Comparative Monte Carlo Study of Monolayer Growth in a Heteroepitaxial System in the Presence of Surface Defects

Abstract

The adsorption of a metal monolayer or submonolayer for the systems Ag/Au(100), Au/Ag(100), Ag/Pt(100), Pt/Ag(100), Au/Pt(100), Pt/Au(100), Au/Pd(100), and Pd/Au(100) was studied by means of lattice Monte Carlo simulations. It was found that, taking into account some general trends, such systems can be classified into two big groups. The first one comprises Ag/Au(100), Ag/Pt(100), Au/Pt(100), and Au/Pd(100), which have favorable binding energies as compared with the homoepitaxial growth of adsorbate-type atoms. When the simulations are performed in the presence of substrate-type islands in order to emulate surface defects, the islands remain almost unchanged, and the adsorbate atoms successively occupy kink sites, step sites, and the complete monolayer. The second group is composed of Au/Ag(100), Pt/Ag(100), Pt/Au(100), and Pd/Au(100), for which monolayer adsorption is more favorable on substrates of the same nature than on the considered substrates. When simulations are carried out in the presence of islands of substrate-type atoms, these tend to disintegrate in order to form 2D alloys with adsorbate atoms.