CATHODOLUMINESCENCE AND PHOTOINDUCED CURRENT SPECTROSCOPY STUDIES OF DEFECTS IN CD0.8ZN0.2TE

Deep levels in Cd1-xZnxTe have not yet been fully characterized and un derstood, even though this material is very promising for medical and optoelectronic applications. We have investigated p-type semi-insulati ng Cd0.8Zn0.2Te with cathodoluminescence (CL) and photoinduced current transient spectroscopy (PICTS) methods. PICTS analyses allow detectio n of deep levels which are not revealed by other current spectroscopy techniques generally used, as they permit scanning of a wider region o f the energy gap. Five levels have been detected (0.16, 0.25, 0.57, 0. 78, and 1.1 eV) and, by combining the results obtained with the above- mentioned CL techniques, we were able to advance hypotheses on the cha racter (donor or acceptor) and origin of some of these levels. The key role prayed by the 0.78-eV level in controlling the carrier transport properties has also been confirmed.