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1. Iuliacumite: A Novel Chemical Short-Range Order in a Two-Dimensional Wurtzite Single Monolayer InAs 1– x Sb x Shell on InAs Nanowires

Author

J.P. Nys, Sebastien Plissard, Maxime Berthe, Rafal E. Dunin-Borkowski, Ph. Ebert, Tao Xu, I. Lefebvre, Bruno Grandidier, Holger Eisele, M. Schnedler, Jülich Research Centre, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Équipe Matériaux et Procédés pour la Nanoélectronique (LAAS-MPN), Laboratoire d'analyse et d'architecture des systèmes (LAAS), Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Technische Universität Berlin (TU), Physique-IEMN (PHYSIQUE-IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Physique - IEMN (PHYSIQUE - IEMN), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Technical University of Berlin / Technische Universität Berlin (TU), ACKNOWLEDGMENTSThe authors thank P. Caroff for his involvement in thenanowire growth and the European Community’s H2020program (Grant No. PITN-GA-2016-722176, Indeed Project),the EQUIPEX programs Excelsior (Grant No. ANR-11-EQPX-0015), the RENATECH network, the Deutsche Forschungs-gemeinschaft (DFG, German research foundation, 390247238), the Natural Science Foundation of Shanghai(19ZR1419500) and of the Region Nord-Pas-de-Calais for financial support., RENATECH network, and ANR-11-EQPX-0015,Excelsior,Centre expérimental pour l'étude des propriétés des nanodispositifs dans un large spectre du DC au moyen Infra-rouge.(2011)

Subjects
Materials science, Condensed matter physics, Chemical ordering, Single monolayer, Mechanical Engineering, Shell (structure), Nanowire, Nanowire shell, Bioengineering, In(As, 02 engineering and technology, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Sb), Monolayer, ddc:660, Short range order, General Materials Science, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology, Wurtzite, Wurtzite crystal structure
Abstract

International audience; A chemical short range order is found in single monolayer InAs 1-x Sb x shells, which inherit a wurtzite structure from the underlying InAs nanowire, instead of crystallizing in the energetically preferred zincblende structure. The chemical order is characterized by an anti-correlation ordering vector in 1120 direction and arises from strong Sb-Sb repulsive interactions along the atomic chains in 1120 direction.

Published
2019
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2. Shallow Heavily Doped n++ Germanium by Organo-Antimony Monolayer Doping

Author

Marc Veillerot, Virginie Enyedi, Chloé Thieuleux, J.P. Nys, Névine Rochat, Thibault Alphazan, Eugénie Martinez, Helen Grampeix, Maxime Berthe, François Martin, Adrian Díaz Álvarez, Bruno Grandidier, Marc Dewitte, and Didier Stiévenard

Subjects
010302 applied physics, Materials science, Dopant, Passivation, Inorganic chemistry, Doping, chemistry.chemical_element, Germanium, 02 engineering and technology, Dopant Activation, 021001 nanoscience & nanotechnology, 01 natural sciences, Overlayer, chemistry, 0103 physical sciences, Monolayer, General Materials Science, Wafer, 0210 nano-technology
Abstract

Functionalization of Ge surfaces with the aim of incorporating specific dopant atoms to form high-quality junctions is of particular importance for the development of solid-state devices. In this study, we report the shallow doping of Ge wafers with a monolayer doping strategy that is based on the controlled grafting of Sb precursors and the subsequent diffusion of Sb into the wafer upon annealing. We also highlight the key role of citric acid in passivating the surface before its reaction with the Sb precursors and the benefit of a protective SiO2 overlayer that enables an efficient incorporation of Sb dopants with a concentration higher than 1020 cm–3. Microscopic four-point probe measurements and photoconductivity experiments show the full electrical activation of the Sb dopants, giving rise to the formation of an n++ Sb-doped layer and an enhanced local field-effect passivation at the surface of the Ge wafer.

