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At least 37 records · Page 2

Implementation of WBG devices in circuits - Electric Drive Technologies Project (Final Technical Report)

The objective of the project is to ensure that SiC devices are reliable and rugged as required in automotive applications for operational life of 300,000 hrs and create new device designs to address various weaknesses in currently available commercial devices. OSU has worked closely with SUNY Polytechnic. OSU has carried out the reliability and ruggedness evaluations of commercial devices as well as those fabricated by SUNY Polytechnic, discussed the results with SUNY Poly, and collaborated with the PI at SUNY Poly to improve the designs with respect to reliability/ruggedness. OSU work focused on reliability/ruggedness evaluation of SiC devices by individually testing them and then evaluate them in a 10 kW, 3 phase inverter system built with a specific purpose of stressing devices using realistic drive cycles such as a 10-minute hill climb. It should be noted that the primary purpose of the 10 kW inverter is to provide a platform for stressing the SiC devices under accelerated but realistic drive conditions.

33 ADVANCED PROPULSION SYSTEMS

Wafer-Scale MgB 2 Superconducting Devices

Progress in superconducting device and detector technologies over the past decade has realized practical applications in quantum computers, detectors for far-infrared telescopes, and optical communications. Superconducting thin-film materials, however, have remained largely unchanged, with aluminum still being the material of choice for superconducting qubits and niobium compounds for high-frequency/high kinetic inductance devices. Magnesium diboride (MgB 2 ), known for its highest transition temperature (T c = 39 K) among metallic superconductors, is a viable material for elevated temperature and higher frequency superconducting devices moving toward THz frequencies. However, difficulty in synthesizing wafer-scale thin films has prevented implementation of MgB 2 devices into the application base of superconducting electronics. Here, we report ultrasmooth (<0.5 nm root-mean-square roughness) and uniform MgB 2 thin (<100 nm) films over 100 mm in diameter and present prototype devices fabricated with these films demonstrating key superconducting properties including an internal quality factor over 10 4 at 4.5 K and high tunable kinetic inductance in the order of tens of pH/sq in a 40 nm thick film. This advancement will enable development of elevated temperature, high-frequency superconducting quantum circuits, and devices.

Boron

Halide perovskite-polymer composite film for bright and stable light-emitting devices

Stability is the primary hindrance for the application of halide perovskite material in light-emitting devices, solar cells, and other devices. In this work, halide perovskite and polymer composite film have been prepared for stable and bright light-emitting devices. Pure-phase Cs4PbBr6 crystals have been synthesized, and their photoluminescence (PL) properties and fluorescence lifetimes have been investigated. The Cs 4 PbBr 6 crystals exhibited high uniformity but underwent rapid photodegradation under light irradiation. To address this issue, we prepared bright light-emitting devices using composite of Cs 4 PbBr 6 crystals and polyethylene oxide (PEO) as the emission layer. The aim was to improve the optical and physical properties of halide perovskites, such as photodegradation and stability. PEO, with its excellent film-forming ability, created a uniform and dense film on the halide perovskite surface, filling microscopic defects and providing a protective barrier. FTIR, morphology, and PL analyses confirmed the protective role of the halide perovskite and polymer composite film. The composite film light-emitting devices demonstrated improved stability and higher PL brightness, with a peak brightness approaching 3 × 10 8 cd/m 2 , which was approximately 75% higher than the pure halide perovskite devices.

Composite film

Direct comparison of gamma, electron beam and X-ray radiation effects on the polymers of a pulsed lavage device

Gamma radiation used for sterilization of medical devices is challenged by cobalt-60 supply and commercial capacity. To maintain a robust radiation sterilization marketplace for the rapidly growing single-use medical device industry, investigation of potential alternatives to gamma technology, such as electron beam (e-beam) and X-ray technology, is critical. In this work, we directly compare the effects of radiation source and absorbed dose level on the polymeric materials and function of a commercial pulsed lavage device used for wound care. Product functionality, polymer mechanical, and polymer optical properties were evaluated using standard methods and input from the device manufacturer. Test results show that functionality of the product was not inhibited by radiation although the battery in the device exposed to X-ray exhibited greater voltage loss compared to batteries in products exposed to gamma or e-beam. Statistically significant differences between gamma and e-beam exposure and between gamma and X-ray exposure were also observed for product appearance in terms of yellowness index of several of the polymers considered. Overall, the results of this study support the viability of e-beam and X-ray radiation technologies as alternatives to cobalt-60 gamma technology for sterilization of the single-use pulsed lavage medical device investigated.

