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从实验和理论上研究单根碳纳米管(CNT)场发射电子源的稳定问题。利用透射电镜/扫描探针显微镜(TEM/SPM)和场发射显微镜/场离子显微镜(FEM/F IM)对CNT s的场发射特性进行了实验研究。同时从密度泛函理论出发,利用相关程序模拟计算了吸附对单壁碳纳米管(SW NT s)场发射的影响。发现SW NT s荷电体系的总能量与荷电电荷数量关系具有抛物线形式,先减小,达到最小值,之后增加。通常荷4个电子时达到最小值,即体系处于最稳定状态。表明SW NT s有很大的电负性,是容易发生凝聚和吸附分子的根源。进而计算了对氢、氧和水的吸附特性,讨论了吸附对场发射的影响。这些结果对CNT s的场发射特性和作为新型电子源的应用都是有重要意义的。
The stability of single-walled carbon nanotube (CNT) field emission electron source is studied experimentally and theoretically. The field emission characteristics of CNTs were investigated by TEM / SPM and field emission microscopy / field emission microscopy (FEM / FIM). At the same time, based on the density functional theory, the influence of adsorption on the field emission of single-walled carbon nanotubes (SWNTs) was simulated by the relevant programs. It is found that the relationship between the total energy and the number of charged charges in SWNTs charge system has a parabolic shape, decreases first, reaches a minimum value, and then increases. Usually charge 4 electrons to reach the minimum, that is, the system is in the most stable state. Show that SWNTs have a great electronegativity, is prone to condensation and adsorption of molecules. Furthermore, the adsorption properties of hydrogen, oxygen and water were calculated and the influence of adsorption on field emission was discussed. These results are of great significance for the field emission properties of CNTs and their application as novel electron sources.