On three dimensional self-organization and optical properties of InAs quantum-dot multilayers

We report on experiments aimed at producing three-dimensional self-organiza tion in InAs quantum-dot multilayers embedded in GaAs. These InAs/GaAs quan tum-dot multilayers have been grown by molecular beam epitaxy. Employing at omic force microscopy, we have analyzed the island density in samples with different number of periods of InAs/GaAs bilayers The results reveals a dec rease and a tendency to saturation of the island density with an increase i n the number of periods, as a three-dimensional self-organization character istic of these samples. Optical properties of the samples are examined via photoluminescence spectroscopy. The evolution of the quantum-dot photolumin escence peak position indicates an increment in the mean size of the buried islands and a relative homogenization in size of the quantum dots, as the number of periods increases. The results of the optical measurements agree with the morphological data, and characterize a spatial process of self-org anization, related to the increment of the number of periods in the multila yers. (C) 2000 American Institute of Physics. [S0003-6951(00)03623-8].