The difference between Si and Ge(001) surfaces in the initial stages of growth

TL;DR

This study compares the initial epitaxial growth stages of Ge and Si on their respective (001) surfaces, revealing directional differences in metastable ad-dimer rows that influence growth behavior due to chemical differences.

Contribution

It uncovers the directional preferences of metastable ad-dimer rows on Ge(001) versus Si(001), highlighting the impact of elemental chemistry on epitaxial growth.

Findings

Ge(001) rows are exclusively in <310> directions

Si(001) rows prefer <110> directions

Differences are due to chemical properties of Ge and Si

Abstract

The initial stages of growth of Ge and Si on the Ge(001) surface are studied and compared to growth on the Si(001) surface. Metastable rows of diluted ad-dimers exist on both surfaces as intermediate stages of epitaxial growth. Unexpectedly, for Ge(001) these rows are found exclusively in the <310> directions, whereas on Si(001) the preferred direction is <110>. This qualitative difference between Si and Ge surfaces reflects the subtle difference in the chemistry of these two elements, which has direct consequences for epitaxial growth on these surfaces.