Evidence of hydrogen termination at grain boundaries in ultrananocrystalline diamond/hydrogenated amorphous carbon composite thin films synthesized via coaxial arc plasma
Evidence of hydrogen termination at grain boundaries in ultrananocrystalline diamond/hydrogenated amorphous carbon composite thin films synthesized via coaxial arc plasma
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通过同轴电弧等离子体合成的超纳米晶金刚石/氢化非晶碳复合薄膜中氢终止的证据
DOI：
10.1116/6.0000545
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
N. Nishikawa
中科院分区：
文献类型：
--
作者：
N. Nishikawa
超非晶金刚石/氢化非晶碳复合薄膜由三种不同的成分组成；超纳米晶金刚石微晶、氢化无定形碳以及它们之间的晶界。由于晶界含有大量悬空键和不饱和键，因此它们可能是载流子陷阱中心导致紫外光电探测器等可能应用中器件性能降低的原因。我们通过实验证明氢原子优先在晶界结合并通过几种光谱技术终止悬挂键。 XPS 测量无法检测薄膜中 sp^2 和 sp^3 杂化碳的定量转变，导致 sp^3 含量为 55-59%。另一方面，FT-IR 和 NEXAFS 确实表现出某些碳杂化量的一些变化。前者证实了通过额外加氢从 sp^2 到 sp^3 碳氢化合物的转变约 10%，后者代表了从 {\pi}* C{\equiv}C 和 {\pi}* C=C 到 {\sigma}* C-H 的化学构型变化。这些结果可以作为晶界处局域氢的证据，氢在终止悬挂键和不饱和键中发挥作用，并且它们与之前一些研究中研究的薄膜的光学和电学性质相关。我们对氢化效应的光谱研究结合对光学和电学特性的讨论证实，氢化可以成为增强上述传感应用中光伏性能的有效工具。
Ultranonocrystalline diamond/hydrogenated amorphous carbon composite thin films consist of three different components; ultrananocrystalline diamond crystallites, hydrogenated amorphous carbon, and grain boundaries between them. Since grain boundaries contain a lot of dangling bonds and unsaturated bonds, they would be a cause of carrier trap center degrading device performance in possible applications such as UV photo-detectors. We experimentally demonstrate hydrogen atoms preferentially incorporate at grain boundaries and terminate dangling bonds by means of several spectroscopic techniques. XPS measurements cannot detect quantitative transitions of sp^2- and sp^3-hybridized carbons in the films, resulting in 55-59 % of sp^3 contents. On the other hand, FT-IR and NEXAFS exhibit some variations of the amounts of certain carbon hybridization for sure. The former confirms the transformation from sp^2 to sp^3 hydrocarbons by ~10 % by additional hydrogenation, and the latter represents chemical configuration changes from {\pi}* C{\equiv}C and {\pi}* C=C to {\sigma}* C-H. These results can be an evidence of localized hydrogen at grain boundaries, which plays a part in terminating dangling bonds and unsaturated bonds, and they are correlated with the optical and electrical properties of the films investigated in some previous research. Our spectroscopic studies on the hydrogenation effects combined with the discussion on the optical and electrical characteristics confirm that the hydrogenation can be an effective tool of an enhancement of photovoltaic performance in the above sensing applications.
影响因子：
3.7
作者：
Ganguly, Abhijit;Sharma, Surbhi;Hamilton, Jeremy
通讯作者：
Hamilton, Jeremy