Edge and surface plasmons in graphene nanoribbons

TL;DR

This study uses nano-IR imaging to explore confined and edge plasmons in high-quality graphene nanoribbons, revealing how geometry and substrate phonons influence plasmon modes and damping.

Contribution

It provides detailed experimental insights into the behavior of confined and edge plasmons in graphene nanoribbons, highlighting the effects of geometry and substrate interactions.

Findings

Confined plasmon modes depend systematically on ribbon width.

Edge plasmons propagate strictly along ribbon edges.

Substrate phonons influence plasmon damping.

Abstract

We report on nano-infrared (IR) imaging studies of confined plasmon modes inside patterned graphene nanoribbons (GNRs) fabricated with high-quality chemical-vapor-deposited (CVD) graphene on Al2O3 substrates. The confined geometry of these ribbons leads to distinct mode patterns and strong field enhancement, both of which evolve systematically with the ribbon width. In addition, spectroscopic nano-imaging in mid-infrared 850-1450 cm-1 allowed us to evaluate the effect of the substrate phonons on the plasmon damping. Furthermore, we observed edge plasmons: peculiar one-dimensional modes propagating strictly along the edges of our patterned graphene nanostructures.