Thermal annealing of radiation-induced degradation, especially at lower temperatures, requires an impractically long duration. This study investigates the efficacy of room-temperature electron wind force (EWF) annealing as a post-irradiation recovery treatment. Cascode GaN high-electron-mobility transistors (HEMTs) were exposed to gamma radiation doses of up to 10 Mrad.approximately 10 times higher than the average reported in the literature.resulting in significant degradation of their output and transfer characteristics. Our non-thermal annealing process appreciably mitigated radiation-induced damage within minutes. In contrast, similar studies in the literature required orders of magnitude more time and/or higher temperatures, even for lower doses (.500 Krad). These findings highlight the potential of EWF annealing as an in-operando treatment to enhance the resilience of GaN devices in radiation-intensive environments.

We present the Plan for Robust and Accurate Potentials (PRAPs), a software package for training and using moment tensor potentials (MTPs) in concert with the Machine Learned Interatomic Potentials (MLIP) software package. PRAPs provides an automated workflow to train MTPs using active learning procedures, and a variety of utilities to ease and improve workflows when utilizing the MLIP software. PRAPs was originally developed in the context of crystal structure prediction, in which one calculates convex hulls and predicts low energy metastable and thermodynamically stable structures, but the potentials PRAPs develops are not limited to such applications. PRAPs produces two potentials, one capable of rough estimates of the energies, forces and stresses of almost any chemical structure in the specified compositional space – the Robust Potential – and a second potential intended to provide more accurate descriptions of ground state and metastable structures – the Accurate Potential. We also present a Python library, mliputils, designed to assist users in working with the chemical structural files used by the MLIP package.

Ultra-wide-bandgap (UWBG) semiconductors are promising for power electronics, but high-breakdown diodes often suffer from high turn-on voltages and defect-related performance limits, requiring high-temperature processing. This work demonstrates that electron wind force (EWF)-assisted processing significantly reduces the turn-on voltage of aluminum nitride (AlN) diodes at room temperature, eliminating the need for thermal annealing. Across four room-temperature devices, the average turn-on voltage decreases from 2.34 +/- 0.23 to 1.23 +/- 0.38 V after EWF processing, while the forward current at 5 V increases from 78.23 +/- 20.75 pA to 110.4 +/- 20.8 pA. Infrared thermal imaging during processing shows that the sample temperature remains close to ambient, supporting the low-thermal-budget nature of the approach. High-frequency capacitance-voltage measurements reveal a systematic modification of junction electrostatics, indicating reorganization of electrically active defect states within the depletion region rather than changes in bulk conductivity. Complementary Raman spectroscopy shows a modest narrowing of the E2(high) phonon linewidth, from 5.04 to 4.82 cm-1, reflecting reduced defect-related phonon scattering. Time-dependent measurements show partial relaxation of the turn-on voltage shift after four days, suggesting that the EWF-induced modification is metastable rather than conventional bulk lattice annealing. Together, these results show that room-temperature EWF processing provides an electrically driven route to lowering the turn-on voltage of AlN diodes, addressing a key limitation in UWBG rectifiers.

Understanding grain-boundary mobility during spark plasma sintering can enable microstructure control in high-entropy carbides, yet quantitative grain-growth kinetics remain scarce. In this work, grain growth kinetics and densification behavior were investigated for single-phase fully dense (Cr,Mo,Ta,V,W)C1-δ high-entropy carbide ceramics. Specimens were densified by spark plasma sintering for a constant dwell time of 10 min at temperatures between 1750 °C and 1950 °C to isolate the role of temperature on microstructural evolution. Increasing sintering temperature produced grain growth and increased lattice parameter, while maintaining a single-phase rock salt structure. Elemental mapping showed a progressive reduction of Ta segregation with increasing sintering temperature, suggesting enhanced chemical homogenization at elevated temperatures. Grain growth kinetics were analyzed using a normal grain growth model with an assumed growth exponent of n=3, physically reasonable for grain-boundary-controlled growth influenced by solute and vacancy pinning. Arrhenius analysis of the growth factor yielded an apparent activation energy of approximately 620 kJ mol-1, comparable to diffusion-controlled processes in refractory transition-metal carbides. Densification curves revealed rapid consolidation prior to reaching the peak temperature followed by temperature-dominated grain coarsening. These results establish quantitative relationships between densification temperature, grain growth, and diffusion kinetics in a carbide system, providing insight into the microstructural stability of high-entropy, ultra-high-temperature carbide ceramics.

