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A carrier relaxation bottleneck probed in single InGaAs quantum dots using integrated superconducting single photon detectors

Authors :
Reithmaier, G.
Flassig, F.
Hasch, P.
Lichtmannecker, S.
Müller, K.
Vuckovic, J.
Gross, R.
Kaniber, M.
Finley, J. J.
Source :
Appl. Phys. Lett. 105, 081107 (2014)
Publication Year :
2014

Abstract

Using integrated superconducting single photon detectors we probe ultra-slow exciton capture and relaxation dynamics in single self-assembled InGaAs quantum dots embedded in a GaAs ridge waveguide. Time-resolved luminescence measurements performed with on- and off-chip detection reveal a continuous decrease in the carrier relaxation time from 1.22 $\pm$ 0.07 ns to 0.10 $\pm$ 0.07 ns upon increasing the number of non-resonantly injected carriers. By comparing off-chip time-resolved spectroscopy with spectrally integrated on-chip measurements we identify the observed dynamics in the rise time ($\tau_r$) as arising from a relaxation bottleneck at low excitation levels. From the comparison with the temporal dynamics of the single exciton transition with the on-chip emission signal, we conclude that the relaxation bottleneck is circumvented by the presence of charge carriers occupying states in the bulk material and the two-dimensional wetting layer continuum. A characteristic -2/3 power law dependence of the rise time is observed suggesting Auger-type scattering between carriers trapped in the quantum dot and the two-dimensional wetting layer continuum which circumvents the phonon relaxation bottleneck.

Details

Database :
arXiv
Journal :
Appl. Phys. Lett. 105, 081107 (2014)
Publication Type :
Report
Accession number :
edsarx.1407.0593
Document Type :
Working Paper
Full Text :
https://doi.org/10.1063/1.4894239