Self-ordering electrochemical synthesis of TiO2 nanotube arrays: controlling the nanotube geometry and the growth rate

Abstract

We report the fabrication of highly ordered TiO₂ nanotube arrays employing electrochemical anodization of titanium using an organic electrolyte comprised of water, NH₄F, and ethylene glycol. To achieve the self-ordering regime of TiO₂ nanotube growth and reliable fabrication optimal potential window between 80 and 100 V was determined. We show that anodization voltage can be used not only to control nanotube diameters (70-180 nm) but also to have impact on nanotube growth rate. The anodization voltage and anodization time were used to adjust the length of TiO₂ nanotube (thickness of nanotube layer). TiO₂ nanotube array films and self-supporting layers with thickness from < 5 micrometers to > 250 micrometers were routinely fabricated