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This work aims to investigate the effects of magnetic field strength and direction on the electronic properties and optical response of GaAs/AlGaAs-based heterostructures. An investigation of the excitonic spin-splitting of a disordered multiple quantum well embedded in a wide parabolic quantum well is presented. The results for polarization-resolved photoluminescence show that the magnetic field dependencies of the excitonic spin-splitting and photoluminescence linewidth are crucially sensitive to magnetic field orientation. Our experimental results are in good agreement with the calculated Zeeman splitting obtained by the Luttinger model, which predicts a hybridization of the spin character of states in the valence band under tilted magnetic fields.

The effects of temperature on the optical properties of lattice matched InGaAs/InP superlattices are reported. We found that the PL spectra are dominated by the recombination of carriers in the lowest energy minibands formed by – and –X. Effects of temperature on the contribution of each of these minibands are analyzed using two distinct models, proposed by Varshni and Vina. The Debye temperature of the material was estimated to be 356 K and small values of the Varshni parameter α demonstrated that InGaAs/InP superlattices are an attractive system for high operating temperature devices. Additionally, the fit of experimental data by Vina's model provided an estimate of the strength of the exciton-average phonon.

The photoluminescence from individual quantum wells of artificially disordered weakly coupled multi-layers embedded in wide AlGaAs parabolic wells was investigated in a strong magnetic field. We show that the response of the individual wells is very different from the average response of the multi-layers studied by transport measurements and that photoluminescence represents a local probe of the quantum Hall state formed in three-dimensional electron system. The observed magnetic field induced variations of the in-layer electron density demonstrate the formation of a new phase in the quasi-three-dimensional electron system. The sudden change in the local electron density found at the Landau filling factor ν=1 by both the magneto-transport and the magneto-photoluminescence measurements was assigned to the quantum phase transition.