Nanocrystal TiO 2 films were prepared by radio frequency (RF) sputtering technique and coating method, respectively. The samples were treated by Ar RF plasma. The crystal structure, absorption spectra and morphology of the TiO 2 films were investigated by X-ray diffraction (XRD), UV–VIS spectrophotometry and atomic force microscopy (AFM). The voltages and photo-currents of the TiO 2 electrodes were also measured. By Ar plasma treatment, the photo-currents of the sputtered and coated TiO 2 electrodes increased by 80% and 60%, respectively.
