Atomic-scale evidence for potential barriers and strong carrier scattering at graphene grain boundaries: A scanning tunneling microscopy study

Justin C. Koepke, Joshua D. Wood, David Estrada, Zhun Yong Ong, Kevin T. He, Eric Pop, Joseph W. Lyding

Research output: Contribution to journalArticle

Abstract

We use scanning tunneling microscopy and spectroscopy to examine the electronic nature of grain boundaries (GBs) in polycrystalline graphene grown by chemical vapor deposition (CVD) on Cu foil and transferred to SiO2 substrates. We find no preferential orientation angle between grains, and the GBs are continuous across graphene wrinkles and SiO2 topography. Scanning tunneling spectroscopy shows enhanced empty states tunneling conductance for most of the GBs and a shift toward more n-type behavior compared to the bulk of the graphene. We also observe standing wave patterns adjacent to GBs propagating in a zigzag direction with a decay length of ∼1 nm. Fourier analysis of these patterns indicates that backscattering and intervalley scattering are the dominant mechanisms responsible for the mobility reduction in the presence of GBs in CVD-grown graphene.

Original languageEnglish (US)
Pages (from-to)75-86
Number of pages12
JournalACS Nano
Volume7
Issue number1
DOIs
StatePublished - Jan 22 2013

Keywords

  • CVD
  • grain boundaries
  • graphene
  • scanning tunneling microscopy
  • scattering
  • spectroscopy

ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)

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