Control mechanism of the back insulated-gate in vacuum nano-electronics

Recently, with the advancement of micronanoscale manufacturing technologies, vacuum electronic devices, which are immune to harsh environments (e.g., high temperatures, severe radiation), have once again entered researchers’ horizons. There have been a lot of reports focused on the impacts of emitter materials and overall consideration of structures on device performances. However, there is less discussion on the influence of the gate with different configuration geometries, even which is an extremely important component in the designed device structure, playing a switching role. In this paper, we discuss the effects of the back insulated-gate structure with different configuration geometries on emission and collection currents. The results show that the emitter emits more electrons when the gate width is larger (i.e., the coupling effect between the gate and the emitter is better), which, in turn, is able to help the collector receive more electrons. The gate has a greater influence than the collector on the local electric field near the emitter, explaining that the gate plays a switching role in such vacuum channel transistors. Moreover, we find that increased gate voltage causes the emitted electron beam to be more dispersed. Different collector voltages lead to different trends in the collection efficiency curve. The effects of widths (in the direction perpendicular to current flow) of the collector and the emitter on the emission and collection currents are also discussed. These studies provide theoretical bases for the future device designing.