National Institute of Standards and Technology
Dr. Joshua Martin is an expert in thermal and electrical transport measurements and instrumentation, focusing on semiconductors and energy materials. His research aims to improve measurement methods, instrumentation, and reference materials for microelectronics and energy conversion applications.
Dr. Martin is well-known for his work in thermoelectric materials used in waste heat recovery and solid-state refrigeration. He has designed and constructed a number of scientific instruments that characterize fundamental properties of bulk and thin film materials with improved measurement speed, accuracy, and reliability. These instruments allowed his team to devise new metrologies, protocols, and models to correct previously unknown or long-ignored sources of errors, resulting in a series of protocol papers describing best measurement practices.
His contributions include developing two Standard Reference Materials for instrument validation, standardizing measurement protocols, and both leading and participating in several international interlaboratory studies on thermal and electrical transport properties. Dr. Martin has received several awards for his work, including the 2021 Department of Commerce Silver Medal Award and the 2014 Department of Commerce Bronze Medal Award.
Dr. Martin’s expertise will provide valuable insights into advancing measurement science for semiconductors and energy conversion technologies at the ITCC.
He will present Development of Thermal Conductivity Reference Materials and host the Thermoreflectance Instrumentation and Methods Workshop.
Abstract:
The thermal properties of materials and interfaces that govern the performance, reliability, and thermal management in semiconductor devices are not fully or easily characterized. Researchers use a variety of techniques to measure thermal properties in this application space and no practical standards currently exist to validate and compare these complex measurements. Thermal reference materials that do exist lack usability due to dimensions or property ranges that are incompatible with current industry tools. Research Grade Test Materials (RGTMs) are a new pre-standards development tool from the National Institute for Standards and Technology (NIST) that provide researchers with no-cost homogenous materials for instrument validation and the reliable interlaboratory comparison of data. We will present our efforts to develop a suite of thermal conductivity RGTMs that span the property value ranges and dimensions relevant for materials used in semiconductor microelectronics and detail how RGTMs fit within the umbrella of standards. We will share the results of a recent online thermal standards survey we conducted to identify and prioritize candidate reference materials, ranges of property values, preferred sample geometry, and prominent measurement techniques. Respondents include contacts from the semiconductor industry, commercial thermal measurement instrument vendors, national and international government laboratories, and academia.
Harvard University
David R. Clarke is the inaugural holder of the Extended Tarr Family Professor of Materials in the Harvard School of Engineering and Applied Sciences. He holds a PhD in Physics from the University of Cambridge, a B.Sc. in Applied Sciences from Sussex University and was awarded a ScD from the University of Cambridge.
A member of the National Academy of Engineering since 1999, he is also a Fellow of both the American Physical Society and the American Ceramic Society, and received an Alexander von Humboldt Foundation Senior Scientist Award in 1993.
He shared the 2008 Japanese NIMS Award for Recent Breakthroughs in Materials Science for Energy and Environment, is a Distinguished Life Member of the American Ceramic Society and was recently listed as author of one of the 11 best papers in the 110 years of publications on ceramics and glasses.
His long-term interests in materials range from the fundamentals to the applied, from ceramics to metals to semiconductors and polymers. He has published over 450 papers in areas of materials ranging from thermal barrier coatings, to dielectric elastomers to fundamentals of oxidation to microelectronics reliability and the electrical and optical properties of ZnO and GaN.
At Harvard, he enjoys interacting with students at all levels, from teaching Freshman seminars on “Glass” and “Materials, Energy and Society”, graduate courses in composites and deformation of materials and the new undergraduate course in SEAS on “Fundamentals of Heat Transfer”, a required course for students studying Mechanical Engineering.
He will present “Thermal Radiation Effects in Materials.”
*The above biography was originally published on https://clarke.seas.harvard.edu/people/david-r-clarke
University of Illinois
David Cahill is the Grainger Distinguished Chair in Engineering, Professor of Materials Science and Engineering, and co-Director of the IBM-Illinois Discovery Accelerator Institute at the University of Illinois at Urbana-Champaign. He joined the faculty of the Department of Materials Science and Engineering at the U. Illinois after earning his Ph.D. in condensed matter physics from Cornell University and working as a postdoctoral research associate at the IBM Watson Research Center.
He served as department head from 2010 to 2018. His research program advances physical insights on thermal transport at the nanoscale; extremes of low and high thermal conductivity; the thermal conductivity of soft matter; the thermal science of magnetic materials; and the transport of heat and mass in battery materials.
Cahill received the 2018 Innovation in Materials Characterization Award of the Materials Research Society, the 2015 Touloukian Award of the American Society of Mechanical Engineers, and the Klemens Award from the International Conference on Phonon Scattering in Condensed Matter; and is a fellow of the MRS, the American Physical Society, the AAAS, and an elected member of the American Academy of Arts and Sciences.
He will present “Beam Deflection Methods and Their Application to Polymers and Fast Mapping of Thermal Conductivity and Interface Conductance.”
More Accurate Analytical Solution for the Modified Transient Plain Source Method
Abstract:
The Modified Transient Plain Source (MTPS) method is a popular one for thermal effusivity and even for other thermal properties tests. The theory used currently for the method assumes that heat capacity of the heater and thermal contact resistances on its surfaces are negligibly small. Obviously, this assumption causes some unknown errors – especially at the early moments of time. To minimize the errors caused by using this imperfect theory the manufacturers of the MTPS devices must run multiple calibrations using several reference materials of known thermal effusivity. Theoretically this kind of method could work as an absolute one with no calibrations at all if a more accurate theory was used – e.g. the Guarded Hot Plate method uses only the measured electric power per square area of the heater, plates’ temperature difference and the sample’s thickness to calculate the absolute value of thermal conductivity. I.e. using accurate theory of the MTPS method we could get absolute values of thermal effusivity.
Now a new, significantly more accurate, analytical solution for the MTPS method is obtained where effects of the heater’s either heat capacity or thermal contact resistance are properly accounted. The heater’s temperatures calculated using the new formulas were numerically compared to its temperatures calculated using the old working formula and were verified using the Finite Differences Method calculations. These new, relatively simple formulas are used to analyze the effect of the heater’s heat capacity or the thermal contact resistance on the various materials tests’ results, what practically was never done before. The heater’s areal heat capacity is calculated using its thickness and volumetric specific heat, or it possibly can be measured directly using its temperature rise rate at the very first moment of time. Thermal contact resistance on the heater’s surfaces is estimated as thickness of the Kapton film divided by the Kapton’s thermal conductivity. These values, as well as the substrate’s thermal effusivity, are used in the new formulas to improve significantly the accuracy and convenience of the MTPS method.
National Institute of Standards and Technology
High throughput nanoimaging of thermal conductivity and interfacial thermal conductance with AFM probes.
Abstract:
Accurate knowledge of thermal conductivity (η) and interfacial thermal conductance (G) at the nanoscale is critical for engineering thermoelectrics, memristors and other advanced electronic devices and for studying thermal transport in nanostructured or quantum materials. However conventional thermal metrology lacks the spatial resolution for measuring thermal properties at the nanoscale.
Photothermal induces resonance (PTIR) [1,2,3] is a scan probe technique that uses the tip on an AFM to transduce the sample photothermal expansion and to enable IR spectroscopy at the nanoscale. However, conventional AFM probes do not have sufficient sensitivity or bandwidth to measure the fast sample thermalization linked to the sample thermal properties.
Here, we develop a low noise (≈ 1 fm/Hz1/2) wide bandwidth (125 MHz) optomechanical cantilever probe and customize a PTIR setup to measure, at once, and with nanoscale resolution, the entire time-domain sample thermal expansion dynamic of the sample due to the absorption of mid-IR laser pulses. Time domain thermalization curves are measured with ≈4 ns temporal resolution, ≈35 nm spatial resolution, and high throughput (≈20 ms per curve) concurrently, enabling nanoimaging of η and G. [4, 5]
As a proof-of-principle demonstration, we obtain 100 × 100-pixel nanoscale maps of η and G in 200 s with a small relative uncertainty (∆η < 10 % and ∆G < 5 %) on a ≈ 3 µm wide polymer particle. Importantly, such measurements do not require extensive probe calibration (as for other AFM-based measurements) or a metallic transducer layer on the sample (often used for TDTR).
This work paves the way to study fast thermal dynamics in materials and devices with nanoscale resolution, which is critical, for example, to study the thermal properties of grain boundaries and of filaments in memristive devices.
Dow Inc.
Errors in non-ideal ASTM D5470 measurements of Type I materials
Abstract:
The ASTM D5470 test method for the determination of thermal resistance and conductivity of thermal interface materials (TIMs) is gaining broader adoption. This method assumes perfectly unidirectional heat flow from a heat source to a heat sink through two reference bars sandwiching a specimen. Perfect alignment and planarity are further assumed. Limited public literature exists to understand the impact of deviations from this ideal scenario.
This work quantifies, through modeling, the systematic errors introduced by several factors, including practical considerations. These sources of error include: (1) imperfect reference bar insulation; (2) imperfect reference bar alignment; (3) imperfections in the reference bars due to wear; (4) specimen overflow; and (5) voids in the specimen. Highest relative errors are generally observed for specimens with high thermal resistance. Experimental results validate the significant impact of specimen overflow, highlighting a need for caution with automated collection of measurements for Type I materials.
