Crystalline Silicon Carbide Nanoparticles Encapsulated in Branched Wavelike Carbon Nanotubes:Synthesis and Optical Properties

摘要

A novel nanostructure,cubic silicon carbide (3C-SiC) nanoparticles encapsulated in branched wavelike carbon nanotubes have been prepared by a reaction of 1,2-dimenthoxyethane (CH_3OCH_2CH_2OCH_3),SiCl_4,and Mg in an autoclave at 600degC.According to X-ray powder diffraction,the products are composed of 3C-SiC and carbon.TEM and HRTEM images show that the as-synthesized products are composed of 3C-SiC nanoparticles encapsulated in branched carbon nanotubes with wavelike walls.The diameter of the 3C-SiC cores is approximately 20-40 nm and the thickness of the carbon shells is about 3-5 nm.In Raman scattering spectroscopy,both the TO (GAMMA) phonon line and the LO (GAMMA) phonon line have red shifts about 6 cm~(-1) relative to that for the bulk 3C-SiC.The photoluminescence (PL) spectrum shows that there are two emission peaks:blue light emission (431 nm) and violet light emission (414 nm).A sequential deposition growth process (with cores as the templates for the shells) for the nanostructure was proposed.