Catalytic synthesis and growth mechanism of SiC@SiO2 nanowires and their photoluminescence properties

SiC@SiO2 nanowires were synthesized on a Si substrate by thermal evaporation method with an iron nitrate catalyst. The as-grown nanowires were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy and photoluminescence spectroscopy at room temperature. Characterization indicated that the nanowires were composed of a crystalline SiC core with a thin amorphous SiO2 shell. The typical SiC core diameter was 50-100 nm, whereas the SiO2 shell thickness was 5-10 nm and they had a length of several hundreds of micrometers. A combined vapor-liquid-solid (VLS) base-growth and vapor-solid (VS) tip-growth mechanism is proposed for the growth mode of the as-grown SiC@SiO2 nanowires. The intensive blue-green emission properties of the core-shell SiC-SiO2 nanowires are of significant interest for their potential blue-green emitting device applications.