A quantum dot nucleated on the edge of a threading dislocation: elastic and electric field effects

In this work the affect of a threading dislocation localised on the edge of GaN/AlN quantum dot is analysed. A standard piezoelectric continuum model is extended to allow the embodiment of threading dislocations that are modelled as a continuous electro-elastic line defect originating in the matrix material. Two common types of dislocation are considered: an edge-type and a screw-type. It is demonstrated that the presence of a TD provides local region of tensile strain as a preferential condition for GaN QD growth by reduction of the GaN/AlN lattice mismatch. It is found that dislocation induced potential causes a measurable in-plane shift of the electron/hole localisation and an asymmetric decrease in the band-toband transition energy. (C) 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim