Optical Phonons of ZnS1–xSex and CdS1–xSex Mixed Crystals: Pressure Effects

Abstract
The ir transmission of the optical phonons for the mixed crystals ZnS1– xSe x and CdS1– xSe x, at various concentrations of x, was studied as a function of pressure up to about 43 kbar. At all concentrations a two-mode behavior was observed. For both systems the high frequency mode exhibits a greater pressure dependence than the low frequency mode. The gap mode observed for the ZnS1– xSe x mixed crystals at low concentrations of Se is found to be pressure insensitive as contrasted to the Cd1- xSe x mixed crystals.