Island formation and the heterogeneous nucleation of aluminum

MR O'Masta and EC Clough and JH Martin, COMPUTATIONAL MATERIALS SCIENCE, 192, 110317 (2021).

DOI: 10.1016/j.commatsci.2021.110317

Liquid phase epitaxy of aluminum on substrates of varying lattice spacing is investigated. Molecular dynamic simulations show the formation and growth of small (nm to ?m) islands following a Stranski- Krastanov mode, where a few unit cell thick, solid layer first templates to the substrate. Subsequent island formation reduces the strain energy within the nucleating solid. Growing islands coalesce upon impinging, while misfit dislocations form during growth and remain at the substrate interface. A thermodynamic analysis reveals island creation is a stochastic process, requiring thermal energy to overcome an activation barrier. Relative to a planar growth criterion, island growth becomes the prominent mechanism at moderate lattice mismatch between the solid and substrate. The difference in activation undercooling between the two growth mechanisms increases with mismatch magnitude. The presented model is used to evaluate island growth for other metals, and can be used as a criterion for activation of a catalyzing surface.

Return to Publications page