The effects of adjacent dislocations on the electronic and optical properties of GaN/AlN quantum dots

We present a theory of the electronic energy levels and wave functions within GaN quantum dots (QDs), including the effect of the strain field of a nearby dislocation and a full treatment of the built-in electrostatic potential. The QD carrier spectra and wave functions are calculated using a plane-wave expansion method within an 8-band View the MathML source model. The GaN QDs are truncated hexagonal pyramids on a wetting layer with an edge dislocation adjacent to each dot. The built-in piezoelectric potential strongly influences the localization of the carrier wave functions. The potential pushes the electrons to the top of the dot, the holes to the bottom and, additionally, causes strong lateral confinement of the carriers near the dot center. The strong lateral confinement of the carriers indicates that the effect of the strain field due to the dislocation is relatively small. The size of the dot influences the energies and overlaps, but the presence of the dislocation has minimal effect. The dependence of the ground state optical transition energy on the size of the dot is in good agreement with experimental data.