Purpose SiC MOSFETs are widely used in aerospace and power electronics owing to their superior electrical properties, yet they suffer from combined threats of space radiation and thermo-electrical stress fatigue. This study aims to explore the influence of electron irradiation on the power cycling lifetime of SiC MOSFETs and reveal the corresponding failure mechanisms, offering a theoretical basis for the reliability evaluation of SiC MOSFETs in space radiation environments. Design/methodology/approach Experiments were conducted using 10 MeV electron irradiation at doses of 3 Mrad, 5 Mrad and 10 Mrad(Si), followed by forward-mode power cycling tests. Electrical parameters including threshold voltage and on-resistance were monitored periodically. Optical microscopy was adopted to characterize bond wire and solder layer damage. Electro-thermal-mechanical coupling simulation and Geant4 simulation were applied to analyze the internal stress distribution and energy deposition, clarifying the failure evolution process. Findings Electron irradiation induces negative drift of threshold voltage and reduction of on-resistance via gate oxide charge trapping. During power cycling, threshold voltage shifts positively and on-resistance rises significantly with cycling count, and higher irradiation dose aggravates the drift amplitude. Electron irradiation drastically shortens the power cycling lifetime, which is reduced by 60% at 10 Mrad compared with unirradiated devices. Irradiation creates lattice defects in the solder layer, forming voids under cyclic thermal stress, which intensifies stress concentration at bond wire-chip joints and accelerates bond wire lift-off as the final failure mode. Originality/value This study systematically reveals the synergistic degradation mechanism of electron irradiation and power cycling on SiC MOSFETs, distinguishing chip-level electrical parameter degradation and package-level mechanical failure. It provides key data and mechanistic support for the lifetime prediction and reliability optimization of SiC power devices in space applications.

PurposeGaN HEMT devices are often exposed to harsh environments (such as irradiation and temperature fluctuations) in practical applications, which can significantly degrade their reliability. The purpose of this study is to investigate the degradation of electrical performance and failure mechanisms of GaN HEMT devices under the combined effects of electron irradiation and thermal cycling, providing valuable reference information for the reliability assessment of GaN HEMT devices.Design/methodology/approachBy comparing with the individual thermal cycling experiments, this study investigates the effects of the combined electron irradiation and thermal cycling on device failure. An optical microscope was used to observe the liftoff phenomenon of the bond pads, and finite element analysis was used to simulate the device's behavior. In addition, G4 simulation software was used to analyze the accumulation of residual stress in the bond pad region after irradiation. These findings provide crucial insights into the failure mechanisms of the device under the combined effects of electron irradiation and thermal cycling.FindingsStudies have shown that the electron irradiation on the device surface generated localized heat after the introduction of irradiation, which further led to residual stresses in the metal pad region. Under the combined effect of electron irradiation and thermal cycle, the device showed chip-level degradation in the first 750 thermal cycles, and the on-resistance increased by 20%. With the further extension of the aging time, the device entered the package-level degradation stage, and the on-resistance increases significantly, reaching 106 %.Originality/valueThis study provides valuable insights into the long-term reliability of P-GaN gate HEMTs for simulated space applications. By considering electron irradiation and thermal cycling as combined stress factors, the degradation process of the chip was examined, with initial degradation occurring at the chip level, followed by packaging-level degradation.

In recent years, (3-Ga2O3 has demonstrated significant application potential in radiation environments such as aerospace due to its excellent physical properties. However, its damage behavior under high-energy proton irradiation requires further investigation. This study establishes structural models containing seven vacancy defects and systematically calculates defect formation energies and stabilities using density functional theory. Moreover, we analyze the effects of these defects on electronic structure, carrier mobility, and lattice thermal conductivity. The results indicate that high-energy proton irradiation primarily induces oxygen and galliumoxygen complex vacancies. Among these, oxygen vacancies significantly reduce electron mobility, while gallium and gallium-oxygen complex vacancies decrease the bandgap. Polar optical phonon scattering is the dominant mechanism limiting carrier mobility of (3-Ga2O3. All defects reduce thermal conductivity, with gallium and gallium-oxygen complex vacancies causing a more significant reduction. This study reveals the intrinsic connection between proton irradiation-induced defect types and the degradation of (3-Ga2O3 material properties, providing theoretical foundations for radiation damage assessment of (3-Ga2O3 based devices.

