Browse
Submit Data
Databases
API
Help

Dataset Information

22 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Thermal manipulation of plasmons in atomically thin films.

ABSTRACT: Nanoscale photothermal effects enable important applications in cancer therapy, imaging and catalysis. These effects also induce substantial changes in the optical response experienced by the probing light, thus suggesting their application in all-optical modulation. Here, we demonstrate the ability of graphene, thin metal films, and graphene/metal hybrid systems to undergo photothermal optical modulation with depths as large as >70% over a wide spectral range extending from the visible to the terahertz frequency domains. We envision the use of ultrafast pump laser pulses to raise the electron temperature of graphene during a picosecond timescale in which its mid-infrared plasmon resonances undergo dramatic shifts and broadenings, while visible and near-infrared plasmons in the neighboring metal films are severely attenuated by the presence of hot graphene electrons. Our study opens a promising avenue toward the active photothermal manipulation of the optical response in atomically thin materials with potential applications in ultrafast light modulation.

SUBMITTER: Dias EJC

PROVIDER: S-EPMC7235028 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Atomically Thin, Optically Isotropic Films with 3D Nanotopography.

Project description:Flat optics aims for the on-chip miniaturization of optical systems for high-speed and low-power operation, with integration of thin and lightweight components. Here, we present atomically thin yet optically isotropic films realized by using three-dimensional (3D) topographic reconstruction of anisotropic two-dimensional (2D) films to balance the out-of-plane and in-plane optical responses on the subwavelength scale. We achieve this by conformal growth of monolayer transition metal dichalcogenide (TMD) films on nanodome-structured substrates. The resulting films show an order-of-magnitude increase in the out-of-plane susceptibility for enhanced angular performance, displaying polarization isotropy in the off-axis absorption, as well as improved photoluminescence emission profiles, compared to their flat-film counterparts. We further show that such 3D geometric programming of optical properties is applicable to different TMD materials, offering spectral generalization over for the entire visible range. Our approach presents a powerful platform for advancing the development of atomically thin flat optics with custom-designed light-matter interactions.

| S-EPMC8431725 | biostudies-literature

Exciton-dominated Dielectric Function of Atomically Thin MoS2 Films.

Project description:We systematically measure the dielectric function of atomically thin MoS2 films with different layer numbers and demonstrate that excitonic effects play a dominant role in the dielectric function when the films are less than 5-7 layers thick. The dielectric function shows an anomalous dependence on the layer number. It decreases with the layer number increasing when the films are less than 5-7 layers thick but turns to increase with the layer number for thicker films. We show that this is because the excitonic effect is very strong in the thin MoS2 films and its contribution to the dielectric function may dominate over the contribution of the band structure. We also extract the value of layer-dependent exciton binding energy and Bohr radius in the films by fitting the experimental results with an intuitive model. The dominance of excitonic effects is in stark contrast with what reported at conventional materials whose dielectric functions are usually dictated by band structures. The knowledge of the dielectric function may enable capabilities to engineer the light-matter interactions of atomically thin MoS2 films for the development of novel photonic devices, such as metamaterials, waveguides, light absorbers, and light emitters.

| S-EPMC4657050 | biostudies-literature

Directed self-assembly of block copolymer films on atomically-thin graphene chemical patterns.

Project description:Directed self-assembly of block copolymers is a scalable method to fabricate well-ordered patterns over the wafer scale with feature sizes below the resolution of conventional lithography. Typically, lithographically-defined prepatterns with varying chemical contrast are used to rationally guide the assembly of block copolymers. The directed self-assembly to obtain accurate registration and alignment is largely influenced by the assembly kinetics. Furthermore, a considerably broad processing window is favored for industrial manufacturing. Using an atomically-thin layer of graphene on germanium, after two simple processing steps, we create a novel chemical pattern to direct the assembly of polystyrene-block-poly(methyl methacrylate). Faster assembly kinetics are observed on graphene/germanium chemical patterns than on conventional chemical patterns based on polymer mats and brushes. This new chemical pattern allows for assembly on a wide range of guiding periods and along designed 90° bending structures. We also achieve density multiplication by a factor of 10, greatly enhancing the pattern resolution. The rapid assembly kinetics, minimal topography, and broad processing window demonstrate the advantages of inorganic chemical patterns composed of hard surfaces.

| S-EPMC4985650 | biostudies-literature

Optical manipulation of work function contrasts on metal thin films.

