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87 results on '"Stéphane Berciaud"'

1. Dynamically-enhanced strain in atomically thin resonators

Author

Xin Zhang, Kevin Makles, Léo Colombier, Dominik Metten, Hicham Majjad, Pierre Verlot, and Stéphane Berciaud

Subjects
Science
Abstract

Here, the authors use Raman spectroscopy on circular graphene drums to demonstrate dynamical softening of optical phonons induced by the macroscopic flexural motion of graphene, and find evidence that the strain in graphene is enhanced under non-linear driving.

Published
2020
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2. Charge Versus Energy Transfer in Atomically Thin Graphene-Transition Metal Dichalcogenide van der Waals Heterostructures

Author

Guillaume Froehlicher, Etienne Lorchat, and Stéphane Berciaud

Subjects
Physics, QC1-999
Abstract

Made from stacks of two-dimensional materials, van der Waals heterostructures exhibit unique light-matter interactions and are promising for novel optoelectronic devices. The performance of such devices is governed by near-field coupling through, e.g., interlayer charge and/or energy transfer. New concepts and experimental methodologies are needed to properly describe two-dimensional heterointerfaces. Here, we report an original study of interlayer charge and energy transfer in atomically thin metal-semiconductor [i.e., graphene-transition metal dichalcogenide (TMD, here molybdenum diselenide, MoSe_{2})] heterostructures using a combination of microphotoluminescence and Raman scattering spectroscopies. The photoluminescence intensity in graphene/MoSe_{2} is quenched by more than 2 orders of magnitude and rises linearly with the incident photon flux, demonstrating a drastically shortened (about 1 ps) room-temperature MoSe_{2} exciton lifetime. Key complementary insights are provided from a comprehensive analysis of the graphene and MoSe_{2} Raman modes, which reveals net photoinduced electron transfer from MoSe_{2} to graphene and hole accumulation in MoSe_{2}. Remarkably, the steady-state Fermi energy of graphene saturates at 290±15 meV above the Dirac point. This reproducible behavior is observed both in ambient air and in vacuum and is discussed in terms of intrinsic factors (i.e., band offsets) and environmental effects. In this saturation regime, balanced photoinduced flows of electrons and holes may transfer to graphene, a mechanism that effectively leads to energy transfer. Using a broad range of incident photon fluxes and diverse environmental conditions, we find that the presence of net photoinduced charge transfer has no measurable impact on the near-unity photoluminescence quenching efficiency in graphene/MoSe_{2}. This absence of correlation strongly suggests that energy transfer to graphene (either in the form of electron exchange or dipole-dipole interaction) is the dominant interlayer coupling mechanism between atomically thin TMDs and graphene.

Published
2018
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3. Tip-Induced and Electrical Control of the Photoluminescence Yield of Monolayer WS2

Author

Ricardo Javier Peña Román, Rémi Bretel, Delphine Pommier, Luis Enrique Parra López, Etienne Lorchat, Elizabeth Boer-Duchemin, Gérald Dujardin, Andrei G. Borisov, Luiz Fernando Zagonel, Guillaume Schull, Stéphane Berciaud, Eric Le Moal, Instituto de Fisica 'Gleb Wataghin' (INSTITUTO DE FISICA 'GLEB WATAGHIN'), Universidade Estadual de Campinas = University of Campinas (UNICAMP), Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Physics & Informatics Laboratories, NTT Research, Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) projects 18/08543-7, 20/12480-0, 14/23399-9., ANR-15-CE24-0016,H2DH,Hétérostructures bi-dimendionnelles hybrides pour l'optoélectronique(2015), ANR-15-CE24-0020,INTELPLAN,Une nanosource de plasmons électrique et intégrée(2015), ANR-16-CE24-0003,M-Exc-ICO,Excitonique moléculaire pour l'optoélectronique cohérente intégrée(2016), ANR-20-CE24-0010,ATOEMS,Dispositifs opto-electro-mécaniques d'épaisseur atomique(2020), ANR-11-LABX-0058,NIE,Nanostructures en Interaction avec leur Environnement(2011), ANR-10-LABX-0035,Nano-Saclay,Paris-Saclay multidisciplinary Nano-Lab(2010), ANR-10-IDEX-0002,UNISTRA,Par-delà les frontières, l'Université de Strasbourg(2010), ANR-20-SFRI-0012,STRAT'US,Façonner les talents en formation et en recherche à l'Université de Strasbourg(2020), ANR-17-EURE-0024,QMAT,Quantum Science and Nanomaterials(2017), and European Project: 771850,APOGEE

Subjects
exciton, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Mechanical Engineering, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], scanning tunneling microscopy, General Materials Science, Bioengineering, nano-optics, General Chemistry, 2D materials, Condensed Matter Physics
Abstract

International audience; The photoluminescence (PL) of monolayer tungsten disulfide (WS2) is locally and electrically controlled using the nonplasmonic tip and tunneling current of a scanning tunneling microscope (STM). The spatial and spectral distribution of the emitted light is determined using an optical microscope. When the STM tip is engaged, short-range PL quenching due to near-field electromagnetic effects is present, independent of the sign and value of the bias voltage applied to the tip–sample tunneling junction. In addition, a bias-voltage-dependent long-range PL quenching is measured when the sample is positively biased. We explain these observations by considering the native n-doping of monolayer WS2 and the charge carrier density gradients induced by electron tunneling in micrometer-scale areas around the tip position. The combination of wide-field PL microscopy and charge carrier injection using an STM opens up new ways to explore the interplay between excitons and charge carriers in two-dimensional semiconductors.

Published
2022
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4. Single- and narrow-line photoluminescence in a boron nitride-supported MoSe 2 /graphene heterostructure

Author

Loïc Moczko, Aditya Singh, Michelangelo Romeo, Etienne Lorchat, Joanna Wolff, Kenji Watanabe, Luis E. Parra López, Stéphane Berciaud, and Takashi Taniguchi

Subjects
Materials science, Photoluminescence, Exciton, FOS: Physical sciences, General Physics and Astronomy, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, law.invention, Condensed Matter::Materials Science, chemistry.chemical_compound, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Monolayer, 010306 general physics, Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, Graphene, Doping, Materials Science (cond-mat.mtrl-sci), Heterojunction, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 3. Good health, chemistry, Boron nitride, Optoelectronics, business, Bilayer graphene
Abstract

Heterostructures made from van der Waals materials provide a template to investigate proximity effects at atomically sharp heterointerfaces. In particular, near-field charge and energy transfer in heterostructures made from semiconducting transition metal dichalcogenides (TMD) have attracted interest to design model 2D "donor-acceptor" systems and new optoelectronic components. Here, using of Raman scattering and photoluminescence spectroscopies, we report a comprehensive characterization of a molybedenum diselenide (MoSe$_2$) monolayer deposited onto hexagonal boron nitride (hBN) and capped by mono- and bilayer graphene. Along with the atomically flat hBN susbstrate, a single graphene epilayer is sufficient to passivate the MoSe$_2$ layer and provides a homogenous environment without the need for an extra capping layer. As a result, we do not observe photo-induced doping in our heterostructure and the MoSe$_2$ excitonic linewidth gets as narrow as 1.6~meV, hence approaching the homogeneous limit. The semi-metallic graphene layer neutralizes the 2D semiconductor and enables picosecond non-radiative energy transfer that quenches radiative recombination from long-lived states. Hence, emission from the neutral band edge exciton largely dominates the photoluminescence spectrum of the MoSe$_2$/graphene heterostructure. Since this exciton has a picosecond radiative lifetime at low temperature, comparable with the energy transfer time, its low-temperature photoluminescence is only quenched by a factor of $3.3 \pm 1$ and $4.4 \pm 1$ in the presence of mono- and bilayer graphene, respectively. Finally, while our bare MoSe$_2$ on hBN exhibits negligible valley polarization at low temperature and under near-resonant excitation, we show that interfacing MoSe$_2$ with graphene yields a single-line emitter with degrees of valley polarization and coherence up to $\sim 15\,\%$., version 3, 5 figures

Published
2022
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6. Tip-induced excitonic luminescence nanoscopy of an atomically-resolved van der Waals heterostructure

Author

Luis E. Parra López, Anna Rosławska, Fabrice Scheurer, Stéphane Berciaud, and Guillaume Schull

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Mechanical Engineering, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, General Chemistry, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Condensed Matter::Materials Science, Mechanics of Materials, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Physics::Atomic and Molecular Clusters, General Materials Science, Optics (physics.optics), Physics - Optics
Abstract

Low-temperature scanning tunneling microscopy is used to probe, with atomic-scale spatial resolution, the intrinsic luminescence of a van der Waals heterostructure, made of a transition metal dichalcogenide monolayer stacked onto a few-layer graphene flake supported by an Au(111) substrate. Sharp emission lines arising from neutral, charged and localised excitons are reported. Their intensities and emission energies vary as a function of the nanoscale environment of the van der Waals heterostructure, explaining the variability of the emission properties observed with diffraction-limited approaches. Our work paves the way towards understanding and control of optoelectronic phenomena in moir\'e superlattices with atomic-scale resolution., Comment: 14 pages, 4 figures, 3 supplementary figures

Published
2022

7. Dynamically-enhanced strain in atomically thin resonators

Author

Léo Colombier, Pierre Verlot, Stéphane Berciaud, Xin Zhang, Dominik Metten, Hicham Majjad, Kevin Makles, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), and Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Phonon, Science, FOS: Physical sciences, General Physics and Astronomy, Physics::Optics, 02 engineering and technology, Two-dimensional materials, 01 natural sciences, General Biochemistry, Genetics and Molecular Biology, Article, law.invention, Root mean square, NEMS, symbols.namesake, Condensed Matter::Materials Science, Strain engineering, Flexural strength, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Physics::Atomic and Molecular Clusters, Physics::Chemical Physics, 010306 general physics, lcsh:Science, Softening, Condensed Matter - Materials Science, Multidisciplinary, Condensed matter physics, [PHYS.PHYS]Physics [physics]/Physics [physics], Condensed Matter - Mesoscale and Nanoscale Physics, Graphene, Condensed Matter::Other, Materials Science (cond-mat.mtrl-sci), Heterojunction, General Chemistry, 021001 nanoscience & nanotechnology, Optical properties and devices, symbols, lcsh:Q, Electronic properties and devices, 0210 nano-technology, Raman spectroscopy, Mechanical and structural properties and devices
Abstract

Graphene and related two-dimensional (2D) materials associate remarkable mechanical, electronic, optical and phononic properties. As such, 2D materials are promising for hybrid systems that couple their elementary excitations (excitons, phonons) to their macroscopic mechanical modes. These built-in systems may yield enhanced strain-mediated coupling compared to bulkier architectures, e.g., comprising a single quantum emitter coupled to a nano-mechanical resonator. Here, using micro-Raman spectroscopy on pristine monolayer graphene drums, we demonstrate that the macroscopic flexural vibrations of graphene induce dynamical optical phonon softening. This softening is an unambiguous fingerprint of dynamically-induced tensile strain that reaches values up to $\mathbf{\approx 4 \times 10^{-4}}$ under strong non-linear driving. Such non-linearly enhanced strain exceeds the values predicted for harmonic vibrations with the same root mean square (RMS) amplitude by more than one order of magnitude. Our work holds promise for dynamical strain engineering and dynamical strain-mediated control of light-matter interactions in 2D materials and related heterostructures., Main manuscript (figures 1 to 4) and SI file (supplementary figures S1 to S22; supplementary sections S1 to S11)