Electron beam

Spatiotemporal Thermal Coupling in VO 2 Device Arrays

Correlated oxides such as VO 2 exhibit an electrically driven insulator–metal transition (IMT) that underlies their promise for neuromorphic and memory devices. Yet the IMT is not a uniform bulk process but a spatiotemporal phenomenon in which local heating nucleates filaments, contracts or dissolves them with the electric field, and couples to the environment. In this work, we directly image the VO 2 IMT dynamics by mid-wave infrared, thermography synchronized with electrical transport, resolving device temperature with micrometer spatial and microsecond temporal resolution. At the single-device level, we capture the full cycle of filament nucleation, contraction, and relaxation during current/voltage-driven resistive switching. At the array level, we show that heat propagates across etched gaps with an effective length scale of ∼131 µm, enabling cooperative behaviors among electrically isolated devices. Short-range distanced devices exhibit mutual filament attraction and sequential dissolution, while long-range distanced devices differentiate into distinct roles: drivers that initiate switching, cooperative responders that undergo assisted self-oscillations, and passive reporters that record the thermal field. Furthermore, these results reframe thermal crosstalk, long regarded as parasitic, as an intrinsic coupling channel and design principle for organizing collective switching behaviors, with direct implications for emergent circuit functionality in neuromorphic and unconventional computing architectures.

coupling

In-device Battery Failure Analysis

Lithium-ion batteries are indispensable power sources for a wide range of modern electronic devices. However, battery lifespan remains a critical limitation, directly affecting the sustainability and user experience. Conventional battery failure analysis in controlled lab settings may not capture the complex interactions and environmental factors encountered in real-world, in-device operating conditions. Here, this study analyzes the failure of commercial wireless earbud batteries as a model system within their intended usage context. Through multiscale and multimodal characterizations, the degradations from the material level to the device level are correlated, elucidating a failure pattern that is closely tied to the specific device configuration and operating conditions. The findings indicate that the ultimate failure mode is determined by the interplay of battery materials, cell structural design, and the in-device microenvironment, such as temperature gradients and their fluctuations. This holistic, in-device perspective on environmental influences provides critical insights for battery integration design, enhancing the reliability of modern electronics.

36 MATERIALS SCIENCE

High-resolution high-throughput spatiotemporal strain imaging reveals loss mechanisms in a surface acoustic wave device

Surface acoustic wave devices are key components for processing radio frequency signals in wireless communication because these devices offer simultaneously high performance, compact size and low cost. The optimization of the device structure requires a quantitative understanding of energy conversion and loss mechanisms. Here we use stroboscopic full-field diffraction x-ray microscopy to reveal an unanticipated acoustic loss in a prototypical one-port resonator device. A non-uniform acoustic excitation in the active area was responsible for the substantial end and side leakages observed at the design frequency. Quantitative analysis of the strain amplitude using a wave decomposition method allowed the determination of several key device parameters. This high-resolution high-throughput spatiotemporal strain imaging technique is more generally applicable to the study of dynamic strain modulation in nanoscale acoustic, electronic, optical and quantum devices. The high sensitivity allows precise measurement of the strain modulation with picometer-scale amplitude.

Zhou, Tao [ESRF - The European Synchrotron, Grenob

Integration of multiple coinflip devices for high-quality random sampling

Artificial intelligence, scientific computing, and probabilistic computing use random sampling to approximate solutions to various problems, with larger models requiring a substantial quantity of random numbers. To generate the required vast quantity of random numbers at high rates, we explore so-called “coinflip” devices, which are stochastic microelectronic devices ideally capable of independently generating random bits with a tunable weight at a high rate. However, coinflip devices are inherently analog and demonstrate nonidealities, like temperature dependence and drift, that can introduce determinism into the outputs. We present important considerations for building systems of multiple coinflip devices to produce high-quality bitstreams with low error and little dependency on previous bits. Using tunnel diodes as coinflip devices, we implement a control loop to adapt to temperature dependence and generate fair bitstreams with each device. While this can lead to dependencies between bits in a single bitstream, we demonstrate that combining results generated in parallel with individual tunnel diodes can produce fair and unpredictable bitstreams. The suitability of these bitstreams for use in probabilistic computing is then demonstrated through a Monte Carlo approximation of π.

