Evaluation of Disorder Introduced by Electrolyte Gating through Transport Measurements in Graphene

Andrew Browning, Norio Kumada, Yoshiaki Sekine, Hiroshi Irie, Koji Muraki, Hideki Yamamoto

Published 2016-04-11Version 1

We evaluate the degree of disorder in electrolyte gating devices through the transport measurements in graphene. By comparing the mobility in ion- and standard metal-gated devices, we show that the deposition of the ionic liquid introduces charged impurities with a density of approximately $6\times 10^{12}$ cm$^{-2}$; setting the upper limit of the mobility in graphene to 3000 cm$^2$/Vs. At higher temperature, phonons in the ionic liquid further reduce the mobility, making its upper limit 2000 cm$^2$/Vs at room temperature. Since the degree of disorder is independent of the base material, these results are valuable towards understanding disorder effects in general devices using electrolyte gating.