Characterization of high Zn content Cd_0.87Zn_0.13Te_0.98Se_0.02 grown using Bridgman technique

CdZnTe (CZT) is a promising commercial material used as a room-temperature operating semiconductor detector for gamma-ray detection. Recently, CdZnTeSe (CZTS) detectors improved upon the properties of CZT by improving homogeneity and reducing defect properties, thereby enabling higher production yield of high-quality crystals. However, addition of selenium to CZT will reduce the bandgap and increase the amount of thermally stimulated electrons, resulting in low resistivity of the crystal. In this study, the enhancement of zinc content was introduced to compensate the bandgap reduction owing to selenium addition, while maintaining the improved properties of selenium addition. The morphology and stoichiometry of CZTS were determined using scanning electron microscopy and electron probe micro-analyzer. Furthermore, the calculated bandgap with stoichiometry was compared with the measured bandgap using UV-Vis measurement and Tauc plot. The electrical, chemical, and other spectroscopic properties were characterized using an I-V curve, X-ray photoelectron spectroscopy, and gamma-spectroscopic techniques, respectively. Moreover, it was proven that the high zinc CZTS can exhibit superior properties owing to selenium addition without affecting the bandgap reduction.