Direct growth of core-shell SiC-SiO2 nanowires and field emission characteristics

Abstract

A simple, direct synthesis method was used to grow core-shell SiC-SiO2 nanowires by heating NiO-catalysed silicon substrates. A carbothermal reduction of WO3 provided a reductive environment and carbon source to synthesize crystalline SiC nanowires covered with SiO2 sheaths at the growth temperature of 1000-1100 degrees C. Transmission electron microscopy showed that the SiC core was 15-25 nm in diameter and the SiO2 shell layer was an average of 20 nm in thickness. The thickness of the SiO2 shell layer could be controlled using hydrofluoric acid (HF) etching. Field emission results of core-shell SiC-SiO2 and bare SiC nanowires showed that the SiC nanowires coated with an optimum SiO2 thickness (10 nm) have a higher field emission current than the bare SiC nanowires.