Critical thicknesses of 2D to 3D growth and morphological 'hut'-'dome' cluster transitions in Ge layers were measured. In comparison with the growth on the pure Si(100) surface, a decrease in the critical thicknesses of 2D-3D and hut-dome transitions was observed and accounted for by the accumulation of elastic strains as Ge content or thickness of the GeSi solid solution increased. The density and size of Ge nanoclusters were determined depending on the solid solution composition. The presence of a thin strained layer of the GeSi solid solution caused not only the changes in critical thicknesses of the transitions, but also affected the properties of the germanium nanocluster array. (C) 2011 Elsevier B. V. All rights reserved.