Band structure of hydrogenated Si nanosheets and nanotubes

TL;DR

This paper investigates the electronic band structure of hydrogenated silicon nanosheets and nanotubes, revealing their semiconducting properties and unique gap behaviors, with implications for novel semiconductor applications.

Contribution

It introduces a detailed analysis of hydrogenated Si nanostructures' band structures using an empirical tight-binding model, highlighting new gap phenomena.

Findings

Hydrogenated Si nanosheets are semiconductors with ~2.2 eV indirect band gap.

Certain chiralities of hydrogenated Si nanotubes exhibit co-existing direct and indirect gaps.

Comparison with ab initio calculations supports the tight-binding results.

Abstract

The band structure of fully hydrogenated Si nanosheets and nanotubes are elucidated by the use of an empirical tight-binding model. The hydrogenated Si sheet is a semiconductor with indirect band gap of about 2.2 eV. The symmetries of the wave functions allow us to explain the origin of the gap. We predict that, for certain chiralities, hydrogenated Si nanotubes represent a new type of semiconductor, one with co-existing direct and indirect gaps of exactly the same magnitude. This behavior is different from the Hamada rule established for non-hydrogenated carbon and silicon nanotubes. Comparison to an ab initio calculation is made.