Effect of Thermal Treatment on Electrical Properties of CZT Detectors

In order to understand the contributing factors responsible for the diminished electrical properties during annealing, CZT samples were annealed in the temperature range of 100 - 400$^{\mathrm{o}}$C. Following each thermal treatment measurements of infrared microscopy, current-voltage characteristics, and X-ray photoelectron spectroscopy were performed in order to determine changes in bulk defect morphology, electrical properties, and surface material degradation, respectively. Samples annealed at 300$^{\mathrm{o}}$C demonstrated improvements in the electrical properties of the detector while thermal treatments at 400$^{\mathrm{o}}$C were shown to approximate a critical temperature of deterioration. Reduction in leakage current was observed at elevated temperatures up to 300$^{\mathrm{o}}$, after which increased leakage current was observed at higher temperatures, consistent with previous studies. Attempts were made to explain this critical temperature.