An analysis of defects induced by high dose γ-ray irradiation and their influence on the charge transport properties in CdZnTe detectors

Abstract

Radiation damage effects were important issues for the development of CdZnTe detectors in space-exploration field applications. In this study, we explored the radiation damage mechanisms on CdZnTe crystals based on the Kinchin-Pease model. The type and evolution of irradiation induced defects under different gamma ray doses were investigated by the photoluminescent technique. Laser beam induced transient current measurement was applied to investigate the influence of defects on the charge transport property. Our results demonstrated that the radiation induced defects accumulated negative space charges, which significantly distorted the electric field distribution and reduced electron mobility by enhancing the ionized impurities scattering effect. By correlating the results with 241Am gamma ray radiation response spectra measurement, the effects of radiation damage on the detector performance were discussed.