Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Pico-Watt Scanning Thermal Microscopy for Thermal Energy Transport Investigation in Atomic Materials

ABSTRACT: The thermophysical properties at the nanoscale are key characteristics that determine the operation of nanoscale devices. Additionally, it is important to measure and verify the thermal transfer characteristics with a few nanometer or atomic-scale resolutions, as the nanomaterial research field has expanded with respect to the development of molecular and atomic-scale devices. Scanning thermal microscopy (SThM) is a well-known method for measuring the thermal transfer phenomena with the highest spatial resolution. However, considering the rapid development of atomic materials, the development of an ultra-sensitive SThM for measuring pico-watt (pW) level heat transfer is essential. In this study, to measure molecular- and atomic-scale phenomena, a pico-watt scanning thermal microscopy (pW-SThM) equipped with a calorimeter capable of measuring heat at the pW level was developed. The heat resolution of the pW-SThM was verified through an evaluation experiment, and it was confirmed that the temperature of the metal line heater sample could be quantitatively measured by using the pW-SThM. Finally, we demonstrated that pW-SThM detects ultra-small differences of local heat transfer that may arise due to differences in van der Waals interactions between the graphene sheets in highly ordered pyrolytic graphite. The pW-SThM probe is expected to significantly contribute to the discovery of new heat and energy transfer phenomena in nanodevices and two-dimensional materials that have been inaccessible through experiments.

SUBMITTER: Koo S

PROVIDER: S-EPMC9100069 | biostudies-literature | 2022 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Nanoscale heat transport analysis by scanning thermal microscopy: from calibration to high-resolution measurements.

Project description:Scanning thermal microscopy (SThM) is a powerful technique for thermal characterization. However, one of the most challenging aspects of thermal characterization is obtaining quantitative information on thermal conductivity with nanoscale lateral resolution. We used this technique with the cross-point calibration method to obtain the thermal contact resistance, R c, and thermal exchange radius, b, using thermo-resistive Pd/Si3N4 probes. The cross-point curves correlate the dependence of R c and b with the sample's thermal conductivity. We implemented a 3ω-SThM method in which reference samples with known thermal conductivity were used in the calibration and validation process to guarantee optimal working conditions. We achieved values of R c = 0.94 × 106 ± 0.02 K W-1 and b = 2.41 × 10-7 ± 0.02 m for samples with a low thermal conductivity (between 0.19 and 1.48 W m-1 K-1). These results show a large improvement in spatial resolution over previously reported data for the Wollaston probes (where b ∼ 2.8 μm). Furthermore, the contact resistance with the Pd/Si3N4 is ∼20× larger than reported for a Wollaston wire probe (with 0.45 × 105 K W-1). These thermal parameters were used to determine the unknown thermal conductivity of thermoelectric films of Ag2Se, Ag2-x Se, Cu2Se (smooth vs. rough surface), and Bi2Te3, obtaining, in units of W m-1 K-1, the values of 0.63 ± 0.07, 0.69 ± 0.15, 0.79 ± 0.03, 0.82 ± 0.04, and 0.93 ± 0.12, respectively. To the best of our knowledge, this is the first time these microfabricated probes have been calibrated using the cross-point method to perform quantitative thermal analysis with nanoscale resolution. Moreover, this work shows high-resolution thermal images of the V 1ω and V 3ω signals, which can offer relevant information on the material's heat dissipation.

| S-EPMC9419519 | biostudies-literature

Investigation of thermal energy transport interface of hybrid graphene-carbon nanotube/polyethylene nanocomposites.

Project description:It is well known the thermal properties of three-dimensional (3-D) hybrid graphene (GR)-carbon nanotube (CNT) structures are not superior to that of the individual GR and CNT, however, the 3-D hybrid GR-CNT structures can effectively improve the thermal properties of polymer matrix. Therefore, understanding the thermal energy transport in the interface between polymer matrix and 3-D hybrid GR-CNT structure is essential. Here, the enhancement mechanism of interfacial thermal transport of hybrid GR-CNT structure was explored by applying non-equilibrium molecular dynamics (NEMD) simulations. Three different types of hybrid GR-CNT structures were built. The influences of CNT radius and CNT type for the hybrid GR-CNT on the interfacial thermal properties were also analyzed. Computational results show that among the three different types of hybrid GR-CNT structures, the Model-I, i.e., the covalent bond hybrid GR-CNT structures are of the best interfacial thermal properties. Meanwhile, the CNT radius of hybrid GR-CNT structure has a great influence on the interfacial thermal properties.

| S-EPMC5666017 | biostudies-literature

Atomic structures of silicene layers grown on Ag(111): scanning tunneling microscopy and noncontact atomic force microscopy observations.

