Studies on ternary PbZnS films suited for optoelectronic applications

This paper reports the deposition and characterisation of spray-deposited ternary PbZnS thin films. PbZnS thin films were prepared with different concentrations of zinc (0, 1, 2, 3 and 4 wt-%). XRD studies reveal the polycrystalline nature of the films. The doped films exhibit face-centred cubic structure with a strong (2 0 0) preferential orientation similar to that of the undoped film. Lead sulphide (PbS) unit cell volume contracts with Zn doping. Transparency increases with Zn doping and optical band gap values of the PbZnS films coated with Zn concentration greater than 1 wt-% exhibit a blue shift which may be attributed to Moss-Burstein effect. Electrical studies reveal that all the films have resistivity in the order of 10(-1) ohm-cm. The obtained results infer that Zn doping enhances the optical and electrical properties of pure PbS making the doped films suitable for optoelectronic applications.