Friction Anisotropy–Driven Domain Imaging on Exfoliated Monolayer Graphene

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Science  30 Jun 2011:
DOI: 10.1126/science.1207110


Graphene produced by exfoliation has not been able to provide an ideal graphene with performance comparable to that predicted by theory, and structural and/or electronic defects have been proposed as one cause of reduced performance. We report the observation of domains on exfoliated monolayer graphene that differ by their friction characteristics, as measured by friction force microscopy. Angle-dependent scanning revealed friction anisotropy with a periodicity of 180 degrees on each friction domain. The friction anisotropy decreased as the applied load increased. We propose that the domains arise from ripple distortions that give rise to anisotropic friction in each domain due to the anisotropic puckering of the graphene.