In-situ Visualization of Local Field Enhancement in an Ultra Sharp Tungsten Emitter under a Low Voltage Scanning Transmission Electron Microscope
In-situ Visualization of Local Field Enhancement in an Ultra Sharp Tungsten Emitter under a Low Voltage Scanning Transmission Electron Microscope
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DOI：
10.1143/jjap.46.l498
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发表时间：
2007-05
影响因子：
1.5
通讯作者：
J. Fujita;Y. Ikeda;S. Okada;Kodai Higashi;S. Nakazawa;M. Ishida;S. Matsui
中科院分区：
文献类型：
--
作者：
J. Fujita;Y. Ikeda;S. Okada;Kodai Higashi;S. Nakazawa;M. Ishida;S. Matsui
我们发现，多壁碳纳米管的场发射通过焦耳加热软化了钨的底部，库仑对从钨尖端拉出的纳米管华丽的吸引导致了钨探针的超尖尖端的曲率半径为5 nm。我们还发现，在低加速电压下，可以用扫描电子显微镜(STEM)观察到探针尖端的局部增强场。在STEM图像中，初级电子被探测器的局部磁场偏转，并在探测器尖端周围形成了一个黑暗的阴影。简单的卢瑟福散射模型可以用来分析尖端的局部电场。
We found that field emissions from a multi-walled carbon nanotube soften the bottom of the tungsten by Joule heating, and the coulomb attraction to the nanotube finery pulled off from the tungsten tip resulted in an ultra sharp apex of the tungsten probe having 5 nm in radius of curvature. We also found that a locally enhanced field at the probe apex can be visualized using scanning transmission electron microscopy (STEM) under low accelerating voltage operation. The primary electrons were deflected by the local field out of the detector and created a dark shadow surrounding the probe apex in the STEM image. Simple Rutherford scattering model could be adopted to analyze the local electric field at the tip apex.