Al-Doped SiC nanowires wrapped by the nanowire network: excellent field emission property and robust stability at high current density

Abstract

Al-Doped SiC nanowires wrapped by the nanowire network were synthesized by a simple one-step calcination method. The characterization results showed that the nanowire network, which wrapped Al-doped SiC nanowires, was constructed of superficial Al-doped SiC nanowires and SiO₂ particles grown on the nanowire intersections. The synergistic effect of Al doping and the unique morphology endowed the as-constructed products with a lower turn-on field of 0.45 V μm⁻¹ and threshold field of 2.8 V μm⁻¹ as well as robust current emission stability. The simulation results from first principles proved that the band gap of SiC was narrowed after Al doping, which was more favorable for electron transmission from the valence band to the conduction band. More importantly, at a high current density of 10 mA cm⁻², the emission current fluctuation was less than 2.3% over 600 min. The stability measured at high current density was ascribed to the protection of the superficial nanowire network. This work will provide a new insight into the fabrication of field emission cathode materials with both low turn-on and threshold fields and robust current emission stability at high current density.