| In this thesis, in situ fast-mode scanning tunneling microscopy is used to study the role of domain boundaries in a (p × ✓3)-2Bi adlayer (deposited at under potential conditions) for Bi island nucleation, the anisotropic growth mechanism, the dynamics of Bi growth on Au(111), and the surface morphology of the overpotential deposition (OPD) of Bi on Au(100).;The anisotropic growth of Bi on Au(111) in the overpotential deposition (OPD) region shows a very fast kink dynamic along the [2–10] step direction, i.e. the needle growth direction, but shows a slow lateral growth, which resulted in a slow addition of new kink. Anisotropic growth is favored by the formation of two short bonds between the shifted center atom and its adjacent two corner atoms in the Bi(012) surface unit cell, a rectangular unit cell having four corner atoms and a shifted central atom. The surface lattice along the [2–10] direction resembles a zigzag propagating down that direction. Three types of kink are observed in this step. The energy differences between different types of kink are calculated from Boltzmann distribution and its magnitude is comparable with the coordination energy of each kink type calculated using Bi bond dissociation energy obtained from thermodynamic data.;The surface morphology of Bi growth on Au(100) differs from that observed on Au(1 11). Protruding lines are observed on the surface of Bi deposited at under potential conditions on Au(100) at a potential near the onset of Bi OPD. A further increase of potential toward cathodic values, leads to a two dimensional film growth starting from these narrow lines. The origin of the protrusion is discussed. The morphology of thick Bi deposits is composed of rows, where each row consists of a centered atom surrounded by four corner atoms. An anisotropic growth is found to involve the increase of the length of an individual row. Atomic size needles with only a few atom wide is observed on the surface of Bi overpotentially deposited on Au(100). The atomic size needles can grow in the two directions that are perpendicular to each other. The crystalline structure of Bi deposits on Au(100) is not known. A prediction of the crystalline structure, based on the comparison between our experimental observations and the known bulk Bi crystalline structures, is discussed.;Prior to the OPD of Bi on Au(111), domains are found in the (p × ✓3)-2Bi adlayer deposited at under potential conditions with boundaries between pairs of domains. Domain boundaries have a width of one atom and can attract adatoms and adatom clusters (nuclei). An array of nuclei with its center along a domain boundary are found and its array size fluctuates with respect to time. The phenomenon of nuclei fluctuation in an array is studied. |
