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Nitrogen doping was proposed recently as a low-cost means to shift the absorption edge of titania towards 450–500 nm. Results are reported here on the preparation of nitrogen-doped 250 nm thick TiO2 films on glass substrates by RF magnetron sputtering. The nitrogen content in the films was modified by changing the N2 partial pressure in the discharge from 0.00 to 0.27 Pa. An additional amount of oxygen was added in the deposition chamber (pO2 = 0.11 Pa) to compensate for oxygen depletion in the films. Surface composition and structure were derived from XPS and XRD data, respectively. XRD data revealed a mixture of amorphous phase and rutile polymorph in the as-deposited films, while an anatase-rich phase occurs in the samples deposited under N2 pressure of 0.05 and 0.16 Pa. Above 0.16 Pa, a rutile-rich phase is present. Surface wettability was investigated from contact angle data of de-ionized water with solid surface. The films deposited under mid-range N2 pressure in the discharge are super-hydrophilic. The photo-induced super-hydrophilicity decays after 36 h. Film wettability is discussed in terms of the synergic effects of surface roughness (measured by AFM) and rutile–anatase TiO2 phase transition, induced by doping. The TiO2 surface super-hydrophilicity (and catalytic efficiency) are related to beneficial properties of anatase phase (Eg = 3.2 eV), associated with a low recombination rate of charge carriers in the surface.

Fe-doped titania films were deposited by RF sputtering onto different substrates (glass and ITO/glass) in the same deposition run. The rutile nanocrystalline structure of Fe-doped thin films deposited on glass substrates and anatase nanocrystalline structure of Fe-doped thin films deposited on ITO/glass substrates were evidenced by XRD. SEM investigations showed a smooth surface with a dense nanostructure. XPS study evidenced an almost stoichiometric composition with different iron contents. EPR and XPS studies evidenced that iron entered into TiO 2 lattice by substitution, as isolated and dimer species. In Fe-doped thin films deposited on ITO/glass substrates the iron content is ten times higher than in Fe-doped thin films deposited on glass substrates and that a part of them entered as Fe 2+ .

Results are reported on the characterization of 200–250 nm thick TiO x transparent films grown at temperatures of 150 °C and 500 °C by reactive pulsed-laser ablation of a metallic Ti target under 0.13–13.3 Pa oxygen atmosphere. Film structure and composition were investigated by X-ray diffraction and X-ray photoelectron spectroscopy. The samples deposited at 150 °C reveal a mixture of amorphous TiO 2 and Ti 2 O 3 , irrespective of oxygen pressure. The O:Ti atomic ratio fluctuates in their surface around 1.83 for oxygen pressure ranging between 0.13 Pa and 2.66 Pa. The samples deposited at 500 °C feature different characteristics, as a function of oxygen pressure: (a) below 2.66 Pa of O 2 the films contain a mixture of significant amount of anatase and rutile TiO 2 phases, along with titanium suboxides; (b) above this threshold, the rutile phase vanishes, the anatase TiO 2 phase remaining dominant along with small amounts of nanocrystalline suboxides. The size of the anatase nanocrystallites decreases with the increase of oxygen pressures. The samples deposited at 500 °C feature a slight improvement of surface stoichiometry, from roughly TiO 1.8 to TiO 1.9 . The films deposited at high substrate temperature and oxygen pressure are highly hydrophilic.