Substrate Dependent Ad-Atom Migration on Graphene and the Impact on Electron-Beam Sculpting Functional Nanopores.
Substrate Dependent Ad-Atom Migration on Graphene and the Impact on Electron-Beam Sculpting Functional Nanopores.
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DOI：
10.3390/s17051091
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发表时间：
2017-05-10
期刊：
影响因子：
--
通讯作者：
Kim MJ
中科院分区：
文献类型：
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作者：
Freedman KJ;Goyal G;Ahn CW;Kim MJ
多年来，使用原子级薄的石墨烯进行分子传感引起了极大的关注，在某些情况下，它可能会取代传统薄膜的使用。对于纳米孔传感，石墨烯必须悬浮在孔径上，以便在独立区域中形成单个孔。纳米孔通常使用紧密聚焦的电子束（e-beam）钻孔，直到获得所需的孔径。然而，石墨烯的电子束雕刻不仅取决于取代原子的能力，还取决于阻碍原子在石墨烯表面迁移的能力。使用来自热离子电子源的相对较低的电子束通量，C原子敲除率似乎与电子束/石墨烯界面处碳原子吸引和积累的速率相当（即，Rknockout ≈ Racumulation）。在这种独特的条件下工作可以研究碳原子迁移以及各种基材材料对石墨烯电子束雕刻的影响。我们还表明，这些信息对于制造功能性石墨烯纳米孔至关重要，该纳米孔用于研究具有增加的空间分辨率的 DNA，这归因于原子薄膜。
The use of atomically thin graphene for molecular sensing has attracted tremendous attention over the years and, in some instances, could displace the use of classical thin films. For nanopore sensing, graphene must be suspended over an aperture so that a single pore can be formed in the free-standing region. Nanopores are typically drilled using an electron beam (e-beam) which is tightly focused until a desired pore size is obtained. E-beam sculpting of graphene however is not just dependent on the ability to displace atoms but also the ability to hinder the migration of ad-atoms on the surface of graphene. Using relatively lower e-beam fluxes from a thermionic electron source, the C-atom knockout rate seems to be comparable to the rate of carbon ad-atom attraction and accumulation at the e-beam/graphene interface (i.e., Rknockout ≈ Raccumulation). Working at this unique regime has allowed the study of carbon ad-atom migration as well as the influence of various substrate materials on e-beam sculpting of graphene. We also show that this information was pivotal to fabricating functional graphene nanopores for studying DNA with increased spatial resolution which is attributed to atomically thin membranes.