A5039930359- GaN-based semiconductor devices and materials
- Semiconductor materials and devices
- Metal and Thin Film Mechanics
- Ga2O3 and related materials
- ZnO doping and properties
- Semiconductor Quantum Structures and Devices
- Semiconductor materials and interfaces
- Advanced Semiconductor Detectors and Materials
- Silicon Carbide Semiconductor Technologies
- Copper-based nanomaterials and applications
- Acoustic Wave Resonator Technologies
- Catalytic Processes in Materials Science
- Ion-surface interactions and analysis
- Chalcogenide Semiconductor Thin Films
- Advancements in Semiconductor Devices and Circuit Design
- Electron and X-Ray Spectroscopy Techniques
- Nanowire Synthesis and Applications
- Boron and Carbon Nanomaterials Research
- Advanced Photocatalysis Techniques
- Catalysts for Methane Reforming
- Silicon and Solar Cell Technologies
- Gas Sensing Nanomaterials and Sensors
- Semiconductor Lasers and Optical Devices
- Catalysis and Oxidation Reactions
- Magnetic and transport properties of perovskites and related materials
Centre National de la Recherche Scientifique
2014-2024
Centre de Recherche sur les Ions, les Matériaux et la Photonique
2015-2024
École Nationale Supérieure d'Ingénieurs de Caen
2015-2024
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2014-2024
Université de Caen Normandie
1995-2024
Normandie Université
2024
Université de Lille
2014
Institut d'électronique de microélectronique et de nanotechnologie
2014
Laboratoire d'Etude et de Recherche sur le Matériau Bois
2011
Laboratoire de Physique Corpusculaire de Caen
1996-2010
An efficient preparation method, which provides wedge-shaped cross-section transmission electron microscopy samples, has been developed. It was then used to investigate the structure of as-deposited cobalt multilayers on silicon substrates by rf plasma sputtering. found that an extended reaction takes place between Co and Si probably during deposition. The atoms react with substrate form amorphous silicide layer. When deposited layer is <3 nm thick, it entirely reacts can as large 5...
Using high-resolution electron microscopy, anisotropic elasticity calculations, and image simulations, typical contrast was identified for the pure edge threading dislocations in GaN layers grown by molecular-beam epitaxy on sapphire. Their atomic structure found to exhibit 5/7, or 8 atom cycles. The two configurations were observed at a similar frequency isolated low-angle boundaries. Coincidence grain boundaries have been studied they are all made of pure-edge with above structures. A...
We have determined the main parameters of quasi-one-dimensional excitons confined in GaAs V-shaped quantum wires, namely exciton Bohr radius and binding energy, by two-photon absorption magnetoluminescence experiments. The experimental results are excellent agreement with our calculations, based on realistic wave functions for actual wire geometry.
Despite the development of high-resolution electron microscopy (HREM) that allows imaging most materials, extraction quantitative information at atomic scale still requires considerable additional efforts. This review presents recent developments on techniques can be used to determine local strain, chemical composition or structure retrieval in HREM. The source noise images and effective methods for improving signal-to-noise ratio direct Fourier space are discussed. artefacts filtering...
First-principles calculations, by means of the full-potential augmented plane wave method using local density approximation, were carried out for structural and electronic properties AlxGa1−xN, InxGa1−xN InxAl1−xN alloys in wurtzite structure. We have investigated lattice parameters band gap energies. The constants a c are found to change linearly AlxGa1−xN alloy, while both parameters, a, exhibit an upward bowing. calculated variation three downward bowing 0.71 eV, 1.7 eV 4.09 InxAl1−xN,...
Abstract Platinum and Gallium Arsenide reaction is a common issue for the stability of Pt-GaAs contacts, where formation different alloys during fabrication operation degrades performance devices. In this work, we have carried out in situ deposition Pt on GaAs InAlGaAs focused ion beam machine annealing high-resolution transmission electron microscope. The local strains were then determined using geometrical phase analysis technique various phases obtained by digital extraction lattice...
A diffraction analysis in the transmission electron microscope was carried out on InxGa1−xN layers grown (0001) sapphire by metalorganic vapor phase epitaxy top of thick GaN buffer layers. It is found that ternary can be chemically ordered. The In and Ga atoms occupy, respectively, two simple hexagonal sublattice sites related glide mirrors helicoidal axes P63 mc symmetry group wurtzite GaN. ordered subsequently lowered disappearance these operations, it shown to agree with P3ml space group.
