Adatom coalescence and cluster motion on amorphous surfaces via a molecular dynamics computer simulation

Abstract

Abstract A molecular dynamics computer simulation technique of model systems was used to (a) determine the extent of coalescence of a dispersion of adatoms on the amorphous surface as a function of the adatom-substrate interaction energy, and (b) evaluate the effect of the adatom-substrate interaction energy on the mobility of a 10 atom cluster on amorphous and crystalline surfaces. Results show that at low temperatures the diffusion of adatoms on the amorphous surface is limited by the high density of sites from which adatoms require a significant amount of thermal energy in order to escape. At higher temperatures, the amorphous surface can relax and accommodate adatoms and clusters more readily than a low index crystalline surface, again inhibiting diffusion. Such results help explain the experimentally observed high sticking coefficients and higher densities of small clusters experimentally observed in depositions on amorphous surfaces as compared to crystalline surfaces.