This work investigates the reliability of enhanced dual-trench SiC MOSFETs in space radiation environments through a combined experimental and simulation approach involving proton and heavy ion irradiation. Experiments utilizing 80-MeV protons and 210-MeV Ge ions were conducted to systematically analyze the degradation of the devices’ electrical characteristics. The results revealed a decrease in the threshold voltage for single-event burnout (SEB) and a shorter burnout time. By employing the combined Geant4 and TCAD simulations, the study elucidates that ionization damage within the gate oxide layer exacerbates the electric field redistribution and promotes the turn-on of the parasitic bipolar junction transistor (BJT), resulting in the increasing sensitivity to SEB. These findings provide a theoretical and experimental foundation for the application and radiation-hardened design of SiC power devices in extreme radiation environments.

This study investigates the influence of high-temperature gate bias (HTGB) on the sensitivity to total ionizing dose (TID) effect in p-GaN gate HEMTs. It is found that gamma-irradiation induces negative shift of threshold voltages, increased transconductance, and higher drain current, which are much more pronounced in devices subjected to HTGB than in those that were not. The results show that HTGB significantly enhances the device's sensitivity to TID effects. Furthermore, theoretical analysis was performed and the underlying mechanism can be attributed to the HTGB-induced Schottky junction damage and the increase of electric field induced by the net negative charge in AlGaN barrier layer.

Compared to radiation-hardened solid-state memory designed for space missions, commercial NAND solid-state drives (SSDs) offer significant advantages in cost efficiency and storage density but exhibit high susceptibility to single event effects (SEEs) in space radiation environments. While numerous studies have observed single event functional interrupt (SEFI) phenomena in these devices, the underlying mechanisms remain unclear. This study innovatively employs a TCAD-SPICE co-simulation approach to systematically elucidate SEFI mechanisms across device physics and circuit logic levels. Key findings reveal that transient current surges induce abnormal reference voltages in row/column decoders, causing read signal inversion and consequent burst bit-flip errors. Proton irradiation triggers output failure of D flip-flops in NAND flash arrays due to transient currents, disrupting command transmission. Single event upsets (SEUs) in SRAM cells or command processing units of SSD controllers interrupt read/write operations. The research provides some complete mechanistic analyses from particle energy deposition to system-level failure, establishing a comprehensive theoretical framework for understanding the radiation effects in flash memory devices.

Neutron irradiation-induced defects significantly compromise the service safety of materials used in nuclear facilities. This study proposes a multiscale simulation framework that quantitatively links irradiation-induced defect generation to the elastic property degradation of composite materials. Spatially resolved defect concentrations are first obtained through Monte Carlo neutron transport simulations and mapped onto representative volume element (RVE) as stochastically distributed equivalent micro-voids. Numerical homogenization of the defective RVE yields the full elastic stiffness matrix, and macroscopic elastic modulus is further extracted through tensile simulations. Validation using neutron-irradiated T700/AG80 composites shows good agreement between predictions and experiments, with errors below 5.1%. The results also reveal pronounced anisotropic damage: transverse and shear stiffness degrade markedly due to resin damage, whereas the fiber-direction stiffness remains relatively stable. The proposed framework provides a practical tool for evaluating irradiation effects in various composite systems.

The Jupiter mission has been recognized as an important piece of deep-space exploration. Traditional shielding materials struggle to meet the radiation protection requirements for Jupiter exploration; therefore, the development of lightweight, high-performance shielding materials is essential to ensuring the long-term safe operation of the Jupiter probe. In this study, low-density polyethylene (PE), which possesses excellent shielding performance, is selected as the matrix material, and the effects of composition ratio, doping concentration and particle size of three dopants (C, W, and B4C) on the comprehensive proton and electron shielding performances of PE composites are investigated. The study has found that the shielding performance of PE composite is optimal when the composition ratio of C, W, and B4C is 4–4–1. Moreover, the PE with the doping concentration of 15 ± 5 wt

This study investigates the effect of temperature on leakage current degradation in p-GaN gate high electron mobility transistors (HEMTs) under heavy ion irradiation. Experimental results show that Kr ion irradiation at room temperature significantly increases drain leakage current, primarily along the source-drain path. The device undergoes electrical degradation, with a 5.2% positive shift of V TH and a 26.5% reduction of output current. At higher temperatures (350 K–400 K), the distribution of leakage path remains in different regions of gate-to-drain. Hole accumulation beneath the gate increases the electric field in the p-GaN layer, raising the risk of single-event gate rupture and single-event burnout. Utilizing TCAD simulation, the temperature effect on the leakage path distribution can be attributed to the temperature-related electric field, lattice temperature, and carrier thermal excitation and tunneling. These findings provide theoretical insights for understanding the single-event leakage current characteristics of p-GaN gate HEMTs in space radiation environments.

