From Layers to Nanotubes: Transition Metal Disulfides TMS2

TL;DR

This study compares the electronic structures of bulk, monolayer, and nanotube forms of transition metal disulfides, revealing how nanotube chirality influences their semiconductor properties and potential optoelectronic applications.

Contribution

It provides a first-principles analysis of how nanotube structure affects the electronic properties of transition metal disulfides.

Findings

Armchair nanotubes remain indirect gap semiconductors.

Zigzag nanotubes are direct gap materials, like monolayers.

Potential for optoelectronic applications based on nanotube chirality.

Abstract

MoS2 and WS2 layered transition-metal dichalcogenides are indirect band gap semiconductors in their bulk forms. Thinned to a monolayer, they undergo a transition and become direct band gap materials. Layered structures of that kind can be folded to form nanotubes. We present here the electronic structure comparison between bulk, monolayered and tubular forms of transition metal disulfides using first-principle calculations. Our results show that armchair nanotubes remain indirect gap semiconductors, similar to the bulk system, while the zigzag nanotubes, like a monolayer, are direct gap materials, what suggests interesting potential applications in optoelectronics.