Substrate orientation dependence of island nucleation critical thickness in strained heterostructures

The two-dimensional to three-dimensional transition in highly strained InAs grown on high index (N11) GaAs substrates was investigated. The samples were characterised by photoluminescence measurements and atomic force microscopy. Controlled changes in the 2D/3D growth critical thickness have been observed by changing the substrate orientation. The results have been interpreted by means of an equilibrium model which takes into account the effects of substrate orientation. In-island strain relaxation, affected in a controlled way by substrate orientation, is found to play the major role in determining the critical thickness value.