Study on the behaviors of impurities in cadmium zinc telluride

Impurities in three cadmium zinc telluride (Cd_1-xZn_xTe or CZT) ingots grown by the modified vertical Bridgman (MVB) method were examined by using inductively coupled plasma mass spectrometry (ICP-MS). The distribution and segregation of impurities along the CZT ingots were found to vary with the concentration and the growth conditions. Photoluminescence (PL) and voltage-current measurements were performed to evaluate the effects of the impurities on the optical and electrical properties. The red shift of the (D⁰, X) and DAP positions and the broadening of the DAP band in PL spectrum were observed in the high-impurity CZT ingot. The voltage-current measurement shows a higher resistivity when the impurity concentration was increased. The above results imply that the high-impurity CZT ingot was highly compensated.