Published
2020
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8. Picosecond energy transfer in a transition metal dichalcogenide-graphene heterostructure revealed by transient Raman spectroscopy

Author

Carino Ferrante, Giorgio Di Battista, Luis E. Parra López, Giovanni Batignani, Etienne Lorchat, Alessandra Virga, Stéphane Berciaud, and Tullio Scopigno

Subjects
Raman scattering, Condensed Matter - Materials Science, energy transfer, Multidisciplinary, Condensed Matter - Mesoscale and Nanoscale Physics, graphene, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, ultrafast spectroscopy, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), van der Waals heterostructures, Physics - Optics, Optics (physics.optics)
Abstract

Intense light-matter interactions and unique structural and electrical properties make Van der Waals heterostructures composed by Graphene (Gr) and monolayer transition metal dichalcogenides (TMD) promising building blocks for tunnelling transistors, flexible electronics, as well as optoelectronic devices, including photodetectors, photovoltaics and quantum light emitting devices (QLEDs), bright and narrow-line emitters using minimal amounts of active absorber material. The performance of such devices is critically ruled by interlayer interactions which are still poorly understood in many respects. Specifically, two classes of coupling mechanisms have been proposed: charge transfer (CT) and energy transfer (ET), but their relative efficiency and the underlying physics is an open question. Here, building on a time resolved Raman scattering experiment, we determine the electronic temperature profile of Gr in response to TMD photo-excitation, tracking the picosecond dynamics of the G and 2D bands. Compelling evidence for a dominant role ET process accomplished within a characteristic time of ~ 4 ps is provided. Our results suggest the existence of an intermediate process between the observed picosecond ET and the generation of a net charge underlying the slower electric signals detected in optoelectronic applications., Comment: 32 pages, 15 figures

Published
2022

9. 0D/2D Heterostructures Vertical Single Electron Transistor

Author

L. Simon, Ulrich Nguétchuissi Noumbé, Louis Donald Notemgnou Mouafo, Walid Baaziz, Florian Godel, Bernard Doudin, Ovidiu Ersen, Pierre Seneor, Marie-Blandine Martin, Stéphane Berciaud, Bruno Dlubak, Etienne Lorchat, Jean-Francois Dayen, Yannick J. Dappe, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES-Centre National de la Recherche Scientifique (CNRS), Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de chimie et procédés pour l'énergie, l'environnement et la santé (ICPEES), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Institut de Science des Matériaux de Mulhouse (IS2M), Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Laboratoire des Matériaux, Surfaces et Procédés pour la Catalyse (LMSPC), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), ANR-19-CE09-0028,MIXES,Hétérostructures de van der Waals à dimensions mixtes pour l'électronique et la spintronique(2019), ANR-19-CE24-0022,COPIN,Détecteur plasmonique à nanoCristaux colloïdaux: une nouvelle filière pour l'OPtoélectronique INfrarouge(2019), ANR-19-CE24-0015,STEM2D,Emetteurs THz de type synchrotron à base de matériaux 2D ondulés(2019), ANR-19-GRF1-0001,SOgraphMEM,Spin Orbit functionalized GRAPHene for resistive-magnetic MEMories(2019), ANR-11-LABX-0058,NIE,Nanostructures en Interaction avec leur Environnement(2011), ANR-10-LABX-0035,Nano-Saclay,Paris-Saclay multidisciplinary Nano-Lab(2010), ANR-10-IDEX-0002,UNISTRA,Par-delà les frontières, l'Université de Strasbourg(2010), univOAK, Archive ouverte, Hétérostructures de van der Waals à dimensions mixtes pour l'électronique et la spintronique - - MIXES2019 - ANR-19-CE09-0028 - AAPG2019 - VALID, Détecteur plasmonique à nanoCristaux colloïdaux: une nouvelle filière pour l'OPtoélectronique INfrarouge - - COPIN2019 - ANR-19-CE24-0022 - AAPG2019 - VALID, Emetteurs THz de type synchrotron à base de matériaux 2D ondulés - - STEM2D2019 - ANR-19-CE24-0015 - AAPG2019 - VALID, Spin Orbit functionalized GRAPHene for resistive-magnetic MEMories - - SOgraphMEM2019 - ANR-19-GRF1-0001 - FLAG-ERA JTC 2019 - VALID, Nanostructures en Interaction avec leur Environnement - - NIE2011 - ANR-11-LABX-0058 - LABX - VALID, Paris-Saclay multidisciplinary Nano-Lab - - Nano-Saclay2010 - ANR-10-LABX-0035 - LABX - VALID, Initiative d'excellence - Par-delà les frontières, l'Université de Strasbourg - - UNISTRA2010 - ANR-10-IDEX-0002 - IDEX - VALID, Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE)

Subjects
Materials science, 2D heterostructures, single electron transistors, [SPI.NANO] Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Nanoclusters, Biomaterials, nanoelectronics, Condensed Matter::Materials Science, Electric field, Electrochemistry, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, ComputingMilieux_MISCELLANEOUS, [PHYS]Physics [physics], Spintronics, business.industry, Electric potential energy, transition metal dichalcogenides, Coulomb blockade, Heterojunction, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Nanoelectronics, Quantum dot, Optoelectronics, nanoparticles, multifunctional materials, 0210 nano-technology, business, [PHYS.COND] Physics [physics]/Condensed Matter [cond-mat]
Abstract

Mixed-dimensional heterostructures formed by the stacking of 2D materials with nanostructures of distinct dimensionality constitute a new class of nanomaterials that offers multifunctionality that goes beyond those of single dimensional systems. An unexplored architecture of single electron transistor (SET) is developed that employs heterostructures made of nanoclusters (0D) grown on a 2D molybdenum disulfide (MoS2) channel. Combining the large Coulomb energy of the nanoclusters with the electronic capabilities of the 2D layer, the concept of 0D–2D vertical SET is unveiled. The MoS2 underneath serves both as a charge tunable channel interconnecting the electrode, and as bottom electrode for each v-SET cell. In addition, its atomic thickness makes it thinner than the Debye screening length, providing electric field transparency functionality that allows for an efficient electric back gate control of the nanoclusters charge state. The Coulomb diamond pattern characteristics of SET are reported, with specific doping dependent nonlinear features arising from the 0D/2D geometry that are elucidated by theoretical modeling. These results hold promise for multifunctional single electron device taking advantage of the versatility of the 2D materials library, with as example envisioned spintronics applications while coupling quantum dots to magnetic 2D material, or to ferroelectric layers for neuromorphic devices.

Published
2021
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10. Electrical read-out of light-induced spin transition in thin film spin crossover/graphene heterostructures

Author

Aditya Singh, Arnaud Brosseau, Talal Mallah, Nikita Konstantinov, Ulrich Nguétchuissi Noumbé, Bohdan Kundys, Bernard Doudin, Hicham Majjad, Marie-Laure Boillot, Jean-Francois Dayen, Stéphane Berciaud, Marc Lenertz, Arthur Tauzin, Diana Dragoe, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Institut de Chimie du CNRS (INC)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Ecole Normale Supérieure Paris-Saclay (ENS Paris Saclay), Indian Institute of Technology Delhi (IIT Delhi), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Boillot, Marie-Laure, Hétérostructures de van der Waals à dimensions mixtes pour l'électronique et la spintronique - - MIXES2019 - ANR-19-CE09-0028 - AAPG2019 - VALID, Détecteur plasmonique à nanoCristaux colloïdaux: une nouvelle filière pour l'OPtoélectronique INfrarouge - - COPIN2019 - ANR-19-CE24-0022 - AAPG2019 - VALID, Nanostructures en Interaction avec leur Environnement - - NIE2011 - ANR-11-LABX-0058 - LABX - VALID, Initiative d'excellence - Par-delà les frontières, l'Université de Strasbourg - - UNISTRA2010 - ANR-10-IDEX-0002 - IDEX - VALID, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), ANR-19-CE09-0028,MIXES,Hétérostructures de van der Waals à dimensions mixtes pour l'électronique et la spintronique(2019), ANR-19-CE24-0022,COPIN,Détecteur plasmonique à nanoCristaux colloïdaux: une nouvelle filière pour l'OPtoélectronique INfrarouge(2019), ANR-11-LABX-0058,NIE,Nanostructures en Interaction avec leur Environnement(2011), and ANR-10-IDEX-0002,UNISTRA,Par-delà les frontières, l'Université de Strasbourg(2010)

Subjects
Materials science, Spin states, [SPI.NANO] Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, Aucun, Spin transition, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, LIESST, law.invention, nanoelectronics, spin crossover, law, Spin crossover, Molecular film, Materials Chemistry, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, molecular switches, [CHIM.MATE] Chemical Sciences/Material chemistry, Spintronics, business.industry, Graphene, graphene, optical device, Molecular electronics, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Optoelectronics, 0210 nano-technology, business
Abstract

International audience; Magneto-opto-electronic properties are shown for a hybrid device constructed from a spin crossover (SCO) thin film of a Fe[HB(3,5-(Me)2Pz)3]2 molecular material evaporated over a graphene sensing layer. The principle of electrical detection of the light-induced spin transition in SCO/graphene heterostructures is demonstrated. The switchable spin state of the molecular film is translated into a change of conductance of the graphene channel. The low temperature write/erase process of the conductive remnant states is implemented using two distinct excitation wavelengths, in the red (light-induced spin state trapping, LIESST) region for stabilizing the metastable paramagnetic state, and in the near infrared (reverse-LIESST) region for retrieving the stable diamagnetic state. The bistability of the system is confirmed over a significant temperature window through light-induced thermal hysteresis (LITH). This opens new avenues to study the light-induced spin transition mechanisms exploring the coupling mechanisms between SCO systems and 2D materials, providing electrical readings of the molecules/2D substrate interfaces. These results demonstrate how the electronic states of insulating molecular switches can be stored, read and manipulated by multiple stimuli, while transducing them into low impedance signals, thanks to two-dimensional detectors, revealing the full potential of mixed-dimensional heterostructures for molecular electronics and spintronics.

