High-purity germanium(HPGe)detectors,which are used for direct dark matter detection,have the advantages of a low threshold and excellent energy resolution.The surface passivation of HPGe has become crucial for achiev...High-purity germanium(HPGe)detectors,which are used for direct dark matter detection,have the advantages of a low threshold and excellent energy resolution.The surface passivation of HPGe has become crucial for achieving an extremely low energy threshold.In this study,first-principles simulations,passivation film preparation,and metal oxide semiconductor(MOS)capacitor characterization were combined to study surface passivation.Theoretical calculations of the energy band structure of the -H,-OH,and -NH_(2) passivation groups on the surface of Ge were performed,and the interface state density and potential with five different passivation groups with N/O atomic ratios were accurately analyzed to obtain a stable surface state.Based on the theoretical calculation results,the surface passivation layers of the Ge_(2)ON_(2) film were prepared via magnetron sputtering in accordance with the optimum atomic ratio structure.The microstructure,C-V,and I-V electrical properties of the layers,and the passivation effect of the Al/Ge_(2)ON_(2)/Ge MOS were characterized to test the interface state density.The mean interface state density obtained by the Terman method was 8.4×10^(11) cm^(-2) eV^(-1).The processing of germanium oxynitrogen passivation films is expected to be used in direct dark matter detection of the HPGe detector surface passivation technology to reduce the detector leakage currents.展开更多
同步加速器放射光致核裂变光谱学被用来在 Si 上在取向附生的生长期间学习 Er2O3/Si (001 ) 接口和电影的形成过程。在 O 核心级的有约束力的精力的移动被发现被移动在 Er2O3 原子价乐队最大值伴随了。这移动取决于氧化物层厚度和界面...同步加速器放射光致核裂变光谱学被用来在 Si 上在取向附生的生长期间学习 Er2O3/Si (001 ) 接口和电影的形成过程。在 O 核心级的有约束力的精力的移动被发现被移动在 Er2O3 原子价乐队最大值伴随了。这移动取决于氧化物层厚度和界面的结构。界面的层在 Si 上在 Er2O3 电影的起始的生长被观察，它应当被归因于效果嗯原子催化氧化效果。展开更多
HfO2 films on silicon substrates have been prepared by electron beam evaporation in ultrahigh vacuum using atomic oxygen. Synchrotron radiation photon-electron spectroscopy was used to investigate the thermal stabilit...HfO2 films on silicon substrates have been prepared by electron beam evaporation in ultrahigh vacuum using atomic oxygen. Synchrotron radiation photon-electron spectroscopy was used to investigate the thermal stability of HfO2 films under an ultrahigh vacuum environment. At the temperature of 750 ℃, HfO2 films begin to decompose. After being further annealed at 850℃ for 3 min, HfO2 films decomposes completely, partially to form Hf-silicide and partially to form gaseous HfO. Two chemical reactions are responsible for this decomposition process. A small amount of Hf-silicide, which is formed at the very beginning of growth, may result in the films grown subsequently to be loosened, and thereby leads to a relatively low decomposition temperature.展开更多
The oxidation behavior of alloy 690 exposed to high-temperature and high-pressure steam and water at 280℃ for 1 h was investigated by scanning electron microscopy （SEM）, atomic force microscopy （AFM） and X-ray ph...The oxidation behavior of alloy 690 exposed to high-temperature and high-pressure steam and water at 280℃ for 1 h was investigated by scanning electron microscopy （SEM）, atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS）. In high-temperature and high-pressure steam, the oxide film is composed of an outermost Ni-rich hydroxides layer, an intermediate layer of hydroxides and oxides enriched in Cr, an inner oxide layer. The film formed in high-temperature water is similar to that in steam, except for missing the Ni-rich hydroxides layer. Samples with different surface finishes （electropolished, mechanically polished, ground, and as-received） were prepared for comparison. A general increase of the oxide thickness with the degree of surface roughness is observed. The equivalent oxide thicknesses lie in the range of 100-200 nm for the as-received samples, 150-250 nm for the samples ground to 400# and 10-20 nm for the samples ground to 1500#, mechanically polished, and electropolished.展开更多
A comparative evaluation of the friction and wear behaviors of 40CrNiMoA steel and Inconel 718 alloy sliding against Si_(3)N_(4) counterparts was conducted over a large temperature range from room temperature(RT)to 80...A comparative evaluation of the friction and wear behaviors of 40CrNiMoA steel and Inconel 718 alloy sliding against Si_(3)N_(4) counterparts was conducted over a large temperature range from room temperature(RT)to 800℃.The temperature‐dependent tribological properties associated with the resulting chemical mitigation and structural adaptation of the solid sliding surface were clarified by surface/interface characterizations.The results revealed desirable performance in reducing friction and wear at elevated temperatures,which was associated with the resulting oxide composite filmʹs adaptive lubricating capability,whereas severe abrasive wear occurred at room/ambient temperatures.The oxidative‐abrasive differentials for the two alloys were further discussed by considering the combined effect of temperature and stressed‐shearing conditions.展开更多
基金supported by the National Natural Science Foundation of China(No.12005017).
