Fabrication, characterization and Raman study of TiO2 nanowire arrays prepared by anodic oxidative hydrolysis of TiCl3

Highly ordered TiO2 nanowire arrays were prepared in anodic alumina membranes by anodic oxidative hydrolysis of TiCl3. The TiO2 nanowires are polycrystalline anatase-phase with uniform diameters around 50 nm and are composed of very small crystallites with diameters of about 2–4 nm. After annealing the crystallites grow to about 7 nm in diameters. At room temperature, Raman measurements of the TiO2 nanowire arrays show typical anatase TiO2 Raman spectra with significant broadening and shift, which can be attributed to phonon size confinement and oxygen deficiency.