Manipulation of Exciton Dynamics in Single-Layer WSe2 Using a Toroidal Dielectric Metasurface

TL;DR

This study demonstrates how integrating single-layer WSe2 with toroidal dielectric metasurfaces can significantly enhance and control exciton emission and dynamics, offering new avenues for optoelectronic device development.

Contribution

It introduces a novel approach to manipulate exciton behavior in 2D semiconductors using toroidal resonant metasurfaces, achieving substantial emission enhancement and dynamic control.

Findings

Exciton emission enhanced over tenfold at room and low temperatures.

Temperature tuning controls exciton dynamics and annihilation.

Selective Purcell effect enhancement achieved through spectral overlap.

Abstract

Recent advances in emerging atomically thin transition metal dichalcogenide semiconductors with strong light-matter interactions and tunable optical properties provide novel approaches for realizing new material functionalities. Coupling two-dimensional semiconductors with all-dielectric resonant nanostructures represents an especially attractive opportunity for manipulating optical properties in both the near-field and far-field regimes. Here, by integrating single-layer WSe2 and titanium oxide (TiO2) dielectric metasurfaces with toroidal resonances, we realized robust exciton emission enhancement over one order of magnitude at both room and low temperatures. Furthermore, we could control exciton dynamics and annihilation by using temperature to tailor the spectral overlap of excitonic and toroidal resonances, allowing us to selectively enhance the Purcell effect. Our results provide rich physical insight into the strong light-matter interactions in single-layer TMDs coupled with toroidal dielectric metasurfaces, with important implications for optoelectronics and photonics applications.