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-Gr\"uneisen 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.
@article{arxiv.1009.3367,
title = {Graphene Transport at High Carrier Densities using a Polymer Electrolyte Gate},
author = {Alexandre Pachoud and Manu Jaiswal and Priscilla Kailian Ang and Kian Ping Loh and Barbaros Oezyilmaz},
journal= {arXiv preprint arXiv:1009.3367},
year = {2010}
}