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Raman spectra of GaAs-AlxGa1-xAs superlattices

✍ Scribed by Yia-Chung Chang; Shang-Fen Ren; Guozhong Wen

Publisher: Elsevier Science
Year: 1993
Tongue: English
Weight: 118 KB
Volume: 13
Category: Article
ISSN: 0749-6036
DOI: 10.1006/spmi.1993.1030

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✦ Synopsis

Systematic theoretical studies of Raman spectra of (\mathrm{GaAs}-\mathrm{Al}{x} \mathrm{Ga}{1-x} \mathrm{As}) superlattices are presented. The electronic states are described by an envelope-function method and the phonon modes are described in a microscopic rigid-ion model. Both resonant and nonresonant Raman scattering processes are considered. For resonant Raman scattering, the effects of discrete exciton states plus the continuum and the valence-band mixing are included via a (\mathbf{k})-space sampling method. Both the Fröhlich and deformation-potential mechanisms for electron-phonon coupling are considered. These two mechanisms are responsible for principal features in the (z(x, x) \bar{z}) and (z(x, y) \bar{z}) geometries, respectively. We find that the effects of exciton continuum states are quite important and the resonant Raman spectra so obtained are in much better agreement with experiment compared to those without including the exciton continuum states.

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