Thin films of titanium oxide grown by oxidizing a Ti (0001) surface were characterized using XPS and UPS. The oxide films were easily reduced by thermal treatment. Annealing to 500K typically caused ≈20% of anionic vacancies. Evidence  was presented for the existence of anionic overlayers on the surface of TiO2 films that were stable at, or below, room temperature. Deposition of Pt or Au atoms on thin (few atomic layers) TiO2films at 80K resulted in diffusion of the deposited metals through the oxide to the metal-oxide interface. This result could be interpreted on the basis of the Cabrera-Mott theory for oxidation of metals at low temperatures.

Low Temperature Diffusion of Pt and Au Atoms through Thin TiO2 Films on a Ti Substrate. Ocal, C., Ferrer, S.: Surface Science, 1987, 191[1-2], 147-56