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Proceedings Paper

Terahertz conductivity of magnetoexcitons and electrons in semiconductor nanostructures
Author(s): J. Lloyd-Hughes; J. Faist; H. E. Beere; D. A. Ritchie; L. Sirbu; I. M. Tiginyanu; S. K. M. Merchant; M. B. Johnston
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Paper Abstract

Using terahertz time-domain spectroscopy we investigate how quantum, magnetic and electrostatic confinement alters the photoconductivity of nanostructured semiconductors. In 2.0 THz and 2.9THz GaAs/AlGaAs quantum cascade structures under a magnetic field we observe transitions from the 1s to 2p- or 2p+ magneto-exciton states. The electron cyclotron resonance is prominent at high excitation fluence. Additionally, we report that the conductivity of photoexcited electrons in nanoporous InP honeycombs obeys the Drude model of free-carrier absorption, while the dark conductivity does not. This finding can be explained as a result of surface band bending spatially separating photoexcited electrons and holes, and also accounts for the long electron recombination lifetime (exceeding 100 ns) at low temperature.

Paper Details

Date Published: 7 February 2009
PDF: 10 pages
Proc. SPIE 7214, Ultrafast Phenomena in Semiconductors and Nanostructure Materials XIII, 72140N (7 February 2009); doi: 10.1117/12.807546
Show Author Affiliations
J. Lloyd-Hughes, ETH Zürich (Switzerland)
J. Faist, ETH Zürich (Switzerland)
H. E. Beere, Univ. of Cambridge (United Kingdom)
D. A. Ritchie, Univ. of Cambridge (United Kingdom)
L. Sirbu, Technical Univ. of Moldova (Moldova)
Institute of Applied Physics (Moldova)
I. M. Tiginyanu, Technical Univ. of Moldova (Moldova)
Institute of Applied Physics (Moldova)
S. K. M. Merchant, Univ. of Oxford (United Kingdom)
M. B. Johnston, Univ. of Oxford (United Kingdom)

Published in SPIE Proceedings Vol. 7214:
Ultrafast Phenomena in Semiconductors and Nanostructure Materials XIII
Kong-Thon Tsen; Jin-Joo Song; Markus Betz; Abdulhakem Y. Elezzabi, Editor(s)

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