Photoelectric properties of TiO2-ZrO2 thin films prepared by sol-gel method

Acidic sols of TiO2, ZrO2 and Ti-Zr mixed oxide precursors were prepared. The sols were then smeared on quartz substrate and annealed at 650 degrees C for 2 hour to form polycrystalline oxide films. XRD, SEM, UV-visible absorption spectra and XPS were carried out to characterize the films. It was found that the crystalline phase of pure titania is an anatase and pure zirconia is a tetragonal. The binary oxides show the anatase phase at the molar ratio of Ti:Zr = 2.73:1, which means that solid solution was formed. The absorption edge of the TiO2-ZrO2 binary oxides showed obvious blue shift as the Zr ratio increased. The results obtained indicate that the band gap of the binary oxides could be adjusted from 3.2 eV (TiO2) to 7.8 eV (ZrO2) by varying the molar ratio of Ti and Zr. Au interdigitated electrodes were produced by planar technology and MSM (metal-semiconductor-metal) structure UV detector based on TiO2-ZrO2 binary oxides was fabricated. Obvious photoelectric response was observed.