Oxygen Partial Pressure Dependence of the Properties of TiO2 Thin Films Deposited by DC Reactive Magnetron Sputtering

Thin films of TiO2 have been deposited on glass and silicon wafers (100) substrates by DC reactive magnetron sputtering from a 99.995% pure titanium target. The influence of the oxygen partial pressure on the optical, crystallinity, surface morphology and UV-induced hydrophilic properties has been studied. The films were characterized by UV-VIS spectrophotometer, X-ray diffractometer, atomic force microscopy and scanning electron microscope. The UV-induced hydrophilicity of the films was measured by the contact angle variation. The results showed that the crystalline anatase, anatase/rutile or rutile films can be successfully deposited on unheated substrate. The best hydrophilicity was obtained on the well-crystallized anatase TiO2 thin film deposition with 5.0×10-3 mbar oxygen partial pressure. The optical band gap of TiO2 thin films increased with increasing oxygen partial pressure,from 3.21 to 3.28 eV, with film thickness of 135 nm.