We have studied the spin dynamics in self-organized InAs/GaAs quantum dots by time-resolved photoluminescence performed under strictly resonant excitation. At low temperature, we observe strictly no decay of both the linear and the circular luminescence polarization. This demonstrates that the carrier spins are totally frozen on the exciton lifetime scale.

Stacked InAs quantum dots (QDs) grown on InP(113)B are analyzed both experimentally and theoretically in order to study the influence of the electronic vertical coupling between the QD layers. Improved growth conditions enable us to control the optimum QD height of the samples, thus yielding an emission wavelength of our nanostructures at about 1.55μm at room temperature. Three samples containing three QD layers with different vertical spacing are studied. The QD electronic structure is studied by continuous-wave photoluminescence and time-resolved photoluminescence experiments at low temperature. A simplified theoretical model is developed, yielding results consistent with experimental data. This analysis evidences the electronic coupling between the QD layers.

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