摘要
单晶LaB_6尖锥有望成为理想的场致电子发射阴极,采用三维粒子模拟软件Computer Simulation Technology(CST)对尖锥曲率半径在0.1~10μm范围内的系列单晶LaB_6尖锥阴极的场致发射特性进行了模拟。研究结果表明,单晶LaB_6尖锥的电子发射轨迹为倒立锥形,锥尖处电位线最密集且场强最大,且随锥尖曲率半径的减小,锥尖处场强增大,发射电流增大。当LaB_6尖锥的锥角40°,锥高Ht=2 mm,锥尖曲率半径Rt=0.1μm时,尖锥获得最佳场发射性能:电场强度E=7.22×107V/cm,发射电流I=25.5μA。为具有优良场发射性能的单晶LaB_6尖锥场发射阴极的几何结构设计和加工提供了理论指导。
The field emission of single crystalline LaB_6 tip was mathematically modeled with atruncated cone capped with a hemisphere,theoretically analyzed in Fowler-Nordheim equation,and numerically simulated with CST software. The impact of the cone-angle and spherical radius of the LaB_6 tipon the field emission behavior was investigated. The simulated results show that the tip radius significantly affects the field emission behavior. For example,as the tip radius decreases,the field emission current increased,simply because of the intensifying emission field.The conical-shaped emission electron beam spreads out from the tip apex. With a cone angle of40°,a height of 2 mm and a hemisphere radius of 0. 1 μm,the optimized total emission current was 25. 5 μA ata field of 7. 22 × 107 V/cm.We suggest that the simulated results may be of some technological interest in application of LaB_6 emitter.
出处
《真空科学与技术学报》
EI
CAS
CSCD
北大核心
2018年第2期140-143,共4页
Chinese Journal of Vacuum Science and Technology
基金
国家自然科学基金项目(51371010)
北京市教育委员会科技计划面上项目(KM201510005001)
关键词
单晶六硼化镧
场致发射
尖锥
CST
Single crystal Lanthanum hexaboride, Field emission, Tip, CST
