Crystalline silicon carbide nanoparticles encapsulated in branched wavelike carbon nanotubes: Synthesis and optical properties

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 (CH₃OCH₂CH ₂OCH₃), SiCl₄, and Mg in an autoclave at 600°C. 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 (Γ) phonon line and the LO (Γ) 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.