Quaternary Semiconductor Cd1-xZnxTe1-ySey for High-Resolution, Room-Temperature Gamma-Ray Detection

The application of Cd0.9Zn0.1Te (CZT) single crystals, the primary choice for high-resolution, room-temperature compact gamma-ray detectors in the field of medical imaging and homeland security for the past three decades, is limited by the high cost of production and maintenance due to low detector grade crystal growth yield. The recent advent of its quaternary successor, Cd0.9Zn0.1Te1-ySey (CZTS), has exhibited remarkable crystal growth yield above 90% compared to that of similar to 33% for CZT. The inclusion of Se in appropriate stoichiometry in the CZT matrix is responsible for reducing the concentration of sub-grain boundary (SGB) networks which greatly enhances the compositional homogeneity and growth yield. SGB networks also host defect centers responsible for charge trapping, hence their reduced concentration ensures minimized charge trapping. Indeed, CZTS single crystals have shown remarkable improvement in electron charge transport properties and energy resolution over CZT detectors. However, our studies have found that the overall charge transport in CZTS is still limited by the hole trapping. In this article, we systematically review the advances in the CZTS growth techniques, its performance as room-temperature radiation detector, and the role of defects and their passivation studies needed to improve the performance of CZTS detectors further.

Automated summary

The application of CZT single crystals as high-resolution, room-temperature gamma-ray detectors in medical imaging and homeland security has been limited by low crystal growth yield. The introduction of CZTS has shown significant improvement in crystal growth yield, electron charge transport properties, and energy resolution over CZT detectors, but hole trapping still poses a limitation in charge transport efficiency. Further studies on defects and their passivation are needed to enhance the performance of CZTS detectors.