Graphene-based SiC nanowires with nanosheets: synthesis, growth mechanism and photoluminescence properties

3C-SiC nanowires with nanosheets were synthesized via direct reaction of Si vapor (from solid silicon) and SiO vapor (from silicon and silicon dioxide) with graphene nanosheets at 1500 °C without any additional metal catalyst. The resultant products were characterized by XRD, SEM, TEM and room-temperature photoluminescence (PL) spectroscopy. The results indicated that the product comprised SiC nanowires with nanosheets. The nanowires were mainly consists of curvy aggregated wires with diameters of 30-80 nm, some representative straight whiskers with a pellet at their tips, as well as some distinctive structures including connected particles, dumbbell shape with dense stacking faults and periodical twins with screw dislocation. The nanosheets presented in the products were thin SiC polycrystalline multilayers within a few nanowires. A combined VLS and VS mechanisms were proposed for their formation. The PL spectra of the resultant SiC nanowires with nanosheets indicated a remarkable blue shift in comparison to its bulk SiC, implying them having great potential applications in optoelectronic devices.