Abstract
In this work we report a theoretical study of excitons behavior in self-assembled strain-free GaAs quantum dot molecules (QDMs) obtained by nanoholes filling. More precisely, we study a single molecule formed by a vertically coupled GaAs/AlGaAs quantum dots pair (QDP). The vertical coupling governed by varying the spacer thickness layer reveals how the excitons behave in a QDM. A model based on resolving the three-dimensional effective-mass Schrodinger equation is adopted to reliably provide a complete overview of the fine structure of neutral and complexes excitons and to explain how a pair of quantum dots interact in between while varying the spacer layer thickness mediating the coupling in the barrier. Our calculations can be adopted to improve the growth conditions and boost the optical properties of strain-free GaAs QDMs for using them in quantum information technologies and quantum computing.