Anisotropic growth processes on gaas(Loo) and ge(100)

We have used reflection high energy electron diffraction (RHEED) to follow the growth of GaAs on misoriented GaAs(100), using molecular beam epitaxy (MBE). We find anisotropies in the step order, kink density and the growth oscillations as a function of substrate misorientation and direction of surface misorientation. For comparison in a simple system, growth of Ge on Ge(100) is also followed. On the singular Ge(100) surface, we observe strong RHEED oscillations accompanied by a strong anisotropy in the nucleation of the islands during growth. These islands show up as long intersecting streaks in the diffraction pattern when the electron beam is incident along the [010] direction. In the presence of AS₄, these anisotropic features become more striking and stronger RHEED oscillations are observed over a wider temperature range.