Two stages of post-growth recovery in molecular beam epitaxy: a surface X-ray diffraction study

We study the kinetics of the GaAs(0 0 1) surface during and after homoepitaxial deposition of GaAs by in situ surface X-ray diffraction. Two stages of recovery are recognized and quantitatively described with kinematical scattering theory. In the first, fast stage of recovery, adatom islands and advacancy islands (pits) on adjacent layers annihilate, giving rise to a surface with only one incompletely filled layer. The second, slow stage of recovery is the coarsening of the remaining islands or pits. The experimental data are compared with Monte Carlo simulations of the deposition and recovery kinetics.