Dephasing of excitons and multiexcitons in undoped and p-doped InAs/GaAs quantum dots-in-a-well

Cesari, Valentina, Langbein, Wolfgang Werner ORCID: https://orcid.org/0000-0001-9786-1023 and Borri, Paola ORCID: https://orcid.org/0000-0002-7873-3314 2010. Dephasing of excitons and multiexcitons in undoped and p-doped InAs/GaAs quantum dots-in-a-well. Physical Review B 82 (19) , 195314. 10.1103/PhysRevB.82.195314

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Abstract

We report an experimental investigation of the dephasing of excitons and multiexcitons in technologically relevant undoped and p-doped InAs/GaAs dot-in-a-well structures emitting near 1.3 μm wavelength. Using a transient four-wave mixing technique in heterodyne detection, we measured the excitonic dephasing due to phonon coupling in the temperature range from 5 to 300 K, and the multiexcitonic dephasing at low temperature by electrically injecting carriers through a p-i-n diode structure. While the temperature-dependent excitonic dephasing is found to be similar to previous studies, the contribution from electrically injected carriers is weaker in these dot-in-a-well systems due to a reduced pure dephasing from Coulomb interaction with carriers in the barrier material. Moreover, multiexcitonic transitions contribute with a subpicosecond dephasing, corresponding to a homogeneous broadening in the meV range. In the p-doped structure, positively charged multiexcitons are formed due to the built-in hole reservoir, which show a dominating dephasing component in the subpicosecond range. However, a weaker component in the 10 ps range is observed and attributed to final states with spin-forbidden relaxation.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Schools > Biosciences Schools > Physics and Astronomy
Subjects:	Q Science > Q Science (General) Q Science > QC Physics
Additional Information:	9 pp.
Publisher:	American Physical Society
ISSN:	1098-0121
Funders:	EPSRC
Last Modified:	12 May 2023 16:34
URI:	https://orca.cardiff.ac.uk/id/eprint/22818

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