Project description:Silicene, the considered equivalent of graphene for silicon, has been recently synthesized on Ag(111) surfaces. Following the tremendous success of graphene, silicene might further widen the horizon of two-dimensional materials with new allotropes artificially created. Due to stronger spin-orbit coupling, lower group symmetry and different chemistry compared to graphene, silicene presents many new interesting features. Here, we focus on very important aspects of silicene layers on Ag(111): First, we present scanning tunneling microscopy (STM) and non-contact Atomic Force Microscopy (nc-AFM) observations of the major structures of single layer and bi-layer silicene in epitaxy with Ag(111). For the (3 × 3) reconstructed first silicene layer nc-AFM represents the same lateral arrangement of silicene atoms as STM and therefore provides a timely experimental confirmation of the current picture of the atomic silicene structure. Furthermore, both nc-AFM and STM give a unifying interpretation of the second layer (?3 × ?3)R ± 30° structure. Finally, we give support to the conjectured possible existence of less stable, ~2% stressed, (?7 × ?7)R ± 19.1° rotated silicene domains in the first layer.

| S-EPMC3739010 | biostudies-literature

Materials characterisation by angle-resolved scanning transmission electron microscopy.

Project description:Solid-state properties such as strain or chemical composition often leave characteristic fingerprints in the angular dependence of electron scattering. Scanning transmission electron microscopy (STEM) is dedicated to probe scattered intensity with atomic resolution, but it drastically lacks angular resolution. Here we report both a setup to exploit the explicit angular dependence of scattered intensity and applications of angle-resolved STEM to semiconductor nanostructures. Our method is applied to measure nitrogen content and specimen thickness in a GaNxAs1-x layer independently at atomic resolution by evaluating two dedicated angular intervals. We demonstrate contrast formation due to strain and composition in a Si- based metal-oxide semiconductor field effect transistor (MOSFET) with GexSi1-x stressors as a function of the angles used for imaging. To shed light on the validity of current theoretical approaches this data is compared with theory, namely the Rutherford approach and contemporary multislice simulations. Inconsistency is found for the Rutherford model in the whole angular range of 16-255?mrad. Contrary, the multislice simulations are applicable for angles larger than 35?mrad whereas a significant mismatch is observed at lower angles. This limitation of established simulations is discussed particularly on the basis of inelastic scattering.

| S-EPMC5111052 | biostudies-literature

Shape-selective transport through rectangle-based molecular materials: thin-film scanning electrochemical microscopy studies.

Project description:Microporous thin films (approximately equal to 50 to 400 nm) composed of discrete, cavity-containing molecular rectangles have been prepared. The films, which contain both amorphous and microcrystalline domains, display shape-selective transport behavior. They are permeable to small molecules and to molecules that are short or narrow in at least one dimension--for example, elongated planar molecules--but are impermeable to molecules lacking a narrow dimension. However, the shape selectivity is based on transport through intramolecular rather than intermolecular cavities. By using redox-active probe molecules, rates of transport through the rectangle-based material have been extracted from electrochemical measurements. Spatially resolved measurements obtained via scanning electrochemical microscopy have permitted transport through individual microcrystals to be evaluated semiquantitatively. The measurements reveal that transport is roughly two orders of magnitude slower than observed with thin microcrystalline films of molecular squares featuring similar-sized cavities. The differences likely reflect the fact that cavities within the square-based materials, but not the rectangle-based material, align to form simple one-dimensional channels.

| S-EPMC122741 | biostudies-other

Atomic number dependence of Z contrast in scanning transmission electron microscopy.

Project description:Annular dark-field (ADF) imaging by scanning transmission electron microscopy (STEM) is a common technique for material characterization with high spatial resolution. It has been reported that ADF signal is proportional to the nth power of the atomic number Z, i.e., the Z contrast in textbooks and papers. Here we first demonstrate the deviation from the power-law model by quantitative experiments of a few 2D materials (graphene, MoS2 and WS2 monolayers). Then we elucidate ADF signal of single atoms using simulations to clarify the cause of the deviation. Two major causes of the deviation from the power-law model will be pointed out. The present study provides a practical guideline for the usage of the conventional power-law model for ADF imaging.

| S-EPMC6098135 | biostudies-literature

Atomic-Scale Patterning of Arsenic in Silicon by Scanning Tunneling Microscopy.

