A5090555401- Graphene research and applications
- Plasmonic and Surface Plasmon Research
- Gold and Silver Nanoparticles Synthesis and Applications
- Carbon Nanotubes in Composites
- Near-Field Optical Microscopy
- Diamond and Carbon-based Materials Research
- 2D Materials and Applications
- Ion-surface interactions and analysis
- Advanced Photocatalysis Techniques
- Quantum Dots Synthesis And Properties
- Mechanical and Optical Resonators
- MXene and MAX Phase Materials
- Nanowire Synthesis and Applications
- Molecular Junctions and Nanostructures
- Nanoparticles: synthesis and applications
- Thermal properties of materials
- Electrochemical sensors and biosensors
- Carbon and Quantum Dots Applications
- Graphene and Nanomaterials Applications
- Semiconductor Quantum Structures and Devices
- Integrated Circuits and Semiconductor Failure Analysis
- Electrochemical Analysis and Applications
- Laser-Ablation Synthesis of Nanoparticles
- Force Microscopy Techniques and Applications
- Calcium Carbonate Crystallization and Inhibition
Instituto Nacional de Metrologia, Qualidade e Tecnologia
2013-2023
Universidade Federal de Minas Gerais
2013-2015
The growing demand for petroleum products and the natural decline of well's pressure during oil production turned industry's focus onto development improvement enhanced recovery (EOR) techniques. Nanotechnology nanomaterials may increase rates through nanofluid flooding applications. In this scenario, a containing Fe3O4 nanoparticles (NPs) with ability to carry surfactants such as cetyltrimethylammonium bromide (CTAB) was synthesized; synergistic effect observed when used wettability...
A reproducible route for tuning localized surface plasmon resonance in scattering type near-field optical microscopy probes is presented. The method based on the production of a focused-ion-beam milled single groove near apex electrochemically etched gold tips. Electron energy-loss spectroscopy and scanning transmission electron are employed to obtain highly spatially spectroscopically resolved maps probes, revealing at visible near-infrared wavelengths. By changing distance L between probe...
Abstract Squeezing optical fields into nanometer scale is the key step to perform spatially resolved near‐field optics. In scattering‐type microscopy, this task accomplished by nanoantennas that convert propagating radiation local near‐fields and vice versa. The usual nanoantenna composed an elongated metal structure whose longitudinal dimension scaled support dipole modes of localized surface plasmon resonances. However, monopole can also be explored if nanoparticle electrically grounded on...
The knowledge of the phonon coherence length is great importance for two-dimensional-based materials since phonons can limit lifetime charge carriers and heat dissipation. Here we use tip-enhanced Raman spectroscopy (TERS) to measure spatial correlation Lc A1g1 A1g2 monolayer few-layer gallium sulfide (GaS). differences in values are responsible different enhancements A1g modes, with always enhancing more than A1g2, independently number GaS layers. For five layers, results show an 64 47 nm...
We investigate the anti-Stokes Raman scattering of single carbyne chains confined inside double-walled carbon nanotubes. Individual are identified using tip-enhanced (TERS) and heated by resonant excitation with varying laser powers. study temperature dependence carbyne's spectrum quantify laser-induced heating based on anti-Stokes/Stokes ratio. Due to its molecular size large cross section, holds great promise for local monitoring, potential applications ranging from nanoelectronics biology.
Titanate nanotubes were synthesized and subjected to an ion exchange reaction with erbium salt aqueous solution obtain titanate exchanged (3+) ions. In order evaluate the effects of thermal treatment atmosphere on structural optical properties nanotubes, we them heat in air argon atmospheres. For comparison, also treated same conditions. A complete characterizations samples was performed. The evidenced preservation morphology presence phases oxides decorating surface nanotubes. Variations...
Coherence length (Lc) of the Raman scattering process in graphene as a function Fermi energy is obtained with spatially coherent tip-enhanced spectroscopy. Lc decreases when moved into neutrality point, consistent concept Kohn anomaly within ballistic transport regime. Since involves electrons and phonons, observed results can be rationalized either due to unusually large variation longitudinal optical phonon group velocity vg, reaching twice value for acoustic phonon, or changes electron...
The role of plasmon resonance on the optical efficiency nanoantennas for tip-enhanced Raman spectroscopy (TERS) is reviewed. Technical details surface polaritons (SPP), localized (LSPR), and gap mode are provided. Nanotechnology engineering necessary to adequate nanoantenna's size, shape composition match conditions with exciting radiation source. Computational simulation guides development new types plasmonic different materials morphologies, specially designed reach target applications. An...
