Direct growth of core-shell SiC-SiO(2) nanowires and field emission characteristics.

A simple, direct synthesis method was used to grow core-shell SiC-SiO(2) nanowires by heating NiO-catalysed silicon substrates. A carbothermal reduction of WO(3) provided a reductive environment and carbon source to synthesize crystalline SiC nanowires covered with SiO(2) sheaths at the growth temperature of 1000-1100 °C. Transmission electron microscopy showed that the SiC core was 15-25 nm in diameter and the SiO(2) shell layer was an average of 20 nm in thickness. The thickness of the SiO(2) shell layer could be controlled using hydrofluoric acid (HF) etching. Field emission results of core-shell SiC-SiO(2) and bare SiC nanowires showed that the SiC nanowires coated with an optimum SiO(2) thickness (10 nm) have a higher field emission current than the bare SiC nanowires.