On the period of reflection high-energy electron diffraction intensity oscillations during Si molecular-beam epitaxy on vicinal Si(001)

Abstract

We report the observation of reflection high-energy electron diffraction intensity oscillations with a period different from an integer number of atomic layers. These oscillations, which arise from the periodic nucleation, growth, and coalescence of two-dimensional islands, are recorded during Si molecular-beam epitaxial (MBE) growth on vicinal Si(001) at growth conditions near step flow. We explain the deviation of the period from an integer number of atomic layers by the diffusive loss of Si atoms from the terraces where the islands grow to the surface steps. This explanation will be elucidated by comparison with Monte Carlo computer simulations of Si MBE.