Strong generation of coherent acoustic phonons in semiconductor quantum dots.
We present experimental results obtained in two-color pump-probe experiments performed in semiconductor self-assembled quantum dot (QD) layers. The sample reflectivities present several acoustic contributions, among which are strong acoustic phonon wave packets. A comparison between one- and two-color experiments and a fine analysis of the echo shape attest that a high magnitude phonon pulse emerges from each single QD layer. This conclusion is supported by a numerical modeling which perfectly reproduces our experimental signals only if we introduce a strong generation in each QD layer. We explain such a strong emission thanks to an efficient capture of the carriers by the QDs.
Institut d'Electronique, de Microélectronique et de Nanotechnologie, UMR 8520, Avenue Poincaré, B.P. 69, F-59652 Villeneuve d'Ascq Cedex, France. Arnaud.Devos@isen.fr
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Devos
F
F
Poinsotte
J
J
Groenen
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O
Dehaese
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N
Bertru
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Ponchet