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Ultrafast carrier thermalization and cooling dynamics in few-layer MoS2

Ultrafast carrier thermalization and cooling dynamics in few-layer MoS2
Ultrafast carrier thermalization and cooling dynamics in few-layer MoS2
Femtosecond optical pump-probe spectroscopy with 10 fs visible pulses is employed to elucidate the earliest ultrafast carrier dynamics in few-layer MoS2. A nonthermal carrier distribution is generated immediately after the photoexcitation. Carrier thermalization is observed to occur on the <20 fs time scale via carrier and phonon scatterings. The excitation pump fluence-dependence study provides evidence for the existence of non-Markovian quantum kinetic behavior in the carrier-carrier scattering process. Subsequent cooling of the hot Fermi-Dirac carrier distribution occurs on the ~0.6 ps time scale via phonon emission on account of the observed hot-phonon effect. Nonadiabatic ab initio molecular dynamics simulations predict time constants of 30 fs and 0.5 ps, respectively, for carrier-carrier and carrier-phonon scatterings, consistent with the assignment of the observed carrier dynamics.
Nie, Z.
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Long, R.
e9f3be8c-53dd-441d-89a8-18d834df4a88
Sun, L.
d80ca5c9-0114-4877-904d-80cec4403a63
Huang, C.C.
825f7447-6d02-48f6-b95a-fa33da71f106
Zhang, J.
722d2564-f8ae-40f1-b1e1-07896b67a0d8
Xiong, Q.
213a6e98-42fd-467f-9323-405db21091c7
Hewak, D.W.
87c80070-c101-4f7a-914f-4cc3131e3db0
Shen, Z.
ec1bb31c-8895-4755-8f29-2d19ce6ad53e
Prezhdo, O.V.
e73b3406-4f64-4a2c-b177-9a7dc5f6a843
Loh, Z-H.
6401b214-aabd-4e63-9ffd-f81559aa13a3
Nie, Z.
a069add2-48c2-431a-a6cb-0692fae7ac02
Long, R.
e9f3be8c-53dd-441d-89a8-18d834df4a88
Sun, L.
d80ca5c9-0114-4877-904d-80cec4403a63
Huang, C.C.
825f7447-6d02-48f6-b95a-fa33da71f106
Zhang, J.
722d2564-f8ae-40f1-b1e1-07896b67a0d8
Xiong, Q.
213a6e98-42fd-467f-9323-405db21091c7
Hewak, D.W.
87c80070-c101-4f7a-914f-4cc3131e3db0
Shen, Z.
ec1bb31c-8895-4755-8f29-2d19ce6ad53e
Prezhdo, O.V.
e73b3406-4f64-4a2c-b177-9a7dc5f6a843
Loh, Z-H.
6401b214-aabd-4e63-9ffd-f81559aa13a3

Nie, Z., Long, R., Sun, L., Huang, C.C., Zhang, J., Xiong, Q., Hewak, D.W., Shen, Z., Prezhdo, O.V. and Loh, Z-H. (2015) Ultrafast carrier thermalization and cooling dynamics in few-layer MoS2. 8th International Conference on Materials for Advanced Technologies (ICMAT 2015) [Materials Research Society of Singapore], Singapore, Singapore. 28 Jun - 04 Jul 2015.

Record type: Conference or Workshop Item (Paper)

Abstract

Femtosecond optical pump-probe spectroscopy with 10 fs visible pulses is employed to elucidate the earliest ultrafast carrier dynamics in few-layer MoS2. A nonthermal carrier distribution is generated immediately after the photoexcitation. Carrier thermalization is observed to occur on the <20 fs time scale via carrier and phonon scatterings. The excitation pump fluence-dependence study provides evidence for the existence of non-Markovian quantum kinetic behavior in the carrier-carrier scattering process. Subsequent cooling of the hot Fermi-Dirac carrier distribution occurs on the ~0.6 ps time scale via phonon emission on account of the observed hot-phonon effect. Nonadiabatic ab initio molecular dynamics simulations predict time constants of 30 fs and 0.5 ps, respectively, for carrier-carrier and carrier-phonon scatterings, consistent with the assignment of the observed carrier dynamics.

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More information

Published date: June 2015
Venue - Dates: 8th International Conference on Materials for Advanced Technologies (ICMAT 2015) [Materials Research Society of Singapore], Singapore, Singapore, 2015-06-28 - 2015-07-04
Organisations: Optoelectronics Research Centre

Identifiers

Local EPrints ID: 379872
URI: https://eprints.soton.ac.uk/id/eprint/379872
PURE UUID: 0fcbab48-9c84-45e4-b9f0-4f1fe44e831f
ORCID for C.C. Huang: ORCID iD orcid.org/0000-0003-3471-2463
ORCID for D.W. Hewak: ORCID iD orcid.org/0000-0002-2093-5773

Catalogue record

Date deposited: 30 Jul 2015 15:33
Last modified: 20 Nov 2018 01:36

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