Project description:Over the past two decades, prototype devices for future classical and quantum computing technologies have been fabricated by using scanning tunneling microscopy and hydrogen resist lithography to position phosphorus atoms in silicon with atomic-scale precision. Despite these successes, phosphine remains the only donor precursor molecule to have been demonstrated as compatible with the hydrogen resist lithography technique. The potential benefits of atomic-scale placement of alternative dopant species have, until now, remained unexplored. In this work, we demonstrate the successful fabrication of atomic-scale structures of arsenic-in-silicon. Using a scanning tunneling microscope tip, we pattern a monolayer hydrogen mask to selectively place arsenic atoms on the Si(001) surface using arsine as the precursor molecule. We fully elucidate the surface chemistry and reaction pathways of arsine on Si(001), revealing significant differences to phosphine. We explain how these differences result in enhanced surface immobilization and in-plane confinement of arsenic compared to phosphorus, and a dose-rate independent arsenic saturation density of 0.24 ± 0.04 monolayers. We demonstrate the successful encapsulation of arsenic delta-layers using silicon molecular beam epitaxy, and find electrical characteristics that are competitive with equivalent structures fabricated with phosphorus. Arsenic delta-layers are also found to offer confinement as good as similarly prepared phosphorus layers, while still retaining >80% carrier activation and sheet resistances of <2 kΩ/square. These excellent characteristics of arsenic represent opportunities to enhance existing capabilities of atomic-scale fabrication of dopant structures in silicon, and may be important for three-dimensional devices, where vertical control of the position of device components is critical.

| S-EPMC7146850 | biostudies-literature

Characterization of protein immobilization on nanoporous gold using atomic force microscopy and scanning electron microscopy.

Project description:Nanoporous gold (NPG), made by dealloying low carat gold alloys, is a relatively new nanomaterial finding application in catalysis, sensing, and as a support for biomolecules. NPG has attracted considerable interest due to its open bicontinuous structure, high surface-to-volume ratio, tunable porosity, chemical stability and biocompatibility. NPG also has the attractive feature of being able to be modified by self-assembled monolayers. Here we use scanning electron microscopy (SEM) and atomic force microscopy (AFM) to characterize a highly efficient approach for protein immobilization on NPG using N-hydroxysuccinimide (NHS) ester functionalized self-assembled monolayers on NPG with pore sizes in the range of tens of nanometres. Comparison of coupling under static versus flow conditions suggests that BSA (Bovine Serum Albumin) and IgG (Immunoglobulin G) can only be immobilized onto the interior surfaces of free standing NPG monoliths with good coverage under flow conditions. AFM is used to examine protein coverage on both the exterior and interior of protein modified NPG. Access to the interior surface of NPG for AFM imaging is achieved using a special procedure for cleaving NPG. AFM is also used to examine BSA immobilized on rough gold surfaces as a comparative study. In principle, the general approach described should be applicable to many enzymes, proteins and protein complexes since both pore sizes and functional groups present on the NPG surfaces are controllable.

| S-EPMC3168530 | biostudies-literature

Atomic Force Microscopy on Biological Materials Related to Pathological Conditions.

Project description:Atomic force microscopy (AFM) is an easy-to-use, powerful, high-resolution microscope that allows the user to image any surface and under any aqueous condition. AFM has been used in the investigation of the structural and mechanical properties of a wide range of biological matters including biomolecules, biomaterials, cells, and tissues. It provides the capacity to acquire high-resolution images of biosamples at the nanoscale and allows at readily carrying out mechanical characterization. The capacity of AFM to image and interact with surfaces, under physiologically relevant conditions, is of great importance for realistic and accurate medical and pharmaceutical applications. The aim of this paper is to review recent trends of the use of AFM on biological materials related to health and sickness. First, we present AFM components and its different imaging modes and we continue with combined imaging and coupled AFM systems. Then, we discuss the use of AFM to nanocharacterize collagen, the major fibrous protein of the human body, which has been correlated with many pathological conditions. In the next section, AFM nanolevel surface characterization as a tool to detect possible pathological conditions such as osteoarthritis and cancer is presented. Finally, we demonstrate the use of AFM for studying other pathological conditions, such as Alzheimer's disease and human immunodeficiency virus (HIV), through the investigation of amyloid fibrils and viruses, respectively. Consequently, AFM stands out as the ideal research instrument for exploring the detection of pathological conditions even at very early stages, making it very attractive in the area of bio- and nanomedicine.

| S-EPMC6535871 | biostudies-literature

Atomic species identification at the (101) anatase surface by simultaneous scanning tunnelling and atomic force microscopy.

Project description:Anatase is a pivotal material in devices for energy-harvesting applications and catalysis. Methods for the accurate characterization of this reducible oxide at the atomic scale are critical in the exploration of outstanding properties for technological developments. Here we combine atomic force microscopy (AFM) and scanning tunnelling microscopy (STM), supported by first-principles calculations, for the simultaneous imaging and unambiguous identification of atomic species at the (101) anatase surface. We demonstrate that dynamic AFM-STM operation allows atomic resolution imaging within the material's band gap. Based on key distinguishing features extracted from calculations and experiments, we identify candidates for the most common surface defects. Our results pave the way for the understanding of surface processes, like adsorption of metal dopants and photoactive molecules, that are fundamental for the catalytic and photovoltaic applications of anatase, and demonstrate the potential of dynamic AFM-STM for the characterization of wide band gap materials.

| S-EPMC4491188 | biostudies-literature

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