PHASE RELATIONS IN THE Sb2Te2S-Bi2Te2S SYSTEM AND CHARACTERIZATION OF Sb2-xBixTe2S SOLID SOLUTIONS

Abstract

The phase equilibria of the Sb2Te2S-Bi2Te2S system was studied by powder X-ray diffraction (PXRD), differential thermal analysis (DTA), scanning electron microscope (SEM) and energy dispersive Xray (EDX) microanalysis. It was shown that due to incongruent melting of the Sb2Te2S compound the system is non-quasibinary, but it is stable below the solidus and characterized by the formation of a continuous series of solid solutions with a tetradymite-like hexagonal structure. The lattice parameters were determined from powder diffraction patterns. It was established that the crystal lattice parameters of solid solutions vary linearly with composition