Temperature-controlled synthesis, thermodynamics and field emission properties of β-SiC/SiO2 coaxial heterojunction emitters

Abstract

β-SiC/SiO₂ coaxial heterogeneous emitters composed of a SiC nanowire core and a uniform amorphous SiO₂ coating have been fabricated via the chemical vapor deposition (CVD) technique. The effect of synthesis temperature on the yield, microstructure, and chemical composition of the products was systematically analysed. A rational explanation for the growth of the β-SiC/SiO₂ emitter was proposed and analysed from the perspective of the reaction thermodynamics. The field emission behaviors of the β-SiC/SiO₂ coaxial nanocables exhibit a strong dependence on the synthesis temperatures. Excellent performances with a low turn-on field (E_to) of 0.63 V μm⁻¹ and threshold field (E_th) of 1.92 V μm⁻¹ have been recorded at 1200 °C. Furthermore, the optimized cathode shows remarkable electron emission stability with the fluctuation of the current density being less than 5.7% after a 3 h long lifetime test.