ABSTRACT High‐entropy carbides are promising candidates for extreme‐temperature environments, but their grain‐boundary chemistry remains difficult to resolve because segregation involves both chemical disorder and finite‐temperature configurational sampling. Here, we quantify temperature‐dependent grain‐boundary segregation in high‐entropy carbides using a universal message‐passing atomic cluster expansion (MACE) machine learning interatomic potential combined with a hybrid Monte Carlo–molecular dynamics workflow. A 53.1 symmetric tilt grain boundary was sampled for six representative high‐entropy carbide compositions containing group IV, V, and VI transition metals at 300 and 2000 K. Element‐resolved metal‐sublattice composition profiles reveal composition‐dependent segregation modes. Several chemistries exhibit selective near‐boundary enrichment by one or two dominant metals, including Ti/Zr, Mo/Zr, W/Zr, and Cr/Zr motifs, whereas shows persistent multi‐element co‐segregation. Increasing temperature broadens the segregation profiles and expands the chemically perturbed interfacial region, with secondary metal species contributing more strongly to the near‐boundary composition at 2000 K. A Cr‐containing composition shows the most pronounced high‐temperature response, where Cr‐rich segregation is accompanied by boundary broadening, chemical heterogeneity, and structural disordering. These results show that grain‐boundary segregation in high‐entropy carbides does not follow a single universal trend, but instead depends strongly on carbide chemistry and temperature.

Annealing of electronic devices is performed at elevated temperatures since conventional wisdom suggests that only thermal energy can mobilize and annihilate the defects that are grown in the semiconductor or induced by device processing steps. To demonstrate that elevated temperature is not a prerequisite for annealing, commercially available 1700 V silicon carbide MOSFETs were first intentionally degraded using Co-60 gamma irradiation to a total dose of 1 Mrad(Si). A direct current was then applied to induce an electron wind force—a mechanical stimulus arising from the transfer of electron momentum to lattice defects. Throughout the treatment, the device junction temperature was maintained at ∼20 °C by actively cooling the chamber to −35 °C using nitrogen gas flow. Post-irradiation transfer, output, capacitance–voltage, and drain-lag responses revealed dose-dependent negative threshold voltage shifts and enhanced drain current due to positive oxide charge buildup. Remarkably, the applied electron flux provided sufficient momentum to liberate trapped carriers and reconfigure metastable defects, enabling ∼98–100% recovery of threshold voltage, drain current, and capacitance across all irradiation doses. These findings indicate that high temperature may not be the only driving force for defect mitigation in conducting and semiconducting materials, thereby impacting the resilience of power electronics in aerospace and nuclear applications.

Diamond-based devices are promising for operation in radiation environments due to their wide bandgap and strong atomic bonding. In this work, the effects of Co-60 gamma irradiation to a total dose of 1 Mrad on the electrical characteristics and carrier dynamics of diamond Schottky and indium-tin oxide (ITO)/boron doped diamond heterojunction rectifiers are investigated. The rectifiers were exposed to gamma radiation with photon energies of 1.17 and 1.33 MeV, where ionization dominates over displacement damage. The Schottky diodes exhibit minimal changes in both forward and reverse current characteristics after irradiation, indicating stable metal/diamond interfaces. In contrast, the heterojunction devices show a positive shift of forward IV around the diode turn-on voltage and an increased ideality factor, suggesting modification of charge accumulation in the ITO. The changes in electrical characteristics for both rectifiers are reversible by application of short forward current pulses during repeated measurement of the current–voltage characteristics at room temperature. There are no permanent total ionizing dose effects present in the rectifiers under the irradiation conditions used in this study. Reverse current shows only minor variation for both types of rectifiers, confirming the absence of significant bulk leakage paths. Reverse recovery measurements reveal a reduction in recovery time after irradiation, attributed to decreased carrier lifetime and reduced stored charge due to radiation-induced traps. The extracted carrier concentration from the capacitance–voltage analysis changes only slightly from 1.23 × 10 16 to 1.20 × 10 16 cm −3 after irradiation confirming that gamma irradiation does not induce measurable degradation in bulk electrical properties under the irradiation conditions used in this study. While isolated Frenkel defects or other point defects may be generated during gamma irradiation, their concentration is evidently too low to produce measurable changes in carrier concentration or leakage current. The corresponding carrier removal rate is on the order of ∼0.1 cm −1 . This small variation indicates that gamma irradiation does not significantly affect the bulk carrier concentration in diamond. These results indicate that gamma irradiation primarily affects carrier dynamics and interface properties, while the bulk diamond remains largely unaffected. Thus, diamond-based rectifiers may be well-suited to harsh terrestrial and space radiation applications if appropriate bias sequences are implemented to reverse the radiation-induced changes.

