Carrier Dynamics in High-density Photo-doped MoS$_2$: Monolayer vs Multilayer

TL;DR

This study compares the ultrafast carrier dynamics of monolayer and multilayer MoS$_2$ at high photo-doping densities, revealing significant differences influenced by the full band structure, which impacts optoelectronic applications.

Contribution

It provides a detailed analysis of carrier processes in monolayer versus multilayer MoS$_2$ at high excitation densities, highlighting the role of band structure effects.

Findings

Distinct carrier relaxation behaviors in monolayer and multilayer MoS$_2$

Band structure influences ultrafast dynamics despite similar near-K-point features

Insights into exciton dissociation and bandgap renormalization effects

Abstract

Monolayer and multilayer MoS$_2$ are extremely fascinating materials for the use in lasers, compact optical parametric amplifiers, and high-power detectors which demands high excitation light-matter interaction. Consequently, it is essential to understand the carrier dynamics in both the cases at such high excitation densities. In this work, we investigate the carrier dynamics of monolayer and multilayer MoS$_2$ at photo-doping densities around Mott Density. It is observed that, despite the similarity in band structure near K-point and formation of A-exciton, a substantial difference in the carrier dynamics is observed reflecting the influence of the entire band structure. The exciton dissociation, bandgap renormalization, and intervalley relaxation play a consequential role in dictating the ultrafast transient properties of these samples. The study in this paper provide a substantial understanding of fundamental optoelectronic properties of the two-dimensional MoS$_2$, paving a way for its potential applications in various photonic and optoelectronic domain.