Taylor, Brady Garland [Sandia National Laboratorie

Countering Weapons of Mass Destruction Office (CWMD) Data Categorization Study: Chemical, Biological, Radiological, and Nuclear (CBRN) Detection Device Data

Pacific Northwest National Laboratory (PNNL) seeks to address critical questions related to chemical, biological, radiological, and nuclear (CBRN) detection devices. This research aims to enhance the security and understanding of these devices by investigating various aspects of their identification, communication, and functionality. The primary focus is on network security, malware detection, device identification, and intelligence gathering. CBRN data can be categorized in various ways depending on the purpose of CBRN detection devices and the specific context of the applications for analysis. Criteria that can be used to assist in this effort include but are not limited to data type, data protocol, source/destination, application, time, security, and content. This study will inform additional paths for data classification, data profiling, data mapping, and data modeling. This will help the Countering Weapons of Mass Destruction Office (CWMD) better understand their data and make informed decisions based on the insights gained from this study and their application. The CBRN Data Categorization study will include the identification of 5–10 different CBRN detection devices with unique characteristics for assessing and analyzing the data that is being produced by and transmitted from these devices.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF

Heavy-Duty Hydrogen Station Equipment Performance Device (HD HyStEP) Specifications and Design Considerations

The original Hydrogen Station Equipment Performance (HyStEP) device was commissioned in 2015 and was critical for the rapid validation of light-duty (LD) hydrogen fueling stations. As applications for hydrogen as a heavy-duty (HD) transportation fuel continue to grow, new heavy-duty stations are being developed to fuel these vehicles that require larger onboard storage tank systems to meet HD transportation demands and drive cycles. The differences in size and geometry from LD vehicles have driven the creation of new hydrogen fueling protocols that will enable safe and economical fueling of HD vehicles. With the new requirements that are set out in HD fueling protocols like SAE J601-5, a new HyStEP-like device is needed to evaluate the capabilities of high-flow hydrogen stations to fuel HD vehicles to the new protocol standard. To create a heavy-duty HyStEP (HD HyStEP) device, an effort has been undertaken to evaluate the requirements that would form the basis for the design of a successful HD HyStEP device. The primary design goal of this HD HyStEP device is its capability of following a test methodology similar to what is outlined in CSA HGV 4.3, which guides the validation of LD fueling dispensers but with adjustments to verify adherence to the HD fueling protocols (SAE J2601-5) for 70 MPa and 35 MPa pressure class vehicles rather than the LD fueling protocols (SAE J2601). The design presented here aims to provide information that enables the creation of an HD HyStEP device that achieves the primary design goal while being informed by the years of experience from the current HyStEP operators.

08 HYDROGEN

InP- and GaAs-Based 0.6 eV GaInAs Devices for Thermophotovoltaics and Laser Power Conversion

Emerging applications such as thermal energy grid storage, waste heat recovery and portable power generation require efficient thermophotovoltaic (TPV) converters tuned to temperatures near 1000 Degrees Celsius or below. Metamorphic GaInAs with larger lattice constants than InP present a promising option for these needs. The ability to grow these devices on GaAs substrates instead of more expensive InP would enhance the scalability of these devices. In this talk, we present inverted metamorphic Ga0.3In0.7As photovoltaic converters with sub-0.60 eV bandgaps grown on InP and GaAs substrates. These devices are realized using InAsP or GaInP/InAsP compositionally graded buffers which exhibit threading dislocation densities of 1.3 +/- 0.6 x 106 cm-2 and 8.9 +/- 1.7 x 106 cm-2 on InP and GaAs, respectively. Despite this difference in defect density, the devices generate similar open-circuit voltages of 0.386 V and 0.383 V, respectively, under irradiance producing a short-circuit current density of -10 A/cm2, with bandgap-voltage offsets of 0.20 and 0.21 V. We estimate their thermophotovoltaic efficiency using these measurements coupled with broadband reflectance measurments. The InP-based cell is estimated to yield 1.09 W/cm2 at 1100 Degrees Celsius vs. 0.92 W/cm2 for the GaAs-based cell, with TPV efficiencies of 16.8 vs. 9.2%. Both devices are limited by sub-bandgap absorption, which we assess largely occurs in the graded buffers. We estimate that the 1100 Degrees Celsius thermophotovoltaic efficiencies would increase to 24.0% and 20.7% in structures with the graded buffer removed, if previously demonstrated reflectance is achieved. These devices also have application as laser power converters in the 2.0-2.3 um atmospheric window. We estimate efficiencies of 36.8% and 32.5% under 2.0 um monochromatic irradiance of 1.86 W/cm2 and 2.81 W/cm2, respectively.

