Optical properties of electrodeposited CdTe thin films

The absorption coefficient spectra of the electrodeposited CdTe thin films were analyzed and compared with that of the single crystal. Pinhole-free th in films facilitated the analysis of the high-energy regions of the absorpt ion coefficient spectra. The various allowed direct and indirect transition s were detected successively by subtracting the extrapolated values of the lower-energy transitions. The effect of heat treatment on the optical trans itions were analyzed with films annealed at 300 degrees C in air, argon and CdCl2. The direct band gap of the electrodeposited films decreased with in creasing film thickness and approaches the value of the single crystal. The films annealed at different environments show slightly lower value for the band gap. Annealing in argon caused significant change in the optical tran sition spectra. (C) 1999 Elsevier Science B.V. All rights reserved.