  In this paper we systematically analyze the electronic structures of polar
and nonpolar wurtzite-InN/GaN quantum dots and their modification due to the
quantum-confined Stark effect caused by intrinsic fields. This is achieved by
combining continuum elasticity theory with an empirical tight binding model to
describe the elastic and single-particle electronic properties in these nitride
systems. Based on these results, a many-body treatment is used to determine
optical absorption spectra. The efficiency of optical transitions depends on
the interplay between the Coulomb interaction and the quantum-confined Stark
effect. We introduce an effective confinement potential which represents the
electronic structure under the influence of the intrinsic polarization fields
and calculate the needed strength of Coulomb interaction to diminish the
separation of electrons and holes.
