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An in-plane photoelectric effect in two-dimensional electron systems for terahertz detection

Wladislaw Michailow Orcid Logo, Peter Spencer Orcid Logo, Nikita W. Almond Orcid Logo, Stephen J. Kindness Orcid Logo, Robert Wallis, Thomas A. Mitchell Orcid Logo, Riccardo Degl’Innocenti Orcid Logo, Sergey A. Mikhailov Orcid Logo, Harvey E. Beere Orcid Logo, David Ritchie Orcid Logo

Science Advances, Volume: 8, Issue: 15

Swansea University Author: David Ritchie Orcid Logo

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DOI (Published version): 10.1126/sciadv.abi8398

Abstract

Many mid- and far-infrared semiconductor photodetectors rely on a photonic response, when the photon energy is large enough to excite and extract electrons due to optical transitions. Toward the terahertz range with photon energies of a few milli–electron volts, classical mechanisms are used instead...

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Published in: Science Advances
ISSN: 2375-2548
Published: American Association for the Advancement of Science (AAAS) 2022
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URI: https://cronfa.swan.ac.uk/Record/cronfa60432
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Abstract: Many mid- and far-infrared semiconductor photodetectors rely on a photonic response, when the photon energy is large enough to excite and extract electrons due to optical transitions. Toward the terahertz range with photon energies of a few milli–electron volts, classical mechanisms are used instead. This is the case in two-dimensional electron systems, where terahertz detection is dominated by plasmonic mixing and by scattering-based thermal phenomena. Here, we report on the observation of a quantum, collision-free phenomenon that yields a giant photoresponse at terahertz frequencies (1.9 THz), more than 10-fold as large as expected from plasmonic mixing. We artificially create an electrically tunable potential step within a degenerate two-dimensional electron gas. When exposed to terahertz radiation, electrons absorb photons and generate a large photocurrent under zero sourcedrain bias. The observed phenomenon, which we call the “in-plane photoelectric effect,” provides an opportunity for efficient direct detection across the entire terahertz range.
Item Description: Data and materials availability: All data needed to evaluate the conclusions in the paper are present in the paper and/or the Supplementary Materials. The data that support the findings of this study will be available in the Apollo repository of the University of Cambridge at https://doi.org/10.17863/CAM.58046 (65).
College: Faculty of Science and Engineering
Funders: W.M. thanks the George and Lillian Schiff Studentship of the University of Cambridge for financial support and is grateful for the Honorary Vice-Chancellor’s Award of the Cambridge Trust. S.A.M. acknowledges funding from the European Union’s Horizon 2020 research and innovation program Graphene Core 3 under grant agreement no. 881603. R.D. acknowledges support from the EPSRC (grant no. EP/S019383/1). We acknowledge EPSRC funding under the HyperTerahertz grant (no. EP/P021859/1).
Issue: 15