Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Research &Innovation Center, National Energy Technology Laboratory, U.S. Department of Energy, Pittsburgh, Pennsylvania 15236, USA.
Nat Commun. 2016 Oct 31;7:13263. doi: 10.1038/ncomms13263.
The interest in mechanical properties of two-dimensional materials has emerged in light of new device concepts taking advantage of flexing, adhesion and friction. Here we demonstrate an effective method to measure adhesion of graphene atop highly ordered pyrolytic graphite, utilizing atomic-scale 'blisters' created in the top layer by neon atom intercalates. Detailed analysis of scanning tunnelling microscopy images is used to reconstruct atomic positions and the strain map within the deformed graphene layer, and demonstrate the tip-induced subsurface translation of neon atoms. We invoke an analytical model, originally devised for graphene macroscopic deformations, to determine the graphite adhesion energy of 0.221±0.011 J m. This value is in excellent agreement with reported macroscopic values and our atomistic simulations. This implies mechanical properties of graphene scale down to a few-nanometre length. The simplicity of our method provides a unique opportunity to investigate the local variability of nanomechanical properties in layered materials.
人们对二维材料力学性能的兴趣源于新的器件概念，这些概念利用了弯曲、粘附和摩擦等特性。在这里，我们展示了一种利用氖原子嵌入顶层形成原子级“气泡”来测量石墨烯与高度有序热解石墨之间粘附力的有效方法。通过对扫描隧道显微镜图像的详细分析，我们重构了变形石墨烯层内的原子位置和应变图，并证明了尖端诱导氖原子在亚表面的平移。我们引入了一个分析模型，该模型最初是为石墨烯的宏观变形设计的，用于确定石墨的粘附能为 0.221±0.011 J m。该值与报道的宏观值和我们的原子模拟非常吻合。这意味着石墨烯的力学性能可以扩展到几个纳米的长度。我们方法的简单性为研究层状材料中纳米力学性能的局部变化提供了一个独特的机会。
