Search

Your search keyword '"Philippe Schieffer"' showing total 22 results
Start Over "Philippe Schieffer" Publication Year Range Last 10 years Language english
22 results on '"Philippe Schieffer"'

1. Epitaxial III–V/Si Vertical Heterostructures with Hybrid 2D‐Semimetal/Semiconductor Ambipolar and Photoactive Properties

Author

Lipin Chen, Yoan Léger, Gabriel Loget, Mekan Piriyev, Imen Jadli, Sylvain Tricot, Tony Rohel, Rozenn Bernard, Alexandre Beck, Julie Le Pouliquen, Pascal Turban, Philippe Schieffer, Christophe Levallois, Bruno Fabre, Laurent Pedesseau, Jacky Even, Nicolas Bertru, and Charles Cornet

Subjects
2D topological semimetal, ambipolar properties, energy harvesting, hybrid heterostructures, III–V/Si, photo‐electro‐chemistry, Science
Abstract

Abstract Hybrid materials taking advantage of the different physical properties of materials are highly attractive for numerous applications in today's science and technology. Here, it is demonstrated that epitaxial bi‐domain III–V/Si are hybrid structures, composed of bulk photo‐active semiconductors with 2D topological semi‐metallic vertical inclusions, endowed with ambipolar properties. By combining structural, transport, and photoelectrochemical characterizations with first‐principle calculations, it is shown that the bi‐domain III–V/Si materials are able within the same layer to absorb light efficiently, separate laterally the photo‐generated carriers, transfer them to semimetal singularities, and ease extraction of both electrons and holes vertically, leading to efficient carrier collection. Besides, the original topological properties of the 2D semi‐metallic inclusions are also discussed. This comb‐like heterostructure not only merges the superior optical properties of semiconductors with good transport properties of metallic materials, but also combines the high efficiency and tunability afforded by III–V inorganic bulk materials with the flexible management of nano‐scale charge carriers usually offered by blends of organic materials. Physical properties of these novel hybrid heterostructures can be of great interest for energy harvesting, photonic, electronic or computing devices.

Published
2022
Full Text
View/download PDF

2. Study of MoS2 Deposited by ALD on c-Si, Towards the Development of MoS2/c-Si Heterojunction Photovoltaics

Author

Bienlo Flora Zerbo, Mircea Modreanu, Ian Povey, Jun Lin, Antoine Létoublon, Alain Rolland, Laurent Pédesseau, Jacky Even, Bruno Lépine, Pascal Turban, Philippe Schieffer, Alain Moréac, and Olivier Durand

Subjects
2D molybdenum disulfide, silicon heterojunctions, solar cells, Crystallography, QD901-999
Abstract

Silicon-based heterojunction (SHJ) solar cells demonstrate high efficiencies over their homojunction counterparts, revealing the potential of such technologies. We present here the first steps towards the development of molybdenum disulfide (MoS2)/c-silicon heterojunction solar cells, consisting of a preliminary study of the MoS2 material and numerical device simulations of MoS2/Si heterojunction solar cells, using SILVACO ATLAS. Through the optical and structural characterization of MoS2/SiO2/Si samples, we found a significant sensitivity of the MoS2 to ambient oxidation. Optical ellipsometry showed a bandgap of 1.87 eV for a 7 monolayer thick MoS2 sample, suitable for the targeted application. Finally, we briefly introduce a device simulation and show that the MoS2/Si heterojunction could lead to a gain in quantum efficiency, especially in the region with short wavelengths, compared with a standard a-Si/c-Si solar cell.

