Intrinsic electric field effects on few-particle interactions in coupled GaN quantum dots

We study the multiexciton optical spectrum of vertically coupled GaN∕AlN quantum dots with a realistic three-dimensional direct-diagonalization approach for the description of few-particle Coulomb-correlated states. We present a detailed analysis of the fundamental properties of few-particle∕exciton interactions peculiar of nitride materials. The giant intrinsic electric fields and the high electron∕hole effective masses give rise to different effects compared to GaAs-based quantum dots: intrinsic exciton-exciton coupling, nonmolecular character of coupled dot exciton wave function, strong dependence of the oscillator strength on the dot height, large ground-state energy shift for dots separated by different barriers. Some of these effects make GaN∕AlN quantum dots interesting candidates in quantum information processing.