Development of TEM and SEM high brightness electron guns using cold-field emission from a carbon nanotip
Development of TEM and SEM high brightness electron guns using cold-field emission from a carbon nanotip
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DOI：
10.1016/j.ultramic.2014.11.021
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发表时间：
2015-04-01
期刊：
影响因子：
2.2
通讯作者：
Snoeck, E.
中科院分区：
文献类型：
--
作者：
Houdellier, F.;de Knoop, L.;Snoeck, E.
一种新研制的碳锥纳米尖（CCNT）作为场发射阴极，在低压SEM（30 kV）和高压TEM（200 kV）电子源中均得到了应用。结果清楚地表明，对于这两种技术，发射和探针电流的前所未有的稳定性，在1小时内几乎没有衰减，以及与使用钨尖端作为发射阴极的标准源相比，噪声非常小（均方根小于0.5%）。此外，定量电场映射周围的FE尖端已进行使用原位电子全息实验期间的新尖端的发射。这些结果显示了新的CCnT的非常高的纵横比的优点，其引起在尖端的顶点处保持的电的强烈增强，从而导致将开始场发射的非常小的提取电压（几百伏）。这些实验与发射电流测量的组合也允许提取4.8 eV的出口功函数值。(C)2014爱思唯尔有限公司版权所有。
A newly developed carbon cone nanotip (CCnT) has been used as field emission cathode both in low voltage SEM (30 kV) electron source and high voltage TEM (200 kV) electron source. The results clearly show, for both technologies, an unprecedented stability of the emission and the probe current with almost no decay during 1 h, as well as a very small noise (rms less than 0.5%) compared to standard sources which use tungsten tips as emitting cathode. In addition, quantitative electric field mapping around the FE tip have been performed using in situ electron holography experiments during the emission of the new tip. These results show the advantage of the very high aspect ratio of the new CCnT which induces a strong enhancement of the electric held at the apex of the tip, leading to very small extraction voltage (some hundred of volts) for which the field emission will start. The combination of these experiments with emission current measurements has also allowed to extract an exit work function value of 4.8 eV. (C) 2014 Elsevier B.V. All rights reserved.