Anodic formation of highly ordered TiO2 nanotube arrays on conducting glass substrate: Effect of titanium film thickness

Abstract

Articles you may be interested inTiO2 nanotube arrays for photocatalysis: Effects of crystallinity, local order, and electronic structure J. Vac. Sci. Technol. A 33, 021202 (2015); 10.1116/1.4902350Band gap structure modification of amorphous anodic Al oxide film by Ti-alloying Appl. Phys. Lett.Research on the effect of crystal structures on W-TiO2 nanotube array photoelectrodes by theoretical and experimental methodsHighly ordered TiO 2 nanotube arrays were successfully fabricated using ammonium fluoride electrolyte by galvanostatic anodization technique. The nanotube arrays were grown perpendicular to the titanium film deposited onto conducting glass substrate. The effect of the different titanium film thicknesses on the morphology, optical, and electrical properties of TiO 2 nanotube arrays is investigated. It is found that the titanium film thickness is a crucial parameter for achieving highly ordered TiO 2 nanotube arrays. Morphological investigations on the nanotube arrays reveal that anodization of 1.5 lm thick titanium films leads to formation of pores at the upper layer of the film with nonuniform pore size distribution and poor interconnectivity. Instead, anodization of 2.5 and 2.0 lm thick titanium films with the same conditions leads to formation of highly ordered TiO 2 nanotube arrays with uniform size and sharp clear tubular structures, which are well connected to each other. The absorbance and optical band gap of the TiO 2 nanotube arrays are also inferred from the diffuse reflectance spectra.