Surface Diffusion of Al Atoms on GaAs Vicinal Surfaces in Molecular Beam Epitaxy

We have studied the surface diffusion in molecular beam epitaxial growth of AlAs on GaAs vicinal surfaces by observing intensity oscillations of reflection high-energy electron diffraction (RHEED). By measuring the critical temperature where the RHEED oscillation begins to appear, the critical condition for the growth mode transition was determined. Combining the experimental results with the theory taking into account the surface diffusion and supersaturation ratio of adatoms on the terraces, the surface diffusion length of Al atoms is estimated and compared with that of GaAs.