Dielectric Property of MoS2 Crystal in Terahertz and Visible Region

TL;DR

This study investigates the dielectric properties of MoS2 crystal across terahertz and visible regions using spectroscopy techniques, revealing models and peaks crucial for optoelectronic applications.

Contribution

It provides detailed dielectric data of MoS2 in THz and visible regions, employing terahertz time-domain spectroscopy and ellipsometry for the first time.

Findings

Dielectric response in THz follows a Drude model due to intrinsic carriers.

In visible region, dielectric behavior fits a Lorentz model with notable peaks at 1.85 and 2.03 eV.

Peaks attributed to interlayer and spin-orbit coupling effects.

Abstract

Two-dimensional materials such as MoS2 have attracted much attention in recent years due to their fascinating optoelectronic properties. Dielectric property of MoS2 is desired for the optoelectronic application. In this paper, terahertz (THz) time-domain spectroscopy and ellipsometry technology are employed to investigate the dielectric response of MoS2 crystal in THz and visible region. The real and imaginary parts of the complex dielectric constant of MoS2 crystal are found to follow a Drude model in THz region, which is due to the intrinsic carrier absorption. In visible region, the general trend of the complex dielectric constant is found to be described with a Lorentz model, while two remarkable peaks are observed at 1.85 and 2.03 eV, which have been attributed to the splitting arising from the combined effect of interlayer coupling and spin-orbit coupling. This work affords the fundamental dielectric data for the future optoelectronic applications with MoS2.