Ultrafast relaxation of photoexcited carriers in quantum wells and superlattices

The dynamics of photoexcited carriers in GaAs quantum wells and superlattices has been measured with femtosecond resolution using luminescence as well as pump-probe experiments. The electron capture mechanism shows well defined resonances with a time as short as 500 fs at room temperature for a well...

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Bibliographic Details
Published in:Semiconductor science and technology 1994-05, Vol.9 (5S), p.722-726
Main Authors: Deveaud, B, Morris, D, Regreny, A, Planet, R, Gerard, J M, Barros, M R X, Becker, P
Format: Article
Language:English
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Summary:The dynamics of photoexcited carriers in GaAs quantum wells and superlattices has been measured with femtosecond resolution using luminescence as well as pump-probe experiments. The electron capture mechanism shows well defined resonances with a time as short as 500 fs at room temperature for a well thickness of 60 A. This gives strong evidence for the importance of the quantum mechanical LO phonon-assisted capture mechanism predicted by theoretical calculations. In type-II superlattices, we show that the transfer of electrons form the GaAs layers to the AlAs layer is mediated by zone edge phonons (both LO and TA) in a way similar to intervalley scattering. The observed times range from 140 fs up to 30 ps depending on the thickness of the GaAs layer.
ISSN:0268-1242
1361-6641
DOI:10.1088/0268-1242/9/5S/087