Molecular-beam epitaxy of InxGa1–xN alloy on GaN(00▪1) was investigated by scanning tunneling microscopy. The Stranski-Krastanov mode of growth of the alloy was followed, where the newly nucleated three-dimensional islands were initially coherent to the underlying GaN and the wetting layer, but then became dislocated when grown bigger than about 20nm in the lateral dimension. Two types of islands showed different shapes, where the coherent ones were cone shaped and the dislocated ones were pillar like, having flat-tops. Within a certain range of material coverage, the surface contained both coherent and dislocated islands, showing an overall bimodal island-size distribution. The continued deposition on such surfaces led to the pronounced growth of dislocated islands, whereas the sizes of the coherent islands change very little.

Coherent and Dislocated Three-Dimensional Islands of InxGa1–xN Self-Assembled on GaN(0001) During Molecular Beam Epitaxy. Y.Liu, Y.G.Cao, H.S.Wu, M.H.Xie, S.Y.Tong: Physical Review B, 2005, 71[15], 153406 (4pp)