Raman spectroscopy on etched graphene nanoribbons

TL;DR

This study uses confocal Raman spectroscopy to analyze etched graphene nanoribbons, revealing edge-specific defect signals, the impact of fabrication on bulk quality, and potential methods to determine crystallographic orientation.

Contribution

It demonstrates that D-line intensity relates to edges without bulk defects and introduces polarization measurements to analyze nanoribbon edges.

Findings

D-line intensity depends on edge regions

G- and 2D-lines scale with ribbon width

D-to-G ratio indicates crystallographic orientation

Abstract

We investigate etched single-layer graphene nanoribbons with different widths ranging from 30 to 130 nm by confocal Raman spectroscopy. We show that the D-line intensity only depends on the edge-region of the nanoribbon and that consequently the fabrication process does not introduce bulk defects. In contrast, the G- and the 2D-lines scale linearly with the irradiated area and therefore with the width of the ribbons. We further give indications that the D- to G-line ratio can be used to gain information about the crystallographic orientation of the underlying graphene. Finally, we perform polarization angle dependent measurements to analyze the nanoribbon edge-regions.