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

Abstract

We report a fabrication and characterization of ZnO, TiO2 and ZnO:TiO2 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, TiO2 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:TiO2 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 TiO2 (70%) and ZnO:TiO2 (35%) composite films. The absorbance edge shifted to the longer wavelength for ZnO:TiO2 composite film. The energy band gap of ZnO, TiO2 and ZnO: TiO2 composite were 3.8 eV, 3.6 eV and 3.5 eV, respectively.