Laser Thermal
Thermal investigation of highly mismatched semiconductor alloy PIN diodes
Abstract:
Highly mismatched semiconductor alloys (HMAs) offer greater options for designers of electrical and optical devices by expanding the range of material band gaps and lattice constants from those found in traditional semiconductor alloys. For example, high concentrations of boron (> 20%) have been incorporated into GaAs, decreasing both the lattice constant and the bandgap, creating an enticing III-V platform for photovoltaics, emitters, and detectors. Here we demonstrate PIN photodiodes created from BGa(In)As containing 1-6% boron (2-13% indium) grown by MBE on GaAs substrates. The external quantum efficiency (EQE) is characterized from fabricated circular mesa structures. Steady-state thermoreflectance is used to measure the thermal resistance of the epitaxial film and extract the thermal conductivity.
Dartmouth College
Tailoring thermal properties of Fe2VAl using atomic-site disordering
Abstract:
We report temperature-dependent thermal conductivity to reveal the microscopic phonon scattering mechanisms of Fe2VAl, an emerging and promising thermoelectric material due to its low cost and non-toxicity. As a pseudo-gap semiconductor, Fe2VAl has a good power factor, but its figure of merit is limited by high thermal conductivity. We found that the thermal conductivity can be greatly reduced by Ge doping and atomic site disorder engineering via water quenching from 1120ºC, which is above the order-disorder transition temperature between the fully ordered L21 and partially disordered B2 phase. While the base alloy without doping reports a high thermal conductivity of 28 W/K-m at 300 K, consistent with previous reports in the literature, it is greatly reduced by ~7x to 4W/K-m for Fe2VAl0.9Ge0.1 alloy water-quenched from 1120ºC.
Temperature-dependent thermal conductivity measurement from 4K to 400K reveals that a nearly phonon-glass state is achieved with behavior comparable to that of silica glass, leading to a significant reduction in thermal conductivity because of increased disorder from quenching. The thermal conductivity at a low temperature <100K also shows a linear temperature dependence, suggesting strong electron-phonon scattering. We fit our data to the Debye-Callaway model including boundary scattering, point-defect scattering, phonon-phonon scattering, and electron-phonon scattering terms, which provided new insights into the optimization of thermal conductivity.
Our investigation into the fundamental mechanisms revealed that a strong enhancement in point defect scattering and electron-phonon scattering plays the most significant roles in reducing thermal conductivity, particularly obvious at low temperatures but also extends to at least 400 K. We further examined the effects of different heat treatments i.e slow cooling versus water quenching on the material’s properties, finding that the electron-phonon scattering parameter increases nearly 3x for water-quenched samples, consistent with our computational findings that the water quenching induces metastable L21* phase with a notable increased the effective mass of electrons as well as the experimental measurement of a larger electronic heat capacity. These findings offer valuable strategies for tailoring the thermal properties of Fe2VAl.
The Edward Orton Jr. Ceramic Foundation
Artem is originally from Odintsovo, Moscow region, Russia. He graduated from Russian State University of Aviation Technology in 2012 with B.S./M.S. in physics. The same year he joined Clemson University, where he obtained his M.S. degree in 2014 followed by a Ph.D. in 2018, both in materials science and engineering. His doctoral research primarily focused on ceramic scintillators and their properties.
Following completion of his Ph.D., Artem transitioned to Oak Ridge National Laboratory (ORNL) in 2018 assuming the role of Postdoctoral Fellow. During this tenure, he concentrated on the areas of thermophysics and thermal characterization of materials. After concluding his ORNL fellowship in summer 2021, Artem secured a position at Orton Ceramic Foundation, where he continues his work in the field of thermophysics and materials characterization as a Senior Application Scientist.
He will present “Hot Disk Thermal Conductivity Measurements of Insulation and SRM 1450b”.
Abstract:
With the rising demand for energy-efficient solutions in aerospace, building construction, and semiconductor industries, there is a critical need for novel thermally insulating materials. Traditional thermal characterization methods, while considered accurate, are time-consuming and require large samples, posing challenges for modern material development, where only small samples might be available at the R&D stage. Alternatively, the Hot Disk Transient Plane Source (TPS) technique offers rapid evaluation capabilities even with small specimens.
While the applicability of Hot Disk to thermal insulation has been studied before, previous reports primary focused on comparing thermal conductivity values obtained using Hot Disk measurements with those obtained using other technique(s) from the same lab or among the collaborators. However, to the best of the authors’ knowledge, no literature is available evaluating Hot Disk performance towards actual Standard Reference Material (SRM) with low thermal conductivity. This investigation has a unique opportunity to examine NIST-certified SRM 1450b, among other low thermal conductivity materials.
The presented work shows the application of Hot Disk to measure the thermal properties of various thermally insulating materials, including isotropic and anisotropic samples, with the thermal conductivity ranging from a few hundred mW/m-K (polyethylene, nylon, polyoxymethylene) to a couple dozen mW/m-K (extruded polystyrene, SRM 1450b). Furthermore, using the Anisotropic Module of the Hot Disk technique, the level of anisotropy of SRM 1450b is evaluated and reported for the first time.
Jimma University
Transport properties and microstructural evolution of Bi-Cu-Te ternary alloys
Abstract:
This study delves into the profound influence of defects and their evolution within the microstructure on the thermoelectric transport properties, with a primary focus on the Bi-Cu-Te ternary system. By systematically investigating the intricate relationships between composition, microstructure, and thermoelectric properties, this research offers a comprehensive framework for optimizing these alloys in potential thermoelectric applications. The candidate alloy compositions were selected using a self-consistent thermodynamically optimized database of Bi-Cu-Te and synthesized using flame melting.
The microstructure evolution was characterized using X-ray diffraction (XRD), Scanning Electron Microscope (SEM), and Electron Probe Microanalyzer (EPMA). The presence of γCu3Te2 intermetallic significantly enhanced hardness, with optimized compositions showing a doubling of hardness compared to conventional BiSbTe alloys. The observed morphologies of each alloy and their thermoelectric properties correlate with the Cu concentration variations. An optimized composition exhibited excellent electrical conductivity of 100 kS/m, Seebeck coefficient of -145 μV/K, and power factor of 1.85 mW/mK2. These results provide insights into tailoring the composition and microstructure of Bi-Cu-Te alloys to improve their efficiency for thermoelectric waste heat recovery.
National Laboratory Astana, Nazarbayev University
Phonon heat transport in ion beam modified Ga2O3 thin films.
Abstract:
Ion implantation has been extensively employed to customize the band structure and electrical characteristics of materials for applications in semiconductor technologies. While research on the electronic properties of ion-implanted materials continues to be a field of active research, there is relatively less emphasis on its impact on heat transfer within the material. Ion irradiation introduces defects into the lattice of a material, acting as scattering centers for phonons, which consequently impacts thermal conductivity. However, various factors of the implantation process such as ion mass, energy and temperature create different kinds of defects inside the material when exposed to irradiation. Very recently, we learned that the phase stability of Ga2O3 polymorphs is readily controllable by the accumulation of radiation damage. Thus, using ion beams, different Ga2O3 phases may be stabilized at different spatial locations of ion beam penetration, which can be exploited for thermal energy management.
In this work, we investigate the thermal transport properties of different Ga2O3 polymorphs and particularly the double polymorph γ/β-Ga2O3 structures, fabricated by a self-organized γ-polymorph transformation induced in β-Ga2O3 by ion irradiation. The thermal conductivity was measured by time-domain (TDTR) and frequency-domain thermoreflectance (FDTR), effectively obtaining depth profiles of the thermal conductivity across different Ga2O3 phases. The molecular dynamics simulations with machine-learned potential are also presented to validate the experimental results. Importantly, the formation of such double γ/β-Ga2O3 polymorph structures features an unprecedented sharpness of the γ/β interface leading to abrupt changes in thermal properties across homo-interfaces.
The United States Naval Academy
Time Domain Thermoreflectance: Tips, Tricks, and a few Extensions (workshop)
Abstract:
Time Domain Thermoreflectance (TDTR) is one of the most sought-after techniques for conducting nanoscale thermal measurements. Including electron-phonon coupling, picosecond acoustics, thermal conductivity, and thermal boundary conductance measurements all at once with built in normalization and noise correction is an outstanding prospect. Over the years many researchers have streamlined TDTR systems to attempt to simplify an otherwise complex system. On the flip side, many researchers have extended TDTR to enhance various capabilities and sensitivity (honestly, most of us have done both). In this talk, we’ll discuss a few major options and opportunities with TDTR that can be a great help to TDTR users to help tailor their optical setup, analysis process, and even their design of experiments with samples and controls. In particular, we’ll spend some time discussing Asynchronous Optical Sampling Systems (ASOPS) with TDTR, a technique that effectively removes path-length matching and optical delay stages from TDTR designs (but introduces a new set of tips, tricks, and considerations).
University of Wollongong
Beyond Bulk: Delving into the Vibrational World of Nanodiamonds and Nanocomposite Materials
Abstract:
The significance of understanding thermal transport on the nanoscale continues to increase with the miniaturization of various technology architectures. This principle applies to the design of bulk materials with nanoscale features – in terms of size or periodicity – such as crystal defects, precipitates, or dopants such as nanocrystals. The mechanical vibrations in nanocrystals in the range of GHz-THz are not only important for their role in thermal transport but also for sensing, particularly through their coupling to electromagnetic radiation (optomechanical coupling), which can be utilised for nano-thermometry and more.
In this presentation, I will present our recent work which elucidates the unique lattice dynamics of isolated nanodiamond particles, and the same particles embedded in a thermoelectric matrix. We use a combination of neutron spectroscopy and atomistic simulations to study the evolution of these unique modes which include earthquake-like Rayleigh surface waves (Rayleigh phonons), whole particle breathing modes (Lamb resonances), surface rattling modes, and soft and broad acoustic and optical phonon modes. These modes give rise to a distinctive vibrational density of states compared to bulk diamond. Undoubtedly, these modes play crucial roles in thermal transport, sensing, and catalysis in many nanocrystal systems beyond diamond.