Published
2022
Full Text
View/download PDF

3. Reduction of Schottky Barrier Height at Graphene/Germanium Interface with Surface Passivation

Author

Jules Courtin, Alain Moréac, Gabriel Delhaye, Bruno Lépine, Sylvain Tricot, Pascal Turban, Philippe Schieffer, and Jean-Christophe Le Breton

Subjects
graphene, germanium, schottky, photoemission, surface passivation, Technology, Engineering (General). Civil engineering (General), TA1-2040, Biology (General), QH301-705.5, Physics, QC1-999, Chemistry, QD1-999
Abstract

Fermi level pinning at metal/semiconductor interfaces forbids a total control over the Schottky barrier height. 2D materials may be an interesting route to circumvent this problem. As they weakly interact with their substrate through Van der Waals forces, deposition of 2D materials avoids the formation of the large density of state at the semiconductor interface often responsible for Fermi level pinning. Here, we demonstrate the possibility to alleviate Fermi-level pinning and reduce the Schottky barrier height by the association of surface passivation of germanium with the deposition of 2D graphene.

Published
2019
Full Text
View/download PDF

4. Simple renormalization schemes for multiple scattering series expansions

Author

Aika Takatsu, Sylvain Tricot, Philippe Schieffer, Kevin Dunseath, Mariko Terao-Dunseath, Keisuke Hatada, Didier Sébilleau, University of Toyama, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Grant No. 18K05027, Japan Society for the Promotion of Science, and Grant No. JPMJCR1861, Core Research for Evolutional Science and Technology

Subjects
[PHYS]Physics [physics], [PHYS.PHYS.PHYS-ATOM-PH]Physics [physics]/Physics [physics]/Atomic Physics [physics.atom-ph], General Physics and Astronomy, [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], Physical and Theoretical Chemistry, Quantum dynamics, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Computer Science::Databases, Spectroscopy
Abstract

International audience; A number of renormalization schemes for improving the convergence of multiple scattering series expansions are investigated. Numerical tests on a small Cu(111) cluster demonstrate their effectiveness, for example increasing the rate of convergence by up to a factor 2 or by transforming a divergent series into a convergent one. These techniques can greatly facilitate multiple scattering calculations, especially for spectroscopies such as photoelectron diffraction, Auger electron diffraction, low energy electron diffraction , where an electron propagates with a kinetic energy of hundreds of eV in a cluster of hundreds of atoms.

Published
2022
Full Text
View/download PDF

5. Optical and structural characterization of thin MoS2 layers on SiO2/Si substrates, towards the development of MoS2/Si heterojunction photovoltaics

Author

Laurent Pedesseau, Mircea Modreanu, Philippe Schieffer, Antoine Létoublon, Jacky Even, Bruno Lépine, Pascal Turban, Alain Moréac, Olivier Durand, Bienlo Zerbo, Alain Rolland, Ian M. Povey, Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS), University College Cork (UCC), Institut de Physique de Rennes (IPR), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Materials science, Silicon, Band gap, business.industry, chemistry.chemical_element, Heterojunction, Characterization (materials science), law.invention, chemistry, Photovoltaics, law, Solar cell, Optoelectronics, Crystallite, business, Photonic crystal
Abstract

International audience; In this paper, we present the first steps of a process toward the development of MoS2/Si heterojunctions photovoltaics, using 2D 2H-MoS2, whose natural abundance and tunable bandgap make it suitable for such application. A focus is made here on the optimization of the MoS2 material and its deposition process, through preliminary optical and structural characterizations of thin 2H-MoS2 layers deposited on 80nm SiO2 on top of Si (001) substrates. Our investigations revealed oxidation of the MoS2 layers, and limited longitudinal crystallite size, which may strongly affect the band lineup between MoS2 and Si, and thus, the performance of the solar cell.

