Size dependent optical characteristics of chemically deposited nanostructured ZnS thin films

ZnS thin films of different thicknesses were prepared by chemical bath deposition using thiourea and zinc acetate as S2− and Zn2+ source. The effect of film thickness on the optical and structural properties was studied. The optical absorption studies in the wavelength range 250–750 nm show that band gap energy of ZnS increases from 3·68–4·10 eV as thickness varied from 332–76 nm. The structural estimation shows variation in grain size from 6·9–17·8 nm with thickness. The thermoemf measurement indicates that films prepared by this method are of n-type.