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

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 w...

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Bibliographic Details
Published in:Applied physics letters 2018-07, Vol.113 (4)
Main Authors: Dusanowski, Ł., Gawełczyk, M., Misiewicz, J., Höfling, S., Reithmaier, J. P., Sęk, G.
Format: Article
Language:English
Subjects:
Applied physics
Confinement
Electron spin
Electrons
Elongated structure
Excitons
Kinetics
Magnetic induction
Quantum dots
Temperature dependence
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Summary: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.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.5030895