A metal-free route to synthesize pure-phase 3C-SiC with excellent optical and magnetic properties

Large amount of pure-phase 3C-SiC particles were synthesized via microwave heating, without using any metal catalyst. Ball-milling pre-treatment was employed to enhance reaction activity of raw materials prior to the microwave heating process. The morphology, microstructure of the SiC products were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and transmission electron microscope (TEM). As the result of SEM, the SiC particles have diameters of 500–2000 nm and smooth surface. TEM image shows that some of the micro-sized SiC particles are composed of agglomerate nano-particles with diameters of 50–200 nm. Photoluminescence and magnetic properties of the SiC products were measured by fluorescence spectrophotometer and vibrating sample magnetometer (VSM), respectively. Ultra-violet emission from the 3C-SiC products can be detected under excitation wavelength of 240 nm. Without any contribution from the magnetic metal ions, the SiC particles can exhibit ferromagnetic properties around room temperature with saturation magnetization (Ms) of 0.9 emu/g, approximately. The excellent optical and magnetic properties of SiC may mainly be attributed to the point defects.