Synthesis and microstructure of metal oxide thin films containing metal nanoparticles by liquid phase deposition (LPD) method

Au nanoparticles dispersed SiO2-TiO2 composite films have been prepared by a novel wet process, Liquid Phase Deposition (LPD) method. The composite films were characterized by XRD, XPS, TEM, ICP, SEM and UV-VIS absorption spectroscopy. The results showed that the SiO2-TiO2 composite films containing Au-III and Au-I ionic species were co-deposited from a mixed solution of ammonium silicofluoride, ammonium hexafluorotitanate, boric acid and tetrachloroauric acid. The heat treatment induced the reduction of Au ions and formation of Au nanoparticles in the film. TEM observation revealed that tho Au nanoparticles with 5-10 nm in diameter were found to be dispersed uniformly in the SiO2-TiO2 matrix. The optical absorption band due to the surface plasmon resonance of dispersed Au particles were observed at the wavelength of 550 run and shifted toward longer wavelength with increasing heat treatment temperature.