Electrically active point defects in cadmium telluride

Abstract

Hall coefficient and conductivity measurements were made on single crystals of CdTe at temperatures up to 950°C while controlling the partial pressure of either cadmium or tellurium. Measurements made with a cadmium reservoir showed the material to ben-type due to the presence of a doubly ionized native donor, in agreement with the results of Whelan and Shaw. The apparent enthalpy of formation of the donor and its concentration along the cadmium-rich solidus were obtained. Measurements made with a tellurium reservoir close to tellurium saturation are in disagreement with the usual model, which attributes formation ofp-type material under these conditions to the presence, of a native acceptor defect. The results are consistent with a hole concentration originating from an excess of acceptor impurities rather than from a native acceptor.