Biomolecular Control Over Local Gating in Bilayer Graphene Induced by Ferritin

Abstract

Electrical field-induced charge modulation in graphene-based devices at the nanoscale with ultrahigh density carrier accumulation is important for various practical applications. In bilayer graphene (BLG), inversion symmetry can simply be broken by an external electric field. However, control over charge carrier density at the nanometer scale is a challenging task. Here, we demonstrate local gating of bilayer graphene (BLG) in the nanometer range by adsorption of AfFtn-AA (which is a bio-engineered ferritin, an iron storing globular protein with ∅ = 12 nm). Low-temperature electrical transport measurements with field effect transistors with these AfFtn-AA/BLG surfaces show hysteresis with two Dirac peaks. One peak at a gate voltage Vg = 35 V is associated with pristine BLG, while the second peak at Vg = 5 V results from local doping by ferritin. This charge trapping at the biomolecular length-scale offers a straightforward and non-destructive method to alter the local electronic structure of BLG.