Mechanisms of laser-induced defect formation and In doping in CdTe crystals

The results of comprehensive investigations of time-resolved optical reflectivity, atomic force microscopy, reflection of high-energy electron diffraction, current-voltage characteristic, exciton photoluminescence in (111)B oriented CdTe crystals subjected to irradiation with nanosecond KrF excimer laser pulses have been discussed. The influence of laser irradiation on the surface state, crystalline and point defect structure was studied. The peculiarities of pulsed-laser-induced melting and following crystallization of the CdTe surface as dependence of laser energy density have been analyzed. The melting and ablation thresholds were determined as 50 mJ/cm² and 145 mJ/cm², respectively. Using laser irradiation of CdTe crystals pre-coated with an In dopant film, it was possible to suppress self-compensation mechanisms and fabricate the CdTe-based diodes promising for nuclear radiation detectors. The mechanisms of laser-induced defect formation and doping have been discussed.