As well as detailing these modes in nanodiamond, we study the impact on the thermal transport of thermoelectric material SnTe by the addition of nanodiamond particles, measured by light flash analysis. We demonstrate a large enhancement factor on the thermoelectric figure of merit originating from the suppression of phonon propagation due to the presence of nanodiamond particles and particle-induced defects. Our work underscores the significance of comprehending size-dependent lattice dynamics for harnessing the full potential of nanodiamonds in diverse technological applications.
University of Virginia
Exploring Plasma-Induced Non-Equilbrium in Thin Gold Films
Abstract:
Plasmas have long been used for the synthesis and manipulation of materials because of their unique ability to deliver both energy and chemically active species to the surface of materials – a feature that separates them from other materials processing techniques. Further, plasma irradiation drives the surface out of thermal equilibrium with the bulk material thus enabling local physicochemical processes that can be harnessed to establish unique material properties. Traditionally, our understanding of energy delivery from plasmas is developed using a variety of temperature measurements, models, and post-irradiation, ex situ surface characterizations to analyze energy deposition and absorption. However, none of these approaches provide a direct measure of the localized, transient response associated with the energy flux at the surface.
In this study, with the use of thermoreflectance based methods, we resolve the influence of the various energetic species in an atmospheric plasma on the resulting transient thermal response of thin gold films. We measure the change in the optical response of these films due to various types, intensities, and temporal profiles of atmospheric pressure plasma excitations. Thus, by using these in-situ thermoreflectance measurements we directly measure the highly non-equilibrium states and the influence of the plasma on the thermal properties of thin film gold during plasma irradiation.
AIT Austrian Institute of Technology GmbH
Thermal conductivity measurements of thermal energy storage materials
Abstract:
Thermal Energy Storage (TES) is an important technology for energy conservation and utilizing fluctuating renewable energy sources and waste heat. Heat transport in TES applications is extremely important as it influences the thermal performance in charging and discharging of the heat storage system.
This work focuses on the use of already available and standardized measurement devices like Laser Flash (LFA), Heat Flow Meter (HFM) and Transient Hot Bridge (THB) to determine the thermal conductivity of phase change (PCM) and thermochemical materials (TCM). Thermal diffusivity a(T) measurements of an organic PCM based on the LFA method indicated a good reproducibility for the solid phase but challenges due to liquid capillary ascension and low viscosity in the liquid phase of the sample. In contrast, thermal conductivity experiments via the THB method have shown their assets in the liquid phase but on the other hand unsatisfactory results in the solid phase due to varying contact conditions between foil sensor and sample. A numerical investigation of a LFA liquid sample holder system filled with pure water has shown the transient and spatial temperature field distribution inside the sample holder system and the influence on the measured half time depending on the detector focus.
Furthermore, measurement protocols to analyze the effective thermal diffusivity aeff (T) and effective thermal conductivity λeff(T) of powdery TCM candidates were developed. The results represent the strong dependency on the actual bulk density of the measured sample. Finally, a detailed investigation on of packed beds consisting of a Yttria-stabilized zirconia powder with different particle diameters based on the LFA, THB and HFM method were performed and compared. The LFA results indicate a significant relation between the aeff (T) and the used gas conditions. Under ambient conditions, the HFM and THB method indicate comparable λeff (T) data while LFA showed significant higher values. Considerations about a non-uniform distribution of the powder inside the LFA sample holder system led to the assumption, that the evaluated bulk densities are not correct and also plane-parallelism is not given, which is a requirement for accurate LFA measurements.
Harvard University
David R. Clarke is the inaugural holder of the Extended Tarr Family Professor of Materials in the Harvard School of Engineering and Applied Sciences. He holds a PhD in Physics from the University of Cambridge, a B.Sc. in Applied Sciences from Sussex University and was awarded a ScD from the University of Cambridge.
A member of the National Academy of Engineering since 1999, he is also a Fellow of both the American Physical Society and the American Ceramic Society, and received an Alexander von Humboldt Foundation Senior Scientist Award in 1993.
He shared the 2008 Japanese NIMS Award for Recent Breakthroughs in Materials Science for Energy and Environment, is a Distinguished Life Member of the American Ceramic Society and was recently listed as author of one of the 11 best papers in the 110 years of publications on ceramics and glasses.
His long-term interests in materials range from the fundamentals to the applied, from ceramics to metals to semiconductors and polymers. He has published over 450 papers in areas of materials ranging from thermal barrier coatings, to dielectric elastomers to fundamentals of oxidation to microelectronics reliability and the electrical and optical properties of ZnO and GaN.
At Harvard, he enjoys interacting with students at all levels, from teaching Freshman seminars on “Glass” and “Materials, Energy and Society”, graduate courses in composites and deformation of materials and the new undergraduate course in SEAS on “Fundamentals of Heat Transfer”, a required course for students studying Mechanical Engineering.
He will present “Thermal Radiation Effects in Materials.”
*The above biography was originally published on https://clarke.seas.harvard.edu/people/david-r-clarke
University of Illinois
David Cahill is the Grainger Distinguished Chair in Engineering, Professor of Materials Science and Engineering, and co-Director of the IBM-Illinois Discovery Accelerator Institute at the University of Illinois at Urbana-Champaign. He joined the faculty of the Department of Materials Science and Engineering at the U. Illinois after earning his Ph.D. in condensed matter physics from Cornell University and working as a postdoctoral research associate at the IBM Watson Research Center.
He served as department head from 2010 to 2018. His research program advances physical insights on thermal transport at the nanoscale; extremes of low and high thermal conductivity; the thermal conductivity of soft matter; the thermal science of magnetic materials; and the transport of heat and mass in battery materials.
Cahill received the 2018 Innovation in Materials Characterization Award of the Materials Research Society, the 2015 Touloukian Award of the American Society of Mechanical Engineers, and the Klemens Award from the International Conference on Phonon Scattering in Condensed Matter; and is a fellow of the MRS, the American Physical Society, the AAAS, and an elected member of the American Academy of Arts and Sciences.
He will present “Beam Deflection Methods and Their Application to Polymers and Fast Mapping of Thermal Conductivity and Interface Conductance.”
Thermtest
David is the Thermophysics Research Manager at Thermtest Inc. Over his five years with Thermtest, he has worked with every transient and steady-state measurement technique offered. He spends his time making improvements to the measurement platform, from better data analysis tools and upgraded calculation algorithms to the integration of whole new methods using transient sensors.
He will present “Measurement of Layered Samples Using the Transient Plane Source” and host a workshop on “Thermoreflectance Methods”.
National Institute of Standards and Technology
Frequency Domain Thermoreflectance (FDTR) Instrumentation: Common Challenges and Practical Guidance
Abstract:
Frequency Domain Thermoreflectance (FDTR) is a pump-probe technique capable of non-contact thermal property measurements on thin films and multilayer structures. FDTR instruments can be challenging to setup since they are traditionally home built and there are minimal details and guidance reported in the literature. Ultimately, without prior experience or the assistance of an expert, FDTR instruments are difficult to construct, align, and maintain. In this talk, we will provide our insights and institutional knowledge that are critical for obtaining accurate and repeatable measurements of thermal properties using FDTR. We discuss component selection and placement, alignment procedures, data collection parameters, and commonly encountered challenges. In FDTR, the unknown thermal properties are fit by minimizing the error between the phase lag at each frequency and the multilayer diffusive thermal model solution. For data fitting and uncertainty analysis, we compare common numerical integration methods, and multiple approaches for fitting and uncertainty analysis, including Monte Carlo simulation, to demonstrate their reliability and relative speed.
Österreichisches Gießerei-Institut
Thermal diffusivity and conductivity of a flexible thermal protection system (FTPS)
Abstract:
A flexible thermal protection system (FTPS) is needed to enable the use of deployable and inflatable hypersonic decelerators on aerocapture, entry, descent, and landing missions. An ESA technology development study was completed to define an FTPS that may be integrated with a Mars-entry inflatable hypersonic decelerator. The FTPS consists of three functional layers: (i) a protective outer layer, resistant to high heat flux; (ii) an insulation layer to delay the entry heat pulse; and (iii) a gas barrier layer to prevent hot gases/decomposition products from damaging the underlying structure. The individual materials must comply with a series of requirements, e.g., thermophysical and – mechanical properties, flexibility, handling, and manufacturability. Insulation materials with hightemperature performance, flexibility and low thermal conductivity were selected and characterized.
This work reports measurements of thermal diffusivity and conductivity of selected individual layer materials as well as heat transfer through layered stacks. The basic measurements were performed with classical laboratory means e.g., laser-flash, DSC, or thermogravimetry. The fabric and felt structure, as well as the low thermal conductivity of these materials posed some measurement challenges.
Additionally, thermal conductance tests on 120 mm x 120 mm stacks, instrumented with thermocouples between the individual layers, were performed by applying a graphite crucible containing solidifying copper at one surface. The obtained thermophysical data was incorporated in a numerical model to describe the temperature development in the FTPS during atmospheric entry, which in turn was tested by plasma arc-jet testing.
University of Virginia
Considerations in the measurement of high thermal conductivity materials with steady-state thermoreflectance
Abstract:
In this presentation, we consider the challenges in the measurement of high thermal conductivity materials with themoreflectance techniques. We focus upon the steady-state thermoreflectance (SSTR) method and and compare with other common opto- and electrothermal techniques. An analysis is performed on polycrystalline CVD diamond substrates with thermal conductivity in excess of 2000 W m-1 K-1. Variants of the SSTR technique including lock-in amplification (LIA) and periodic waveform analysis (PWA) are compared.
