OPTICAL-PROPERTIES OF SOL-GEL SPIN-COATED TIO2 FILMS AND COMPARISON OF THE PROPERTIES WITH ION-BEAM-SPUTTERED FILMS

Transparent and optical-grade TiO2 coatings were prepared by sol-gel spinning and ion-beam sputtering techniques. We investigate process parameters for the fabrication of sol-gel spin-coated TiO2 films exhibiting high optical quality comparable with that of ion-beam-sputtered TiO2 films. X-ray diffraction studies showed the sol-gel-deposited films to be amorphous for heat treatments below 350-degrees-C, whereas the ion-beam-sputtered films were slightly crystalline and exhibited the anatase structure. The refractive index and the extinction coefficient were evaluated from transmittance characteristics in the ultraviolet, visible, and near-infrared regions. Transmission spectra and ellipsometric measurements showed that spin-coated films were essentially optically equivalent to those prepared by ion-beam sputter deposition.