Effects of mobile and immobile impurities on two-dimensional nucleation

The effect of impurities on epitaxial growth in the submonolayer regime is studied using kinetic Monte Carlo simulations of a two-species solid-on-solid growth model. The dependence of the island density on flux and concentration of impurities is studied in detail. Significantly different behavior is observed for mobile and immobile impurities. For the case of immobile impurities simple scaling arguments explain the main features of the data.