Spatial mapping of the Dirac point in monolayer and bilayer graphene

Aparna Deshpande, Wenzhong Bao, Zeng Zhao, Chun Ning Lau, Brian Leroy

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


We have mapped the Dirac point in exfoliated monolayer and bilayer graphene using spatially resolved scanning tunneling spectroscopy measurements at low temperature. The Dirac-point shifts in energy at different locations in graphene. However, a cross correlation with the topography shows no correlation indicating that topographic features, such as ripples are not the primary source of the variation. Rather, we attribute the shift of the Dirac point to random charged impurities located near the graphene. Our findings emphasize the need to advance exfoliated graphene sample preparation to minimize the effect of impurities.

Original languageEnglish (US)
Article number5504843
Pages (from-to)88-91
Number of pages4
JournalIEEE Transactions on Nanotechnology
Issue number1
StatePublished - Jan 2011


  • Dirac point
  • graphene
  • scanning tunneling microscope (STM)
  • spectroscopy

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering


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