Published
2021
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11. Inelastic tunneling-induced luminescence of excitons in monolayer MoSe2 and WS2

Author

Delphine Pommier, Rémi Bretel, Luis Parra López, Elizabeth Boer-Duchemin, Gérald Dujardin, Guillaume Schull, Stéphane Berciaud, Eric Le Moal, Nanophysique et Surfaces, Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Le Moal, Eric, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-OPTICS] Physics [physics]/Physics [physics]/Optics [physics.optics], [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], [SPI.OPTI] Engineering Sciences [physics]/Optics / Photonic, [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2020

12. Filtering the photoluminescence spectra of atomically thin semiconductors with graphene

Author

Delphine Lagarde, Takashi Taniguchi, Etienne Lorchat, Xavier Marie, Cedric Robert, Kenji Watanabe, Stéphane Berciaud, Guillaume Froehlicher, Luis E. Parra López, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Optoélectronique Quantique (LPCNO), Laboratoire de physique et chimie des nano-objets (LPCNO), 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 de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), ANR-17-CE24-0001,VallEx,Ingénierie des propriétés excitoniques, de spin et de vallée dans les hétérostructures de van der Waals(2017), ANR-17-EURE-0009,NanoX,Science et Ingénierie à l'Echelle Nano(2017), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)

Subjects
Photoluminescence, Exciton, Biomedical Engineering, Nanophotonics, FOS: Physical sciences, Bioengineering, 02 engineering and technology, Electroluminescence, 010402 general chemistry, 7. Clean energy, 01 natural sciences, law.invention, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Monolayer, General Materials Science, Electrical and Electronic Engineering, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Physics, Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, Graphene, Materials Science (cond-mat.mtrl-sci), Heterojunction, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, Semiconductor, Optoelectronics, 0210 nano-technology, business, Optics (physics.optics), Physics - Optics
Abstract

Atomically thin semiconductors made from transition metal dichalcogenides (TMDs) are model systems for investigations of strong light-matter interactions and applications in nanophotonics, opto-electronics and valley-tronics. However, the photoluminescence spectra of TMD monolayers display a large number of features that are particularly challenging to decipher. On a practical level, monochromatic TMD-based emitters would be beneficial for low-dimensional devices but this challenge is yet to be resolved. Here, we show that graphene, directly stacked onto TMD monolayers enables single and narrow-line photoluminescence arising solely from TMD neutral excitons. This filtering effect stems from complete neutralization of the TMD by graphene combined with selective non-radiative transfer of long-lived excitonic species to graphene. Our approach is applied to four tungsten and molybdenum-based TMDs and establishes TMD/graphene heterostructures as a unique set of opto-electronic building blocks, suitable for electroluminescent systems emitting visible and near-infrared photons at near THz rate with linewidths approaching the lifetime limit., Main manuscript with 5 figures plus supplementary information file (including 9 supplementary sections and 14 supplementary figures)

Published
2020
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13. Many‐Body Effects in Suspended Graphene Probed through Magneto‐Phonon Resonances

Author

Stéphane Berciaud, Clément Faugeras, Marek Potemski, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G ), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Faugeras, Clement, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010302 applied physics, Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Phonon, Graphene, Bilayer, FOS: Physical sciences, Landau quantization, Condensed Matter Physics, 01 natural sciences, Molecular physics, Many body, 3. Good health, law.invention, [PHYS.COND.CM-MSQHE] Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], law, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Materials Science, Graphite, Spectroscopy, Magneto, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]
Abstract

We make use of micro-magneto Raman scattering spectroscopy to probe magneto-phonon resonances (MPR) in suspended mono- to penta-layer graphene. MPR correspond to avoided crossings between zone-center optical phonons (G-mode) and optically-active inter Landau level (LL) transitions and provide a tool to perform LL spectroscopy at a fixed energy ($\approx 197~\rm{meV}$) set by the G-mode phonon. Using a single-particle effective bilayer model, we readily extract the velocity parameter associated with each MPR. A single velocity parameter slightly above the bulk graphite value suffices to fit all MPR for $N\geq2$ layer systems. In contrast, in monolayer graphene, we find that the velocity parameter increases significantly from $(1.23\pm 0.01) \times 10^6~\mathrm{m.s^{-1}}$ up to $(1.45\pm0.02) \times 10^6~\mathrm{m.s^{-1}}$ as the first to third optically-active inter LL transition couple to the G-mode phonon. This result is understood as a signature of enhanced many-body effects in unscreened graphene., Comment: 8 pages, 5 figures

Published
2020
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14. Reconfigurable 2D/0D p-n Graphene/HgTe Nanocrystal Heterostructure for Infrared Detection

Author

Louis Donald Notemgnou Mouafo, Ulrich Nguétchuissi Noumbé, Luis E. Parra López, Audrey Chu, Clément Livache, Jean-Francois Dayen, Abdelkarim Ouerghi, Charlie Gréboval, Bernard Doudin, Hicham Majjad, Julien Chaste, Stéphane Berciaud, Emmanuel Lhuillier, chaste, julien, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Physico-chimie et dynamique des surfaces (INSP-E6), Institut des Nanosciences de Paris (INSP), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), lhuillier, emmanuel, Sorbonne Universités à Paris pour l'Enseignement et la Recherche - - SUPER2011 - ANR-11-IDEX-0004 - IDEX - VALID, Hétérostructures bi-dimendionnelles hybrides pour l'optoélectronique - - H2DH2015 - ANR-15-CE24-0016 - AAPG2015 - VALID, APPEL À PROJETS GÉNÉRIQUE 2018 - Nanocristaux de perovskite inorganique pour la nanophotonique - - IPER-Nano22018 - ANR-18-CE30-0023 - AAPG2018 - VALID, Détecteur plasmonique à nanoCristaux colloïdaux: une nouvelle filière pour l'OPtoélectronique INfrarouge - - COPIN2019 - ANR-19-CE24-0022 - AAPG2019 - VALID, Nanocristaux Colloïdaux Dopés Infrarouges - - FRONTAL2019 - ANR-19-CE09-0017 - AAPG2019 - VALID, Tuning Giant Rashba Spin-Orbit Coupling in Polar Single Layer Transition Metal Dichalcogenides - - GRaSkop2019 - ANR-19-CE09-0026 - AAPG2019 - VALID, ERC blackQD - blackQD - 756225 - INCOMING, ANR-11-IDEX-0004,SUPER,Sorbonne Universités à Paris pour l'Enseignement et la Recherche(2011), ANR-15-CE24-0016,H2DH,Hétérostructures bi-dimendionnelles hybrides pour l'optoélectronique(2015), ANR-18-CE30-0023,IPER-Nano2,Nanocristaux de perovskite inorganique pour la nanophotonique(2018), ANR-19-CE24-0022,COPIN,Détecteur plasmonique à nanoCristaux colloïdaux: une nouvelle filière pour l'OPtoélectronique INfrarouge(2019), ANR-19-CE09-0017,FRONTAL,Nanocristaux Colloïdaux Dopés Infrarouges(2019), ANR-19-CE09-0026,GRaSkop,Tuning Giant Rashba Spin-Orbit Coupling in Polar Single Layer Transition Metal Dichalcogenides(2019), European Project: 756225,blackQD, Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)

Subjects
Electron mobility, Materials science, General Physics and Astronomy, 02 engineering and technology, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Capacitance, HgTe, law.invention, [PHYS] Physics [physics], law, General Materials Science, gate induced diode, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], narrow band gap nanocrystals, Photocurrent, [PHYS]Physics [physics], business.industry, Graphene, graphene, General Engineering, Heterojunction, infrared detection, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Photodiode, Semiconductor, Optoelectronics, 0210 nano-technology, business, [PHYS.COND] Physics [physics]/Condensed Matter [cond-mat], Dark current
Abstract

International audience; Nanocrystals are promising building blocks for the development of low-cost infrared optoelectronics. Gating a nanocrystal film in a phototransistor geometry is commonly proposed as a strategy to tune the signal to noise ratio by carefully controlling the carrier density within the semiconductor. However, the performance improvement has so far been quite marginal. With metallic electrodes, the gate dependence of the photocurrent follows the gate-induced change of the dark current. Graphene presents key advantages: (i) infrared transparency that allows back-side illumination, (ii) vertical electric field transparency and (iii) carrier selectivity under gate bias. Here, we investigate a configuration of 2D/0D infrared photodetectors taking advantage of a high capacitance ionic glass gate, large scale graphene electrodes, and a HgTe nanocrystal layer of high carrier mobility. The introduction of graphene electrodes combined with ionic glass enables to reconfigure selectively the HgTe nanocrystals and the graphene electrodes between electrons (n) and holes (p) doped states. We unveil that this functionality enables to design a 2D/0D p-n junction that expands throughout the device, with a built-in electric field that assists charge dissociation. We demonstrate that in this specific configuration, the signal to noise ratio for infrared photodetection can be enhanced by two orders of magnitude, and that photovoltaic operation can be achieved. The detectivity now reaches 109 Jones while the device only absorbs 8% of the incident light. Additionally, the time response of the device is fast (

Published
2020
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15. Room temperature chiral coupling of valley excitons with spin-momentum locked surface plasmons

Author

Yuri Gorodetski, James A. Hutchison, Stéphane Berciaud, Thomas W. Ebbesen, Shaojun Wang, Stefano Azzini, Etienne Lorchat, Cyriaque Genet, Thibault Chervy, Photonics and Semiconductor Nanophysics, and Surface Photonics

Subjects
Physics, Condensed matter physics, Exciton, Surface plasmon, 02 engineering and technology, 021001 nanoscience & nanotechnology, Polarization (waves), 01 natural sciences, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Condensed Matter::Materials Science, Transition metal, 0103 physical sciences, Monolayer, Polariton, Chimie/Autre, Electrical and Electronic Engineering, 010306 general physics, 0210 nano-technology, Excitation, Biotechnology, Coherence (physics)
Abstract

We demonstrate room temperature chiral coupling of valley excitons in a transition metal dichalcogenide monolayer with spin-momentum locked surface plasmons. At the onset of the strong coupling regime, we measure spin-selective excitation of directional flows of polaritons. Operating under such conditions, our platform yields surprisingly robust intervalley contrasts (ca. 40%) and coherence (ca. 5-8%) as opposed to their total absence for the uncoupled valley excitons at room temperature. These results open rich possibilities, easy to implement, in the context of chiral optical networks.

Published
2018
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16. Rigid-layer Raman-active modes inN-layer transition metal dichalcogenides: interlayer force constants and hyperspectral Raman imaging

Author

Guillaume Froehlicher, Etienne Lorchat, Olivia Zill, Michelangelo Romeo, and Stéphane Berciaud

Subjects
Materials science, 02 engineering and technology, 021001 nanoscience & nanotechnology, Trigonal prismatic molecular geometry, 01 natural sciences, Molecular physics, Shear (sheet metal), symbols.namesake, Octahedron, Transition metal, 0103 physical sciences, symbols, Wavenumber, General Materials Science, 010306 general physics, 0210 nano-technology, Raman spectroscopy, Layer (electronics), Spectroscopy, Order of magnitude
Abstract

We report a comparative study of rigid layer Raman-active modes in $N$-layer transition metal dichalcogenides. Trigonal prismatic (2Hc, such as MoSe$_2$, MoTe$_2$, WS$_2$, WSe$_2$) and distorted octahedral (1T', such as ReS$_2$ and ReSe$_2$) phases are considered. The Raman-active in-plane interlayer shear modes and out-of-plane interlayer breathing modes appear as well-defined features with wavenumbers in the range 0-40~cm$^{-1}$. These rigid layer modes are well-described by an elementary linear chain model from which the interlayer force constants are readily extracted. Remarkably, these force constants are all found to be of the same order of magnitude. Finally, we show that the prominent interlayer shear and breathing mode features allow high-precision hyperspectral Raman imaging of $N-$layer domains within a given transition metal dichalcogenide flake.

