Many classes of two-dimensional (2D) materials have emerged as potential platforms for novel electronic and optical devices. However, their physical properties are strongly influenced by nanoscale heterogeneities in the form edges, twin boundaries, nucleation sites. Using combined tip-enhanced Raman scattering photoluminescence (PL) nanospectroscopy nanoimaging, we study associated effects on excitonic monolayer WSe2 grown vapor deposition. With ∼15 nm spatial resolution, resolve...

Optical cavities can enhance and control light-matter interactions. This level of has recently been extended to the nanoscale with single emitter strong coupling even at room temperature using plasmonic nanostructures. However, emitters in static geometries, limit ability tune strength or couple different same cavity. Here, we present tip-enhanced (TESC) a nanocavity formed between scanning antenna tip substrate. By reversibly dynamically addressing quantum dots, observe mode splitting up...

Abstract The tunability of the bandgap, absorption and emission energies, photoluminescence (PL) quantum yield, exciton transport, energy transfer in transition metal dichalcogenide (TMD) monolayers provides a new class functions for wide range ultrathin photonic devices. Recent strain‐engineering approaches have enabled to tune some these properties, yet dynamic control at nanoscale with real‐time ‐space characterizations remains challenge. Here, nano‐mechanical naturally‐formed wrinkles...

Understanding and controlling the nanoscale transport of excitonic quasiparticles in atomically thin two-dimensional (2D) semiconductors are crucial to produce highly efficient nano-excitonic devices. Here, we present a nanogap device selectively confine excitons or trions 2D transition metal dichalcogenides at nanoscale, facilitated by drift-dominant exciton funneling into strain-induced local spot. We investigate spatiospectral characteristics funneled WSe2 monolayer (ML) converted MoS2 ML...

Abstract Emerging photo-induced excitonic processes in transition metal dichalcogenide (TMD) heterobilayers, e.g., interplay of intra- and inter-layer excitons conversion to trions, allow new opportunities for ultrathin hybrid photonic devices. However, with the associated large degree spatial heterogeneity, understanding controlling their complex competing interactions TMD heterobilayers at nanoscale remains a challenge. Here, we present an all-round dynamic control interlayer-excitons...

Structure, dynamics, and coupling involving single-molecules determine function in catalytic, electronic or biological systems. While vibrational spectroscopy provides insight into molecular structure, rapid fluctuations blur the trajectory even single-molecule spectroscopy, analogous to spatial averaging measuring large ensembles. To gain intramolecular coupling, substrate dynamic processes, we use tip-enhanced Raman (TERS) at variable cryogenic temperatures, slow control motion of a single...

Abstract Photoluminescence (PL), a photo-excited spontaneous emission process, provides wealth of optical and electronic properties materials, which enable microscopic spectroscopic imaging, biomedical sensing diagnosis, range photonic device applications. However, conventional far-field PL measurements have limitations in sensitivity spatial resolution, especially to investigate single nano-materials or nano-scale dimension them. In contrast, tip-enhanced photoluminescence (TEPL)...

The generation of high-purity localized trions, dynamic exciton-trion interconversion, and their spatial modulation in two-dimensional (2D) semiconductors are building blocks for the realization trion-based optoelectronic devices. Here, we present a method all-optical control exciton-to-trion conversion process its distributions MoS2 monolayer. We induce nanoscale strain gradient 2D crystal transferred on lateral metal-insulator-metal (MIM) waveguide exploit propagating surface plasmon...

Controlling the propagation and polarization vectors in linear nonlinear optical spectroscopy enables us to probe anisotropy of responses providing structural symmetry selective contrast imaging. Here, we present a novel tilted antenna-tip approach control vector-field by breaking axial nanoprobe tip-enhanced near-field microscopy. This gives rise localized plasmonic antenna effect with significantly enhanced field both in-plane out-of-plane components. We use resulting specificity response...

Imaging biological systems with simultaneous intrinsic chemical specificity and nanometer spatial resolution in their typical native liquid environment has remained a long-standing challenge. Here, we demonstrate general approach of nanoimaging based on infrared scattering scanning near-field optical microscopy (IR s-SNOM). It is enabled by combining AFM operation fluid cell evanescent IR illumination via total internal reflection, which provides spatially confined excitation for minimized...

Abstract In atomically thin semiconductors, localized exciton (X L ) coupled to light provides a new class of optical sources for potential applications in quantum communication. However, most studies, X photoluminescence (PL) from crystal defects has mainly been observed cryogenic conditions because their sub‐wavelength emission region and low yield at room temperature. Hybrid‐modality cavity‐spectroscopy induce probe the emissions nanoscale semiconductors is presented. By placing WSe 2...

