High rate deposition of photocatalytic TiO 2 films by dc magnetron sputtering using a TiO 2 − x target

Photocatalytic TiO 2 films were deposited on glass substrates by dc magnetron sputtering using a slightly reduced TiO 2 − x target ( 2 − x = 1.986 ; conductivity, 3.7 S cm − 1 ; density, 4.21 g / cm 3 ). The variation in the deposition rate as a function of the O 2 flow ratio did not show a hysteresis curve at the “transition region” as seen in the case of a Ti metal target. The deposition rate using the TiO 2 − x target in 100% Ar gas was approximately seven times higher than that using the Ti metal target in an “oxide mode.” The films postannealed in air at temperatures ≥ 200 ° C showed excellent photodecomposition characteristics of acetaldehyde ( CH 3 CHO ) as well as photoinduced hydrophilicity.