A5005397565- Semiconductor Quantum Structures and Devices
- Nanowire Synthesis and Applications
- Advanced Semiconductor Detectors and Materials
- Semiconductor materials and interfaces
- GaN-based semiconductor devices and materials
- Semiconductor materials and devices
- Photonic and Optical Devices
- Semiconductor Lasers and Optical Devices
- Chalcogenide Semiconductor Thin Films
- Integrated Circuits and Semiconductor Failure Analysis
- Quantum Dots Synthesis And Properties
- Silicon and Solar Cell Technologies
- solar cell performance optimization
- nanoparticles nucleation surface interactions
- Thin-Film Transistor Technologies
- Nanotechnology research and applications
- Advancements in Semiconductor Devices and Circuit Design
- Theoretical and Computational Physics
- Surface and Thin Film Phenomena
- Rare-earth and actinide compounds
- Electron and X-Ray Spectroscopy Techniques
- Iron-based superconductors research
- Electronic and Structural Properties of Oxides
- Gold and Silver Nanoparticles Synthesis and Applications
- Silicon Nanostructures and Photoluminescence
Centre d’Élaboration de Matériaux et d’Études Structurales
2015-2024
Interface (United States)
2016-2023
Université de Toulouse
2010-2020
Université Toulouse III - Paul Sabatier
2010-2020
Centre National de la Recherche Scientifique
2007-2020
Université de Rennes
2016
Universidad de Zaragoza
2015
CEA Grenoble
1989-1990
Using the strained-induced 2D–3D transition, InAs dots have been grown on InP(001) and examined by transmission electron microscopy. Two different modes of island size spatial distribution identified. For deposit 1.5 1.8 monolayers, islands are about 7 nm high randomly distributed. Above 2 they five times smaller in volume locally self-organized, with a typical distance 40 independent density. It is suggested that strong dependence total amount deposited mainly due to long range interactions...
In the context of advanced photonics or photovoltaics, monolithic integration high-quality III-V materials as near possible to Si substrate is great interest. Here, authors experimentally and theoretically clarify III-V/Si crystal growth processes. Monodomain 3D islands are observed at early stages AlSb, AlN, GaP epitaxy on Si, independently misfit. It shown that complete wetting cannot be achieved in most systems. Surface/interface contributions free energy variations found prominent over...
Fe–Au core–shell nanoparticles displaying an original polyhedral morphology have been successfully synthesized through a physical route. Analyses using transmission electron microscopy show that the Au shell forms truncated pyramids epitaxially grown on (100) facets of iron cubic core. The evolution elastic energy and strain field in as function their geometry composition is calculated finite-element method. stability remarkable centered experimentally observed attributed to weak resulting...
Compressive GaInAsP multiple quantum wells (MQW) grown by gas source molecular-beam epitaxy present altered structural and optical characteristics when tensile barriers are used instead of lattice-matched ones. An alternate tensile/compressive MQW has been examined transmission electron microscopy. A strong lateral modulation thickness, strain, probably chemical composition was shown. This exhibits pronounced anisotropy, with a periodicity about 50 nm along the [110] direction. Although its...
Here we clarify the central role of miscut during group III-V/group IV crystal growth. We show that impacts initial antiphase domain distribution, with two distinct nucleation-driven (miscut typically >1\ifmmode^\circ\else\textdegree\fi{}) and terraces-driven 0.1\ifmmode^\circ\else\textdegree\fi{}) regimes. It is then inferred how distribution mean phase lateral length are affected by miscut. An experimental confirmation given through comparison distributions in GaP GaSb/AlSb samples grown...
We report on the synthesis of InAs quantum dots (311)B InP substrates. It is found that use such high index surfaces allows formation a density (5×1010 islands/cm2) small islands (diameter≈350 Å) InP. Moreover, large improvement size uniformity obtained in comparison with deposition (100) surface. The standard height deviations are ±13% and ±50% for grown surfaces, respectively. Then, we show modification As/P flux sequences, after island formation, permits control dot emission wavelength....
Raman scattering has been used to investigate strained InAs islands grown on InP(001), in correlation with transmission electron microscopy. Symmetry arguments, selective resonance at the E1-like transition and comparison a single-quantum-well structure allowed distinguish between remaining wetting layer signals. Whereas vibrational modes of 2D thin layers are greatly affected by interface roughness confinement, strain effects mainly account for phonon frequency shifts islands.
Zero-net strained multilayer alternating tensile GaInP and compressive InAsP have been grown on (001)InP by metal-organic vapor-phase epitaxy. A structural analysis using transmission electron microscopy (TEM) is reported. remarkably regular laterally modulated structure has observed. GaInP- InAsP-rich vertical zones alternate with a periodicity of 0.28 μm along the lateral [110] direction, thus balancing mismatch rather than [001] growth direction. TEM experiments suggest that each zone...
We report a structural study of molecular beam epitaxy-grown lattice-matched GaP/Si(0 0 1) thin layers with an emphasis on the interfacial properties, and optical studies GaAsP(N)/GaP(N) quantum wells coherently grown onto GaP/Si pseudo substrates, through complementary set characterization tools. Room temperature photoluminescence at 780 nm from (GaAsPN/GaPN) silicon substrate is reported. Despite this good property, time-resolved measurements demonstrate clear influence non-radiative...
