Electrically active defects in the phosphor-doped single-crystal silicon, induced by helium-ion irradiation under thermal annealing, have been investigated. Isothermal charge-sensitive deep-level transient spectroscop...Electrically active defects in the phosphor-doped single-crystal silicon, induced by helium-ion irradiation under thermal annealing, have been investigated. Isothermal charge-sensitive deep-level transient spectroscopy was employed to study the activation energy and capture cross-section of helium-induced defects in silicon samples. It was shown that the activation energy levels produced by helium-ion irradiation first increased with increasing annealing temperature, with the maximum value of the activation energy occurring at 873 K, and reduced with further increase of the annealing temperature. The energy levels of defects in the samples annealed at 873 and 1073 K are found to be located near the mid-forbidden energy gap level so that they can act as thermally stable carrier recombination centres.展开更多
针对热核聚变面向等离子体钨材料中氦泡形成、演变以及机理研究的需求,克服目前常用离子注入、电子扫描显微镜和透射电子显微镜等离线研究手段存在的不足,提出氦离子显微镜对钨中氦的上述行为原位实时在线研究方法.借助氦离子显微镜的...针对热核聚变面向等离子体钨材料中氦泡形成、演变以及机理研究的需求,克服目前常用离子注入、电子扫描显微镜和透射电子显微镜等离线研究手段存在的不足,提出氦离子显微镜对钨中氦的上述行为原位实时在线研究方法.借助氦离子显微镜的离子注入、显微成像和聚焦离子束纳米加工功能,它可以提供能量为0.5—35 ke V、束流密度可达10^(25) ions/(m^2·s)以上的氦离子束,在该设备上进行钨中氦的注入实验.同时在注入过程,实时在线监测钨中氦泡形成、演变过程以及钨材料表面形貌的变化,原位在线分析钨材料表面氦泡的大小、迁移合并以及其诱发的钨表面和近表面的微观损伤.实验结果表明:氦离子显微镜是研究钨中氦行为演变过程及其微观机理研究的新的研究手段和强有力的实验工具.展开更多
High-entropy alloys(HEAs)are potential alternative materials for accident-tolerant fuel cladding due to their excellent irradiation resistance and high-temperature corrosion resistance.In this work,two novel body-cent...High-entropy alloys(HEAs)are potential alternative materials for accident-tolerant fuel cladding due to their excellent irradiation resistance and high-temperature corrosion resistance.In this work,two novel body-centered cubic(bcc)structured Mo_(0.5)Nb Ti VCr_(0.25)and Mo_(0.5)Nb Ti V_(0.5)Zr_(0.25)HEAs were fabricated.Helium-ion irradiation was performed on the two HEAs to simulate neutron irradiation,and the crystal structure,hardness,and microstructure evolution were investigated.The crystal structure of the Mo_(0.5)NbTiVCr_(0.25)HEA remained stable at low fluences,while amorphization may occur at high fluences in the two HEAs.The irradiation hardening value of the Mo_(0.5)NbTiVCr_(0.25)was 0.77 GPa at fluences of 1×10^(17)ions/cm^(2)and 1.49 GPa at fluences of 5×10^(17)ions/cm^(2),while the hardening value of the Mo_(0.5)NbTiV_(0.5)Zr_(0.25)was 1.36 GPa at ion fluences of 5×10^(17)ions/cm^(2).In comparison with most of the conventional alloys,the two HEAs showed slight irradiation hardening.The helium bubbles and dislocation loops with small size were observed in the two HEAs after irradiation.This is the first time to report the formation of a dislocation loop in bcc-structure HEAs after irradiation.However,voids and precipitates were not observed in the two HEAs which could be ascribed to the high lattice distortion and compositional complexity of HEAs.This research revealed that the two HEAs show outstanding irradiation resistance,which may be promising accident-tolerant fuel cladding materials.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No 10575124)
文摘Electrically active defects in the phosphor-doped single-crystal silicon, induced by helium-ion irradiation under thermal annealing, have been investigated. Isothermal charge-sensitive deep-level transient spectroscopy was employed to study the activation energy and capture cross-section of helium-induced defects in silicon samples. It was shown that the activation energy levels produced by helium-ion irradiation first increased with increasing annealing temperature, with the maximum value of the activation energy occurring at 873 K, and reduced with further increase of the annealing temperature. The energy levels of defects in the samples annealed at 873 and 1073 K are found to be located near the mid-forbidden energy gap level so that they can act as thermally stable carrier recombination centres.
文摘针对热核聚变面向等离子体钨材料中氦泡形成、演变以及机理研究的需求,克服目前常用离子注入、电子扫描显微镜和透射电子显微镜等离线研究手段存在的不足,提出氦离子显微镜对钨中氦的上述行为原位实时在线研究方法.借助氦离子显微镜的离子注入、显微成像和聚焦离子束纳米加工功能,它可以提供能量为0.5—35 ke V、束流密度可达10^(25) ions/(m^2·s)以上的氦离子束,在该设备上进行钨中氦的注入实验.同时在注入过程,实时在线监测钨中氦泡形成、演变过程以及钨材料表面形貌的变化,原位在线分析钨材料表面氦泡的大小、迁移合并以及其诱发的钨表面和近表面的微观损伤.实验结果表明:氦离子显微镜是研究钨中氦行为演变过程及其微观机理研究的新的研究手段和强有力的实验工具.
基金supported by the Key Program of the Chinese Academy of Sciences(No.ZDRW-CN-2017-1)。
文摘High-entropy alloys(HEAs)are potential alternative materials for accident-tolerant fuel cladding due to their excellent irradiation resistance and high-temperature corrosion resistance.In this work,two novel body-centered cubic(bcc)structured Mo_(0.5)Nb Ti VCr_(0.25)and Mo_(0.5)Nb Ti V_(0.5)Zr_(0.25)HEAs were fabricated.Helium-ion irradiation was performed on the two HEAs to simulate neutron irradiation,and the crystal structure,hardness,and microstructure evolution were investigated.The crystal structure of the Mo_(0.5)NbTiVCr_(0.25)HEA remained stable at low fluences,while amorphization may occur at high fluences in the two HEAs.The irradiation hardening value of the Mo_(0.5)NbTiVCr_(0.25)was 0.77 GPa at fluences of 1×10^(17)ions/cm^(2)and 1.49 GPa at fluences of 5×10^(17)ions/cm^(2),while the hardening value of the Mo_(0.5)NbTiV_(0.5)Zr_(0.25)was 1.36 GPa at ion fluences of 5×10^(17)ions/cm^(2).In comparison with most of the conventional alloys,the two HEAs showed slight irradiation hardening.The helium bubbles and dislocation loops with small size were observed in the two HEAs after irradiation.This is the first time to report the formation of a dislocation loop in bcc-structure HEAs after irradiation.However,voids and precipitates were not observed in the two HEAs which could be ascribed to the high lattice distortion and compositional complexity of HEAs.This research revealed that the two HEAs show outstanding irradiation resistance,which may be promising accident-tolerant fuel cladding materials.