C-Therm Technologies
Measuring the In-plane Thermal Conductivity of Pyrolytic Graphite Sheets using the Transient Plane Source Method.
Abstract:
Pyrolytic graphite sheets are synthesized thermal interface material with high in-plane thermal conductivity and a thin film structure offering a lightweight, flexible, and customizable solution in thermal management applications. The typical manufacturing process involves pyrolysis of hydrocarbon precursors at very high temperatures while applying tensile stress in the basal-plane direction, improving the graphitic crystals’ alignment and interlayer contact. Variability in the manufacturing process, such as temperature and annealing pressure, can have a major impact on the foil’s thermal and physical properties. The pyrolytic graphite sheets’ high thermal conductivity, high crystallinity, and low phonon scattering have been previously correlated in various published works and literature. Traditionally, the thermal conductivities of highly oriented pyrolytic graphite sheets are estimated and derived through models or measured through flash methods, which can be prone to drawbacks such as heat loss error and finite pulse-time effects.
In this work, we measured the in-plane thermal conductivity of the pyrolytic graphite sheets using the FLEX Transient Plane Source (TPS) method available on C-Therm’s Trident platform. The pyrolytic graphite sheets were sourced from HPMS Graphite, with varying reported densities (1.5-2.3 g/cm3) and thin film thicknesses (12-100 µm). Overall, a correlating trend between higher thermal conductivity and thinner and denser pyrolytic graphite sheets was observed.
Linseis Inc.
Instrumentation for Thin Film Thermal Conductivity Measurements
Abstract:
Measuring the thermal conductivity of thin films presents several challenges due to their small size, the need for high accuracy, and the importance of ease of use. Addressing these challenges often involves meticulous sample preparation, advanced measurement techniques, and careful experimental design.
In this talk, we will introduce the instrumentation of the TFA (Thin Film Analyzer), based on the 3-omega method for in-plane thermal conductivity measurement, and the TF-LFA-FDTR (Thin Film-Laser-Frequency Domain Thermoreflectance) for cross-plane measurement.
For the TFA, to reduce the large uncertainties caused by sample preparation, prefabricated chips are provided for thin film deposition. The hot-stripe heater and temperature measurement connections are all prebuilt on the chip, making sample preparation straightforward.
In the TF-LFA-FDTR, besides the advantage of direct thermal conductivity measurement, there is little need to adjust the probe laser beam. The easy sample setup and more stable measurement process enhance overall reliability and efficiency.
At the end, we will present detailed application measurements using both instruments.
Oak Ridge National Laboratory
Dr. Hsin Wang is a distinguished scientist with expertise in the thermal transport properties of materials, energy conversion materials, and energy storage materials. He has also conducted extensive research on thermal and electronic transport study of irradiated materials.
Dr. Wang has been a subject matter expert (SMB) at NASA/DOE radioisotope power system (RPS) program NextGen program and member of the review board of eMMRTG. He has served as the Annex VIII leader on thermoelectric and thermal management materials at the International Energy Agency (IEA) advanced materials for transportation (AMT) since 2010. He was the chairman of ITCC board of directors from 2007-2011, ITCC Fellow and a current BOD member. He hosted ITCC23/ITES15 in Knoxville, TN in 2003 and International Thermoelectric Conference (ICT) in Nashville in 2014. He was the board member of the International Thermoelectric Society (ITS) from 2012-2019.
He will present “Thermal Conductivity of Materials in the Radioisotope Thermoelectric Generators (RTGs)”
Oak Ridge National Laboratory
Very Low Thermal Conductivity in Thermoelectric Pseudo-Hollandite Chalcogenides
Abstract:
Transition metal chalcogenides have drawn much interest in past decades for thermoelectric applications. This is the case for instance of pseudo-hollandite chalcogenides of typical formulae AxM5X8 (A = Rb, Ba, Tl, K, Sr, In, CsM = Ti, V, CrX = S, Se, Te). These compounds exhibit an anionic framework made of the assemblage of face- and edge-sharing M-centered MSe6 octahedra forming infinite channels along the c-axis. The resulting one-dimensional channels can be fully or partially filled with cations which stabilize the structure and act as rattlers for phonons. The complexity and chemical flexibility of such a structure are of interest, especially in thermoelectric applications where very low thermal conductivities are needed. Several examples of low thermal conductivity pseudo-hollandites will be presented, establishing a comprehensive relationship between their structure and their thermal properties. A new quaternary pseudo-hollandite has recently been synthesized and characterized, and its properties will be compared to other related materials which exhibit extremely low thermal conductivities, typically below 1 W·m-1·K-1.
University of Virginia
Novel contactless measurement technique to determine the thermal conductivity and spectral emissivity of materials at ultra-high temperatures (>2000 °C)
Abstract:
New ultra-high temperature ceramics (UHTCs) are being developed as candidate hot structures for use as thermal protection systems with space and hypersonic vehicle applications. UHTCs experience extreme heat fluxes during hypersonic flight, resulting in peak surface temperatures well above 2500 °C. New hypersonic vehicles aim to operate at lower altitudes with smaller leading-edge radii, resulting in even greater heating and thus higher surface temperatures. Currently there is limited understanding of the thermal and radiative properties at relevant temperatures (>2000 °C) due to the difficulties conducting thermophysical properties measurements at these extreme temperatures.
In this work we present a newly developed contactless measurement technique based on modulated laser heating, thermal imaging and hyperspectral radiative pyrometry to measure the thermal conductivity and spectral emissivity of UHTC materials from room temperature up to and through their melting points. This technique utilizes laser heating and hyperspectral radiative pyrometry to measure the temperature response at the sample surface subject to small perturbations in laser flux. We use a finite solution to the 2D steady-state axisymmetric heat equation with radiative boundary conditions to fit our experimental data. We validate this technique on standard metals tungsten and molybdenum by measuring their thermal and radiative properties from 2000 °C through their melting points as shown in Fig. 1. We then further evaluate our technique by measuring the thermal conductivities of TaC, HfC, ZrC and TiC from room temperature to 2000 °C, and compare our values with literature.
Lastly, we measure the thermal conductivity and spectral emissivity of these materials as well as a novel high-entropy carbide (HEC) above 2000 °C for the first time. Thermal conductivity and spectral emissivity measurements at relevant temperatures are crucial for evaluating and influencing the design of the next generation of extreme temperature thermal protection systems.
PMIC
Method for determination of thermal conductivity of open and closed cell materials at cryogenic temperatures
Abstract:
Measurement of the thermal conductivity of open and closed cell materials in a non-vacuum environment at cryogenic temperatures requires the application of a suitable cryogen. In the temperature range below the boiling point of liquid nitrogen, usage of the noble gas helium having the lowest boiling point among all elements, represents a challenge. Because helium has a small molar mass of approximately 4 g/mol in comparison to approximately 28 g/mol for nitrogen gas, gaseous helium effuses almost 3 times faster through microscopic pores according to Graham’s law. Furthermore, gaseous helium has a significantly higher thermal conductivity at atmospheric pressure than nitrogen by an average factor of 7. This appears to result in a higher apparent thermal conductivity of the open and closed cell material.
The ASTM Standard Test Method for steady-state heat flux measurements and thermal transmission properties by means of the guarded-hot-plate apparatus was used to measure the thermal conductivity of thermally insulating cellular glass at cryogenic temperatures. Measurements were performed in helium as well as nitrogen atmospheres in the upper temperature range allowing an offset value, caused by the increased heat flow through helium, to be determined. The offset value was used to correct the thermal conductivity values obtained at lower temperatures in helium atmosphere.
National Institute of Standards and Technology
Investigations for experimental parameters of thermal conductivity measurements of expanded polystyrene boards using a heat flow meter and transient plane source apparatuses
Abstract:
The need for requiring building envelopes with high performance is continuously increasing with demands of energy efficiency and energy conservation in residential building applications. The thermal performance of a building envelope depends on thermal properties of its constituent materials including specific heat capacity and thermal conductivity. Among commercial instruments, both heat flow meter (HFM) and transient plane source (TPS) instruments can provide these thermal data using a relatively bulky specimen compared to differential scanning calorimeter (DSC).
Since two instruments measure thermal properties in different thermal states, assessing parameters that influence on the measured data is important in comparing the results. Furthermore, compared to HFM, TPS can be deployed in field environments as well as lab environments due to its sensor size. Considering a more complicated building envelope with thermal storage capability (e.g., phase change material) and multi-layers, understanding the role of the individual layers will be improved by correlating the relation between two instruments.
In this study, we ran 24 full factorial experiments to measure thermal conductivities of expanded polystyrene (EPS) boards with different densities, surface roughnesses, and temperatures using HFM and TPS instruments. The thermal conductivity data of EPS boards are statistically analyzed to obtain a ranked list of the importance of the factors and estimates of the effect sizes of each factors on the thermal conductivity measurements. The summary of the results is presented in the conference.
Laser Thermal
Thermo-Optical Plane Source technique for Thermal Conductivity Measurement
Abstract:
We demonstrate a Thermo-Optical Plane Source (TOPS) technique to measure the thermal conductivity of materials. This high-throughput, simple, and efficient method measures thermal conductivity of materials with minimal sample preparation and limited restrictions on sample shape and geometry. Moreover, the technique is applied to solids, liquids, gels, and pastes with no change in implementation. The TOPS technique uses laser heating to induce a steady-state temperature rise in a material and infrared thermography to measure the corresponding temperature rise. Fourier’s law is applied to directly measure thermal conductivity, rather than thermal diffusivity or effusivity, negating any need to know density or heat capacity. We demonstrate the ability to measure thermal conductivities ranging from 0.05 W/m-K to 60 W/m-K at room temperature.
