Electronic Properties of TiO$_2$ Nanotubes

TL;DR

This study models TiO2 nanotubes' electronic properties, revealing their semiconducting nature, how band gaps vary with diameter, and identifying the strongest bonds within the structures.

Contribution

It provides the first detailed modeling of TiO2 nanotubes' electronic properties using tight-binding theory, highlighting their semiconducting behavior and bond strength characteristics.

Findings

All nanotubes are semiconducting with band gaps decreasing as diameter shrinks.

Larger diameter nanotubes tend to form zigzag configurations.

Ti-O bonds are the strongest interactions in TiO2 nanotubes.

Abstract

quasi-one-dimensional (1D) titania nanostructures - single-walled nanotubes formed by rolling [101] planes of TiO$_2$ (anatase phase) are modeled and their electronic properties and bond orders indices are studied using the tight-binding band theory. We show that all zigzag (n,0)- and armchair (n,n)-like nanotubes are uniformly semiconducting, and the band gap trends to vanish as the tube diameters decrease. It was established that the zigzag (n,0) nanotubes configurations are more likely to form when the diameters are larger 1 nm. The Ti-O covalent bonds were found to be the strongest interactions in TiO$_2$ tubes, whereas Ti-Ti bonds proved to be much weaker.