Prism-shaped SiC nanowhiskers

A novel nanostructured, prism-shaped beta-SiC nanowhiskers have been synthesized by a reaction of carbon black and Si at 1500 degrees C for 12h. 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 beta-SiC and the growth direction is along [111]. 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 P-SiC. (C) 2006 Elsevier B.V. All rights reserved.