Fast formation of thick and transparent titania nanotubular films from sputtered Ti

Ti films sputtered on transparent fluorine-doped tin oxide glass substrates were anodized in fluoride-containing organic electrolyte in the presence of H2O. In this work, anodic TiO2 nanotubes (ATNs) as long as 9.2 ± 0.3 μm were obtained with high growth rate of 0.64 ± 0.3 μm min−1. We demonstrated the optimum anodization conditions for ATN growth on foreign substrates, were within the range of 0.3–0.5% (wt) NH4F, with 3–5% (vol) H2O at 60 V. XPS and ICP-MS were utilized to elucidate the increase of thickness and volume expansion obtained from the sputtered Ti film to their ATN forms. The ATN films exhibited excellent uniformity and adhesion to the substrates.