Photoluminescence competition between confined states in delta doped AlGaAs/GaAs heterostructures

H. Ajlani1*, A. Meftah1, S. Aloulou1, R. Chtourou2, M. Oueslati1

1Unité de Recherche de Spectroscopie Raman, Département de Physique, Faculté des Sciences

de Tunis, 1060 Le Belvédère, Tunis, Tunisie

2 Institut National de Recherche Scientifique et Technique, Tunis.

* Corresponding author. E-mail: hosniajl@yahoo.com

Received: 05 April 2005; revised version accepted: 30 May 2005

Abstract

Low temperature photoluminescence (PL) studies in n-type modulation doped GaAs/Al0.31Ga0.69As/GaAs:d Si/Al0.31Ga0.69As/GaAs heterostructures show a large asymmetric band located at energies higher than band-to-band radiative recombination energies in GaAs. We have combined experimental and theoretical modeling of the band structure and have shown that this band corresponds to radiative recombination of confined excitons in both asymmetric quantum well (AQW) in the GaAs channel and symmetric quantum well (SQW) in the barrier. The characteristics and the shape of the considered band have been studied as a function of excitation density and temperature.

Keywords: Photoluminescence; AlGaAs; GaAs; Heterostructure; Quantum well.

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