Compensation origins in II-VICZT materials

It is well known that II-VI CdTe, and CdZnTe (CZT) materials suffer from th e presence of cadmium vacancies (V-Cd) and their complexes with impurities and defects, which lead to low resistivity and trapping. These defects are known generally as the A-centers, around 0.1-0.2 eV. In order to increase t he resistivity, intentional and non intentional chemical and physical compe nsations are conducted; for CdTe, halogens (Cl, Pr, I) or In are generally used, while for CZT, the compensation origins are still unknown. In this pa per, we try to study the compensation by measuring deep levels and very sha llow levels at temperatures as low as helium temperature by photoluminescen ce (PL) and photoinduced current transient spectroscopy (PICTS), and model the resistivity in order to clarify the origins of the compensation and the high resistivity in CZT materials. (C) 2000 Published by Elsevier Science S.A. All rights reserved.