Simulation evidence for lateral excitation transfer in a self-assembled quantum-dot array

Simulations of InAlAs/AlGaAs self-assembled quantum-dot arrays containing as many as 30 individual dots are used to identify a mechanism for lateral excitation transfer through partially delocalized heavy-hole states. Individual hole states exhibit wave-function splitting between several dots in the array, as well as partial confinement in the wetting layer, and have strong overlap with multiple conduction-band electron states in different quantum dots. Electron–hole pair energies involving these partially delocalized hole states correspond well with narrow resonances seen in the experimental photoluminescence excitation spectra taken for similar quantum-dot arrays using low-temperature near-field scanning optical microscopy.