Prism-shaped SiC nanowhiskers

A novel nanostructured, prism-shaped β-SiC nanowhiskers have been synthesized by a reaction of carbon black and Si at 1500 deg. C for 12 h. Various durations of heating gave different growth stages that led to varied product morphologies. X-ray powder diffraction (XRD), field emission scanning electron microscope (FESEM) and high resolution transmission electron microscope (HRTEM) were used to characterize the products. These characterizations indicated that prism-shaped SiC nanowhiskers with a diameter of about 80-200 nm and the length up to several micrometers are straight, single crystalline β-SiC and the growth direction is along [1 1 1]. The results also show that the nucleation and growth process of the nanowhiskers seem to be a vapor-solid mechanism, and that the total heating time during the reaction process is a critical factor for the formation of prism-shaped SiC nanowhiskers. Some unique optical properties are found in the Raman spectroscopy that has red shift about 8 cm-1 relative to the bulk β-SiC