▎ 摘　　要

We evaluate the degree of disorder in electrolyte-gating devices through 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 that limit the mobility in graphene to 3 x 10(3) cm(2) V-1 s(-1). At higher temperatures (>50 K), phonons in the ionic liquid further reduce the mobility, making its upper limit 2 x 10(3) cm(2)V(-1)s(-1) at room temperature. Since the degree of disorder is independent of the base material, these results are valuable for understanding disorder effects in general devices using electrolyte gating. (C) 2016 The Japan Society of Applied Physics