10.1021/jp412559u.s001
Won-Hwa Park
Won-Hwa
Park
Quantification
of the Relative <i>z</i>‑Polarized
Electromagnetic Field Contribution and Associated Investigation of
Asymmetric Shape of Layer Breathing Mode from Au Nanoparticle–Graphene–Au
Thin Film Junctions
American Chemical Society
2014
electron density
TF junction
z axis
ILBM
graphene sheet
SERS
Film JunctionsSimultaneous utilization
EM
layer breathing mode
field contribution
NP
Layer Breathing Mode
Associated Investigation
LBM peak
Asymmetric Shape
characterization tool
2 D materials
phonon
graphene layers
2014-04-03 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Quantification_of_the_Relative_i_z_i_Polarized_Electromagnetic_Field_Contribution_and_Associated_Investigation_of_Asymmetric_Shape_of_Layer_Breathing_Mode_from_Au_Nanoparticle_Graphene_Au_Thin_Film_Junctions/2309605
Simultaneous utilization of both
in-plane and out-of-plane phonon
vibration of graphene sandwiched between a Au nanoparticle (NP) and
Au TF junction can have a significant role in quantifying the <i>z</i>-polarized electromagnetic (EM) field contribution. The
layer breathing mode (LBM), which involves the relative displacement
of the individual graphene layers in the graphene sheet in the normal
directions, can be exclusively observed at Au NP–Au TF junctions.
By employing the <i>I</i><sub>LBM</sub>/<i>I</i><sub>2D</sub> value at each junction, the author can show that a
nearly 50–70-times stronger <i>z</i>-polarized EM
contribution is present at Au NP–Au TF junctions. Additionally,
the author can also determine that a Au NP with a truncated shape
shows a relatively ∼1.3-times higher <i>z</i>-polarized
EM contribution than a Au NP with a spherical shape because of the
higher density of the pointed part from the truncated Au NP. Furthermore,
the author reveals the evolution of the asymmetric shape of the LBM
peak with increasing <i>z</i>-polarized EM strength. The
increase of the full width at half-maximum (fwhm) from the major LBM
and the correlated blue shift of the minor LBM with increasing <i>z</i>-polarized EM contribution imply that the degree of coupling
between highly localized electrons and low-energy phonons from graphene
along the <i>z</i> axis might be reflected and that of the
additional n-doped status of graphene stemming from the relatively
higher electron density at truncated sites within Au NP might also
be reflected. The author is currently developing this surface-enhanced-Raman-scattering-
(SERS-) based nanometrology as a more facile optical characterization
tool, especially for exploring out-of-plane phonon vibration of various
2D materials.