Fabricating TiO2 Photocatalysts by rf Reactive Magnetron Sputtering at Varied Oxygen Partial Pressures

Titanium dioxide (TiO2) thin films were fabricated onto non-alkali glass substrates by rf reactive magnetron sputtering at room temperature using Ti-metal target at varied oxygen partial pressure [O2/(Ar + O2)]. The sputtering deposition was performed under an rf power of 200 W. The target to substrate distance was kept at 80 mm, and the total gas pressure was 10 mTorr after 2 h of deposition. It was found that the crystalline structure, surface morphology, and photocatalytic activities of the TiO2 thin films were affected by the oxygen partial pressure during deposition. The XRD patterns exhibited a broad-hump shape indicating the amorphous structure of TiO2 thin films. The thin films deposited at a relatively high value of oxygen partial pressure (70%) had a good photo-induced decomposition of methylene blue (MB), photo-induced hydrophilicity, and had a small grain size.