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Characterization of MBE‐grown Ga 1− x Al x As alloy films by Raman scattering
Author(s) -
Hou Y. T.,
Feng Z. C.,
Li M. F.,
Chua S. J.
Publication year - 1999
Publication title -
surface and interface analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.52
H-Index - 90
eISSN - 1096-9918
pISSN - 0142-2421
DOI - 10.1002/(sici)1096-9918(199908)28:1<163::aid-sia598>3.0.co;2-i
Subject(s) - molecular beam epitaxy , raman scattering , alloy , raman spectroscopy , ternary operation , phonon , scattering , condensed matter physics , asymmetry , materials science , spectral line , ternary alloy , chemistry , epitaxy , analytical chemistry (journal) , optics , nanotechnology , metallurgy , physics , quantum mechanics , astronomy , layer (electronics) , chromatography , computer science , programming language
Molecular beam epitaxy (MBE)‐grown ternary Ga 1− x Al x As films, with Al composition x ranging from 0 to 1 in steps of 0.1, have been studied by Raman scattering at room temperature and at 80 K. The observed broadening and asymmetry of the first‐order longitudinal‐optical phonon spectra induced by alloy disorder are simulated using the spatial correlation model. The obtained correlation length for GaAs‐like and AlAs‐like modes are observed to decrease as the reduction of Ga composition 1− x and Al composition x , respectively. It is also shown that the correlation length depends sensitively on the composition. No significant temperature or phonon mode dependence is found. A combination with thermodynamic analysis suggests that the random compositional distribution in alloy seems to be the dominant contribution to this disorder effect. Copyright © 1999 John Wiley & Sons, Ltd.