Gallium nitride-based electronics are expected to be highly radiation tolerant because of the wide bandgap, high bond-strength and dynamic annealing features of the material. In addition, the absence of a gate oxide in junction field effect transistors (JFET) reduces accumulation of traps under ionizing radiation. However, these features may not offer immunity to single event effects, which is a unique damage mode in space applications. This study examines single event effect degradation in GaN JFETs as well as ohmic and Schottky diodes using pulsed laser exposure (lambda = 586 nm, full width at half maximum pulse width similar to 250 fs, 1 kHz frequency) for controllable characterization required to explore the fundamentals behind single event sensitivity. The single event transients occur on nanosecond time scales and exhibit maximum sensitivity in regions where n-type GaN is exposed and subjected to strong internal electric fields. These findings suggest that exposed n-type GaN layers represent critical vulnerability points requiring mitigation strategies for radiation-hardened GaN device design.

Metal halide perovskite materials are increasingly studied for use as room-temperature semiconductor radiation detectors due to the long carrier lifetimes, which enable thick, high-efficiency sensors. However, producing single crystal compounds like the widely researched CsPbBr3 can be cost-prohibitive and pose scalability problems, constraining their potential impact, particularly for field deployment applications. In this study, we show that polycrystalline materials with inherent grain boundaries can serve as counting and spectroscopic sensors. Polycrystalline CsPbBr3 compacts were developed by solid-state sintering of powder using field-assisted sintering technology (FAST). The pressure, temperature, hold time, and application of electric field were varied during compact processing and the resulting microstructures were compared to investigate the effects of these processing parameters on the densification process. X-ray diffraction (XRD) measurements confirmed that single-phase purity persisted throughout the synthesis process. Electrical characterization through dark current-voltage measurements showed a diode-like response due to asymmetric contacts, enabling low leakage current under reverse bias. Radiation detection capabilities were demonstrated by recording the detector's response to alpha-particle (Am-241) and gamma-ray (Cs-137) sources. These measurements were used to estimate the 15-100 mu m thick active volume of the detector based on pulse rise time information and spectral-shape evaluations. gamma-ray measurements demonstrated polycrystalline CsPbBr3 samples are capable of spectroscopic gamma-ray detection with 4.5% energy resolution at the Cs-137 662 keV peak. Electrical conditioning improved detector performance and provided insights into the overall stability of the polycrystalline CsPbBr3 material and its potential use in practical applications. The addition of polycrystalline materials to the existing body of radiation detectors enables the use of scalable fabrication techniques, potentially broadening the applications of radiation sensors.

We report the first-ever study on the radiation resilience of a back-end-of-line (BEOL) compatible W-doped Indium Oxide (IWO) ferroelectric field-effect transistor (FEFET) under neutron irradiation. The findings demonstrate remarkable resilience of both Hf0.5Zr0.5O2(HZO) ferroelectric capacitors (FECAPs) and IWO FEFETs to neutron irradiation. Subjected to neutron irradiation at fluences up to 10(15) n/cm(2), HZO FECAPs maintain stable remnant polarization (2P(r)) and coercive voltage (2V(c)) up to 10(11) cycles without any breakdown. The IWO FEFETs show robust switching performance and exhibit minimal degradation in memory window (MW) and read current window (CW). Importantly, the retention and endurance performance remain stable after neutron radiation exposure, without significant failure. Destiny simulations were performed to assess the impact of radiation on the system-level performance of an 8 MB 1T-1FEFET-based embedded RAM at the 32 nm node. The results showed negligible effects on read latency and only a minor 0.36% increase in dynamic read energy at a neutron fluence of 10(15) n/cm(2). The combination of high performance, non-volatility, and radiation hardness makes IWO FEFETs a promising candidate for high-density, persistent memory applications in radiation-rich environments.

