Photoluminescence studies of CdTe polycrystalline films

Abstract

Photoluminescence (PL) studies of CdTe polycrystalline films are reported. The films were grown using the modified close space sublimation technique on sapphire substrates. The mean grain size in the investigated films was ranged from 10 up to 360 μm. The distinct spectral bands around 1.580 and 1.440 eV were observed at 77 K. These bands are attributed to shallow bound excitons at dislocations and deep defects, respectively. The intensity of luminescence related to dislocation defects is found to be proportional to the density of grain boundaries. The nature of grain boundaries in the investigated films has been briefly discussed.