Characterization of TiO2 nanotube arrays prepared via anodization of titanium films deposited by DC magnetron sputtering

Highly ordered TiO 2 nanotube arrays were fabricated on a conducting glass substrate in NH 4 HF 2 /glycol electrolyte via anodization of titanium film which was deposited by direct current magnetron sputtering (DCMS) at different temperatures. The results showed that Ti films with good homogeneity and high denseness could be formed under the conditions Ar pressure 0.35 Pa, direct current 3.5 A, and 2 h at 300 °C. Characterization of the TiO 2 nanotube arrays was investigated comparatively, by altering anodization time. The surface morphology of the samples changed as the anodization time was prolonged from 10 to 150 min at 30 V. The TiO 2 thin film was amorphous and could be transformed into anatase by annealing at 450 °C. On the basis of UV–visible transmission spectra the bandgap of the thin film was calculated to be 3.12 eV, and its tail extended to 2.6 eV.