Kinetic Monte Carlo study of fractal growth with edge diffusion and reversible aggregation on a bcc(1 1 0) surface

Abstract

The low-coverage growth of Cu islands deposited on W(110) is studied by kinetic Monte Carlo simulation. The model includes deposition, diffusion of monomers, diffusion along island edges and reversible aggregation on centered rectangular lattice with anisotropy of diffusion barriers. The simulations are performed at temperatures from 150 to 280K with fluxes changing from 10−7 to 10−3 Ml/s. Island morphology ranges from ramified structures (fractals) at low temperatures to compact shapes at higher temperatures. The low temperature growth regime consists of standard diffusion limited aggregation regime and extended fractal regime. The existence of EF regime at bcc(110) surface results from the inhibition of island equilibration by two neighboring bonds of edge adatom to an island in a centered rectangular lattice. The fractals obtained in EF regime have arms that widen with increasing temperature as it is observed in experiments for other systems. The submonolayer morphology diagram in the (flux, temperature) plane is presented and the region of possible fractal observation is indicated.