Investigations on the physical properties of the polycrystalline ZnS thin films deposited by the chemical bath deposition method

Transparent and polycrystalline zinc sulfide (ZnS) thin films were prepared by the chemical bath deposition (CBD) technique onto glass substrates deposited at 80 degrees C using aqueous solution of zinc acetate, thiourea, triethanolamine and tri-sodium citrate at a pH of about 10.55. Triethanolamine and tri-sodium citrate were used as complexing agents. The thickness of the films, which were calculated from the interference patterns around 400-800 nm maxima and minima wavelengths, varied from 403 to 934 nm in the visible range. UV-visible spectrophotometric measurement showed transperancy from 66% to 87% of the films with a direct allowed energy band gap in the range of 3.79-3.93 eV. X-ray diffraction (XRD) patterns prove crystallinity of deposited films that crystallize in the hexagonal phase of ZnS. The ZnS thin films were characterized by XRD, energy dispersive X-ray analysis (EDX) and optical absorption spectra. The current-voltage characteristic of polycrystalline ZnS films grown by CBD are reported. (c) 2006 Elsevier B.V. All rights reserved.