锥形与金字塔形场发射尖端电学特性分析

场致电子发射具有高效、响应快等优点，有着广泛的应用前景。锥形和金字塔形尖端是两种常见的场发射尖端结构。主要分析了这两种尖端结构的场发射电学特性，并在此基础上提出了进一步实现结构优化的途径。为此，建立了两种尖端的三维模型，并利用有限元法深入讨论了结构尺寸，包括尖端曲率半径、尖端与阳极间距以及尖端高度对电场分布以及电场强度的影响。结果表明，减小尖端曲率半径、缩短尖端与阳极间距、以及选择适当的锥体高度是优化尖端场致电子发射性能的三个重要途径。在综合考虑电场分布以及电场强度的情况下，可以发现锥形尖端更有利于产生高密度小束径的低能电子束，而金字塔形尖端则更适用于高压力灵敏度的应用需求。

Simulation studies on electrical characteristics of conical and pyramidal field emitters

Conical and pyramidal emitters are two generic field-emitter structures. Due to specific advantages of field emission, both emitters are widely employed to produce electron beams. The main focus of this paper is to analyze the electrical characteristics of both emitters, and further, to highlight the key criteria in optimizing the structures. For this purpose, three-dimensional models were implemented and finite-element analysis was used to investigate the influences of emitter geometries, including shape of emitter, emitter radius of curvature, emitter-anode distance and emitter height, on its electric field distribution and strength. The results indicate that reducing tip radius of curvature and shorting the emitter-anode distance are effective ways to increase the field strength enhancement, while a proper ratio of the emitter height to the emitter-anode distance is also an important factor. In addition, in consideration of both electric field distribution and strength, the conical emitter is suitable for high-resolution, large current-density applications, whereas the pyramidal emitter has better pressure sensitivity.