A new method has been developed to produce dense and highly aligned silica nanowires. Subliming In2O3 powder to a Si wafer coated with nickel (Ni) nanoparticles under N-2/NH3, highly aligned nanowires were produced in large quantities. The nanowires are of uniform diameters (10-20 nm) and lengths (5-20 mum). The aligned nanowires are also often self-assembled into a variety of elegant architectures. The discussion on the growth mechanism suggests that the nanowires were initiated from microballs (1-20 mum in diameter) of In-Ni alloys. The alignment of the nanowires was due to an overcrowding effect. (C) 2003 Elsevier B.V. All rights reserved.