A transmission electron microscopic and optical study was made of GaN dots which were embedded in an AlN matrix. The dots were grown, by using molecular beam epitaxy, on top of an AlN layer on (00•1) sapphire. It was found that the GaN dots, with an average diameter of 16nm and an average height of 4nm, grew coherently on AlN but nucleated next to threading edge dislocations that were propagating in the AlN. The presence of these adjacent dislocations did not inhibit the optical emission of the dots.

Preferential Nucleation of GaN Quantum Dots at the Edge of AlN Threading Dislocations J.L.Rouvière, J.Simon, N.Pelekanos, B.Daudin, G.Feulliet: Applied Physics Letters, 1999, 75[17], 2632-4