Dynamical Monte Carlo simulation of L1₁(CuPt)-type ordering during (001) epitaxial growth of III-V semiconductor alloys

In this study, we have carried out Monte Carlo simulation of L1₁(CuPt)-type ordering in II-V semiconductor alloys of A_0.5B_0.5C during the (001) epitaxial growth, on the basis of an Ising-like model for the layer-by-layer stacking including surface migration of atoms. Fourier power spectra of the atom configurations thus obtained exhibit diffuse streaks running along the growth direction through peaks at 1 2 1 2 1 2 positions indicative of the L1₁-type ordering. An additional tendency for first nearest neighboring atoms toward clustering gives rise to wavy modulation of the streaks such as observed in electron diffraction patterns of epitaxial layers of Ga_0.5In_0.5P or GaAs_0.5Sb_0.5. The result suggests that the epitaxial growth develops L1₁ ordered domains with numerous stacking faults and small like-atom clusters simultaneously within the epilayers.