Ioan Andricioaei
Affiliations : School of Physical Sciences University of California, Irvine

Resume : The interaction of single-walled carbon nanotubes (SWNTs) with DNA is crucial for several nanotechnology applications, including SWNT:DNA nanoscale devices or nanosized building blocks for use in nanosize switches and nanoscale wiring. In biotechnological applications, modulating the DNA:SWNT interaction is important for SWNT purification, DNA recognition, and ultrafast DNA sequencing, and drug delivery. I will present a study of the the conformational equilibrium and the dynamics between B-to-A forms of double-stranded DNA adsorbed onto single-walled carbon nanotubes (SWNT) using free energy profile calculations based on all-atom molecular dynamics simulations. The potential of mean force of the B-to-A transition of ds-DNA in the presence of an uncharged (10,0) carbon nanotube for two dodecamers with poly-AT or poly-GC sequences is calculated as a function of a root-mean-square-distance metric quantifying the B-to-A transition. The calculations reveal that in the presence of a SWNT DNA favors B-form DNA significantly in both poly-GC and poly-AT sequences. Furthermore, the poly-AT DNA:SWNT complex shows a higher energy penalty for adopting an A-like conformation than poly-GC DNA:SWNT by several kcal/mol. The presence of a SWNT on either poly-AT or poly-GC DNA affects the free energy of the transition such that the B form is favored by as much as 10 kcal/mol. The results have consequence for understanding thermal and conduction properties of composites of nanotubes and DNA measured in biotechnology applications.

Authors : K. Voitenko, D. Andrusenko, M. Isaiev, S. Gryn, S. Alekseev, A. Kuzmich, B. Zousman, A. Gershovich, O. Levinson, R. Burbelo, and V. Lysenko
Affiliations : Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska str., 01601 Kyiv, Ukraine; Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska str., 01601 Kyiv, Ukraine; Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska str., 01601 Kyiv, Ukraine; Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska str., 01601 Kyiv, Ukraine; Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska str., 01601 Kyiv, Ukraine; Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska str., 01601 Kyiv, Ukraine; Ray Techniques Ltd, Hebrew University of Jerusalem, P.O.B. 39162, Israel; Ray Techniques Ltd, Hebrew University of Jerusalem, P.O.B. 39162, Israel; Ray Techniques Ltd, Hebrew University of Jerusalem, P.O.B. 39162, Israel; Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska str., 01601 Kyiv, Ukraine; Institut des Nanotechnologies de Lyon, CNRS, Université de Lyon, 7 Avenue Jean Capelle, Baîtiment Blaise Pascal, Villeurbanne, France

Resume : Thermal transport through solid-liquid interfaces plays an important role in many chemical and biological processes. Therefore, better understanding of heat transfer through such kind of interfaces will render much more efficient their numerous multidisciplinary applications. Our current contribution reports on thermal conductivity study of carbon-based nanofluids by photoacoustic technique. These biocompatible nanomaterials are successfully applied in biomedical imaging, tissue engineering, drug delivery systems and theranostics. In our research work, photoacoustic technique with piezoelectric detection has been used as an efficient tool for the study of thermal transport properties of the carbon-based nanofluids. Amplitude- and phase-frequency characteristics of the photoacoustic responses from the nanofluids have been measured. Concentration dependence of thermal conductivity of the nanofluid has been studied in details. Additionally, the heat transfer across nanoparticle/fluid interface has been simulated by molecular dynamics. Influence of nanostructuration of solid/liquid interface on some thermal parameters of the nanofluids will be also reported. This research work has been carried out in frames of CARTHER project (proposal #690945) of Marie Skłodowska-Curie Research and Innovation Staff Exchange program.

Authors : Mykola Isaiev, Oleksii Ilchenko, Oleksandr Stanovyi, Pavlo Lishchuk, Oles Didukh, Sonya Rodichkina, Tetiana Nychyporuk, Victor Timoshenko, and Vladimir Lysenko
Affiliations : Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Str., Kiev 01601, Ukraine; D. F. Chebotaryov Institute for Gerontology, National Academy of Medical Sciences of Ukraine, 67 Vyshhorodska Str., 04114, Kyiv, Ukraine; D. F. Chebotaryov Institute for Gerontology, National Academy of Medical Sciences of Ukraine, 67 Vyshhorodseka Str., 04114, Kyiv, Ukraine; Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Str., Kiev 01601, Ukraine; Taras Shevchenko National University of Kyiv, 64/13, Volodymyrska Str., Kiev 01601, Ukraine; Faculty of Physics, Lomonosov Moscow State University, Leninskie Gory 1, Moscow, Russia 119991; University of Lyon, Nanotechnology Institute of Lyon, UMR CNRS 5270, INSA de Lyon, F69621, France; Faculty of Physics, Lomonosov Moscow State University, Leninskie Gory 1, Moscow, Russia 119991; University of Lyon, Nanotechnology Institute of Lyon, UMR CNRS 5270, INSA de Lyon, F69621, France

Resume : Continuous miniaturization and increasing of operating frequencies of electronic devices lead to overheating of their active zones. Therefore, all issues related to elaboration of thermal engineering approaches to perform an efficient heat evacuation from the overheated region are really crucial. In particular, the use of anisotropic nanomaterials allows orientation of heat fluxes along preferential directions due to a high ratio between their thermal conductivities in different directions. Raman technique is already known to be a powerful method for the thermal study of low-dimensional nanomaterials. One of the main advantages of this method is a possibility for contactless and non-destructive measurements. Its principle is based on dependence of relative intensities and spectral shifts of the Raman scattering on exciting laser intensity inducing local heating of the studied samples. Thus, both Raman peak position and Stokes/Anti Stokes ratio allow evaluation of the laser induced temperature rise. The experimental measurements coupled with theoretical models allow reliable evaluation of the thermal conductivity of the studied materials. During our talk, an efficient experimental approach based on Raman scattering measurements with variable laser spot sizes and shapes will be reported. Correlation between experimental and simulated thermal resistances of low-dimensional anisotropic nanocrystalline solids allows a simultaneous estimation of their thermal conductivities in different directions. In particular, our measurement approach is illustrated to be applied for anisotropic thermal conductivity evaluation of porous silicon and silicon nanowire arrays.

Authors : H. Zaoui, P. L. Palla, F. Cleri and E. Lampin
Affiliations : IEMN, Lille, France

Resume : Whenever Si nanostructures are intended to be part of electronics, photonics, thermoelectric, ..., devices, a crucial facet to ensure optimal performances is the heat management. Experimental characterization of heat transport at the nano scale is a difficult task, mainly because alternative heat paths confound the thermal response of the nano-component under study. Atomic-scale computer modelling can help understand heat transport in dedicated nanostructure models. In the present talk, we will present our latest achievements on the modelling of heat transport in Si nanostructures, nanowires and membranes. We generate and exploit a thermal transient at atomic scale by molecular dynamics, following the method we recently proposed, the approach-to-equilibrium molecular dynamics (AEMD). This method is faster than standard ones. Therefore we are able to overcome non physical effects due to a lack of convergence, and study real-size nanostructures. We will discuss the thermal regime in nanowires, and the maximum thermal conductivities. We will also present our theoretical results on nanopatterned membranes, and discuss their application to thermoelectric CMOS compatible devices.

Authors : Ceren Tayran, Oğuz Gülseren
Affiliations : Department of Physics, Gazi University, 06500, Ankara, Turkey; Department of of Physics, Bilkent University, 06800, Ankara, Turkey

