Metallic and semi-metallic <100> silicon nanowires

TL;DR

This study uses density functional calculations to analyze <100> silicon nanowires, revealing two surface reconstructions with distinct electronic properties, one metallic and one semi-metallic, influencing their conductivity without doping.

Contribution

It identifies two dominant surface reconstructions in silicon nanowires and links their electronic properties to surface states, showing potential for doping-free conductive nanowires.

Findings

One reconstruction is strongly metallic.

The other is semi-metallic.

Doping may not be necessary for conductivity.

Abstract

Silicon nanowires grown along the <100>-direction with a bulk Si core are studied with density functional calculations. Two surface reconstructions prevail after exploration of a large fraction of the phase space of nanowire reconstructions. Despite their energetical equivalence, one of the reconstructions is found to be strongly metallic while the other one is semi-metallic. This electronic-structure behavior is dictated by the particular surface states of each reconstruction. These results imply that doping is not required in order to obtain good conducting Si nanowires.