Size effects in surface reconstructed $<100>$ and $< 110>$ silicon nanowires

TL;DR

This study uses density-functional calculations to explore how surface reconstruction affects the geometric and electronic properties of silicon nanowires in different orientations and sizes, revealing surface metallic states.

Contribution

It provides a detailed analysis of size and orientation effects on surface reconstruction and electronic states in silicon nanowires without passivation.

Findings

Surface reconstruction can induce metallic states.

Electronic properties depend on wire size and growth direction.

Reconstruction effects vary with nanowire orientation.

Abstract

The geometrical and electronic structure properties of $<100>$ and $<110>$ silicon nanowires in the absence of surface passivation are studied by means of density-functional calculations. As we have shown in a recent publication [R. Rurali and N. Lorente, Phys. Rev. Lett. {\bf 94}, 026805 (2005)] the reconstruction of facets can give rise to surface metallic states. In this work, we analyze the dependence of geometric and electronic structure features on the size of the wire and on the growth direction.