In an ionizing radiation environment, the formation of interface traps affects transistor performance, which may lead to device failure. This article reviews interface trap formation mechanisms in silicon-based devices. It explores interface trap types, electrical properties, and their impacts on devices’ performance. Finally, the main factors affecting the formation of interface traps are summarized. By reviewing these issues and exploring future research directions, guidance will be provided for the design of radiation-resistant devices to enhance their reliability in irradiated environments.
Uranium nitride (UN) is considered a promising candidate material for advanced nuclear fuels in Generation IV reactors due to its high thermal conductivity and excellent fission product retention capability. However, the surface corrosion behavior of UN in oxygen-containing environments severely limits its practical application. In this work, first-principles calculations based on density functional theory (DFT) were employed to systematically investigate the adsorption and dissociation behaviors of O2 molecules and O atoms on the UN(100), (110), and (111) surfaces. The electronic structure mechanisms underlying the adsorption were elucidated through analysis of surface work function, projected density of states (PDOS), Bader charge, and charge density difference. The calculated results show that O2 molecules undergo thermodynamically highly favorable dissociative chemisorption on all three UN surfaces at 0 K, with the O–O bond length stretched to 1.44–1.50 Å, characteristic of a peroxo-like (O22−) species, which is intermediate between the superoxide (O2−, ~1.33 Å) and complete dissociation. The most stable adsorption configurations on each surface are: (100)-H site (−4.05 eV), (110)-B(2) site (−4.81 eV), and (111)-H site (−5.03 eV), with the adsorption strength governed by the surface coordination environment. The adsorption energies of O atoms (−4.5 to −8.2 eV) are significantly higher than those of O2 molecules. The order of the most stable O atom adsorption sites is (110)-B(2) site (−8.22 eV) > (100)-H site (−6.97 eV) > (111)-T(U) site (−5.09 eV), which differs from that of O2, revealing the efficient O atom trapping effect of the groove structure on the (110) surface. Electronic structure analysis indicates that upon O atom adsorption, the work functions of the (100) and (110) surfaces increase by 0.62 eV and 0.39 eV, respectively, while that of the (111) surface decreases by 0.57 eV, suggesting that the (111) surface is more susceptible to further oxidation. In terms of bonding mechanisms, the interaction between O and U is primarily dominated by p–d hybridization between O-2p and U-6d orbitals. The U-5f orbital participates indirectly through f–d coupling with U-6d, while direct p–f hybridization is enhanced in the case of isolated O atom adsorption. This study provides an atomic-scale theoretical basis for understanding the initial oxidation mechanism of UN surfaces and offers important guidance for the surface protection design of UN-based nuclear fuels.
As a core fuel material for nuclear reactors, the segregation of non-metallic impurities and the hydrogen embrittlement effect at the grain boundaries of metallic uranium pose a serious threat to the long-term service safety of fuel elements.
Metallic uranium has important applications in nuclear fuels, nuclear materials, and related engineering fields because of its distinctive nuclear physical properties. However, its high chemical reactivity makes it susceptible to hydriding corrosion in hydrogen-containing environments. The substantial volumetric expansion associated with hydride formation, together with the resulting cracking and pulverization, severely compromises structural integrity and poses significant risks to long-term storage and safe service. Focusing on the role of grain boundaries in the hydriding corrosion of metallic uranium, this review summarizes current understanding of hydrogen ingress through the surface oxide layer, hydrogen segregation and migration at grain boundaries, and the regulation of these processes by elemental segregation. Defects and grain boundaries within the oxide layer can provide preferential pathways for hydrogen transport. In the metallic matrix, local structural distortion, excess free volume, and characteristic electronic structures at grain boundaries promote hydrogen trapping and accumulation, potentially facilitating hydride nucleation and intergranular damage by weakening interfacial cohesion. Metallic solutes affect the hydriding process primarily by modifying phase stability, hydrogen accumulation, and grain boundary cohesion, whereas the effects of non-metallic impurities depend on their states of occurrence, segregation tendencies, and co-segregation interactions with hydrogen. Grain boundary structure and local chemistry therefore jointly govern hydrogen ingress, accumulation, and damage evolution, making them central to understanding and regulating localized hydriding corrosion in metallic uranium.
1 October 2025 in Journal of Physics: Conference Series
A series of first-principles DFT+U calculations was performed to comprehensively explore the dissolution behaviour of atomic hydrogen (H), atomic oxygen (O), the hydrogen molecule (H 2 ), and the oxygen molecule (O 2 ) at plutonium dioxide (PuO 2 ) grain boundaries. The results indicate that both H and O atoms dissolve spontaneously into PuO 2 grain boundaries, which significantly trap these species. The grain-boundary volume expands upon dissolution, and the dissolution energy is governed by the interaction between the dissolved atoms and the boundary atoms; stronger bonding lowers the dissolution energy. When O atoms dissolve at the grain boundary, the resulting Pu–O bonds exhibit both covalent and ionic character. Moreover, H 2 and O 2 molecules also dissolve spontaneously at the grain boundary and tend to dissociate. Although some molecules remain intact, their bond lengths increase markedly. Density-of-states analysis reveals that, upon O 2 dissolution, the interaction between the O atoms and boundary O atoms manifests as a pronounced O-p peak between −7.5 and −5 eV. This study elucidates the dissolution patterns of atoms and molecules at PuO 2 grain boundaries and their bonding characteristics, providing key theoretical insights into the interfacial behaviour of PuO 2 -based materials.