Thirty per cent contrast in secondary-electron imaging by scanning field-emission microscopy
Thirty per cent contrast in secondary-electron imaging by scanning field-emission microscopy
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扫描场发射显微镜二次电子成像对比度达 30%
DOI：
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发表时间：
2016
期刊：
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通讯作者：
U. Ramsperger
中科院分区：
文献类型：
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作者：
D. A. Zanin;L. G. D. Pietro;Quentin Peter;A. Kostanyan;H. Cabrera;Alessandro Vindigni;T. Bähler;D. Pescia;U. Ramsperger
我们进行扫描隧道显微镜（STM）在一个制度，其中初级电子是场发射的尖端和激发二次电子的目标-扫描场发射显微镜制度（SFM）。在SFM模式下，当对干净的W（110）-和Fe-覆盖的W（110）-平台之间的单原子台阶成像时，观察到高达30%的二次电子对比度。这是一个与STM相当的对比图。单原子台阶的表观宽度达到1 nm标记，即它仅比STM中观察到的相应宽度略差。SFM中意想不到的强对比度的起源是二次电子产率的材料依赖性，而不是传输电流对尖端-目标距离的依赖性，这是STM的典型特征：因此，我们预计STM和SFM相结合的技术将突出表面的互补方面，同时使以纳米空间精度选择的电子可用于宏观环境进行进一步处理。
We perform scanning tunnelling microscopy (STM) in a regime where primary electrons are field-emitted from the tip and excite secondary electrons out of the target—the scanning field-emission microscopy regime (SFM). In the SFM mode, a secondary-electron contrast as high as 30% is observed when imaging a monoatomic step between a clean W(110)- and an Fe-covered W(110)-terrace. This is a figure of contrast comparable to STM. The apparent width of the monoatomic step attains the 1 nm mark, i.e. it is only marginally worse than the corresponding width observed in STM. The origin of the unexpected strong contrast in SFM is the material dependence of the secondary-electron yield and not the dependence of the transported current on the tip–target distance, typical of STM: accordingly, we expect that a technology combining STM and SFM will highlight complementary aspects of a surface while simultaneously making electrons, selected with nanometre spatial precision, available to a macroscopic environment for further processing.