Thick film compound semiconductors for X-ray imaging applications

The current status of thick film compound semiconductor materials for radiation imaging applications is reviewed. Polycrystalline high-Z semiconductors offer a number of significant advantages for X-ray and γ-ray imaging, and provide an excellent technology for large area direct conversion imaging detectors. There has been significant recent progress in the development of high-purity polycrystalline layers in two distinct material groups, namely the CdTe/CdZnTe material system, and the Z>80 compounds of Hg, Pb, Bi and Tl. In this paper the charge transport and detection performance of these various thick film materials is summarised, and the most recent imaging performance of prototype detector systems is presented.