In this study, the synergistic irradiation effects on Cascode GaN high electron mobility transistors (HEMTs) subjected to 80 MeV proton and Ge ion irradiation with a linear energy transfer (LET) of 37 MeV cm(2).mg(-1) were investigated. The experimental results demonstrated that such synergistic irradiation leads to a 10 % reduction in the single-event burnout (SEB) threshold voltage. Geant4 and TCAD simulations revealed that high-energy proton irradiation induces a significant number of displacement defects within the GaN HEMT structure. During subsequent Ge ion irradiation, these pre-existing displacement defects near the gate region act as electron traps, forming negatively charged defect centers. This results in an enhanced electric field intensity within the channel, facilitating avalanche multiplication of carriers. Consequently, a large number of holes accumulate beneath the gate, lowering the electron barrier in the channel. This condition promotes electron injection into leakage paths via the tunneling effect, thereby forming a burnout channel between the gate-drain region of the depleted GaN HEMT and the source of the Si MOSFET. As a result, the Cascode GaN HEMT device becomes susceptible to SEB at a lower operating voltage. These findings provide important theoretical insights into SEB behavior and contribute to the reliability assessment of Cascode GaN HEMT devices in radiation environments.

This study investigates the effect of different gate biases on the leakage current of p-type GaN high electron mobility transistors (HEMTs) under heavy ion irradiation. Utilizing Ta ion irradiation, the leakage degradation at the gate bias $V_{\mathrm {gs}}$ range of 0 to -5 V was studied. The most severe degradation was observed at approximately $V_{\mathrm {gs}}=-3$ V. Electrical measurements revealed a 20% positive shift in threshold voltage (at $V_{\mathrm {gs}}=-3$ V), a two times increase in on-resistance, a reduction in Schottky barrier height, and a significant shift in the ideality factor after heavy ion exposure. Technology computer-aided design (TCAD) simulations indicated that increasing the magnitude of negative gate bias enhanced the internal electric field strength, while the lattice temperature exhibited a decreasing trend. The analysis suggests that under heavy ion irradiation, leakage current at different gate biases is primarily attributed to micro-burn channels formed via thermal excitation and carrier tunneling, with their likelihood governed by the internal electric field and lattice temperature. Under the intermediate gate bias, the electric field strength and lattice temperature inside the device were both higher, resulting in more micro-burned channels and a significantly higher leakage rate than other bias conditions. These findings can provide an important theoretical basis for the single event leakage degradation characteristics during the potential application of p-GaN HEMT devices in radiation environment.

This study investigates the influence of neutron irradiation on the heavy-ion-induced leakage degradation in p-GaN gate high electron mobility transistors (HEMTs). Neutron irradiation experiments at different energies were conducted, revealing a positive shift in the threshold voltage (VTH) and a reduction in the output saturation drain current (IDS). Subsequent Ta-ion irradiation experiments were conducted to investigate the leakage current degradation during the irradiation process. We observed that devices pre-irradiated with neutrons exhibit weaker leakage degradation during heavy-ion irradiation compared to unirradiated devices, suggesting a suppression effect of neutron irradiation on heavy-ion-induced leakage degradation. Simulations using technology computer-aided design (TCAD) and GEometry ANd Tracking 4 (Geant4) were performed to elucidate the underlying mechanisms. The results revealed that neutron irradiation introduces acceptor-like traps in GaN devices, reducing the electron concentration generated during heavy-ion irradiation, thereby suppressing drain leakage current (ID). Furthermore, the lattice temperature and impact generation rate during irradiation were observed to decrease, hindering the formation of leakage paths and mitigating damage in the drain region. This study represents the first observation of neutron irradiation suppressing heavy-ion-induced leakage degradation in GaN devices, thus providing a theoretical foundation for improving the radiation hardness of GaN HEMTs against leakage degradation.

