Effects of zinc salts on the structural and optical properties of acidic chemical bath deposited ZnS thin films

ZnS thin films were deposited from different zinc salts by chemical bath deposition (CBD). Structural, morphological and optical characterizations were performed using different methods such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectra. The particle sizes of as-deposited ZnS thin films were calculated to be about 12.5-15.5 nm and the crystal qualities were improved after annealed at 500 degrees C in Ar/H2S (5%) atmosphere. Optical absorption measurements indicated that the band gaps of ZnS thin films were in the range of 3.66-3.83 eV and they decreased with the increasing of particle sizes. ZnCl2 was found to the best precursor due to the higher crystal quality and compact surface of deposited ZnS thin films. (c) 2012 Published by Elsevier Ltd.