Visible light activity of nitrogen-doped TiO2 thin films grown by atomic layer deposition

This article demonstrates that a visible light active N-doped TiO2 film can be fabricated by atomic layer deposition (ALD) with titanium chloride and ammonia water as the precursors. A 1.60 atom % N-doping anatase TiO2 film has been successfully grown on an n(+)-silicon substrate. The ratio of substitutional N doping to the total N doping as high as 70% is achieved that extends the long-wavelength cutoff of TiO2 to 550 nm. Results from the analysis of incident photon-to-current efficiency and potential-dependent photocurrent density suggest that the visible light activity of ALD N-doped TiO2 films can be further improved by reducing the carrier recombination rate and increasing optical absorption efficiency. (C) 2008 The Electrochemical Society.