The thermal atomic layer deposition (Th-ALD) of TiO2 films on stainless steel for use as a photocatalyst was investigated and compared to plasma-enhanced ALD (PE-ALD) using the same precursor. Th-ALD TiO2 films were deposited on stainless steel using a Ti(NMe2)(4) [tetrakis(dimethylamido)Ti,TDMAT] precursor. The microstructure of the Th-ALD TiO2 films was greatly dependent on the growth temperature as an amorphous structure was obtained at 200 degrees C and a polycrystalline structure was achieved at temperatures above 300 degrees C. From the contact angle measurement of water, the crystalline TiO2 films exhibited super-hydrophilicity after UV irradiation. The anatase phase of both the Th- and PE-ALD TiO2 films grown on stainless steel showed higher photocatalytic abilities than the rutile phase grown at 400 degrees C. In addition, the anatase PE-ALD TiO2 film demonstrated a higher photocatalytic efficiency than the Th-ALD films. The photocatalytic efficiency of the Th-ALD TiO2 films was investigated as a function of film thickness and it was found that the efficiency was saturated above a film thickness of 120 nm. (C) 2011 Elsevier B.V. All rights reserved.