Doping dependence of the Raman peaks intensity of graphene near the Dirac point

TL;DR

This study investigates how doping affects the Raman peak intensities in pristine graphene near the Dirac point, revealing that the G peak remains constant while the 2D peak diminishes with increased doping, linked to electron-phonon interactions.

Contribution

It provides new insights into the doping dependence of Raman intensities in graphene, especially near the Dirac point, using pristine samples and resonant process analysis.

Findings

G peak intensity is doping-independent

2D peak intensity decreases with doping

Electron-phonon scattering rate is ~40 meV at 2.4 eV

Abstract

Here we use pristine graphene samples in order to analyze how the Raman peaks intensity, measured at 2.4 eV and 1.96 eV excitation energy, changes with the amount of doping. The use of pristine graphene allows investigating the intensity dependence close to the Dirac point. We show that the G peak intensity is independent on the doping, while the 2D peak intensity strongly decreases for increasing doping. Analyzing this dependence in the framework of a fully resonant process, we found that the total electron-phonon scattering rate is ~40 meV at 2.4 eV.