Morphologies of co-depositing W layer formed during He plasma irradiation
Morphologies of co-depositing W layer formed during He plasma irradiation
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DOI：
10.1088/1741-4326/aad24e
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发表时间：
2018-10-01
期刊：
影响因子：
3.3
通讯作者：
Tanaka, Hirohiko
中科院分区：
文献类型：
--
作者：
Kajita, Shin;Kawaguchi, Shota;Tanaka, Hirohiko
将钨(W)样品暴露在氦(He)等离子体中，W粒子被析出。结果表明，表面形成了可见的大规模纤维状纳米结构(LFN)。在生长初期，LFN的高度随照射时间呈指数增长。这种生长速度与传统的W纳米结构(FUZZ)的生长速度完全不同，后者的厚度与时间的平方根成正比。LFNS的生长具有全球毫米尺度的方向性；其方向始终类似于从磁场顺时针方向旋转45-60度。当插入负偏压样品时，光谱测量的样品附近的等离子体流动显著增加，并且LFN的生长方向与等离子体流动的方向一致。此外，即使当He入射离子能量低于毛状物生长的阈值能量(20-30 eV)时，也可以形成高度多孔的纤维状纳米结构或花椰菜状结构。
Tungsten (W) samples were exposed to helium (He) plasmas with precipitation of W particles. It was shown that visible large-scale fiberform nanostructures (LFNs) were formed on the surface. The height of the LFN increased exponentially with the irradiation time in the initial phase of the growth. The growth rate was totally different from that of the conventional W nanostructure (fuzz) growth by He plasma irradiation, where the thickness increased in proportion to the square root of time. The LFNs growth had a directionality in a millimeter global scale; the direction was always similar to 45-60 degree rotated in clockwise direction from the magnetic field. The plasma flow measured spectroscopically near the sample was found to significantly increase when inserting a negatively biased sample, and the growth direction of the LFN was consistent with the direction of the plasma flow. Moreover, highly porous fiberform nanostructures or cauliflower-like structures comprised the deposition layer even when the He incident ion energy was lower than the threshold energy of fuzz growth (20-30 eV).