Using strain analysis on high resolution electron microscopy images and finite element modeling of InGaN quantum wells (QWs), it is shown that the In composition changes inside layers can be accurately determined. The analyzed samples were nominally grown with 15%–17% by molecular beam or metalorganic vapor phase epitaxy. Inside these QWs, not homogeneous. Finite strongly suggests measured corresponds most probably to InN clusters whose size depends growth method.
Transmission electron microscopy and KOH etching were used to determine the structure of carrot defect in 4H-SiC epilayers. The consists two intersecting planar faults on prismatic {11¯00} basal {0001} planes. Both are connected by a stair-rod dislocation with Burgers vector 1∕n [101¯0] n>3 at crossover. A Frank-partial b=1∕12[44¯03] terminates fault.
The formation of the ${12\ifmmode\bar\else\textasciimacron\fi{}10}$ stacking fault, which has two atomic configurations in wurtzite (Ga,Al,In)N, been investigated by high-resolution electron microscopy and energetic calculations. It originates from steps at SiC surface it can form on a flat (0001) sapphire surface. A modified Stillinger-Weber potential is used order to investigate relative stability have comparable energy AIN, whereas...
Abstract A procedure based on the stacking sequences of semiconducting materials structures is proposed in order to determine possible dislocation character interface steps between two different polytypes. It next applied 2H and 3C, 4H 6H Three dislocations are found with ⅙〈2023〉, ⅓〈1010〉 ½〈0001〉 Burgers vectors. In a high-resolution electron microscopy study particular case 2H-AlN/6H-SiC, only kinds step could be observed. This agreement assumption that growth AlN systematically starts at...
First-principles calculations have been used to study the effect of vacancies on structural and electronic properties in substoichiometric TiCx TiNx. The equilibrium volumes, bulk moduli, band structures density states phases was studied using a full-potential linear augmented plane-wave method. A model structure eight-atom supercells with ordered within carbon nitrogen sublattices is used.
Epitaxial GaN layers grown on sapphire contain a very large density of defects (threading dislocations, stacking faults, inversion domain boundaries, . .). Among these defects, we have performed the analysis basal faults by high resolution transmission electron microscopy. Two I1 and I2, were identified. The formation fault is based climb-dissociation process (1/3)⟨11-20⟩ or [0001] perfect dislocations whereas I2 due to shear structure leading partial dislocation loop.
Using high resolution electron microscopy and extensive image simulation, the atomic structure of inversion boundaries has been determined in GaN layers grown on sapphire by cyclotron resonance assisted molecular beam epitaxy. They form nanometric domains (5–20 nm) limited {101̄0} planes crossing whole epitaxial layer. These small dimensions excluded use more conventional methods such as convergent diffraction for their characterization. For simulations, up to 10 models including well known...
The crystallographic nature of the damage created in GaN by 300keV rare earth ions has been investigated following implantation at room temperature varying fluence Er, Eu, or Tm from 7×1013to2×1016at.∕cm2. There is a build up point defects clusters, which increases density and depth versus ion fluence. When threshold around 3×1015at.∕cm2 reached, nanocrystalline surface layer observed. From lowest fluence, we out formation basal stacking faults, with majority I1. Their also but it seen to...
The authors report on the plasma-assisted molecular-beam epitaxy of semipolar AlN(112¯2) films (11¯00) m-plane sapphire. AlN deposited m sapphire settles into two main crystalline orientation domains, and AlN(101¯0), whose ratio depends III/V ratio. in-plane epitaxial relationships are [112¯3¯]AlN‖[0001]sapphire [11¯00]AlN‖[112¯0]sapphire. In case were [12¯10]AlN‖[0001]sapphire [0001]AlN‖[112¯0]sapphire. Growth under moderate nitrogen-rich conditions enables them to isolate (112¯2) improve...
published or not.The documents may come from teaching and research institutions in France abroad, public private centers.
At low fluence, 300 keV Eu implantation in GaN leads to a strain increase followed by saturation as observed X-ray diffraction, while Rutherford backscattering/channeling remains insensitive the radiation damage. Based on transmission electron microscopy, this regime is attributed damaged region crystal bulk which interaction between point defects and stacking faults (SFs) occurs, leading densification of network planar trapping defects. higher fluences, above 2×1014 Eu/cm2, evolutions state...