Field effect and local gating in nitrogen-terminated nanopores (NtNP) and nanogaps (NtNG) in graphene

Single-molecule biosensing, with a promise of being applied in protein and DNA sequencing, could be achieved using tunneling current approach. Electrode-molecule-electrode tunneling current critically depends on whether molecular levels contribute to electronic transport or not. Here we found employing DFT and Non-Equilibrium Green's Function formalism that energies of benzene molecular levels placed between graphene electrodes are strongly influenced by electrode termination. Termination-dependent dipoles formed at the electrode ends induce in-gap field effect that is responsible for shifting of molecular levels. We show that the HOMO is closest to Fermi energy for nitrogen-terminated nanogaps (NtNGs) and nanopores (NtNPs), promoting them as strong candidates for single-molecule sensing applications.