Large-scale synthesis and photoluminescence properties of aligned multicore SiC-SiO2 nanocables

By using a simple and low-cost microwave method, aligned multicore SiC-SiO2 nanocables have been successfully synthesized on a large scale. The composition and structural features of the products were characterized by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results revealed that each of the nanocables was composed of several 3C-SiC nanowires encapsulated in a single amorphous SiO2 shell. The cores were 10-50 nm in diameter and up to hundreds of microns in length. The photoluminescence properties of the nanocables were studied, and strong violet blue light emission was observed at wavelengths of about 339 and 390 nm under 325-nm excitation. The origin of the photoluminescence from the nanocables can be attributed to the central SiC nanowires and defects in silicon oxide or the SiC/SiO2 interface boundary. Based on experimental characterizations, an oxide-assisted vapor-liquid-solid (VLS) growth mechanism was used to elucidate the growth process of the multicore SiC-SiO2 nanocables.