Influence of Supersaturation on Surface Structure

Abstract

Using low-energy electron microscopy, we have investigated the influence of an external flux on the structure of the Si(111) surface during growth and etching at elevated temperatures. We find that varying the adatom supersaturation effectively changes the surface free energies of coexisting [Formula presented] and ’[Formula presented]’ regions of the surface. In response, the boundaries separating the phases adopt a new steady-state configuration. The measured configuration can be used to quantitatively determine the difference in free energy between the phases, [Formula presented]. The change in [Formula presented] provides a measure of the local supersaturation at the surface, and can be interpreted as a change in the phase-transition temperature. © 2002 The American Physical Society.