Growth of strained Ga1-xInxP layers on GaP(001) by gas source molecular beam epitaxy: comparison with the GaInAs/GaAs system

Using Reflexion High Energy Electron Diffraction, Atomic Force Microscopy and Double Crystal X-ray Diffraction, the growth of Ga_1-xIn_xP alloys on GaP (001) with x varying from 0.2 to 1 (InP) is investigated and compared to that of InGaAs alloys on GaAs (001). At 520°C, the transition from the relaxation mode via misfit dislocation generation to that via 3D growth occurs at lower x in the phosphide case (0.2) than in the arsenide one (0.25), For x<0.5, 3D growth leads to the development of wire-like structures along the [110] direction which can be related to recent results on the phosphide surface reconstructions. Finally, for the growth of InP on GaP at 520°C, the critical thickness is 2.1 MLs and we observe a small density of very large islands, in contrast to the InAs/GaAs case, At 400°C, the critical thickness decreases (1.7 MLs) as well as the island mean size whereas the density increases. We discuss this behavior in terms of surface energy