CHARACTERIZATION OF DEFECT LEVELS IN CHEMICALLY DEPOSITED CDS FILMS IN THE CUBIC-TO-HEXAGONAL PHASE-TRANSITION

Spectral photoconductivity, photoconductive quenching, photoluminescen ce, and thermally stimulated current measurements, have been carried o ut in order to study the evolution of defect energy levels in CdS thin films, grown in cubic phase by chemical bath deposition, as a functio n of thermal annealing temperatures in Ar+S-2 atmosphere. The results are influenced by a cubic-to-hexagonal phase transition. From those me asurements, a number of trap levels and deep levels in the forbidden b and are determined. The results can be explained in terms of the evolu tion of native and phase transition generated defects in the sample st ructure. (C) 1997 American Vacuum Society.