Disorder from the Bulk Ionic Liquid in Electric Double Layer Transistors

Ionic liquid gating has a number of advantages over solid-state gating, especially for flexible or transparent devices, and for applications requiring high carrier densities. However, the large number of charged ions near the channel inevitably results in Coulomb scattering, which limits the carrier mobility in otherwise clean systems. We develop a model for this Coulomb scattering. We validate our model experimentally using ionic liquid gating of graphene across varying thicknesses of hexagonal boron nitride, demonstrating that disorder in the bulk ionic liquid often dominates the scattering.