Field emission tip effect and field emission performance of micro‐tip arrays fabricated on single‐crystal LaB6

Abstract A finite element simulation study is conducted using COMSOL Multiphysics software for tip effects such as induced potential, induced electric field intensity, and charge density of micro‐tips in a micro‐tips array under applied voltage. The simulation results indicate that under a constant micro‐tip spacing x , the field shielding effect increases as the micro‐tip curvature radius decreases. Moreover, when the tip spacing x is greater than twice the tip height h , the field shielding effect can be neglected. Based on the COMSOL simulation results of the micro‐tips array, the femtosecond laser processing technology was employed to achieve controllable fabrication of micro‐tips array microstructures on the (100) crystal plane of single‐crystal LaB 6 . Under the condition of good geometric morphology of the tips, tips with a height of 10 µm and a minimum tip curvature radius of 0.2 µm could be processed, with good uniformity in array morphology and distribution. Field emission performance tests show that under testing conditions with a vacuum level of 1 × 10 −5 Pa and an applied electric field E a of 5.6 V/µm, it exhibits a low turn‐on electric field E t (2.7 V/µm), a field emission current density of 4.36 A/cm 2 , and good emission stability.