University of Virginia
Non-Contact Method for Measuring Thermal Conductivity and Melting Point: A Comparative Study of Thermal Properties in SS316L Samples Fabricated via Additive Manufacturing and Machining
Abstract:
Additive manufacturing (AM) has become increasingly popular in recent years due to its capability to produce complex geometries while reducing the product’s weight. However, in contrast to traditional manufacturing processes, it also introduces uncertainty in the thermal properties, requiring further verification steps. Thus, a thorough assessment of the properties of the manufactured parts is essential to ensure they meet the necessary standards for their intended applications.
In this context, traditional contact-based methods are often adopted to measure thermal conductivity. However, they present several challenges, such as sample preparation, limited temperature ranges, the need for additional coatings, and difficulties in measuring anisotropic materials. To overcome these challenges, in this study, we use a non-contact method to measure the thermal properties of SS316L fabricated via AM and compare the results with those of parts produced through traditional machining techniques. Non-contact methods for measuring thermal properties, overcome the limitations of traditional counterparts, offering more reliable and precise measurements.
The non-contact technique employed in this study uses a continuous wave (cw) green laser to heat the sample, while an infrared camera monitors the temperature rise. The observed temperature changes are analyzed using a one-dimensional steady-state mathematical model, enabling the calculation of spatial thermal conductivity. This approach is particularly beneficial for evaluating anisotropic materials and is directly applicable in determining whether the AM process induces anisotropic structures during post-processing, in comparison to traditionally machined materials. Figure 1 illustrates the relationship between thermal conductivity, temperature gradient, and radial coordinates. Our findings show that at output power of 0.50 W, the thermal conductivity of additive-manufactured stainless steel(green dotted line) closely matches that of bulk machined material (blue square line), highlighting the reliability of the non-contact technique.
Laser Thermal
John Gaskins is co-founder and CEO of Laser Thermal. After nearly two decades of research at the University of Virginia in nanoscale property measurements, John now leads Laser Thermal in its pursuit to bring accessible and high-throughput thermal metrology tools to industry. In addition to leading Laser Thermal, he serves on the board of trustees for GENEDGE, Virginia’s member of the NIST MEP network, which serves manufacturers across the Commonwealth. He lives in Charlottesville with his wife and two children.
*This biography was originally published on https://laserthermal.com/leadership-team/
National Institute of Standards and Technology
Dr. Joshua Martin is an expert in thermal and electrical transport measurements and instrumentation, focusing on semiconductors and energy materials. His research aims to improve measurement methods, instrumentation, and reference materials for microelectronics and energy conversion applications.
Dr. Martin is well-known for his work in thermoelectric materials used in waste heat recovery and solid-state refrigeration. He has designed and constructed a number of scientific instruments that characterize fundamental properties of bulk and thin film materials with improved measurement speed, accuracy, and reliability. These instruments allowed his team to devise new metrologies, protocols, and models to correct previously unknown or long-ignored sources of errors, resulting in a series of protocol papers describing best measurement practices.
His contributions include developing two Standard Reference Materials for instrument validation, standardizing measurement protocols, and both leading and participating in several international interlaboratory studies on thermal and electrical transport properties. Dr. Martin has received several awards for his work, including the 2021 Department of Commerce Silver Medal Award and the 2014 Department of Commerce Bronze Medal Award.
Dr. Martin’s expertise will provide valuable insights into advancing measurement science for semiconductors and energy conversion technologies at the ITCC.
He will present Development of Thermal Conductivity Reference Materials and host the Thermoreflectance Instrumentation and Methods Workshop.
Abstract:
The thermal properties of materials and interfaces that govern the performance, reliability, and thermal management in semiconductor devices are not fully or easily characterized. Researchers use a variety of techniques to measure thermal properties in this application space and no practical standards currently exist to validate and compare these complex measurements. Thermal reference materials that do exist lack usability due to dimensions or property ranges that are incompatible with current industry tools. Research Grade Test Materials (RGTMs) are a new pre-standards development tool from the National Institute for Standards and Technology (NIST) that provide researchers with no-cost homogenous materials for instrument validation and the reliable interlaboratory comparison of data. We will present our efforts to develop a suite of thermal conductivity RGTMs that span the property value ranges and dimensions relevant for materials used in semiconductor microelectronics and detail how RGTMs fit within the umbrella of standards. We will share the results of a recent online thermal standards survey we conducted to identify and prioritize candidate reference materials, ranges of property values, preferred sample geometry, and prominent measurement techniques. Respondents include contacts from the semiconductor industry, commercial thermal measurement instrument vendors, national and international government laboratories, and academia.
Oak Ridge National Laboratory
Dr. Lucas Lindsay received a BS degree in physics from the College of Charleston in 2004. He did his PhD work on theoretical thermal transport in carbon nanostructures at Boston College and received his PhD in 2010. Following this he taught physics for two years at Christopher Newport University, then spent three years as a National Research Council Postdoctoral Fellow at the U.S. Naval Research Laboratory in Washington, D.C. He has been a research scientist in the Materials Science and Technology Division at Oak Ridge National Laboratory since 2014. He received the Department of Energy Early Career Award in 2019. His general research area is the theoretical description of vibrational and transport properties of condensed matter.
He will present Unveiling the Theory of Thermal Conductivity: Insights into Phonons and Heat Transfer Mechanisms.
Gdańsk University of Technology
Study of heat conduction in human skin irradiated with a dedicated laser for heating gold nanoparticles for cancer photothermoablation
Abstract:
The primary purpose of this study is to evaluate the process of heat conduction in skin subjected to photothermoablation in a customized chamber measured with a thermal imaging camera. Investigation of the effect of gold nanoparticles on the skin surface and their laser irradiation on the conditions of heat flow into the skin will be preliminarily determined by determining temperature-time curves. Both an experimental rig and Computational Fluid Dynamics (CFD) numerical calculations are used to verify the results. CFD uses mass, momentum and energy balances; however, in the present issue, the determination of the temperature field in the solid remains crucial in the first estimation of the results.
Tissue samples (medical waste after procedures) after gold application are transferred to the laser laboratory for irradiation with an electromagnetic energy source of about 1 W. During the study, spherical gold nanoparticles will be used, which, using different laser wavelengths – from visible light to short-wave infrared region (SWIR), will serve as a source for converting electromagnetic energy into heat.
Analyses of heat transfer over time are conducted using thermal imaging cameras with recording of the temperature change on the heated surface. Selected results of the measurement campaign will also be analysed using CFD-type tools to indicate the possibility of determining the depth and size of the heated area. The experimental and numerical results will be confronted with the literature on an ongoing basis. The present research results will be used in the future to determine the power, wavelength, heating time in terms of optimizing the process of photothermoablation of tumors.
University of Virginia
Characterizing the Anisotropic Thermal Properties in Irradiated 2D hexagonal-Boron Nitride (h-BN) Flakes
Abstract:
2D-materials, such as hexagonal boron nitride (h-BN), are promising candidates for deployment in radiative environments, such as space instrumentation (e.g., spacecraft shielding, studying solar flares), nuclear reactors, long-distance quantum communication, etc. The ability for precise transport measurements and a subsequent investigation into the resulting structural damage mechanisms as a function of ion irradiation is, thus, of critical importance. In this talk, we focus on using time domain thermo-reflectance (TDTR), in both its concentric and beam offset configurations, to resolve the in-plane and cross-plane thermal conductivities of h-BN flakes, as a function of radiation exposure. We experimentally demonstrate a significant reduction in the in-plane thermal conductivity of h-BN (by up to an order of magnitude) upon increased ion dosage, whereas the cross-plane thermal conductivity is reduced by only up to a factor of 2. This dramatically different orientational thermal property response to irradiation in h-BN, as opposed to other conventional bulk materials such as silicon, presents an interesting opportunity to explore various unique forms of radiation-induced damage such as ballistic displacements caused by quasi-elastic scattering (knock-on damage), radiolysis, and other de-ionizing effects in 2D materials.
University of Virginia
Ballistic Thermal Transport in TiN/TiC Multilayers due to Interfacial Elastic Modulus Enhancement
Abstract:
The scale of microelectronics is gradually reducing towards dimensions comparable with the electron mean free path. Since there is a need to dissipate ever increasing amounts of waste heat in microelectronic applications the increased device and interface density is highly undesirable. Thus, the approach of engineering materials with high densities of interfaces to achieve desirable thermal conductivity solids requires a fundamental understanding.
In this work, we report on the thermal conductivity of a series of crystalline multilayers composed of alternating layers of titanium nitride and titanium carbide with varying interface densities. We deposit titanium nitride and titanium carbide superlattice films on MgO(001) by reactive magnetron sputtering in an ultra-high vacuum chamber. The alternating nitride carbide layers are formed using reactive mixtures of Ar/N and Ar/CH4, respectively. The 1 um thick samples are deposited at 1100 °C with alternating layer thicknesses between 1.5 and 15 nm. We directly measure the thermal conductivity of these films via the time-domain thermoreflectance technique. We find that the thermal conductivity increases with an increasing interface density indicating that the heat carriers are scattering less in the interfaces of the multilayers.
