Dark‐Exciton‐Mediated Fano Resonance from a Single Gold Nanostructure on Monolayer WS₂ at Room Temperature

Abstract

carried out to explore Fano resonances that arise from the coupling between surface plasmons (SPs) and excitons in quantum dots (QDs) or dye molecules. [2,[6][7][8][9][10][11] However, the lack of efficient ways to actively tune the excitonic properties of QDs and dye molecules near plasmonic nanostructures makes the development of active devices based on hybrid plasmon-QD/ dye systems challenging. Recently, the interaction between plasmonic nanostructures and emerging 2D semiconductors, including monolayer transition metal dichalcogenides (TMDCs), has attracted the attention of various researchers. [12][13][14] monolayer TMDCs possess high carrier mobility, direct bandgap, and strong excitonic and mechanical properties. Combining these outstanding properties with plasmonic nanostructures, able to confine light at the subwavelength scale and generate energetic hot electrons, holds the promise to enhance the performance of monolayer TMDC-based optoelectronic components and boost the development of miniaturized Strong spatial confinement and highly reduced dielectric screening provide monolayer transition metal dichalcogenides with strong many-body effects, thereby possessing optically forbidden excitonic states (i.e., dark excitons) at room temperature. Herein, the interaction of surface plasmons with dark excitons in hybrid systems consisting of stacked gold nanotriangles and monolayer WS 2 is explored. A narrow Fano resonance is observed when the hybrid system is surrounded by water, and the narrowing of the spectral Fano linewidth is attributed to the plasmon-enhanced decay of dark K-K excitons. These results reveal that dark excitons in monolayer WS 2 can strongly modify Fano resonances in hybrid plasmon-exciton systems and can be harnessed for novel optical sensors and active nanophotonic devices.

Strong Exciton–Plasmon Coupling in a WS2 Monolayer on Au Film Hybrid Structures Mediated by Liquid Ga Nanoparticles

“…Recent studies have successfully demonstrated strong coupling effect at the single nanoparticle level by using semiconducting transition metal dichalcogenide (TMDC) layers, [ 30–35 ] quantum dots (QDs), [ 36 ] molecules, [ 37–41 ] perovskite nanowires, [ 42 ] and TMDC nanodisks. [ 43 ] Due to the lack of efficient ways to control the excitonic orientation of molecules and QDs, the exciton‐plasmon coupling relies on the change of surface plasmon resonance or the polarization of the incident light.…”

High‐Performance Broadband Photodetectors of Heterogeneous 2D Inorganic Molecular Sb2O3/Monolayer MoS2 Crystals Grown via Chemical Vapor Deposition

“…2D materials, such as graphene and transition metal dichalcogenides (TMDCs), have attracted incredible interest because of their extraordinary properties that make them promising candidates for next generation electronic and optoelectronic applications. [ 1–10 ] In contrast to graphene, TMDCs are semiconducting materials with layer‐dependent bandgap in the range of 1−2 eV, [ 11,12 ] exhibiting rich novel fundamental physical properties and promising applications in electronics and optoelectronics. [ 13–16 ] In spite of the attractive photoresponse performances, most of photodetectors based on TMDCs only show photoresponse in visible range, [ 17–19 ] which seriously hinder their real applications.…”

Light‐Controlled Near‐Field Energy Transfer in Plasmonic Metasurface Coupled MoS2Monolayer

“…Resonance. [39] Besides plasmon-2D semiconductors , [27,28] applications in other plasmon-exciton coupling systems, such as plasmon-quantum dots [40,41] and plasmon-dye molecules systems, [42] have also been investigated.…”