Dynamical Monte Carlo studies of molecular beam epitaxial growth models: interfacial scaling and morphology

Abstract

We have modeled molecular beam epitaxial growth by d = 2 + 1 solid-on-solid models using dynamical Monte Carlo simulations. The chosen parameters are representative values of those derived from experimental molecular beam epitaxial growth of GaAs(100), and simulations were carried out over the experimentally relevant range of independent variables. We discuss the effects of growth temperature, transient mobility of incoming particles and Schwoebel barriers on the evolution of surface morphology and interfacial roughness. The interfacial properties are measured by the interfacial width, kink density, and reflection high-energy electron diffraction intensity at the out-of-phase condition. The temporal effective growth exponent, β eff, calculated as a function of temperature, shows a crossover from growth by random deposition at low temperature ( β eff = 0.5) to Edwards-Wilkinson growth at high temperature ( β eff = 0). A small plateau is observed at intermediate temperatures, at which β eff ≈ 0.22. Increasing the transient mobility of a precursor state (“hot” precursor) at low temperature also leads to a crossover from growth by random deposition to Edwards-Wilkinson growth, and β eff as a function of transient migration probability may show a plateau around β eff ≈ 0.25. However, increasing the Schwoebel barrier leads to a crossover from layer-by-layer growth to three-dimensional growth with β eff = 0.5 at high surface temperature. We also discuss these results qualitatively within the context of a coarse-grained description.