Published online by Cambridge University Press: 25 February 2011
Whenever an atom of As is substitutionally replaced by a P-atom in a compound such as GaAs, due to the difference in ionicity, local puckering is effected by charge transfer. This paper deals with a calculation of the total energy stored, Eex = E(strain) + E(interface) = Es + Eint. For thick epilayers of GaP on GaAs, Eex is dominated by Es. However, for severalatomic layers of GaP on GaAs, the dominant stored energy is actually represented by the electrical dipole-dipole energy at the interface. The creation of dislocations may release the strain energy, it cannot affect the interface dipoleterm. Only inter-diffusion can lower the interface energy.