The transition from ripples to islands in strained heteroepitaxial growth under low driving forces

We investigate the morphological evolution during the growth of strained GexSi1-x layers from In solution (5 less than or equal to x less than or equal to 15%). Surface ripples develop due to elastic stress relaxation. These ripples self-organize in a way that a defined wavelength and a two-dimensional pattern aligned along (1 0 0) directions develops. During further growth, the ripples transform into pseudomorphic islands and island growth proceeds in vertical direction at constant island width. The ripple wavelength and the island size are controlled by the germanium content and verify energetical predictions. Further, the theoretical expectation is corroborated that island development occurs even al low misfits when deposition is controlled by energetics. (C) 1998 Elsevier Science B.V. All rights reserved.