Absorbance Enhancement of Monolayer MoS$_2$ in a Perfect Absorbing System

TL;DR

This study demonstrates that dielectric resonances can significantly enhance the absorbance and emission of monolayer MoS$_2$, and proposes a perfect absorbing structure with a gold mirror to maximize absorption.

Contribution

The paper introduces a hybrid MoS$_2$-disk system with a gold mirror that achieves near-complete absorption of incident light, surpassing previous limitations.

Findings

Dielectric resonance enhances MoS$_2$ absorbance and emission.

A model explains emission enhancement via absorbance and quantum efficiency.

A perfect absorber with a gold mirror absorbs 53% of incident power.

Abstract

We reveal numerically and experimentally that dielectric resonance can enhance the absorbance and emission of monolayer MoS$_2$. By quantifying the absorbance of the Si disk resonators and the monolayer MoS$_2$ separately, a model taking into account of absorbance as well as quantum efficiency modifications by the dielectric disk resonators successfully explains the observed emission enhancement under the normal light incidence. It is demonstrated that the experimentally observed emission enhancement at different pump wavelength results from the absorbance enhancement, which compensates the emission quenching by the disk resonators. In order to further maximize the absorbance value of monolayer MoS$_2$, a perfect absorbing structure is proposed. By placing a Au mirror beneath the Si nanodisks, the incident electromagnetic power is fully absorbed by the hybrid monolayer MoS$_2$-disk system. It is demonstrated that the electromagnetic power is re-distributed within the hybrid structure and 53\% of the total power is absorbed by the monolayer MoS$_2$ at the perfect absorbing wavelength.