Electron and hole localization in coupled InP/InGaP self-assembled quantum dots

The electronic structure of vertically coupled (stacked) cylindrical InP/InGaP self-assembled quantum dots is calculated by the multiband effective mass theory. The nonuniform strain distribution is obtained through the valence force field method. The energy levels of stacks of three vertically coupled quantum dots are followed as they evolve from the ground state of the single quantum dot and split into triplets with decreasing dot distance. The holes are found to couple via the light hole states in the spacers between the dots. We found a reversal of the total angular momentum of the ground state of the hole from 3/2ℏ to 1/2ℏ with decreasing thickness of the spacer. The theoretical results are compared with recent photoluminescence measurements.