Published
2017
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17. Scanning Tunneling Microscope-Induced Excitonic Luminescence of a Two-Dimensional Semiconductor

Author

Stéphane Berciaud, Gérald Dujardin, Guillaume Schull, Luis E. Parra López, Delphine Pommier, Eric Le Moal, Andrew J. Mayne, Elizabeth Boer-Duchemin, Florentin Fabre, Rémi Bretel, Institut des Sciences Moléculaires d'Orsay (ISMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), ANR-15-CE24-0016,H2DH,Hétérostructures bi-dimendionnelles hybrides pour l'optoélectronique(2015), ANR-15-CE24-0020,INTELPLAN,Une nanosource de plasmons électrique et intégrée(2015), ANR-16-CE24-0003,M-Exc-ICO,Excitonique moléculaire pour l'optoélectronique cohérente intégrée(2016), ANR-10-IDEX-0002-02/11-LABX-0058,NIE,Nanostructures en Interaction avec leur Environnement(2010), European Project: 771850,APOGEE, Nanophysique et Surfaces, Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), ANR-10-IDEX-0002,UNISTRA,Par-delà les frontières, l'Université de Strasbourg(2010), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Photoluminescence, Band gap, Exciton, General Physics and Astronomy, 01 natural sciences, 7. Clean energy, law.invention, chemistry.chemical_compound, Condensed Matter::Materials Science, Tunnel junction, law, 0103 physical sciences, Spontaneous emission, 010306 general physics, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], business.industry, Condensed Matter::Other, Heterojunction, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, chemistry, Molybdenum diselenide, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [SPI.OPTI]Engineering Sciences [physics]/Optics / Photonic, Optoelectronics, Scanning tunneling microscope, business
Abstract

International audience; The long sought-after goal of locally and spectroscopically probing the excitons of two-dimensional (2D) semiconductors is attained using a scanning tunneling microscope (STM). Excitonic luminescence from monolayer molybdenum diselenide (MoSe 2) on a transparent conducting substrate is electrically excited in the tunnel junction of an STM under ambient conditions. By comparing the results with photoluminescence measurements, the emission mechanism is identified as the radiative recombination of bright A excitons. STM-induced luminescence is observed at bias voltages as low as those that correspond to the energy of the optical band gap of MoSe 2. The proposed excitation mechanism is resonance energy transfer from the tunneling current to the excitons in the semiconductor, i.e., through virtual photon coupling. Additional mechanisms (e.g., charge injection) may come into play at bias voltages that are higher than the electronic band gap. Photon emission quantum efficiencies of up to 10 −7 photons per electron are obtained, despite the lack of any participating plasmons. Our results demonstrate a new technique for investigating the excitonic and optoelectronic properties of 2D semiconductors and their heterostructures at the nanometer scale.

Published
2019
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18. Quasi-two-dimensional electron–hole droplets

Author

Stéphane Berciaud, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), and Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Condensed matter physics, Photoresistor, Electron-hole droplets, Liquid phase, 02 engineering and technology, Electron, 021001 nanoscience & nanotechnology, Chromatin remodelling, 01 natural sciences, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, law.invention, 010309 optics, Condensed Matter::Materials Science, law, 0103 physical sciences, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], 0210 nano-technology
Abstract

The observation of a room-temperature stable liquid phase of electrons and holes in a quasi-two-dimensional photocell paves the way towards optoelectronic devices that harness collective phenomena.

Published
2019
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19. Doping- and interference-free measurement of I2D/IG in suspended monolayer graphene blisters

Author

Stéphane Berciaud, Guillaume Froehlicher, and Dominik Metten

Subjects
Materials science, Graphene, Doping, Physics::Optics, Nanotechnology, Substrate (electronics), Condensed Matter Physics, Molecular physics, Electronic, Optical and Magnetic Materials, law.invention, symbols.namesake, law, Monolayer, symbols, Raman spectroscopy, Bilayer graphene, Graphene nanoribbons, Graphene oxide paper
Abstract

We report on strong interference effects on the ratio of the integrated intensities of the Raman 2D- and G-mode features (herein denoted ) in suspended graphene monolayers. Free from substrate-induced doping and residual charge inhomogeneity, suspended samples are an ideal platform to study the intrinsic properties of graphene. Here, we demonstrate that , measured on a pressurized suspended graphene blister, depends very sensitively on the distance between the bulged graphene membrane and the underlying substrate. The data obtained on three different samples are fit to theoretically predicted Raman enhancement factors and allow to extract an intrinsic, i.e., doping- and interference-free, value of for undoped, unscreened graphene at a laser photon energy of .

Published
2015
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20. Room temperature dry processing of patterned CVD graphene devices

Author

Bernard Doudin, Cheol-Soo Yang, Serin Park, Jean-Francois Dayen, Stéphane Berciaud, Jeong-O Lee, M. Venkata Kamalakar, Dominik Metten, and Ather Mahmood

Subjects
Organic electronics, Materials science, Graphene, Nanotechnology, General Chemistry, Quantum Hall effect, Monolayer graphene, law.invention, Planar, law, General Materials Science, Cvd graphene, Lithography, Single layer
Abstract

We present a strategy for avoiding polymeric residues, excessive heating and solvent exposure when transforming large area transferred CVD graphene single layer films into series of planar devices. Such dry process is a key prerequisite for chemical functionalization applications or for organic electronics compatibility, and opens the possibility to integrate graphene electrodes with thermally or chemically sensitive materials, as well as substrates incompatible with lithography processing. Patterning and metal evaporation are performed through a multi-step mechanical stencils methodology, and low temperatures magneto transport measurements are used to validate devices with preserved electrical fingerprints of graphene. This is particularly critical for the argon beam milling process step. Remarkably, the Quantum Hall signature of our devices remains robust, even though defective sample edges result from the beam exposure. Shubnikov-de Hass (SdH) oscillations and weak (anti-) localization signatures of monolayer graphene confirm the excellent intrinsic properties of such processed samples, rarely observed on CVD-processed devices.

Published
2015
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21. Interface dipole and band bending in the hybrid p−n heterojunction MoS2/GaN(0001)

Author

Carl H. Naylor, Hugo Henck, Julien E. Rault, Mathieu G. Silly, Fabrice Oehler, Julien Brault, A. T. Charlie Johnson, Patrick Le Fèvre, François Bertran, Stéphane Berciaud, Olivia Zill, Stéphane Collin, Abdelkarim Ouerghi, Noelle Gogneau, Fausto Sirotti, Zeineb Ben Aziza, Debora Pierucci, and Emmanuel Lhuillier

Subjects
Materials science, Photoemission spectroscopy, business.industry, Fermi level, Angle-resolved photoemission spectroscopy, Heterojunction, 02 engineering and technology, Electronic structure, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Condensed Matter::Materials Science, symbols.namesake, Dipole, Band bending, Condensed Matter::Superconductivity, Monolayer, symbols, Optoelectronics, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology, business
Abstract

Hybrid heterostructures based on bulk GaN and two-dimensional (2D) materials offer novel paths toward nanoelectronic devices with engineered features. Here, we study the electronic properties of a mixed-dimensional heterostructure composed of intrinsic n-doped MoS2 flakes transferred on p-doped GaN(0001) layers. Based on angle-resolved photoemission spectroscopy (ARPES) and high resolution x-ray photoemission spectroscopy (HR-XPS), we investigate the electronic structure modification induced by the interlayer interactions in MoS2/GaN heterostructure. In particular, a shift of the valence band with respect to the Fermi level for MoS2/GaN heterostructure is observed, which is the signature of a charge transfer from the 2D monolayer MoS2 to GaN. The ARPES and HR-XPS revealed an interface dipole associated with local charge transfer from the GaN layer to the MoS2 monolayer. Valence and conduction band offsets between MoS2 and GaN are determined to be 0.77 and −0.51eV, respectively. Based on the measured work functions and band bendings, we establish the formation of an interface dipole between GaN and MoS2 of 0.2 eV.

Published
2017
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22. Graphene hybrid optomechanical plateform for probing interplay between internal and macroscopic degree of freedom

Author

Stéphane Berciaud, Xin Zhang Pierre Vertat, Kevin Makles, Dominik Metten, Laboratoire Kastler Brossel (LKB (Jussieu)), Université Pierre et Marie Curie - Paris 6 (UPMC)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Physics, Graphene, Solid-state, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, law.invention, [SPI]Engineering Sciences [physics], Resonator, Macroscopic scale, law, Robustness (computer science), Physical phenomena, [CHIM]Chemical Sciences, 0210 nano-technology, Quantum, ComputingMilieux_MISCELLANEOUS
Abstract

Solid state nanomechanical systems have received increased interest in applied and fundamental science in the past fifteen years. The combination of a very low mass and physical robustness has enabled measuring and demonstrating a variety of physical phenomena to an unprecedented level of accuracy, such as quantum behaviour at the macroscopic scale [1] and single interaction [2]. In particular, low dimension carbon based nanomechanical resonators have attracted a keen interest, with spectacular sensing performances [3].

Published
2017
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24. Tuning contact transport mechanisms in bilayer MoSe 2 transistors up to Fowler–Nordheim regime

Author

Bernard Doudin, M. Venkata Kamalakar, Florian Godel, Guillaume Froehlicher, Louis Donald Notemgnou Mouafo, Stéphane Berciaud, Jean-Francois Dayen, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), and Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Schottky barrier, Nanotechnology, Thermionic emission, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, chemistry.chemical_compound, General Materials Science, Quantum tunnelling, business.industry, Mechanical Engineering, General Chemistry, Semiconductor device, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, [SPI.ELEC]Engineering Sciences [physics]/Electromagnetism, Band bending, Semiconductor, chemistry, Mechanics of Materials, Molybdenum diselenide, Optoelectronics, Field-effect transistor, 0210 nano-technology, business
Abstract

Atomically thin molybdenum diselenide (MoSe 2 ) is an emerging two-dimensional (2D) semiconductor with significant potential for electronic, optoelectronic, spintronic applications and a common platform for their possible integration. Tuning interface charge transport between such new 2D materials and metallic electrodes is a key issue in 2D device physics and engineering. Here, we report tunable interface charge transport in bilayer MoSe 2 field effect transistors with Ti/Au contacts showing high on/off ratio up to 10 7 at room temperature. Our experiments reveal a detailed map of transport mechanisms obtained by controlling the interface band bending profile via temperature, gate and source-drain bias voltages. This comprehensive investigation leads to demarcating regimes and tuning in transport mechanisms while controlling the interface barrier profile. The careful analysis allows us to identify thermally activated regime at low carrier density, and Schottky barrier driven mechanisms at higher carrier density demonstrating the transition from low-field direct tunneling/ thermionic emission to high-field Fowler–Nordheim tunneling. Furthermore, we show that the transition voltage V trans to Fowler–Nordheim correlates directly to the difference between the chemical potential of the metal electrode and the conduction band minimum in the 2D semiconductor, which opens up opportunities for new theoretical and experimental investigations. Our approach being generic can be extended to other 2D materials, and the possibility of tuning contact transport regimes is promising for designing MoSe 2 device applications.

