Bocharov Grigory S, Eletskii Alexander V
Moscow Power Engineering Institute, Technical University, Krasnokazarmennaya 14, Moscow 111250, Russia.
National Research Center, Kurchatov Institute, Kurchatov sq. 1, Moscow 123182, Russia.
Nanomaterials (Basel). 2013 Jul 17;3(3):393-442. doi: 10.3390/nano3030393.
Theoretical problems arising in connection with development and operation of electron field emitters on the basis of carbon nanotubes are reviewed. The physical aspects of electron field emission that underlie the unique emission properties of carbon nanotubes (CNTs) are considered. Physical effects and phenomena affecting the emission characteristics of CNT cathodes are analyzed. Effects given particular attention include: the electric field amplification near a CNT tip with taking into account the shape of the tip, the deviation from the vertical orientation of nanotubes and electrical field-induced alignment of those; electric field screening by neighboring nanotubes; statistical spread of the parameters of the individual CNTs comprising the cathode; the thermal effects resulting in degradation of nanotubes during emission. Simultaneous consideration of the above-listed effects permitted the development of the optimization procedure for CNT array in terms of the maximum reachable emission current density. In accordance with this procedure, the optimum inter-tube distance in the array depends on the region of the external voltage applied. The phenomenon of self-misalignment of nanotubes in an array has been predicted and analyzed in terms of the recent experiments performed. A mechanism of degradation of CNT-based electron field emitters has been analyzed consisting of the bombardment of the emitters by ions formed as a result of electron impact ionization of the residual gas molecules.
综述了基于碳纳米管的电子场发射体开发与运行中出现的理论问题。考虑了作为碳纳米管（CNT）独特发射特性基础的电子场发射的物理方面。分析了影响CNT阴极发射特性的物理效应和现象。特别关注的效应包括：考虑到尖端形状时CNT尖端附近的电场放大、纳米管偏离垂直取向以及电场诱导的纳米管排列；相邻纳米管的电场屏蔽；构成阴极的单个CNT参数的统计分布；发射过程中导致纳米管退化的热效应。同时考虑上述效应使得能够根据最大可达发射电流密度制定CNT阵列的优化程序。根据该程序，阵列中最佳的管间距取决于所施加外部电压的范围。根据最近进行的实验预测并分析了阵列中纳米管的自失准现象。分析了基于CNT的电子场发射体的退化机制，该机制包括残余气体分子因电子碰撞电离而形成的离子对发射体的轰击。
