Study of surface recombination velocity of Cd1−xZnxTe radiation detectors by direct current photoconductivity

Abstract

The surface recombination velocity of a ${\mathrm{Cd}}_{\text{1−x}}{\mathrm{Zn}}_x\mathrm{Te}$ (CZT) radiation detector treated by mechanical polishing and by a standard 5% bromine in methanol chemical etch is reported. The light power dependence of the surface recombination velocity was measured using dc photoconductivity. The results reveal that the surface recombination velocity is a function of the electron generation rate, which can be described by a Shockley–Read one-center model. It was observed that the surface recombination velocity of the CZT detector treated by polishing only is much larger than that treated with polishing followed by chemical etching. The correlation of dc photoconductivity and low-temperature photoluminescence measurements of the CZT detector is also discussed.