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Proceedings Paper

Carrier distribution, spontaneous emission, and gain in self-assembled quantum dot lasers
Author(s): Peter M. Smowton; Emma J. Pearce; Julie Lutti; Daniel R. Matthews; Huw D. Summers; Gareth M. Lewis; Peter Blood; Mark Hopkinson; Andrey Krysa
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Paper Abstract

We examine the mechanisms that lead to a low value of saturated modal gain in both 1μm emitting InGaAs based and ≈ 700nm emitting InP/GaInP quantum dot laser systems. We explain the observation that the value of the saturated modal gain increases as the temperature decreases using a simple model of the filling of the available dot and wetting layer states according to a Fermi-Dirac distribution. We show that it is the relatively large number of available wetting layer valence states and their proximity in energy to the dot states that limits the modal gain. We measure the population inversion factor for samples containing different numbers of layers of dots and for samples where the dots are grown in a quantum well (DWELL) and for dots grown in bulk layers of either GaAs or Al0.15Ga0.85As (non-DWELL). Comparison of this data with that calculated for a Fermi-Dirac distribution of carriers in the available states demonstrates that for most of the samples the carriers in the ground states of the quantum dots are not in thermal equilibrium with those in higher lying energy states - the excited states or wetting layer.

Paper Details

Date Published: 11 May 2004
PDF: 10 pages
Proc. SPIE 5365, Novel In-Plane Semiconductor Lasers III, (11 May 2004); doi: 10.1117/12.530429
Show Author Affiliations
Peter M. Smowton, Cardiff Univ. (United Kingdom)
Emma J. Pearce, Cardiff Univ. (United Kingdom)
Julie Lutti, Cardiff Univ. (United Kingdom)
Daniel R. Matthews, Cardiff Univ. (United Kingdom)
Huw D. Summers, Cardiff Univ. (United Kingdom)
Gareth M. Lewis, Cardiff Univ. (United Kingdom)
Peter Blood, Cardiff Univ. (United Kingdom)
Mark Hopkinson, Univ. of Sheffield (United Kingdom)
Andrey Krysa, Univ. of Sheffield (United Kingdom)

Published in SPIE Proceedings Vol. 5365:
Novel In-Plane Semiconductor Lasers III
Claire F. Gmachl; David P. Bour, Editor(s)

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