Fabrication of oxide nanostructures on glass by aluminum anodization and sol–gel process

A novel process of fabricating various oxide nanostructures on glass substrates is described. Transparent porous alumina films (∅ 6–150 nm) were first formed in acid solutions by anodization of aluminum layers sputter-deposited on a glass plate coated with a tin-doped indium oxide film. The porous alumina structures after pore-widened were then used as a host or a template in a sol–gel process to synthesize hollow or solid titania nanostructures within the nanopores, depending on the pore size of films and the affinity of the TiO2 gel to alumina films. Finally, titania nanotubules (∼∅ 200 nm) or nanofibers (∼∅ 50 nm) arrays on glass were fabricated after the anodic alumina films were selectively removed.