Electrochemical synthesis of self-organized TiO crystalline nanotubes without annealing.

This work demonstrates that upon anodic polarization in an aqueous fluoride-containing electrolyte, TiO nanotube array films can be formed with a well-defined crystalline phase, rather than an amorphous one. The crystalline phase was obtained avoiding any high temperature annealing. We studied the formation of nanotubes in an HF/HO medium and the development of crystalline grains on the nanotube wall, and we found a facile way to achieve crystalline TiO nanotube arrays through a one-step anodization.