Recent progress in n-type CdZnTe arrays for gamma-ray spectroscopy

This study focuses on the characterization of n-type CdZnTe gamma-ray spect rometers, which are designed for pixelated imaging array. The intentionally doped n-type CdZnTe crystals are grown by IMARAD Imaging Systems by a modi fied horizontal Bridgman technique. Imaging arrays. which are produced by I MARAD with ohmic contacts are compared with arrays with different types of contacts, fabricated at Technion-Israel Institute of Technology. We investi gate the performance of n-type MSM spectrometers fabricated with several ty pes of contacts: ohmic anodes and cathode, rectifying anodes and cathode as well as mixed (i.e., ohmic anodes and rectifying cathode). The DC characte ristics are correlated with the detector dark noise and the spectral perfor mance. The study presents the significant recent advance in the technology of room-temperature semiconductor gamma-ray spectrometers. It also gives ph ysical insight to the parameters that determine the performance of n-type C dZnTe spectrometers. The comparison between spectrometers with different co ntacts may indicate whether the high performance of IMARAD arrays depends u pon electron injection from the cathode, as previously suggested, or to ade quate hole mobility-lifetime products in the n-type CdZnTe material, as sug gested here. (C) 2001 Elsevier Science B.V. All rights reserved.