Department of Materials, University of Oxford , Parks Rd, Oxford, OX1 3PH, United Kingdom.
Nano Lett. 2013 Oct 9;13(10):4937-44. doi: 10.1021/nl402902q. Epub 2013 Sep 10.
Ripples in graphene are an out-of-plane distortion that help stabilize suspended monolayer graphene. The introduction of disclinations and dislocations into the lattice of graphene is predicted to extensively ripple graphene to form "hillocks" to accommodate the strain in the system. Here, we confirm this theoretical prediction by intentionally introducing large numbers of dislocations into a predefined area of pristine monolayer graphene by scanning focused electron beam irradiation and imaging the rippled atomic lattice structure with aberration-corrected transmission electron microscopy. Hillocks are observed and analyzed using geometric phase analysis to determine heights of ~0.5 nm. Time-dependent imaging shows the rippling is dynamic under the electron beam and can fluctuate between different structural configurations. This demonstrates a means of perturbing the structure of graphene in all three spatial dimensions with nanoscale precision.
石墨烯中的波纹是一种面外变形，有助于稳定悬浮的单层石墨烯。理论预测，在石墨烯晶格中引入螺旋位错和位错会使石墨烯广泛地产生波纹，形成“小山丘”以适应系统中的应变。在这里，我们通过扫描聚焦电子束辐照在原始单层石墨烯的预定义区域中有意引入大量位错，并使用具有像差校正的透射电子显微镜对波纹原子晶格结构进行成像，证实了这一理论预测。通过几何相位分析观察和分析了小山丘，以确定约 0.5nm 的高度。时变成像显示，在电子束下的波纹是动态的，并且可以在不同的结构构型之间波动。这证明了一种以纳米级精度在所有三个空间维度上扰动石墨烯结构的方法。
