Zirconium doped zinc oxide thin films grown by spray pyrolysis technique for TCO applications

Zirconium (Zr) doped Zinc Oxide (ZnO) thin films were grown on pre-cleaned glass substrates by spray pyrolysis technique. The dopant was added in different concentrations to study its influence on the structural, optical, morphological, and electrical properties of ZnO thin films. X- Ray Diffractogram (XRD) data was used to study the structural properties of all the thin films. It was found that the crystallite size varied between 25 and 45 nm for dopant at different concentrations. Additionally, it was discovered that ZnO possessed a hexagonal wurtzite structure with (002) as its preferred orientation regardless of the doping doses. The optical properties for all the thin films were obtained by analysing the absorption spectra. The transmittance of all the thin films ranged between 65 % and 86 % in the visible range with 4 at % Zr doped ZnO having highest transmittance. Scanning Electron Microscopy (SEM) results showed the agglomeration of particles at higher concentrations of the dopant. Electrical studies showed that the resistivity of the doped samples decreased as compared to the pristine sample. Sample with 6 % of doping had the highest carrier concentration and hence, showed the least resistivity of 67 ohm cm.