Published
2021
Full Text
View/download PDF

6. Epitaxial III–V/Si Vertical Heterostructures with Hybrid 2D‐Semimetal/Semiconductor Ambipolar and Photoactive Properties

Author

Rozenn Bernard, Mekan Piriyev, Gabriel Loget, Nicolas Bertru, Jacky Even, Philippe Schieffer, Lipin Chen, Christophe Levallois, Charles Cornet, Laurent Pedesseau, Imen Jadli, Sylvain Tricot, Bruno Fabre, Pascal Turban, Julie Le Pouliquen, Alexandre Beck, T. Rohel, Yoan Léger, Institut des Fonctions Optiques pour les Technologies de l'informatiON (Institut FOTON), École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), China Scholarship Council. Grant Number: 2017–6254, HPC resources of TGCC/CINES/IDRIS. Grant Numbers: 2020-A0080911434, 2021-A0100911434, Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-IMT Atlantique Bretagne-Pays de la Loire (IMT Atlantique), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)

Subjects
energy harvesting, 2D topological semimetal, Materials science, photo‐electro‐chemistry, Science, General Chemical Engineering, photonics, General Physics and Astronomy, Medicine (miscellaneous), hybrid heterostructures, 02 engineering and technology, 7. Clean energy, 01 natural sciences, Biochemistry, Genetics and Molecular Biology (miscellaneous), photo-electro-chemistry, 0103 physical sciences, General Materials Science, 010306 general physics, Research Articles, ComputingMilieux_MISCELLANEOUS, [PHYS]Physics [physics], III–V/Si, Ambipolar diffusion, business.industry, General Engineering, Heterojunction, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, Semimetal, Semiconductor, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Optoelectronics, ambipolar properties, Charge carrier, Photonics, 0210 nano-technology, business, Hybrid material, Science, technology and society, III-V/Si, Research Article
Abstract

Hybrid materials taking advantage of the different physical properties of materials are highly attractive for numerous applications in today's science and technology. Here, it is demonstrated that epitaxial bi‐domain III–V/Si are hybrid structures, composed of bulk photo‐active semiconductors with 2D topological semi‐metallic vertical inclusions, endowed with ambipolar properties. By combining structural, transport, and photoelectrochemical characterizations with first‐principle calculations, it is shown that the bi‐domain III–V/Si materials are able within the same layer to absorb light efficiently, separate laterally the photo‐generated carriers, transfer them to semimetal singularities, and ease extraction of both electrons and holes vertically, leading to efficient carrier collection. Besides, the original topological properties of the 2D semi‐metallic inclusions are also discussed. This comb‐like heterostructure not only merges the superior optical properties of semiconductors with good transport properties of metallic materials, but also combines the high efficiency and tunability afforded by III–V inorganic bulk materials with the flexible management of nano‐scale charge carriers usually offered by blends of organic materials. Physical properties of these novel hybrid heterostructures can be of great interest for energy harvesting, photonic, electronic or computing devices., Here, it is demonstrated that epitaxial bi‐domain III–V/Si are hybrid structures, composed of bulk photo‐active semiconductors with 2D topological semi metallic vertical inclusions, endowed with ambipolar properties. Operating III–V/Si photoelectrodes confirm that this hybrid material can by itself photogenerate and laterally separate carriers, which are efficiently extracted afterward from the photoelectric device.

Published
2021
Full Text
View/download PDF

7. Origin of weak Fermi level pinning at the graphene/silicon interface

Author

S. Tricot, J. C. Le Breton, B. Lépine, J. Courtin, Philippe Schieffer, Pascal Turban, G. Delhaye, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), ANR-14-CE26-0028-03, Agence Nationale de la Recherche, Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), and ANR-14-CE26-0028,ENSEMBLE,Transport du spin des électrons et communication avec le spin nucléaire dans des structures verticales métal-SiGe-métal fabriqué par collage moléculaire(2014)

Subjects
Materials science, Condensed matter physics, Silicon, Photoemission spectroscopy, Graphene, business.industry, Fermi level, Schottky diode, chemistry.chemical_element, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, law.invention, symbols.namesake, Semiconductor, chemistry, law, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], 0103 physical sciences, symbols, Density functional theory, Work function, 010306 general physics, 0210 nano-technology, business
Abstract

