Nitrogen doped TiO2 films for hydrogen generation and optoelectronic applications

N:TiO2 thin films were sputtered on glass, Si(100) and FTO substrates at various nitrogen to total reactive gas flow ratio (eta). Tetragonal anatase phase were indexed for all prepared films. The incorporation of nitrogen into the TiO2 film did not have significant influence on the crystal structure. Slight decrease in the peak intensities and grain sizes was observed with increasing nitrogen ratio. The reduction of the UV-Vis-NIR transmittance and the elevation of reflectance coincided with the nitrogen content. The optical band gap (E-g) of the indirect transition was reduced from 3.35 to 3.04 eV with rising eta from 0 to 0.95. Nitrogen incorporation also had a great effect on the refractive index (n) and extinction coefficient (k). The results of measuring the chopped and continuous photocurrent densities under light irradiation leaded to examine the photoelectrochemical process for sewage water splitting of N:TiO2 films. The photocurrent density enhances with increasing nitrogen content up to eta = 0.75, above which a decrease in photocurrent is observed.