Biexciton binding in quantum boxes

Abstract

In ultrasmall quantum nanostructures the interparticle Coulomb energy is a small perturbation to single-particle confinement and kinetic energies. Third-order perturbation theory has been used to calculate energies of excitons and biexcitons confined in quantum box nanostructures. The confined biexciton is more stable than two independent excitons in ultrasmall structures. The confinement-induced enhancement in biexciton binding should be negligible for boxes larger than several exciton diameters. Results are presented as a function of electron-hole mass ratio to develop a qualitative model of exciton-exciton interactions in zero-dimensional systems.