Structure and properties of nitrogen-doped titanium dioxide thin films grown by atmospheric pressure chemical vapor deposition

Using TiCl4, O2, and N2O as precursors, N-doped titanium dioxide thin films with large area and continuous surface were obtained by atmospheric pressure chemical vapor deposition. Measurements of X-ray photoelectron spectroscopy, X-ray diffraction, scanning electron microscope, transmission electron microscope and ultravoilet-Visible transmission spectra were performed. Using N2O as N-doped source, anatase-rutile transformation is accelerated through oxygen vacancies formation, and the mean grain size of rutile crystallites decreases with the increase of N2O flow rate. Compared to the pure TiO2, N-doped TiO2 films give a relative narrow optical band-gap, and their visible-light induced photocatalysis is much enhanced. Visible-light-induced hydrophilicity of the TiO2 thin films enhances with the increase of N2O flow rate, which might be due to the dentritic islands structure on the surface of the N-doped TiO2 thin films.