In-situ electrical conductance measurement of suspended ultra-narrow graphene nanoribbons observed via transmission electron microscopy
In-situ electrical conductance measurement of suspended ultra-narrow graphene nanoribbons observed via transmission electron microscopy
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DOI：
10.1088/1361-6528/abbca7
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发表时间：
2020-09
期刊：
影响因子：
3.5
通讯作者：
Chunmeng Liu;Jiaqi Zhang;Xiaobin Zhang;M. Muruganathan;H. Mizuta;Y. Oshima
中科院分区：
文献类型：
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作者：
Chunmeng Liu;Jiaqi Zhang;Xiaobin Zhang;M. Muruganathan;H. Mizuta;Y. Oshima
石墨烯纳米粒子是一种很有吸引力的纳米电子器件材料，因为它们的电输运性能可以通过它们的边缘结构来控制。然而，在大多数情况下，电输运已被研究仅为石墨烯纳米带制造在衬底上，这阻碍了本征电输运由于屏蔽效应的外观。在这项研究中，我们开发了基于硅芯片的透射电子显微镜的特殊设备，以观察悬浮在两个金电极之间的单层石墨烯纳米粒子。此外，随着原位透射电子显微镜保持器的发展，在观察和修改结构的同时实现了电流-电压特性。我们发现，1.5 nm宽的石墨烯纳米带扶手椅和锯齿形边缘结构之间的电流-电压特性不同。锯齿形边缘的能隙比扶手椅形边缘的能隙大两倍以上，并且在微分电导曲线中在临界偏压以上表现出突变。因此，我们的原位透射电子显微镜的方法是有前途的阐明二维材料中的导电结构的依赖性。
Graphene nanoribbon is an attractive material for nano-electronic devices, as their electrical transport performance can be controlled by their edge structures. However, in most cases, the electrical transport has been investigated only for graphene nanoribbons fabricated on a substrate, which hinders the appearance of intrinsic electrical transport due to screening effects. In this study, we developed special devices based on silicon chips for transmission electron microscopy to observe a monolayer graphene nanoribbon suspended between two gold electrodes. Moreover, with the development of an in-situ transmission electron microscopy holder, the current–voltage characteristics were achieved simultaneously with observing and modifying the structure. We found that the current–voltage characteristics differed between 1.5 nm-wide graphene nanoribbons with armchair and zigzag edge structures. The energy gap of the zigzag edge was more than two-fold larger than that of the armchair edge and exhibited an abrupt jump above a critical bias voltage in the differential conductance curve. Thus, our in-situ transmission electron microscopy method is promising for elucidating the structural dependence of electrical conduction in two-dimensional materials.