The bilayer grain boundaries (GBs) in chemical-vapor-deposition-grown large-area graphene are identified using multispectral tip-enhanced Raman imaging with 18 nm spatial resolution. misorientation angle of the GBs is determined from a quantitative analysis phonon-scattering properties associated modified electronic structure.

We used low-temperature reactions to synthesize different-sized CdSe quantum dots (QDs) capped with fatty-acid and phosphine ligands. From the correlation of high-resolution transmission electron microscopy X-ray diffraction (XRD) analyses synthesized QDs, we observed size-dependent shape anisotropy. In addition, recorded XRD patterns revealed mixed crystal facets zinc blende wurtzite structures in small-sized QDs. Furthermore, from differential absorption (DA) spectra, extracted electronic...

Dark excitons in transition-metal dichalcogenides, with their long lifetimes and strong binding energies, provide potential platforms from photonic optoelectronic applications to quantum information science even at room temperature. However, spatial heterogeneity sensitivity strain is not yet understood. Here, we combine tip-enhanced photoluminescence spectroscopy atomic force induced control nanoimage dark WSe2 response local strain. exciton emission facilitated by out-of-plane picocavity...

Exciton-polaritons confined in plasmonic cavities are hybridized light-matter quasiparticles, with distinct optical characteristics compared to plasmons and excitons alone. Here, we demonstrate the electric tunability of a single polaritonic quantum dot operating at room temperature electric-field tip-enhanced strong coupling spectroscopy. For nanoplasmonic tip cavity variable dc local field, dynamically control Rabi frequency corresponding polariton emission, crossing weak coupling. We...

Abstract Quantum state control of two‐level emitters is fundamental for many information processing, metrology, and sensing applications. However, quantum‐coherent photonic solid‐state has traditionally been limited to cryogenic environments, which are not compatible with implementation in scalable, broadly distributed technologies. In contrast, plasmonic nano‐cavities deep sub‐wavelength mode volumes have recently emerged as a path toward room temperature quantum control. optimization,...

We synthesized CsPbBr3 perovskite nanocrystals (NCs) at different reaction temperatures and tracked their growth kinetics on the basis of optical properties estimated size. The energies absorption fluorescence (FL) peaks with increasing temperature for NCs were tuned within regions 2.429–2.570 eV 2.391–2.469 eV, respectively, depending size (9.9–12.5 nm). Stokes shifts NC decreased from 101 meV to 38 meV. full-width half-maximum FL CdSe 150 90 because improved uniformity NCs. energy spacing...

Direct nanoscale 3D patterning of CNT fibers is achieved using a quartz tuning fork-based atomic force microscope with nanopipette, in situ Raman spectroscopy enabling real-time structural monitoring.

Transition-metal dichalcogenide heterostructures are an emergent platform for novel many-body states from exciton condensates to nanolasers. However, their dynamics difficult disentangle due multiple competing processes with time scales varying over many orders of magnitude. Using a configurable nano-optical cavity based on plasmonic scanning probe tip, the radiative (rad) and nonradiative (nrad) relaxation intra- interlayer excitons is controlled. Tuning relative rates in WSe2/MoSe2...

Gap plasmon (GP) resonance in static surface-enhanced Raman spectroscopy (SERS) structures is generally too narrow and not tunable. Here, we present an adaptive gap-tunable SERS device to selectively enhance modulate different vibrational modes via active flexible Au nanogaps, with optical control. The tunability of GP up ∼1200 cm–1 by engineering gap width, facilitated mechanical bending a polyethylene terephthalate substrate. We confirm that the tuned enhances spectral regions molecules....

Transition metal dichalcogenides (TMDs) are promising candidates for ultrathin functional semiconductor devices. In particular, incorporating plasmonic nanoparticles into TMD-based devices enhances the light–matter interaction increased absorption efficiency and enables control of device performance such as electronic, electrical, optical properties. this heterohybrid structure, manipulating number TMD layers aggregate size is a straightforward approach to tailoring performance. study, we...

A quantitative single-molecule tip-enhanced Raman spectroscopy (TERS) study at room temperature remained a challenge due to the rapid structural dynamics of molecules exposed air. Here, we demonstrate hyperspectral TERS imaging single or few brilliant cresyl blue (BCB) temperature, along with spectral analyses. Robust chemical is enabled by freeze-frame approach using thin Al2O3 capping layer, which suppresses diffusions and inhibits reactions contamination in For resolved spatially image,...

Abstract Spatial manipulation of excitonic quasiparticles, such as neutral excitons, charged and interlayer in two-dimensional semiconductors offers unique capabilities for a broad range optoelectronic applications, encompassing photovoltaics, exciton-integrated circuits, quantum light-emitting systems. Nonetheless, their practical implementation is significantly restricted by the absence electrical controllability short lifetime low exciton funneling efficiency at room temperature, which...