Passivation effect on Cd0.95Mn0.05Te0.98Se0.02 radiation detection performance

CdTe-based detectors have the problem of Te-rich surface layers caused by Br etching, which is one of fabrication steps. Te-rich layer acts as a trapping center and serves as an additional source of charge carriers, thereby degrading transport property of charge carriers and enriching leakage current on surface of detector. To solve this problem, we introduced sodium hypochlorite (NaOCl) as a passivant, and investigated its effect on Cd0.95Mn0.05Te0.98Se0.02 (CMTS), by analyzing chemical state of surface and its performance. After passivation with NaOCl, the results of X-ray photoelectron spectroscopy (XPS) shows the formation of tellurium oxide and elimination of water on CMTS surface, and CMTS presented enhanced performance with Am-241 radioisotope. Consequently, it is demonstrated that the passivation with NaOCl reduces leakage current, compensates defect, and elevates transport of charge carriers, thereby decreasing charge loss of carriers and improving performance of CMTS detector.

Automated summary

CdTe-based detectors suffer from the issue of Te-rich surface layers caused by Br etching. These layers act as trapping centers and additional source of charge carriers, which degrade the transport property of charge carriers and increase the leakage current on the detector's surface. To solve this problem, sodium hypochlorite (NaOCl) was introduced as a passivant, and its effect on Cd0.95Mn0.05Te0.98Se0.02 (CMTS) was investigated. The passivation with NaOCl reduced leakage current, compensated defects, improved transport of charge carriers, decreased charge loss, and enhanced the performance of the CMTS detector.