A5012609449- Diamond and Carbon-based Materials Research
- Graphene research and applications
- Semiconductor materials and devices
- Metal and Thin Film Mechanics
- 2D Materials and Applications
- Boron and Carbon Nanomaterials Research
- GaN-based semiconductor devices and materials
- Electronic and Structural Properties of Oxides
- Semiconductor Quantum Structures and Devices
- Ion-surface interactions and analysis
- High-pressure geophysics and materials
- ZnO doping and properties
- Ga2O3 and related materials
- Advanced Fiber Laser Technologies
- Force Microscopy Techniques and Applications
- MXene and MAX Phase Materials
- Perovskite Materials and Applications
- Advanced Materials Characterization Techniques
- Nanowire Synthesis and Applications
- Advanced Surface Polishing Techniques
- Semiconductor Lasers and Optical Devices
- Molecular Junctions and Nanostructures
- Advanced Semiconductor Detectors and Materials
- Photonic and Optical Devices
- Quantum and electron transport phenomena
Groupe d’Étude de la Matière Condensée
2015-2024
Université Paris-Saclay
2015-2024
Centre National de la Recherche Scientifique
2015-2024
Université de Versailles Saint-Quentin-en-Yvelines
2015-2024
National Institute for Materials Science
2019
Gesellschaft für Mikroelektronikanwendung Chemnitz (Germany)
2016-2017
Université de Strasbourg
2010
Institut de Physique
2010
European Automobile Manufacturers Association
2010
CEA LIST
2010
We present an overview of the main techniques for production and processing graphene related materials (GRMs), as well key characterization procedures. adopt a 'hands-on' approach, providing practical details procedures derived from literature authors' experience, in order to enable reader reproduce results.
Abstract Single photon emitters (SPEs) in low-dimensional layered materials have recently gained a large interest owing to the auspicious perspectives of integration and extreme miniaturization offered by this class materials. However, accurate control both spatial location emission wavelength quantum is essentially lacking date, thus hindering further technological steps towards scalable photonic devices. Here, we evidence SPEs high purity synthetic hexagonal boron nitride (hBN) that can be...
Cathodoluminescence and photoluminescence spectroscopies have been performed on hexagonal boron nitride powders. The combination of these techniques allows us to analyze the two observed luminescence bands. A deep-level UV emission at about $4\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ is attributed defects or impurities, a near-band-gap $5.5\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$. band composed four peaks, which are phonon replica due localized vibrations. In region, six components between 5.2...
A quantitative analysis of the excitonic luminescence efficiency in hexagonal boron nitride (h-BN) is carried out by cathodoluminescence ultraviolet range and compared with zinc oxide diamond single crystals. high quantum yield value ∼50% found for h-BN at 10 K comparable to that direct band-gap semiconductors. This bright 215 nm remains stable up room temperature, evidencing strongly bound character excitons bulk h-BN. Ab initio calculations exciton dispersion confirm indirect nature...
Hexagonal boron nitride (hBN) has recently gained a strong interest as strategic component in engineering van der Waals heterostructures built with two dimensional crystals such graphene. This work reports micro-Raman measurements on hBN flakes made of few atomic layers, prepared by mechanical exfoliation. The temperature dependence the Raman scattering is investigated first to define appropriate conditions suitable for thin layers avoiding undesirable heating induced effects. We further...
Understanding the surface properties of organic-inorganic lead-based perovskites is high importance to improve device's performance. Here, we have investigated differences between and bulk optical CH3NH3PbBr3 single crystals. Depth-resolved cathodoluminescence was used probe near-surface region on a depth few microns. In addition, studied transmitted luminescence through thicknesses 50 600 μm. both experiments, expected spectral shift due reabsorption effect has been precisely calculated. We...
Indistinguishable single photons are a key requirement for most applications in optical quantum information. However, this feature has remained elusive among two-dimensional materials, primarily due to insufficient coherence of emitters. Here the authors controllably generate spectrally narrow and stable single-photon source an h-BN crystal by electron-beam irradiation, demonstrate Hong-Ou-Mandel interference emitted photons, which is signature indistinguishability. These results enable...
Hexagonal boron nitride (h-BN) and graphite are structurally similar but with very different properties. Their combination in graphene-based devices is now of intense research focus, it becomes particularly important to evaluate the role played by crystalline defects on their In this paper, cathodoluminescence (CL) properties hexagonal crystallites reported compared those nanosheets mechanically exfoliated from them. First, link between presence structural recombination intensity trapped...
Hexagonal boron nitride (hBN) has regained interest as a strategic component in graphene engineering and van der Waals heterostructures built with two dimensional materials. It is crucial then, to handle reliable characterization techniques capable assess the quality of structural electronic properties hBN material used. We present here procedures based on optical spectroscopies, namely cathodoluminescence Raman, additional support analysis conducted by transmission electron microscopy. show...
