Growth of SiO2 nanowires on different substrates using Au as a catalyst

SiO2 nanowires were prepared on a SiO2/Si(111) or Si substrate using Au as a catalyst. The products were characterized using scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). SEM shows that large amounts of SiO2 nanowires with a diameter of 20-150 nm and length of several nanometers were formed on the entire surface of the substrate. XPS analysis indicates that the nanowires have the composition of Si and O in an atomic ratio of about 1 : 2, and their composition approximates that of SiO2. The formation of the SiO2 nanowires was controlled by the vapor-liquid-solid mechanism. It is found that the annealing time affects the morphology of the products. Finally, the effect of the substrates on the growth of SiO2 nanowires was discussed. The Si source of the SiO2 nanowires comes from the substrate or Si powder for different substrates.