The benign defect nature of iodide perovskites has gained strong momentum in understanding and application in perovskite devices; however, the understanding of defects in bromide perovskites remains elusive. Here we demonstrate that the biasing of lead bromide perovskite crystals, which has been broadly deemed as detrimental to device performance, can efficiently repair bulk point defects in them. The biasing results in a significant bromide-vacancy reduction, starting from the cathode side and progressing to the anode side across the whole crystal. The vacancies can diffuse back after several weeks of storage. By introducing bromine in crystal growth, we permanently reduce the bromide-vacancy concentration by ~1,000 times, enhancing charge transport and stability in formamidinium lead bromide crystals. The optimized formamidinium lead bromide detector exhibited a very high detection performance including an energy resolution of 0.7% under 137Cs 662-keV γ-rays measured under room-temperature, high-performance iodine K-edge X-ray detection at low agent concentrations and dramatically improved radiation hardness.

Inorganic scintillators are commonly used in various radiation detection applications due to their excellent energy resolution, reliable performance, relatively low cost, and high detection efficiency. However, many inorganic scintillators have high refractive indices and experience significant light losses at the collection surface caused by total internal reflection (TIR). This project employs optimized periodic nanostructures, known as photonic crystals (PHCs), to recover some of the light losses. A PHC layer creates an improved optical pathway between the scintillator and the photosensor for the trapped photons through constructive light interference. Enhancing the light extraction from an inorganic scintillator improves its energy resolution, time resolution, and the overall detection efficiency. In this work, the effects of an optimized PHC coupling with a LYSO scintillator are experimentally demonstrated. The PHC geometry is optimized through tailored simulations, manufactured with electron beam lithography, and characterized with radiation measurements to quantify improvements in light output and energy resolution. A 10 x 10 x 3 mm3 LYSO sample shows an improvement of 28% in light output and 13% in energy resolution with an optimized 2D block structure Si3N4 PHC structure. Future work will focus on expanding the experimental framework to other inorganic scintillators such as NaI and LaBr3, which are expected to have even greater light output improvements owing to their higher refractive index and total internal reflection.

Semiconductor devices contain defects and localized mechanical stress even in their pristine states, persisting after post-fabrication annealing. We hypothesize that these pre-existing conditions, with their lower threshold energy for defect proliferation and/or ionization, may serve as nuclei for radiation damage. To test this hypothesis, we adopted a two-pronged approach: (a) performing electron wind force (EWF) annealing preemptively on pristine Zener diodes to eliminate pre-existing defects before radiation exposure, and (b) applying EWF annealing restoratively on devices already damaged by radiation. The EWF process is non-thermal and can eliminate defects below 30 degrees C that persist through conventional thermal annealing. Both pristine and EWF-annealed pristine devices were exposed to 15 MeV protons with a fl uence of 10(14) cm(-2). Radiation damage increased the ideality factor from 1 to 2.33 in the pristine devices, while the preemptively EWF-annealed devices showed remarkable resilience, with an ideality factor of 1.5. Similar performance improvements were observed with restorative EWF annealing on radiation-damaged devices. This resilience and recovery in performance are further supported by Raman spectroscopy indicating enhanced crystallinity compared to the pristine condition. These fi ndings demonstrate the potential of EWF annealing as both a protective and restorative treatment for semiconductor devices in high-radiation environments.

Single event effects (SEE) in microelectronic devices are predominantly studied from the perspective of electrical charge generation and collection. This study introduces a multi-physics concept by investigating the impact of highly localized mechanical stress in electrically sensitive regions, such as the gate in a transistor. Our hypothesis is that reducing mechanical stress beneath the gate will decrease voltage transients caused by SEE by limiting charge generation and diffusion. To explore this electro-mechanical coupling in relation to SEE, we milled a microscale trench in the substrate beneath a transistor of the LM124 operational amplifier using a focused ion beam, thereby alleviating mechanical stress in the vicinity of the trench. We then perform pulsed laser SEE testing on the stress-relieved transistor and a control specimen without a micro-trench modification. Our experimental results demonstrate a significant decrease in single event transient peak amplitude and collected charge in the stress-relieved device compared to its pristine counterpart under identical pulsed laser conditions. These findings support our hypothesis and suggest that mitigating mechanical stress localizations could inform the design and fabrication of radiation-hardened electronics.

