High voltage optimization in CdZnTe detectors

The focus of this paper is to investigate, experimentally and theoretical, the optimum operating bias, in cadmium zinc telluride Cd 0.9Zn0.1Te (CZT) crystals grown using the traveling heater method (THM), required to achieve maximum energy resolution. It was found that 5 mm thick detectors that have low electron trapping, (μτ)e≥1×10−2 cm2/V, operates efficiently at relatively low applied bias, 200 V; while detectors with high electron trapping, (μτ)e≤5×10−3 cm2/V, required relative high voltage: as high as 1000 V for 5 mm thick detectors. Similarly 10 mm thick detectors can be operated at as low as 500 V. Moreover, both charge collection efficiency (CCE) and energy resolution(ER) were found to follow the same trend.