Measurement of the optical dielectric function of transition metal dichalcogenide monolayers: MoS2, MoSe2, WS2 and WSe2

TL;DR

This study measures the complex dielectric functions of four transition metal dichalcogenide monolayers within 1.5-3 eV, providing insights into their optical properties and comparing them with bulk counterparts.

Contribution

It presents the first detailed dielectric function measurements of MoS2, MoSe2, WS2, and WSe2 monolayers using reflection spectra and Kramers-Kronig analysis.

Findings

Dielectric functions for all four monolayers are characterized.

Absolute absorbance of each monolayer is determined.

Comparison with bulk materials highlights differences in optical properties.

Abstract

We report a determination of the complex in-plane dielectric function of monolayers of four transition metal dichalcogenides: MoS2, MoSe2, WS2 and WSe2, for photon energies from 1.5 - 3 eV. The results were obtained from reflection spectra using a Kramers-Kronig constrained variational analysis. From the dielectric functions, we obtain the absolute absorbance of the monolayers. We also provide a comparison of the dielectric function for the monolayers with the corresponding bulk materials.