Characterization of deep defects in Cd_xHg_1-xTe by injection-level spectroscopy of carrier lifetime

Characterization of deep defects in cadmium mercury telluride (CMT) Cd_xHg_1-xTe is of great importance for controlling the properties of infrared detectors made of this material. This paper presents a theoretical and experimental investigation of deep defects in CMT by injection-level lifetime spectroscopy of charge carriers. Concentration, energy level of the defect, and capture cross-section for electrons and holes have been determined. It was found that carrier lifetime in CMT films before laser processing deviates from that found theoretically, which was attributed to the effect of grain boundaries. Agreement of theory with experimentally measured lifetime was achieved in the films after laser processing. It is shown that the photoconductivity value at low illumination intensities is defined by majority carriers. Accordingly, lifetime, determined by photoconductance decay, corresponds to majority carriers.