Quasiparticle band-edge energy and band offsets of monolayer of molybdenum and tungsten chalcogenide

TL;DR

This paper calculates accurate quasiparticle energies and band offsets for monolayer molybdenum and tungsten dichalcogenides, providing essential data for device design and understanding many-electron effects.

Contribution

It presents fully converged quasiparticle energies and band offsets for monolayer MX2, highlighting the importance of many-electron effects and validating the band-gap-center approximation.

Findings

GW calculations show larger bandgaps than previous methods.

Absolute band energies are obtained relative to vacuum level.

Results are crucial for heterojunction and catalytic applications.

Abstract

We report the quasiparticle energy of monolayer of molybdenum and tungsten dichalcogenides, MX2 (M=Mo, W; X=S, Se, Te). Beyond calculating bandgaps, we have achieved converged absolute band energies relative to the vacuum level. Compared with the results from other approaches, the GW calculation reveals substantially larger bandgaps and different absolute band energies because of enhanced many-electron effects. Interestingly, our fully-converged quasiparticle energies ratify the band-gap-center approximation, making it a convenient way to estimate quasiparticle energy. The absolute quasiparticle energies and band offsets obtained in this work are important for designing heterojunction devices and chemical catalysts based on monolayer dichalcogenides.