Intrinsic And Extrinsic Performance Limits Of Graphene Devices On Sio 2

The linear dispersion relation in graphene gives rise to a surprising prediction: the resistivity due to isotropic scatterers, such as white-noise disorder or phonons, is independent of carrier density, n. Here we show that electron-acoustic phonon scattering is indeed independent of n, and contributes only 30 Ω to graphene\u27s room-temperature resistivity. At a technologically relevant carrier density of 1 × 1012 cm-2, we infer a mean free path for electron-acoustic phonon scattering of \u3e2 μm and an intrinsic mobility limit of 2 × 105 cm2 V-1 s-1. If realized, this mobility would exceed that of InSb, the inorganic semiconductor with the highest known mobility (∼7.7 × 104 cm2 V-1 s-1; ref. 9) and that of semiconducting carbon nanotubes (∼1 × 105 cm2 V-1 s-1; ref. 10). A strongly temperature-dependent resistivity contribution is observed above ∼200 K (ref. 8); its magnitude, temperature dependence and carrier-density dependence are consistent with extrinsic scattering by surface phonons at the SiO2 substrate and limit the room-temperature mobility to ∼4 × 104 cm2 V-1 s-1, indicating the importance of substrate choice for graphene devices. © 2008 Nature Publishing Group