Study on ZnS thin films prepared by chemical bath deposition

We reported the deposition and structural characterization of zinc sulfide (ZnS) thin films by chemical bath deposition (CBD) from a bath containing thiourea, ZnSO4 and ammonia in aqueous solution on common glass substrates. The solution concentration and annealing condition played a very important role on transmissivity, homogeneity, crystal and transmissivity of ZnS thin films. Spectrophotometer, X-ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive spectroscopy (EDS), digital four-point probe resistance measurement were used to characterize their properties and composition. As a result, transmissivity for the samples were more than 80%. Then it would be stable above 600 nm. The surface morphology of the thin films were homogeneous. However, there were some white spots in the SEM patterns that might be colloidal particles sedimentation mixed with ZnS. These particles could be amorphous or no crystal. According to the detection, ZnS films' resistance were changed with the ZnSO4 solutions' concentration.