The β-polymorph gallium oxide (Ga2O3) is a promising material for next generation power electronics in extreme environments due to its ultra-wide bandgap with a high theoretical breakdown electric field. However, there is a gap between their predicted and observed reliability at high temperatures or radiation. Here, we investigated the forward bias induced degradation of the β-Ga2O3 Schottky barrier diode (SBD) during high temperature operation. Instead of using conventional post-degradation characterization, we adopted in situ high temperature operation of the β-Ga2O3 SBD inside a transmission electron microscope for real time visualization of the defect nucleation and evolution leading to degradation. The degradation mechanism involves the generation of vacancy clusters and nanoscale amorphized regions by the external and self-heating driven thermal field, which induces higher compressive strain on the β-Ga2O3 crystal. The nanoscale defects created lead to dislocations and stacking fault formation, mostly along the (200) lattice planes, under high temperature biasing conditions. The ultimate breakdown of the diode involves metal pool formation through the intermixing of the Ni/Au Schottky contact metals, which diffuse into the β-Ga2O3 drift layer under high electro-thermal stress. The accumulated defects at the anode metal pool/β-Ga2O3 interface cause highly nonuniform localized strain by void formation, which led to the final breakdown of the diode. The fundamental insights into the defect nucleation and propagation leading to failure may be useful to improve the reliability of β-Ga2O3 based devices for high temperature operation.

Using first principles calculations, 111 intrinsic stacking fault (ISF) energies in Group IVB, VB, and VIB high-entropy transition metal carbides are shown to be predictable from an optimized rule of mixtures based on the properties of the single metal carbide constituents present near the stacking fault. A composition-independent linear relationship is demonstrated between the ISF energies and the unstable stacking fault (USF) energies along the <112>111 gamma surface slip path. Treating the ISF and USF energies as analogous to the heat of reaction and transition state barrier in chemical reactions, this linear relationship represents a new application of the Evans-Polanyi-Semenov principle. Further, a full defect energy distribution can be obtained from the predicted ISF energies with only the composition as an input for the mixed early-transition metal carbides. Applying a model that balances the elastic repulsion between partial dislocations with the distribution of ISF energies, we show that Shockley partial edge dislocations should remain bound for all valence electron concentration values up to about 9.6, even when the average stacking fault energy is negative.

Effective thermal management is crucial in hypersonic flight (Mach > 5) due to extremely high aerodynamic heating located at leading edges, and both passive and active thermal protection systems (TPS) have been used to address this. Among passive TPS options are two-phase thermal management systems, such as heat pipes (HP) and vapor chambers (VC), which can realize a considerable reduction in steady-state leading edge temperature owing to their extremely high heat transfer capability. This leads to reduction in complexity and cost of TPS structure and material requirements. However, conventional HP and VC fabrication methods require multiple manufacturing and assembly steps, limiting their design space. Alternatively, utilizing additive manufacturing (AM) for fabrication can bypass conventional manufacturing limitations and enable structural members with intricate internal channels and topologically optimized shapes. AM can, therefore, unveil a larger design space for tailored leading edge concepts with an integrated passive TPS. This work demonstrates the design, fabrication and testing of a notional methanol-filled Inconel 718 VC with a conformal micro-pillar wick fabricated via laser-beam powder bed fusion AM. This serves as a proof of concept and establishes a foundation for design and fabrication of high-temperature additively manufactured sodium-filled leading edge VCs.

Two main components of power conversion equipment (PCE) are inductors and transformers. PCE have a plethora of applications, but their size, weight, and cost reduction are challenging problems that need precise engineering attention to be resolved, and can be specific for each application. Hence, increased power density, magnetic performance, and thermal margin during PCE operation is of critical importance to the ever-present need to make these components smaller and more efficient. This can occur by incorporating new advanced magnetic (AdvMag) materials in their designs that will improve the PCE performance compared to the currently used magnetic materials consisting primarily of laminated electrical steels. Our current work is dedicated to a comprehensive comparison of these different new advanced magnetics materials and how they can be used to improve both DC (low frequency) and AC performance of inductors and transformers, leading to much more efficient PCE devices. We analyze the effects of these emerging materials both theoretically and by using full-wave simulations. We conclude that amorphous alloys and new light-weight nanocrystalline magnetic materials can serve as suitable substitutes of steel in laminated transformer designs. In addition, ferrites can also improve inductor and transformer operation as they possess excellent thermal properties, reduced weight, and low loss. Our results will be useful to power engineers working on new and improved PCE devices with smaller size, lighter weight, higher power density, and increased operational frequency.