Published
2017

3. Estimation of {\pi}-{\pi} Electronic Couplings from Current Measurements

Author

Akira Fujiwara, Yoann Olivier, Jérôme Cornil, Jérôme Rech, Ragavendran Sivakumarasamy, Philippe Leclère, Nicolas Clement, J.P. Nys, Olivier Alévêque, Eric Levillain, Thierry Martin, Dominique Vuillaume, Kacem Smaali, Valentin Diez-Cabanes, Didier Theron, Jorge Trasobares, Thibaut Jonckheere, Institut d’Électronique, de Microélectronique et de Nanotechnologie (IEMN) - UMR 8520 (IEMN), Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Université Polytechnique Hauts-de-France (UPHF)-Ecole Centrale de Lille-Université Polytechnique Hauts-de-France (UPHF)-Institut supérieur de l'électronique et du numérique (ISEN), Centre de Physique Théorique - UMR 7332 (CPT), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), CPT - E6 Nanophysique, Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), MOLTECH-ANJOU (MOLTECH-ANJOU), Université d'Angers (UA)-Centre National de la Recherche Scientifique (CNRS), Univ Mons, Lab Chem Novel Mat, Belgium, Université de Mons (UMons), NTT Basic Research Laboratories [Tokio], NTT Basic Research Laboratories, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), MOLTECH-Anjou, Institut de Chimie du CNRS (INC)-Université d'Angers (UA)-Centre National de la Recherche Scientifique (CNRS), Nano and Microsystems - IEMN (NAM6 - IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-JUNIA (JUNIA), Renatech Network, ANR-11-EQPX-0015,Excelsior,Centre expérimental pour l'étude des propriétés des nanodispositifs dans un large spectre du DC au moyen Infra-rouge.(2011), European Project: 317116,EC:FP7:PEOPLE,FP7-PEOPLE-2012-ITN,NANOMICROWAVE(2013), European Project: 642196,H2020,H2020-MSCA-ITN-2014,iSwitch(2015), Université d'Angers (UA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Nanostructures, nanoComponents & Molecules - IEMN (NCM - IEMN)

Subjects
molecular electronics, Gaussian, Bioengineering, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Molecular physics, [SPI]Engineering Sciences [physics], symbols.namesake, Quantum mechanics, General Materials Science, nanoelectrochemistry, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], Diode, Coupling, Range (particle radiation), π−π interaction, Nanoelectrochemistry, Condensed Matter - Mesoscale and Nanoscale Physics, Chemistry, Mechanical Engineering, Intermolecular force, Cooperative effect, Molecular electronics, General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, transfer integral, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, coupled quantum dot, symbols, Density functional theory, 0210 nano-technology
Abstract

The {\pi}-{\pi} interactions between organic molecules are among the most important parameters for optimizing the transport and optical properties of organic transistors, light-emitting diodes, and (bio-) molecular devices. Despite substantial theoretical progress, direct experimental measurement of the {\pi}-{\pi} electronic coupling energy parameter t has remained an old challenge due to molecular structural variability and the large number of parameters that affect the charge transport. Here, we propose a study of {\pi}-{\pi} interactions from electrochemical and current measurements on a large array of ferrocene-thiolated gold nanocrystals. We confirm the theoretical prediction that t can be assessed from a statistical analysis of current histograms. The extracted value of t ca. 35 meV is in the expected range based on our density functional theory analysis. Furthermore, the t distribution is not necessarily Gaussian and could be used as an ultrasensitive technique to assess intermolecular distance fluctuation at the subangstr\"om level. The present work establishes a direct bridge between quantum chemistry, electrochemistry, organic electronics, and mesoscopic physics, all of which were used to discuss results and perspectives in a quantitative manner., Comment: Nano Lett (2017), full text and supporting information

Published
2017
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4. As antisite incorporation in epitaxial growth of GaAs

Author

Didier Stiévenard, J.P. Nys, J. Nagle, Christophe Delerue, M. Stellmacher, Bruno Grandidier, M. Lannoo, H Hammadi, and Jacques Bourgoin

Subjects
Materials science, Analytical chemistry, Infrared spectroscopy, Chemical vapor deposition, Condensed Matter Physics, Epitaxy, Electronic, Optical and Magnetic Materials, law.invention, Metal, law, visual_art, visual_art.visual_art_medium, Molecule, Growth rate, Electrical and Electronic Engineering, Scanning tunneling microscope, Molecular beam epitaxy
Abstract

We have studied the incorporation of As antisite defects in GaAs during epitaxial growth. The growths have been performed by molecular beam epitaxy at low temperature, by metal organic chemical vapor deposition and by a special chemical vapor phase technique allowing to reach very high growth rates (up to 5 μm/min). The As antisite concentration is measured by electrical techniques or by infrared absorption at 1 μm, and through the change of the lattice mismatch and scanning tunneling microscopy in the case of large concentrations. The study is performed by monitoring the antisite concentration versus the growth temperature at constant growth rate and versus the growth rate at constant temperature. The results can be understood in terms of incorporation of As 2 molecules during the two different regimes by which epitaxial growth takes place.

Published
1999
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5. Nanoscale desorption of H-passivated Si(100)–2×1 surfaces using an ultrahigh vacuum scanning tunneling microscope

Author

D. Stievenard, J.P. Nys, C. Syrykh, and Bernard Legrand

Subjects
Materials science, business.industry, Scanning tunneling spectroscopy, Analytical chemistry, General Physics and Astronomy, Spin polarized scanning tunneling microscopy, Electrochemical scanning tunneling microscope, law.invention, Scanning probe microscopy, Laser linewidth, law, Optoelectronics, Vacuum chamber, Scanning tunneling microscope, business, Electron-beam lithography
Abstract

Nanoscale desorption of the Si(100)–2×1 hydrogen terminated surface has been achieved using a scanning tunneling microscope (STM) in an ultrahigh vacuum chamber. We have studied the patterned linewidth as a function of the sample bias and the dose, either with the feedback servo loop on or off. We propose a simple analytical model to explain the variation of the linewidth versus the electron dose. Finally, we show that the best resolution is obtained for pulsed voltages with the STM feedback servo loop on.