Published
2017
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25. Vibronic Spectroscopy with Submolecular Resolution from STM-Induced Electroluminescence

Author

Fabrice Scheurer, Hervé Bulou, Alex Boeglin, Stéphane Berciaud, Michelangelo Romeo, Etienne Lorchat, Benjamin Doppagne, Michael C. Chong, Guillaume Schull, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), univOAK, Archive ouverte, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.MATE] Chemical Sciences/Material chemistry, Materials science, Resolution (electron density), General Physics and Astronomy, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, Electroluminescence, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, 01 natural sciences, Fluorescence, 3. Good health, law.invention, law, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Vibronic spectroscopy, Molecule, Scanning tunneling microscope, Atomic physics, Physics::Chemical Physics, 010306 general physics, 0210 nano-technology
Abstract

A scanning tunneling microscope is used to generate the electroluminescence of phthalocyanine molecules deposited on NaCl/Ag(111). Photon spectra reveal an intense emission line at approximate to 1.9 eV that corresponds to the fluorescence of the molecules, and a series of weaker redshifted lines. Based on a comparison with Raman spectra acquired on macroscopic molecular crystals, these spectroscopic features can be associated with the vibrational modes of the molecules and provide a detailed chemical fingerprint of the probed species. Maps of the vibronic features reveal submolecularly resolved structures whose patterns are related to the symmetry of the probed vibrational modes.

Published
2017
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26. Probing built-in strain in freestanding graphene monolayers by Raman spectroscopy

Author

François Federspiel, Stéphane Berciaud, Dominik Metten, and Michelangelo Romeo

Subjects
Materials science, Strain (chemistry), Graphene, Spatially resolved, Doping, Nanotechnology, Condensed Matter Physics, Molecular physics, Electronic, Optical and Magnetic Materials, law.invention, symbols.namesake, law, Ultimate tensile strength, Monolayer, symbols, Raman spectroscopy, Raman scattering
Abstract

We report a detailed spatially resolved Raman study on a set of eight pristine freestanding graphene monolayers. While we find, as previously reported, that freestanding graphene is quasi-undoped, our study also reveals that non-negligible built-in strain occurs in these samples. The level of built-in strain varies significantly from one sample to another and can be estimated with accuracy from the correlation of the frequencies of the G and 2D Raman modes. Sample-dependent compressive and tensile strains as high as 0.1% are reported.

Published
2013
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27. Intrinsic Line Shape of the Raman 2D-Mode in Freestanding Graphene Monolayers

Author

Stéphane Berciaud, Han Htoon, Stephen K. Doorn, Xianglong Li, Louis E. Brus, and Tony F. Heinz

Subjects
Physics, Photon, Condensed Matter - Mesoscale and Nanoscale Physics, Graphene, Phonon, Mechanical Engineering, Doping, FOS: Physical sciences, Bioengineering, General Chemistry, Photon energy, Condensed Matter Physics, Molecular physics, law.invention, Brillouin zone, symbols.namesake, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Monolayer, symbols, General Materials Science, Raman spectroscopy
Abstract

We report a comprehensive study of the two-phonon inter-valley (2D) Raman mode in graphene monolayers, motivated by recent reports of asymmetric 2D-mode lineshapes in freestanding graphene. For photon energies in the range $1.53 \rm eV - 2.71 \rm eV$, the 2D-mode Raman response of freestanding samples appears as bimodal, in stark contrast with the Lorentzian approximation that is commonly used for supported monolayers. The transition between the freestanding and supported cases is mimicked by electrostatically doping freestanding graphene at carrier densities above $2\times 10^{11} \rm cm^{-2}$. This result quantitatively demonstrates that low levels of charging can obscure the intrinsically bimodal 2D-mode lineshape of monolayer graphene, which can be utilized as a signature of a quasi-neutral sample. In pristine freestanding graphene, we observe a broadening of the 2D-mode feature with decreasing photon energy that cannot be rationalized using a simple one-dimensional model based on resonant \textit{inner} and \textit{outer} processes. This indicates that phonon wavevectors away from the high-symmetry lines of the Brillouin zone must contribute to the 2D-mode, so that a full two-dimensional calculation is required to properly describe multiphonon-resonant Raman processes.

Published
2013
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28. Conductance Oscillations in a Graphene/Nanocluster Hybrid Material: Toward Large-Area Single-Electron Devices

Author

Yves Henry, D. Halley, Louis Donald Notemgnou Mouafo, Stéphane Berciaud, Jean-Francois Dayen, Bernard Doudin, Guillaume Froehlicher, Florian Godel, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and univOAK, Archive ouverte

Subjects
Materials science, Oxide, Nanoparticle, chemistry.chemical_element, FOS: Physical sciences, Nanotechnology, 02 engineering and technology, 01 natural sciences, 7. Clean energy, Nanoclusters, law.invention, chemistry.chemical_compound, Aluminium, law, 0103 physical sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Materials Science, 010306 general physics, Condensed Matter - Materials Science, [CHIM.MATE] Chemical Sciences/Material chemistry, Condensed Matter - Mesoscale and Nanoscale Physics, Graphene, Mechanical Engineering, Conductance, Materials Science (cond-mat.mtrl-sci), [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, chemistry, Mechanics of Materials, 0210 nano-technology, Hybrid material, Layer (electronics)
Abstract

Large assemblies of self-organized aluminum nanoclusters embedded in an oxide layer are formed on graphene templates and used to build tunnel-junction devices. Unexpectedly, single-electron-transport behavior with well-defined Coulomb oscillations is observed for a record junction area of up to 100 mu m(2) containing millions of metal islands. Such graphene-metal nanocluster hybrid materials offer new prospects for single-electron electronics.

Published
2016
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29. Direct versus indirect band gap emission and exciton-exciton annihilation in atomically thin molybdenum ditelluride(MoTe2)

Author

Etienne Lorchat, Guillaume Froehlicher, and Stéphane Berciaud

Subjects
Physics, Condensed Matter - Materials Science, Photoluminescence, Annihilation, Condensed Matter - Mesoscale and Nanoscale Physics, Band gap, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Quantum yield, 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Direct and indirect band gaps, Emission spectrum, Atomic physics, 010306 general physics, 0210 nano-technology, Intensity (heat transfer), Energy (signal processing)
Abstract

We probe the room temperature photoluminescence of $N$-layer molybdenum ditelluride $({\mathrm{MoTe}}_{2})$ in the continuous wave (cw) regime. The photoluminescence quantum yield of monolayer ${\mathrm{MoTe}}_{2}$ is three times larger than in bilayer ${\mathrm{MoTe}}_{2}$ and 40 times greater than in the bulk limit. Mono- and bilayer ${\mathrm{MoTe}}_{2}$ display almost symmetric emission lines at 1.10 and 1.07 eV, respectively, which predominantly arise from direct radiative recombination of the A exciton. In contrast, $N\ensuremath{\ge}3\ensuremath{-}\mathrm{layer}\phantom{\rule{4pt}{0ex}}{\mathrm{MoTe}}_{2}$ exhibits a much reduced photoluminescence quantum yield and a broader, redshifted, and seemingly bimodal photoluminescence spectrum. The low- and high-energy contributions are attributed to emission from the indirect and direct optical band gaps, respectively. Bulk ${\mathrm{MoTe}}_{2}$ displays a broad emission line with a dominant contribution at 0.94 eV that is assigned to emission from the indirect optical band gap. As compared to related systems (such as ${\mathrm{MoS}}_{2},\phantom{\rule{0.16em}{0ex}}{\mathrm{MoSe}}_{2},\phantom{\rule{0.16em}{0ex}}{\mathrm{WS}}_{2}$, and ${\mathrm{WSe}}_{2}$), the smaller energy difference between the monolayer direct optical band gap and the bulk indirect optical band gap leads to a smoother increase of the photoluminescence quantum yield as $N$ decreases. In addition, we study the evolution of the photoluminescence intensity in monolayer ${\mathrm{MoTe}}_{2}$ as a function of the exciton formation rate ${W}_{\mathrm{abs}}$ up to $3.6\ifmmode\times\else\texttimes\fi{}{10}^{22}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}\phantom{\rule{0.16em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$. The line shape of the photoluminescence spectrum remains largely independent of ${W}_{\mathrm{abs}}$, whereas the photoluminescence intensity grows sublinearly above ${W}_{\mathrm{abs}}\ensuremath{\sim}{10}^{21}\phantom{\rule{4pt}{0ex}}{\mathrm{cm}}^{\ensuremath{-}2}\phantom{\rule{0.16em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$. This behavior is assigned to exciton-exciton annihilation and is well captured by an elementary rate equation model.

Published
2016
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30. All-optical structure assignment of individual single-walled carbon nanotubes from Rayleigh and Raman scattering measurements

Author

Stéphane Berciaud, Yuhei Miyauchi, Christophe Voisin, Tony F. Heinz, Philip Kim, Vikram Deshpande, James Hone, and Robert Caldwell

Subjects
Materials science, business.industry, Exciton, Structure (category theory), Carbon nanotube, Photon energy, Condensed Matter Physics, Molecular physics, Spectral line, Electronic, Optical and Magnetic Materials, law.invention, symbols.namesake, Optics, law, symbols, Rayleigh scattering, business, Raman spectroscopy, Raman scattering
Abstract

We present an all-optical method for structure assignment of individual single-walled carbon nanotubes (SWNTs) based on combined measurements of the elastically (Rayleigh) and inelastically (Raman) scattered light by individual freestanding specimens. The optical resonances of a single SWNT are identified from the Rayleigh spectra. These measurements are complemented with an independent estimation of the SWNT diameter and chiral angle from its radial breathing and G Raman modes, respectively. An assignment of the (n,m) chiral indices can thus be provided. In the most simple cases, a reliable structure assignment can be inferred from the Rayleigh spectra alone. However, we also show that SWNTs with different structures may display similar Rayleigh spectra within a given photon energy window. In these situations, Raman measurements provide unambiguous criteria for a proper structure assignment. This approach is particularly helpful in order to identify the high-symmetry armchair and zig-zag structures.

