Growth of rutile TiO2 nanorods on TiO2 seed layer prepared using facile low cost chemical methods

Dense rutile TiO2 nanorods were grown on an anatase TiO2 seed layer by a wet-chemical approach in which the nuclei layer was prepared by the chemical spray pyrolysis technique. Structural, morphological, and optical properties of prepared samples were investigated using X-ray diffraction (XRD), micro-Raman, scanning electron microscopy (SEM), atomic force microscopy (AFM), UV-vis spectroscopy, and fluorescence spectroscopy. From XRD, a clear authentication that, the preferentially oriented (101) crystallographic planes indicate that the rutile TiO2 nanorods are standing randomly along the normal to the substrate surface. Anatase TiO2 seed layer and rutile nanorods structural phases are clearly confirmed by micro-Raman measurement. SEM and AFM studies reveal that the TiO2 seed layer consists of high density nanoparticles with the thickness of 0.15 mu m and the height of the as-grown nanorods is similar to 0.6 mu m. The band gap energy of the anatase TiO2 seed layer and rutile as-grown nanorods is calculated using UV-vis absorption spectra and the band gap values of seed layer and nanorods are 3.21 eV and 2.95 eV respectively. The crystal defects of prepared films are measured using photoluminescence spectra. (C) 2013 Elsevier B.V. All rights reserved.