Published
1999
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6. Band offsets at zincblende-wurtzite GaAs nanowire sidewall surfaces

Author

P. Capiod, Liverios Lymperakis, Ph. Ebert, Jörg Neugebauer, Tao Xu, Maxime Berthe, Rafal E. Dunin-Borkowski, J.P. Nys, Gilles Patriarche, Philippe Caroff, Bruno Grandidier, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Key Laboratory of Advanced Display and System Application, Shanghai University, Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Gesellschaft, Department of Electronic Materials Engineering, Australian National University (ANU), Peter Grünberg Institut, and Peter Grünberg Institut (PGI)

Subjects
Materials science, Physics and Astronomy (miscellaneous), Band gap, Scanning tunneling spectroscopy, Nanowire, 02 engineering and technology, 01 natural sciences, law.invention, Physics::Fluid Dynamics, Condensed Matter::Materials Science, symbols.namesake, [SPI]Engineering Sciences [physics], law, Condensed Matter::Superconductivity, 0103 physical sciences, ddc:530, 010306 general physics, Electronic band structure, Wurtzite crystal structure, Condensed matter physics, business.industry, Fermi level, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Semiconductor, symbols, Scanning tunneling microscope, 0210 nano-technology, business
Abstract

The band structure and the Fermi level pinning at clean and well-ordered sidewall surfaces of zincblende (ZB)-wurtzite (WZ) GaAs nanowires are investigated by scanning tunneling spectroscopy and density functional theory calculations. The WZ-ZB phase transition in GaAs nanowires introduces p-i junctions at the sidewall surfaces. This is caused by the presence of numerous steps, which induce a Fermi level pinning at different energies on the non-polar WZ and ZB sidewall facets.

Published
2013
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7. Iron silicide growth on Si(111) substrate using the metalorganic vapour phase epitaxy process

Author

H. Alaoui, J.F. Pétroff, J.P. Nys, Y. Zheng, J. P. André, X. Wallart, and A. Deswarte

Subjects
Silicon, Analytical chemistry, Mineralogy, chemistry.chemical_element, Substrate (electronics), Condensed Matter Physics, Iron pentacarbonyl, Inorganic Chemistry, chemistry.chemical_compound, chemistry, Silicide, Materials Chemistry, Direct and indirect band gaps, Metalorganic vapour phase epitaxy, Disilane, Thin film
Abstract

Iron silicide thin films (∈-FeSi, α-FeSi 2 and β-FeSi 2 ) were grown on silicon (111) substrates using the metalorganic vapour phase epitaxy (MOVPE) process with iron pentacarbonyl (Fe(CO) 5 ) and disilane (Si 2 H 6 ) precursors. Attention was mainly paid to the β-FeSi 2 phase. Transmission electron microscopy (TEM) and X-ray diffraction measurements allowed optimization of the growth process and revealed the nature and structure of the layers grown on the silicon substrate. A growth model is discussed and the action of the thermal annealing, which leads to the coalescence of the dendrites to form a continuous film of β-FeSi 2 up to about 1000 A thick, is described. Finally a photoluminescence signal has been detected in the range of the expected direct band gap value of β-FeSi 2 .

Published
1994
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8. Combined STM and four-probe resistivity measurements on single semiconductor nanowires

Author

Maxime Berthe, Corentin Durand, Tao Xu, Philippe Caroff, Bruno Grandidier, J.P. Nys, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Subjects
Materials science, Switch Unit, Scanning electron microscope, Scanning Tunneling Microscope Image, Instrumentation, Nanowire, Single Semiconductor, 02 engineering and technology, 01 natural sciences, Atomic units, law.invention, [SPI]Engineering Sciences [physics], law, Electrical resistivity and conductivity, 0103 physical sciences, 010306 general physics, business.industry, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Resolution Scanning Tunneling Microscope, Electrical contacts, Probe Scan Tunneling Microscope, Semiconductor, Optoelectronics, Scanning tunneling microscope, 0210 nano-technology, business
Abstract

International audience; Transport measurements on free-standing nanostructures with clean and reconstructed facets require an instrumentation based on electrical probes that scan materials at the atomic scale with fine tuning in the establishment of the electrical contact. We describe a multiple probe tunneling microscope that operates under a scanning electron microscope in ultra-high vacuum and fulfills these requirements thanks to a unique control system. We show how this instrument is well adapted to study the resistivity of semiconductor nanowires.