Carbyne, a linear chain of carbon atoms, is the truly one-dimensional allotrope and strongest known Raman scatterer. Here, we use tip-enhanced scattering (TERS) to further enhance response single carbyne confined inside double-walled nanotube. We observe an increase anti-Stokes by factor 3290 22-fold enhancement anti-Stokes/Stokes ratio relative far-field measurements. The power dependence under TERS conditions indicative coherent Stokes–anti-Stokes mediated excited phonon. role resonance...
Abstract We systematically investigate the influence of polyvinyl formal (PVFM), commonly known as Formvar, in comparison to polycarbonate (PC) and polymethyl methacrylate (PMMA), encapsulation materials on strain performance MoS 2 monolayer bilayer flakes flexible polypropylene (PP) substrates. Notably, optical differential reflectance measurements reveal that PVFM PMMA significantly enhances mechanical thermal gauge factors by approximately 2-fold (up ~-50 meV/%) 6-fold ~-1.5 meV/°C),...
On nanomaterials characterization, the evolution from broadly utilized micro-Raman spectroscopy to a nanoscale regime is taking place with improvements in tip-enhanced Raman (TERS). It not clear, however, which extent protocols developed within diffraction-limited far-field configuration apply near-field regime. Defects graphene nanoflakes are investigated this work both micro and nano regimes, showing that characteristics quantify defects actually change presence of TERS tip, generating...
Tip-enhanced Raman spectroscopy (TERS) has reached nanometer spatial resolution for measurements performed at ambient conditions and subnanometer ultrahigh vacuum. Super-resolution (beyond the tip apex diameter) TERS been obtained mostly in gap mode configuration, where a conductive substrate localizes electric fields. Here we present experimental theoretical to explore field distribution responsible spectral enhancement. We use gold tips of 40±10nm diameter measure on graphene, spatially...
Understanding the impact of doping variations on physical properties two-dimensional materials is important for their application in electronic and optoelectronic devices. Here we report a nano-optical study graphene MoS2 homojunctions by placing these two partly top layered talc substrate, an SiO2 substrate. By analyzing nano-Raman scattering from nanophotoluminescense emission MoS2, different zones are evident with sub-100 nm wide charge oscillations. The oscillations occur abruptly at...
Hybrid diamond–graphite nanoplatelet (DGNP) thin films are produced and applied to label-free impedimetric biosensors for the first time, using avidin detection as a proof of concept. The DGNPs synthesized by microwave plasma chemical vapor deposition through H2/CH4/N2 gas mixtures in reproducible rapid single-step process. material building unit consists an inner two-dimensional-like nanodiamond with preferential vertical alignment covered covalently bound nanocrystalline graphite grains,...
Plasmonic nanoantennas are pushing the limits of optical imaging resolution capabilities in near-field scanning microscopy (NSOM). Accordingly, these techniques driving basic understanding photonic and optoelectronic nanoscale devices with applications sensing, energy conversion, solid-state lighting, information technology. Imaging localized surface plasmon resonance (LSPR) at is a key to responses given tip geometry order engineer better plasmonic for experiments. In recent years...
For tip‐enhanced Raman spectroscopy (TERS), the recently developed plasmon‐tunable tip pyramid, composed of a gold micropyramidal body with nanopyramid end, makes it possible to obtain spectral enhancements in 2D systems up two orders magnitude higher than what is found literature. Herein, optical properties these tips are explored, including field‐enhancement dependence on edge length ( L ), its apex diameter D tip–sample distance Z and presence metallic micropyramid body. The study shown...
Abstract The use of nano-Raman spectroscopy to study two-dimensional (2D) systems is presented here. nano (tip-enhanced) Raman technique briefly introduced, addressing some new theoretical aspects for in the near-field regime, including field coherence, distribution and relevance atomic description quenching effects. State-of-the-art results graphene transition metal dichalcogenides are presented, exploring connection between micro- metrology. Various such as defects, homojunctions,...
Crystalline carbon-based materials are intrinsically chemically inert and good heat conductors, allowing their applications in a great variety of devices. A technological step forward dissipators production can be given by tailoring the carbon phase microstructure, tuning CVD synthesis conditions. In this work, rapid bottom-up vertically aligned hybrid material comprising diamond thin platelets covered crystalline graphite layer was developed. single run designed order to produce high aspect...