NATURE OF OPTICAL-TRANSITIONS IN SELF-ORGANIZED INAS GAAS QUANTUM DOTS/

Electronic transitions in nm-scale pyramid-shaped InAs/GaAs quantum do ts feature only ground-state electrons. Allowed optical transitions in volving excited hole states in addition to the ground-state transition are revealed in absorption and photoluminescence spectra. The experim ental data agree with detailed theoretical calculations of the electro nic structure, including strain, piezoelectric, and excitonic effects, and lead to unambiguous assignment of the transitions. We find as upp er bound for the relative standard deviation of the size fluctuation x i less than or equal to 0.04. The hole sublevel separation is consiste nt with a pyramid shape fluctuation between {101} and {203} side facet s.