This finding contradicts the traditional theory and conventional understanding. The role of interfacial nonidealities and disorder on thermal transport across interfaces is traditionally assumed to add resistance to heat transfer. The increase in thermal conductivity could be related to their increase in their elastic modulus which was measured by picosecond acoustic and nanoindentation techniques. The increase in interface density leads to a monotonically increasing elastic moduli imply a high quality of interface formation which usually results in a higher thermal conductivity. Our results demonstrate a path toward engineering thermal conductivity, thus providing a novel approach to dissipate the ever-increasing amounts of waste heat in microelectronic devices and alleviate the concern for the continuation of Moore’s law.
University of Virginia
Thermal Conductivity, Melting Temperature and High-Temperature Emissivity of Rare-Earth Silicate Environmental Barrier Coatings
Abstract:
In recent years, rare-earth silicates have become the industry standard for coating state-of-the-art silicon carbide ceramic matrix composites for gas turbine engine components, due to their low volatility, high melting point, and thermal shock resistance. Current research looks to design rare-earth silicate based thermal and environmental barrier coatings (T/EBCs) with improved resistance to steam, CMAS (CaO-MgO-Al2O3-SiO2), and thermal stresses, while maintaining high temperature performance and stability. In this work we study the room temperature thermal conductivity and high temperature limits of a variety of single and multiple principle component rare-earth mono- and disilicates and rare earth apatites.
To study thermal transport in the rare-earth silicates, we measure thermal conductivity by time-domain thermoreflectance (TDTR). For high temperature measurements, a laser heating and radiation pyrometry based technique is employed to measure the melting point and high temperature emissivity of these materials systems. In this approach, a high-power IR laser is used to heat the sample just beyond its melting point while both a 256-channel spectropyrometer and a single-wavelength pyrometer with high temporal resolution monitor the radiative temperature of the sample surface in the center of the heated region. While the sample surface is locally molten, the laser is shuttered and the melting point is captured through the observed thermal arrest in the temperature response during cooling.
To ascertain the real melting temperature from the measured radiative temperature, we utilize the spectrally resolved pyrometer response to calculate the gray emissivity in the visible, and apply this to the fast, single-wavelength pyrometer measurement. We find our results agree with trends observed in previous literature. The thermal conductivity, melting point and emissivity measurements are used to evaluate each material’s feasibility as a thermal and environmental barrier coating in a high temperature gas turbine environment.
University of Virginia
Characterization of Thermal and Mechanical Properties of Plasma-Based Aluminum Fluoride Layers
Abstract:
Aluminum is highly valued in UV optics for its ability to reflect wavelengths as short as 90 nm effectively. However, its effectiveness as a reflector is compromised by a rapidly forming native oxide layer. To mitigate this issue, fluorine-containing layers, which inhibit oxidation and maintain high transmission rates, have been applied. Additionally, aluminum fluoride layers serve as effective barrier coatings in advanced Li-ion battery designs, preventing common failures such as significant temperature increases and thermal runaway. Despite these applications, the thermal and mechanical properties of aluminum fluoride thin films have not been thoroughly reported. To explore these properties, we employed plasma-generated aluminum fluoride passivation layers of varying thicknesses. Our measurements reveal that both the elastic modulus and thermal conductivity of the fluorinated layers increase with thickness. This variation suggests a thickness-dependent chemical composition, as evidenced by EDS/EDX spectra showing that thinner layers contain a higher proportion of aluminum and less fluorine compared to thicker layers, thus explaining the observed variations in modulus.
SRM Institute of Science and Technology
Realizing the low thermal conductivity of SnS by utilizing the phonon liquid-like behavior of Cu2Se
Abstract:
SnS is a highly promising multilayer chalcogenide material that shows great potential for thermoelectric applications. We use a simple hydrothermal route to synthesize SnS/Cu2Se (1%, 3%, 5%, and 7%) composites. SnS has a high Seebeck coefficient but lacks good electrical properties, so the introduction of Cu2Se to the SnS matrix can be a potential solution for the overall improvement of the composite. The addition of Cu2Se has resulted in the suppression of intrinsic thermal conductivity of SnS from 0.891 W/mK to 0.447 W/mK for SnS/Cu2Se 5% at 753 K. The specific heat capacity, as well as diffusivity, show a monotonic trend with respect to temperature. Increasing the Cu2Se% in the matrix has led to a decrease in the crystallite size.
While the dislocation density and microstrain showed an increasing trend. We have analyzed different physical and microstructural factors influencing thermal conductivity using numerical techniques. Physical factors like the distribution of Cu2Se, temperature, and pressure used for pelletizing, volume fraction, and inherent material properties are analyzed using an effective thermal conductivity approach, and the interfacial thermal conductivity is analyzed by the Hasselman-Johnson model. We also analyze microstructural factors, like dislocations, stacking faults, and point defects. The phonon relaxation time of each mode of vibration is also calculated by utilizing Raman spectroscopy. All these factors play crucial roles in the reduction of almost 50% in the thermal conductivity of the SnS/Cu2Se samples.
Arrigo Enterprises, LLC
The Use of Light Emitting Diodes (LED) in Thermal Diffusivity Testing by the Flash Method
Abstract:
Ever since the first introduction of the flash method, a variety of flash sources have been utilized to provide the needed energy pulse. Recently, LED sources have been used with success. A comparison of the LED pulse source with previously used pulse sources is discussed. Advantages and limitations, with special emphasis on the effect of lower energy and longer duration pulses are presented, along with construction principles employed in producing a viable application.
Gdańsk University of Technology
Theoretical investigations of the photothermal effect and energy conversion for metallic nanostructures deposited on insulated materials
Abstract:
Photothermal effect in metallic nanostructures has been extensively studied for a dozen years due their high biocompatibility and the effective energy conversion rate. Moreover, the immediate temperature increase, which occurs as a result of the illumination, could be applied in the biophysical systems where germs or tumors are to be completely inactivated or overheated. However, there is a low number lack of theoretical methods that could predict the temperature increase and the energy conversion rate, and yet assist in water purification station or clinical trials. This work aims to compare experiments with three different theoretical models, which have been developed and adjusted by authors.
The first theory includes the Rayleigh-Drude approximation within size and shape effects described by optical cross-sections, whereas the second model assumes the efficiency of the energy conversion measured by a laser-power meter. On the other hand, the third approach considers the combined analytical solutions for unsteady heat transfer and the nanofluidic equations determining the effective thermal diffusivity. All models are tested and examined using the platforms where cetyltrimethylammonium bromide (CTAB)-stabilized gold nanorods have been uniformly deposited on a thin 0.4-inch round sheet made of optical borosilicate glass. The platforms are subsequently subjected to 0.5-W visible- and infrared-range laser illumination. The obtained results indicate that the maximum temperature from experiments reaches 𝑇𝑚𝑎𝑥=121.0C o (249.8F o) in approximately ten seconds and remains constant for the rest of the illumination time. As long as each model provides a satisfactory trend over time, the first and the second theories exhibit the best agreement with experimental values (𝑇1=118.9C o (246.0F o) and 𝑇2=120.1C o (248.2F o)), and outperform the third model as respectively overestimated at the 25% level.
Technical University Berlin
Temperature-Dependent Thermal Conductivity of Rutile Germanium Dioxide (GeO2) Measured by Time-Domain Thermoreflectance
Abstract:
The demand for power electronics devices is experiencing rapid growth across various sectors, driven by their enhanced functionality, energy efficiency, and system reliability. A crucial factor in meeting these demands is the advancement of ultra-wide bandgap emiconductors. In this context, rutile germanium dioxide (r-GeO2) is gaining attention as a promising semiconductor material with an ultra-wide bandgap of 4.68 eV [1] comparable to materials of significant interest like β-Ga2O3. However, unlike β-Ga2O3, r-GeO2 may provide both n- and p-type conductivity. Additionally, r-GeO2 has a higher and less anisotropic thermal conductivity compared to β-Ga2O3, making it an attractive semiconductor for power electronic devices where heat management is crucial. So far, experimental studies have only reported the thermal conductivity of r-GeO2 at room and elevated temperatures [2].
For the first time to our knowledge, we performed temperature-dependent measurements of the thermal conductivity of r-GeO2 in the [001] and [110] directions in the temperature range between 80 to 300 K. For the measurements, we used samples prepared from bulk r-GeO2 single crystals grown by the Top-Seeded Solution Growth method at Leibniz-Institut für Kristallzüchtung, as described in detail elsewhere [3]. The thermal conductivity was measured utilizing our in-house developed two-color time-domain thermoreflectance setup. Our findings closely align with the theoretical results previously published by Chae et al. [2], showing higher thermal conductivity in the [001] direction as compared to the [110] direction.
This work was funded by the Leibniz-Gemeinschaft (Senatsausschuss Wettbewerb – SAW, Germany) project under grant number K417/2021. It was partly performed in the framework of GraFOx, a Leibniz-Science Campus partially funded by the German Leibniz Association.
Harvard Unviersity
Thermal Transport in Materials with Dynamic Conformational Disorder
Abstract:
Alkyl chains that undergo phase transitions between ordered and dynamically disordered states have been the centerpoint of numerous thermal energy applications, notably solid-state cooling through barocaloric effects. Understanding how heat flows along these chains can offer valuable insights for device engineering and efficiency. In this talk, I will discuss thermal transport in layered crystals whose alkyl chains undergo sharp order–disorder transitions, including hybrid perovskites and organic salts. As these materials offer tunable interchain chemistries, we measure the thermal conductivities of systematically varied structures through frequency-domain thermoreflectance (FDTR) to assess the role of non-covalent interactions and chain confinement. Quasielastic and inelastic neutron scattering measurements further enable us to understand how conformational disorder influences the type of thermal carriers and the amount of heat they carry. Our results demonstrate a molecular-level picture of thermal transport in these materials and suggest the critical structural features that dictate heat conduction.
