Origins of Leakage Currents on Electrolyte-Gated Graphene Field-Effect Transistors

Graphene field-effect transistors are widely used for development of biosensors. However, certain fundamental questions about details their functioning have not been fully understood yet. One these is the presence gate/leakage currents in electrolyte-gated configuration. Here, we report our observations and causes this phenomenon on chemical vapor deposition (CVD)-grown graphene. We observed transistor’s gate occurring at surface graphene exposed to electrolyte. Gate capacitive when channel doped by holes Faradic it electrons measurements. prove that attributed reduction oxygen dissolved aqueous solution magnitude increases with each measurement. employed cyclic voltammetry a redox probe Fc(MeOH)2 characterize changes structure responsible activation. Collectively, results reveal through course catalytic surface, its electroactivity toward an out-of-plane heterogeneous electron transfer increases.