Study on the temperature dependent properties of detector-grade CdZnTe crystals

To evaluate the charge transport behaviors associated with the temperature variation, the pulse height spectra of CdZnTe crystals were obtained under various bias voltages, in the temperature range of 230-300K, using an un-collimated ²⁴¹Am α particles source with the energy of 5.48MeV. It was demonstrated that the photo-peak positions were non-sensitive to the temperature for high quality CdZnTe crystals. In terms of CdZnTe crystal with de-trapping level defects, the charge drift velocity was significantly delayed due to the re-emission of charge carriers out of the traps. The pulse shapes shown distinct exponential decay component which enhanced as decreasing the temperature. ²⁴¹Am@59.5keV γ-ray spectroscopy response of CZT detector were compared at room temperature and 280K. In addition, the leakage current of the detector, under the electrical field strength of 1500V/cm, were evaluated as a function of the temperature.