The extreme elastic strain of monolayer transition metal dichalcogenides provides an ideal platform to achieve efficient exciton funneling via local strain modulation; however, studies conducted thus far have focused on the use of substrates with fixed strain profiles. We prepared 1L-WS 2 on a flexible substrate such that the formation of topographic wrinkles could be switched on or off, and the depth or the direction of the wrinkle could be modified by external strain, thereby providing full control of the periodic undulation of the band gap profile of 1L-WS 2 in the range 0−57 meV. Nanoscale photoluminescence (PL) imaging unambiguously evinced that the photoexcited excitons of 1L-WS 2 were accumulated at the top regions of the wrinkles with less band gap than the valley region. Our results of broad tunability of the two-dimensional (2D) exciton funneling suggest a promising route to control exciton drift for enhanced optoelectronic performances and future 2D exciton devices.

While a hexagonal WS2 monolayer, grown by chemical vapor deposition, exhibits distinctive patterns in photoluminescence mapping, segmented with alternating S‐vacancy (SV) and W‐vacancy (WV) domains in a single crystal, the formation mechanism for native alternating defect domains remains unresolved to date. Here, the formation mechanism of alternating defect domains in hexagonal WS2 via the precursor accumulation model is experimentally elucidated. A triangular WS2 seed is initially formed, followed by a hexagonal flake. Alternating W‐rich (SV) and W‐deficient (WV) domains are constructed in hexagonal WS2 flake, which is confirmed by confocal photoluminescence mapping and secondary ion mass spectroscopy. This is explained by the accumulation or scarcity of W‐precursors at the edge of the WS2 flake. The W‐precursors accumulate near the edges of the initial triangular WS2 seed over time, while they are deficient near the corners of the triangular WS2, eventually forming WV domains in the truncated hexagonal domains. The heterogeneous accumulation becomes more prominent in the presence of H2 gas through desorption of the W‐precursors.

Monolayer transition metal dichalcogenides (TMDs) with a direct band gap are suitable for various optoelectronic applications such as ultrathin light emitters and absorbers. However, their weak light absorption caused by the atomically thin layer hinders more versatile applications for high optical gains. Although plasmonic hybridization with metal nanostructures significantly enhances light−matter interactions, the corrosion, instability of the metal nanostructures, and the undesired effects of direct metal−semiconductor contact act as obstacles to its practical application. Herein, we propose a dielectric nanostructure for plasmon-enhanced light−matter interaction of TMDs. TiO 2 nanowires (NWs), as an example, are hybridized with a MoS 2 monolayer on various substrates. The structure is implemented by placing a monolayer MoS 2 between a TiO 2 NW for a photonic scattering effect and metallic substrates with a spacer for the plasmonic Purcell effect. Here, the thin dielectric spacer is aimed at minimizing emission quenching from direct metal contact, while maximizing optical field localization in ultrathin MoS 2 near the TiO 2 NW. An effective emission enhancement factor of ∼22 is attained for MoS 2 near the NW of the hybrid structure compared to the one without NWs. Our work is expected to facilitate a hybridized platform based on 2D semiconductors for high-performance and robust optoelectronics via engineering dielectric nanostructures with plasmonic materials.

Two‐dimensional (2D) transition‐metal dichalcogenide (TMD) monolayers of versatile material library are spotlighted for numerous unexplored research fields. While monolayer TMDs exhibit an efficient excitonic emission, the weak light absorption arising from their low dimensionality limits potential applications. To enhance the light–matter interactions of TMDs, while various plasmonic hybridization methods have been intensively studied, controlling plasmonic nanostructures via self‐assembly processes remains challenging. Herein, strong light–matter interactions are reported in plasmonic Ag nanoparticles (NPs) hybridized on TMDs via an aging‐based self‐assembly process at room temperature. This hybridization is implemented by transferring MoS2 monolayers grown via chemical vapor deposition onto thin‐spacer–covered Ag films. After a few weeks of aging in a vacuum desiccator, the Ag atoms in the heterolayered film diffuse to the MoS2 layers through a SiO2 spacer and self‐cluster onto MoS2 point defects, resulting in the formation of Ag‐NPs with an estimated diameter of ≈50 nm. The photoluminescence intensities for the Ag‐NP/MoS2 hybrids are enhanced up to 35‐fold compared with bare MoS2 owing to the local field enhancement near the plasmonic Ag‐NPs. The localized surface plasmon resonances modes of this hybrid are systematically investigated via numerical simulations and dark‐field scattering microscopy.

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