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

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)proportional to Theta(1/3), up to 5.5x10(11) islands/cm(2) at 0.23 bilayer (BL) coverage. We determined a surface diffusion coefficient of D=2.6x10(6) s(-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 nm(2).