Recently, transition metal dichalcogenide (TMDCs) monolayers have garnered significant interest due to their unique physical properties. Hence, this study investigates the thermal and electrical properties of T '-WS2 monolayers doping with transition metal atoms (Mo and Cr) through first-principles calculations. The research results show that the lattice thermal conductivities of the four doped monolayers (Mo1-WS2, Mo2-WS2, Cr1-WS2, and Cr2-WS2) at 300 K are significantly reduced by 55.49%-58.67% compared to the pristine T '-WS2 monolayer. Metal atom doping will affect the thermal conductivity through a synergistic effect in phonon heat capacity, phonon lifetime, and phonon group velocity. Moreover, doping Cr and Mo atoms can transform the pristine T '-WS2 monolayer into a direct bandgap semiconductor, and Cr atom doping exhibits a stronger electronic modulation capability than Mo atom doping. The total density of states near the Fermi level in the Cr doped system is significantly enhanced, increasing by orders of magnitude compared to the T '-WS2 monolayer. Our findings display the impact of Mo and Cr doping on the phonon heat transport and electronic properties of the T '-WS2 monolayer, which would provide key data support for TMDCs based electronic devices.

In recent years, although two-dimensional (2D) Janus transition metal dichalcogenide (TMDC) monolayers have gradually been applied to electronic devices owing to their distinctive physical properties, their phonon thermal transport properties remain unclear. Here, we systematically explore the phonon thermal properties of six types of 2D Janus TMDC monolayers MXY (M = Mo, S; X, Y = S, Se, Te) by performing the first-principles calculations. After considering the size effect, the phononic thermal conductivities (kph) of these monolayers have size-dependency up to more than 10–100 μm. Moreover, the atomic mass dependence of the kph is observed, and the Janus TMDC monolayers with a Te element have smaller kph. Furthermore, in monolayers with small system size, phonon–boundary scattering has a greater impact on kph, leading to a weakened temperature dependence of kph. Finally, based on the phonon behaviors, we can prove that MSSe monolayers have the largest kph owing to their higher phonon heat capacity, group velocity, and lifetime, whereas the competition between the three parameters leads to the kph being close to each other for MSTe and MSeTe monolayers. Our research offers a necessary study of phonon thermal transport abilities in 2D Janus TMDC monolayers.

This study investigates the damage mechanisms of triple-junction GaAs solar cells under 10MeV high-energy electron irradiation, addressing limitations of previous low-energy (e.g., 1MeV) electron studies. Experimental results show that with increasing electron fluence, the electrical performance degrades significantly, with open-circuit voltage decreasing more markedly than short-circuit current. Combined CASINO and TCAD simulations reveal higher non-ionizing energy deposition and more severe displacement damage in the GaAs middle subcell. Analysis of recombination rates and energy band structure indicates an evolution of defect types from simple point defects to complex clusters under high-energy irradiation, leading to increase in recombination rate and severe band distortion. These findings provide deeper insights into the damage mechanism of high-energy electrons and lay a theoretical foundation for radiation-hardened design and lifetime assessment of space solar cells.

In recent years, the role of four-phonon (4ph) scattering in thermal transport properties has been gradually revealed. However, the underlying scattering mechanisms of the bulk beta-Ga2O3 and monolayer Ga2O3 remain unclear. Hence, we evaluate the effect of 4ph scattering on the thermal transport properties of the bulk beta-Ga2O3 and monolayer Ga2O3 by utilizing first-principles calculations. It has been observed that the Young's modulus and lattice thermal conductivity (kappa) of the bulk beta-Ga2O3 are anisotropic, while the values of the monolayer Ga2O3 are isotropic. The kappa of the bulk beta-Ga2O3 along the three directions ([100], [010], and [001]) and monolayer Ga2O3 after adding 4ph scattering are decreased by 9.23%, 11.52%, 13.89%, and 29.24% at 300 K, respectively. Moreover, the effect of four-phonon scattering is more pronounced at the high temperature. Afterwards, based on the phonon behaviors, we can prove that the addition of 4ph scattering can increase the phonon scattering rate, decrease the phonon mean free path, and increase the phase space, which results in lower thermal conductivity. The findings can contribute to a better understanding of high-order phonon scattering mechanisms of the Ga2O3 materials.

