Graphene transport at high carrier densities using a polymer electrolyte gate

Abstract

We report the study of graphene devices in Hall-bar geometry, gated with a polymer electrolyte. High densities of 6 × 1013/cm2 are consistently reached, significantly higher than with conventional back-gating. The mobility follows an inverse dependence on density, which can be correlated to a dominant scattering from weak scatterers. Furthermore, our measurements show a Bloch-Grüneisen regime until 100 K (at 6.2 × 1013/cm2), consistent with an increase of the density. Ubiquitous in our experiments is a small upturn in resistivity around 3 × 1013/cm2 , whose origin is discussed. We identify two potential causes for the upturn: the renormalization of Fermi velocity and an electrochemically enhanced scattering rate. Copyright © EPLA, 2010.