Influence of Cd-rich Annealing on Position-dependent Conductivity Transition in Cd_1-xZn_xTe Crystal

In this study, Cd_1-xZn_xTe(x=0.04) crystals were grown using the Te-rich Vertical Bridgman(VB) method. A position-dependent conductivity transition was found in some of the as-grown Cd_1-xZn_xTe ingots, which caused significant nonuniformity in the Hg_1-yCd_yTe(MCT) focal plane array(FPA) response map. Cd-rich annealing experiments were performed on Cd_1-xZn_xTe ingots with position-dependent conductivity transition, and the relationships between the position-dependent conductivity transition and annealing conditions, including annealing time, temperature, and Cd partial pressure, were studied. Furthermore, by understanding the formation mechanism of Cd vacancies and Cd interstitials, we found that Cd vacancies can be reduced during Cd_1-xZn_xTe ingot growth.