Ensemble interactions in strained semiconductor quantum dots

Large variations in InxGa1-xAs quantum dot concentrations were obtained wit h simultaneous growths on vicinal GaAs [001] substrates with different surf ace step densities. It was found that decreasing dot-dot separation blueshi fts all levels, narrows intersublevel transition energies, shortens lumines cence decay times for excited states, and increases inhomogeneous photolumi nescence broadening. These changes in optical properties are attributed to a progressive strain deformation of the confining potentials and to the inc reasing effects of positional disorder in denser dot ensembles.