In situ detection of an initial elastic relaxation stage during growth of In0.2Ga0.8As on GaAs(0 0 1)

We have followed, in situ and real-time, both the relaxation and morphological evolution along [1 1 0] direction during the growth of In0.2Ga0.8As/GaAs by molecular beam epitaxy (MBE) at low growth rates (0.2 and 0.5 monolayers per second, i.e. ML/s). The stress measurements were performed by optical monitorization of the strain-induced substrate curvature, and the morphology evolution was assessed by means of laser light scattering (LLS). The correlation of the real-time results obtained from both in situ techniques allowed us to detect the existence of a growth rate dependent initial elastic relaxation regime, which is associated with the development of a long-range ordered rippled-like morphology along [1 -^1 0] direction.