Characterization of electronic properties of TiO2 nanotube films

By anodization of titanium, TiO2 nanotube layers were grown that consist of arrays of individual tubes with a length of ≈2.5 μm, a diameter of ≈100 nm and a wall thickness of ≈15 nm. The electronic properties of TiO2 nanotube layers were characterized using photoelectrochemical and impedance measurements. Photocurrents for as-anodized tubes are dominated by their amorphous state and a high number of defects. Conversion to anatase by annealing decreases the defect density drastically which results in an enhanced photocurrent.