Exciton dephasing via phonon interactions in InAs quantum dots: dependence on quantum confinement

Borri, Paola ORCID: https://orcid.org/0000-0002-7873-3314, Langbein, Wolfgang Werner ORCID: https://orcid.org/0000-0001-9786-1023, Woggon, U., Stavarache, V., Reuter, D. and Wieck, A. D. 2005. Exciton dephasing via phonon interactions in InAs quantum dots: dependence on quantum confinement. Physical Review B: Condensed Matter and Materials Physics 71 (11) , 115328. 10.1103/PhysRevB.71.115328

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Abstract

We report systematic measurements of the dephasing of the excitonic ground-state transition in a series of InGaAs?GaAs quantum dots having different quantum confinement potentials. Using a highly sensitive four-wave mixing technique, we measure the polarization decay in the temperature range from 5 to 120 K on nine samples having the energy distance from the dot ground-state transition to the wetting layer continuum (confinement energy) tuned from 332 to 69 meV by thermal annealing. The width and the weight of the zero-phonon line in the homogeneous line shape are inferred from the measured polarization decay and are discussed within the framework of recent theoretical models of the exciton-acoustic phonon interaction in quantum dots. The weight of the zero-phonon line is found to decrease with increasing lattice temperature and confinement energy, consistently with theoretical predictions by the independent Boson model. The temperature-dependent width of the zero-phonon line is well reproduced by a thermally activated behavior having two constant activation energies of 6 and 28 meV, independent of confinement energy. Only the coefficient to the 6-meV activation energy shows a systematic increase with increasing confinement energy. These findings rule out that the process of one-phonon absorption from the excitonic ground state into higher energy states is the underlying dephasing mechanism.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Biosciences Physics and Astronomy
Subjects:	Q Science > QC Physics
Publisher:	American Physical Society
ISSN:	1098-0121
Last Modified:	10 May 2023 20:34
URI:	https://orca.cardiff.ac.uk/id/eprint/1541

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