Effects of fibre-form nanostructures on particle emissions from a tungsten surface in plasmas
Effects of fibre-form nanostructures on particle emissions from a tungsten surface in plasmas
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DOI：
10.1088/0029-5515/52/12/123001
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发表时间：
2012-10
期刊：
影响因子：
3.3
通讯作者：
S. Takamura;T. Miyamoto;N. Ohno
中科院分区：
文献类型：
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作者：
S. Takamura;T. Miyamoto;N. Ohno
钨表面纤维状纳米结构对氦/氩等离子体中电子发射和溅射的影响。一般来说，一个纳米纤维森林，所谓的“模糊”，由钨与氦气内被发现有抑制粒子排放的趋势。电子发射来自高能初级电子的撞击。此外，深偏置钨靶，它抑制即使是高能量的初级电子的流入，似乎产生电子发射，它可能会被抑制的方式上的纳米结构的形成在W靶的表面上。这里讨论这样的发射过程。具有纤维状纳米结构的He损伤的钨表面的溅射产额取决于表面形貌，而溅射本身改变表面形貌，因此发现具有原始发育良好的纳米结构的W表面的溅射产额的时间演变显示出溅射产额的最小值，这对于新鲜的纳米结构钨来说大约是一半，而对于原始的平坦的正常钨表面来说大约是五分之一。用场发射扫描电子显微镜观察，首次明确了当时的表面形貌。讨论了溅射产额出现极小值的物理机制。
The effects of fibre-form nanostructure of a tungsten surface on both electron emission and sputtering in helium/argon plasmas are represented. Generally, a nano-fibre forest, the so-called ‘fuzz’, made of tungsten with helium gas inside is found to have the tendency of suppressing the particle emission substantially. The electron emission comes from the impact of high-energy primary electrons. In addition, a deeply biased tungsten target, which inhibits the influx of even energetic primary electrons, seems to produce an electron emission, and it may be suppressed on the way to nanostructure formation on the surface of the W target. Such an emission process is discussed here. The sputtering yield of the He-damaged tungsten surface with the fibre-form nanostructure depends on the surface morphology while the sputtering itself changes the surface morphology, so that the time evolutions of sputtering yield from the W surface with an originally well-developed nanostructure are found to show a minimum in sputtering yield, which is about a half for the fresh nanostructured tungsten and roughly one-fifth of the yield for the original flat normal tungsten surface. The surface morphology at that time is, for the first time, made clear with field emission scanning electron microscopy observation. The physical mechanism for the appearance of such a minimum in sputtering yield is discussed.