EXPERIMENTAL STUDIES ON MASS-TRANSPORT OF CADMIUM-ZINC TELLURIDE BY PHYSICAL VAPOR TRANSPORT

Experimental studies on mass transport of ternary compound, Cd1-xZnxTe by physical vapor transport (PVT) for source compositions up to X=0.2 1 are presented. The effect of thermochemical (temperatures, vapor com position) and other factors (preparation of the source, crystal growth rate, temperature gradient) on composition and composition profiles o f the grown crystals were investigated. A steep decrease in the mass f lux with an increase in X(crystal) for X < 0.1, and a difference in co mposition between the source and the deposited material have been obse rved. The composition profiles of the crystals were found to depend on the density and pretreatment of the source, and on the temperature gr adient in the source zone. The homogeneity of the crystals improves at low undercoolings and/or when an appropriate excess of metal constitu ents is present in the vapor phase. The experimental results are in go od agreement with our thermochemical model of this system.