Published
2011
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9. Study of the epitaxy of β-FeSi2 by codeposition of Fe and Si on Si(111)

Author

O. Dehaese, J.P. Nys, G. Vincent, and Xavier Wallart

Subjects
Materials science, Annealing (metallurgy), Analytical chemistry, General Physics and Astronomy, Mineralogy, Surfaces and Interfaces, General Chemistry, Thin film, Condensed Matter Physics, Epitaxy, Surfaces, Coatings and Films
Abstract

In this work, we investigate the epitaxy of β-FeSi2 on Si(111) using an Fe and Si codeposition method. We show that, in order to grow FeSi2 in its β phase, a template is needed. The resulting films exhibit a better cristallography and morphology than those grown by the solid phase epitaxy (SPE) method.

Published
1993
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10. H–Si doping profile in GaAs by scanning tunneling microscopy

Author

Eugene Constant, Jacques Chevallier, Bruno Grandidier, D. Bernard, Didier Stiévenard, Thierry Melin, Santiago Silvestre, and J.P. Nys

Subjects
Physics and Astronomy (miscellaneous), Dopant, Silicon, Hydrogen, Scanning tunneling spectroscopy, Doping, Analytical chemistry, Conductance, chemistry.chemical_element, Conductivity, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, law.invention, Condensed Matter::Materials Science, chemistry, law, Condensed Matter::Superconductivity, Scanning tunneling microscope
Abstract

Hydrogen incorporation in n-type Si-doped GaAs layers results in the neutralization of the active dopants and a change of the conductivity along the growth direction. To characterize the active dopant concentration of doped GaAs layers containing hydrogen, we have used secondary ion mass spectroscopy and cross-sectional scanning tunneling microscopy. Spectroscopic measurements are performed as well as conductance images to visualize the variation of the conduction band-edge position. Such a variation, which is related to the concentration of Si–H complexes, allows the determination of the doping profile.

Published
2001
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11. Study of the effect of gas pressure and catalyst droplets number density on silicon nanowires growth, tapering, and gold coverage

Author

D. Stievenard, Rodrigue Lardé, Tao Xu, Philippe Pareige, J.P. Nys, Bruno Grandidier, Wanghua Chen, Emmanuel Cadel, Groupe de physique des matériaux (GPM), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Subjects
inorganic chemicals, Materials science, Silicon, Nanowire, General Physics and Astronomy, chemistry.chemical_element, Nanotechnology, 02 engineering and technology, Substrate (electronics), Chemical vapor deposition, 01 natural sciences, chemistry.chemical_compound, 0103 physical sciences, 010302 applied physics, Number density, technology, industry, and agriculture, Partial pressure, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, Silane, chemistry, Chemical engineering, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 0210 nano-technology, Molecular beam epitaxy
Abstract

We investigated the growth of silicon nanowires from Au-rich catalyst droplets by two different methods: chemical vapor deposition (CVD) and molecular beam epitaxy (MBE). The growth rate is found to be diameter-dependent and increases with increasing precursor partial pressures. The comparison of the experimental results with models shows that the contribution of Si atoms that diffuses from the substrate and the NW sidewalls toward the catalyst droplet can be neglected in CVD for the different pressures used in this study, whereas it is the major source of Si supply for the MBE growth. In addition, by decreasing the number density of catalyst droplet prior to the NW growth in CVD, it is also found that this parameter affects the NWs morphology, increasing the tapering effect when the silane partial pressure is small enough to allow gold atom diffusion from the catalyst droplet.

Published
2010
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12. Atomic-scale study of GaMnAs/GaAs layers

Author

J.P. Nys, Bruno Grandidier, Masaaki Tanaka, Y. Higo, Christophe Delerue, and Didier Stiévenard

Subjects
Materials science, Physics and Astronomy (miscellaneous), Condensed matter physics, Dopant, Fermi level, Analytical chemistry, Magnetic semiconductor, Acceptor, law.invention, Gallium arsenide, symbols.namesake, chemistry.chemical_compound, Ferromagnetism, chemistry, law, symbols, Scanning tunneling microscope, Molecular beam epitaxy
Abstract

Cross-sectional scanning tunneling microscopy was used to study GaMnAs diluted magnetic semiconductors grown by low temperature molecular beam epitaxy. The Ga1−xMnxAs layer, containing a concentration of x=0.005, shows that the dominant defect in the material is the arsenic antisite. Mn ions can also be resolved and show a signature distinct from the arsenic antisites. Spectroscopic measurements are perfomed to study the variation of the Fermi level between the Ga0.995Mn0.005As and GaAs layers. The Mn ions act as acceptor dopants. However, for x=0.005, the Mn concentration in comparison with the As antisite concentration is too small to induce a significant change of the Fermi level from the midgap position, preventing the layer from being ferromagnetic.

