Electronic properties of InGaAs/GaAs strained coupled quantum dots modeled by eight-band k · p theory

Electronic properties of InGaAs/GaAs strained coupled quantum dots (QDs) are investigated using the eight-band model as a function of structural parameters such as strain (or the indium composition), the radius of QD, the height of QD, and the distance between the QDs. For the conduction band, the eight-band model shows a significantly larger ground state energy than the four- or six-band model. In the case of the hole, the differences of the ground state energy between these models are less significant than those for the conduction band states. In the case of the QD with a small height l, it is shown that the transition energies are nearly independent of models. However, with increasing l, the eight-band model gives results different from those of the four- or six-band model and the difference of the transition energy between models increases gradually. Similar results are also observed for the QD radius dependence of the transition energy. The transition energy increases with the distance d between two adjacent dots in the z direction while the transition energy is a weak function of the lateral dot spacing L - 2R along the x and y directions.