The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
E Ikenaga - One of the best experts on this subject based on the ideXlab platform.
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mn incorporation into the Gaas Lattice investigated by hard x ray photoelectron spectroscopy and diffraction
Physical Review B, 2011Co-Authors: I Bartos, M. Cukr, Masaaki Kobata, Kiyoshi Kobayashi, P Jiřicek, Takeharu Sugiyama, E IkenagaAbstract:(Received 22 December 2010; revised manuscript received 31 March 2011; published 15 June 2011) Photoelectron spectroscopy and diffraction have been used to investigate structural changes during the annealing process of Ga1−xMnxAs samples. Hard x-ray radiation helped in observing photoelectron core-level spectra and electron diffraction from the bulk underlying the oxidized surface layer. High electron-energy resolution enabled us to separate the components due to substitutional and interstitial Mn atoms in the intrinsic Mn 2p3/2 photoemission profile, resulting in two peaks at 638.8 and 639.5 eV binding energy, respectively. The peaks display the known characteristic behavior after annealing, that is, an almost complete reduction of the interstitial component and preservation of the substitutional component. In the photoelectron diffraction, a sensitivity of high-energy polar plots to the incorporation sites of photoemitting atoms into the atomic Lattice has been shown. As a consequence, the experimental polar plots from substitutional and interstitial Mn atoms, which are supported theoretically, show characteristic features that provide structural information. From the similarities and differences of the polar plots for Mn and Ga, we have confirmed the assignment of components within the intrinsic part of the photoemission Mn 2p3/2 signal suggested by photoelectron spectroscopy.
Valder N. Freire - One of the best experts on this subject based on the ideXlab platform.
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Resonant peaks in the transmission coefficient of compositionally nonabrupt Gaas/AlxGa1−xAs heterojunctions
Superlattices and Microstructures, 2003Co-Authors: Valder N. Freire, G. A. FariasAbstract:Abstract The transmission coefficient of compositionally nonabrupt Gaas/Al x Ga 1−x As heterojunctions is calculated. A linear aluminium molar fraction variation in the interface width l is assumed. Numerical results are obtained for electrons and holes, corresponding to observed transmission resonant peaks for l as short as two Gaas Lattice parameters.
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Energy level splitting in doped nonabrupt double quantum well
Solid State Communications, 1998Co-Authors: J. A. K. Freire, G. A. Farias, Valder N. FreireAbstract:Abstract The electron energy levels of doped nonabrupt Gaas Al x Ga 1−x As double quantum wells are calculated. It is shown that their characteristic splitting is reduced considerably when interface widths of only two Gaas Lattice units are considered. The nonabrupt interfaces shift the energy levels toward high energies. The energy level shift and splitting are sensitive to the level of doping.
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Electron Transmission Through Nonabrupt Gaas/AlxGa1-xAs Double-Barriers Subjected to an Electric Field
Brazilian Journal of Physics, 1997Co-Authors: M.consuelo A. Lima, G. A. Farias, Valder N. FreireAbstract:It is shown that the existence of nonabrupt interfaces modify electric field effects on the electron transmission through a Gaas/AlxGa1-xAs double-barrier. When the applied electric intensity is 25 kV/cm, and the abrupt well and barriers are 100 A wide, interfaces as thin as two Gaas Lattice parameters are responsible for shifts at least of 10 meV in the electron tunneling resonance energies. The type of interface potential and electron effective mass description changes significantly theoretical results related to the electric field influence on the electron transmission properties.
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Interface effects in the high electric field resonances of single AlxGa1-xAs non-abrupt barriers in Gaas
Superlattices and Microstructures, 1995Co-Authors: M.consuelo A. Lima, G. A. Farias, Valder N. FreireAbstract:Abstract The influence of nonabrupt interfaces in the high electric field resonances of single Al x Ga 1- x As barriers in Gaas is studied. The resonances are considerably smoothed when interfacial widths are as small as two Gaas Lattice parameters. Several resonances in the transmission coefficient of a 0.154 eV electron through a non-abrupt Al x Ga 1- x As single barrier in Gaas, with height of 240 meV and 200 A of width, can even disappear if interfacial widths of four Gaas Lattice parameters are considered. Interface effects are shown to be more important for heavy holes than for electrons.
