作　　者： ; ;

机构地区： 电子科技大学物理电子学院高能电子学研究所

出　　处： 《真空科学与技术》 1999年第3期201-206,共6页

摘　　要： 实际场致发射体表面不可能绝对光滑 ,而具有原子尺度的微小凸起会导致发射电流大大增加。基于发射电流主要来自于原子尺度微小凸起的假设 ,提出了局域半球镜像电荷模型 ,研究了场致发射功函数的降低 ,发现微小凸起处场致发射的局域功函数会降低而场增强因子将增大。将它代入F N公式计算了一个典型的单尖Spindt阴极的发射电流 ,所得结果与实验符合。在只考虑Nottingham效应的情况下 。 Protruding atoms or clusters on fairly smooth emitter surfaces play a dominant role in field emission,which may well account for the discrepancy that the calculated results are always much smaller than the experimental results.On atomic scale,there exist quite a few protruding atoms on any realistic field emitter surface.Taking into consideration of these protruding atoms,a new local hemisphere image charge model was proposed to understand the discrepancy.The preliminary results show that the protruding atoms leads to a considerable decrease of the local work function and a significant increase of the local electric field.The emission current of a typical Mo Spindt cathode was evaluated based on this model,and the calculated current agrees well with the experimental results.

关 键 词： 场致发射体 功函数 阴极电子学 公式

领　　域： [理学] [理学]