This paper investigates the temperature-dependent effects of gamma-ray irradiation on β-Ga₂O₃ vertical Schottky barrier diodes (SBDs) under a 100 V reverse bias condition at a total dose of 1 Mrad(Si). As the irradiation dose increased, the radiation damage became more severe. The total ionizing dose (TID) degradation behavior and mechanisms were evaluated through DC, capacitance–voltage (C-V), and low-frequency noise (LFN) measurements by varying irradiation, and the test results indicated that TID effects introduced interface defects and altered the carrier concentration within the material. The impact of TID effects was more pronounced at lower temperatures compared to higher temperatures. Additionally, the annealing effect in the high-temperature experimental conditions ameliorated the growth of interface trap defects caused by irradiation. These results suggest that compared to low-temperature testing, the device exhibits higher TID tolerance after high-temperature exposure, providing valuable insights for in-depth radiation reliability studies on subsequent related devices.

Aiming at the significant needs of flexible DC converter valve applications in high-altitude areas, we investigate the effect of atmospheric neutrons on the failure rate of key core power devices in three kinds of converter valves, namely IGBTs, thyristors, and diodes. The safe working voltage boundary of the devices is obtained, and the failure rate caused by atmospheric neutrons in the real working environment of the power devices is calculated according to the results of the ground-accelerated irradiation test of atmospheric neutrons and the atmospheric neutron environment under the actual working conditions. The test results show that the failure rate of IGBTs, thyristors, and diodes caused by atmospheric neutrons is greatly affected by the blocking voltage, and the larger the blocking voltage is, the higher the failure rate of the device is. The research results can provide a basis for the design of the operating voltage of key core power devices of flexible DC converter valves and guide the evaluation of the failure rate and engineering design of the electronic system of DC ultra-high-voltage power transmission and transformation converter stations in the high-altitude environment of the Qinghai-Tibet Plateau.

GaN-based terahertz (THz) Schottky barrier diodes (SBDs) are critical components for achieving high-power performance in THz frequency multipliers. However, the space applications of GaN-based THz SBDs are significantly constrained due to insufficient research on the effects of space irradiation. This work investigates the effects of 450 MeV Kr swift heavy ion (SHI) irradiation on the electrical characteristics and induced defects in GaN-based THz SBDs. It was found that the high-frequency performance of GaN-based THz SBDs is highly sensitive to Kr SHI irradiation, which can be attributed to defects induced in the GaN epitaxial layer by the irradiation. Low-frequency noise analysis reveals trap states located at an energy level of approximately 0.62 eV below the conduction band. Moreover, the results from SRIM calculation and photoluminescence spectra confirmed the presence of irradiation-induced defects caused by Kr SHI irradiation.

Surface α-particle emissivity testing and spectral characterization of two leaded tin spheres (Sn_10%Pb_90%, Sn_63%Pb_37%) and one lead-free tin sphere (Sn_96.5%Ag_3.0%Cu_0.5%, SAC305) were carried out. The results show that Sn_10%Pb_90% Sn spheres have the highest α-particle emissivity; Sn_63%Pb_37% Sn spheres are the next highest, which is an order of magnitude lower than the α-particle emissivity of Sn_10%Pb_90% Sn spheres; and SAC305 Sn spheres have the lowest emissivity, which is reduced by about 55.6% compared to the emissivity of Sn_63%Pb_37% Sn spheres. All three types of tin spheres, after purification treatment, achieved the grade of ultra-low alpha particle emissivity (<0.002 α/(cm²·h)). The internal radionuclide traceability of the tin sphere, combined with the energy spectrum, reveals that the emission spectrum of the tin sphere exhibits an obvious “single peak” characteristic, with the peak energy in the interval of 5 MeV~5.5 MeV. Comparative analyses revealed that ²¹⁰Po is the main nuclide that produces alpha particles, and ²¹⁰Po originates from the decay of ²¹⁰Pb. Further Monte Carlo simulations show that α-particles with energies greater than 4.1 MeV in the measured energy spectrum all come from the contribution of radionuclides within 5 μm of the surface layer of the tin sphere, which accounts for 60% of the total radioactivity. Combining the experimental and simulation results, it is found that the internal radionuclides of the tin sphere are characterized by more surface layer and less internal layer. The above results are of great significance for the establishment of α-particle mitigation methods for tin spheres.