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Carrier density oscillation in the photoexcited semiconductor

Najafi, Ebrahim and Jafari, Amir and Liao, Bolin (2021) Carrier density oscillation in the photoexcited semiconductor. Journal of Physics D: Applied Physics, 54 (12). Art. No. 125102. ISSN 0022-3727. doi:10.1088/1361-6463/abd1a4.

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The perturbation of a semiconductor from the thermodynamic equilibrium often leads to the display of non-linear dynamics and formation of spatiotemporal patterns due to the spontaneous generation of competing processes. Here, we use scanning ultrafast electron microscopy to show that the transport of hot carriers in the strongly excited semiconductor slows down by turning into an oscillatory process; this is evidenced by the expansions and contractions in the second moment of the distribution. We attribute such a response to the electric field generated by the spatial separation of photo-excited electrons and holes under intrinsic and photo-induced fields; we then introduce a transport model that mimics the experimental observation. Our finding provides a direct imaging evidence for the electrostatic oscillation of hot carriers in the highly excited semiconductor and offers new insights into their dynamics in space and time.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Najafi, Ebrahim0000-0003-3634-9346
Jafari, Amir0000-0003-3370-105X
Liao, Bolin0000-0002-0898-0803
Additional Information:© 2021 IOP Publishing Ltd. Received 20 October 2020; Accepted 8 December 2020; Published 19 January 2021. This work was supported by NSF Grant DMR-0964886 and Air Force Office of Scientific Research Grant FA9550-11-1-0055 in the Physical Biology Center for Ultrafast Science and Technology at California Institute of Technology, which is supported by the Gordon and Betty Moore Foundation. Bolin Laio acknowledges support from the US Department of Energy (Award Number DE-SC0019244) and National Science Foundation (Award Number DMR-1905389). Data availability statement: The data that support the findings of this study are available from the corresponding author upon request.
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)FA9550-11-1-0055
Gordon and Betty Moore FoundationUNSPECIFIED
Department of Energy (DOE)DE-SC0019244
Subject Keywords:ultrafast electron microscopy, surface carrier dynamics, non-equilibrium transport
Issue or Number:12
Record Number:CaltechAUTHORS:20191111-085308090
Persistent URL:
Official Citation:Ebrahim Najafi et al 2021 J. Phys. D: Appl. Phys. 54 125102
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:99770
Deposited By: Tony Diaz
Deposited On:12 Nov 2019 23:20
Last Modified:12 Jul 2022 19:48

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