Resume : Understanding nanoscale tribology provide fundamental insights for developing novel applications based on nanomaterials. To this end, in recent years, extensive work on friction of surfaces at atomistic scale have been carried out. The transition between atomic scale to macroscopic friction is largely studied using molecular dynamics methods (MD) [1]. However, understanding the atomic properties from ab initio calculations [2] enables us to evaluate detailed processes from stick-slip to energy dissipation occurred during frictional force microscopy experiments. The interpretation of the nano friction experiments needs more expressive models rather than basic Tomlinson model [3]. In this study, the frictional force between two graphene and functionalized graphene/graphene surfaces have been investigated by using first-principles calculations based on density functional theory. We considered three different geometric configurations which are bilayer graphene (perfect), B-doped graphene/graphene, N-doped graphene/graphene. Also, for the B and N doped graphene/graphene cases, we look at two geometries as top and hexagon. For analyzing the interlayer sliding pathways of perfect and doped graphene/graphene, there are two representative sliding directions: a short (S) (zigzag direction) and a long (L) (armchair direction) pathways. In these ways, one graphene layer (perfect and doped) has been moved relative to perfect graphene surface which is fixed. The binding energy, interlayer distance, frictional force and orbital nature of actual interactions are explored. Based on these calculations, we provide an understanding of the mechanism of interlayer sliding and frictional properties of bilayer perfect and doped graphene. This work is supported by TUBITAK Project No: 114F162. [1] Van Wijk, M.M. Dienwiebel, M., Frenken, J. W. M., Fasolino, A. “Superlubric to stick-slip sliding of incommensurate graphene flakes on graphite”, Phys. Rev. B., 88:235423 (2013). [2] Reguzzoni, M., Fasolino, A., Molinari, E., Righi, M. C., “Potential energy surface for graphene on graphene: Ab initio derivation, analytical description, and microscopic interpretation”, Phys. Rev. B., 86:245434 (2012). [3] Tomlinson, G., Philos. Mag. 7:905 (1929).

Authors : Jan Škarohlíd1, Peter Ashcheulov2, Radek Škoda1, Andrew Taylor2, Radim Čtvrtlík3, Jan Tomáštík3, František Fendrych2, Jaromír Kopeček2, Vladimír Cháb2, Stanislav Cichoň2, Petr Sajdl4, Jan Macák4, Peng Xu5, Jonna M. Partezana6, Jan Lorinčík7, Jana Prehradná1, Martin Steinbrück8 and Irena Kratochvílová2*
Affiliations : 1Czech Technical University in Prague, Faculty of Mechanical Engineering, Technická 4, Prague 6, CZ-160 07, Czech Republic 2Institute of Physics of the Czech Academy of Sciences, Na Slovance 2, CZ-182 21, Prague 8, Czech Republic 3RCPTM, Joint Laboratory of Optics of Palacký University in Olomouc and Institute of Physics of the Czech Academy of Sciences, 17. listopadu 12, CZ-771 46 Olomouc, Czech Republic 4University of Chemistry and Technology, Power Engineering Department, Technická 3, Prague 6, CZ-166 28, Czech Republic 5Nuclear Fuel Division, Westinghouse Electric Company, 5801 Bluff Road, Hopkins, SC 29209, USA 6Westinghouse Churchill Site, 1332 Beulah Rd., Pittsburgh, PA 15235, USA 7Research Centre Řež, Hlavní 130, CZ-250 68 Husinec-Řež, Czech Republic 8Institute for Applied Materials (IAM), Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany

Resume : Zirconium alloys can be effectively protected against corrosion in nuclear reactor hot stem or hot water environment by polycrystalline diamond films grown in microwave plasma enhanced linear antenna chemical vapor deposition apparatus. Hot steam and hot water oxidized PCD layers grown on Zr surfaces were investigated. It was found that the presence of the PCD coating blocks hydrogen and oxygen intact into the Zr surface and protects Zr material from degradation. PCD anticorrosion protection of Zr alloy can significantly prolong life of Zr material claddings in nuclear reactors and consequently enhance nuclear fuel burnup. Detailed description of the polycrystalline diamond role in corrosion process is presented.


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Symposium organizers
Ádám GALIWigner Research Centre for Physics

Hungarian Academy of Sciences, Konkoly-Thege Miklós út 29-33, Budapest, 1121, Hungary

+36 1 392 2222/1913
Jan VALENTACharles University

Ke Karlovu 3, Prague 2, CZ-121 16 Czechia

+420 2 2191 1272
Milos NESLADEKUniversity Hasselt, IMOMEC, IMEX

Wetenschapspark 1, B 3591 Diepenbeek, Belgium

+ 3211268833
Minoru FUJIIKobe University

Dept. of Electrical and Electronic Engineering Rokkodai, Nada, Kobe 657-8501 Japan