Structural and Optical Characteristics of Crystalline Silicon Carbide Nanoparticles Synthesized by Carbothermal Reduction

Silicon carbide (SiC) nanoparticles were successfully synthesized by using carbothermal reduction method. Nanoparticles with zincblende structure (3C-SiC) could be prepared using polysiloxane as silicon source and phenol resin (MH) or xylene resin (YN) as carbon source. The sample YN has an average grain size of 22 nm, larger than that of the sample MH (8 nm). Raman spectroscopy revealed that all nanoparticle samples contain graphitic surface carbon layers. Oxygen contamination on the nanoparticle surface could be reduced by postfluorine treatment (MH-F). But the sample MH-F showed reduced SiC crystallinity compared with the sample MH. The nanoparticle samples exhibited an intensive emission band in the blue region observed by photoluminescence (PL) spectroscopy. The band-gap energy of the nanoparticle samples is estimated to be similar to 3 eV from the PL spectra, blueshifted by similar to 0.6 eV from that of bulk 3C-SiC due to the quantum confinement effect.