Angle-resolved raman imaging of interlayer rotations and interactions in twisted bilayer graphene

Robin W. Havener, Houlong Zhuang, Lola Brown, Richard G. Hennig, Jiwoong Park

Research output: Contribution to journalArticle

197 Scopus citations

Abstract

Few-layer graphene is a prototypical layered material, whose properties are determined by the relative orientations and interactions between layers. Exciting electrical and optical phenomena have been observed for the special case of Bernal-stacked few-layer graphene, but structure-property correlations in graphene which deviates from this structure are not well understood. Here, we combine two direct imaging techniques, dark-field transmission electron microscopy (DF-TEM) and widefield Raman imaging, to establish a robust, one-to-one correlation between twist angle and Raman intensity in twisted bilayer graphene (tBLG). The Raman G band intensity is strongly enhanced due to a previously unreported singularity in the joint density of states of tBLG, whose energy is exclusively a function of twist angle and whose optical transition strength is governed by interlayer interactions, enabling direct optical imaging of these parameters. Furthermore, our findings suggest future potential for novel optical and optoelectronic tBLG devices with angle-dependent, tunable characteristics.

Original languageEnglish (US)
Pages (from-to)3162-3167
Number of pages6
JournalNano Letters
Volume12
Issue number6
DOIs
StatePublished - Jun 13 2012

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Keywords

  • Graphene
  • Raman spectroscopy
  • dark-field TEM
  • imaging
  • twisted bilayer

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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