Competing roughening mechanisms in strained heteroepitaxy: a fast kinetic Monte Carlo study

TL;DR

This paper uses advanced kinetic Monte Carlo simulations with a novel Green's function approach to study how strained heteroepitaxial films evolve morphologically, revealing different island formation mechanisms depending on temperature and lattice misfit.

Contribution

It introduces a new Green's function method for efficient elastic energy calculation in kinetic Monte Carlo simulations of heteroepitaxial films.

Findings

Island formation at low misfit and high temperature aligns with the Asaro-Tiller-Grinfeld instability.

At high misfit and low temperature, islands or pits form via nucleation.

The study distinguishes between different morphological evolution mechanisms based on conditions.

Abstract

We study the morphological evolution of strained heteroepitaxial films using kinetic Monte Carlo simulations in two dimensions. A novel Green's function approach, analogous to boundary integral methods, is used to calculate elastic energies efficiently. We observe island formation at low lattice misfit and high temperature that is consistent with the Asaro-Tiller-Grinfeld instability theory. At high misfit and low temperature, islands or pits form according to the nucleation theory of Tersoff and LeGoues.