A5078091245- Thermal properties of materials
- Thermal Radiation and Cooling Technologies
- Thermography and Photoacoustic Techniques
- Heat Transfer and Optimization
- Advanced Thermoelectric Materials and Devices
- Heat Transfer and Boiling Studies
- Graphene research and applications
- Ga2O3 and related materials
- Electronic and Structural Properties of Oxides
- Machine Learning in Materials Science
- 2D Materials and Applications
- Thin-Film Transistor Technologies
- Spacecraft and Cryogenic Technologies
- Diamond and Carbon-based Materials Research
- ZnO doping and properties
- Composite Material Mechanics
- Ferroelectric and Piezoelectric Materials
- Geothermal Energy Systems and Applications
- Metal and Thin Film Mechanics
- Semiconductor Quantum Structures and Devices
- GaN-based semiconductor devices and materials
- Quantum and electron transport phenomena
- Semiconductor materials and devices
- Thermal and Kinetic Analysis
- Advanced Sensor Technologies Research
Huazhong University of Science and Technology
2018-2025
University of Pittsburgh
2019-2023
Huazhong University of Science and Technology Hospital
2023
Pittsburgh Quantum Institute
2022
University of Colorado Boulder
2017-2019
National University of Singapore
2001-2018
University of Colorado System
2017
Measuring thermal properties of materials is not only fundamental importance in understanding the transport processes energy carriers (electrons and phonons solids) but also practical interest developing novel with desired for applications conversion storage, electronics, photonic systems. Over past two decades, ultrafast laser-based time-domain thermoreflectance (TDTR) has emerged evolved as a reliable, powerful, versatile technique to measure wide range bulk thin film their interfaces....
Transition metal dichalcogenides (TMDs) are a group of layered 2D semiconductors that have shown many intriguing electrical and optical properties. However, the thermal transport properties in TMDs not well understood due to challenges characterizing anisotropic conductivity. Here, variable-spot-size time-domain thermoreflectance approach is developed simultaneously measure both in-plane through-plane conductivity four kinds (MoS2 , WS2 MoSe2 WSe2 ) over wide temperature range, 80-300 K....
It is challenging to characterize thermal conductivity of materials with strong anisotropy. In this work, we extend the time-domain thermoreflectance (TDTR) method a variable spot size approach simultaneously measure in-plane (Kr) and through-plane (Kz) We first determine Kz from measurement using larger size, when heat flow mainly one-dimensional along direction, measured signals are sensitive only Kz. then extract Kr second same modulation frequency but smaller becomes three-dimensional,...
β-Ga2O3 has attracted considerable interest in recent years for high power electronics, where the thermal properties of play a critical role. The conductivity is expected to be three-dimensionally (3D) anisotropic due monoclinic lattice structure. In this work, 3D tensor (010)-oriented single crystal was measured using recently developed elliptical-beam time-domain thermoreflectance method. Thermal along any direction (010) plane as well one perpendicular can directly measured, from which...
Hexagonal boron nitride (h-BN) has received great interest in recent years as a wide bandgap analog of graphene-derived systems. However, the thermal transport properties h-BN, which can be critical for device reliability and functionality, are little studied both experimentally theoretically. The primary challenge experimental measurements anisotropic conductivity h-BN is that typically sample size single crystals too small conventional measurement techniques, state-of-the-art technologies...
Thermal management has become a crucial issue for the rapid development of electronic devices, and thermal interface materials (TIMs) play an important role in improving heat dissipation. Recently, carbon−based TIMs, including graphene, reduced graphene oxide, carbon nanotubes (CNTs) with high conductivity, have attracted great attention. In this work, we provide graphene−carbon nanotube composite films improved electrical conductivities. The were prepared from mixed oxide (GO) CNT solutions...
The rapid development of high power density devices requires more efficient heat dissipation.
The increasing complexity of advanced materials with anisotropic thermal properties necessitates more generic and efficient methods to determine three-dimensional (3D) conductivity tensors up six independent components. Current rely on a vector-based framework that can handle only four components, often leading inefficiencies inaccuracies. We introduce Three-Dimensional Spatially Resolved Lock-In Micro-Thermography (3D SR-LIT), novel optical characterization technique combining 3D...
Accurate thermal property measurements of multilayer heterostructures, especially in wide-bandgap semiconductor devices, are essential for optimizing device performance. While traditional methods, such as Time-Domain Thermoreflectance (TDTR) and Frequency-Domain (FDTR), effective thin films interfaces, they encounter challenges with complex heterostructures. This paper presents an optical Square-Pulsed Source (SPS) method comprehensive By combining the advantages TDTR FDTR, SPS technique...
Abstract Point defects typically reduce the thermal conductivity ( κ ) of a crystal due to increased scattering heat‐carrying phonons, mechanism that is well understood and widely used enhance or impede heat transfer in material for different applications. Here an opposite effect reported where introduction point graphite with energetic particle irradiation increases its cross‐plane by nearly factor two, from 10.8 18.9 W m K −1 at room temperature. Integrated differential phase contrast...
Materials lacking in-plane symmetry are ubiquitous in a wide range of applications such as electronics, thermoelectrics, and high-temperature superconductors, all which the thermal properties materials play critical part. However, very few experimental techniques can be used to measure anisotropic conductivity. A beam-offset method based on time-domain thermoreflectance (TDTR) was previously proposed detailed analysis is still lacking. Our shows that uncertainties large if laser spot size or...
Transition metal dichalcogenide (TMD) alloys have attracted great interests in recent years due to their tunable electronic properties, especially the semiconductor-metal phase transition, along with potential applications solid-state memories and thermoelectrics. However, thermal conductivity of layered two-dimensional (2D) TMD remains largely unexplored despite that it plays a critical role reliability functionality TMD-enabled devices. In this work, we study temperature-dependent...
Despite recent progress in the first-principles calculations and measurements of phonon mean-free-paths (MFPs), contribution low-energy phonons to heat conduction silicon is still inconclusive, as exemplified by discrepancies between different calculations. Here we investigate with MFP>0.8 um accurately measuring cross-plane thermal conductivity crystalline films time-domain thermoreflectance (TDTR), over a wide range film thickness 1-10 temperature 100-300 K. We employ dual-frequency TDTR...
While high-throughput (HT) computations have streamlined the discovery of promising new materials, experimental characterization remains challenging and time-consuming. One significant bottleneck is lack an HT thermal technique capable analyzing advanced materials exhibiting varying surface roughness in-plane anisotropy. To tackle these challenges, we introduce spatially resolved lock-in micro-thermography, innovative enhanced by tensor analysis for optical characterization. Our...