Synthesis of large-scale SiC@SiO2 nanowires with good optical properties by using Si@SiO2 as silicon source

A simple and convenient method was developed for the preparation of a large number of high-purity cotton-like SiC@SiO2 nanowires by thermal evaporation without any catalyst. The Si particles with loose and discontinuous SiO2 coating (marked as Si@SiO2) were prepared by wet oxidation process as the source of silicon, and the high-purity graphite sheets were used as carbon sources. The large-scale of high purity SiC@SiO2 nanowires, which were over 100 μm in length and about 100 nm in diameter, were synthesized by the form of layers assembly of the graphite substrate according to the distribution of gas. The SiC@SiO2 nanowires have high crystallinity with flat and smooth surfaces. The synthesized SiC@SiO2 nanowires include single crystal 3C structures and 3C structures with defects along [111] direction. The distribution of the gas concentration in the reaction vessel and the growth mechanism of the SiC@SiO2 nanowires were studied. Furthermore, the SiC@SiO2 nanowires showed good blue-green photoluminescence (PL) property, which has been expected to make positive progress in the optoelectronic field.