Formation of silicon oxide nanowires directly from Au/Si and Pd-Au/Si substrates

Amorphous silicon oxide (SiOx) nanowires were directly grown by thermal processing of Si substrates. Au and Pd-Au thin films with thicknesses of 3 nm deposited on Si (0 0 1) substrates were used as catalysts for the growth of nanowires. High-yield synthesis of SiOx nanowires was achieved by a simple heating process (1000-1150 °C) in an Ar ambient atmosphere without introducing any additional Si source materials. The as-synthesized products were characterized by field-emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy measurements. The SiOx nanowires with lengths of a few and tens of micrometers had an amorphous crystal structure. The solid-liquid-solid model of nanowire formation was shown to be valid.