Fabrication of zinc indium oxide thin films and effect of post annealing on structural, chemical and electrical properties

Abstract

In the present study, zinc indium oxide (ZIO) thin films were deposited on glass substrate with varying concentration (ZnO:In2O3 – 100:0, 90:10, 70:30 and 50:50wt.%) at room temperature by flash evaporation technique. These deposited ZIO films were annealed in vacuum to study the thermal stability and to see the effects on the structural, chemical and electrical properties. The XRD analysis indicates that crystallization of the ZIO films strongly depends on concentration of In2O3 and post annealing where annealed films showed polycrystalline nature. The surface morphological study of the films using scanning electron microscopy (SEM) revealed the formation of nanostructured ZIO thin films. The surface composition and oxidation state were analyzed by X-ray photoelectron spectroscopy. XPS spectra shows that as the concentration of In2O3 increases from 10 to 50wt%, the surface composition ratio In/Zn and O/Zn increases for as-prepared and annealed ZIO films while the XPS valance band spectra manifest the electronic transitions. The electrical resistivity was found to be decreased while carrier concentration and Hall mobility increased for both types of films with increasing concentration of In2O3.