Raman Spectroscopy of Graphene Edges

TL;DR

This study uses Raman spectroscopy to analyze the properties of graphene edges, revealing how their orientation affects Raman signals and highlighting the microscopic disorder of edges despite macroscopic smoothness.

Contribution

It provides a detailed Raman analysis of graphene edges with different orientations, emphasizing the relationship between edge chirality and Raman spectral features.

Findings

D-band intensity varies with light polarization relative to the edge

D peak is localized near the edge as shown by Raman mapping

Edge orientation does not always correlate with D to G ratio

Abstract

Graphene edges are of particular interest, since their chirality determines the electronic properties. Here we present a detailed Raman investigation of graphene flakes with well defined edges oriented at different crystallographic directions. The position, width and intensity of G and D peaks at the edges are studied as a function of the incident light polarization. The D-band is strongest for light polarized parallel to the edge and minimum for perpendicular orientation. Raman mapping shows that the D peak is localized in proximity of the edge. The D to G ratio does not always show a significant dependence on edge orientation. Thus, even though edges can appear macroscopically smooth and oriented at well defined angles, they are not necessarily microscopically ordered.