University of Virginia
In-plane Thermal Conductivity Measurements in Reticular Organic Films: Challenges and Perspectives
Abstract:
he advent of reticular chemistry has made it possible to engineer highly crystalline open organic structures such as metal organic frameworks (MOFs) and covalent organic frameworks (COFs), with tunable anisotropic transport properties. Molecular dynamics (MD) simulations predict an anisotropy ratio of up to ~4 in the in-plane versus cross-plane thermal conductivities in some of these materials. However, an experimental in-plane thermal conductivity measurement of these delicate porous structures is challenging, especially when using existing pump-probe metrologies such as TDTR, FDTR and SSTR. This is largely due to the necessity of depositing an optically opaque transducer (usually ~80 nm of Al) which diminishes sensitivity to the thermal properties of the underlying COF/MOF layer, on account of the dominant in-plane thermal currents in the transducer.
To overcome this challenge, in my talk, I discuss the use of time-resolved magneto-optic Kerr effect (TR-MOKE) spectroscopy, wherein an optically semi-transparent magnetic transducer (~10 nm of Co/Pt multilayer), on account of its significantly lower thermal mass as compared to Al or Au, affords enhanced sensitivity to the in-plane thermal properties of the substrate underneath. I report on the experimentally measured in-plane conductivities of microtomed COF films grown on a single-layer-graphene (SLG)-coated SiO2 substrates and MOF films deposited on SiO2 substrates using TR-MOKE, in both its concentric and offset beam configurations. The ability to precisely measure the thermal anisotropy in reticular structures will enable a comprehensive understanding of their transport mechanisms, and will facilitate the development of novel organic frameworks for thermal and optoelectronic applications.
Forsta Varme
Detecting Thermal Heterogeneity Using a Two-Sensor Technique
Abstract:
Transient methods of measuring thermal conductivity rely on the assumption that the test material is homogeneous. We show in this study that composites with dispersed fillers which appear as statistically homogeneous may not be thermally homogeneous. To this end, a novel multi-sensor technique was developed to detect thermal heterogeneity. Two sensors are placed on opposite surfaces of the sample tested to measure the surface temperatures with one sensor acting as a heat source. The heat equation is used to calculate effective thermal conductivity and thermal diffusivity values from both sensors. Measurements were made on unfilled and filled samples to demonstrate and contrast the two materials which appear statistically homogeneous but show different thermal homogeneities. The comparison of the obtained sensor values provides insight into the distribution of heat within the sample material throughout the test and could help define criteria where thermal homogeneity assumptions are adequately met.
United States Naval Academy
ITCC Workshop: Arbitrary geometries and confined transducers
Abstract:
In this talk, I will discuss the integration of a numerical, least-squares fitting routine into conventional frequency-domain thermoreflectance (FDTR) measurements to extract the thermal properties of materials and the thermal boundary conductance across interfaces in samples with complex geometric features. The goal of this work is to demonstrate the utility of FDTR for (1) measuring the thermal properties of materials in-situ (i.e., in actual device architectures) and (2) improving the sensitivity of the technique to so-called “buried” interfaces. Critical insights into measurement sensitivity and uncertainty will be discussed, as well as practical limitations associated with such experiments. The presentation will end with a discussion of challenges associated with these measurements and the need for further refinement in future work.
University of Virginia
Thermal and Optical Properties of Rare Earth Oxides for Thermal Barrier Coatings
Abstract:
Rare earth oxides (REOs) show promising thermal properties required of next-generation thermal barrier coatings (TBCs) for ultrahigh temperature applications (1500 K+). TBCs mitigate conductive heating between hot components by reducing thermal conductivity through increased phonon-phonon scattering. New research aims to explore the fundamental mechanisms for this reduction and explore other properties of interest such as melting temperature and emissivity.
In this work, we perform a series of thermal and optical studies via pump-probe thermoreflectance, laser radiometry, and spectroscopic ellipsometry to elucidate the temperature-dependent thermal properties of REOs. With novel laser-based metrology, thermal conductivities, melting temperatures and emissivities of ceramics over 2000 K can be measured nondestructively. Understanding these trends is of utmost importance in choosing REOs that can endure cycling to operating temperatures.
Additionally, through ellipsometry, the lifetimes of optical phonons can be understood. Anharmonic scattering dominates thermal transport at high temperatures so measuring lifetimes with changing temperatures is important to understand fundamental energy transport in REOs. By investigating pertinent physical scattering mechanisms at relevant temperatures, we deconvolute key design considerations for next-generation TBCs.
University of Virginia
Topic 1: Exploring Thermal Transport in Liquid Metal and Eutectic Gallium-Indium Alloys: Implications for Flexible Electronics
Abstract:
Liquid metal and eutectic gallium-indium (EGaIn) alloys represent a promising avenue in the realm of next-generation electronic devices and wearable electronics, owing to their notable advantages such as flexibility, stretchability, and compatibility with unconventional substrates. Leveraging the combined thermal and electrical properties of these materials opens up avenues for novel applications, including flexible sensors, stretchable circuits, and wearable energy harvesters. Given that the efficiency and reliability of electronic devices crucially depend on effective heat dissipation into heat sinks, a thorough understanding of the thermal conductivity of liquid metal, particularly as influenced by processing parameters, becomes imperative for achieving optimized performance.
Traditionally, the Wiedemann-Franz (WF) Law, incorporating a constant Lorenz number (L0 = 2.45 × 10−8 WΩ K−2), has been utilized for determining the thermal conductivity of metallic systems. However, recent scrutiny has cast doubt on the applicability of the Sommerfeld value of the Lorenz number, particularly in thin metallic interconnects and length scales pertinent to contemporary technology. Therefore, a systematic investigation into the thermal conductivity of eutectic gallium-indium Ga0.858In0.142 (14.2 wt. % In), henceforth referred to as EGaIn, employing methods not reliant on electrical resistivity, assumes significance both technologically and scientifically. Moreover, the impact of processing history on the formation and growth of the surface oxide layer of liquid metal and its subsequent effects on thermal boundary resistance remain unexplored territories.
In this study, we present direct measurements of the thermal conductivity of EGaIn utilizing the laser-based pump-probe technique, specifically time-domain thermoreflectance (TDTR). Complementary to these measurements, we infer the electrical resistivity of EGaIn from existing literature, thereby verifying the validity of employing the constant Lorenz number in the WF Law to predict the thermal conductivity of EGaIn. Furthermore, by systematically characterizing the thermal boundary conductance of liquid metal in response to cycling and processing variations, we provide invaluable insights into the intricate interplay between processing conditions, surface oxidation, and thermal transport properties.
Our findings not only contribute to a deeper understanding of the thermal transport characteristics of liquid metal and EGaIn alloys but also inform the refinement of theoretical frameworks such as the WF Law for predicting the behavior of these materials. Moreover, elucidating the influence of processing history on thermal boundary resistance sheds light on potential strategies for optimizing heat dissipation in electronic devices utilizing liquid metal components. Overall, this work underscores the importance of interdisciplinary approaches in advancing the field of thermal management in flexible electronics and engineering for emerging electronic applications.
Topic 2: Measurements of electron and phonon transport and scattering in ferroelectric thin films using ultrafast and infrared spectroscopy
Ferroelectric materials feature a spontaneous electrical polarization that originates from their unit-cell structure, with a spatial orientation that can be switched between stable states when subjected to an external electric field. This characteristic sets them apart as a unique class of materials with enhanced functionality among piezoelectrics. The push toward the miniaturization of piezoelectric sensors and actuators, particularly in microelectromechanical systems (MEMS), along with the integration of ferroelectric properties into integrated circuit (IC) technology and the rise of new applications relying on polarization control, has sparked significant scientific and commercial interest in ferroelectric thin films. Many key ferroelectric materials are oxide perovskites, which often suffer from limitations such as low paraelectric transition temperatures, non-linear displacements, and poor compatibility with technologies like complementary metal-oxide-semiconductor (CMOS) or III-nitride systems. These challenges currently hinder the widespread adoption of ferroelectric functionality in microtechnology.
In this study, we focus on ferroelectric wurtzite nitrides, which exhibit unique electronic and phononic properties that enable dynamic tunability and control over light, charge, spin, and heat. We present characterizing the phonon transport, sound speed, and phononic lifetimes of Al1-xBxN ferroelectric thin films using ultrafast spectroscopy. Additionally, when combined with infrared variable angle spectroscopy ellipsometry (IR-VASE), these methods allow for precise monitoring of scattering rates. Temperature-dependent measurements provide further insights into the changes in optical phonon energies. Understanding these changes will enhance our knowledge of phonon dynamics and could lead to improved ferroelectric materials for next-generation microtechnology applications.
Indian Institute of Technology, Bombay
Investigation of porous metal foam enhanced PCM-based BTMS for CubeSat applications
Abstract:
CubeSats are nanosatellites of standard sizes and form factor. Due to their many advantages, such as low development and launch costs, there has been a surge in the number of CubeSats being launched yearly. However, the CubeSat form factor comes with its own disadvantages, one of which is the high heat dissipation in a small volume, leading to the need for a good thermal control system. Due to the limited power availability in CubeSats, passive thermal control methods are generally preferred. One such passive thermal control method is Phase Change Materials (PCM).
This paper studies the application of a PCM-based Battery Thermal Management System (BTMS) for satellites of the CubeSat form factor. Since weight is a constraint in all space missions, especially in CubeSats, efforts are made towards minimising the weight of the BTMS while maintaining the thermal performance. To this extent, the PCM is embedded in porous metallic foam and its performance is examined. The metallic porous medium not only reduces the weight of the BTMS but also enhances the thermal conductivity and uniformity of heat distribution within the PCM. Numerical simulations are performed to analyse the battery temperatures in orbit with and without the proposed BTMS.
