Resistivity of Rotated Graphite-Graphene Contacts
Resistivity of Rotated Graphite-Graphene Contacts
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DOI：
10.1021/acs.nanolett.6b01657
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发表时间：
2016-07-01
期刊：
影响因子：
10.8
通讯作者：
Shepard, Kenneth
中科院分区：
文献类型：
--
作者：
Chari, Tarun;Ribeiro-Palau, Rebeca;Shepard, Kenneth
块状导体与二维材料(如石墨烯)的良好电接触对这些二维材料在实际电子器件中的应用至关重要。典型的金属与石墨烯的接触，无论是边缘的还是面状的，产生的电阻率都不高于100欧伽微米，但通常为10千欧微米。在这封信中，我们使用单晶石墨作为与石墨烯的整体接触，而不是传统的金属。石墨触头的转移长度是传统金属触头的四倍。此外，通过调节石墨和石墨烯晶体的相对取向，我们能够将接触电阻率驱动到6.6欧加？m(2)。我们发现，接触电阻率呈现出与晶体对称性相对应的60度周期性，另外，在扭曲的双层石墨烯的公度角中，接触电阻率还急剧下降了约22度和39度。
Robust electrical contact of bulk conductors to two-dimensional (2D) material, such as graphene, is critical to the use of these 2D materials in practical electronic devices. Typical metallic contacts to graphene, whether edge or areal, yield a resistivity of no better than 100 Omega mu m but are typically >10 k Omega mu m. In this Letter, we employ single-crystal graphite for the bulk contact to graphene instead of conventional metals. The graphite contacts exhibit a transfer length up to four-times longer than in conventional metallic contacts. Furthermore, we are able to drive the contact resistivity to as little as 6.6 Omega mu m(2) by tuning the relative orientation of the graphite and graphene crystals. We find that the contact resistivity exhibits a 60 degrees periodicity corresponding to crystal symmetry with additional sharp decreases around 22 degrees and 39 degrees, which are among the commensurate angles of twisted bilayer graphene.