Carrier dynamics in laterally strain-modulated InGaAs quantum wells

V. Talalaev, J.W. Tomm, and T. Elsaesser
Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2 A, 12489 Berlin, Germany

U. Zeimer, J. Fricke, A. Knauer, H. Kissel, and M. Weyers
Ferdinand-Braun-Institut für Höchstfrequenztechnik, Gustav-Kirchhoff-Strasse 4, 12489 Berlin, Germany

G.G. Tarasov
Institute of Semiconductor Physics, National Academy of Sciences, Prospect Nauki 45, 03028 Kiev, Ukraine

J. Grenzer and U. Pietsch
Institut für Physik, Universität Potsdam, Am Neuen Palais 10, 14469 Potsdam, Germany

Published in:
Applied Physics Letters 87, 262103 (2005).
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Abstract:
We investigate the transient recombination and transfer properties of nonequilibrium carriers in an In0.16Ga0.84As/GaAs quantum well (QW) with an additional lateral confinement implemented by a patterned stressor layer. The structure thus contains QW- and quantum-wire-like areas. At low excitation densities, photoluminescence (PL) transients from both areas are well described by a rate equation model for a three-level system with a saturable interlevel carrier transfer representing the lateral drift of carriers from the QW regions into the wires. Small-signal carrier lifetimes for QW, wires, and transfer time from QW to wire are 180, 190, and 28 ps, respectively. For high excitation densities the time constants of the observed transients increase, in agreement with the model. In addition, QW and wire PL lines merge indicating a smoothening of the potential difference, i.e., the effective carrier confinement caused by the stressor structure becomes weaker with increasing excitation.

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