Strongly temperature-dependent recombination kinetics of a negatively charged exciton in asymmetric quantum dots at 1.55 µm

Ł. Dusanowski, M. Gawełczyk, J. Misiewicz, S. Höfling, J. P. Reithmaier, G. Sęk

Research output: Contribution to journalArticlepeer-review

Abstract

We report on strongly temperature-dependent kinetics of negatively charged carrier complexes in asymmetric InAs/AlGaInAs/InP quantum dots (dashes) emitting at telecom wavelengths. The structures are highly elongated and of large volume, which results in atypical carrier confinement characteristics with s-p shell energy splittings far below the optical phonon energy, which strongly affects the phonon-assisted relaxation. Probing the emission kinetics with time-resolved microphotoluminescence from a single dot, we observe a strongly non-monotonic temperature dependence of the charged exciton lifetime. Using a kinetic rate-equation model, we find that a relaxation side-path through the excited charged exciton triplet states may lead to such behavior. This, however, involves efficient singlet-triplet relaxation via the electron spin-flip. Thus, we interpret the results as an indirect observation of strongly enhanced electron spin relaxation without a magnetic field, possibly resulting from atypical confinement characteristics.
Original languageEnglish
Article number043103
Number of pages5
JournalApplied Physics Letters
Volume113
Issue number4
DOIs
Publication statusPublished - 23 Jul 2018

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