Carrier transport performance of Cd0.9Zn0.1Te detector by direct current photoconductive technology

Abstract

In this paper, based on the derivation of the Hecht model and Many model, we establish a new theoretical model and deduce its mathematical equation by considering an even-distributed charged center of certain concentration under constant illumination. This model helps us deeply understand the carrier transport performance of Cd0.9Zn0.1Te (CZT) under various illuminations and non-uniform distribution of the internal electric field in CZT. In our research, direct current photoconductive technology (DCPT) is applied to assess the electrical transport properties of carriers in CZT crystals, which is verified by room temperature Am-241 alpha-particle responses and charge collection efficiency test. The mobility-lifetime product (μτ) for carriers is extracted from fitting the Hecht model by DCPT for CZT radiated from the cathode and anode by a constant laser, respectively. Moreover, the carrier transport properties of CZT under various light intensities and during a wide range of temperatures are also taken and analyzed in detail, which enable us to develop the best performance of CZT. In addition, we figure out a method for estimating μeτe and μhτh on different positions of CZT wafer on the basis of the pixel detector that collects single polarity charge, and several corrective actions have improved the accuracy of the measurement.