Project description:Work function is a crucial metric in every optoelectronic device to ensure a specific charge transport scheme. However, the number of stable conductive materials available in a given work function range is scant, necessitating work function modulation. As opposed to all the previous chemical methods of work function modulation, we introduce here an alternative approach involving optical modulation. The work function is the minimum energy needed to eject an electron from a solid into vacuum and is known to be light-intensity-independent. A "light intensity dependent" change in work function was observed in metallic thin films coated on a semiconductor. This new phenomenon, contrasting the existing notions on work function, was tested and affirmed with three different systems, namely, Au/n-Si, Pt/n-Si, and W/n-Si. A work function shift of 0.22 eV is achieved in the Pt/n-Si system merely by tuning the illumination intensity from 0 to 18 mW/cm2. Continuous tuning of work functions to a specified range is now possible just by tuning the light intensity with a few discrete metals in hand. Moreover, selective illumination creates a work function contrast on the metal film, enabling in-plane charge transport. This throws new light on the design and understanding of the optoelectronic devices. In light of this, we also present a simple photodetector design that is sensitive to illumination direction.

| S-EPMC5837426 | biostudies-literature

Probing interlayer shear thermal deformation in atomically-thin van der Waals layered materials.

Project description:Atomically-thin van der Waals layered materials, with both high in-plane stiffness and bending flexibility, offer a unique platform for thermomechanical engineering. However, the lack of effective characterization techniques hinders the development of this research topic. Here, we develop a direct experimental method and effective theoretical model to study the mechanical, thermal, and interlayer properties of van der Waals materials. This is accomplished by using a carefully designed WSe2-based heterostructure, where monolayer WSe2 serves as an in-situ strain meter. Combining experimental results and theoretical modelling, we are able to resolve the shear deformation and interlayer shear thermal deformation of each individual layer quantitatively in van der Waals materials. Our approach also provides important interlayer coupling information as well as key thermal parameters. The model can be applied to van der Waals materials with different layer numbers and various boundary conditions for both thermally-induced and mechanically-induced deformations.

| S-EPMC9271035 | biostudies-literature

Layer matching epitaxy of NiO thin films on atomically stepped sapphire (0001) substrates.

Project description:Thin-film epitaxy is critical for investigating the original properties of materials. To obtain epitaxial films, careful consideration of the external conditions, i.e. single-crystal substrate, temperature, deposition pressure and fabrication method, is significantly important. In particular, selection of the single-crystal substrate is the first step towards fabrication of a high-quality film. Sapphire (single-crystalline α-Al2O3) is commonly used in industry as a thin-film crystal-growth substrate, and functional thin-film materials deposited on sapphire substrates have found industrial applications. However, while sapphire is a single crystal, two types of atomic planes exist in accordance with step height. Here we discuss the need to consider the lattice mismatch for each of the sapphire atomic layers. Furthermore, through cross-sectional transmission electron microscopy analysis, we demonstrate the uniepitaxial growth of cubic crystalline thin films on bistepped sapphire (0001) substrates.

| S-EPMC4585880 | biostudies-other

Thermal expansion behavior of thin films expanding freely on water surface.

Project description:Coefficient of thermal expansion (CTE) for thin film has been measured only from change in thickness because thin film has to be constrained on a solid substrate. However, thin film CTE shows different values depending on the supporting solid substrate. Here, a novel measurement method is suggested to quantitatively measure the in-plane thermal expansion of thin films floating on a water surface. In-plane thermal expansion of thin films on water surface is achieved by heating the water. The CTE is measured through a digital image correlation (DIC) technique. The DIC tracks displacement marks deposited on the film surface, and the in-plane thermal strain is defined as the change in distance between the patterns. The method can be applied to measure the CTE of polymer, metal, and graphene with a thickness ranging from a micrometer to one-atom-thickness. The in-plane thermal expansion of the polystyrene (PS) thin film decreased as the film thickness decreased. The negative CTE of graphene is also successfully explored without any substrate effects or complicated calculations. The CTE measurement method can provide understanding of the intrinsic thermal expansion behavior of thin films including emerging two-dimensional materials.

| S-EPMC6506477 | biostudies-literature

Probing the role of an atomically thin SiNx interlayer on the structure of ultrathin carbon films.