Published
2000
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13. Electron spectroscopy study of the FeSi(111) and FeSi2Si(111) interface formation

Author

J.P. Nys, Xavier Wallart, G. Dalmai, and H. S. Zeng

Subjects
Auger electron spectroscopy, Reflection high-energy electron diffraction, Materials science, Low-energy electron diffraction, Scanning electron microscope, Mechanical Engineering, Electron energy loss spectroscopy, Analytical chemistry, Condensed Matter Physics, Electron spectroscopy, Mechanics of Materials, General Materials Science, Electron beam-induced deposition, Electron backscatter diffraction
Abstract

In this work, we characterize the reaction of thin iron films deposited on Si(111) substrates upon annealing in the temperature range 200–600°C with Auger electron spectroscopy, electron energy loss spectroscopy, low energy electron diffraction and scanning electron microscopy. We particularly stress the conditions of formation and epitaxy of the disilicide FeSi 2 .

Published
1991
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14. Quantum box size effect on vertical self-alignment studied using cross-sectional scanning tunneling microscopy

Author

D. Stievenard, Jean-Michel Gérard, Aristide Lemaître, V. Thierry-Mieg, Bruno Grandidier, J.P. Nys, and Bernard Legrand

Subjects
Physics and Astronomy (miscellaneous), Condensed matter physics, Chemistry, Quantum point contact, Spin polarized scanning tunneling microscopy, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Layer thickness, law.invention, Gallium arsenide, Condensed Matter::Materials Science, chemistry.chemical_compound, law, Self alignment, Scanning tunneling microscope, Layer (electronics), Quantum
Abstract

InAs quantum boxes separated by GaAs spacer layers are known to exhibit a vertical self-organization along the growth direction. The alignment probability between two sets of quantum boxes depends strongly on the spacer layer thickness Zs. In this letter, we study samples containing multiple arrays of quantum boxes separated by GaAs spacer layers of various thicknesses, using cross-sectional scanning tunneling microscopy. This work experimentally evidences that the spacer layer characteristic thickness Zs0 below which a vertical self-alignment occurs, depends on the size of the quantum boxes. These results are interpreted using a theoretical two-dimensional model.

Published
1999
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15. Resistivity and surface states density of n and p type silicon nanowires

Author

Didier Stiévenard, Bruno Grandidier, J.P. Nys, Dominique Deresmes, F. Vaurette, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Subjects
010302 applied physics, Materials science, Silicon, Condensed matter physics, business.industry, Nanowire, chemistry.chemical_element, 02 engineering and technology, P type silicon, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Capacitance, Semiconductor, chemistry, Electrical resistivity and conductivity, 0103 physical sciences, Electrical measurements, Electrical and Electronic Engineering, 0210 nano-technology, business, Surface states
Abstract

The resistivity and the density of surface states of semiconductor nanowires are not measurable using classic electrical measurements such as capacitance-voltage techniques, because of too low capacitance associated with a single nanowire. To overcome this problem, the authors measured the resistance of a set of n- and p-doped silicon nanowires versus their length and width. Thus, the authors deduce both the resistivity and density of surface states of the nanowires. This approach could be extended to any nanowire, once its shape is known.

Published
2008
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16. Growth of Si nanowires on micropillars for the study of their dopant distribution by atom probe tomography

Author

D. Stievenard, Bruno Grandidier, J.P. Nys, Y. Coffinier, Rabah Boukherroub, Emmanuel Cadel, Philippe Pareige, Rodrigue Lardé, Tao Xu, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Subjects
Materials science, Silicon, Nanowire, Physics::Optics, chemistry.chemical_element, Nanotechnology, 02 engineering and technology, Atom probe, 01 natural sciences, Atomic units, law.invention, Impurity, law, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Electrical and Electronic Engineering, Boron, 010302 applied physics, Dopant, business.industry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, chemistry, Femtosecond, Optoelectronics, 0210 nano-technology, business
Abstract

This article reports on the growth of Au islands on the Si(111) surface as a function of the Au evaporation rate and the temperature of the surface in ultrahigh vacuum. By controlling the density of the Au islands and their size, it is possible to subsequently grow single vertically oriented Si nanowires on top of (111)-oriented silicon micropillar and analyze their chemical composition at the atomic scale with the femtosecond laser assisted tomographic atom probe. Three-dimensional images of the atom distribution in the nanowire, in particular, the distribution of boron impurities, are obtained and compared to the intended impurity concentration.

