iScience (Apr 2022)

Biomolecular control over local gating in bilayer graphene induced by ferritin

  • Senthil Kumar Karuppannan,
  • Jens Martin,
  • Wentao Xu,
  • Rupali Reddy Pasula,
  • Sierin Lim,
  • Christian A. Nijhuis

Journal volume & issue
Vol. 25, no. 4
p. 104128

Abstract

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Summary: 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. We demonstrate local gating of BLG in the nanometer range by adsorption of AfFtnAA (which is a bioengineered ferritin, an iron-storing globular protein with ∅ = 12 nm). Low-temperature electrical transport measurements with field-effect transistors with these AfFtnAA/BLG surfaces show hysteresis with two Dirac peaks. One peak at a gate voltage VBG = 35 V is associated with pristine BLG, while the second peak at VBG = 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.

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