Bandgap engineering of Cd1-xZnxTe1-ySey(0 < x < 0.27, 0 < y < 0.026)

Abstract

CdZnTe (CZT) detectors with more than 10% zinc content did not show any remarkable improvement in the detector performance due to the additional defects introduced by the higher zinc content. However, recent research showed that the formation of defects was suppressed effectively by adding a small amount of selenium (at. 2%) in CZT. On this basis, we attempted to enhance the detector performance through the bandgap engineering by increasing the zinc content up to 25%, while adding 2% of selenium. Multiple CdZnTeSe (CZTS) ingots with Zn = 10, 12.5, 15, and 20%, while keeping the Se contents at 2%, were grown by the Bridgman method. The bandgap of CZTS for the different Zn and Se contents was analyzed and then introduced modified equation for predicting more accurately the bandgap of other alloy compositions. Also, the crystallinity of CZTS was evaluated by photoluminescence measurements. The pulse height spectra for Am-241 and Co-57 sources were used to evaluate the detector performance for the CZTS samples.