PHOTOLUMINESCENCE STUDIES OF SEMICONDUCTING POLYCRYSTALLINE CDTE-FILMS

We report the first systematic measurements of the temperature depende nce of the photoluminescence (PL) in the range of 10-300 K in CdTe. Th e experiments were carried out on semiconducting CdTe films of high qu ality grown by a modified close-spaced vapour transport (CSVT) techniq ue. Several luminescence bands were observed, one around 1.4 eV showin g a temperature-independent behaviour, and another band located around 1.52 eV, at 300 K, showing a strong temperature dependence. The excit onic origin of this band at low temperatures has been confirmed by the dependence of the PL intensity on the excitation intensity. A band-to -band luminescent recombination component at high temperatures is also observed. This study allows us to elucidate the nature and basic phys ical properties of the bound exciton as well as the temperature depend ence of the band gap.