A5064875935- Thermal properties of materials
- Advanced Thermoelectric Materials and Devices
- Adhesion, Friction, and Surface Interactions
- Molecular Junctions and Nanostructures
- Thermography and Photoacoustic Techniques
- Force Microscopy Techniques and Applications
- Thermal Radiation and Cooling Technologies
- Surface and Thin Film Phenomena
- Electrocatalysts for Energy Conversion
- Near-Field Optical Microscopy
- Advanced Thermodynamics and Statistical Mechanics
- Arsenic contamination and mitigation
- Mine drainage and remediation techniques
- Fuel Cells and Related Materials
- Risk and Safety Analysis
- Advanced Sensor Technologies Research
- Advanced Battery Technologies Research
- Human-Automation Interaction and Safety
- Occupational Health and Safety Research
- Concrete and Cement Materials Research
- Supramolecular Chemistry and Complexes
- Advanced biosensing and bioanalysis techniques
- Heavy metals in environment
- Semiconductor materials and devices
- Mechanical and Optical Resonators
Incheon National University
2019-2023
Pukyong National University
2020-2023
SK Group (South Korea)
2018
University of Michigan
2012-2015
Korea University
2006-2012
Seoul National University
2004-2011
Yonsei University
2006
Understanding energy dissipation at the nanoscale requires ability to probe temperature fields with nanometer resolution. Here, we describe an ultra-high vacuum (UHV)-based scanning thermal microscope (SThM) technique that is capable of quantitatively mapping ∼15 mK resolution and ∼10 nm spatial In this technique, a custom fabricated atomic force (AFM) cantilever, Au-Cr thermocouple integrated into tip probe, used measure surfaces. Operation in UHV environment eliminates parasitic heat...
Because of its high spatial resolution, scanning thermal microscopy (SThM) has been developed quite actively and applied in such diverse areas as microelectronics, optoelectronics, polymers, carbon nanotubes for more than a decade since the 1990s. However, despite long history application, surprisingly, no quantitative profiling method established yet. This is mostly due to nonlocal nature measurement by conventional SThM: signal measured SThM induced not only from local heat flux through...
Motivated by recent experiments [Lee et al. Nature 498, 209 (2013)], we present here a detailed theoretical analysis of the Joule heating in current-carrying single-molecule junctions. By combining Landauer approach for quantum transport with ab initio calculations, show how electrodes molecular junction is determined its electronic structure. In particular, that general heat not equally dissipated both and it depends on bias polarity (or equivalently current direction). These asymmetries...
Quantitative studies of nanoscale heat dissipation (Joule heating) are essential for advancing nano-science and technology. Joule heating is widely expected to play a critical role in accelerating electromigration induced device failure. However, limitations quantitatively probing temperature fields—with resolution—have hindered elucidation the electromigration. In this work, we use ultra-high vacuum scanning thermal microscopy directly quantify fields nanowires during Our results...
Although scanning thermal microscope has shown the highest spatial resolution in local temperature and thermophysical property measurement, its usefulness been severely limited due to difficulties quantitative measurement. We propose a double scan technique that measures only from heat transfer through tip-sample contact by subtraction of signal air. A rigorous theoretical model for this is derived. The effectiveness measurement demonstrated experimentally.
Recent advances in the physicochemical understanding of thermal transport across molecular junctions single molecules and monolayers are discussed.
Previously, we introduced the double scan technique, which enables quantitative temperature profiling with a scanning thermal microscope (SThM) without distortion arising from heat transfer through air. However, if tip-sample conductance is disturbed due to extremely small size of sample, such as carbon nanotubes, or an abrupt change in topography, then measurement becomes difficult even technique. Here, developed null-point method by one can quantitatively measure sample disturbances...
In this and the following companion articles, authors present 2ω method, a novel ac mode local thermal property imaging technique with nanoscale spatial resolution. To demonstrate use of thermoelectric probe as an active one that can function both heater temperature sensor, develop implement signal measurement technique, which extract signals from thermocouple junction while electrically heating it simultaneously. The principle is explained by steady periodic electrothermal analysis....
Interface engineering based on the design and fabrication of micro/nanostructures has received much attention as an effective way to improve performance polymer electrolyte membrane (PEM) fuel cells while using same materials quantity. Herein, we fabricated spatially hole-array patterned PEMs with different hole depths both plasma etching process a polymeric stencil 40 μm-sized apertures. This novel technological approach exhibited high pattern fidelity over large area controllability in...
