Large-scale preparation of faceted Si3N4 nanorods from β-SiC nanowires

Batch-fabricated SiC nanowires were heated under an ammoniac flow up to 1400. C. The ensuing product was characterized by SEM, HRTEM, EDX and XRD. As we found, SiC nanowires were completely converted into faceted alpha- Si3N4 nanorods with diameters ranging from 10 to 500 nm and lengths lower than 10 mu m. These nanorods present hexagonal cross sections. We suggest a growth mechanism based on the progressive elimination of carbon through hydrogenation reactions and the growth of silicon nitride nanorods via the high-temperature nitridation of silicon.