Published
2012
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31. Atmospheric Oxygen Binding and Hole Doping in Deformed Graphene on a SiO2 Substrate

Author

Sunmin Ryu, Stéphane Berciaud, George W. Flynn, Philip Kim, Louis E. Brus, Young-Jun Yu, Li Liu, and Haitao Liu

Subjects
inorganic chemicals, Materials science, Silicon dioxide, FOS: Physical sciences, chemistry.chemical_element, Bioengineering, Substrate (electronics), Condensed Matter - Soft Condensed Matter, Oxygen, law.invention, Condensed Matter::Materials Science, chemistry.chemical_compound, symbols.namesake, law, General Materials Science, Physics::Chemical Physics, Spectroscopy, Condensed Matter - Materials Science, Graphene, Mechanical Engineering, Doping, technology, industry, and agriculture, Materials Science (cond-mat.mtrl-sci), General Chemistry, Condensed Matter Physics, chemistry, Chemical physics, symbols, Soft Condensed Matter (cond-mat.soft), Scanning tunneling microscope, Raman spectroscopy
Abstract

Using micro-Raman spectroscopy and scanning tunneling microscopy, we study the relationship between structural distortion and electrical hole doping of graphene on a silicon dioxide substrate. The observed upshift of the Raman G band represents charge doping and not compressive strain. Two independent factors control the doping: (1) the degree of graphene coupling to the substrate, and (2) exposure to oxygen and moisture. Thermal annealing induces a pronounced structural distortion due to close coupling to SiO2 and activates the ability of diatomic oxygen to accept charge from graphene. Gas flow experiments show that dry oxygen reversibly dopes graphene; doping becomes stronger and more irreversible in the presence of moisture and over long periods of time. We propose that oxygen molecular anions are stabilized by water solvation and electrostatic binding to the silicon dioxide surface., Comment: 17 pages, 5 figures

Published
2010
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32. Energy Transfer from Individual Semiconductor Nanocrystals to Graphene

Author

Zheyuan Chen, Stéphane Berciaud, Tony F. Heinz, Colin Nuckolls, and Louis E. Brus

Subjects
Chemical Physics (physics.chem-ph), Condensed Matter - Materials Science, Quenching (fluorescence), Materials science, Graphene, business.industry, Energy transfer, General Engineering, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, General Physics and Astronomy, Discrete dipole approximation, Fluorescence, law.invention, Metal, Dipole, Nanocrystal, law, Physics - Chemical Physics, visual_art, visual_art.visual_art_medium, Optoelectronics, General Materials Science, business
Abstract

Energy transfer from photoexcited zero-dimensional systems to metallic systems plays a prominent role in modern day materials science. A situation of particular interest concerns the interaction between a photoexcited dipole and an atomically thin metal. The recent discovery of graphene layers permits investigation of this phenomenon. Here we report a study of fluorescence from individual CdSe/ZnS nanocrystals in contact with single- and few-layer graphene sheets. The rate of energy transfer is determined from the strong quenching of the nanocrystal fluorescence. For single-layer graphene, we find a rate of approximately 4 ns(-1), in agreement with a model based on the dipole approximation and a tight-binding description of graphene. This rate increases significantly with the number of graphene layers, before approaching the bulk limit. Our study quantifies energy transfer to and fluorescence quenching by graphene, critical properties for novel applications in photovoltaic devices and as a molecular ruler.

Published
2010
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33. Photothermal Methods for Single Nonluminescent Nano-Objects

Author

David Lasne, Stéphane Berciaud, Brahim Lounis, and Laurent Cognet

Subjects
Optics, Hardware_GENERAL, Quantum dot, Chemistry, business.industry, Nano, Nanotechnology, Heterodyne detection, Photothermal therapy, business, Analytical Chemistry
Abstract

New optical methods allow the detection of tiny individual nano-objects, opening a wide range of applications.

Published
2008
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34. Unified description of the optical phonon modes in $N$-layer MoTe$_2$

Author

Stéphane Berciaud, Guillaume Froehlicher, François Fernique, Alejandro Molina-Sanchez, Ludger Wirtz, Chaitanya Joshi, Etienne Lorchat, Fonds National de la Recherche - FnR [sponsor], University of Luxembourg - UL [sponsor], and University of Luxembourg: High Performance Computing - ULHPC [research center]

Subjects
Phonon, Bulk, Transition Metal Dichalcogenides, General Materials Science, two-dimensional materials, Raman-Scattering, Condensed Matter - Materials Science, Condensed matter physics, Chemistry, Force Constants, transition metal dichalcogenides, Interlayer Breathing And Shear Modes, Mote2, Condensed Matter Physics, Layered Crystals, Monolayer Mos2, Shear (sheet metal), Physique [G04] [Physique, chimie, mathématiques & sciences de la terre], Raman spectroscopy, symbols, Davydov Splitting, Band-Gap, Raman Spectroscopy, Alpha-Mote2, surface effects, Physics [G04] [Physical, chemical, mathematical & earth Sciences], MoTe2, FOS: Physical sciences, Surface Effects, Bioengineering, Wse2, layered crystals, Transistors, interlayer breathing and shear modes, Crystals, symbols.namesake, Chalcogen, Transition metal, Monolayer, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Spectroscopy, Photoluminescence, force constants, Two-Dimensional Materials, Transition-Metal Dichalcogenides, Series (mathematics), Condensed Matter - Mesoscale and Nanoscale Physics, Mechanical Engineering, Materials Science (cond-mat.mtrl-sci), Davydov splitting, General Chemistry
Abstract

$N$-layer transition metal dichalcogenides provide a unique platform to investigate the evolution of the physical properties between the bulk (three dimensional) and monolayer (quasi two-dimensional) limits. Here, using high-resolution micro-Raman spectroscopy, we report a unified experimental description of the $\Gamma$-point optical phonons in $N$-layer $2H$-molybdenum ditelluride (MoTe$_2$). We observe a series of $N$-dependent low-frequency interlayer shear and breathing modes (below $40~\rm cm^{-1}$, denoted LSM and LBM) and well-defined Davydov splittings of the mid-frequency modes (in the range $100-200~\rm cm^{-1}$, denoted iX and oX), which solely involve displacements of the chalcogen atoms. In contrast, the high-frequency modes (in the range $200-300~\rm cm^{-1}$, denoted iMX and oMX), arising from displacements of both the metal and chalcogen atoms, exhibit considerably reduced splittings. The manifold of phonon modes associated with the in-plane and out-of-plane displacements are quantitatively described by a force constant model, including interactions up to the second nearest neighbor and surface effects as fitting parameters. The splittings for the iX and oX modes observed in $N$-layer crystals are directly correlated to the corresponding bulk Davydov splittings between the $E_{2u}/E_{1g}$ and $B_{1u}/A_{1g}$ modes, respectively, and provide a measurement of the frequencies of the bulk silent $E_{2u}$ and $B_{1u}$ optical phonon modes. Our analysis could readily be generalized to other layered crystals., Comment: Main Text (5 Figures, 2 Tables) + Supporting Information (12 Figures)

Published
2015

35. Landau Level Spectroscopy of Electron-Electron Interactions in Graphene

Author

P. Leszczynski, T. Taniguchi, Philip Kim, Milan Orlita, K. Nogajewski, Clément Faugeras, Denis M. Basko, Rashid Jalil, Stéphane Berciaud, Marek Potemski, Y. Henni, Kenji Watanabe, Carlos Forsythe, Andre K. Geim, Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), National Institute for Fusion Science (NIFS), ETRI, Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-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), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace, Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Université de Strasbourg (UNISTRA)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Université de Strasbourg (UNISTRA), National Institute for Materials Science (NIMS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Strongly Correlated Electrons (cond-mat.str-el), Condensed matter physics, Condensed Matter - Mesoscale and Nanoscale Physics, Scattering, Graphene, FOS: Physical sciences, General Physics and Astronomy, Electron, Landau quantization, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, law.invention, Magnetic field, Condensed Matter - Strongly Correlated Electrons, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], law, Dispersion relation, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Coulomb, Quasiparticle, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [PHYS.COND.CM-DS-NN]Physics [physics]/Condensed Matter [cond-mat]/Disordered Systems and Neural Networks [cond-mat.dis-nn], ComputingMilieux_MISCELLANEOUS
Abstract

We present magneto-Raman scattering studies of electronic inter Landau level excitations in quasi-neutral graphene samples with different strengths of Coulomb interaction. The band velocity associated with these excitations is found to depend on the dielectric environment, on the index of Landau level involved, and to vary as a function of the magnetic field. This contradicts the single-particle picture of non-interacting massless Dirac electrons, but is accounted for by theory when the effect of electron-electron interaction is taken into account. Raman active, zero-momentum inter Landau level excitations in graphene are sensitive to electron-electron interactions due to the non-applicability of the Kohn theorem in this system, with a clearly non-parabolic dispersion relation., 5+2 pages, 2 figures

Published
2015

36. Raman Spectroscopy of Electrochemically-Gated Graphene Transistors: Geometrical Capacitance, Electron-Phonon, Electron-Electron, and Electron-Defect Scattering

Author

Guillaume Froehlicher and Stéphane Berciaud

Subjects
Materials science, Condensed Matter - Mesoscale and Nanoscale Physics, Scattering, Graphene, business.industry, Fermi level, FOS: Physical sciences, Electron, Condensed Matter Physics, Capacitance, Electronic, Optical and Magnetic Materials, law.invention, symbols.namesake, Computer Science::Emerging Technologies, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), symbols, Optoelectronics, Physics::Chemical Physics, Raman spectroscopy, business, Raman scattering, Fermi Gamma-ray Space Telescope
Abstract

We report a comprehensive micro-Raman scattering study of electrochemically-gated graphene field-effect transistors. The geometrical capacitance of the electrochemical top-gates is accurately determined from dual-gated Raman measurements, allowing a quantitative analysis of the frequency, linewidth and integrated intensity of the main Raman features of graphene. The anomalous behavior observed for the G-mode phonon is in very good agreement with theoretical predictions and provides a measurement of the electron-phonon coupling constant for zone-center ($\Gamma$ point) optical phonons. In addition, the decrease of the integrated intensity of the 2D-mode feature with increasing doping, makes it possible to determine the electron-phonon coupling constant for near zone-edge (K and K' points) optical phonons. We find that the electron-phonon coupling strength at $\Gamma$ is five times weaker than at K (K'), in very good agreement with a direct measurement of the ratio of the integrated intensities of the resonant intra- (2D') and inter-valley (2D) Raman features. We also show that electrochemical reactions, occurring at large gate biases, can be harnessed to efficiently create defects in graphene, with concentrations up to approximately $1.4\times 10^{12}~\rm cm^{-2}$. At such defect concentrations, we estimate that the electron-defect scattering rate remains much smaller than the electron-phonon scattering rate. The evolution of the G- and 2D-mode features upon doping remain unaffected by the presence of defects and the doping dependence of the D mode closely follows that of its two-phonon (2D mode) overtone. Finally, the linewidth and frequency of the G-mode phonon as well as the frequencies of the G- and 2D-mode phonons in doped graphene follow sample-independent correlations that can be utilized for accurate estimations of the charge carrier density., Comment: 18 pages, 14 figures, 1 table

Published
2015
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37. Splitting of interlayer shear modes and photon energy dependent anisotropic Raman response in $N$-layer ReSe$_2$ and ReS$_2$