Argonne National Laboratory
Accurate Characterization of Surface Morphology, Strain, and Thermal Expansion Using High-Resolution Scanning X-ray Diffraction Microscopy
Abstract:
Nanoscale bubbles formed between two dimensional (2D) materials and substrates hold significant potentials for applications. Characterizing the bubble profile is essential for understanding its mechanical properties. So far, the most used technique for characterizing bubble profile is atomic force microscope (AFM). Here, we developed a new contact-free method using synchrotron-based scanning X-ray diffraction microscope to measure the bubble profile.
Unlike AFM, which directly measures the bubble profile, our technique measures the rotation of atomic planes, i.e., the gradient of the bubble profile. This metric change increases the measurement sensitivity of the bubble profile, especially the details close to the boundary. To demonstrate the capability of our technique, we characterized bubbles spontaneously formed between WSe2 and SiO2 during the transfer process. Most bubbles we measured demonstrate a plate-like behavior and a linear relation between aspect ratio and radius, consistent with previous studies about small-deflection bubbles using AFM.
Additionally, we observe that the bubbles forming between WSe2 and SiO2 have aspect ratios on the order of 0.001, about 10 times smaller than other systems reported in previous studies. Beyond measuring the bubble profile, our scanning X-ray diffraction microscope can resolve strain as small as 10-5, which holds significant potential for developing novel experimental techniques for measuring thermal expansion and thermal transport properties.
ASTM International
ASTM INTERNATIONAL: Helping our world work better
The presentation will include an overview of ASTM International, the types of ASTM standards, how standards are developed via the ASTM balloting process, and a more detailed look at ASTM Committee E37 on Thermal Measurements.
Lubrizol
Thermophysical properties of fluids – care, collecting, and connecting
Abstract:
Fluids in modern technology are being taxed to perform in applications with delicate balances of viscosity, stability, heat transfer, and system protection. Based on the “three-C’s” of care, collecting, & connecting, this talk will explore the arena of understanding lubricant, non-aqueous fluids, combining thermal, rheological and thermophysical analysis techniques. The fluids discussed in this talk encompass a wide range of applications, including coolants, heat transfer agents, and various petroleum-based packages. Working with fluids that naturally exhibit a relatively narrow range of stability and thermophysical properties requires care. Which techniques should be used? What are the characteristics and limitations of each fluid? Such a narrow range of values requires a large volume of samples for a deeper understanding, therefore collecting this extensive data requires efficiency and a high level of checks and balances. How do we know we have the right answer? How much variation do we really see? “Connecting” is how we use this knowledge to enable communications with customers and project leaders. What matters most? What alterations can be made? Educating them of the holistic view and the possibilities drives future successes.
Glenn T. Seaborg Institute, Idaho National Laboratory
Low-Temperature CDW of α-U Crystals Probed by High-Resolution Dilatometry
Abstract:
Phase diagram of U contains three crystallographically different phases below the melting point. The α-U is the allotropic modification, which is stable at room temperature and ambient pressure. However, at low temperatures three charge density waves transitions (CDW) have been observed (the phases are labeled α1, α2, and α3). The first transition takes place at 43 K (α1), the second at 38 K (α2), and the last one stabilizes below 25 K (α3). The structure undergoes complex modifications below the transitions. Atoms exhibit small displacements along all three of the orthorhombic axes.
Anisotropy of the structural changes is one of the factors which limits application of α-U materials and requires better fundamental understanding. Despite the large experimental and theoretical effort, the nature of these transitions is still elusive, but it is believed to be associated with the unique coupling of 5f states, residing in the vicinity of the Fermi level, and lattice vibrations. Here we present detailed experimental and theoretical studies of low-temperature thermal, thermodynamic, and electronic transport properties of the high-quality single crystals of α-U, across the CDW transitions.
University of Virginia
Investigating size effects atf the thermal conductivity plateau of amorphous silica
Abstract:
The future of modern technology relies on understanding and developing materials useful for the quantum computing revolution. Silica (SiO2) is an ever present interlayer in most electronic devices due to the ubiquity of silicon transistors. However, at the low temperature extremes of next generation quantum qubits, the thermal dissipation and isolation capabilities of these thin silica films is not fully agreed on. Due to the amorphous nature of Silica, the thermal conductivity at low temperatures (<20K) exhibits a plateau, where the thermal conductivity becomes constant with respect to temperature. There has been extensive work on the theoretical and experimental investigation of this regime, however the effects of film thickness, or size effects are often overlooked. In this work, we utilize thermal reflectivity techniques in the frequency domain as well as in the steady state, to understand how size effects impact the thermal conductivity plateau of amorphous SiO2 at ultralow temperatures.
Current state of the art optical thermometry platforms for measuring these thermal properties are the pump-probe techniques time- and frequency-domain thermoreflectance, TDTR and FDTR, respectively. These techniques are often claimed not to be suitable at ultralow temperatures due to the fact that the measurement relies on modulated temperature rises. Our proposed approach of low duty cycle FDTR and low-power steady state thermoreflectance (SSTR) will overcome these limitations. SSTR is also a pump-probe technique, but unlike TDTR, it uses continuous wave laser sources to heat and probe the surface temperature change of a material as a function of laser power in a low frequency, “nearly-DC” regime. By limiting the pump powers used in SSTR as well as the duration of the heating even in FDTR we are able to restrict the thermal perturbation required for measurement to nearly 3K. Further, since SSTR is a steady-state technique, it is a direct measure of thermal conductivity, and is not subjected to uncertainties and errors due to transient heating of thermal masses and heat capacity assumptions, and the combined approach with FDTR allows for isolation of these thermal parameters which obfuscate the low temperature trends of materials.
University of Virginia
Investigating Thermal and Optical Properties in Rare Earth Zirconates for Radiative Barrier Coatings
Abstract:
Rare earth zirconates show promising thermal and optical properties required of next generation radiative barrier coatings (RBCs) for ultrahigh temperature (1200 oC+) applications. A fundamental mode of heat transfer that has been neglected in current barrier coatings is radiative heating between hot components. New research aims to mitigate both conductive and radiative heating by doping standard barrier coating materials with rare earth metals that are optically opaque in the spectral range of the emitted radiation.
In this work, we perform a series of thermal and optical studies via pump-probe thermoreflectance, laser radiometry, and spectroscopic ellipsometry to elucidate temperature-dependent thermal conductivities and optical properties of rare earth zirconates. With a new laser-based metrology, thermal conductivities and emissivities of ceramics over 2000 oC can be measured and the underlying mechanism of increasing gray-like, near-infrared emissivity can be understood. Additionally, through ellipsometry, we extract the lifetimes of optical phonons to discern scattering mechanisms from multi-cationic doping. By investigating pertinent physical scattering mechanisms and optical properties, we deconvolute key design considerations for next generation RBCs.
China Institute of Atomic Energy
Material Relocation Test Study of Pellet to Cladding Interaction in Fast Reactor Design
Abstract:
During Pellet to Cladding Interaction phenomenon, the confirmed material relocation due to thermal melting and thermal diffusion is studied based on ASTM E793, ASTM E2585 and ASTM E1461. These kinetic parameters of the PCI can be established into the fuel center-line melting criterion for assuring that the axial or radial relocation of molten fuel would not be allowed to contact with the cladding in Fast Reactor design.
Nazarbayev University
Nano- and micro-scale phonon-mediated thermal transport in swift heavy ion irradiated crystalline insulators
Abstract:
Understanding heat conduction on micro- and nano- meter spatial scales in solid-state materials is very important for thermal management encountered in numerous applications involving, but not limited to, nuclear and fission energy, thermoelectric, electronic and opto-electronic devices. We will review our recent results on phonon-mediated thermal transport in swift heavy ion (SHI) irradiated single crystalline metal oxides [1 – 4] and alkali halides [5], as well as in polycrystalline nitride ceramics for heat management in nuclear energy applications. SHI-induced nano-patterning can be employed for making novel thermal functional materials. Heat conduction measurements were implemented by advanced thermal metrology techniques probing heat propagation in SHI irradiated crystalline insulators at nanoscale and microscale depths by picosecond time-domain thermoreflectance with MHz modulated rates and by continuum wave laser-based frequency- and spatial-domain thermoreflectance with kHz modulation rates, respectively. Measured thermal conductivity values were found to be in agreement with molecular dynamics and semi-analytical phonon thermal transport modeling. New results revealed intriguing heat propagation phenomena associated with the presence of point and extended (latent track) radiation defects associated with electronic and nuclear energy losses encountered by impinging SHIs.
Idaho National Laboratory
Heat transfer or Novel Methods of Measurement
Abstract:
Thermal transport properties are among the most important physical properties in energy related applications as they directly tie to energy transport efficiency. Moreover, they are sensitive to the existences of defects and thus can be used to characterize microstructure. Here we reported the experimental approaches of using two radiometry-based instruments, Photothermal Radiometry (PTR) and Lock-in Infrared Thermography (LIT), to rapidly measure thermal properties and characterize the microstructure defects, such as porosities, of Advanced Manufacturing and Additive Manufacturing produced materials. The testing samples are manufactured with designed porosities using Advanced Manufacturing technology Electric Field Assisted Sintering (EFAS, or Spark Plasma Sintering, SPS), and Additive Manufacturing technologies Directed Energy Deposition (DED) and Laser Powder-Bed Fusion (LPBF). The progress of developing PTR/LIT based in-situ processing monitoring capabilities will also be presented.