A detailed transmission electron microscopy study was first made of dislocation networks formed at shallow buried interfaces obtained by bonding two GaAs crystals, between which a twist and a tilt around a <110> direction were established in a controlled manner. For large enough twists, the dislocation networks consisted of a 2-dimensional network of screw dislocations accommodating mainly the twist and a 1-dimensional network of mixed dislocations accommodating mainly the tilt. It was shown that, in addition, the mixed dislocations accommodated part of the twist and slight unexpected misorientations of the screw dislocations with respect to the <110> directions were observed and explained. By performing a quantitative analysis of the whole dislocation network, a coherent interpretation of these observations was proposed which also provided data inaccessible by direct experiment. When the twist was small enough, one screw sub-network vanishes. The surface strain field induced by such dislocation networks was used to pilot the lateral ordering of GaAs and InGaAs nanostructures during metal-organic vapor phase epitaxy. It was proved that the dimensions and orientations of the nanostructures were correlated with those of the cells of the underlying dislocation network and explained how the interface dislocation structure governs the formation of the nanostructures.

Buried Dislocation Networks Designed to Organize the Growth of III-V Semiconductor Nanostructures. J.Coelho, G.Patriarche, F.Glas, G.Saint-Girons, I.Sagnes, L.Largeau: Physical Review B, 2004, 70[15], 155329 (11pp)