Damping of Oscillations in Layer-by-Layer Growth

TL;DR

This paper develops a theoretical model for the damping of oscillations during layer-by-layer growth in molecular beam epitaxy, linking surface roughness evolution to growth conditions and confirming results with simulations.

Contribution

It introduces a new theory that quantitatively describes the damping of growth oscillations and predicts their dependence on temperature and deposition rate.

Findings

Damping time depends on roughening and smoothening mechanisms.

Surface roughness becomes significant beyond a certain coherence length.

Theoretical predictions are validated by computer simulations.

Abstract

We present a theory for the damping of layer-by-layer growth oscillations in molecular beam epitaxy. The surface becomes rough on distances larger than a layer coherence length which is substantially larger than the diffusion length. The damping time can be calculated by a comparison of the competing roughening and smoothening mechanisms. The dependence on the growth conditions, temperature and deposition rate, is characterized by a power law. The theoretical results are confirmed by computer simulations.