Suspended electrolyte-gated graphene field-effect transistors for drift mitigation and enhanced electrical performance

Abstract In this work, we present a simple, reliable fabrication process for suspended electrolyte-gated graphene field-effect transistors with a critical dimension of 20 µ m and a high yield. After suspension, these devices can be electrically actuated with a coplanar gold gate or a silicon back gate, exhibiting improved electrical conductivity, carrier mobility, and transconductance, as well as reduced drift due to reduced interactions between charge carriers and substrate defects. In addition, they exhibit remarkable structural resilience and remain fully operational after successive cleaning steps and after evaporation or the addition of electrolyte media. We fit two distinct analytical models to the experimental data and show that the improved transfer curve conductance and mitigated drift in the suspended devices can be explained by a reduction in scattering centres and defect concentration to approximately one-third of the original number in their non-suspended counterparts.