Characteristics of N-doped titanium oxide prepared by the large scaled DC reactive magnetron sputtering technique

N-doped TiO2 and TiO2 thin films were prepared by the DC reactive magnetron sputtering technique. Since sputtering system adopted in this experiment was specially designed to use the target with size of 200 mm × 500 mm, this system was made easy for practical application. It was observed that N2 addition reduced the hysteresis of the discharge voltage during sputtering of TiO2 onto substrate. Particle sizes doped on the glass surface were found to be 50–60 nm with cylindrical structures. Average surface roughness of N-doped TiO2 film was measured to be 15.9 Å, while that of TiO2 to be 13.2 Å. The binding energy of N 1s was measured at 398.9 and 394.9 eV by XPS. The XRD analysis represented that the films were mainly composed of anatase phase. Rutile phase was also observed in thin films annealed at above 400 °C. Red shift was observed under the given conditions. It seemed that added nitrogen and mixed crystal structure improved the photoactivity of TiO2 films in the range of visible light.