The mechanisms governing the formation of Schottky barriers at graphene/hydrogen-passivated silicon interfaces where the graphene plays the role of a two-dimensional (2D) metal electrode have been investigated by means of x-ray photoemission spectroscopy and density functional theory (DFT) calculations. To control the graphene work function without altering either the structure or the band dispersion of graphene we used a method that consists in depositing small amounts of gold forming clusters on the graphene/hydrogen-passivated silicon system under an ultra-high-vacuum environment. We observe from experimental measurements that the Fermi level is mainly free from pinning at the graphene/hydrogen-silicon interface whereas for a semi-infinite metal on silicon the Fermi level is almost fully pinned. This alleviation of the Fermi level pinning observed with the graphene layer is explained by DFT calculations showing that the graphene and the semiconductor are decoupled and that the metal-induced gap states (MIGS) density at the silicon midgap at the interface is very low ($l5\ifmmode\times\else\texttimes\fi{}{10}^{10}\phantom{\rule{0.16em}{0ex}}\mathrm{states}/(\mathrm{eV}\phantom{\rule{0.28em}{0ex}}\mathrm{c}{\mathrm{m}}^{2})$]. The important conclusion that stems from the DFT results analysis is that the low MIGS density at the semiconductor midgap is related to the 2D nature of the graphene layer. More precisely, the MIGS density is low owing to the lack of propagating states perpendicular to the graphene layer. This finding brings important information to understand the mechanisms that govern the formation and the electronic properties of Schottky barriers at 2D-metal/three-dimensional-semiconductor interfaces.

Published
2020
Full Text
View/download PDF

8. Evidence of Pure Spin-Current Generated by Spin Pumping in Interface-Localized States in Hybrid Metal–Silicon–Metal Vertical Structures

Author

Jian Yin Qin, Xiufeng Han, Jean-Georges Mussot, Xavier Devaux, Henri Jaffrès, Piotr Łaczkowski, Sébastien Petit-Watelot, Zhi Liu, Stéphane Mangin, Yuan Lu, Huong Dang, Bu Wen Cheng, Abdelmadjid Anane, Juan-Carlos Rojas-Sánchez, J.-M. George, Jean-Christophe Le Breton, Abdelhak Djeffal, S. Suire, Carolina Cerqueira, Philippe Schieffer, Mathieu Stoffel, Michel Hehn, Sylvie Migot, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), University of Chinese Academy of Sciences [Beijing] (UCAS), Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), This work is supported by the joint French National Research Agency (ANR)-National Natural Science Foundation of China (NNSFC) ENSEMBLE project (grant nos. ANR-14-CE26-0028-01 and NNSFC 61411136001), Chinese-French International Key Program, National Natural Science Foundation of China (NSFC grant no. 51620105004) and by the French PIA project 'Lorraine Université d’Excellence' (grant no. ANR-15-IDEX-04-LUE). C.C. acknowledges the support from CNPq, National Council for Scientific and Technological Development-Brazil. A.D. acknowledges PhD funding from Region Lorraine., IMPACT N4S, ANR-15-IDEX-0004,LUE,Isite LUE(2015), THALES-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Silicon, Population, chemistry.chemical_element, FOS: Physical sciences, wafer bonding, Bioengineering, 02 engineering and technology, Condensed Matter::Materials Science, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), [CHIM]Chemical Sciences, General Materials Science, inverse spin Hall effect, Spin (physics), education, [PHYS]Physics [physics], Spin pumping, education.field_of_study, Condensed Matter - Materials Science, spin current, Condensed matter physics, Condensed Matter - Mesoscale and Nanoscale Physics, Mechanical Engineering, Materials Science (cond-mat.mtrl-sci), General Chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, localized electronic states, Ferromagnetic resonance, Ferromagnetism, chemistry, Spin Hall effect, Spin diffusion, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology
Abstract

