The effects of temperature on space charge and internal electric field distribution in CdZnTe detector

The effects of temperature on the distribution of space charge and internal electric field in CdZnTe detectors were theoretically simulated by TCAD software. The mechanisms of space charge distribution in CdZnTe detectors at different temperatures and how to manipulate the internal electric field to achieve good detector performance were discussed in this study. The results demonstrated that an uneven internal electric filed distribution was obtained in low temperature. With increasing temperature, the ionized deep levels tended to capture electrons while unionized deep levels to emit electrons. The sub-bandgap light with a wavelength of 850nm and light intensity of 8x10-8W/cm(2) were utilized to manipulate space charge distribution by enhancing optical excitation of electrons from the valence band into the ionized deep donor levels. Thus, a flatter internal electric field were achieved, which greatly reduces the probability of carriers being trapped or recombined by defect levels during charge transport processes and then significantly improves the charge collection efficiency of detectors in low temperatures. This simulation results provide a theoretical basis for the application of CdZnTe detectors in astronomical field.