Surface plasmon polariton graphene photodetectors

TL;DR

This paper demonstrates a plasmonic graphene photodetector with significantly enhanced responsivity and tunable spectral selectivity by coupling graphene with a plasmonic grating, enabling advanced sensing and optoelectronic applications.

Contribution

It introduces a novel surface plasmon polariton coupling architecture that greatly improves graphene photodetector performance and functionality.

Findings

400% increase in responsivity

1000% increase in photoactive length

Tunable spectral selectivity and new light flux control functionalities

Abstract

The combination of plasmonic nanoparticles and graphene enhances the responsivity and spectral selectivity of graphene-based photodetectors. However, the small area of the metal-graphene junction, where the induced electron-hole pairs separate, limits the photoactive region to sub-micron length scales. Here, we couple graphene with a plasmonic grating and exploit the resulting surface plasmon polaritons to deliver the collected photons to the junction region of a metal-graphene-metal photodetector. This results into a 400% enhancement of responsivity and a 1000% increase in photoactive length, combined with tunable spectral selectivity. The interference between surface plasmon polaritons and the incident wave introduces new functionalities, such as light flux attraction or repulsion from the contact edges, enabling the tailored design of the photodetector's spectral response. This architecture can also be used for surface plasmon bio-sensing with direct-electric- readout, eliminating the need of complicated optics.