Growth and photo-electrochemical properties of rutile TiO₂ nanowire arrays prepared by the hydrothermal method

Abstract Rutile TiO2 nanowire arrays have been synthesized on a fluorine-doped tin oxide (FTO) coated glass substrate by a hydrothermal method. The effect of synthetic parameters on the morphology and initial growth mechanism have been investigated by X-ray diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy and selected area electron diffraction. Titanium n-butoxide concentration in the precursor solutions and growth temperatures are important parameters for synthesizing TiO2 nanowires. Although the FTO glass substrate showed the preferred orientation in (110), (101) and (200) faces of rutile SnO2, [001]-oriented TiO2 nanowire arrays were grown. Lattice matching between FTO and TiO2 is important for the initial nucleation and subsequent growth process. The anisotropic growth of TiO2 nanowire arrays along the [001] direction can be understood from the viewpoints of surface energy and growth rate of rutile TiO2.