Analysis of Polarization Phenomenon and Deep Acceptor in CdTe Radiation Detector

High energy-resolution CdTe radiation detectors with Schottky contact show instability with operating time under bias voltage, which is termed as polarization phenomenon. Time stability is one of the important factors for its practical applications. It is considered that this phenomenon is responsible for the deep acceptor level in CdTe bulk. However, the energy position and concentration of the deep acceptor level have been not estimated accurately. We have studied the polarization phenomenon and the parameters of deep acceptor in a Schottky-type CdTe radiation detector. In this paper, we propose a new method which can quantitatively evaluate the parameters of the deep acceptor such as concentration and energy level by measuring the temperature dependence of the current-voltage characteristics of the CdTe radiation detector.