Growth of silica nanowire arrays by reaction of Si substrate with oxygen using Ga as catalyst

Silica nanowire arrays were grown by oxidizing Si substrates with Ga catalyst in temperatures of 520-900 °C. The Si substrates, painted with a layer of molten Ga, were placed on a quartz boat, and heated up in a tube furnace. At high temperatures, Ga atoms condense into spheres, along with a small amount of silicon atoms. Si-O-Ga then formed on the surface of Ga-Si alloy sphere, and silica nanowire arrays were eventually grown with typical diameters of about 15-20 nm. A growth model based on extended vapor-liquid-solid mechanism is suggested.