Phonon modes of ZnS1−xTex alloys epitaxially grown on (100) GaAs substrates

Abstract

ZnS 1−x Te x (0<x<1) alloys grown on (100) GaAs substrates by molecular beam epitaxy are investigated using the x-ray diffraction and Raman scattering. The frequencies of long wavelength ZnTe-like and ZnS-like longitudinal optical phonons determined from Raman scattering show linear variation with the composition x. The frequency of the zone-center optical phonons as a function of x of the ZnS1−xTex mixed crystal shows a typical two-mode behavior, which is in good agreement with the theoretical results from a modified random-element isodisplacement model.