Carrier transport properties of CdTe detector under polarization condition

Abstract

Cadmium telluride (CdTe) is a promising material for semiconductor-based roomtemperature radiation detectors because of its wide bandgap and relatively good carrier transport properties. One remaining issue of CdTe detectors is an instability arising in longterm operation. This instability, called polarization, is explained by charge accumulation due to carrier trapping/detrapping at deep defect levels. However, previous explanations did not include carrier transport in CdTe. In this study, we have investigated carrier transport properties by measuring the carrier transit time at each stage of polarization. As a result, we have developed a polarization model including carrier transport and calculated the electric field distribution across the CdTe detector during polarization.