Irradiation-induced defects in CdTe and CdZnTe detectors

The performance of room-temperature CdTe and CdZnTe detectors exposed to a radiation source can be strongly altered by the interaction of the ionizing particles and the material. Up to now few experimental data are available on the response of II-VI compound detectors to different types of radiation sources. We have focussed our attention on the effects of gamma -rays and neutron irradiation and we have investigated the exposed detectors by means of dark current measurements and of quantitative spectroscopic analyses at low and medium energies. The deep traps present in the material have been characterized by means of photo-induced current transient spectroscopy anal yses, which allow for the determination of the trap apparent activation ene rgy and capture cross-section The evolution of the trap parameters with inc reasing irradiation doses has been monitored for both types of radiation so urces. The comparison of the results obtained for CdTe and CdZnTe detectors allows us to deepen our understanding of the detectors' properties and per formance. (C) 2001 Elsevier Science B.V. All rights reserved.