The ultrafast dynamics and conductivity of photoexcited graphene at different Fermi energies
dc.contributor.author | Tomadin, A | |
dc.contributor.author | Hornett, SM | |
dc.contributor.author | Wang, HI | |
dc.contributor.author | Alexeev, EM | |
dc.contributor.author | Candini, A | |
dc.contributor.author | Coletti, C | |
dc.contributor.author | Turchinovich, D | |
dc.contributor.author | Klaeui, M | |
dc.contributor.author | Bonn, M | |
dc.contributor.author | Koppens, FHL | |
dc.contributor.author | Hendry, E | |
dc.contributor.author | Polini, M | |
dc.contributor.author | Tielrooij, KJ | |
dc.date.accessioned | 2019-01-16T16:55:17Z | |
dc.date.issued | 2018-05-11 | |
dc.description.abstract | For many of the envisioned optoelectronic applications of graphene it is crucial to understand the sub-picosecond carrier dynamics immediately following photoexcitation, as well as the effect on the electrical conductivity - the photoconductivity. Whereas these topics have been studied using various ultrafast experiments and theoretical approaches, controversial and incomplete explanations have been put forward concerning the sign of the photoconductivity, the occurrence and significance of the creation of additional electron-hole pairs, and, in particular, how the relevant processes depend on Fermi energy. Here, we present a unified and intuitive physical picture of the ultrafast carrier dynamics and the photoconductivity, combining optical pump - terahertz probe measurements on a gate-tunable graphene device, with numerical calculations using the Boltzmann equation. We distinguish two types of ultrafast photo-induced carrier heating processes: At low (equilibrium) Fermi energy ($E_{\rm F} \lesssim$ 0.1 eV for our experiments) broadening of the carrier distribution involves interband transitions - interband heating. At higher Fermi energy ($E_{\rm F} \gtrsim$ 0.15 eV) broadening of the carrier distribution involves intraband transitions - intraband heating. Under certain conditions, additional electron-hole pairs can be created (carrier multiplication) for low $E_{\rm F}$, and hot carriers (hot-carrier multiplication) for higher $E_{\rm F}$. The resultant photoconductivity is positive (negative) for low (high) $E_{\rm F}$, which originates from the effect of the heated carrier distributions on the screening of impurities, consistent with the DC conductivity being mostly due to impurity scattering. The importance of these insights is highlighted by a discussion of the implications for graphene photodetector applications. | en_GB |
dc.description.sponsorship | European Union Horizon 2020 | en_GB |
dc.description.sponsorship | Severo Ochoa Programme for Centres of Excellence in R&D | en_GB |
dc.description.sponsorship | Mineco grants Ramon y Cajal | en_GB |
dc.description.sponsorship | Spanish Ministry of Economy and Competitiveness | en_GB |
dc.description.sponsorship | Government of Catalonia | en_GB |
dc.description.sponsorship | European Research Council StG CarbonLight | en_GB |
dc.description.sponsorship | German Research Foundation | en_GB |
dc.description.sponsorship | State Research Centre for Innovative and Emerging Materials and the Graduate School of Excellence Materials Science in Mainz (MAINZ) | en_GB |
dc.description.sponsorship | Engineering and Physical Sciences Research Council (EPSRC) | en_GB |
dc.description.sponsorship | Mineco | en_GB |
dc.identifier.citation | Vol.4 (5), article eaar 5313 | en_GB |
dc.identifier.doi | 10.1126/sciadv.aar5313 | |
dc.identifier.grantnumber | 696656 | en_GB |
dc.identifier.grantnumber | FP7-ICT-2013-613024-GRASP | en_GB |
dc.identifier.grantnumber | FET-ICT-2013-10 610449 | en_GB |
dc.identifier.grantnumber | SEV-2015-0522 | en_GB |
dc.identifier.grantnumber | RYC-2012-12281 | en_GB |
dc.identifier.grantnumber | FIS2013-47161-P | en_GB |
dc.identifier.grantnumber | 2014-SGR-1535 | en_GB |
dc.identifier.grantnumber | 307806 | en_GB |
dc.identifier.grantnumber | SPP 1459 | en_GB |
dc.identifier.grantnumber | GSC 266 | en_GB |
dc.identifier.grantnumber | EP/K041215/1 | en_GB |
dc.identifier.grantnumber | FIS2014-59639-JIN | en_GB |
dc.identifier.grantnumber | SFB TRR173 | |
dc.identifier.uri | http://hdl.handle.net/10871/35496 | |
dc.language.iso | en | en_GB |
dc.publisher | American Association for the Advancement of Science (AAAS) | en_GB |
dc.rights | Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited. | en_GB |
dc.subject | cond-mat.mes-hall | en_GB |
dc.subject | cond-mat.mes-hall | en_GB |
dc.subject | photoexcited graphene | en_GB |
dc.subject | Fermi energies | en_GB |
dc.title | The ultrafast dynamics and conductivity of photoexcited graphene at different Fermi energies | en_GB |
dc.type | Article | en_GB |
dc.date.available | 2019-01-16T16:55:17Z | |
dc.description | This is the final version. A vailable from the American Association for the Advancement of Science via the DOI in this record. | en_GB |
dc.identifier.eissn | 2375-2548 | |
dc.identifier.journal | Science Advances | en_GB |
dc.rights.uri | https://creativecommons.org/licenses/by-nc/4.0/ | en_GB |
dcterms.dateAccepted | 2018-03-23 | |
rioxxterms.version | VoR | en_GB |
rioxxterms.licenseref.startdate | 2018-05-11 | |
rioxxterms.type | Journal Article/Review | en_GB |
refterms.dateFCD | 2019-01-16T16:31:36Z | |
refterms.versionFCD | AM | |
refterms.dateFOA | 2019-01-16T16:55:25Z | |
refterms.dateFirstOnline | 2018-05-23 |
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Except where otherwise noted, this item's licence is described as Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).
This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.