Studies of Cd-vacancies, indium dopant and impurities in CdZnTe crystals (Zn = 10%)

Abstract

Using modified vertical Bridgman and a seeded technique, 3-inch-diameter CdZnTe (CZT) ingots were successfully grown with 40% of the ingots having single-crystal volumes of over 300 cm/sup 3/, and 80% of the ingots with single-crystal volumes of over 100 cm/sup 3/. High-yield growth of CZT crystals with these dimensions enables the production of novel monolithic, multi-element detectors. Defects such as Cd-vacancies, indium dopant and impurities were studied systematically. The studies show that by appropriately reducing the Cd-vacancy and the Group III dopant, one can increase the /spl mu//spl tau/(e) and /spl mu//spl tau/(h) products. Furthermore, the indium doping and the purity of the CZT were found to limit the value of the /spl mu//spl tau/(e) product. The "best" purity source material coupled with an optimized indium doping concentration will produce /spl mu//spl tau/(e) products as high as 1.8x10/sup -2/ cm/sup 2//V (collimated and the "best" area), and the best /spl mu//spl tau/(h) is 7x10/sup -4/ cm/sup 2//V.