Built-in electric field effects on donor bound excitons in wurtzite InGaN strained coupled quantum dots

Considering the three-dimensional confinement of the electrons and holes and the strong built-in electric field induced by the spontaneous and piezoelectric polarizations of the wurtzite InxGa1−xN/GaN strained coupled quantum dots (QDs), the positively charged donor bound exciton binding energy is calculated within the framework of the effective-mass approximation and variational method. Our results clearly indicate that the donor bound exciton binding energy sensitively depends on the donor position in the system, the structural parameters of the coupled QDs and the strong built-in electric field. The variation of this energy versus the donor position is in several tens of meV.