Graphene Nanogap for Gate Tunable Quantum Coherent Single Molecule Electronics

TL;DR

This paper demonstrates that graphene nanogaps can be used as gate-tunable, quantum coherent single-molecule electronic devices, addressing key challenges in molecular electronics with novel contact and control mechanisms.

Contribution

The study introduces atomistic calculations showing how graphene contacts enable effective gating, size matching, and charge flow detection in single-molecule electronics.

Findings

Graphene contacts allow high on/off current ratios in molecular transistors.

Gate modulation of Fermi level controls device conductance.

Charge flow patterns are detectable by scanning techniques.

Abstract

We present atomistic calculations of quantum coherent electron transport through fulleropyrrolidine terminated molecules bridging a graphene nanogap. We predict that three difficult problems in molecular electronics with single molecules may be solved by utilizing graphene contacts: (1) a back gate modulating the Fermi level in the graphene leads facilitate control of the device conductance in a transistor effect with high on/off current ratio; (2) the size mismatch between leads and molecule is avoided, in contrast to the traditional metal contacts; (3) as a consequence, distinct features in charge flow patterns throughout the device are directly detectable by scanning techniques. We show that moderate graphene edge disorder is unimportant for the transistor function.