Induced defects and structural changes resulting from the processing of CdTe and CdS thin film

The Rutherford backscattering (RBS) and thermoluminescence (TL) techniques are used to characterize thin films of CdTe and/or CdS deposited onto glass substrates for possible evolution of high-efficiency solar cells. The induced changes following annealing at 400°C for 30 min and chemical processing in saturated CdCl2 solution, are investigated. Major structural changes are noted by the RBS technique in a manner that is a function of the processing conditions. The TL data as obtained from the detected glow curves indicate an impurity influence on both the deep and shallow charge traps and recombination centers. The TL glow curves also reveal the development of shallow defect states accompanied by a decrease in the amount of undesirable tunneling and interface recombination. The complementary TL and RBS results are then discussed based on the model of lowering the interface defects density and the formation of an intermixed interface layer resulting from various impurity and film species interdiffusion