Fast Growth of Highly Ordered TiO2 Nanotube Arrays on Si Substrate under High-Field Anodization

Highly ordered TiO2 nanotube arrays (NTAs) on Si substrate possess broad applications due to its high surface-to-volume ratio and novel functionalities, however, there are still some challenges on facile synthesis. Here, we report a simple and cost-effective high-field (90-180 V) anodization method to grow highly ordered TiO2 NTAs on Si substrate, and investigate the effect of anodization time, voltage, and fluoride content on the formation of TiO2 NTAs. The current density-time curves, recorded during anodization processes, can be used to determine the optimum anodization time. It is found that the growth rate of TiO2 NTAs is improved significantly under high field, which is nearly 8 times faster than that under low fields (40-60 V). The length and growth rate of the nanotubes are further increased with the increase of fluoride content in the electrolyte.Highly ordered TiO2 nanotube arrays (NTAs) on Si substrate have been fabricated by high-field anodization method. A high voltage (90-180 V) leads to a high growth rate of TiO2 NTAs (35-47 nm s-1), which is nearly 8 times faster than the growth rate under low fields (40-60 V). Furthermore, the current density-time curves recorded during the anodization provide a facial method to determine the optimal anodization parameters, leading to an easy obtaining of the desired nanotubes.