Probing Nanoscale Exciton Funneling at Wrinkles of Twisted Bilayer MoS₂ Using Tip-Enhanced Photoluminescence Microscopy

Recent Strategies for the Synthesis of Phase-Pure Ultrathin 1T/1T′ Transition Metal Dichalcogenide Nanosheets

“…189 Although the surface of the MoS 2 twisted bilayer appears very uniform under far-field PL imaging, nanoscale wrinkles are detected using TEPL owing to the exciton funneling in the high-strain area, as shown in Figure 10 (e). 76 Owing to the enhanced resolution of TEPL, the interaction between excitons and plasmons has also been used to intensify the PL emission at room temperature. Li et al demonstrated that the trion emission was substantially suppressed, the strainlocalized excitons were red-shifted by 200 meV when the WS 2 monolayer was deposited on plasmonic gold nanoparticles, and the emission was coincidentally polarized with that of the gold nanorods.…”

Probing the Role of Environmental and Sample Characteristics in Gap Mode Tip-Enhanced Raman Spectroscopy

“…This sets it apart from super-resolution fluorescence microscopy, which typically requires labeling, and electron microscopy, which necessitates a vacuum environment. For example, ambient scanning tunneling microscopy (STM)- and atomic force microscopy (AFM)-based TERS has been successfully utilized for nanoscale probing of supported lipid monolayers, heterogenous catalysts, on-surface degradation chemistry, polymeric materials, biological cells, , organic photovoltaic devices, monolayer graphene, monolayer transition-metal dichalcogenides, , coordination complexes, self-assembled monolayers, electrochemical transformations, − etc. However, a persistent problem in ambient TERS measurements is the frequent occurrence of intense and short-lived spurious signals, which complicates the analysis and interpretation of experimental data. , Although such spurious signals are often attributed to atmospheric carbon contaminants (ACCs) or carbonaceous decomposition products, − their precise origin is still unclear.…”

Tip-enhanced nanoscopy of two-dimensional transition metal dichalcogenides: progress and perspectives

“…In recent years, TMDs composed of periodic layers of transition metals and chalcogenide elements have emerged as a new class of optoelectronic materials owing to their unique physical properties such as high electron mobility, 1 large exciton binding energy, 2 large spin–orbit splitting energy, 3 etc . Defects, such as vacancies, 4 grain boundaries, 5 dislocations, 6,7 nonstoichiometric fluctuations, 8 wrinkles, 9 organic residues, 10 etc ., are crucial factors affecting the electronic and optical properties of monolayer (1L) TMDs and their HJs and twisted thick layers. For TMD HJs, interlayer diffusion and the resulting interfacial alloying effect can also be classified as a general defect.…”