A simple method based on the thermal oxidation of Si wafers has been discovered to provide a large-scale synthesis of very long, aligned silica nanowires. The as-grown product was characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, and photoluminescence. The obtained SiO2 nanowires had no metal contaminations, ultralong lengths of millimeters, and most diameters of similar to50 nm. The PL spectra of the SiO2 nanowires showed a strong and stable green emission at 540 nm. The nucleation and growth of the SiO2 nanowires were investigated. (C) 2002 Elsevier Science B.V. All rights reserved.