Fast coarsening in unstable epitaxy with desorption

TL;DR

This paper demonstrates that even a small amount of desorption significantly accelerates mound coarsening during unstable epitaxial growth, with coarsening exponents reaching up to 1/2, through simulations of lattice and continuum models.

Contribution

It reveals how desorption influences coarsening dynamics in unstable epitaxy, providing new insights into the growth process mechanisms.

Findings

Desorption speeds up mound coarsening.

Coarsening exponents range from 1/3 to 1/2.

Larger mounds grow faster due to lower evaporation rates.

Abstract

Homoepitaxial growth is unstable towards the formation of pyramidal mounds when interlayer transport is reduced due to activation barriers to hopping at step edges. Simulations of a lattice model and a continuum equation show that a small amount of desorption dramatically speeds up the coarsening of the mound array, leading to coarsening exponents between 1/3 and 1/2. The underlying mechanism is the faster growth of larger mounds due to their lower evaporation rate.