Energetics of GaAs island formation on Si(100)

Abstract

It is proposed that GaAs island formation on Si(100) is thermodynamically driven by the stability of Si(100)2×1:As under As-rich conditions, and Si(100)2×1:(GaAs) under Ga-rich conditions. First-principles total-energy calculations indicate that thicker two-dimensional epitaxial GaAs films are higher in energy than these two structures provided the islands are large. The calculations illustrate the important role of the atomic chemical potentials in determining the relative stability of multiconstituent surface structures.