Raman scattering and optical-absorption studies of the metastable alloy system GaAsxSb1-x

T. C. McGlinn*, T. N. Krabach, M. V. Klein, G. Bajor, J. E. Greene, B. Kramer, S. A. Barnett, A. Lastras, S. Gorbatkin

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

58 Scopus citations

Abstract

The optical properties of GaAsxSb1-x alloys grown across the entire concentration range by multitarget sputter deposition are reported. X-ray diffraction, optical absorption, and Raman spectra show the samples to be single-crystal, single-phase alloys for all x, including those in the miscibility gap. Alloy lattice constants are found to vary linearly with concentration. The direct-point energy gaps, determined from optical-absorption measurements, show significant negative bowing. Contrary to previous reports, the Raman spectra exhibit two-mode behavior throughout, including a local mode of As in GaSb and a resonant mode of Sb in GaAs. An analysis of peak frequencies and line shapes versus concentration is given in the context of disorder effects. We observe broadenings much less severe and asymmetric than those seen in similar systems and usually interpreted in terms of k 0 density-of-states activation. The observed adherence to zone-center selection rules for all x, suggests a more accurate interpretation to be one involving the k0 spectral projection of the density of states.

Original languageEnglish (US)
Pages (from-to)8396-8401
Number of pages6
JournalPhysical Review B
Volume33
Issue number12
DOIs
StatePublished - 1986

ASJC Scopus subject areas

  • Condensed Matter Physics

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