Amorphous silica nanowires grown by the vapor–solid mechanism

Silica nanowires were synthesized by using silica nanoparticles as a growth catalyst using a gas composed of CH4 and H2 at 1050 °C. Silica nanoparticles provide silicon and oxygen atoms for the formation of the nanowires, as well acting as a growth site. The nanowires nucleated on graphitic carbon layers formed around the seed particles, indicating that the nanowires grow by the vapor–solid mechanism. Photoluminescence spectra of the nanowires normally showed strong blue emission peaked at 3.1 and 2.8 eV under 3.8 eV laser excitation. Post-hydrogen annealing resulted in the appearance of longer wavelength photoluminescence band.