Femtosecond energy relaxation in suspended graphene : phonon-assisted spreading of quasiparticle distribution

Ultra-fast optical measurements of few-layer suspended graphene films grown by chemical vapor deposition were performed with femtosecond pump–probe spectroscopy. The relaxation processes were monitored in transient differential transmission (ΔT/T) after excitation at two different wavelengths of 350...

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Main Authors: Gurzadyan, Gagik G., Shang, Jingzhi, Yu, Ting
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2013
Online Access:https://hdl.handle.net/10356/95934
http://hdl.handle.net/10220/10763
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-959342020-03-07T12:37:22Z Femtosecond energy relaxation in suspended graphene : phonon-assisted spreading of quasiparticle distribution Gurzadyan, Gagik G. Shang, Jingzhi Yu, Ting School of Physical and Mathematical Sciences Ultra-fast optical measurements of few-layer suspended graphene films grown by chemical vapor deposition were performed with femtosecond pump–probe spectroscopy. The relaxation processes were monitored in transient differential transmission (ΔT/T) after excitation at two different wavelengths of 350 and 680 nm. Intraband electron–electron scattering, electron–phonon scattering, interband Auger recombination and impact ionization were considered to contribute to ΔT/T. All these processes may play important roles in spreading the quasiparticle distribution in time scales up to 100 fs. Optical phonon emission and absorption by highly excited non-equilibrium electrons were identified from ΔT/T peaks in the wide spectral range. When the probe energy region was far from the pump energy, the energy dependence of the quasiparticle decay rate was found to be linear. Longer lifetimes were observed when the quasiparticle population was localized due to optical phonon emission or absorption. 2013-06-27T02:27:35Z 2019-12-06T19:23:29Z 2013-06-27T02:27:35Z 2019-12-06T19:23:29Z 2011 2011 Journal Article Shang, J., Yu, T., & Gurzadyan, G. G. (2012). Femtosecond energy relaxation in suspended graphene: phonon-assisted spreading of quasiparticle distribution. Applied Physics B, 107(1), 131-136. 0946-2171 https://hdl.handle.net/10356/95934 http://hdl.handle.net/10220/10763 10.1007/s00340-011-4853-0 en Applied physics B © 2011 Springer-Verlag.
institution Nanyang Technological University
building NTU Library
country Singapore
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language English
description Ultra-fast optical measurements of few-layer suspended graphene films grown by chemical vapor deposition were performed with femtosecond pump–probe spectroscopy. The relaxation processes were monitored in transient differential transmission (ΔT/T) after excitation at two different wavelengths of 350 and 680 nm. Intraband electron–electron scattering, electron–phonon scattering, interband Auger recombination and impact ionization were considered to contribute to ΔT/T. All these processes may play important roles in spreading the quasiparticle distribution in time scales up to 100 fs. Optical phonon emission and absorption by highly excited non-equilibrium electrons were identified from ΔT/T peaks in the wide spectral range. When the probe energy region was far from the pump energy, the energy dependence of the quasiparticle decay rate was found to be linear. Longer lifetimes were observed when the quasiparticle population was localized due to optical phonon emission or absorption.
author2 School of Physical and Mathematical Sciences
author_facet School of Physical and Mathematical Sciences
Gurzadyan, Gagik G.
Shang, Jingzhi
Yu, Ting
format Article
author Gurzadyan, Gagik G.
Shang, Jingzhi
Yu, Ting
spellingShingle Gurzadyan, Gagik G.
Shang, Jingzhi
Yu, Ting
Femtosecond energy relaxation in suspended graphene : phonon-assisted spreading of quasiparticle distribution
author_sort Gurzadyan, Gagik G.
title Femtosecond energy relaxation in suspended graphene : phonon-assisted spreading of quasiparticle distribution
title_short Femtosecond energy relaxation in suspended graphene : phonon-assisted spreading of quasiparticle distribution
title_full Femtosecond energy relaxation in suspended graphene : phonon-assisted spreading of quasiparticle distribution
title_fullStr Femtosecond energy relaxation in suspended graphene : phonon-assisted spreading of quasiparticle distribution
title_full_unstemmed Femtosecond energy relaxation in suspended graphene : phonon-assisted spreading of quasiparticle distribution
title_sort femtosecond energy relaxation in suspended graphene : phonon-assisted spreading of quasiparticle distribution
publishDate 2013
url https://hdl.handle.net/10356/95934
http://hdl.handle.net/10220/10763
_version_ 1681042943774818304