Growth of rutile TiO 2 nanorods on anatase TiO 2 thin films on Si-based substrates
- PDF / 604,523 Bytes
- 7 Pages / 584.957 x 782.986 pts Page_size
- 30 Downloads / 305 Views
Shihhan Lo Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208
Kai Song The Northwestern University Atomic and Nanoscale Characterization Experimental Center, Northwestern University, Evanston, Illinois 60208
Baiju K. Vijayan Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois 60208
Wenyun Li The Northwestern University Atomic and Nanoscale Characterization Experimental Center, Northwestern University, Evanston, Illinois 60208
Kimberly A. Gray Department of Civil and Environmental Engineering, Northwestern University, Evanston, Illinois 60208
Vinayak P. Dravid Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208; and The Northwestern University Atomic and Nanoscale Characterization Experimental Center, Northwestern University, Evanston, Illinois 60208 (Received 6 April 2011; accepted 19 May 2011)
Synthesis of titania (TiO2) nanorods on various substrates has recently attracted attention for energy and environmental applications. Herein, we report growth of nanostructured TiO2 on Si(111) and glass borosilicate substrates by a two-step method. A thin film of anatase TiO2 was first laid down by spin coating and annealing, followed by the growth of rutile TiO2 nanorods with a hydrothermal method. To understand the role of the polycrystalline anatase TiO2 seed layer, we selected a relatively high temperature for the hydrothermal reaction, e.g., 175 °C at which no rutile TiO2 nanorods could grow without the precoated anatase TiO2 layer. The morphology and microstructure of both the polycrystalline anatase and rutile nanorod layers were characterized by electron microscopy and x-ray powder diffraction. Such a two-step fabrication method makes it possible to grow TiO2 nanorods on almost any substrate. I. INTRODUCTION
Titania (TiO2) is an important photoactive material with existing and potential uses in a wide variety of environmental and energy applications, such as photocatalytic oxidation of contaminants,1–4 photochemical water splitting under ultraviolet (UV) illumination,5,6 and dye-sensitized photovoltaic cells.7–9 Nanostructured TiO2 with different morphologies has attracted great interest since unique properties emerge as a function of the shape and structure of TiO2 nanomaterials.10–12 Among them, one-dimensional (1D) TiO2 nanowires and nanorods have been synthesized on various substrates by vapor evaporation methods, i.e., metal–organic chemical vapor deposition,13,14 thermal a)
Address all correspondence to this author. e-mail: [email protected] DOI: 10.1557/jmr.2011.190 1646
J. Mater. Res., Vol. 26, No. 13, Jul 14, 2011
http://journals.cambridge.org
Downloaded: 14 Mar 2015
evaporation,15,16 and oblique angle deposition.17 Periodic TiO2 nanorod arrays have been synthesized on Si substrate by pulsed laser deposition, where a monolayer of polystyrene being used as templates.18 Vapor phase techniques, which normally require high growth temperatures, have several l
Data Loading...
