Thin films of InAlN, grown onto GaN/Al2O3 (00•1) templates by metal-organic vapour phase epitaxy, were studied using transmission electron microscopy. V-defects in the form of hexagonal inverted pyramids with {10•1} side-walls were observed on the film surfaces; linked to the terminations of threading dislocations. Their origin was attributed to the differing surface-mobilities of In and Al, and to the built-in strain relaxation. The segregation of In in the films was influenced by the formation of V-defects; whose edges and apices acted as paths of migrating In atoms, diffusing along nanopipes formed at the open-core threading dislocations.

Indium Migration Paths in V-Defects of InAlN Grown by Metal-Organic Vapor Phase Epitaxy. T.Kehagias, G.P.Dimitrakopulos, J.Kioseoglou, H.Kirmse, C.Giesen, M.Heuken, A.Georgakilas, W.Neumann, T.Karakostas, P.Komninou: Applied Physics Letters, 2009, 95[7], 071905