Masaaki Tanaka - One of the best experts on this subject based on the ideXlab platform.
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local structures of iii v diluted magnetic semiconductors ga 1 x mn x as studied using extended x ray absorption fine structure
Physical Review B, 1998Co-Authors: R Shioda, K Ando, Toshiaki Hayashi, Masaaki TanakaAbstract:Local structures around Mn in ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ ($x=0.005$ and 0.074) films have been studied using Mn $K$-edge extended x-ray-absorption fine structure. In the ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ films, Mn atoms are substituted into the Ga sites in the zinc-blende-type Gaas Lattice. The Mn-As bond length (2.49\char21{}2.50 \AA{}) in ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ is 2\char21{}3 % larger than the Ga-As bond length (2.44 \AA{}) in bulk Gaas. The longer Mn-As bonds cause local disorder in the Gaas Lattice, the degree of which increases with the Mn composition.
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Local structures of III-V diluted magnetic semiconductors Ga 1 − x Mn x As studied using extended x-ray-absorption fine structure
Physical Review B, 1998Co-Authors: R Shioda, K Ando, Toshiaki Hayashi, Masaaki TanakaAbstract:Local structures around Mn in ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ ($x=0.005$ and 0.074) films have been studied using Mn $K$-edge extended x-ray-absorption fine structure. In the ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ films, Mn atoms are substituted into the Ga sites in the zinc-blende-type Gaas Lattice. The Mn-As bond length (2.49\char21{}2.50 \AA{}) in ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ is 2\char21{}3 % larger than the Ga-As bond length (2.44 \AA{}) in bulk Gaas. The longer Mn-As bonds cause local disorder in the Gaas Lattice, the degree of which increases with the Mn composition.
A B Smirnov - One of the best experts on this subject based on the ideXlab platform.
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nitrogen incorporation into Gaas Lattice as a result of the surface cavitation effect
Journal of Physics D, 2010Co-Authors: R K Savkina, A B SmirnovAbstract:Semi-insulating gallium arsenide was exposed to cavitation impact initiated by focusing a high-frequency acoustic wave into liquid nitrogen. Optical and atomic force microscopy methods were used for the analysis of surface morphology. Formation of microstructures as well as change in the chemical composition of the surface are observed. The morphology of the structures is highly dependent on the acoustic parameters. Raman spectroscopy data have confirmed the incorporation of nitrogen atoms into the Gaas Lattice and Ga–N bond formation in the region of maximal structural change due to the cavitation impact.
Josep Penuelas - One of the best experts on this subject based on the ideXlab platform.
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Gaas Core/SrTiO3 Shell Nanowires Grown by Molecular Beam Epitaxy
Nano Letters, 2017Co-Authors: Xin Guan, Jeanne Becdelievre, Benjamin Meunier, Nicholas Blanchard, X. Jaurand, Romain Bachelet, Claude Botella, Philippe Regreny, Guillaume Saint-girons, Abderraouf Benali, Mathieu Silly, Nicolas Chauvin, Geneviève GRENET, Fausto Sirotti, Michel Gendry, Josep PenuelasAbstract:We have studied the growth of a SrTiO3 shell on self-catalyzed Gaas nanowires grown by vapor-liquid-solid assisted molecular beam epitaxy on Si(111) substrates. To control the growth of the SrTiO3 shell, the Gaas nanowires were protected using an arsenic capping/decapping procedure in order to prevent uncontrolled oxidation and/or contamination of the nanowire facets. Reflection high energy electron diffraction, scanning electron microscopy, transmission electron microscopy and x-ray photoelectron spectroscopy were performed to determine the structural, chemical and morphological properties of the heterostructured nanowires. Using adapted oxide growth conditions, it is shown that most of the perovskite structure SrTiO3 shell appears to be oriented with respect to the Gaas Lattice. These results are promising for achieving one-dimensional epitaxial semiconductor core / functional oxide shell nanostructures.
