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Journal of Nanomaterials
Volume 2008, Article ID 957935, 5 pages
http://dx.doi.org/10.1155/2008/957935
Research Article

Ambient Pressure Synthesis of Nanostructured Tungsten Oxide Crystalline Films

1Department of Physics, University of Puerto Rico, P.O. Box 23343, San Juan, PR 00931, USA
2Department of Physics, Donghua University, Shanghai 200051, China

Received 5 March 2008; Accepted 28 April 2008

Academic Editor: Rakesh Joshi

Copyright © 2008 H. X. Zhang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

We report the results of the ambient pressure synthesis of tungsten oxide nanowires and nanoparticles on AlN substrates using the hot filament CVD techniques. The morphologic surface, crystallographic structures, chemical compositions, and bond structures of the obtained samples have been investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and Raman scattering, respectively. Different morphologies were observed for different substrate temperatures, but otherwise identical growth conditions. The experimental measurements reveal the evolutions of the crystalline states and bond structures following the substrate temperatures. Besides, different substrate materials also affected the tungsten oxide nanostructures. Bundles of wire-type tungsten oxide nanowires with a length of up to 5 mm were obtained on substrate. Furthermore, the sensitive properties of the super long nanowires to the gas and different temperature were investigated. The dependence of the sensitivity of tungsten oxide nanowires to the methane as a function of the time was obtained. The sensitive properties of the tungsten oxide nanowires have almost linear relationship with the temperature.