Structure of vacuum, evaporated CdxZn1–xS thin films

Abstract

CdxZn1–xS alloy films are prepared by evaporation from a mixture of CdS and ZnS powder in suitable proportions and their structural properties are investigated as a function of substrate temperature. Both the structure and the lattice parameter of the structures exhibit a strong dependence on temperature of deposition. The variation in lattice parameters of the alloy films as a function of substrate temperature is qualitatively explained on the basis of non-stoichiometry arising due to the presence of excess metal atoms. The presence of excess metal atoms is a consequence of the fact that CdS and ZnS dissociate during evaporation and the constituents have different sticking coefficients on the substrate during condensation depending on the deposition conditions particularly substrate temperature.