• 文献标题:   Understanding Interlayer Contact Conductance in Twisted Bilayer Graphene
  • 文献类型:   Article
  • 作  者:   YU ZW, SONG AS, SUN LZ, LI YLZ, GAO L, PENG HL, MA TB, LIU ZF, LUO JB
  • 作者关键词:   cafm, graphene, interlayer contact conductance, twist angle
  • 出版物名称:   SMALL
  • ISSN:   1613-6810 EI 1613-6829
  • 通讯作者地址:   Tsinghua Univ
  • 被引频次:   3
  • DOI:   10.1002/smll.201902844 EA SEP 2019
  • 出版年:   2020

▎ 摘  要

Bilayer or few-layer 2D materials showing novel electrical properties in electronic device applications have aroused increasing interest in recent years. Obtaining a comprehensive understanding of interlayer contact conductance still remains a challenge, but is significant for improving the performance of bilayer or few-layer 2D electronic devices. Here, conductive atomic force microscope (C-AFM) experiments are reported to explore the interlayer contact conductance between bilayer graphene (BLG) with various twisted stacking structures fabricated by the chemical vapor deposition (CVD) method. The current maps show that the interlayer contact conductance between BLG strongly depends on the twist angle. The interlayer contact conductance of 0 degrees AB-stacking bilayer graphene (AB-BLG) is approximate to 4 times as large as that of 30 degrees twisted bilayer graphene (t-BLG), which indicates that the twist angle-dependent interlayer contact conductance originates from the coupling-decoupling transitions. Moreover, the moire superlattice-level current images of t-BLG show modulations of local interlayer contact conductance. Density functional theory calculations together with a theoretical model reproduce the C-AFM current map and show that the modulation is mainly attributed to the overall contribution of local interfacial carrier density and tunneling barrier.