Optical parameter determination of ZrO2 thin films prepared by sol gel dip coating

Abstract : Zirconium Oxide (ZrO2) thin films were prepared on glass substrates by sol-gel dip coating method using Zirconium Oxychloride Octahydrate, Isopropanol and Acetyl acetone as precursor, solvent and stabilizer respectively. In the present work, the optical properties of the Zirconia thin films have been studied. Samples with different number of layers were prepared by repeating the dipping and drying processes. Then, the sol gel derived films were annealed at 500°C. The crystalline structure of the ZrO2 film was determined using X-ray diffraction. The films found to show tetragonal phases at the annealing temperature of 500°C. The UV-Visible transmission and reflectance spectra were used to observe the optical properties of the thin films. The average refractive index of the thin films was found to be 1.9, calculated using reflectance and transmission spectra. The measured band gap values of the ZrO2 thin films were nearly 4.8 eV. SEM analysis showed that the films have cracked plane morphology, as a result of their contraction during heat treatment.