On the onset of InAs islanding on InP: influence of surface steps

We investigate the transition from two- to three-dimensional growth of thin InAs films on InP by chemical beam epitaxy. This transition is shown to strongly depend on growth temperature and on the misorientation-or the presence of surface steps - on the InP surface where the InAs film is deposited. Low temperature photoluminescence measurements on InP-InAs-InP quantum well structures and atomic force microscopy analysis of InAs-InP structures indicate different islanding behaviors for substrates with different misorientations, the onset of islanding process occurring earlier for misoriented than for nominal substrates. The shape and distribution of the islands indicate the existence of a step edge barrier altering the diffusion dynamics on the surface. Low growth temperature is shown to delay islanding for a fixed deposition time and also limit island formation to certain regions of the sample where smooth corrugations (slope similar to 1 degrees) are observed. (C) 1997 Elsevier Science B.V.