Structural and Optical Properties of Sn Doped Zinc Oxide (ZnO:Sn) Thin Films Prepared by Spray Pyrolysis Method

Sn-doped zinc oxide (ZnO:Sn) thin films were deposited onto the ultrasonically cleaned pre-heated glass substrates by employing a simplified spray pyrolysis technique using a spray gun at a constant temperature 250oC. The films were deposited on the substrate for various solution volumes by taking 0.05M of Zinc acetate as precursor concentration along with 0.0001M 0.0003M Stannic chloride. The thickness of the films was calculated by the gravimetric weight difference method. The effects of Sn concentration on the structural and optical properties of films were investigated. The deposited films of Sn-doped ZnO showed that the films are c-axis oriented with hexagonal wurtzite structure and preserve their (002) preferential orientation. The grain sizes decreased depending on the increasing Sn concentration. From the optical spectra, all the film exhibits a better transparency of about 80% to 90% in the visible region along with a sharp absorption edge observed which is suitable for optoelectronic applications. The optical band gap slightly increases with increasing Sn doping concentration.  The electrical properties of the films show that the resistivity of the film decreases with the increase of Sn concentration with ZnO. The results suggest the potential application of Sn-doped ZnO thin film as a transparent conducting oxide layer for different optoelectronic and photovoltaic devices.