Transient luminescence of dense InAs/GaAs quantum dot arrays

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

Yu.I. Mazur
Department of Physics, University of Arkansas, Fayetteville, Arkansas 72701

H. Kissel
Ferdinand-Braun-Institut für Höchstfrequenztechnik, Albert-Einstein-Strasse 11, D-12489 Berlin, Germany

G.G. Tarasov, Z.Ya. Zhuchenko, and W.T. Masselink
Department of Physics, Humboldt-Universität zu Berlin, Invalidenstr. 110, D-10115 Berlin, Germany

Published in:
Physical Review B 67 (4), 045326 (2003).
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Abstract:
Carrier transfer between quantum dots (QDs) in very dense InAs/GaAs QD arrays is studied by means of steady state and time-resolved photoluminescence spanning a wide range of laser power from 10⁹ to 10¹³ photons/(pulse x cm²). Carrier transfer involves transitions from the ground state of small QDs into lower lying states of larger QDs, a relaxation channel that saturates at high excitation densities. The transition from saturation of the interdot carrier transfer to the unsaturated regime is identified by analyzing the temporal shape of the luminescence signal for decreasing excitation densities. The rate equation model is proposed to account the temporal evolution of photoluminescence in dense QD systems. Numerical simulations of the carrier transfer and relaxation including the interdot coupling are in good agreement with the experimental results.

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