Tight-binding model for semiconductor quantum dots with a wurtzite crystal structure: From one-particle properties to Coulomb correlations and optical spectra

In this work we investigate the electronic and optical properties of self-assembled quantum dots by means of a tight-binding model. Coulomb and dipole matrix elements are calculated from the one-particle wave functions which fully include the atomistic wurtzite structure of the low-dimensional heterostructures and serve as an input for the calculation of optical spectra. For the investigated InN GaN material system, the optical selection rules are found to be strongly affected by band-mixing effects for the localized valence band states. Within this framework, excitonic absorption and emission spectra are analyzed for different sizes of the investigated lens-shaped quantum dots, including the influence of the intrinsic and strain-induced electrostatic field of the wurtzite structure. A dark exciton ground state for small quantum dots is found.