Photoconductivity studies on amorphous and crystalline TiO2 films doped with gold nanoparticles

In this work, amorphous and crystalline TiO 2 films were synthesized by the sol–gel process at room temperature. The TiO 2 films were doped with gold nanoparticles. The films were spin-coated on glass wafers. The crystalline samples were annealed at 100°C for 30 minutes and sintered at 520°C for 2 h. All films were characterized using X-ray diffraction, transmission electronic microscopy and UV-Vis absorption spectroscopy. Two crystalline phases, anatase and rutile, were formed in the matrix TiO 2 and TiO 2 /Au. An absorption peak was located at 570 nm (amorphous) and 645 nm (anatase). Photoconductivity studies were performed on these films. The experimental data were fitted with straight lines at darkness and under illumination at 515 nm and 645 nm. This indicates an ohmic behavior. Crystalline TiO 2 /Au films are more photoconductive than the amorphous ones.