A5006802194- 2D Materials and Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Graphene research and applications
- Plasmonic and Surface Plasmon Research
- Perovskite Materials and Applications
- MXene and MAX Phase Materials
- Near-Field Optical Microscopy
- Spectroscopy Techniques in Biomedical and Chemical Research
- Advanced biosensing and bioanalysis techniques
- Force Microscopy Techniques and Applications
- GaN-based semiconductor devices and materials
- Electrochemical Analysis and Applications
- Surface and Thin Film Phenomena
- Nanowire Synthesis and Applications
- Spectroscopy and Quantum Chemical Studies
- Electron and X-Ray Spectroscopy Techniques
- Integrated Circuits and Semiconductor Failure Analysis
- Protein Interaction Studies and Fluorescence Analysis
- Molecular Junctions and Nanostructures
- Surface Chemistry and Catalysis
- Semiconductor Quantum Structures and Devices
- Luminescence and Fluorescent Materials
- Diamond and Carbon-based Materials Research
Horiba (Japan)
2025
Nova Measuring Instruments (United States)
2018-2024
NOVA Scientific (United States)
2018-2023
Pacific Northwest National Laboratory
2021
Marin Community Foundation
2017
MXenes are among the most widely researched materials due to a unique combination of high electronic conductivity and hydrophilic surface, confined in 2D structure. Therefore, comprehensive characterization individual MXene flakes is great importance. Here we report on nanoscale Raman imaging single-layer few-layer Ti3C2Tx deposited gold substrate using tip-enhanced scattering (TERS). TERS spectra monolayers dominated by an intense peak at around 201 cm-1 two well-defined peaks 126 725 cm-1....
Gold-mediated exfoliation of MoS2 has attracted considerable interest in the recent years. A strong interaction between and Au facilitates preferential production centimeter-sized monolayer with near-unity yield provides a heterostructure system noteworthy from fundamental standpoint. However, little is known about detailed nature MoS2-Au its evolution thickness. Here, we identify specific vibrational binding energy fingerprints such using Raman X-ray photoelectron spectroscopy, which...
Abstract Visualising the distribution of structural defects and functional groups present on surface two-dimensional (2D) materials such as graphene oxide challenges sensitivity spatial resolution most advanced analytical techniques. Here we demonstrate mapping a carboxyl-modified (GO–COOH) with ≈10 nm using tip-enhanced Raman spectroscopy (TERS). Furthermore, extend capability TERS by measuring local electronic properties in situ, addition to topography chemical composition. Our results...
Abstract The ability to control the density and spatial distribution of substitutional dopants in semiconductors is crucial for achieving desired physicochemical properties. Substitutional doping with adjustable levels has been previously demonstrated 2D transition metal dichalcogenides (TMDs); however, dopant remains an open field. In this work, edge termination as important characteristic TMD monocrystals that affects dopants. Particularly, chemical vapor deposition (CVD)‐grown monolayer...
Understanding growth, grain boundaries (GBs), and defects of emerging two-dimensional (2D) materials is key to enabling their future applications. For quick, nondestructive metrology, many studies rely on confocal Raman spectroscopy, the spatial resolution which constrained by diffraction limit (∼0.5 μm). Here we use tip-enhanced spectroscopy (TERS) for first time synthetic MoSe2 monolayers, combining it with other scanning probe microscopy (SPM) techniques, all sub-20 nm resolution. We...
2D transition metal dichalcogenides (TMDs) are commonly grown by chemical vapor deposition using oxides as solid precursors. Despite the widespread use of this technique, challenges in reproducibility, coverage, and material quality pervasive, suggestive unknown uncontrolled process parameters. In communication, we demonstrate impact water on growth process. Our results show a direct correlation between gas phase content morphology TMD films. particular, that presence enhances...
Chalcogenide perovskites, such as BaZrS3, are emerging semiconductors with the potential for high photovoltaic power conversion efficiency. The role of defects in efficiency generation and collection photoexcited carriers has not been experimentally investigated extensively. We studied effect processing-induced on photoconductive properties single crystals BaZrS3. achieved Ohmic contacts to BaZrS3 observed positive surface photovoltage, which is typically p-type semiconductors. However,...
Supramolecular ordering of organic semiconductors is the key factor defining their electrical characteristics. Yet, it extremely difficult to control, particularly at interface with metal and dielectric surfaces in semiconducting devices. We have explored growth n-type films based on hydrogen-bonded monoalkylnaphthalenediimide (NDI-R) from solution through vapor deposition both conductive insulating surfaces. combined scanning tunneling atomic force microscopies X-ray diffraction analysis...
Tip-enhanced Raman spectroscopy (TERS) is particularly sensitive to analytes residing at plasmonic tip–sample nanojunctions, where the incident and scattered optical fields may be localized optimally enhanced. However, enhanced local electric in this so-called gap-mode TERS configuration are nominally orthogonal sample plane. As such, any given active vibrational eigenstate needs have projections (of its polarizability derivative tensor elements) along normal detectable via TERS. The faint...
