Non-conventional GaAs/GaAlAs structures, with an AlAs monolayer inserted at different positions in wells, have been investigated to observe the behaviour of excitons in quantum wells. The energy and the oscillator strength for different transitions are calculated as a function of the probe position. The differential reflectivity of the spectrum for some samples is measured in order to test our theoretical simulations. We confirmed the observation of certain parity-forbidden transitions only in the most asymmetric samples.

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Due to a regrettable technical error some Greek and special letters in the paper were not reproduced. Please, find here the fully corrected article.In pump-probe experiments, we measured the anisotropic exchange energy splitting of the low-lying electron-hole pair states in an ensemble of as-grown InAs/GaAs self-assembled quantum dots. This splitting shows a monotonic decrease with the energy of interband emission. We discuss this result considering different parameters: shape anisotropy, wavefunction confinement, size of the quantum dots, and piezoelectric effect.

International audienceIn pump-probe experiments, we measured the anisotropic exchange energy splitting of the low-lying electron-hole pair states in an ensemble of as-grown InAs/GaAs self-assembled quantum dots. This splitting shows a monotonic decrease with the energy of interband emission. We discuss this result considering different parameters: shape anisotropy, wavefunction confinement, size of the quantum dots, and piezoelectric effect. (c) 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

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