Warner Jamie H, Rümmeli Mark H, Ge Ling, Gemming Thomas, Montanari Barbara, Harrison Nicholas M, Büchner Bernd, Briggs G Andrew D
Department of Materials, Quantum Information Processing Interdisciplinary Research Collaboration, University of Oxford, Oxford, UK.
Nat Nanotechnol. 2009 Aug;4(8):500-4. doi: 10.1038/nnano.2009.194. Epub 2009 Aug 2.
Graphene has remarkable electronic properties, such as ballistic transport and quantum Hall effects, and has also been used as a support for samples in high-resolution transmission electron microscopy and as a transparent electrode in photovoltaic devices. There is now a demand for techniques that can manipulate the structural and physical properties of graphene, in conjunction with the facility to monitor the changes in situ with atomic precision. Here, we show that irradiation with an 80 kV electron beam can selectively remove monolayers in few-layer graphene sheets by means of electron-beam-induced sputtering. Aberration-corrected, low-voltage, high-resolution transmission electron microscopy with sub-ångström resolution is used to examine the structural reconstruction occurring at the single atomic level. We find preferential termination for graphene layers along the zigzag orientation for large hole sizes. The temporal resolution can also be reduced to 80 ms, enabling real-time observation of the reconstruction of carbon atoms during the sputtering process. We also report electron-beam-induced rapid displacement of monolayers, fast elastic distortions and flexible bending at the edges of graphene sheets. These results reveal how energy transfer from the electron beam to few-layer graphene sheets leads to unique structural transformations.
石墨烯具有卓越的电子特性，如弹道输运和量子霍尔效应，并且还被用作高分辨率透射电子显微镜中样品的支撑材料以及光伏器件中的透明电极。现在需要能够操控石墨烯的结构和物理性质的技术，同时具备以原子精度原位监测变化的能力。在此，我们表明用80 kV电子束辐照可通过电子束诱导溅射选择性地去除少层石墨烯片中的单层。利用具有亚埃分辨率的像差校正低电压高分辨率透射电子显微镜来检查在单原子水平上发生的结构重构。我们发现对于大尺寸孔洞，石墨烯层沿锯齿取向存在优先终止。时间分辨率也可降低至80毫秒，从而能够实时观察溅射过程中碳原子的重构。我们还报告了电子束诱导的单层快速位移、快速弹性畸变以及石墨烯片边缘的柔性弯曲。这些结果揭示了从电子束到少层石墨烯片的能量转移如何导致独特的结构转变。