International audience; Due to the difficulty of growing high-quality semiconductors on ferromagnetic metals, the study of spin diffusion transport in Si was limited to lateral geometry devices. In this work, by using an ultrahigh-vacuum wafer-bonding technique, we have successfully fabricated metal–semiconductor–metal CoFeB/MgO/Si/Pt vertical structures. We hereby demonstrate pure spin-current injection and transport in the perpendicular current flow geometry over a distance larger than 2 μm in n-type Si at room temperature. In those experiments, a pure propagating spin current is generated via ferromagnetic resonance spin pumping and converted into a measurable voltage by using the inverse spin Hall effect occurring in the top Pt layer. A systematic study varying both Si and MgO thicknesses reveals the important role played by the localized states at the MgO–Si interface for the spin-current generation. Proximity effects involving indirect exchange interactions between the ferromagnet and the MgO–Si interface states appears to be a prerequisite to establishing the necessary out-of-equilibrium spin population in Si under the spin-pumping action.

Published
2019
Full Text
View/download PDF

9. Reduction of Schottky Barrier Height at Graphene/Germanium Interface with Surface Passivation

Author

Philippe Schieffer, Gabriel Delhaye, Sylvain Tricot, Bruno Lépine, Pascal Turban, Alain Moréac, Jules Courtin, Jean-Christophe Le Breton, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), ANR-18-CE24-0017-01, Agence Nationale de la Recherche, ANR-18-CE24-0017,FEOrgSpin,Contrôle ferroélectrique de la spinterface organique/ferromagnétique(2018), Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Passivation, Schottky barrier, chemistry.chemical_element, Germanium, 02 engineering and technology, Substrate (electronics), 01 natural sciences, lcsh:Technology, law.invention, lcsh:Chemistry, symbols.namesake, law, 0103 physical sciences, General Materials Science, Instrumentation, lcsh:QH301-705.5, surface passivation, 010302 applied physics, Fluid Flow and Transfer Processes, [PHYS]Physics [physics], Condensed matter physics, business.industry, Graphene, lcsh:T, Process Chemistry and Technology, graphene, General Engineering, Schottky diode, Schottky, 021001 nanoscience & nanotechnology, lcsh:QC1-999, Computer Science Applications, [SPI.TRON]Engineering Sciences [physics]/Electronics, germanium, Semiconductor, chemistry, lcsh:Biology (General), lcsh:QD1-999, lcsh:TA1-2040, symbols, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], van der Waals force, 0210 nano-technology, business, lcsh:Engineering (General). Civil engineering (General), lcsh:Physics, photoemission
Abstract

International audience; Fermi level pinning at metal/semiconductor interfaces forbids a total control over the Schottky barrier height. 2D materials may be an interesting route to circumvent this problem. As they weakly interact with their substrate through Van der Waals forces, deposition of 2D materials avoids the formation of the large density of state at the semiconductor interface often responsible for Fermi level pinning. Here, we demonstrate the possibility to alleviate Fermi-level pinning and reduce the Schottky barrier height by the association of surface passivation of germanium with the deposition of 2D graphene

Published
2019
Full Text
View/download PDF

10. Band Alignments in Fe/Graphene/Si(001) Junctions Studied by X-ray Photoemission Spectroscopy

Author

Bruno Lépine, Philippe Schieffer, Gabriel Delhaye, Sylvain Tricot, J. C. Le Breton, Pascal Turban, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), ANR-14-CE26-0028,ENSEMBLE,Transport du spin des électrons et communication avec le spin nucléaire dans des structures verticales métal-SiGe-métal fabriqué par collage moléculaire(2014), ANR-14-0028-01, NSFC, National Natural Science Foundation of China, Le Breton, Jean-Christophe, Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), and Appel à projets générique - Transport du spin des électrons et communication avec le spin nucléaire dans des structures verticales métal-SiGe-métal fabriqué par collage moléculaire - - ENSEMBLE2014 - ANR-14-CE26-0028 - Appel à projets générique - VALID

