Direct Imaging of Graphene Edges: Atomic Structure and Electronic Scattering

Jifa Tian, Birck Nanotechnology Center, Purdue University
Helin Cao, Birck Nanotechnology Center, Purdue University
Wei Wu, University of Houston
Qingkai Yu, University of Houston
Yong P. Chen, Birck Nanotechnology Center, Purdue University

Abstract

We report an atomically resolved scanning tunneling microscopy investigation of the edges of graphene grains synthesized on Cu foils by chemical vapor deposition. Most of the edges are macroscopically parallel to the zigzag directions of graphene lattice. These edges have microscopic roughness that is found to also follow zigzag directions at atomic scale, displaying many similar to 120 degrees turns. A prominent standing wave pattern with periodicity similar to 3a/4 (a being the graphene lattice constant) is observed near a rare-occurring armchair-oriented edge. Observed features of this wave pattern are consistent with the electronic intervalley backscattering predicted to occur at armchair edges but not at zigzag edges.

Discipline(s)

Nanoscience and Nanotechnology