Photoluminescence Spectroscopy of CdTe

Low temperature photoluminescence (PL) spectroscopy was used to evaluate CdTe single crystals grown by a vertical gradient freeze method. Materials suitable for xray detectors preparation were in the center of attention. Both usual above-gap-excitation and rarely used below-gap-excitation was employed to investigate native defects and impurities. Tunable Ti-sapphire laser was applied to study excitation spectra (PLE). Radiative recombinations of free and bound excitons, as well as band-to-defect transitions (like shallow acceptors and A-centers) give rise to emission bands. An effect of hot luminescence was observed in connection with A-center transitions.