Inter-layer mass transport in a low-coverage, low island-density regime

Abstract

We use Monte Carlo simulations to study inter-layer mass transport during submonolayer epitaxial growth in systems where the ratio of the diffusion coefficient for intra-layer mobility to the deposition flux D F is very high, such that the average diffusion length is comparable to the average terrace length. Under such growth conditions, there exists a low island-density regime where the scaling relation between the island density N and the ratio D F breaks down. We employ realistic terrace boundaries in our simulations (i.e. atom capture at ascending steps and a step edge barrier E s between adjacent substrate terraces at descending steps) to investigate how inter-layer diffusion depends on the D F ratio in this low island-density regime. Information about the magnitude of E s can be extracted by analyzing the distribution of deposited atoms among the three possible capture sites: ascending steps, descending steps and nucleated islands. We apply the results of these simulations to the growth of Ag Ag(111) .