Structural and Optical Properties of ZnS and Cr-ZnS Thin Films Prepared by Chemical Bath Deposition Method

Thin films of ZnS and Cr doped ZnS have been deposited on glass substrates by chemical bath deposition (CBD) method taking ammonia as complexing agent. The pH of the solution was maintained at 8−9 at a temperature of 70 oC. Characterization of the ZnS and Cr-doped ZnS films were carried out using X-ray diffraction (XRD), X-ray Fluorescence Spectrograph (XRFS) and Atomic force microscopy (AFM). Structural properties and optical absorption has been observed for both doped and undoped films. Parameters like crystallite size, lattice constant, microstrain, dislocation density; and optical constants such as extinction coefficient, absorption coefficient for both types of films were measured from XRD and absorbance spectra respectively. Studies show that there is an increase of crystallite size and good optical properties in visible region from 420 nm in Cr-doped ZnS thin film.