Raman study on the g mode of graphene for determination of edge orientation

ACS Nano. 2010 Jun 22;4(6):3175-80. doi: 10.1021/nn100705n.

Abstract

We report a confocal Raman study on edges of single-layer graphene. It is found that edge orientations could be identified by G mode in addition to D mode. We observe that G mode at the edges of single-layer graphene exhibits polar behaviors and different edges such as zigzag- or armchair-dominated responses differently than the polarization of the incident laser. Moreover, G mode shows stiffening at zigzag-dominated edges, while it is softened at armchair-dominated ones. Our observations are in good agreement with recent theory (Sasaki, K. et al. J. Phys. Soc. Jpn. 2010, 79, 044603) and could be well-explained by the unique properties of pseudospin at graphene edges, which lead to asymmetry of Raman active modes and non-adiabatic processes (Kohn Anomaly) at different types of edges. This work could be useful for further study on the properties of the graphene edge and development of graphene-based devices.

MeSH terms

  • Computer Simulation
  • Crystallization / methods*
  • Graphite / chemistry*
  • Light
  • Macromolecular Substances / chemistry
  • Materials Testing
  • Models, Chemical*
  • Molecular Conformation
  • Nanostructures / chemistry*
  • Nanostructures / ultrastructure*
  • Nanotechnology / methods*
  • Particle Size
  • Scattering, Radiation
  • Spectrum Analysis, Raman / methods*
  • Surface Properties

Substances

  • Macromolecular Substances
  • Graphite