Vapor Phase Transport and Stoichiometry Control of Cadmium Sulfide

Abstract

Cadmium sulfide single crystals were grown by the sublimation method under controlled partial pressures of the constituent elements. By investigating the transport mechanism in connection with the controlled partial pressures, it was found that controlled partial pressures higher than that corresponding to the minimum total pressure in the closed tube (Pmin) were required in order to control deviation from stoichiometry during the growth process. The electrical conductivity of the grown crystals changed by twelve orders of magnitude depending on the controlled partial pressures. This behavior is explained by the increase or decrease of native defects and the effect of the partial pressure was recognized only when the controlled partial pressure was higher than that corresponding to Pmin. Some information on traps was also obtained.