P-T-x Phase Diagram of the Lead Telluride System

Abstract

Small single crystals of lead telluride were annealed at various tellurium or lead pressures in order to control their stoichiometric compositions. Samples equilibrated under high tellurium pressures were p-type and those under low tellurium or high lead pressures n-type. The tellurium pressures corresponding to the p-n transition boundary were found to be about 3×10^-5 mmHg at 600°C and about 10^-3 mmHg at 750°C. From the analysis of the experimental results, high temperature equilibria for lead and tellurium vacancies were calculated by using the method of Kröger and Vink for imperfections in lead sulfide. Melting points of lead telluride were determined under various tellurium pressures by the thermal analysis of the freezing process and its P-T-x phase diagram was constructed.