实际功函数的变化对金属二次电子发射影响的研究

论文总字数：23085字

目 录

一.引言 1

1. 二次电子发射应用的发展趋势 1

2. 二次电子发射的研究现状 1

二.二次电子发射的理论基础和特征分析 2

1.二次电子的发射原理 2

2.特征函数分析 3

三.到达金属表面的内二次电子的能量分布 3

四.Ф_real对B(Ф_real，E_F)的影响 5

五.Ф_real对 ε_c(Ф_real，E_F) 的影响 6

六.Ф_real对L(Ф_real，E_F)_mean的影响 7

七.Ф_real 对 δ_m(Ф_real，E_F) 和 δ(Ф_real，E_F，E_p0) 的影响 8

八.结果与讨论 9

1.不同金属的二次电子表面能量分布分析 10

2.到达表面的二次电子逸出概率B(Ф_real，E_F)随Ф_real的变化分析 14

3.逸出所需平均能量ε_c(Ф_real，E_F)随着Ф_real的变化分析 12

4.内二次电子的能量占比随Ф_real 的变化分析 12

5.B(Ф_real，E_F)与 ε_c(Ф_real，E_F)随Ф_real 的变化比较 12

6.L(Ф_real，E_F)_mean随Фreal的变化分析 13

7.δ(Ф_real，E_F，E_p0)的结果分析 13

8.小结 14

九.结论 14

参考文献 16

致谢 16

附录 17

实际功函数的变化对金属二次电子发射影响的研究

刘浩宇

，China

Abstract：Different sample preparation can lead to different surface composition (contamination and oxidation) and different real work function Ф_real, and different sample preparation can lead to different parameters of secondary electron emission from the same kind of metal such as B(Ф_real, E_F), ε(Ф_real, E_F),λ(Ф_real, E_F) and δ_m(Ф_real, E_F); where E_F is the distance from Fermi energy to the bottom of the conduction band, B(Ф_real, E_F) is the probability that an internal secondary electrons reaching surface pass over the surface barrier into vacuum, ε(Ф_real, E_F) is the average energy required to produce an internal secondary electron excited from the conduction band and inner-shell,λ(Ф_real, E_F) is mean escape depth of secondary electrons, and δ_m(Ф_real, E_F) is the maximum secondary electron yield from metal. Based on free-electron model, the energy range of excited electrons and internal secondary electrons, the energy band of a metal, the existed formulae, the processes and characteristics of secondary electron emission, the formulae for the influence of changes of Ф_real on B(Ф_real, E_F), ε_c(Ф_real, E_F), L(Ф_real, E_F)_mean and δ_m(Ф_real, E_F) were deduced, respectively; where ε_c(Ф_real, E_F) and L(Ф_real,E_F)_mean are the average energy required to produce an internal secondary electron excited from the conduction band and inelastic mean escape depth of secondary electrons, respectively. The formula for the influence of changes of Ф_real on δ_m(Ф_real, E_F) was proved to be true, and the results were analyzed. It is concluded that the formula for the influence of changes of Ф_real on δ_m(Ф_real, E_F) can be used to estimate the influence of changes of Ф_real on δ(Ф_real, E_F, E_p0) and δ_m(Ф_real, E_F), and that the change of λ(Ф_real, E_F) with Ф_real has much more influence on the change of δ(Ф_real, E_F, E_p0) and δ_m(Ф_real, E_F) with Ф_real than the change of [B(Ф_real,E_F)/ ε(Ф_real, E_F)] with Ф_real does; where E_p0 and δ(Ф_real, E_F, E_p0) are incident energy of primary electron and secondary electron yield from metal at E_p0.

Key words：real work function; surface composition; secondary electron emission; secondary electron yield.

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