Synthesis and optical property of large-scale centimetres-long silicon carbide nanowires by catalyst-free CVD route under superatmospheric pressure conditions

Large-scale centimetres-long single-crystal beta-SiC nanowires have been prepared using CH4 as the carbon source and SiO or the mixture of Si and SiO2 as the silicon source by a simple catalyst-free CVD route under superatmospheric pressure conditions. The nanowries grown on ceramic boat or corundum substrates, with lengths of several centimetres and the average diameters of around 40 nm, were composed of single-crystal beta-SiC core along the [111] direction and amorphous SiO2 shell of about 1-30 nm thick depending on the growth position along the flowing direction of the carrier gas. The total gas pressure is an important factor for the synthesis of the large-scale centimetres-long beta-SiC nanowires, which can easily adjust the pressure of the vapors to supersaturation condition. The growth of the nanowires was governed by the Vapor-Solid mechanism. The beta-SiC nanowires showed an intense blue light emission at room temperature.