Abstract With graphene as a well-known representative, two-dimensional (2D) atomic crystals are single-layer or few-layer crystalline materials. It is significant to investigate the structure evolution of the 2D atomic crystals in electronic movement process, because it relates to the stability of material properties and the feasibility of the device application. Here, the pinhole evolution of few-layer graphene during electron tunneling and electron transport was observed using in situ transmission electron microscopy (TEM). For few-layer graphene with defects, pinholes expanded with an increase on the electron tunneling current and time, respectively. However, during electron transport processes, with increasing current and time, both, expansion and shrinkage behaviors could be observed among the pinholes distributed within the graphene nanosheet. These behaviors are the result of competition between sublimation and self-repair. Both types of pinhole evolution aim to form a smooth surface with lower surface free energy. The critical boundary conditions for the sublimation and self-repair are determined by the temperature, graphene pinhole structure and active graphene fragment. These findings provide significant reference for the stability of graphene structure and the reliability of graphene based electronic device.

中文翻译：

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电子隧穿和电子传输过程中少层石墨烯的针孔演化

摘要 以石墨烯为代表的二维（2D）原子晶体是单层或少层晶体材料。研究电子运动过程中二维原子晶体的结构演化具有重要意义，因为它关系到材料性能的稳定性和器件应用的可行性。在这里，使用原位透射电子显微镜（TEM）观察了电子隧道和电子传输过程中少层石墨烯的针孔演变。对于具有缺陷的少层石墨烯，针孔分别随着电子隧道电流和时间的增加而扩大。然而，在电子传输过程中，随着电流和时间的增加，在分布在石墨烯纳米片内的针孔中可以观察到膨胀和收缩行为。这些行为是升华与自我修复竞争的结果。两种类型的针孔演化都旨在形成具有较低表面自由能的光滑表面。升华和自修复的临界边界条件由温度、石墨烯针孔结构和活性石墨烯碎片决定。这些发现为石墨烯结构的稳定性和基于石墨烯的电子器件的可靠性提供了重要参考。升华和自修复的临界边界条件由温度、石墨烯针孔结构和活性石墨烯碎片决定。这些发现为石墨烯结构的稳定性和基于石墨烯的电子器件的可靠性提供了重要参考。升华和自修复的临界边界条件由温度、石墨烯针孔结构和活性石墨烯碎片决定。这些发现为石墨烯结构的稳定性和基于石墨烯的电子器件的可靠性提供了重要参考。