Indium-Doped ZnO Transparent Thin Films Deposited by Sol-Gel Dip Coating Method

Indium-doped zinc oxide (IZO) thin films were deposited onto glass substrates by sol-gel dip coating method with variation of doping concentration from 0.5 to 5% using Indium (III) acetate and Zinc(II) acetate as starting precursors for In and Zn sources, respectively followed by calcinations. Effect of doping concentration on the structural, morphological, and optical properties of IZO transparent thin films were investigated by relevant characterization including X-ray diffraction (XRD), scanning electron microscope (SEM), and optical spectroscopy. XRD spectra show the polycrystalline of hexagonal wurtzite structure of as-prepared films. IZO films with high doping concentration condition exhibit significant deterioration in their crystallinity. The crystalline size of the deposited thin films can be estimated by the calculation of the broadening of characteristic XRD peaks. IZO thin films show high optical transmittance in visible range without significant change in their optical band gaps with variation in In doping composition. Possible mechanisms taking responsibility on these features are mentioned and discussed.

Keywords: In-doped ZnO thin film, Sol-gel dip coating, Indium doping

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