AFM and XPS Study of Glass Surface Coated with Titania Nanofilms by Sol-Gel Method

Ce³⁺-doped and undoped TiO₂ nanofilms are prepared on glass surface using a sol-gel method. Crystal structure, surface morphology, chemical composition and element distribution of both glass substrates and TiO₂ films were characterized by x-ray diffractometer (XRD), atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS). The XRD results indicate that the Ce³⁺-doped TiO₂ films are solely composed of the anatase phase whereas in the undoped films a small amount of the rutile phase of TiO₂ is present. AFM observations show that there exist many micro-cracks and micro-holes on glass substrate surface. In contrast, the surface of pure titania films is crack-free and the average crystallite size of the films is less than 50 nm. For the films doped with Ce³⁺, not only does it appear to be more uniform and compact, but also the corresponding crystal size is decreased. XPS results indicate that element interdiffusion occurs between the titania nanofilm and the glass substrate during the sintering process. The film is firmly adhered onto the glass surface through the chemical combination of Ti-O-Si bonds, and the combination is more enhanced by Ce³⁺-doping.