Subjects
Silicon, Silicides, Physics and Astronomy (miscellaneous), Schottky barrier, Iron, Nanotechnology, 02 engineering and technology, 01 natural sciences, law.invention, Schottky barrier heights, Passivation, Hydrogen passivation, law, Semiconductor devices, 0103 physical sciences, Semiconductor doping, 010306 general physics, Doping concentration, ComputingMilieux_MISCELLANEOUS, Graphene oxide paper, Elevated temperature, X ray photoemission spectroscopy, [PHYS]Physics [physics], Substrates, Graphene, business.industry, Doping, Magnetic dead layers, Heterojunction, Interface states, 021001 nanoscience & nanotechnology, Semimetal, [PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Photoelectron spectroscopy, Semiconductor, Semiconducting silicon, Interface chemistry, Heterojunctions, Magnetoelectronics, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Optoelectronics, Schottky barrier diodes, 0210 nano-technology, business, Spintronic device, Graphene nanoribbons
Abstract

International audience; The control of tunnel contact resistance is of primary importance for semiconductor-based spintronic devices. This control is hardly achieved with conventional oxide-based tunnel barriers due to deposition-induced interface states. Manipulation of single 2D atomic crystals (such as graphene sheets) weakly interacting with their substrate might represent an alternative and efficient way to design new heterostructures for a variety of different purposes including spin injection into semiconductors. In the present paper, we study by x-ray photoemission spectroscopy the band alignments and interface chemistry of iron-graphene-hydrogenated passivated silicon (001) surfaces for a low and a high n-doping concentration. We find that the hydrogen passivation of the Si(001) surface remains efficient even with a graphene sheet on the Si(001) surface. For both doping concentrations, the semiconductor is close to flat-band conditions which indicates that the Fermi level is unpinned on the semiconductor side of the Graphene/Si(001):H interface. When iron is deposited on the graphene/Si(001):H structures, the Schottky barrier height remains mainly unaffected by the metallic overlayer with a very low barrier height for electrons, a sought-after property in semiconductor based spintronic devices. Finally, we demonstrate that the graphene layer intercalated between the metal and semiconductor also serves as a protection against iron-silicide formation even at elevated temperatures preventing from the formation of a Si-based magnetic dead layer. © 2016 Author(s).

Published
2017
Full Text
View/download PDF

11. Effective Metal Top Contact on the Organic Layer via Buffer-Layer-Assisted Growth: A Multiscale Characterization of Au/Hexadecanethiol/n-GaAs(100) Junctions

Author

Arnaud Le Pottier, Francine Solal, Sylvain Tricot, Soraya Ababou-Girard, Pascal Turban, Alexandra Junay, Sophie Guézo, Philippe Schieffer, José Avila, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), FEDER, Federación Española de Enfermedades Raras, and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Multiscale characterizations, Materials science, Ballistic electron emission microscopy, Transport measurements, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Electron transport properties, Organic monolayers, Metal, Electron emission, Hot-electron transport, Monolayer, Buffer layers, Physical and Theoretical Chemistry, Nanoscopic scale, Spatial uniformity, Buffer-layer-assisted growth, Monolayers, [PHYS]Physics [physics], business.industry, Monolayer coverage, Molecular electronics, Heterojunction, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Characterization (materials science), General Energy, Metals, visual_art, visual_art.visual_art_medium, Optoelectronics, Gold, 0210 nano-technology, business, Layer (electronics)
Abstract

International audience; In the field of organic and molecular electronics at monolayer coverage, the need for abrupt and well-controlled top metal contacts is a key point. A general method which provides reliable molecular junctions with most metals remains to be found. In this paper we show that reliable molecular junctions Au/hexadecanethiol/n-GaAs(100) are obtained using buffer-layer-assisted growth (BLAG). They show in hot electron transport measurements at the nanoscale a tunnel regime through the organic monolayer with a full spatial uniformity. Using ballistic electron emission microscopy (BEEM) in the spectroscopic mode as well as photoemission and C(V)-transport measurements, we draw a coherent band alignment scheme of the whole heterostructure at the nanoscale and at the macroscopic scale. Through this study, the BLAG method appears as a general method that should work for contacting organic monolayers with most metals. © 2016 American Chemical Society.

