Anomalous Te Inclusion Size and Distribution in CdZnTeSe

The effect of selenium in CdZnTe was investigated by characterizing the Cd_0.9Zn_0.1Te_0.98Se_0.02 crystal. The bandgap of Cd_0.9Zn_0.1Te_0.98Se_0.02 is smaller than Cd_0.9Zn_0.1Te. In addition, its value in ingot follows the zinc-segregation tendency than that of selenium. There was a recognizable difference in the amounts of compensating dopants, the distribution of Te inclusions, and the performance of the detector. The amounts of indium doping for the compensation were reduced by the addition of selenium, which provided the highest partial pressure in the melts. Thus, the generation of Cd vacancies, which is a native defect in CdZnTe, was prevented. In addition, the size of Te inclusions varied from the tip, middle, and heel of the CdZnTeSe ingot. The addition of selenium may change the thermal conductivity of CdZnTeSe melts, which is responsible for reducing the bulging of the retrograde solidus line near stoichiometry. The planar CdZnTeSe detector showed a 59.5-keV gamma peak for Am-241 with an 11% of energy resolution.