Composition and properties of ZnS thin films prepared by chemical bath deposition from acidic and basic solutions

Abstract

Zinc sulfide thin films were prepared by chemical bath deposition (CBD) on soda lime glass, silicon and gallium phosphide substrates using an acidic (acetic acid-thioacetamide), and ammonia (thiourea or thioacetamide) baths. The thickness of the films varied from a few nm to 100 nm. Films deposited using the acidic bath showed a smaller concentration of Zn-O bonds and are much closer to ZnS stoichiometry, as it was found by X-ray photoelectron spectroscopy and wavelength-dispersive X-ray fluorescence spectroscopies. X-ray diffraction patterns prove crystallinity of as deposited films from the acidic bath, which crystallize in the cubic modification. The optical band-gap energy was determined to be 3.64 eV from the best-fit of spectroscopic ellipsometry measurements. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)