Effects of substrate anisotropy and edge diffusion on submonolayer growth during molecular beam epitaxy: A Kinetic Monte Carlo study

TL;DR

This study uses Kinetic Monte Carlo simulations to analyze how substrate anisotropy and edge diffusion affect island formation and morphology during submonolayer growth in molecular beam epitaxy, revealing their distinct roles.

Contribution

It provides new insights into the effects of substrate anisotropy and edge diffusion on island morphology and growth dynamics in MBE, using a simple cubic solid-on-solid model.

Findings

Substrate anisotropy influences island morphology and growth exponent.

Edge diffusion affects island compactness but not elongation.

Fractal islands form without edge diffusion, compact islands with edge diffusion.

Abstract

We have performed Kinetic Monte Carlo simulation work to study the effect of diffusion anisotropy, bonding anisotropy and edge diffusion on island formation at different temperatures during the sub-monolayer film growth in Molecular Beam Epitaxy. We use simple cubic solid on solid model and event based Bortz, Kalos and Labowitch (BKL) algorithm on the Kinetic Monte Carlo method to simulate the physical phenomena. We have found that the island morphology and growth exponent are found to be influenced by substrate anisotropy as well as edge diffusion, however they do not play a significant role in island elongation. The growth exponent and island size distribution are observed to be influenced by substrate anisotropy but are negligibly influenced by edge diffusion. We have found fractal islands when edge diffusion is excluded and compact islands when edge diffusion is included.