With excellent optical properties and high carrier mobility,perovskite materials have become highly competitive materials in the field of space solar cells.However,space particle irradiation can change the structure and optical properties of materials,leading to a rapid degradation of device performance.In or-der to investigate the influence of electron irradiation on the structure and optical properties of CsPbBr3 nano-crystals,we conducted electron irradiation experiments on CsPbBr3 materials,characterized the microscopic morphology of CsPbBr3 nanocrystals by high-resolution transmission electron microscopy.Moreover,we in-vestigated the variation trend of crystal structure by X-ray diffraction analysis and X-ray photoelectron spec-troscopy analysis.The results revealed electron irradiation caused the CsPbBr3 nanocrystals to become rough and significantly decrease in size.The nanocrystal became compact and formed nanocluster under high-dose electron irradiation.Furthermore,the optical properties of CsPbBr3 materials were characterized using steady-state UV-Vis absorption spectra and photoluminescence spectra.The analysis of lattice expansion-in-duced bandgap changes after irradiation was performed using first principles calculations.It is demonstrated that electron irradiation deepened the color of nanocrystals and affected the light transmittance of CsPbBr3 nanocrystalline,thereby enhancing the optical absorption performance of the samples.However,electron ir-radiation also led to the decomposition of CsPbBr3 nanocrystals,resulting in a significant reduction in lumin-escence intensity of the CsPbBr3 by 53.7%-78.6%after high-dose irradiation.These findings provide valu-able data support for the study of spatial radiation damage mechanisms and the application of perovskite nanocrystals.

Recently, two-dimensional (2D) triphosphides have attracted much attention in the thermoelectric field due to their semiconductor properties and excellent electronic transport properties. In our study, the performances of AlP3, Al0.5Ga0.5P3, and Al0.5In0.5P3 doped monolayers in the thermoelectric transport are studied. First, the dynamic structural stabilities of the three monolayers are verified through phonon dispersion curves. Moreover, all monolayers are indirect band-gap semiconductors, which can be used as thermoelectric materials. The results show that larger electronic relaxation time and carrier mobilities of doped monolayers lead to larger electronic transport parameters and higher dimensionless thermoelectric figure-of-merit (ZT). It is found that after doping via Ga and In, the thermoelectric performances of AlP3 are increased by 1.31-1.79 times. Our findings show that AlP3 and its doped monolayers hold significant promise as thermoelectric materials within the temperature span of 300-700 K and the doping mechanism could significantly improve the thermoelectric properties of 2D structures.

Recently, the two-dimensional semiconductor C 3 B monolayer has attracted much attention owing to its excellent physical, optical, and electronic properties. In this work, the origin of electron -phonon interaction (EPI) on the thermal properties of C 3 B by n -type and p -type doping is systematically investigated via first -principles calculations to provide fundamental knowledge for the thermal management the C 3 B-based electronic devices. The carrier concentrations for the largest reduction of the lattice thermal conductivity ( kappa ) appear at 4 x 10 14 cm -2 for n -type and 9 x 10 14 cm -2 for p -type, which is closely related to the electron density of states (DOS). The boron (B) atoms break the structural symmetry and induce mass disorder scattering, which renders C 3 B more prone to the influence of EPI. Moreover, the electronic band structure in the C 3 B monolayer exhibits multivalley characteristics, which leads to an intervalley scattering. It is worth noting that the anisotropy in the C 3 B monolayer can be significantly enhanced by EPI. Additionally, an abnormal phenomenon of strong electron -phonon scattering but low electron -phonon coupling strength is found in C 3 B monolayer, which indicates that large electronphonon coupling strength is sufficient but not necessary for strong electron -phonon scattering.

Nanofluids are considered as excellent coolants to optimize thermal management of electronic devices, where the nanoparticle morphology and the addition of surfactants can affect the thermal transport performance of nanofluids. Due to the limitations of high economic and computational cost in previous experimental and numerical simulation methods, the design of nanofluids urges for more efficient approaches. In this work, a novel machine learning framework coupled with molecular dynamics methods was proposed to model the multi-component mixing nanofluidic systems and explore the deep heat transfer mechanisms. Multi-input attribute point cloud dataset, dual channel sampling network and multi-nanoscale optimization scheme were used to improve the prediction performance of machine learning. The computational cost of the machine learning method is shortened by 36000 times compared with simulation methods. Moreover, our work can achieve up to 90% prediction accuracy for surfactant adsorption properties. Furthermore, algorithm optimization strategy can improve the prediction accuracy of nanofluidic heat transfer performance by 40%. The proposed framework has the potential to shorten the development cycle of nanofluidic design.