Amorphous silica nanowires (a-SiONWs) were produced by direct solid state transformation from silica films. The silica nanowires grow on TiN/Ni/SiO2/Si substrates during the annealing in H-2 or a H-2:CH4 mixture at 1050 degreesC. Titanium nitride (TiN) films were used to induce a solid state reaction with silica (SiO2) films on silicon wafers to provide silicon atoms into growing nanowires. The TiN layers induce the diffusion of silicon and oxygen to the surface by a stress gradient built inside the films. The nickel diffuses to the surface during the TiN deposition and acts as a nucleation site for the a-SiONWs. (C) 2003 Elsevier B.V. All rights reserved.