Open AccessSensitive Raman Probe of Electronic Interactions between Monolayer Graphene and Substrate under Electrochemical Potential Control
Author(s) -
Ronggang Zhou,
Satoshi Yasuda,
Hiro Minamimoto,
Kei Murakoshi
Publication year - 2018
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.7b01928
Subject(s) - graphene , raman spectroscopy , materials science , monolayer , electrochemistry , substrate (aquarium) , electrochemical potential , fermi level , nanotechnology , chemical physics , metal , analytical chemistry (journal) , electrode , chemistry , optics , organic chemistry , physics , oceanography , quantum mechanics , geology , metallurgy , electron
In situ electrochemical Raman spectroscopic measurements of defect-free monolayer graphene on various substrates were performed under electrochemical potential control. The G and 2D Raman band wavenumbers (ω G , ω 2D ) of graphene were found to depend upon the electrochemical potential, i.e., the charge density of graphene. The values of ω G and ω 2D also varied depending on the choice of substrates. On metal substrates where graphene was synthesized by chemical vapor deposition, a strong blue shift of ω 2D was induced, which could not account for the strain and charge doping. We attributed the blue shift of ω 2D to a change in the electronic properties of graphene induced by distinct electronic interactions with the metal substrates. To explain the unique characteristics in the Raman spectrum of graphene on various substrates, a novel mechanism is proposed considering reduction of the Fermi velocity in graphene owing to dielectric screening from the metal substrates.