Doping dependence of the Raman spectrum of defected graphene

TL;DR

This study examines how doping levels affect the Raman spectrum of defected graphene, revealing that increased doping reduces D and D' peak intensities due to enhanced electron-electron scattering.

Contribution

It introduces a doping-dependent relation for the D peak intensity in defected graphene, supported by in-situ measurements up to 0.7 eV doping levels.

Findings

D and D' peak intensities decrease with doping

Increased doping enhances electron-electron scattering

Established a general relation between D peak and defects

Abstract

We investigate the evolution of the Raman spectrum of defected graphene as a function of doping. Polymer electrolyte gating allows us to move the Fermi level up to 0.7eV, as monitored by \textit{in-situ} Hall-effect measurements. For a given number of defects, we find that the intensities of the D and D' peaks decrease with increasing doping. We assign this to an increased total scattering rate of the photoexcited electrons and holes, due to the doping-dependent strength of electron-electron scattering. We present a general relation between D peak intensity and defects valid for any doping level