Interface reactions of Ag@TiO2 nanocomposite films

TiO2 films were sputtered on 100-nm-thick Ag layers at various O2 partial pressures to study forming processes at the interface. The interfacial reactions during the deposition process were investigated by means of transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, atomic force microscopy and UV-vis reflection spectra. The sputtering process led to formation of Ag nanoparticles surrounded by Ag2O and TiO2 in the TiO2 film matrix as well as on the surface. The presence of oxygen in the plasma resulted in enrichment of silver oxides on the surface and an intermixing of Ag in the TiO2 matrix. The film structures could be explained based on the interplay among the formation of silver oxide, the nucleation and growth of TiO2, as well as the mobility of silver and silver oxides within the growing TiO2 films.