Optical Properties of ZnO, TiO₂ and ZnO:TiO₂ Composite Films

Abstract

We report a fabrication and characterization of ZnO, TiO 2 and ZnO:TiO 2 composite thin films. The films were prepared on glass substrates by using the dip coating sol-gel method. ZnO was synthesized by using Zinc acetate dehydrated, glacial acetic acid and ethanol. Meanwhile, TiO 2 was prepared by using titanium isopropoxide, acetic acid, isopropyl alcohol and methanol. The single sols were mixed with fixed molarity of 0.2 mol to obtain ZnO:TiO 2 composite films. The optical properties of metal oxide, such as transmittance, absorbance and band gap were determined using UV-Vis spectrometer. FTIR was used to determine the chemical bonds of the materials. ZnO has the highest transmittance spectra (91%), followed by TiO 2 (70%) and ZnO:TiO 2 (35%) composite films. The absorbance edge shifted to the longer wavelength for ZnO:TiO 2 composite film. The energy band gap of ZnO, TiO 2 and ZnO: TiO 2 composite were 3.8 eV, 3.6 eV and 3.5 eV, respectively.