An in-plane photoelectric effect in two-dimensional electron systems for terahertz detection.
American Association for the Advancement of Science
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Michailow, W., Spencer, P., Almond, N. W., Kindness, S. J., Wallis, R., Mitchell, T., Degl'Innocenti, R., et al. (2022). An in-plane photoelectric effect in two-dimensional electron systems for terahertz detection.. Sci Adv, 8 (15) https://doi.org/10.1126/sciadv.abi8398
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 source-drain bias. The observed phenomenon, which we call the "in-plane photoelectric effect," provides an opportunity for efficient direct detection across the entire terahertz range.
Engineering and Physical Sciences Research Council (EP/P021859/1)
European Commission Horizon 2020 (H2020) Future and Emerging Technologies (FET) (881603)
External DOI: https://doi.org/10.1126/sciadv.abi8398
This record's URL: https://www.repository.cam.ac.uk/handle/1810/337224
Attribution-NonCommercial 4.0 International
Licence URL: https://creativecommons.org/licenses/by-nc/4.0/