ENGINEERING,MATERIALS SCIENCE,SOLAR ENERGY

Wide bandgap optical switch circuit breaker for controlling propagation of current therethrough a wide bandgap optical device

A high-voltage switch is adapted for use as a medium-voltage direct current circuit breaker, which provides a low-cost, small-footprint device to mitigate system faults. In one example, a method for operating a wideband optical device includes illuminating the wide bandgap optical device with a light within a first range of wavelengths and a first average intensity, allowing a current to propagate therethrough without substantial absorption of the current, illuminating the wide bandgap optical device with light within the first range of wavelengths and a second average intensity that is lower than the first average intensity to allow a sustained current flow though the wide bandgap optical device, and illuminating the wide bandgap optical device with light within a second range of wavelengths to stop or substantially restrict propagation of the current through the wide gap material.

Voss, Lars F.

Portable and Cost-Effective Device for Reliable Detection of Counterfeit and Non-compliant Refrigerants in Diverse Applications

Counterfeit refrigerants pose significant challenges to safety, system reliability, and operational effectiveness due to their harmful contaminants or incompatible chemical compositions. Utilizing these noncompliant products can lead to reduced efficiency, equipment failures, and expensive repairs. Additionally, heightened demand for alternative refrigerants during the industry's transition has created supply gaps, enabling counterfeit products to proliferate. Accurate detection and analysis tools are therefore essential to verify refrigerant authenticity and ensure system integrity in diverse applications. This paper presents the development of a portable device designed for reliable identification and detailed analysis of refrigerant composition. By integrating precision gas sampling, controlled pressure regulation, and automated sensor technology, the device not only detects deviations from standard refrigerant properties but also provides a comprehensive composition breakdown. Pre-calibrated sensors measure the refrigerant gas to identify specific concentrations and contaminants, with an intuitive LED-based indicator system ensuring quick interpretation of results. The user-friendly interface enables operators to select refrigerant types for targeted testing, further enhancing accuracy and usability for field technicians. Comprehensive testing was conducted on mildly flammable A2L refrigerants, showcasing the device’s robustness and adaptability in analyzing composition and detecting discrepancies. The device demonstrated consistent accuracy across a range of refrigerant samples, affirming its reliability in diverse operational environments. Its design minimizes contamination risks during sampling and provides detailed composition results within 90 seconds, ensuring efficient and precise analysis. With a projected price point under $150, the proposed solution delivers affordability alongside its lightweight portability and straightforward operation. Unlike complex and costly alternatives, such as gas chromatography systems, this device provides an accessible option for technicians, customs personnel, and industry operators in need of quick and effective refrigerant verification. Compatible with both current formulations and emerging refrigerant technologies, the device addresses critical counterfeit detection needs across a range of applications. By delivering accurate composition analysis and counterfeit identification, this innovation enhances system performance, safety, and operational reliability in crucial industries.

Cheekatamarla, Praveen [ORNL] (ORCID:0000000248827

High-Resolution Full-Field Structural Microscopy of the Voltage-Induced Filament Formation in VO 2 -Based Neuromorphic Devices

In order to make neuromorphic functions in memristive devices more efficient, information about the structural properties of filament formation at the micro- and mesoscopic scales is necessary. Despite extensive research on VO 2 , a key material due to its filament formation, local operando structural measurements remain challenging and often involve destructive specimen preparation and long rastering times, greatly limiting the scope of experimental studies. Utilizing dark-field X-ray microscopy (DFXM), a fullfield imaging modality, structural signatures of the filament formation process operando are revealed in VO 2 devices. DFXM experiments illustrate that rutile filaments contain isolated monoclinic clusters, indicating structural nonuniformity interior to the filament. The formation of the rutile phase beneath device electrodes was shown to precede filament development, followed by the formation of filament paths guided by nucleation sites within the device. Finally, a medium-term (<30 min) memory mechanism is observed in VO 2 , mediated by sites within the device gap that tend to switch at significantly lower voltages after electrical cycling, a tendency that persists through a brief thermal reset. High spatial resolution, large field-of-view, structure selectivity, and fast signal acquisition of DFXM provided insight into structural features of the filamentary channel and surrounding regions during voltage cycling.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND

