Radiative lifetimes of spatially indirect excitons in type-II InAs/GaAsSb quantum dots

InAs/GaAsSb quantum dots (QDs) are recognized for their exceptional emission in the near-infrared spectrum, typically ranging from 1.28 to 1.6 mu m. These nanostructures hold significant promise for applications in fiberoptic communication, medical imaging, and environmental sensing systems. In this work, we theoretically investigated the effect of antimony composition on the emission properties of type-II InAs QDs embedded in GaAsSb barriers. First, we focus on the dependence of strain induced by lattice mismatch on charge carrier confinement profiles in InAs/GaA s 1- x Sb x /GaAs heterostructures ( x = 0.18, 0.24, and 0.28). Second, we discuss the influence of confinement potentials on the spatial distribution of charge carriers. We then calculate the electronic states as a function of antimony composition using an exact numerical diagonalization method. The ground-state exciton binding energy is estimated to below, around (similar or equal to 4 meV), for type-II QDs. Finally, the predicted values of the ground-state excitonic transition energy and the corresponding radiative lifetime of spatially indirect excitons structures are generally consistent with experimental results.