A Cemented Carbide material was implanted with dual nitrogen plus tantalum ions at temperatures of 100℃ and 400℃ and a dose of 8× 10^17 ions cm^-2. The thickness of the implanted layers increased by about an or...A Cemented Carbide material was implanted with dual nitrogen plus tantalum ions at temperatures of 100℃ and 400℃ and a dose of 8× 10^17 ions cm^-2. The thickness of the implanted layers increased by about an order of magnitude when the temperature was elevated from 100℃ to 400℃. Higher surface hardness was also obtained in the high temperature implantation. X-ray diffraction showed the presence of nitrides of tantalum and tungsten in the implanted surface.展开更多
Hard alloy were implanted with a dudl-ion of nitrogen and tatalum at temperature of 100℃ and 400℃ at a dose of 8×1017 ions cm-2 .Auger electron spectroscopy (AES) was used to determine the nitrogen and tantalum...Hard alloy were implanted with a dudl-ion of nitrogen and tatalum at temperature of 100℃ and 400℃ at a dose of 8×1017 ions cm-2 .Auger electron spectroscopy (AES) was used to determine the nitrogen and tantalum concentration profiles. Microhardness measurements were performed to evaluate the improvements in surface property. The thickness of implanted layers increased by about an order of magnitude when the temperature was elevated from 100℃ to 400 ℃. A higher surface hardness was also obtained in the higher temperature implantation. Scanning electron microscopy (SEM) image showed distinct microstructural changes, and X-ray diffiaction (XRD) analysis showed the presence of nitrides of tantalum and tungsten on the surface implanted.展开更多
Metal nitrides are widely studied due to their outstanding physical properties, including high hardness,high thermal and chemical stability, low electrical resistivity etc. Generally, metal nitrides can be obtained fr...Metal nitrides are widely studied due to their outstanding physical properties, including high hardness,high thermal and chemical stability, low electrical resistivity etc. Generally, metal nitrides can be obtained from the direct reaction of metal and ammonia/nitrogen. However, some of the metal nitrides,such as Ta_3N_5, cannot be synthesized by direct nitridation of metals. To achieve Ta_3N_5, high-oxidationstate Ta precursors like Ta_2O_5, NaTaO_3, TaS_3, K_6Ta_(10.8)O_(30), Ta(N(CH_3)_2)_5 and TaCl_5 have to be employed,which is a time-consuming and laborious process with the possibility of introducing undesirable impurities. Here taking Ta_3N_5 as an example, a facile carbonate-assisted one-step nitridation method is proposed, which enables the direct synthesis of high-oxidation-state metal nitride films from metal precursors under ammonia flow. The mechanism of the nitridation process has been studied, which carbon dioxide released from carbonates decomposition reacts with metallic Ta and assists the one-step conversion of metallic Ta to Ta_3N_5. The as-prepared Ta_3N_5 film, after modified with NiFe layered double hydroxide, exhibits promising water splitting performance and stability. This method avoids the preoxidation process of metal precursors in high-oxidation-state metal nitride synthesis, and may facilitate the direct fabrication of other important metal nitrides besides Ta_3N_5.展开更多
Ta3N5 is regarded as a promising photocatalyst for solar water splitting because of its excellent visible light absorption characteristics and simple composition.Conventional Ta3N5 photocatalysts prepared from oxide p...Ta3N5 is regarded as a promising photocatalyst for solar water splitting because of its excellent visible light absorption characteristics and simple composition.Conventional Ta3N5 photocatalysts prepared from oxide precursors typically comprise aggregated polycrystalline particles with defects and grain boundaries that reduce the water oxidation activity of the material.In the present work,well-dispersed Ta3N5 nanoparticulate single crystals were synthesized via a mild nitridation process using pure Ta metal nanopowder or Ta nanopowder mixed with NaCl.The resulting high-quality Ta3N5 nanoparticles,after loading with an oxygen evolution cocatalyst,exhibited impressively high photocatalytic performance during O_(2)evolution from a sacrificial AgNO3 solution,with an apparent quantum yield of 9.4%at 420 nm.Our findings suggest a new approach to the facile fabrication of nanostructured single-crystal photocatalysts for efficient solar water splitting,based on the use of metal nanopowders.展开更多
超大规模集成电路Cu互连中的核心技术之一是制备性能优异的扩散阻挡层。本文采用直流磁控反应溅射在N2/Ar气氛中制备了不同组分比的Ta-N薄膜,并原位制备了Cu/Ta-N/基底复合结构,对部分样品在N2保护下进行了快速热处理(RTA),采用台阶仪...超大规模集成电路Cu互连中的核心技术之一是制备性能优异的扩散阻挡层。本文采用直流磁控反应溅射在N2/Ar气氛中制备了不同组分比的Ta-N薄膜,并原位制备了Cu/Ta-N/基底复合结构,对部分样品在N2保护下进行了快速热处理(RTA),采用台阶仪、四探针测试仪、原子力显微镜(AFM)、扫描电镜、X射线衍射(XRD)对薄膜形貌结构进行了表征。结果表明,随着N2流量比的增加,薄膜沉积速率下降,表面趋于平滑,Ta-N薄膜热稳定性能及阻挡性能随之提高,而电阻率则上升。氮流量比为0.3制备的厚度为100nm的Ta-N薄膜经600℃/5m in RTA后,仍可保持对Cu的有效阻挡;在更高温度下退火,Cu将穿过阻挡层与Si发生反应,导致阻挡层失效。展开更多
文摘A Cemented Carbide material was implanted with dual nitrogen plus tantalum ions at temperatures of 100℃ and 400℃ and a dose of 8× 10^17 ions cm^-2. The thickness of the implanted layers increased by about an order of magnitude when the temperature was elevated from 100℃ to 400℃. Higher surface hardness was also obtained in the high temperature implantation. X-ray diffraction showed the presence of nitrides of tantalum and tungsten in the implanted surface.
