Raman and infrared spectroscopy of In1−xGaxSb films grown on GaAs by metal-organic magnetron sputtering

Abstract

Thin films of the novel III–V ternary In1−xGaxSb were grown by metal-organic magnetron sputtering on (001) GaAs substrates. We used Raman scattering and infrared-reflectivity measurements to examine films of thickness 1–2 micrometres with x(Ga) = 0.0, 0.035, 0.07, 0.24, 0.32, 0.68, and 1. We observe two-mode phonon behavior over the range 0 < x < 0.7, and derive the dependence of the GaSb and InSb-like transverse and longitudinal optical phonon frequencies and intensities on Ga composition. The Raman line widths at half maximum are < 10 cm−1 and the polarization behavior of the Raman spectra obeys the selection rules for a (001) surface, indicating that the films are of good crystalline quality.