Nucleation and initial growth in the semimetallic homoepitaxial system of Bi on Bi(111)

Abstract

The nucleation and initial growth of the semimetallic homoepitaxial system of Bi(111) was studied at 130 K by scanning tunneling microscopy. The island density increases with the cubic root of coverage, i.e., ${n}_{x}\ensuremath{\propto}{\ensuremath{\Theta}}^{1/3}$, up to $5.5\ifmmode\times\else\texttimes\fi{}{10}^{11}\text{ }\text{islands}/{\text{cm}}^{2}$ at 0.23 bilayer (BL) coverage. We determined a surface diffusion coefficient of $D=2.6\ifmmode\times\else\texttimes\fi{}{10}^{6}\text{ }{\text{s}}^{\ensuremath{-}1}$. Additionally, a transition of the island shape from compact to quasifractal was observed at about 0.1 BL coverage. The transition island size was estimated to be $70\text{ }{\text{nm}}^{2}$.