The effects of Zn incorporation on electrical, photoluminescence and spectral sensitivity of SILAR deposited CdS thin films

The SILAR deposited CdS films were incorporated with various concentrations of zinc using zinc acetate and zinc chloride precursors. The presence of zinc was found to alter the crystal structure and energy bandgap of the films. The bandgap increased by nearly 44% with the increase of zinc concentration in the films. The photoluminescence spectra of the films revealed the presence of several localized defects levels within the forbidden bandgap. The peak spectral response wavelength was found to vary from 500 nm to 400 nm with the increase of zinc. The photocurrent was found to increase with the Cd:Zn ratio. The films with relatively high concentrations of zinc were found to be better suited for the photodetector applications due to their higher photocurrent to dark current ratio.