Raman scattering of the optical vibrational modes in (GaAs)n(AlAs)nsuperlattices grown on (311)Aand (311)Bsurfaces

1995 ◽  
Vol 51 (8) ◽  
pp. 5473-5476 ◽  
Author(s):  
Yu. A. Pusep ◽  
S. W. da Silva ◽  
J. C. Galzerani ◽  
D. I. Lubyshev ◽  
V. Preobrazhenskii ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Vibrational Modes

Raman scattering from sputtered films of YBa2Cu3Oy

1988 ◽  
Vol 66 (8) ◽  
pp. 695-699 ◽  
Author(s):  
J. Chrzanowski ◽  
J. C. Irwin ◽  
R. R. Parsons ◽  
P. J. Mulhern
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Magnetron Sputtering ◽  
Raman Scattering ◽  
Oxygen Content ◽  
High Temperature Superconductor ◽  
Superconducting Films ◽  
Vibrational Modes ◽  
Dc Magnetron Sputtering ◽  
Sputtered Films

Thin films of the high-temperature superconductor YBa2Cu3Oy have been deposited on Al2O3 and MgO substrates by dc magnetron sputtering. Raman-scattering experiments have been carried out on these films at various temperatures. The results of these experiments have been used to estimate the amount of impurity phases in the films, to characterize the actual superconducting films, and to test for any preferential orientation within the film. Vibrational modes of the superconductor were found at 148, 226, and 338 cm−1 in both sets of films, at 446 and 491 cm−1 in the Al2O3 films, and at 441 and 500 cm−1 in the MgO films. The measured frequencies of the highest energy modes have been used to determine the oxygen content of the films.

Determination of the Bonding Configurations of Carbon Acceptors in InxGa1−xAs and AlxGa1−xAs

1995 ◽  
Vol 379 ◽  
Author(s):  
R. E. Pritchard ◽  
R.C. Newman ◽  
J. Wagner ◽  
M. Maier ◽  
A. Mazuelas ◽  
...  
Keyword(s):  
Raman Scattering ◽  
Nearest Neighbors ◽  
Ir Absorption ◽  
Vibrational Modes ◽  
High Solubility ◽  
Compositional Range ◽  
Local Environments ◽  
Localized Vibrational Modes

ABSTRACTThe local environments of CAs acceptors in InxGa1−xAs and AlxGa1−xAs have been determined from the localized vibrational modes (LVMs) of both isolated CAs impurities and H-CAs pairs using infrared (IR) absorption and Raman scattering techniques. In as-grown layers of InxGa1−xAs (x<0.1), a single LVM due to isolated CAs acceptors was observed. The introduction of hydrogen led to the formation of H-CAs pairs and a single A1−-mode (stretch) and a single A1+-mode (XH) were observed for the InxGa1−xAs layers. All the LVMs were identified with carbon in CAsGa4 cluster configurations implying that less than 5 % of the detectable carbon atoms were present in clusters incorporating one or more CAs-In bonds. For AlxGa1−xAs, five stretch modes and five X-modes of the H-CAs pairs were observed for 0<x<1 and each mode was assigned to configurations for which the originally unpaired CAs had 0,1,2,3 or 4 Al nearest neighbors. These results show that carbon does not appear to form bonds with In atoms for the InxGa1−xAs samples investigated and this can explain the difficulty found in incorporating CAs acceptors in InxGa1−xAs with x>0.1 for some growth techniques. CAs acceptors can form strong bonds with both Al and Ga atoms, however, leading to a high solubility of carbon in AlxGa1-xAs over the full compositional range.

N-induced vibrational modes in GaAsN and GaInAsN studied by resonant Raman scattering

2001 ◽  
Vol 90 (10) ◽  
pp. 5027-5031 ◽  
Author(s):  
J. Wagner ◽  
T. Geppert ◽  
K. Köhler ◽  
P. Ganser ◽  
N. Herres
Keyword(s):  
Raman Scattering ◽  
Vibrational Modes ◽  
Resonant Raman ◽  
Resonant Raman Scattering

Lattice Relaxation Effects in Si and GaAs Nanocrystals

1994 ◽  
Vol 358 ◽  
Author(s):  
X. S. Zhao ◽  
Y. R. Ge ◽  
J. Schroeder ◽  
P. D. Persans
Keyword(s):  
Gallium Arsenide ◽  
Optical Properties ◽  
Porous Silicon ◽  
Raman Scattering ◽  
Lattice Relaxation ◽  
Experimental Results ◽  
Vibrational Modes ◽  
Strain Effects ◽  
Relaxation Effects ◽  
Almost All

ABSTRACTRaman scattering results on porous silicon, and silicon and gallium arsenide nanocrystals show that almost all vibrational modes become Raman active and remarkably soft in these nanocrystal systems. The experimental results further demonstrate that the carrier-induced strain effects play an important role on the optical properties of such nanocrystal systems.

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