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Observation of low‐wavenumber out‐of‐plane optical phonon in few‐layer graphene
Author(s) -
Shang Jingzhi,
Cong Chunxiao,
Zhang Jun,
Xiong Qihua,
Gurzadyan Gagik G.,
Yu Ting
Publication year - 2013
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4141
Subject(s) - wavenumber , raman spectroscopy , phonon , graphene , raman scattering , condensed matter physics , materials science , molecular physics , coherent anti stokes raman spectroscopy , chemistry , optics , physics , nanotechnology
Few‐layer graphene grown by chemical vapor deposition has been studied by Raman and ultrafast laser spectroscopy. A low‐wavenumber Raman peak of ~120 cm −1 and a phonon‐induced oscillation in the kinetic curve of electron–phonon relaxation process have been observed, respectively. The Raman peak is assigned to the low‐wavenumber out‐of‐plane optical mode in the few‐layer graphene. The phonon band shows an asymmetric shape, a consequence of so‐called Breit‐Wigner‐Fano resonance, resulting from the coupling between the low‐wavenumber phonon and electron transitions. The obtained oscillation wavenumber from the kinetic curve is consistent with the detected low‐wavenumber phonon by Raman scattering. The origin of this oscillation is attributed to the generation of coherent phonons and their interactions with photoinduced electrons. Copyright © 2012 John Wiley & Sons, Ltd.