The excitonic recombinations in hexagonal boron nitride (hBN) are investigated with spatially resolved cathodoluminescence spectroscopy the ultraviolet range. Cathodoluminescence images of an individual hBN crystallite reveals that 215 nm free line is quite homogeneously emitted along crystallite, whereas 220 and 227 emissions located specific regions crystallite. Transmission electron microscopy show these contain a high density crystalline defects. This suggests both produced by...
Individual multiwall boron nitride nanotubes with diameters from 30 nm to 110 are shown be efficient UV emitters by cathodoluminescence. Their luminescence does not evolve much in this diameter range, dominant recombinations at about 230 nm. As a result, single nanotube properties can obtained experiments performed on ensembles of nanotubes. Such studied photoluminescence as function temperature (5 K--300 K) and excitation 9 K. The results discussed compared the related bulk material,...
Abstract Near band gap photoluminescence (PL) of a hexagonal boron nitride single crystal has been studied at cryogenic temperatures with synchrotron radiation excitation. The PL signal is dominated by trapped‐exciton optical transitions, while the excitation (PLE) spectra show features assigned to free excitons. Complementary photoconductivity and PLE measurements set transition energy 6.4 eV Frenkel exciton binding larger than 380 meV. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Cathodoluminescence (CL) experiments at low temperature have been undertaken on various bulk and exfoliated hexagonal boron nitride (hBN) samples. Different crystals grown from different synthesis methods studied. All of them present the same so-called S series in 5.6–6 eV range, proving its intrinsic character. Luminescence spectra flakes containing 100 down to 6 layers recorded. Strong modifications UV range are observed discussed within general framework 2D exciton properties lamellar crystals.
High purity chemically vapor deposited (CVD) diamond single crystals are now widely available. However, the reduction of dislocations in this material still remains an important challenge that will strongly condition its adoption areas such as optics, electronics, and spintronics, where these defects have a disastrous effect on properties. In work we report methodology allows complete identification type, density, distribution high quality CVD crystal. A good agreement between all...
The ability to identify and characterize homogeneous inhomogeneous dephasing processes is crucial in solid-state quantum optics. In particular, spectral diffusion leading line broadening difficult evidence when the associated timescale shorter than inverse of photon detection rate. Here, we show that a combination resonant laser excitation second-order correlations allows access such fast dynamics. drive converts into intensity fluctuations, leaving signature coherence function...
In this article, the surfactant capability of for AlGaN growth by plasma-assisted molecular beam epitaxy has been assessed. We have determined range substrate temperatures and fluxes to form a self-regulated 1×1 adlayer on AlxGa1−xN(0001). The presence film favors two-dimensional under stoichiometric conditions. formation metal droplets surface is inhibited. incorporation, if any, lower than 0.01%. structural quality layers verified high-resolution x-ray diffraction, both in symmetric...
Abstract Optical properties of multiwall boron nitride nanotubes are investigated by means luminescence and absorption spectroscopies. Cathodoluminescence imaging shows that highly UV luminescent materials the is located all along nanotube. In comparison with related bulk material, hexagonal nitride, experiments point out role excitonic effects in this nanoobject. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The value of the impurity-to-band activation energy EA a dopant is basic feature electrical conductivity semiconductors. Various techniques were used to determine in n-type diamond doped with phosphorus, giving values varying from 0.43 eV 0.63 eV, 0.6 being commonly accepted for ionization phosphorus donors diamond. Nevertheless, up now, dispersion experimental remains unexplained. In this work, we investigate properties set homoepitaxial films different concentrations by Hall effect...
Among wide bandgap semiconductors, diamond presents physical properties particularly suited for high performance power electronic devices. Growth and doping of chemical vapor deposited (CVD) have been mainly optimized in the conventional (100) crystal orientation, highly studied on (111) surfaces recently initiated (113). This last orientation seems very promising, as is shown intrinsic p-type doped diamonds. In this work, we report growth CVD phosphorus films (113)-oriented substrates. The...
Excitonic recombinations are investigated by cathodoluminescence in a series of homoepitaxial diamond layers doped with boron the range $(2\ifmmode\times\else\texttimes\fi{}{10}^{16})$--$(5\ifmmode\times\else\texttimes\fi{}{10}^{18}) \mathrm{at} {\mathrm{cm}}^{\ensuremath{-}3}.$ As opposed to earlier observations made on polycrystalline boron-doped diamond, we show that ratio between neutral-boron bound exciton and free-exciton recombination intensities is proportional content up...
Abstract Homoepitaxial boron‐doped diamond layers grown by chemical vapor deposition on (100)‐oriented substrates are studied Hall effect and resistivity measurements as a function of the temperature. In range 140–600 K, hole concentration is well described neutrality equation in regime very low compensation, with characteristic E i /2 activation energy, where ionization energy boron acceptors. It indicates that residual donor extremely (<10 13 cm −3 ).