Published
2008
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17. Evidence of electron-phonon interaction on transport in n- and p-type silicon nanowires

Author

Bruno Grandidier, François Vaurette, J.P. Nys, Dominique Deresmes, D. Stievenard, Renaud Leturcq, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Subjects
Elementary particle interactions, Electron mobility, Materials science, Physics and Astronomy (miscellaneous), Silicon, Nanowire, Phonon scattering, chemistry.chemical_element, 02 engineering and technology, 01 natural sciences, [SPI]Engineering Sciences [physics], Electrical resistivity and conductivity, Electrostatics, 0103 physical sciences, Doping, Surface scattering, Ohmic contacts, 010302 applied physics, Condensed matter physics, Scattering, Nanowires, Quantum wire, Electron phonon, P type silicon, Transition metals, 021001 nanoscience & nanotechnology, Electronic transport, chemistry, Chemical elements, 0210 nano-technology
Abstract

The authors studied the transport in n- and p-type silicon nanowires. When the temperature decreases from 325to75K, they observed a variation of the nanowire resistance, consistent with a transport governed by electron-phonon scattering. The lateral size of the nanowire down to 25nm is not found to cause further surface scattering, due to the presence of interface states which create a depleted region in the nanowires. Such depleted region allows thus to keep a carrier mobility in the nanowires similar to the bulk one.

Published
2008
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18. Scanning tunneling microscopy and scanning tunneling spectroscopy of self-assembled InAs quantum dots

Author

J.P. Nys, Bruno Grandidier, Didier Stiévenard, Jean-Michel Gérard, V. Thierry-Mieg, and Bernard Legrand

Subjects
Materials science, Physics and Astronomy (miscellaneous), Condensed matter physics, Scanning tunneling spectroscopy, Scanning gate microscopy, Spin polarized scanning tunneling microscopy, Scanning capacitance microscopy, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Electrochemical scanning tunneling microscope, law.invention, Condensed Matter::Materials Science, Scanning probe microscopy, law, Quantum dot, Scanning tunneling microscope
Abstract

We present cross-sectional scanning tunneling microscopy images and scanning tunneling spectroscopy results of InAs quantum dots grown on GaAs. The samples contain 12 arrays of quantum dots. The analysis of the scanning tunneling microscope images reveals the self-alignment of the dots as well as the different dot interfaces with the under- and overgrown GaAs layers. We measure the strain distribution along the [001] direction in the (110) plane. The roughness of the dot interfaces along the [110] direction is also estimated and local spectroscopy of the dots evidences the electronic confinement (measured gap of 1.25 eV compared with 0.4 eV for bulk InAs).

Published
1998
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19. Microscopic behavior of silicon in silicon delta-doped layer in GaAs

Author

Xavier Wallart, Bruno Grandidier, D. Stievenard, and J.P. Nys

Subjects
inorganic chemicals, Materials science, Physics and Astronomy (miscellaneous), Silicon, Scanning tunneling spectroscopy, Doping, technology, industry, and agriculture, Analytical chemistry, chemistry.chemical_element, complex mixtures, Electrochemical scanning tunneling microscope, law.invention, Gallium arsenide, chemistry.chemical_compound, chemistry, law, Monolayer, Scanning tunneling microscope, Molecular beam epitaxy
Abstract

Silicon δ-doped layers in GaAs have been studied using scanning tunneling microscopy and scanning tunneling spectroscopy on cleaved (110) surfaces. The samples were grown using molecular beam epitaxy with two growth temperatures: 480 and 580 °C. The concentration of the δ-doped layer was 0.03 monolayer. We show that, as in the case of bulk doping, the silicon has an amphoteric character: both SiGa and SiAs are observed at 480 °C and donors are formed before acceptors. At 580 °C, the spatial repartition of silicon evidences the segregation of silicon.

Published
1998
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20. Influence of barrier height on scanning tunneling spectroscopy experimental and theoretical aspects

Author

Christophe Delerue, D. Stievenard, X. de la Broise, Bruno Grandidier, M. Lannoo, and J.P. Nys

Subjects
Physics and Astronomy (miscellaneous), Condensed matter physics, Chemistry, Scanning tunneling spectroscopy, Analytical chemistry, chemistry.chemical_element, Spin polarized scanning tunneling microscopy, Tungsten, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Electrochemical scanning tunneling microscope, law.invention, Condensed Matter::Materials Science, law, Condensed Matter::Superconductivity, Density of states, Scanning tunneling microscope, Quantum tunnelling, Surface states
Abstract

Scanning tunneling spectroscopy allows the determination of the density of states of the involved electrodes as well as the associated barrier height. We have measured the barrier height between tungsten tip and the GaAs (110) surface with a scanning tunneling microscope (STM) in ultrahigh vacuum. When the tunneling junction exhibited a low barrier height, we observed and explained an apparent widening of the GaAs gap which can mislead the real doping concentration of the sample. A theoretical model based on the self-consistent Keldysh–Green functions formalism is used to calculate the STM current. It shows a possible lowering of the barrier height according to the adsorption of As or Ga atoms on the apex of the tungsten tip.