文摘High-purity germanium(HPGe)detectors,which are used for direct dark matter detection,have the advantages of a low threshold and excellent energy resolution.The surface passivation of HPGe has become crucial for achieving an extremely low energy threshold.In this study,first-principles simulations,passivation film preparation,and metal oxide semiconductor(MOS)capacitor characterization were combined to study surface passivation.Theoretical calculations of the energy band structure of the -H,-OH,and -NH_(2) passivation groups on the surface of Ge were performed,and the interface state density and potential with five different passivation groups with N/O atomic ratios were accurately analyzed to obtain a stable surface state.Based on the theoretical calculation results,the surface passivation layers of the Ge_(2)ON_(2) film were prepared via magnetron sputtering in accordance with the optimum atomic ratio structure.The microstructure,C-V,and I-V electrical properties of the layers,and the passivation effect of the Al/Ge_(2)ON_(2)/Ge MOS were characterized to test the interface state density.The mean interface state density obtained by the Terman method was 8.4×10^(11) cm^(-2) eV^(-1).The processing of germanium oxynitrogen passivation films is expected to be used in direct dark matter detection of the HPGe detector surface passivation technology to reduce the detector leakage currents.
基金supported by the Special Project of Shanghai Nano Technology (0852nm02400 and 0752nm012)Shaoxing Science and Technology Commission (2007A21015)+3 种基金Shanghai Rising-Star Program (07QA14026)the National Natural Science Foundation of China (10804072)the Key Fundamental Project of Shanghai (08JC1410400)Shanghai Education Commission (07zz143)
文摘同步加速器放射光致核裂变光谱学被用来在 Si 上在取向附生的生长期间学习 Er2O3/Si (001 ) 接口和电影的形成过程。在 O 核心级的有约束力的精力的移动被发现被移动在 Er2O3 原子价乐队最大值伴随了。这移动取决于氧化物层厚度和界面的结构。界面的层在 Si 上在 Er2O3 电影的起始的生长被观察，它应当被归因于效果嗯原子催化氧化效果。
基金Project supported by the National Natural Science Foundation of China (Grant No. 60877017)the Shanghai Leading Academic Disciplines Foundation (Grant No. S30107)the Innovation Program of Shanghai Municipal Education Commission (GrantNo. 08YZ04)
文摘HfO2 films on silicon substrates have been prepared by electron beam evaporation in ultrahigh vacuum using atomic oxygen. Synchrotron radiation photon-electron spectroscopy was used to investigate the thermal stability of HfO2 films under an ultrahigh vacuum environment. At the temperature of 750 ℃, HfO2 films begin to decompose. After being further annealed at 850℃ for 3 min, HfO2 films decomposes completely, partially to form Hf-silicide and partially to form gaseous HfO. Two chemical reactions are responsible for this decomposition process. A small amount of Hf-silicide, which is formed at the very beginning of growth, may result in the films grown subsequently to be loosened, and thereby leads to a relatively low decomposition temperature.
基金supported by the Special Funds for the Major State Basic Research Projects(G2011CB610502)the National Natural Science Foundation of China (No.51025104)
文摘The oxidation behavior of alloy 690 exposed to high-temperature and high-pressure steam and water at 280℃ for 1 h was investigated by scanning electron microscopy （SEM）, atomic force microscopy （AFM） and X-ray photoelectron spectroscopy （XPS）. In high-temperature and high-pressure steam, the oxide film is composed of an outermost Ni-rich hydroxides layer, an intermediate layer of hydroxides and oxides enriched in Cr, an inner oxide layer. The film formed in high-temperature water is similar to that in steam, except for missing the Ni-rich hydroxides layer. Samples with different surface finishes （electropolished, mechanically polished, ground, and as-received） were prepared for comparison. A general increase of the oxide thickness with the degree of surface roughness is observed. The equivalent oxide thicknesses lie in the range of 100-200 nm for the as-received samples, 150-250 nm for the samples ground to 400# and 10-20 nm for the samples ground to 1500#, mechanically polished, and electropolished.
基金The research received great support from the National Natural Science Foundation of China(Nos.51575505 and 51675508)The work is also funded by Australian Research Council(ARC)Discovery Project(DP)(No.150103718).
文摘A comparative evaluation of the friction and wear behaviors of 40CrNiMoA steel and Inconel 718 alloy sliding against Si_(3)N_(4) counterparts was conducted over a large temperature range from room temperature(RT)to 800℃.The temperature‐dependent tribological properties associated with the resulting chemical mitigation and structural adaptation of the solid sliding surface were clarified by surface/interface characterizations.The results revealed desirable performance in reducing friction and wear at elevated temperatures,which was associated with the resulting oxide composite filmʹs adaptive lubricating capability,whereas severe abrasive wear occurred at room/ambient temperatures.The oxidative‐abrasive differentials for the two alloys were further discussed by considering the combined effect of temperature and stressed‐shearing conditions.
