Self-assembled tungsten oxide nanowires by electron beam assisted rapid thermal annealing

We report on the fabrication of WO3 nanowires on Si (100) substrate using nickel catalyzed electron beam assisted rapid thermal annealing process. A 7 nm thick W layer deposited on the nickel coated substrate was annealed under high vacuum using electron beam (3 key) for 30, 60 and 90 s. The nickel activates the growth of tungsten nanowires with a high aspect ratio and subsequently is oxidized due to the high refractory nature of tungsten under exposure to oxygen gas. The resulting changes in surface morphology, oxidization state and elemental composition of WO3 nanowires were investigated systematically. The oxidization of metallic tungsten nanowire was found to depend on the annealing time. (C) 2011 Elsevier B.V. All rights reserved.