The topologies and defect structures of interfaces, in strained layers that had been grown by molecular beam epitaxy, were investigated by means of transmission electron microscopy. The In fraction ranged from 0.16 to 1, and 3 critical layer thicknesses (corresponding to the formation of 3 different types of defect) were identified; with increasing thickness of the strained layers. These defects were interfacial topographies that resulted from the onset of 3-dimensional growth in the InGaAs layer, misfit dislocations of 60 mixed type, and dislocation complexes that consisted of planar defects on {111} planes. It was noted that both types of defect which involved dislocations resulted in a marked degradation of the optical properties of strained-layer structures.

J.Y.Yao, T.G.Andersson, G.L.Dunlop: Materials Science Forum, 1995, 189-190, 285-90