We have used reflection high-energy electron diffraction (RHEED) and x-ray to study the growth of CdTe/Cd0.90 Zn0.10 Te (001) heterostructures by molecular beam epitaxy (MBE). A process involving an excess Cd interruptions at well-barrier interfaces has been found necessary observe strong persistent RHEED oscillations during quantum wells superlattices. This method gives accurate in situ thickness measurements all layers superlattices, good agreement with data. The sharpness satellites...
We report the demonstration of an ultra-sensitive Raman probing single GaN/AlN nanowires (NWs). The high sensitivity scattering by longitudinal optical phonon is achieved using ultraviolet resonant excitation near energy band-gap GaN. Structural variations within one nanowire are evidenced very accurately strong LO phonons shifts in UV spectra recorded on different regions NW. They interpreted as a fine double strain state experienced GaN, due to formation AlN shell bottom part core-shell...
Abstract This work shows that a large‐scale textured GaP template monolithically integrated on Si can be developed by using surface energy engineering, for water‐splitting applications. The stability of (114)A facets is first shown, based scanning tunneling microscopy images, transmission electron microscopy, and atomic force microscopy. These observations are then discussed in terms thermodynamics through density functional theory calculations. A stress‐free nanopatterned obtained molecular...
The electrical resistivity and high-field magnetoresistance of the heavy-fermion compound ${\mathrm{CeRu}}_{2}$${\mathrm{Si}}_{2}$ have been measured as a function pressure up to 10 kbar. From depression ${T}^{2}$ term below \ensuremath{\approxeq}1 K, rapid increase characteristic energy quasiparticle system is inferred, which can be represented by large electronic Gr\"uneisen coefficient \ensuremath{\Omega}\ensuremath{\simeq}185, in excellent agreement with other experimental estimates. It...
In the fight against antibiotic resistance, gold nanoparticles (AuNP) with antibiotics grafted on their surfaces have been found to be potent agents. Ampicillin-conjugated AuNPs thus reported overcome highly ampicillin-resistant bacteria. However, structure at atomic scale of these hybrid systems remains misunderstood. this paper, interface between an ampicillin molecule AMP and three flat facets Au(111), Au(110) Au(100) has investigated numerical simulations (dispersion-corrected DFT)....
We have grown GaAsBi quantum wells by molecular beam epitaxy. studied the properties of a 7% Bi well and their variation with thermal annealing. High-resolution X-ray diffraction, secondary ion mass spectrometry, transmission electron microscopy been employed to get some insight into its structural properties. Stationary time-resolved photoluminescence shows that emission, peaking at 1.23 μm room temperature, can be improved rapid annealing 650°C, while use higher temperature leads emission...
Structural and chemical properties of InAs/AlSb interfaces have been studied by transmission electron microscopy. multilayers were grown molecular beam epitaxy with different growth sequences at interfaces. The out-of-plane strain, determined using high resolution microscopy geometrical phase analysis, has related to the composition analyzed angle annular dark field imaging. Considering local strain chemistry, we estimated interface discussed mechanisms formation for sequences. In...
Spontaneously formed Al-As type interfaces of the InAs/AlSb system grown by molecular beam epitaxy for quantum cascade lasers were investigated atomic resolution scanning transmission electron microscopy. Experimental strain profiles compared to those coming from a model structure. High negative out-of-plane strains with same order magnitude as perfect observed. The effects geometrical phase analysis used determination evidenced and discussed in case abrupt huge variations both composition...
We propose a novel phase-matching scheme in GaP whispering-gallery-mode microdisks grown on Si substrate combining modal and 4¯ -quasi-phase-matching for second-harmonic-generation. The technique consists unlocking parity-forbidden processes by tailoring the antiphase domain distribution layer. Our proposal can be used to overcome limitations of form birefringence using high order whispering-gallery-modes. frequency conversion efficiency this new demonstrates competitiveness nonlinear...
While combining two metals in the same nanoparticle can lead to remarkable novel applications, resulting structure terms of crystallinity and shape remains difficult predict. It is thus essential provide a detailed atomistic picture underlying growth processes. In present work we address case core-shell Fe-Au Fe-Ag nanoparticles. Interface properties between Fe noble Au Ag, computed using DFT, were used parameterize pairwise interactions combination with available many-body potentials for...
Abstract GaAsPN semiconductors are promising material for the development of high-efficiency tandem solar cells on silicon substrates. diluted-nitride alloy is studied as top-junction due to its perfect lattice matching with Si substrate and ideal bandgap energy allowing a current bottom cell. The GaP/Si interface also in order obtain defect-free pseudo-substrates suitable subsequent top junctions growth. Result shows that double-step growth procedure suppresses most microtwins bi-stepped...
The experimental island shapes of III–V islands grown on silicon (001) in the Volmer-Weber growth mode are analyzed frame theory wetting crystals. A reverse Wulff-Kaishew (or Winterbottom) construction is used order to access interfacial energy. We apply this approach AlSb and GaSb Si by molecular beam epitaxy observed scanning transmission electron microscopy. Experimental ratios between energies (001), (110), (111)A, (111)B surfaces established. Interface then quantitatively estimated for...