Enhanced power density in zero-vacuum-gap thermophotovoltaic devices

Thermophotovoltaic (TPV) devices, which convert infrared thermal radiation from a hot emitter into electricity, hold great promise for applications in energy storage and waste heat recovery. While recent advancements have developed TPV devices with high efficiency, much less attention has been focused on improving the power density. Current TPV methods face challenges in significantly boosting the power density using emitters at very high temperatures (>2000 °C) or using complex, costly architectures such as near-field TPV. Here, we present the first experimental demonstration of a novel far-field TPV concept called “zero-vacuum-gap TPV” that eliminates the vacuum or gas-filled gap in conventional designs. By incorporating a high-index, infrared-transparent, and thermally insulating fused quartz spacer, we achieved a two-fold increase in power density compared to the far-field counterpart under identical conditions. Notably, in our experiment, the zero-vacuum-gap far-field design transforms a less-optimized, low-power-density far-field device into one with one of the highest power densities reported at moderate temperatures (700–1100 °C). Moreover, our measurements using a graphite emitter surpass the blackbody limit for gap-integrated far-field devices and match the performance of near-field TPV devices with an ultrathin 200-nm gap. Our findings suggest that zero-vacuum-gap TPV offers potential for cost-effective, scalable manufacturing using current technologies. Additionally, our modelling predicts that further power enhancements over one order of magnitude are possible with other spacer materials.

14 SOLAR ENERGY

Evaluation of Converter Performance Considering Static and Dynamic Device Part-to-Part Variability

This paper presents a methodology to incorporate and analyze the impact of semiconductor device part-to-part variation on power converter performance. By integrating extensive static and dynamic device characterization data with an automated compact model generation process that reflects manufacturing variability, device models with inherent variability features are utilized in converter simulations for a comprehensive assessment of performance impacts. The traditional converter performance evaluation process typically yields fixed efficiency values, often dismissing the inherent part-to-part variability caused by the manufacturing process of semiconductor devices. To address this limitation, a large population of devices was characterized to capture variations in static parameters-such as transfer, output, and capacitance characteristics-as well as dynamic behaviors, including switching losses. This data-driven approach enables the development of individual compact models, which were then integrated into converter simulations to evaluate efficiency ranges rather than single point estimated values. The converter simulation results show that part-to-part component variation can lead to significant efficiency deviations, exceeding several percentage points in high-power conversion applications. By offering a more accurate representation of converter behavior under real-world manufacturing conditions, this methodology enables designers to anticipate performance variability, improving the robustness of power converter designs.

device characterization

Fabricated devices for performing bacterial-fungal interaction experiments across scales

Diverse and complex microbiomes are found in virtually every environment on Earth. Bacteria and fungi often co-dominate environmental microbiomes, and there is growing recognition that bacterial-fungal interactions (BFI) have significant impacts on the functioning of their associated microbiomes, environments, and hosts. Investigating BFI in vitro remains a challenge, particularly when attempting to examine interactions at multiple scales of system complexity. Fabricated devices can provide control over both biotic composition and abiotic factors within an experiment to enable the characterization of diverse BFI phenotypes such as modulation of growth rate, production of biomolecules, and alterations to physical movements. Engineered devices ranging from microfluidic chips to simulated rhizosphere systems have been and will continue to be invaluable to BFI research, and it is anticipated that such devices will continue to be developed for diverse applications in the field. This will allow researchers to address specific questions regarding the nature of BFI and how they impact larger microbiome and environmental processes such as biogeochemical cycles, plant productivity, and overall ecosystem resilience. Devices that are currently used for experimental investigations of bacteria, fungi, and BFI are discussed herein along with some of the associated challenges and several recommendations for future device design and applications.

59 BASIC BIOLOGICAL SCIENCES

Organic Nano-Junctions: Linking Nanomorphology and Charge Transport in Organic Semiconductor Nanoparticles for Organic Photovoltaic Devices

In this study, innovative nanoscale devices are developed to investigate the charge transport in organic semiconductor nanoparticles. Using different steps of lithography techniques and dielectrophoresis, planar organic nano-junctions are fabricated from which hole mobilities are extracted in a space charge-limited current regime. Subsequently, these devices are used to investigate the impact of the composition and morphology of organic semiconductor nanoparticles on the charge mobilities. Pure donor nanoparticles and composite donor:acceptor nanoparticles with different donor compositions in their shell are inserted in the nanogap electrode to form the nano-junctions. The results highlight that the hole mobilities in the composite nanoparticles decrease by two-fold compared to pure donor nanoparticles. However, no significant change between the two kinds of composite nanoparticle morphologies is observed, indicating that conduction pathways for the holes are as efficient for donor proportion in the shell from 40% to 60%. Organic photovoltaic (OPV) devices are fabricated from water-based colloidal inks containing the two composite nanoparticles (P3HT:eh-IDTBR and P3HT:o-IDTBR) and no significant change in the performances is observed in accordance with the mobility results. Through this study, the performance of OPV devices have been successfully correlated to the transport properties of nanoparticles having different morphology via innovative nanoscale devices.

42 ENGINEERING