VAPOR-PRESSURE SCANNING OF NONSTOICHIOMETRY IN CDTE

Results of vapor pressure scanning of the cadmium telluride solidus surface are reported. The deviation from stoichiometry is found to be up to (0.6-13.8) × 10-1 at.% at temperatures from 945 to 1360 K and vapor pressures from 2.3 to 87.2 kPa on the tellurium side, while that on the cadmium side is (0.1-3.3) × 10-3 at.% in the temperature and vapor pressure ranges from 695 to 992 K and from 0.5 to 57.3 kPa, respectively. The position of the congruent sublimation curve in the P-T-X phase space is discussed and some specifics of the solidus surface are outlined. The maximum congruent sublimation temperature was found to be 1324 K, 41 K lower than the maximum melting point of CdTe. P(Cd)-T and P (Te2-T projections of the Cd-Te phase diagram are presented. Partial molar enthalpies and entropies of the component elements are deduced for cadmium telluride. © 1993 Academic Press, Inc.