Published
1998
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21. Compensation mechanisms in low-temperature-grown Ga1-xMnxAs investigated by scanning tunneling spectroscopy

Author

G. Mahieu, D. Stievenard, P. Condette, Masaaki Tanaka, Bruno Grandidier, H. Shimizu, Ph. Ebert, J.P. Nys, Guy Allan, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Subjects
Materials science, Physics and Astronomy (miscellaneous), Condensed matter physics, Dopant, Scanning tunneling spectroscopy, Fermi level, Magnetic semiconductor, Acceptor, law.invention, symbols.namesake, [SPI]Engineering Sciences [physics], law, symbols, Charge carrier, ddc:530, Scanning tunneling microscope, Spectroscopy
Abstract

Ga1-xMnxAs layers with Mn composition of up to 6.2% are investigated by cross-sectional scanning tunneling microscopy and spectroscopy. We identify in the tunneling spectra contributions from Mn-Ga(-) acceptor states, compensating As-Ga(2+) donor states, and additional compensating donor states, which we suggest to be Mn-i(2+) interstitials. On basis of the observed Fermi level shift and a charge carrier compensation analysis, we deduce the concentration of Mn-i(2+) interstitials. Furthermore, scanning tunneling microscopy images suggest an inhomogeneous distribution of Mn dopant atoms. (C) 2003 American Institute of Physics.

Published
2003
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22. Formation of silicon islands on a silicon on insulator substrate upon thermal annealing

Author

J.P. Nys, D. Stievenard, Vincent Agache, Vincent Senez, Bernard Legrand, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), and Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)

Subjects
010302 applied physics, Auger electron spectroscopy, Materials science, Physics and Astronomy (miscellaneous), Silicon, Annealing (metallurgy), Nanocrystalline silicon, Analytical chemistry, chemistry.chemical_element, Coulomb blockade, Silicon on insulator, 02 engineering and technology, Thermal treatment, 021001 nanoscience & nanotechnology, 01 natural sciences, [SPI]Engineering Sciences [physics], chemistry, 0103 physical sciences, Vacuum chamber, Composite material, 0210 nano-technology
Abstract

Starting from silicon on insulator substrates, we show that a thermal treatment (in the 600–900 °C range) induces the creation of silicon islands. To characterize the island formation as well as the initial silicon layer thickness, we use in situ Auger electron spectroscopy analysis in an ultrahigh vacuum chamber. The island size and density are studied with an ex situ atomic force microscope. We show that the formation temperature of the islands increases from 575 to 875 °C as the initial silicon layer thickness increases from 1 to 19 nm. For the 1 nm thickness, the minimum island size is reached (semispherical shape with a 16 nm diameter). The phenomena involved in the island formation are discussed and the study of the variations of the calculated stress tensor (IMPACT software) as a function of the thermal treatment explain the behavior of the top silicon layer.

Published
2000
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23. Correlation between electrical and microscopic properties of TiSi interfaces

Author

J.P. Nys, H. S. Zeng, G. Dalmai, and X Wallart

Subjects
In situ, Materials science, Electron energy, Condensed matter physics, Electrical resistivity and conductivity, Interface (computing), Analytical chemistry, Condensed Matter Physics, Instrumentation, Surfaces, Coatings and Films, Auger
Abstract

We present a detailed investigation of the interface formation in the TiSi system at low temperatures (25–300°C). Accurate Auger and Electron Energy Loss measurements and analysis are used to study the microscopic properties of the interfaces. The correlation between these properties and in situ resistivity measurements is discussed.

Published
1990
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24. Evidence of Ge island formation during thermal annealing of SiGe alloys: Combined atomic force microscopy and Auger electron spectroscopy study

Author

D. Stievenard, Dirk J. Gravesteijn, Xavier Wallart, C. Tételin, and J.P. Nys

Subjects
Semiconductor thin films, Auger electron spectroscopy, symbols.namesake, Crystallography, Materials science, Auger effect, Atomic force microscopy, Chemical physics, Annealing (metallurgy), Semiconductor materials, General Engineering, symbols, Atmospheric temperature range
Abstract

The effect of thermal annealing on the composition and morphology of the surface of strained SiGe layers grown on Si is investigated in the temperature range 400–900 °C. We show that Ge segregation starts at 400 °C and increases with increasing temperature. Above 700 °C, strain relaxation leads to the formation of islands on the surface. By combining atomic force microscopy and Auger electron spectroscopy we demonstrate that these islands are Ge rich and that at 900 °C rather pure Ge islands are formed on a Si rich underlying layer.

