Structural stability and electronic properties of SP3 type silicon nanotubes

TL;DR

This study uses density functional theory to analyze the structural stability and electronic properties of narrow SP3 silicon nanotubes, revealing how growth orientation and chemical composition influence their bandgap and stability.

Contribution

It provides new insights into the stability and electronic tuning of silicon nanotubes through orientation and chemical passivation control.

Findings

Silicon nanotubes are meta-stable with wires being more stable.

Bandgap increases significantly with hydrogen passivation.

Electronic properties can be tailored by controlling growth orientation and composition.

Abstract

A density functional theory study of the structural and electronic properties and relative stability of narrow SP3 silicon nanotubes of different growth orientations is presented. All nanotubes studied and their corresponding wire structures are found to be meta-stable with the wires being more energetically stable. Silicon nanotubes show a dramatic bandgap increase of up to 68% with respect to the corresponding wires. Furthermore, a direct relation between the bandgap of the system and the molar fraction of the passivating hydrogen contents is found. These results suggest that by careful control over their crystallographic growth orientation, dimensions, and chemical composition it should be possible to design and fabricate silicon nanotubes with desired electronic properties.