Photo-induced properties of thin TiO2 films deposited using the radio frequency plasma enhanced chemical vapor deposition method

Thin titanium oxide films were deposited with the help of radio frequency plasma enhanced chemical vapor deposition technique. The RF power of deposition was applied as the operational parameter of the process, and optical properties, transmittance in particular, of the films were utilized as criterion for their selection.Photo-induced properties of the films, including a change of water wettability under the effect of illumination and photocatalytic activity, were studied. A substantial decrease of water contact angle was observed upon the irradiation of the films with ultraviolet (UV) light. The largest increase of water wettability was obtained for the surfaces of the films exhibiting the highest value of index of refraction. Testing of the photo-catalytic activity of the titanium oxide films comprised UV light-induced decomposition of benzene and aniline dissolved in water and bactericidal action against the Escherichia coli strain DH5α. The largest bactericidal efficiency was observed in the case of the film characterized by the highest index of refraction. Auger Electron Spectroscopy measurements have shown that the film composition is that of a nearly stoichiometric TiO2, with a small chlorine contamination.