Optical study of the influence of CdCl2 in large area CdS thin films grown by RF-sputtering

Abstract We present the results obtained by photomodulation (PM) at room temperature of semiconductor CdS thin films grown in large area (450 cm2). The thin films were deposited on conducting glass (SnO2:F 7 Ω/□) by radio frequency-planar magnetron sputtering with a substrate temperature (Ts) of 250 °C, an Argon pressure of 20 mTorr, a radio frequency power of 300 W and with a deposition time (td) of 60 min. A thermal treatment with CdCl2 in these thin films at different annealing times was carried out. In general the PM spectra show a better crystal quality in the CdS thin films annealed with CdCl2, which is corroborated with atomic force microscopy (AFM) and observed in the efficiency of the solar cells processed with these films.