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Title: Anomalous spectral dependence of optical polarization and its impact on spin detection in InGaAs/GaAs quantum dots

We show that circularly polarized emission light from InGaAs/GaAs quantum dot (QD) ensembles under optical spin injection from an adjacent GaAs layer can switch its helicity depending on emission wavelengths and optical excitation density. We attribute this anomalous behavior to simultaneous contributions from both positive and negative trions and a lower number of photo-excited holes than electrons being injected into the QDs due to trapping of holes at ionized acceptors and a lower hole mobility. Our results call for caution in reading out electron spin polarization by optical polarization of the QD ensembles and also provide a guideline in improving efficiency of spin light emitting devices that utilize QDs.
Authors:
; ; ;  [1] ; ; ; ;  [2]
  1. Department of Physics, Chemistry and Biology, Linköping University, S-581 83 Linköping (Sweden)
  2. Graduate School of Information Science and Technology, Hokkaido University, Kita 14, Nishi 9, Kita-ku, Sapporo 060-0814 (Japan)
Publication Date:
OSTI Identifier:
22350800
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 105; Journal Issue: 13; 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; DETECTION; EMISSION; EXCITATION; GALLIUM ARSENIDES; HOLE MOBILITY; HOLES; INDIUM ARSENIDES; INJECTION; LAYERS; LIGHT EMITTING DIODES; POLARIZATION; QUANTUM DOTS; READOUT SYSTEMS; SPIN; SPIN ORIENTATION; TRAPPING; VISIBLE RADIATION; WAVELENGTHS