Vertical stacks of small InAs/GaAs self-assembled dots: resonant and non-resonant excitation

We have performed photoluminescence experiments in samples containing self-assembled quantum dots with different spacer layer thicknesses. A strong filtering effect produced by the GaAs spacer layer on the dots size being stacked is observed for spacers thinner than View the MathML source. This effect produces a blue shift of the emission band from stacked dots and a simultaneous line width narrowing. At the same time, given the existence of a broad dot size distribution in the first layer, bigger dots can evolve towards InAs cylinder-like structures, whose emission occurs at appreciably lower energies as compared to the emission band associated to dot stacks (with some GaAs separation).