Simulation Studies On The Film Nucleation And Growth Kinetics In The Submonolayer Regime

Studies of the morphological evolution process of two-dimensional islands in submono-layer epitaxial growth have been active in the area of surface science. This is because, the shape and the spatial size distribution of such two-dimensional islands in submonolayer epitaxial growth closely relates to the overall quality of multilayer films. In this thesis, based on the recent experimental observations by STM, the nucleation and growth behavior of two-dimensional islands in the initial stage of film epitaxial growth were investigated by using kinetic Monte Carlo simulation and rate equation analysis; the relevant surface pattern formation and morphological evolution were studied by cellular automaton simulation. The thesis consists of following six chapters.Chapter One presents a brief introduction to the film growth modes and the basic atomistic processes in the initial stage of film growth, and a review of research progress on the theories and computer simulation about film growth.Chapter Two devotes to study the epitaxial growth of ultra-thin metal films. The dependence of island shape and density on the growth parameters, such as temperature, flux, and coverage, is investigated; the influence of substrate symmetry on the cluster formation is discussed With a multifractal theory the nonuniform distribution of the multiple cluster formation is then characterized quantitatively.Chapter Three studies the two-dimensional pattern formation in surfactant-mediated epitaxy by a kinetic Monte Carlo simulation. By introducing a configuration-dependent exchange barrier and considering the exchange asymmetry at the island edge, the anisotropic dendritic and regular compact islands are obtained. Furthermore, based on the first principle calculation results, a diffusion-exchange-reexchange model for surfactant-mediated epitaxy growth is constructed. A rate equation analysis of the model shows that, nucleus density governed by...