Large-scale synthesis and photoluminescence properties of hexagonal-shaped SiC nanowires

Hexagonal-shaped SiC nanowires were synthesized by a simple thermal reaction method between ball-milled activated carbon and vaporized silicon at 1600 °C without catalyst assistant. Electron microscopy, X-ray diffraction, energy dispersive spectrum, Raman and photoluminescence spectra were employed to characterize the samples. Results show that the nanowires consist of crystalline core of β-SiC and little α-SiC with diameters of 50–200 nm wrapped with a thin amorphous silicon oxide shell. The range of the nanowires’ lengths is from several hundred nanometers to dozens of microns. The hexagonal-shaped SiC nanowires exhibit two strong broad photoluminescence peaks at wavelengths of about 289 and 391 nm, which are significantly shifted to the blue compared with the reported luminescence results of SiC nanowires/nanocables. The blueshifts may be ascribed to morphology and quantum size confinement effects of the nanomaterials and abundant structure defects existed in the nanowires.