Photo-Functional Properties of TiO2/W-TiO2/TiO2 Thin Films Prepared by Reactive Magnetron Sputtering

Abstract

TiO2/W-TiO2/TiO2 thin film has been fabricated by reactive magnetron sputtering process with various TiO2 surface layer thicknesses. Doping of W was carried out to enhance the photocatalytic property of TiO2 in the visible light and the electrical properties of TiO2 thin film. Surface TiO2 layer with various thicknesses was suggested to avoid the decline that occurs in crystal structure with W doping. A methylene blue inundation test was used to measure the photocatalytic property. After light irradiation, sterilization and artificial sunlight lamp, for 6 hours; the difference in light absorbance at 665 nm wavelength was measured by using a spectrophotometer (SHIMADZU UV-2550) X-ray diffractions patterns (XRD: MAC science High quality XG M18XCE) with CuKα (0.154 nm) radiation at an incident angle of 0.3° and X-ray photoelectron spectroscopy (XPS) were employed to examine films structure and films composition, respectively. Surface layer thickness was changed from 10 to 50 nm. Maximum photocatalytic effectively obtained under sample with surface layer above 30 nm. The improving in photocatalytic property under artificial sun light lamp occurred because of light absorbance shifting to the positive side. However, the impurities cause defects in TiO2 structure and make the effect of photocatalytic under UV irradiation less than as deposited TiO2. In this study the surface layer was suggested to put off these defects.