It was recalled that, during the early stages of molecular beam epitaxial GaAs growth onto an (001) Si substrate, very small GaAs islands were formed in which the crystal lattices were coherent, or partially coherent, with the substrate. These initial semi-coherent islands were studied here. The use of high-resolution electron microscopy, together with multi-slice and elasticity calculations, led to the conclusion that interfacial stair-rod dislocations were present which formed V-shaped defects. Each of the latter was thought to involve 2 intrinsic, or 2 extrinsic, stacking faults which extended towards the GaAs side. It was found that these defects were stair-rod dislocations that partially relieved the 4% misfit. They were connected to 2 intrinsic stacking faults, and had a Burgers vector of 1/6[1¯10], or were connected to 2 extrinsic stacking faults, and had a Burgers vector of 1/3[1¯10].

M.Loubradou, R.Bonnet, A.Vila, P.Ruterana: Materials Science Forum, 1996, 207-209, 285-8