Fast, reliable, and inexpensive DNA sequencing is an important pursuit in healthcare, especially in personalized medicine with possible deep societal impacts. Despite significant progress in various nanopore-based sequencing configurations, challenges that remain in resolution and chromosome-size-long readout call for new approaches. Here we found strong rectification in the transversal current during single-stranded DNA translocation through a nanopore with side-embedded N-terminated carbon nanotube electrodes. Employing density functional theory and nonequilibrium Green's function formalisms, we show that the rectifying ratio (response to square pulses of alternating bias) bears high nucleobase specificity. Rectification arises because of bias-dependent resistance asymmetry on the deoxyribonucleotide−electrode interfaces. The asymmetry induces molecular charging and highest occupied molecular orbital pinning to the electrochemical potential of one of the electrodes, assisted by an in-gap electric-field effect caused by dipoles at the terminated electrode ends. We propose the rectifying ratio, due to its order-of-magnitude-difference nucleobase selectivity and robustness to electrode-molecule orientation, as a promising readout quantifier for single-base resolution and chromosome-size-long single-read DNA sequencing. The proposed configurations are within experimental reach from the viewpoint of both nanofabrication and small current measurement.

Functionalization of electrodes is a wide‐used strategy in various applications ranging from single‐molecule sensing and protein sequencing, to ion trapping, to desalination. We demonstrate, employing non‐equilibrium Green′s function formalism combined with density functional theory, that single‐species (N, H, S, Cl, F) termination of graphene nanogap electrodes results in a strong in‐gap electrostatic field, induced by species‐dependent dipoles formed at the electrode ends. Consequently, the field increases or decreases electronic transport through a molecule (benzene) placed in the nanogap by shifting molecular levels by almost 2 eV in respect to the electrode Fermi level via a field effect akin to the one used for field‐effect transistors. We also observed the local gating in graphene nanopores terminated with different single‐species atoms. Nitrogen‐terminated nanogaps (NtNGs) and nanopores (NtNPs) show the strongest effect. The in‐gap potential can be transformed from a plateau‐like to a saddle‐like shape by tailoring NtNG and NtNP size and termination type. In particular, the saddle‐like potential is applicable in single‐ion trapping and desalination devices.

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