Applied Physics

Strained Graphene

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Science  31 Jul 2009:
Vol. 325, Issue 5940, pp. 518
DOI: 10.1126/science.325_518c

When graphene (an extended two-dimensional layer of graphitic carbon) is adsorbed on substrates such as silicon dioxide (SiO2), it can develop strong surface corrugations, and this buckling can create regions of high and low strain. Teague et al. examined the effect of this strain on the conductance properties of graphene adsorbed on SiO2 by first making topographic measurements with a scanning tunneling microscope. A fast Fourier transform of these data produced a strain map of the surface. In unstrained regions, the conductance curves show a sharp inflection at the minimum conductivity and, as in suspended graphene samples, evidence Dirac-like behavior. In the strained regions, however, the effects of out-of-plane phonons mediate the inelastic electron tunneling and help create a broader “U-shaped” conductance curve. The authors note that the effects are relatively small and that strain effects should not prove a barrier to creating graphene devices.

Nano Lett. 9, 2542 (2009).

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