Project description:Filtered cathodic vacuum arc (FCVA) processed carbon films are being considered as a promising protective media overcoat material for future hard disk drives (HDDs). However, at ultrathin film levels, FCVA-deposited carbon films show a dramatic change in their structure in terms of loss of sp3 bonding, density, wear resistance etc., compared to their bulk counterpart. We report for the first time how an atomically thin (0.4 nm) silicon nitride (SiNx) interlayer helps in maintaining/improving the sp3 carbon bonding, enhancing interfacial strength/bonding, improving oxidation/corrosion resistance, and strengthening the tribological properties of FCVA-deposited carbon films, even at ultrathin levels (1.2 nm). We propose the role of the SiNx interlayer in preventing the catalytic activity of Co and Pt in media, leading to enhanced sp3C bonding (relative enhancement~40%). These findings are extremely important in view of the atomic level understanding of structural modification and the development of high density HDDs.

| S-EPMC4028925 | biostudies-literature

Vapor-phase-synthesized fluoroacrylate polymer thin films: thermal stability and structural properties.

Project description:In this study, the thermal, chemical and structural stability of 1H,1H,2H,2H-perfluorodecyl acrylate polymers (p-PFDA) synthetized by initiated chemical vapor deposition (iCVD) were investigated. PFDA polymers are known for their interesting crystalline aggregation into a lamellar structure that induces super-hydrophobicity and oleophobicity. Nevertheless, when considering applications which involve chemical, mechanical and thermal stresses, it is important to know the limits under which the crystalline aggregation and the resulting polymer properties are stable. For this, chemical, morphological and structural properties upon multiple heating/cooling cycles were investigated both for linear PFDA polymers and for differently strong cross-linked alterations thereof. Heat treatment leaves the chemical composition of the linear PFDA polymers largely unchanged, while a more ordered crystalline structure with smoother morphology is observed. At the same time, the hydrophobicity and the integrity of the polymer deteriorate upon heating. The integrity and hydrophobicity of cross-linked p-PFDA films was preserved likely because of the lack of internal strain due to the coexistence of both crystalline and amorphous phases. The possibility to finely tune the degree of cross-linking can therefore expand the application portfolio in which PFDA polymers can be utilized.

| S-EPMC5433210 | biostudies-literature

Neuromorphic Electro-Stimulation Based on Atomically Thin Semiconductor for Damage-Free Inflammation Inhibition

Project description:Inflammation, caused by accumulation of inflammatory cytokines from immunocytes, is prevalent in a variety of diseases. Electro-stimulation emerges as a promising candidate for inflammatory inhibition. Although electroacupuncture is free from surgical injury, it faces the challenges of imprecise pathways/current spikes, and insufficiently defined mechanisms, while non-optimal pathway or spike would require high current amplitude, which makes electro-stimulation usually accompanied by damage and complications. Here, we propose a neuromorphic electro-stimulation based on atomically thin semiconductor floating-gate memory interdigital circuit. Direct stimulation is achieved by wrapping sympathetic chain with flexible electrodes and floating-gate memory are programmable to fire bionic spikes, thus minimizing nerve damage. A substantial decrease (73.5%) in inflammatory cytokine IL-6 occurred, which also enabled better efficacy than commercial stimulator at record-low currents with damage-free to sympathetic neurons. Additionally, using transgenic mice, the anti-inflammation effect is determined by β2 adrenergic signaling from myeloid cell lineage (monocytes/macrophages and granulocytes).

2024-01-20 | GSE253300 | GEO

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data