Silver nanowires (AgNWs) have shown remarkable potential as materials for transparent conductive electrodes in next-generation flexible devices because of their excellent physical properties. However, despite this advantage, breakdown occurs when AgNWs are exposed to a high temperature and current flow, which has been significant obstacle. Therefore, thorough understanding the based on local thermal electrical analyses is essential developing new various electronic applications. As it...
This paper presents the 2ω method, a newly developed ac mode local thermal property imaging technique with nanoscale spatial resolution. The authors batch-fabricate thermoelectric probe, whose junction size is about 200nm, yield higher than 95%. shortest time constant of probe measured to be 0.72ms. They experimentally demonstrate that method can map out sample by monitoring amplitude signal from thermocouple heated an ac. By comparing images obtained other methods, they also show using...
Scanning thermal probes are widely used for imaging temperature fields with nanoscale resolution, studying near-field radiative heat transport and locally heating samples. In all these applications, it is critical to know the resistance flow within probe contact between sample. Here, we present an approach quantifying aforementioned resistances using picowatt resolution calorimeters. The measured found be in good agreement classical predictions resistance. techniques developed here...
The directed energy deposition (DED) process offers potential advantages, such as a large building space, limited dilutions, narrow heat-affected zones (HAZ) and potentially improved surface properties. Moreover, heat treatments have been reported to significantly improve the properties of as-built sample by modifying microstructure. In this study, influences various combinations heating cryogenic on mechanical performance corrosion resistance DED M789 steel critically investigated....
Thermopower (S) profiling with nanometer resolution is essential for enhancing the thermoelectric figure of merit, ZT, through nanostructuring materials and carrier density in nanoelectronic devices. However, only qualitative impractical methods or techniques low resolutions have been reported thus far. Herein, we develop a quantitative S method resolution, scanning Seebeck microscopy (SSM), batch-fabricate diamond thermocouple probes to apply SSM silicon, which requires contact stress...
The Nafion® electrolyte membrane, which provides a proton pathway, is an essential element in fuel cell systems. Thermal treatment without additional additives widely used to modify the mechanical properties of construct reliable and durable membranes cell. We measured microscopic thermally annealed using atomic force microscopy with two-point method. Furthermore, macroscopic property was investigated through tensile tests. modulus exceeded over all annealing temperature ranges....
This study explored and analyzed the potential of practical use acid mine drainage-treated sludge (AMDS) as a new soil stabilizer for arsenic (As) heavy metals. Various analyses, toxicity evaluations, extraction batch experiments were performed to investigate characteristics AMDS identify main mechanisms fix As metals on in soil. Two types AMDS, copper metal (MMDS) coal (CMDS) four contaminated soils with different pollution scenarios used experiments. ‘Soil A’ D’ mainly Cd, Pb Zn. B’ C’ As....
The authors developed an experimental method that can measure the in-plane thermal conductivity of a thin film and interface conductance between metal strip, simultaneously. This technique, 3ω method, be applied to films with very high such as diamond films. To guarantee reliability measurement, factors causing error were analyzed rigorously. Then, was demonstrated on silicon dioxide nitride valid in experiments performed open atmosphere. They also several chemical vapor deposited different...
The need for a subsurface imaging technique to locate and characterize defects in multidimensional micro- nanoengineered devices has been growing rapidly. We show that heater can be located accurately using the phase lag of thermal wave. deduce absolute is composed four components. Among components, we isolate component directly related position structure periodic heat source. demonstrate estimated from isolated component.
An ac type thermopower measurement technique was suggested and demonstrated with a simple experimental setup. The distribution across silicon p-n junction measured point by at every 10nm, so that it free from the noise due to built-in potential photoionization effects, compared theoretical result. Although this could not follow sharp variation of near junction, identify smooth peak in depletion layer junction.
Advances in silicon technology bring high-performance mobile devices and networks that connect people all over the world. In meantime, data centers with high computational capabilities boost prosperity of social Emerging keep requiring higher density memory, rates for processing large amounts data. However, implementation DRAM is hindered by chip area, causing degradation power distribution network (PDN) yield losses due to probability die defects. This paper presents a 16Gb 3.2Gb/s/pin DDR4...