Chemical Tuning on Resonance Coupling in Gold Nanorod−Monolayer WS2 Heterostructures

S.p Wen ,Huanjun Chen,Shiyu Deng,Kun Chen,Shaozhi Deng

doi:10.3389/fmats.2021.744275

Abstract

Resonance coupling between plasmonic resonances in metallic nanostructures and excitons in two-dimensional (2D) semiconductors has attracted much recent attention. The 2D semiconductor excitons are sensitive to external stimulus, enabling active tuning on the resonance couplings by physical, such as applying electrostatic gating, thermal scanning, etc., or chemical approaches. Among the others, chemical tuning approach has the advantage of facile implementation, high efficiency, and being capable of large-area tuning. Here, we report on chemical tuning of resonance coupling in heterostructures consisted of individual gold nanorods integrated with monolayer WS2. We showed that by incubating the heterostructures into a bis (trifluoro-methane) sulfonimide (TFSI) solution, the exciton transition strength of the WS2 will be enhanced significantly. As a result, the resonance coupling in the heterostructures evolved from a weak coupling regime to a strong coupling one, with the mode splitting energy increases from 94.96 to 105.32 meV. These findings highlight the potential of chemical treatment as an efficient technique for tailoring the interactions between plasmonic nanostructures and 2D semiconductors.

Highlights

Resonance coupling refers to interactions between quantum emitters and optical cavity with spectrally overlapped resonances, which has great potentials in a variety of applications such as low-threshold lasers, ultrafast optical switches, as well as quantum information processings (Chen et al, 2013; Sanvitto and Kéna-Cohen, 2016; Baranov et al, 2018; Zheng et al, 2020; Huang et al., 2021)
The as-prepared gold nanorods have uniform size and shape distributions (Figure 1A; Supplementary Figure S1), where two types of localized surface plasmon resonances (LSPRs) modes can be observed from their extinction spectra (Figure 1B; Supplementary Figure S1M)
The LPM is considered because its resonance wavelengths can be synthetically tuned by tailoring the aspect ratio of the gold nanorods (Figure 1B; Supplementary Figure S1M), which is defined as the nanorod length divided by the diameter (Chen et al, 2013)

Summary

Introduction

Resonance coupling refers to interactions between quantum emitters and optical cavity with spectrally overlapped resonances, which has great potentials in a variety of applications such as low-threshold lasers, ultrafast optical switches, as well as quantum information processings (Chen et al, 2013; Sanvitto and Kéna-Cohen, 2016; Baranov et al, 2018; Zheng et al, 2020; Huang et al., 2021). We report the chemical tuning of resonance coupling in heterostructures composed of individual gold nanorods integrated with monolayer WS2.

Results

Conclusion