Nonpolar GaN quantum dots: Impact of dot size and shape on the electron and hole wave function overlap

In this work we analyze the spatial overlap of electron and hole ground state wave functions in a-plane GaN/AlN quantum dots. Special attention is paid to the impact of the quantum dot geometry, when taking Coulomb effects into account. Our analysis shows, comparing systems with almost identical volumes, that the shape of the quantum dot base is more important than the dimension of the dot along the c-axis. This initially surprising result is related to the change of the potential profile inside the nanostructure. Furthermore, our analysis confirms that Coulomb effects play an important role when describing the optical properties of nonpolar nitride-based QD structures.