The photocatalytic activity and photoconductive characteristics of hydro-oxygenated amorphous titanium oxide (a-TiOx:OH) films prepared using remote plasma enhanced chemical vapor deposition (RPE-CVD) were studied. The a-TiOx:OH films have OH groups, which when exposed to UV irradiation, show high photoconductivity. The photoconductivity is drastically affected by oxygen gas. The results suggest that the recombination states present in the film are non-activated by the OH. endings in the dangling bond like the hydrogen endings in hydrogenated amorphous silicon. Oxygen-sensitive photoconductivity is useful for environmental sensor applications. (c) 2004 Elsevier B.V. All rights reserved.