Microscopic tight-binding description for electronic and optical properties of InN/GaN quantum dots

Electronic and optical properties of self-assembled InN/GaN quantum dots are investigated by use of a tight-binding model combined with a configuration interaction calculation. Dipole and Coulomb matrix elements are calculated from the single-particle wavefunctions which fully include the atomistic wurtzite structure of the low-dimensional heterostructure and serve as input parameters for the calculation of optical properties. We discuss in particular the influence of the internal electric field on the multi-exciton spectra. Dark exciton and biexciton ground-states are found for small quantum dots.