Title
Raman spectra and electron-phonon coupling in disordered graphene with gate-tunable doping
Date Issued
21 December 2014
Access level
open access
Resource Type
journal article
Author(s)
Childres I.
Chen Y.P.
School of Electrical and Computer Engineering
Publisher(s)
American Institute of Physics Inc.
Abstract
We report a Raman spectroscopy study of graphene field-effect transistors with a controlled amount of defects introduced in graphene by exposure to electron-beam irradiation. Raman spectra are taken at T=8K over a range of back gate voltages (Vg) for various irradiation dosages (Re). We study effects in the Raman spectra due to Vg-induced doping and artificially created disorder at various Re. With moderate disorder (irradiation), the Raman G peak with respect to the graphene carrier density (nFE) exhibits a minimum in peak frequency and a maximum in peak width near the charge-neutral point (CNP). These trends are similar to those seen in previous works on pristine graphene and have been attributed to a reduction of electron-phonon coupling strength (D) and removal of the Kohn anomaly as the Fermi level moves away from the CNP. We also observe a maximum in I2D/IG and weak maximum in ID/IG near the CNP. All the observed dependences of Raman parameters on nFE weaken at stronger disorder (higher Re), implying that disorder causes a reduction of D as well. Our findings are valuable for understanding Raman spectra and electron-phonon physics in doped and disordered graphene.
Volume
116
Issue
23
Language
English
OCDE Knowledge area
Ingeniería de sistemas y comunicaciones
Scopus EID
2-s2.0-84920287568
Source
Journal of Applied Physics
ISSN of the container
00218979
Sources of information: Directorio de Producción Científica Scopus