Published
1998
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25. Importance of point defect reactions for the atomic-scale roughness of III–V nanowire sidewalls

Author

Gilles Patriarche, Philippe Caroff, J.P. Nys, Tao Xu, Adrian Díaz Álvarez, Bruno Grandidier, Philipp Ebert, Nathali Alexandra Franchina Vergel, Nemanja Peric, Jean-Christophe Harmand, Maxime Berthe, Sebastien Plissard, Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520 (IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Centre de Nanosciences et Nanotechnologies (C2N (UMR_9001)), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Équipe Matériaux et Procédés pour la Nanoélectronique (LAAS-MPN), Laboratoire d'analyse et d'architecture des systèmes (LAAS), Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Peter Grünberg Institute, Forschungszentrum Jülich GmbH | Centre de recherche de Juliers, Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association, University of Shanghai [Shanghai], Physique-IEMN (PHYSIQUE-IEMN), Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF)-Centrale Lille-Institut supérieur de l'électronique et du numérique (ISEN)-Université de Valenciennes et du Hainaut-Cambrésis (UVHC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Université Polytechnique Hauts-de-France (UPHF), Physique - IEMN (PHYSIQUE - IEMN), EPItaxie et PHYsique des hétérostructures - IEMN (EPIPHY - IEMN), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), AcknowledgmentsThis work was financially supported by the European Community’s Seventh Framework Program (Grant No. PITN-GA-2012-316751, Nanoembrace project), the H2020 program(Grant No. PITN-GA-2016-722176, Indeed Project), theFrench state funds managed by the ANR within theFigure 7. STM image of the {110} sidewall of a In-catalyzed InAsNWs after the removal of the As capping layer at 315 °C–325 °C.Tunneling conditions: V sample = +2.5 V, I tunneling = 10 pA.Figure 8. Sequence of temperature-dependent STEM images of anAu-catalyzed GaAs NW capped with a thin As cap. The annealingtemperature is indicated in the images. 7Nanotechnology 30 (2019) 324002 A Díaz Álvarez et alInvestissements d’Avenir programme (Grant No. ANR-11-EQPX-0015, EQUIPEX Excelsior, Grant No. ANR-10-EQPX-0050), EQUIPEX Tempos), the French National ResearchAgency (ANR-16-CE24-0007-01, Dirac III-V project) and theRENATECH network and the Deutsche For-schungsgemeinschaft (Grant No. 390247238). T Xuacknowledges the supports of the National Natural ScienceFoundation of China (Grant No. 61775130). The authors thankC Coinon and X Wallart for the growth of the As capped bulksamples and C Domke, M Heinrich, M Simon, and C Dzeja forparticipating in some of the measurements leading to figure 4, RENATECH network, ANR-10-EQPX-0050,TEMPOS,Microscopie electronique en transmission sur le plateau Palaiseau Orsay Saclay(2010), and ANR-16-CE24-0007,Dirac-III-V,Super-réseau d'antipoints de Dirac pour les électrons dans les semiconducteurs III-V(2016)

Subjects
Materials science, Annealing (metallurgy), Nucleation, Nanowire, Bioengineering, 02 engineering and technology, Surface finish, 010402 general chemistry, 01 natural sciences, law.invention, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], law, Vacancy defect, Scanning transmission electron microscopy, [CHIM.CRIS]Chemical Sciences/Cristallography, surface morphology, General Materials Science, Electrical and Electronic Engineering, roughness, {110} sidewall, Condensed matter physics, business.industry, point defect, Mechanical Engineering, III-V semiconductor nanowires, [CHIM.MATE]Chemical Sciences/Material chemistry, General Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Semiconductor, Mechanics of Materials, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], scanning tunneling microscopy, Scanning tunneling microscope, 0210 nano-technology, business
Abstract

International audience; The surface morphology of III-V semiconductor nanowires (NWs) protected by an arsenic cap and subsequently evaporated in ultrahigh vacuum is investigated with scanning tunneling microscopy and scanning transmission electron microscopy. We show that the changes of the surface morphology as a function of the NW composition and the nature of the seed particles are intimately related to the formation and reaction of surface point defects. Langmuir evaporation close to the congruent evaporation temperature causes the formation of vacancies which nucleate and form vacancy islands on {110} sidewalls of self-catalyzed InAs NWs. However, for annealing temperatures much smaller than the congruent temperature, a new phenomenon occurs: group III vacancies form and are filled by excess As atoms, leading to surface As Ga antisites. The resulting Ga adatoms nucleate with excess As atoms at the NW edges, producing monoatomic-step islands on the {110} sidewalls of GaAs NWs. Finally, when gold atoms diffuse from the seed particle onto the {110} sidewalls during evaporation of the protective As cap, Langmuir evaporation does not take place, leaving the sidewalls of InAsSb NWs atomically flat.

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