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Multiple hot-carrier collection in photo-excited graphene Moiré superlattices

In conventional light-harvesting devices, the absorption of a single photon only excites one electron, which sets the standard limit of power-conversion efficiency, such as the Shockley-Queisser limit. In principle, generating and harnessing multiple carriers per absorbed photon can improve efficien...

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Autores principales: Wu, Sanfeng, Wang, Lei, Lai, You, Shan, Wen-Yu, Aivazian, Grant, Zhang, Xian, Taniguchi, Takashi, Watanabe, Kenji, Xiao, Di, Dean, Cory, Hone, James, Li, Zhiqiang, Xu, Xiaodong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Association for the Advancement of Science 2016
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4928967/
https://www.ncbi.nlm.nih.gov/pubmed/27386538
http://dx.doi.org/10.1126/sciadv.1600002
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author Wu, Sanfeng
Wang, Lei
Lai, You
Shan, Wen-Yu
Aivazian, Grant
Zhang, Xian
Taniguchi, Takashi
Watanabe, Kenji
Xiao, Di
Dean, Cory
Hone, James
Li, Zhiqiang
Xu, Xiaodong
author_facet Wu, Sanfeng
Wang, Lei
Lai, You
Shan, Wen-Yu
Aivazian, Grant
Zhang, Xian
Taniguchi, Takashi
Watanabe, Kenji
Xiao, Di
Dean, Cory
Hone, James
Li, Zhiqiang
Xu, Xiaodong
author_sort Wu, Sanfeng
collection PubMed
description In conventional light-harvesting devices, the absorption of a single photon only excites one electron, which sets the standard limit of power-conversion efficiency, such as the Shockley-Queisser limit. In principle, generating and harnessing multiple carriers per absorbed photon can improve efficiency and possibly overcome this limit. We report the observation of multiple hot-carrier collection in graphene/boron-nitride Moiré superlattice structures. A record-high zero-bias photoresponsivity of 0.3 A/W (equivalently, an external quantum efficiency exceeding 50%) is achieved using graphene’s photo-Nernst effect, which demonstrates a collection of at least five carriers per absorbed photon. We reveal that this effect arises from the enhanced Nernst coefficient through Lifshtiz transition at low-energy Van Hove singularities, which is an emergent phenomenon due to the formation of Moiré minibands. Our observation points to a new means for extremely efficient and flexible optoelectronics based on van der Waals heterostructures.
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spelling pubmed-49289672016-07-06 Multiple hot-carrier collection in photo-excited graphene Moiré superlattices Wu, Sanfeng Wang, Lei Lai, You Shan, Wen-Yu Aivazian, Grant Zhang, Xian Taniguchi, Takashi Watanabe, Kenji Xiao, Di Dean, Cory Hone, James Li, Zhiqiang Xu, Xiaodong Sci Adv Research Articles In conventional light-harvesting devices, the absorption of a single photon only excites one electron, which sets the standard limit of power-conversion efficiency, such as the Shockley-Queisser limit. In principle, generating and harnessing multiple carriers per absorbed photon can improve efficiency and possibly overcome this limit. We report the observation of multiple hot-carrier collection in graphene/boron-nitride Moiré superlattice structures. A record-high zero-bias photoresponsivity of 0.3 A/W (equivalently, an external quantum efficiency exceeding 50%) is achieved using graphene’s photo-Nernst effect, which demonstrates a collection of at least five carriers per absorbed photon. We reveal that this effect arises from the enhanced Nernst coefficient through Lifshtiz transition at low-energy Van Hove singularities, which is an emergent phenomenon due to the formation of Moiré minibands. Our observation points to a new means for extremely efficient and flexible optoelectronics based on van der Waals heterostructures. American Association for the Advancement of Science 2016-05-13 /pmc/articles/PMC4928967/ /pubmed/27386538 http://dx.doi.org/10.1126/sciadv.1600002 Text en Copyright © 2016, The Authors http://creativecommons.org/licenses/by-nc/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license (http://creativecommons.org/licenses/by-nc/4.0/) , 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.
spellingShingle Research Articles
Wu, Sanfeng
Wang, Lei
Lai, You
Shan, Wen-Yu
Aivazian, Grant
Zhang, Xian
Taniguchi, Takashi
Watanabe, Kenji
Xiao, Di
Dean, Cory
Hone, James
Li, Zhiqiang
Xu, Xiaodong
Multiple hot-carrier collection in photo-excited graphene Moiré superlattices
title Multiple hot-carrier collection in photo-excited graphene Moiré superlattices
title_full Multiple hot-carrier collection in photo-excited graphene Moiré superlattices
title_fullStr Multiple hot-carrier collection in photo-excited graphene Moiré superlattices
title_full_unstemmed Multiple hot-carrier collection in photo-excited graphene Moiré superlattices
title_short Multiple hot-carrier collection in photo-excited graphene Moiré superlattices
title_sort multiple hot-carrier collection in photo-excited graphene moiré superlattices
topic Research Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4928967/
https://www.ncbi.nlm.nih.gov/pubmed/27386538
http://dx.doi.org/10.1126/sciadv.1600002
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