Photon-Assisted Tunneling through Molecular Conduction Junctions with Graphene Electrodes

TL;DR

This paper explores how graphene electrodes can enhance photon-assisted tunneling in molecular junctions, enabling control of photocurrent and potentially advancing single-molecule electronic devices.

Contribution

It introduces the use of graphene electrodes for photon-assisted tunneling, highlighting their ability to modify current via side-band energies and control photocurrent polarization.

Findings

Dramatic increase in current at side-band energies due to graphene's spectrum modification

Polarization control of photocurrent using doped graphene electrodes

Surface plasmon excitation enhances process efficiency

Abstract

Graphene electrodes provide a suitable alternative to metal contacts in molecular conduction nanojunctions. Here, we propose to use graphene electrodes as a platform for effective photon assisted tunneling through molecular conduction nanojunctions. We predict dramatic increasing currents evaluated at side-band energies $\sim n\hbar\omega$ ($n$ is a whole number) related to the modification of graphene gapless spectrum under the action of external electromagnetic field of frequency $\omega$. A side benifit of using doped graphene electrodes is the polarization control of photocurrent related to the processes occurring either in the graphene electrodes or in the molecular bridge. The latter processes are accompanied by surface plasmon excitation in the graphene sheet that makes them more efficient. Our results illustrate the potential of graphene contacts in coherent control of photocurrent in molecular electronics, supporting the possibility of single-molecule devices.