Fabrication and optical properties of TiO2 nanowire arrays made by sol-gel electrophoresis deposition into anodic alumina membranes

Ordered TiO2 nanowire arrays have been successfully fabricated into the nanochannels of a porous anodic alumina membrane by sol-gel electrophoretic deposition. After annealing at 500 deg. C, the TiO2 nanowire arrays and the individual nanowires were characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and x-ray diffraction (XRD). SEM and TEM images show that these nanowires are dense and continuous with a uniform diameter throughout their entire length. XRD and SAED analysis together indicate that these TiO2 nanowires crystallize in the anatase polycrystalline structure. The optical absorption band edge of TiO2 nanowire arrays exhibits a blue shift with respect of that of the bulk TiO2 owing to the quantum size effect