Highly ordered TiO2 nanotube arrays were fabricated via electrochemical anodization of high purity Ti foil and Ti thin film coated indium tin oxide (ITO) glass in fluorine containing electrolytes (both aqueous and nonaqueous). The formation of ordered TiO2 nanotube arrays was affected by the electrolyte temperature and the applied anodization potential. In aqueous electrolyte, the anodization potential exerted significant influence on the formation of TiO2 nanotube arrays, while little effect from the electrolyte temperature was observed. In nonaqueous electrolyte, the electrolyte temperature markedly affected the TiO2 nanotube dimensions, while the anodization potential exhibited slight influence in this regard. As a consequence, TiO2 nanotube arrays with tube diameters ranging from 20 to 90 nm and film thicknesses ranging from several hundred nanometers to several micrometers were obtained. The TiO2 nanostructures were examined by scanning electron microscopy. Thermal annealing on the anodized Ti induce...