Synthesis and characterization of aluminum dope zinc sulfide (Al:ZnS) thin films by chemical bath deposition techniques

Abstract

A well adherent thin films of Aluminum doped zinc sulphide (Al:ZnS) has been deposited on silica glass substrates using acidic chemical bath deposition (CBD) containing zinc acetate, Aluminum Chloride, and thioacetamide. EDTA was used as complexing agent to control the free ion concentration of the thin films. Aluminum concentrations were doped by 2%, 4%, and 6% while keeping other deposition parameters constant as deposited Al:ZnS thin films. The samples were characterized by BrukerD8 diffractometer with cuKα (λ=1.5406A˚) radiation working at 40 mA and 40 kV, JOEL-2300 Analysis Station Scanning electron microscope (SEM), and Perkin Elmer Lambda 950 UV-vis/NIR spectrophotometer. The structural characterization of the samples show that no intense peaks were observed indicating the amorphous nature of the films. The surface morphology studies of as deposited Al:ZnS thin films shown the films were uniform, dense, and composed of spherical shaped grains. EDAX shows the elemental composition of Zn, S, and Al. The ratios of Zn/S in Stoichiometric even though the concentration of Aluminum is increased. Optical absorbance of the films decreased with increase Aluminum concentration. The large band gap makes them good materials for application as a window layer for solar cells.