Author

Etienne Lorchat, Stéphane Berciaud, and Guillaume Froehlicher

Subjects
Materials science, Phonon, General Physics and Astronomy, FOS: Physical sciences, Nanotechnology, 02 engineering and technology, Photon energy, 010402 general chemistry, 01 natural sciences, Molecular physics, Condensed Matter::Materials Science, symbols.namesake, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Materials Science, Spectroscopy, Anisotropy, Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, General Engineering, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, Trigonal prismatic molecular geometry, 0104 chemical sciences, symbols, van der Waals force, 0210 nano-technology, Raman spectroscopy, Order of magnitude
Abstract

We investigate the interlayer phonon modes in $N$-layer rhenium diselenide (ReSe$_2$) and rhenium disulfide (ReS$_2$) by means of ultralow-frequency micro-Raman spectroscopy. These transition metal dichalcogenides exhibit a stable distorted octahedral (1T') phase with significant in-plane anisotropy, leading to sizable splitting of the (in-plane) layer shear modes. The fan-diagrams associated with the measured frequencies of the interlayer shear modes and the (out-of-plane) interlayer breathing modes are perfectly described by a finite linear chain model and allow the determination of the interlayer force constants. Nearly identical values are found for ReSe$_2$ and ReS$_2$. The latter are appreciably smaller than but on the same order of magnitude as the interlayer force constants reported in graphite and in trigonal prismatic (2Hc) transition metal dichalcogenides (such as MoS$_2$, MoSe$_2$, MoTe$_2$, WS$_2$, WSe$_2$), demonstrating the importance of van der Waals interactions in $N$-layer ReSe$_2$ and ReS$_2$. In-plane anisotropy results in a complex angular dependence of the intensity of all Raman modes, which can be empirically utilized to determine the crystal orientation. However, we also demonstrate that the angular dependence of the Raman response drastically depends on the incoming photon energy, shedding light on the importance of resonant exciton-phonon coupling in ReSe$_2$ and ReS$_2$.

Published
2015
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38. Distance Dependence of the Energy Transfer Rate From a Single Semiconductor Nanostructure to Graphene

Author

François Federspiel, Ather Mahmood, Michel Nasilowski, Serin Park, D. Halley, Pierre Gilliot, Bernard Doudin, Guillaume Froehlicher, Benoit Dubertret, Stéphane Berciaud, Silvia Pedetti, and Jeong-O Lee

Subjects
Resonant inductive coupling, Materials science, Exciton, Aucun, Physics::Optics, FOS: Physical sciences, Bioengineering, 7. Clean energy, Molecular physics, law.invention, Condensed Matter::Materials Science, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), General Materials Science, Quantum well, Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Graphene, Condensed Matter::Other, Mechanical Engineering, Materials Science (cond-mat.mtrl-sci), Heterojunction, General Chemistry, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Förster resonance energy transfer, Nanocrystal, Quantum dot
Abstract

The near-field Coulomb interaction between a nano-emitter and a graphene monolayer results in strong F\"orster-type resonant energy transfer and subsequent fluorescence quenching. Here, we investigate the distance dependence of the energy transfer rate from individual, i) zero-dimensional CdSe/CdS nanocrystals and ii) two-dimensional CdSe/CdS/ZnS nanoplatelets to a graphene monolayer. For increasing distances $d$, the energy transfer rate from individual nanocrystals to graphene decays as $1/d^4$. In contrast, the distance dependence of the energy transfer rate from a two-dimensional nanoplatelet to graphene deviates from a simple power law, but is well described by a theoretical model, which considers a thermal distribution of free excitons in a two-dimensional quantum well. Our results show that accurate distance measurements can be performed at the single particle level using graphene-based molecular rulers and that energy transfer allows probing dimensionality effects at the nanoscale., Comment: Main text (+ 5 figures) and Supporting Information (+ 7 figures)

Published
2015
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39. All-Optical Blister Test of Suspended Graphene Using Micro-Raman Spectroscopy

Author

Michelangelo Romeo, François Federspiel, Dominik Metten, and Stéphane Berciaud

Subjects
Nanoelectromechanical systems, Materials science, Condensed Matter - Mesoscale and Nanoscale Physics, Strain (chemistry), Graphene, FOS: Physical sciences, General Physics and Astronomy, Blisters, Bead test, law.invention, Micro raman spectroscopy, Stress (mechanics), law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), medicine, medicine.symptom, Composite material, Spectroscopy
Abstract

We report a comprehensive micro-Raman study of a pressurized suspended graphene membrane that hermetically seals a circular pit, etched in a Si/SiO$_2$ substrate. Placing the sample under a uniform pressure load results in bulging of the graphene membrane and subsequent softening of the main Raman features, due to tensile strain. In such a microcavity, the intensity of the Raman features depends very sensitively on the distance between the graphene membrane and the Si substrate, which acts as the bottom mirror of the cavity. Thus, a spatially resolved analysis of the intensity of the G- and 2D-mode features as a function of the pressure load permits a direct reconstruction of the blister profile. An average strain is then deduced at each pressure load, and Gr\"{u}neisen parameters of $1.8\pm0.2$ and $2.4\pm0.2$ are determined for the Raman G and 2D modes, respectively. In addition, the measured blister height is proportional to the cubic root of the pressure load, as predicted theoretically. The validation of this scaling provides a direct and accurate determination the Young's modulus of graphene with a purely optical, hence contactless and minimally invasive, approach. We find a Young's modulus of $(1.05\pm 0.10) \rm TPa$ for monolayer graphene, in a perfect match with previous nanoindentation measurements. This all-optical methodology opens avenues for pressure sensing using graphene and could readily be adapted to other emerging two-dimensional materials and nanoresonators., Comment: Manuscript File (11 pages, 7 figures) and Supplemental Material (6 pages, 9 figures)

Published
2014
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40. Size-induced enhanced magnetoelectric effect and multiferroicity in chromium oxide nanoclusters

Author

D. Halley, Yves Henry, Hicham Majjad, Stéphane Berciaud, Bernard Doudin, Philippe Ohresser, N. Najjari, Fabrice Scheurer, Loïc Joly, and Corinne Ulhaq-Bouillet

Subjects
Multidisciplinary, Materials science, Aucun, Magnetoelectric effect, Chromium oxide, General Physics and Astronomy, Multiferroics, Nanotechnology, General Chemistry, General Biochemistry, Genetics and Molecular Biology, Nanoclusters
Abstract

The control of the magnetization of a material with an electric field would make the design and the integration of novel electronic devices possible. This explains the renewed interest in multiferroic materials. Progress in this field is currently hampered by the scarcity of the materials available and the smallness of the magnetoelectric effects. Here we present a proof-of-principle experiment showing that engineering large strains through nanoscale size reduction is an efficient route for increasing magnetoelectric coefficients by orders of magnitude. The archetype magnetoelectric material, Cr2O3, in the form of epitaxial clusters, exhibits an unprecedented 600% change in magnetization magnitude under 1V. Furthermore, a multiferroic phase, with both magnetic and electric spontaneous polarizations, is found in the clusters, while absent in the bulk. We gratefully acknowledge A. Carvalho for SEM observations, J. Arabski for technical assistance during MBE growth, STnano staff for technical support during microfabrication, B. Muller for technical support while setting up DEIMOS beamline, DEIMOS beamline staff for help during synchrotron experiments, and M. Bailleul and V. Da Costa for magnetic and structural characterization measurements. N.N. thanks Région Alsace for financial support.

Published
2014
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41. Probing electronic excitations in mono- to pentalayer graphene by micro-magneto-Raman spectroscopy

Author

Stéphane Berciaud, Marek Potemski, Clément Faugeras, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées

Subjects
Physics, Range (particle radiation), Condensed matter physics, Condensed Matter - Mesoscale and Nanoscale Physics, Graphene, Mechanical Engineering, Bilayer, FOS: Physical sciences, Bioengineering, General Chemistry, Landau quantization, Quantum Hall effect, Condensed Matter Physics, law.invention, symbols.namesake, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), symbols, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science, [PHYS.COND.CM-DS-NN]Physics [physics]/Condensed Matter [cond-mat]/Disordered Systems and Neural Networks [cond-mat.dis-nn], Raman spectroscopy, Magneto, Image resolution, ComputingMilieux_MISCELLANEOUS
Abstract

We probe electronic excitations between Landau levels in freestanding $N-$layer graphene over a broad energy range, with unprecedented spectral and spatial resolution, using micro-magneto Raman scattering spectroscopy. A characteristic evolution of electronic bands in up to five Bernal-stacked graphene layers is evidenced and shown to remarkably follow a simple theoretical approach, based on an effective bilayer model. $(N>3)$-layer graphene appear as appealing candidates in the quest for novel phenomena, particularly in the quantum Hall effect regime. Our work paves the way towards minimally-invasive investigations of magneto-excitons in other emerging low-dimensional systems, with a spatial resolution down to 1$~��$m., to appear in Nano Letters

Published
2014
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42. Biexciton, single carrier, and trion generation dynamics in single-walled carbon nanotubes

Author

Stéphane Berciaud, Marc Ziegler, Pierre Gilliot, Saunab Ghosh, Jean Besbas, Brahim Lounis, Bertrand Yuma, Silvia M. Santos, R. B. Weisman, Laurent Cognet, Mathieu Gallart, Bernd Hönerlage, Jonah Shaver, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), The Smalley Institute for Nanoscale Science and Technology, Rice University [Houston], Department of Chemistry, NanoCarbon Center, lp2n-01,lp2n-12, and Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Exciton, Binding energy, Population, Aucun, FOS: Physical sciences, 02 engineering and technology, Carbon nanotube, 01 natural sciences, law.invention, Condensed Matter::Materials Science, law, 0103 physical sciences, Bound state, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 010306 general physics, Absorption (electromagnetic radiation), education, Biexciton, Condensed Matter::Quantum Gases, education.field_of_study, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter::Other, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 3. Good health, Electronic, Optical and Magnetic Materials, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Atomic physics, Trion, 0210 nano-technology
Abstract

We present a study of free carrier photo-generation and multi-carrier bound states, such as biexcitons and trions (ionized excitons), in semiconducting single-walled carbon nanotubes. Pump-and-probe measurements performed with fs pulses reveal the effects of strong Coulomb interactions between carriers on their dynamics. Biexciton formation by optical transition from exciton population results in an induced absorption line (binding energy 130 meV). Exciton-exciton annihilation process is shown to evolve at high densities towards an Auger process that can expel carriers from nanotubes. The remaining carriers give rise to an induced absorption due to trion formation (binding energy 190 meV). These features show the dynamics of exciton and free carriers populations., Comment: 9 Pages, 7 figures

Published
2013
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43. Tunable electronic correlation effects in nanotube-light interactions

Author

Vasili Perebeinos, Zhengyi Zhang, Stéphane Berciaud, Yuhei Miyauchi, Yuh Tomio, Hidekatsu Suzuura, Mitsuhide Takekoshi, James Hone, Chenguang Lu, Vikram Deshpande, Tony F. Heinz, and Philip Kim