Published
2016
Full Text
View/download PDF

12. Electric field effect on magnetic properties of ferromagnetic/SrTiO3(001) interfaces

Author

Mordret, Julien, Viel, Alexandra, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], PhDtitle, [PHYS] Physics [physics]
Abstract

supervisors Philippe Schieffer and Sylvain Tricot (department of materials - nanosciences), sous la direction de Philippe Schieffer et de Sylvain Tricot dans le département Matériaux-Nanosciences

Published
2021

13. Study of MoS 2 Deposited by ALD on c-Si, Towards the Development of MoS 2 /c-Si Heterojunction Photovoltaics.

Author

Zerbo, Bienlo Flora, Modreanu, Mircea, Povey, Ian, Lin, Jun, Létoublon, Antoine, Rolland, Alain, Pédesseau, Laurent, Even, Jacky, Lépine, Bruno, Turban, Pascal, Schieffer, Philippe, Moréac, Alain, and Durand, Olivier

Subjects
SOLAR cells, HETEROJUNCTIONS, PHOTOVOLTAIC power generation, PHOTOVOLTAIC power systems, QUANTUM efficiency, MOLYBDENUM disulfide, ELLIPSOMETRY
Abstract

Silicon-based heterojunction (SHJ) solar cells demonstrate high efficiencies over their homojunction counterparts, revealing the potential of such technologies. We present here the first steps towards the development of molybdenum disulfide (MoS2)/c-silicon heterojunction solar cells, consisting of a preliminary study of the MoS2 material and numerical device simulations of MoS2/Si heterojunction solar cells, using SILVACO ATLAS. Through the optical and structural characterization of MoS2/SiO2/Si samples, we found a significant sensitivity of the MoS2 to ambient oxidation. Optical ellipsometry showed a bandgap of 1.87 eV for a 7 monolayer thick MoS2 sample, suitable for the targeted application. Finally, we briefly introduce a device simulation and show that the MoS2/Si heterojunction could lead to a gain in quantum efficiency, especially in the region with short wavelengths, compared with a standard a-Si/c-Si solar cell. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

15. Simple renormalization schemes for multiple scattering series expansions.

Author

Takatsu, Aika, Tricot, Sylvain, Schieffer, Philippe, Dunseath, Kevin, Terao-Dunseath, Mariko, Hatada, Keisuke, and Sébilleau, Didier

Abstract

A number of renormalization schemes for improving the convergence of multiple scattering series expansions are investigated. Numerical tests on a small Cu(111) cluster demonstrate their effectiveness, for example increasing the rate of convergence by up to a factor 2 or by transforming a divergent series into a convergent one. These techniques can greatly facilitate multiple scattering calculations, especially for spectroscopies such as photoelectron diffraction, Auger electron diffraction, low energy electron diffraction etc., where an electron propagates with a kinetic energy of hundreds of eV in a cluster of hundreds of atoms. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

16. Epitaxial III–V/Si Vertical Heterostructures with Hybrid 2D‐Semimetal/Semiconductor Ambipolar and Photoactive Properties.

Author

Chen, Lipin, Léger, Yoan, Loget, Gabriel, Piriyev, Mekan, Jadli, Imen, Tricot, Sylvain, Rohel, Tony, Bernard, Rozenn, Beck, Alexandre, Le Pouliquen, Julie, Turban, Pascal, Schieffer, Philippe, Levallois, Christophe, Fabre, Bruno, Pedesseau, Laurent, Even, Jacky, Bertru, Nicolas, and Cornet, Charles

Subjects
HETEROSTRUCTURES, CHARGE carriers, MECHANICAL properties of condensed matter, MATERIALS management, TOPOLOGICAL property, ENERGY harvesting, HETEROJUNCTIONS, PHOTOCATHODES
Abstract

