Analytical modeling and experimental characterization of drift in electrolyte-gated graphene field-effect transistors

Electrolyte-gated graphene field-effect transistors are increasingly attractive as platforms for high-sensitivity and low-detection limit biosensing or in synaptic or memristive elements used in neuromorphic computing. However, their electrical stability and noise have yet to be thoroughly analyzed and understood. In this work, we have undertaken a comprehensive experimental characterization of the dynamic response of the drift in electrolyte-gated graphene field-effect transistors under various measurement conditions. We then developed an analytical model, which was phenomenologically validated for all observed drift phenomena and fitted to the experimental data. The model is based on charge trapping at the silicon oxide substrate defects in contact with the graphene channel. The electron transitions are made possible by the absorption of phonons to overcome the energetic barrier leading to the new state. This in-depth understanding of these devices’ responses is essential to fully exploit their behavior in applications and standardize practices amongst the community.