Subjects
Nanotube, Condensed Matter - Materials Science, Materials science, Electronic correlation, Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, Doping, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Carbon nanotube, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, law.invention, Optical properties of carbon nanotubes, Optical phenomena, Condensed Matter::Materials Science, law, Chemical physics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), Optoelectronics, Charge carrier, business, Electrical tuning
Abstract

Electronic many-body correlation effects in one-dimensional (1D) systems such as carbon nanotubes have been predicted to modify strongly the nature of photoexcited states. Here we directly probe this effect using broadband elastic light scattering from individual suspended carbon nanotubes under electrostatic gating conditions. We observe significant shifts in optical transition energies, as well as line broadening, as the carrier density is increased. The results demonstrate the differing role of screening of many-body electronic interactions on the macroscopic and microscopic length scales, a feature inherent to quasi-1D systems. Our findings further demonstrate the possibility of electrical tuning of optical transitions and provide a basis for understanding of various optical phenomena in carbon nanotubes and other quasi-1D systems in the presence of charge carrier doping., Comment: 18 pages, 4 figures, plus supplemental material of 11 pages and 3 figures

Published
2013
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44. Epitaxy of MgO magnetic tunnel barriers on epitaxial graphene

Author

D. Halley, Yves Henry, Florian Godel, Stéphane Berciaud, D. Vignaud, Emmanuelle Pichonat, Hicham Majjad, Jean-Francois Dayen, Dominik Metten, Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), 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), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)

Subjects
Materials science, Bioengineering, Nanotechnology, 02 engineering and technology, Epitaxy, 01 natural sciences, law.invention, law, 0103 physical sciences, General Materials Science, Dewetting, Electrical and Electronic Engineering, 010306 general physics, Quantum tunnelling, Spintronics, Graphene, business.industry, Mechanical Engineering, General Chemistry, 021001 nanoscience & nanotechnology, Ferromagnetism, Mechanics of Materials, Optoelectronics, 0210 nano-technology, business, Graphene nanoribbons, Molecular beam epitaxy
Abstract

Epitaxial growth of electrodes and tunnel barriers on graphene is one of the main technological bottlenecks for graphene spintronics. In this paper, we demonstrate that MgO(111) epitaxial tunnel barriers, one of the prime candidates for spintronic application, can be grown by molecular beam epitaxy on epitaxial graphene on SiC(0001). Ferromagnetic metals (Fe, Co, Fe20Ni80) were epitaxially grown on top of the MgO barrier, thus leading to monocrystalline electrodes on graphene. Structural and magnetic characterizations were performed on these ferromagnetic metals after annealing and dewetting: they form clusters with a 100 nm typical lateral width, which are mostly magnetic monodomains in the case of Fe. This epitaxial stack opens the way to graphene spintronic devices taking benefits from a coherent tunnelling current through the epitaxial MgO/graphene stack.

Published
2013
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45. Front Cover: All-optical structure assignment of individual single-walled carbon nanotubes from Rayleigh and Raman scattering measurements (Phys. Status Solidi B 12/2012)

Author

James Hone, Stéphane Berciaud, Robert Caldwell, Tony F. Heinz, Vikram Deshpande, Philip Kim, Christophe Voisin, and Yuhei Miyauchi

Subjects
Chemistry, Nanotechnology, Carbon nanotube, Condensed Matter Physics, Molecular physics, Electronic, Optical and Magnetic Materials, law.invention, All optical, symbols.namesake, Front cover, law, symbols, Rayleigh scattering, Raman scattering
Published
2012
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46. Excitonic signatures in the optical response of single-wall carbon nanotubes

Author

Tony F. Heinz, Christophe Voisin, Hugen Yan, Guillaume Cassabois, Philippe Roussignol, James Hone, Sébastien Berger, Jean-Sébastien Lauret, Stéphane Berciaud, Laboratoire Pierre Aigrain (LPA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Departments of Physics and Electrical Engineering, Columbia University [New York], Laboratoire de Photonique Quantique et Moléculaire (LPQM), École normale supérieure - Cachan (ENS Cachan)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Laboratoire Charles Coulomb (L2C), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Department of Mechanical Engineering, Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Photoluminescence, Materials science, Exciton, Binding energy, 02 engineering and technology, Carbon nanotube, 01 natural sciences, law.invention, Condensed Matter::Materials Science, symbols.namesake, law, 0103 physical sciences, Rayleigh scattering, 010306 general physics, ComputingMilieux_MISCELLANEOUS, Condensed matter physics, Condensed Matter::Other, Graphene, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Optical properties of carbon nanotubes, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], symbols, Ballistic conduction in single-walled carbon nanotubes, 0210 nano-technology
Abstract

The optical properties of single-wall carbon nanotubes (SWNTs) are dominated by the excitonic character of the transitions even at room temperature. The very peculiar properties of these excitons arise from both the one-dimensional (1D) nature of carbon nanotubes and from the electronic properties of graphene from which nanotubes are made. We first propose a brief qualitative review of the structure of the excitonic manifold and emphasize the role of dark states. We describe recent experimental investigations of this excitonic structure by means of temperature dependent PL measurements. We investigate the case of upper sub-bands and show that high-order optical transitions remain excitonic for large diameter nanotubes. A careful investigation of Rayleigh scattering spectra at the single nanotube level reveals clear exciton–phonon side-bands and Lorentzian line profiles for all semi-conducting nanotubes. In contrast, metallic nanotubes show an ambivalent behavior which is related to the reduced excitonic binding energy. Schematic of the exciton manifold in single-wall carbon nanotubes.

Published
2012
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47. High-resolution spatial mapping of the temperature distribution of a Joule self-heated graphene nanoribbon

Author

Melinda Y. Han, Kwang S. Kim, Alexandru B. Georgescu, Young-Jun Yu, Stéphane Berciaud, Tony F. Heinz, Philip Kim, and Louis E. Brus

Subjects
Materials science, Physics and Astronomy (miscellaneous), Condensed Matter - Mesoscale and Nanoscale Physics, business.industry, Graphene, Aucun, Joule, FOS: Physical sciences, Hot spot (veterinary medicine), Scanning gate microscopy, Scanning thermal microscopy, law.invention, Scanning probe microscopy, symbols.namesake, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), symbols, Optoelectronics, business, Raman spectroscopy, Graphene nanoribbons
Abstract

We investigate the temperature distributions of Joule self-heated graphene nanoribbons (GNRs) with a spatial resolution finer than 100 nm by scanning thermal microscopy (SThM). The SThM probe is calibrated using the Raman G mode Stokes/anti-Stokes intensity ratio as a function of electric power applied to the GNR devices. From a spatial map of the temperature distribution, heat dissipation and transport pathways are investigated. By combining SThM and scanning gate microscopy data from a defected GNR, we observe hot spot formation at well-defined, localized sites., 4 pages, 3 figures, accepted on App. Phys. Lett

Published
2011

48. All-optical trion generation in single walled carbon nanotubes

Author

Bertrand Yuma, Laurent Cognet, Silvia M. Santos, Brahim Lounis, Pierre Gilliot, Jonah Shaver, Stéphane Berciaud, Mathieu Gallart, lp2n-01,lp2n-12, Laboratoire Photonique, Numérique et Nanosciences (LP2N), Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut d'Optique Graduate School (IOGS)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, and Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)

Subjects
Materials science, Exciton, Binding energy, Aucun, FOS: Physical sciences, General Physics and Astronomy, 02 engineering and technology, Carbon nanotube, 01 natural sciences, law.invention, Condensed Matter::Materials Science, law, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, Physics::Atomic and Molecular Clusters, 010306 general physics, Absorption (electromagnetic radiation), Condensed Matter::Quantum Gases, [PHYS.PHYS.PHYS-OPTICS]Physics [physics]/Physics [physics]/Optics [physics.optics], Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter::Other, 021001 nanoscience & nanotechnology, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Atomic physics, Trion, 0210 nano-technology, Luminescence, Chirality (chemistry), Excitation
Abstract

We present evidence of all optical trion generation and emission in undoped single walled carbon nanotubes (SWCNTs). Luminescence spectra, recorded on individual SWCNTs over a large CW excitation intensity range, show trion emission peaks red-shifted with respect to the bright exciton peak. Clear chirality dependence is observed for 22 separate SWCNT species, allowing for determination of electron-hole exchange interaction and trion binding energy contributions. Luminescence data together with ultrafast pump probe experiments on chirality sorted bulk samples suggest that exciton-exciton annihilation processes generate dissociated carriers that allow for trion creation upon a subsequent photon absorption event., 13 pages, 4 figures

Published
2011
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49. Low Bias Electron Scattering in Structure-Identified Single Wall Carbon Nanotubes: Role of Substrate Polar Phonons

Author

James Hone, Vasili Perebeinos, Stéphane Berciaud, Philip Kim, Jyoti Katoch, Tony F. Heinz, Bhupesh Chandra, and Masa Ishigami

Subjects
Nanotube, Materials science, Condensed matter physics, Phonon, Scattering, General Physics and Astronomy, Substrate (electronics), Carbon nanotube, Nitride, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, law.invention, Condensed Matter::Materials Science, Electrical resistivity and conductivity, law, Electron scattering
Abstract

We have performed temperature-dependent electrical transport measurements on known structure single wall carbon nanotubes at low bias. The experiments show a superlinear increase in nanotube resistivity with temperature, which is in contradiction with the linear dependence expected from nanotube acoustic-phonon scattering. The measured electron mean free path is also much lower than expected, especially at medium to high temperatures ($g100\text{ }\text{ }\mathrm{K}$). A theoretical model that includes scattering due to surface polar phonon modes of the substrates reproduces the experiments very well. The role of surface phonons is further confirmed by resistivity measurements of nanotubes on aluminum nitride.

Published
2011
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50. Temperature dependence of the anharmonic decay of optical phonons in carbon nanotubes and graphite

Author

Hugen Yan, Tony F. Heinz, Ioannis Chatzakis, Daohua Song, and Stéphane Berciaud

Subjects
Condensed Matter - Materials Science, Materials science, Phonon, Anharmonicity, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Carbon nanotube, Atmospheric temperature range, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, law.invention, Optical properties of carbon nanotubes, Condensed Matter::Materials Science, symbols.namesake, law, Femtosecond, symbols, Graphite, Atomic physics, Raman scattering
Abstract

We report on the temperature dependence of the anharmonic decay rate of zone-center (G mode) optical phonons in both single-walled carbon nanotubes and graphite. The measurements are performed using a pump-probe Raman scattering scheme with femtosecond laser pulses. For nanotubes, measured over a temperature range of 6 K-700 K, we observe little temperature dependence of the decay rate below room temperature. Above 300 K, the decay rate increases from 0.8 to 1.7 ps-1. The decay rates observed for graphite range from 0.5 to 0.8 ps-1 for temperatures from 300 K-700 K. We compare the behavior observed in carbon nanotubes and graphite and discuss the implications of our results for the mechanism of the anharmonic decay of optical phonons in both systems., 21 pages, 3 figures

Published
2011
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