Effects of p/n inhomogeneity on CdZnTe radiation detectors

Spectrometer grade, room-temperature radiation detectors have been produced on Cd0.90Zn0.10Te grown by the low-pressure Bridgman technique. Small amount of indium has been used to compensate the uncompensated Cd vacancies for the crystals to be semi-insulating. The properties of the detectors are critically dependent on the amount of excess Te introduced into the growth melts of the Cd0.90Zn0.10Te crystals and the best detectors are fabricated from crystals grown with 1.5% excess Te. Detector resolution 57Co and 241Am radiation peaks are observed on all detectors expect the ones produced on Cd0.90Zn0.10Te grown from the melt in the stoichiometric condition. The lack of resolution of these stoichiometric grown detectors is explained by a p/n conduction-type inhomogeneity model.