Hybrid materials taking advantage of the different physical properties of materials are highly attractive for numerous applications in today's science and technology. Here, it is demonstrated that epitaxial bi‐domain III–V/Si are hybrid structures, composed of bulk photo‐active semiconductors with 2D topological semi‐metallic vertical inclusions, endowed with ambipolar properties. By combining structural, transport, and photoelectrochemical characterizations with first‐principle calculations, it is shown that the bi‐domain III–V/Si materials are able within the same layer to absorb light efficiently, separate laterally the photo‐generated carriers, transfer them to semimetal singularities, and ease extraction of both electrons and holes vertically, leading to efficient carrier collection. Besides, the original topological properties of the 2D semi‐metallic inclusions are also discussed. This comb‐like heterostructure not only merges the superior optical properties of semiconductors with good transport properties of metallic materials, but also combines the high efficiency and tunability afforded by III–V inorganic bulk materials with the flexible management of nano‐scale charge carriers usually offered by blends of organic materials. Physical properties of these novel hybrid heterostructures can be of great interest for energy harvesting, photonic, electronic or computing devices. [ABSTRACT FROM AUTHOR]

Published
2022
Full Text
View/download PDF

17. PhD in progress : Ingénierie d'interface du silicium par des matériaux 2D [Defense 14.12.2020]

Author

Jules, Courtin, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Viel, Alexandra, and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], PhDtitle, Soutenance2020, [PHYS] Physics [physics]
Abstract

supervisor Philippe Schieffer department of materials - nanosciences), sous la direction de Philippe Schieffer dans le département Matériaux-Nanosciences

Published
2017

18. PhD in progress :Caractérisations avancées des propriétés électroniques et structurales de matériaux III - V intégrés sur silicium [Defense : cancelled]

Author

Charbonnier, Simon, Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics]
Abstract

supervisors Pascal Turban and Philippe Schieffer (department of materials - nanosciences); sous la direction de Pascal Turban et de Philippe Schieffer dans le département Matériaux-Nanosciences

Published
2015

19. Formation de l'interface Fe/SrTiO₃(001) : propriétés électroniques et structurales [Defense 26.11.2018]

Author

Catrou, Pierre, Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), and Viel, Alexandra

Subjects
[PHYS]Physics [physics], PhDtitle, Soutenance2018, [PHYS] Physics [physics]
Abstract

supervisor Philippe Schieffer (department of soft matter), sous la direction de Philippe Schieffer dans le département matière molle

Published
2015

20. Reduction of Schottky Barrier Height at Graphene/Germanium Interface with Surface Passivation.

Author

Courtin, Jules, Moréac, Alain, Delhaye, Gabriel, Lépine, Bruno, Tricot, Sylvain, Turban, Pascal, Schieffer, Philippe, and Le Breton, Jean-Christophe

Subjects
SURFACE passivation, SCHOTTKY barrier, PASSIVATION, SEMICONDUCTOR junctions, VAN der Waals forces, GERMANIUM, SEMIMETALS
Abstract

Fermi level pinning at metal/semiconductor interfaces forbids a total control over the Schottky barrier height. 2D materials may be an interesting route to circumvent this problem. As they weakly interact with their substrate through Van der Waals forces, deposition of 2D materials avoids the formation of the large density of state at the semiconductor interface often responsible for Fermi level pinning. Here, we demonstrate the possibility to alleviate Fermi-level pinning and reduce the Schottky barrier height by the association of surface passivation of germanium with the deposition of 2D graphene. [ABSTRACT FROM AUTHOR]

Published
2019
Full Text
View/download PDF

21. University of Rennes Reports Findings in Science (Epitaxial III-V/Si Vertical Heterostructures with Hybrid 2D-Semimetal/Semiconductor Ambipolar and Photoactive Properties)

Subjects
Epitaxy -- Reports -- Research, Electronics industry -- Research -- Reports, Electronics industry, Electronics
Abstract

2021 NOV 23 (VerticalNews) -- By a News Reporter-Staff News Editor at Electronics Newsweekly -- New research on Science is the subject of a report. According to news originating from [...]

Published
2021

Catalog

Books, media, physical & digital resources
See catalog results