Interlayer and intralayer excitons in AlN/WS$_2$ heterostructure

TL;DR

This paper investigates the electronic and optical properties of an AlN/WS₂ heterostructure using first principles calculations, highlighting the importance of many-body effects in accurately predicting band alignment for optoelectronic applications.

Contribution

It demonstrates how many-body effects alter the band alignment in AlN/WS₂ heterostructures, emphasizing their necessity for correct property predictions.

Findings

Many-body effects change the heterostructure band alignment from type II to I.

Inclusion of many-body effects is essential for accurate electronic and optical property prediction.

The heterostructure shows potential for optoelectronic and photocatalytic applications.

Abstract

Transition metal dichalcogenides (TMD) monolayers, holding potential as good sunlight absorbers, are promising materials for next-generation optoelectronic devices. They may enable ultrathin photovoltaic(PV) devices thanks to their semiconducting character. In addition, heterocombinations of AlN and GaN sheets with MoS$_2$ monolayers have been suggested to be efficient water-splitting devices. Following these promising findings and motivated by the small lattice mismatch, we take up the idea of coupling a semiconducting WS$_2$ TMD monolayer with a AlN monolayer in a vdW heterostructure which is, as well, promising for photo-catalysis or photo-voltaic devices. We study this heterostructure by means of first principles calculations, and we show that many-body effects change the heterostructure band alignment from type II to I, demonstrating how their inclusion is compulsory for a correct prediction of the electronic and optical properties of 2D materials.