FORMATION OF A TITANIUM-DIOXIDE NANOTUBE ARRAY

Starting from the naturally occurring structure of porous aluminum oxi de, a polymer mold suitable for the formation of titanium dioxide nano tubes was obtained. The tubular structure was formed by electrochemica l deposition in the mold. After dissolution of the polymer, titanium d ioxide nanotubes were obtained and characterized. The ''as deposited'' TiO2 tubes were amorphous, but polycrystalline anatase samples of the same structure were obtained after heat treatment. The inner diameter of the tubes decreased from about 100 to 70 nm during the crystalliza tion. A mechanism for the electrochemical deposition is proposed. Furt hermore, the preparation procedure could also be applied to other semi conducting materials.