We revisit the reductive coupling of p-nitrothiophenol (NTP) to form dimercaptoazobenzene (DMAB), herein monitored through gap-mode tip-enhanced Raman spectroscopy (TERS) and nanoimaging. employ a plasmonic Au probe (100 nm diameter at its apex) illuminated with 633 laser source (50 μW/μm2 sample position) image an NTP-coated faceted silver nanoparticle (∼70 diameter). A detailed analysis recorded spectra reveals that anionic NTP species contribute spectral images, in addition more...
When layers of van der Waals materials are deposited via exfoliation or viscoelastic stamping, nanobubbles sometimes created from aggregated trapped fluids. Though they can be considered a nuisance, have attracted scientific interest in their own right owing to ability generate large in-plane strain gradients that lead rich optoelectronic phenomena, especially the semiconducting transition metal dichalcogenides. Determination within nanobubbles, which is crucial understanding these effects,...
Detailed structural characterization of novel two-dimensional materials plays a key role in understanding their properties and designing optoelectronic devices. High resolution spatial imaging is important for characterizing defects, edges, grain boundaries. We use tip-enhanced Raman scattering (TERS) to obtain nanoscale vibrational images monolayer few-layer MoS <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . compare near-field...
Two-dimensional (2D) transition-metal dichalcogenides (TMDCs) have been explored for many optoelectronic applications. Most of these applications require them to be on insulating substrates. However, fundamental property characterizations, such as mapping surface potential or conductance, substrates are nonideal they lead charging and doping effects impose the inhomogeneity their charge environment atomically thin 2D layers. Here, we report a simple method residue-free dry transfer TMDC...
Classical versus quantum plasmons are responsible for the recorded signals in non-contact-mode contact-mode tip-enhanced Raman spectroscopy (TERS) and lead to distinct observables. Under otherwise identical experimental conditions, we illustrate concept through tapping- TERS mapping of chemically functionalized silver nanocubes. Whereas molecular charging, chemical transformations, optical rectification prominent observables TERS, same effects suppressed using tapping-mode feedback. In...
Abstract Second harmonic generation (SHG) is a nonlinear optical response arising exclusively from broken inversion symmetry in the electric‐dipole limit. Recently, SHG has attracted widespread interest as versatile and noninvasive tool for characterization of crystal emerging ferroic or topological orders quantum materials. However, conventional far‐field optics unable to probe local at deep subwavelength scale. Here, near‐field imaging 2D semiconductors heterostructures with spatial...
Chemical transformations near plasmonic metals have attracted increasing attention in the past few years. Specifically, reactions occurring within nanojunctions that can be detected via surface and tip-enhanced Raman (SER TER) scattering were focus of numerous reports. In this context, even though transition between localized nonlocal (quantum) plasmons at is documented, its implications on chemistry remain poorly understood. We explore latter through AFM-TER-current measurements. use two...
While extensive research effort has been devoted to the study of 2D semiconductor–insulator interfaces in transition metal dichalcogenides (TMDCs), there is little knowledge about electronic quality semiconductor–metal interface atomically thin limit. Here, we present first correlated nanoscale mapping WSe2 with noble metals using co-localized scanning probe microscopy and tip-enhanced optical spectroscopy (TEOS), such as Raman (TERS). Nanoscale maps topography, surface potential, spectra,...
Transition metal dichalcogenides (TMDs) offer exceptional platforms to study unique phenomena in two-dimensional (2D) materials. The understanding of phonon interactions atomically thin TMDs is crucial for the development novel applications. However, advancing our knowledge on dynamics under optical, thermal, electric, and strain perturbations requires comprehensive minimally invasive chemical imaging techniques with nanoscale spatial resolution. Tip-enhanced Raman scattering (TERS) provides...
We demonstrate fast (0.25 s/pixel) nanoscale chemical imaging in aqueous solution via tip-enhanced Raman scattering (TERS), with sub-15 nm spatial resolution. The substrate consists of 4-mercaptobenzonitrile-functionalized monocrystalline gold triangular platelets immersed H2O, which we map using a gold-coated atomic force microscopy probe illuminated by 633 laser source. find that the recorded TERS images trace enhanced local optical fields are sustained toward edges and corners triangles....
The nature of the interface in lateral heterostructures 2D monolayer semiconductors including its composition, size, and heterogeneity critically impacts functionalities it engenders on system for next-generation optoelectronics. Here, we use tip-enhanced Raman scattering (TERS) to characterize a single-layer MoS2/WS2 heterostructure with spatial resolution 50 nm. Resonant nonresonant TERS spectroscopies reveal that is alloyed size varies over an order magnitude─from 600 nm─within single...
We studied the properties of TaSe 3− δ quasi-1D nanoribbons using tip-enhanced Raman scattering (TERS), photoluminescence, and electrical transport measurements. The results show shifts from metallic to semiconductor at higher Se deficiencies.
The interplay between excitons and phonons governs the optical electronic properties of transition metal dichalcogenides (TMDs). Even though a number linear nonlinear optical-, electron-, photoelectron-based approaches have been developed and/or adopted to characterize in single/few-layer TMDs their heterostructures, no existing method is capable directly probing ultralow-frequency interlayer on nanoscale. To this end, we tip-enhanced Raman spectroscopy, which allows spectrally spatially...