Gaas (114) Surface Electronic Structure And Fcc Metal Surface Diffusion Calculation And Theoretical Research

The high-miller surfaces of III-V semiconductors GaAs and diffusion mechanics in the growth of self-diffusion metal surface have received great interests these years. According to recent experiment results, in this paper, we studied the atomic geometry and electronic structure of the GaAs(114) surface and an novel upward-diffusion growth mechanics in FCC metal growth by using the first-principles method and classical molecular dynamics. We get the following conclusion:1. Theoretical study of the GaAs(114) surfaceBased on the density functional theory we carried out our first-principles calculation by using the Vienna ab-initio simulation package (VASP). The results show that after reconstruction there form two As-As dimer and two Ga-Ga rebonded bonds on the surface and the band structure of the surface turn form metal prosperities to semiconductor's. The surface band gap is about 0.8eV. The reasons for the change of band structure and the appeared of band gap are caused by the forming of reconstructed dimer bonds and electronics transfer between the atoms on the surface.2. Simulation an upward-diffusion growth mechanics on the (110) surface of FCC metalsUsing the semi-classical EAM potential and molecular dynamics, we study an novel upward-diffusion growth mechanics in the FCC metal homoepitaxy. By using the molecular dynamics we prove that there can exit an adatom upward-diffusion mechanics through exchange method. We found that an adatom can easily climb up to the top of quantum dot through the exchange diffusion after it diffusion to the edge of step at the mini-(111) and (100) facets but cannot climb down again, which make the quantum dot growth up. This asymmetric upward-diffusion mechanics form a true adatom upward diffusion flow and finally result in the quantum dots formation.