Unraveling Intertwined Impacts between Lattice Vacancy and Substrate on Photonic Quasiparticles in Monolayer MoS$_2$

TL;DR

This study disentangles the effects of lattice vacancies and substrate interactions on the photonic quasiparticles in monolayer MoS$_2$, revealing how substrate properties influence defect generation and luminescent behavior.

Contribution

It provides a detailed atomistic analysis of sulfur vacancy impacts on photoluminescence, highlighting substrate-dependent effects in monolayer MoS$_2$.

Findings

Sulfur vacancy generation doubles on hydrophilic substrates.

Substrate hydrophobicity significantly affects sulfur vacancy impact on trionic emission.

Atomistic analysis clarifies extrinsic factors influencing luminescence in 2D semiconductors.

Abstract

Lattice defects and interfacial absorbates represent two extrinsic but ubiquitous factors that exert profound impacts on the luminescent properties of semiconductors. However, their impacts are normally tangled and remain to be separately elucidated. Here, we clarify the individual roles of each factor by tracking the weight evolution of photonic quasiparticles by modulating the densities of sulfur vacancies in monolayer MoS$_2$ via ad hoc defect engineering. In particular, we perform atomistic analyses on the densities of sulfur vacancies by employing atomically resolved scanning transmission electron microscopy to quantitatively characterize the generation rates of sulfur vacancies in MoS$_2$ on two types of substrates with opposite surface hydrophobicity natures. We reveal that the generation rate of sulfur vacancies can even double on the hydrophilic substrates. More importantly, the impact of sulfur vacancies over the weight of trionic emission is closely associated with the substrate hydrophobicity, which is manifested noticeably in the hydrophobic substrates, but insignificant in the hydrophilic ones. The results represent an in-depth understanding on the roles of the extrinsic factors on the luminescent properties in atomically thin semiconductors.