Thermal effect on TiO2-doped ZnO thin film and its evaluation as a transparent electrode material

Abstract

There is a search for cleaner and sustainable lower cost transparent conductive oxide as an alternative to high cost and toxic indium tin oxide. This work examines post- deposition heat treatment properties of Titanium dioxide doped Zinc oxide as transparent conducting oxide.  Titanium dioxide doped Zinc oxide solution was deposited via spin -coating deposition technique and annealed to investigate annealing temperature effect on the properties. Characterization was done with UV -Vis spectroscopy, Scanning Electron Microscopy, and X-ray diffraction. Xray diffraction revealed that the films grow preferentially oriented in the (014) crystallographic direction of the Zinc Oxide grains. Optical transmittance of thin film annealed at 400 ⁰C was approximately 80% in the visible solar spectrum which suggests a highly suitable material for transparent conducting oxide applications. Optical band gap energies varies between 3.74 and 3.78 eV and a low electrical resistivity values 2.04 x 10 - 3 ῼ-cm to 3.12 x 10 - 3 ῼ-cm. Scanning Electron Microscopy  images show that the roughness and grain size of thin film increases with increase in temperature.