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Inefficiency of intervalley transfer in narrow InGaAs/AlAsSb quantum wells

: Tribuzy, C.V.-B.; Ohser, S.; Priegnitz, M.; Winnerl, S.; Schneider, H.; Helm, M.; Neuhaus, J.; Dekorsy, T.; Biermann, K.; Künzel, H.


Physica status solidi. C 5 (2008), No.1, pp.229-231
ISSN: 1610-1634
ISSN: 1610-1642
ISSN: 1862-6351
International Conference on Nonequilibrium Carrier Dynamics in Semiconductors (HCIS) <15, 2007, Tokyo>
Conference Paper, Journal Article
Fraunhofer HHI ()

By using femtosecond pump-probe spectroscopy we investigate the intersubband relaxation dynamics in narrow InGaAs/AlAsSb quantum wells. A biexponential behavior is an indication of intervalley scattering, which is, however, much slower than known from bulk material. This may be the reason why quantum cascade lasers at wavelengths as short as 3 m are actually functioning In addition, when pumping slightly below resonance we observe an induced transient absorption, which can be interpreted in terms of electron heating within the first subband.