Alina Manole

PHOTOINDUCED WETTABILITY OF TITANIUM OXIDE THIN FILMS

We present here the results of a systematic investigation of the influence of the main deposition parameters (substrate temperature, deposition time, reactive gas composition, etc.) on the hydrophilic properties of DC sputtered titania films, grown on heated glass substrates (463−573 K), using water vapors as the reactive gas. Reference samples prepared in standard oxygen-based deposition conditions were used to compare the results. All the investigated samples were polycrystalline, with either pure anatase or mixed anatase-rutile nano-phase mixtures, depending on substrate temperature and film thickness. The surface wettability, evaluated from contact angle data during UV irradiation and in the back-reaction conditions, is discussed in terms of the synergic effects of materials structure, surface morphology, elemental composition, and electronic properties.

Characterization of Rutile N-Doped TiO2 Films Prepared by RF Magnetron Sputtering

Rutile N-doped TiO2 thin films were grown by RF magnetron sputtering on amorphous and crystalline substrates at room temperature. The surface elemental analysis, investigated by X-ray photoelectron spectroscopy indicated that the nitrogen content of the films could be adjusted up to values as high as 4.1 at.%. As demonstrated by the X-ray diffraction data, the as-deposited films (100 200 nm thick) showed no detectable crystalline structure, while after successive annealing in air for one hour at 400°C, 500°C and 600°C, the (110) rutile peaks occurred gradually as dominant features. The rutile phase in the films was confirmed by the band gap values of the deposited materials, which stabilized at 3.1 eV, for the thin films having 200 nm thicknesses.