Paper
20 February 2012 Ultrafast nonlinear terahertz studies of high-field charge transport in semiconductors
Thomas Elsaesser, Pamela Bowlan, Klaus Reimann, Michael Woerner, Rudolf Hey, Christos Flytzanis
Author Affiliations +
Abstract
Nonlinear terahertz (THz) spectroscopy gives insight into high-field charge transport in semiconductors. Strong THz transients with field amplitudes of up to megavolts/cm serve as a driving field for free carriers and the resulting transport behavior is directly inferred from the field radiated by the moving charges. We study the transition from a ballistic to a drift-like transport regime of electrons in bulk GaAs. While electrons in the lowest conduction band of an n-type sample display ballistic transport, a transition to a drift-like behavior is found in an optically generated electron-hole plasma. Time-resolved measurements reveal the onset of friction on a time scale of a few picoseconds, mainly due to interactions of electrons with the hole distribution heated by the intense THz driving field. Experiments in which photoexcited electrons undergo intervalley scattering from the Γ to the L valley reveal characteristic changes of the transport behavior due to the picosecond backscattering to the Γ valley. The experimental results are in agreement with theoretical calculations of the time-dependent friction including both electron-hole scattering and local-field effects.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Thomas Elsaesser, Pamela Bowlan, Klaus Reimann, Michael Woerner, Rudolf Hey, and Christos Flytzanis "Ultrafast nonlinear terahertz studies of high-field charge transport in semiconductors", Proc. SPIE 8260, Ultrafast Phenomena and Nanophotonics XVI, 82600N (20 February 2012); https://doi.org/10.1117/12.910178
Advertisement
Advertisement
RIGHTS & PERMISSIONS
Get copyright permission  Get copyright permission on Copyright Marketplace
KEYWORDS
Electrons

Terahertz radiation

Gallium arsenide

Plasma

Scattering

Picosecond phenomena

Semiconductors

Back to Top