Investigation of p-type SnO2:Zn films deposited using a simplified spray pyrolysis technique

Zinc doped SnO2 films were prepared using a simplified spray technique and the influence of dopant concentration on structural, electrical, optical and surface morphological properties were analysed in detail. XRD results showed that all the films were polycrystalline SnO2 with tetragonal rutile structure. The transition of preferential orientation from (2 1 1) to (1 0 1) plane was found to take place beyond 20 at.% of Zn doping level. Hall measurements showed that the films exhibited p-type conductivity when the doping concentration was increased beyond 20 at.%. The average transmittance of the SnO2:Zn films were in the range of 80-90% in the visible region. The enhancement in the PL emission can be correlated with the decrease in the grain size observed from the SEM images and the sharpening of defect related peaks supplemented the formation of trapped states (introduction of dangling bonds) at higher Zn concentrations.