CdZnTeSe: An emerging room-temperature semiconductor detector material (Conference Presentation)

Enormous effort has been exerted on research and development of CdZnTe (CZT) over the past two decades, as well as the pursuit of an alternative material to mitigate the disadvantages in today’s CZT material or provide comparable device performance at a lower cost of production. Although the quality of CdZnTe crystals has been improved drastically over the past few years and the material cost has steadily decreased, the yield of large-volume high-quality detector-grade CZT continues to be an issue due to its poor thermo-physical properties. TlBr was found to be a promising material to compete with CZT, but the contact degradation and device stability are still big issues and severely hinder the deployment of commercial TlBr-based devices for nonproliferation and national security applications. At BNL, we are developing a new compound Cd1-xZnx Te1-y Sey (CZTS) that holds promise as a potentially viable crystal for the replacement of CZT for some radiation detection and imaging applications. The addition of Se in the CZT compound has been found to be very effective in a drastic reduction of the sub-grain boundary network, leading to better compositional and charge-transport homogeneity. The new material has tremendous potential to increase the yield of high-quality detectors at a much lower cost of production. The reduction of the sub-grain boundary network can result in detectors with a lower voltage operation and increased detector thickness. Our efforts to develop CZTS for X- and gamma-ray radiation detector applications will be discussed in detail.