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

beta-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 beta-SiC/SiO2 emitter was proposed and analysed from the perspective of the reaction thermodynamics. The field emission behaviors of the beta-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 mu m(-1) and threshold field (E-th) of 1.92 V mu m(-1) have been recorded at 1200 degrees 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.