Aluminum-Doped Bamboo-like Silicon Carbide Nanowire Arrays with Ultrastable Field Emission

Field emission (FE) cathodes have shown considerable potential for utilization in vacuum electronic devices. In the field of cathode materials, silicon carbide (SiC) has garnered significant attention due to its exceptional properties. To enhance the FE performance of SiC field emitters, where the turn-on field (E_to) and emission current stability are critical performance parameters, the fabrication of SiC nanowires with sharp tip structures and elemental doping are effective strategies. In this study, the Al-doped bamboo-like SiC nanowire array field emitter was fabricated by a two-step process involving electrochemical etching followed by ex-situ doping. The SiC nanowires fabricated by electrochemical etching exhibit sharp tip structures and well-aligned arrangements, which are favorable for electron emission. In addition, ex-situ Al doping effectively reduces the bandgap of SiC and increases the density of localized states, thereby further enhancing its electron emission performance. The synergistic effects of the sharp bamboo-like morphology, highly ordered array, and Al doping result in a low E_to of 0.34 V/μm. Moreover, the emitter demonstrates exceptional emission stability, with only 1.3% current fluctuation over 12 h of continuous operation. Overall, its performance merit surpasses that of previously reported SiC emitters. This work presents a viable strategy for designing field emitters that simultaneously achieve a low turn-on field and high emission stability.