Synthesis and characterization of 3C and 2H-SiC nanocrystals starting from SiO2, C2H5OH and metallic Mg

Silicon carbide (3C-SiC) nanocrystals were prepared starting from SiO2, C2H5OH, and metallic Mg in an autoclave at 200 deg. C. X-ray diffraction patterns of the sample can be indexed as the cubic phase of SiC with the lattice constant a = 4.357 A, in good agreement with the reported value (JCPDS card no. 29-1129; a = 4.359 A). Transmission electron microscopy images show that the product mainly composed of nanowires with diameters in the range of 10-30 nm and lengths up to tens of micrometers; High-resolution transmission electron microscopy images reveal that these 3C-SiC nanowires grow along [1 1 1] direction; As polyvinylpyrrolidine was added into the above reactant system, the final products obtained at 180 deg. C were mixed 3C and 2H-SiC flakes. Thermal gravimetric analysis curves reveal that these two samples have thermal stability below 800 deg. C, and room-temperature photoluminescence spectrum of the 3C-SiC sample show a strong emission peak centered at 403 nm.