文摘Hard alloy were implanted with a dudl-ion of nitrogen and tatalum at temperature of 100℃ and 400℃ at a dose of 8×1017 ions cm-2 .Auger electron spectroscopy (AES) was used to determine the nitrogen and tantalum concentration profiles. Microhardness measurements were performed to evaluate the improvements in surface property. The thickness of implanted layers increased by about an order of magnitude when the temperature was elevated from 100℃ to 400 ℃. A higher surface hardness was also obtained in the higher temperature implantation. Scanning electron microscopy (SEM) image showed distinct microstructural changes, and X-ray diffiaction (XRD) analysis showed the presence of nitrides of tantalum and tungsten on the surface implanted.
基金supported by the National Natural Science Foundation of China (U1663228 and 21473090)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘Metal nitrides are widely studied due to their outstanding physical properties, including high hardness,high thermal and chemical stability, low electrical resistivity etc. Generally, metal nitrides can be obtained from the direct reaction of metal and ammonia/nitrogen. However, some of the metal nitrides,such as Ta_3N_5, cannot be synthesized by direct nitridation of metals. To achieve Ta_3N_5, high-oxidationstate Ta precursors like Ta_2O_5, NaTaO_3, TaS_3, K_6Ta_(10.8)O_(30), Ta(N(CH_3)_2)_5 and TaCl_5 have to be employed,which is a time-consuming and laborious process with the possibility of introducing undesirable impurities. Here taking Ta_3N_5 as an example, a facile carbonate-assisted one-step nitridation method is proposed, which enables the direct synthesis of high-oxidation-state metal nitride films from metal precursors under ammonia flow. The mechanism of the nitridation process has been studied, which carbon dioxide released from carbonates decomposition reacts with metallic Ta and assists the one-step conversion of metallic Ta to Ta_3N_5. The as-prepared Ta_3N_5 film, after modified with NiFe layered double hydroxide, exhibits promising water splitting performance and stability. This method avoids the preoxidation process of metal precursors in high-oxidation-state metal nitride synthesis, and may facilitate the direct fabrication of other important metal nitrides besides Ta_3N_5.
基金supported by the Artificial Photosynthesis Project of the New Energy and Industrial Technology Development Organization(NEDO).Part of this work was conducted at the Advanced Characterization Nanotechnology Platform of the University of Tokyo,supported by the“Nanotechnology Platform”of the Ministry of Education,Culture,Sports,Science and Technology(MEXT),Japan(No.JPMXP09A-19-UT-0023).
文摘Ta3N5 is regarded as a promising photocatalyst for solar water splitting because of its excellent visible light absorption characteristics and simple composition.Conventional Ta3N5 photocatalysts prepared from oxide precursors typically comprise aggregated polycrystalline particles with defects and grain boundaries that reduce the water oxidation activity of the material.In the present work,well-dispersed Ta3N5 nanoparticulate single crystals were synthesized via a mild nitridation process using pure Ta metal nanopowder or Ta nanopowder mixed with NaCl.The resulting high-quality Ta3N5 nanoparticles,after loading with an oxygen evolution cocatalyst,exhibited impressively high photocatalytic performance during O_(2)evolution from a sacrificial AgNO3 solution,with an apparent quantum yield of 9.4%at 420 nm.Our findings suggest a new approach to the facile fabrication of nanostructured single-crystal photocatalysts for efficient solar water splitting,based on the use of metal nanopowders.
文摘超大规模集成电路Cu互连中的核心技术之一是制备性能优异的扩散阻挡层。本文采用直流磁控反应溅射在N2/Ar气氛中制备了不同组分比的Ta-N薄膜,并原位制备了Cu/Ta-N/基底复合结构,对部分样品在N2保护下进行了快速热处理(RTA),采用台阶仪、四探针测试仪、原子力显微镜(AFM)、扫描电镜、X射线衍射(XRD)对薄膜形貌结构进行了表征。结果表明,随着N2流量比的增加,薄膜沉积速率下降,表面趋于平滑,Ta-N薄膜热稳定性能及阻挡性能随之提高,而电阻率则上升。氮流量比为0.3制备的厚度为100nm的Ta-N薄膜经600℃/5m in RTA后,仍可保持对Cu的有效阻挡;在更高温度下退火,Cu将穿过阻挡层与Si发生反应,导致阻挡层失效。
