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

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 ± 0.07 ns to 0.10 ± 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 (τ{sub 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 τ{sub r} ∝ P{sup −2∕3} power law dependence 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.
Authors:
; ; ; ;  [1] ;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [1] ;  [6]
  1. Walter Schottky Institut, Technische Universität München (Germany)
  2. (United States)
  3. E. L. Ginzton Laboratory, Stanford University, Stanford, California 94305 (United States)
  4. (Germany)
  5. Walther Meißner Institut, Bayerische Akademie der Wissenschaften, Garching (Germany)
  6. (NIM), Schellingstraße 4, 80799 München (Germany)
Publication Date:
OSTI Identifier:
22310934
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CAPTURE; CARRIERS; CHARGE CARRIERS; DETECTION; EXCITATION; GALLIUM ARSENIDES; INDIUM COMPOUNDS; LAYERS; LUMINESCENCE; PHOTODETECTORS; PHOTONS; QUANTUM DOTS; RELAXATION TIME; SCATTERING; SPECTROSCOPY; SUPERCONDUCTING DEVICES; TIME RESOLUTION; TRAPPING; TWO-DIMENSIONAL CALCULATIONS