In order to improve the wear and corrosion resistance of AZ31 magnesium alloy,a magnetron-sputtered Al layer with a thickness of 11μm was firstly applied on the alloy,and then treated by plasma electrolytic oxidation...In order to improve the wear and corrosion resistance of AZ31 magnesium alloy,a magnetron-sputtered Al layer with a thickness of 11μm was firstly applied on the alloy,and then treated by plasma electrolytic oxidation(PEO)in an aluminate and silicate electrolytes,respectively.The performance of PEO coatings was investigated by dry sliding wear and electrochemical corrosion tests.The aluminate coating exhibits excellent wear resistance under both 10 and 20 N loads.The silicate coating only shows low wear rate under 10 N,but it was destroyed under 20 N.Corrosion tests show that the Al layer after magnetron sputtering treatment alone cannot afford good protection to the Mg substrate.However,the duplex layer of PEO/Al can significantly improve the corrosion resistance of AZ31 alloy.Electrochemical tests show that the aluminate and silicate coatings have corrosion current densities of-1.6×10^(-6) and-1.1×10^(-6) A/cm^(2),respectively,which are two orders lower than that of the un-coated AZ31 alloy.However,immersion tests and electrochemical impedance spectroscopy(EIS)show that the aluminate coating exhibits better long-term corrosion protection than silicate coating.展开更多
The technique to improve the performance of W/TiN stacked gate MOS capacitor with 3nm gate oxide is reported by optimizing the sputtering process of a refractory metal gate electrode and adopting a proper anneal tempe...The technique to improve the performance of W/TiN stacked gate MOS capacitor with 3nm gate oxide is reported by optimizing the sputtering process of a refractory metal gate electrode and adopting a proper anneal temperature to eliminate the damages.Specific methods involved in the optimization of sputtering process include:selecting a proper TiN thickness to reduce stresses;using a smaller sputtering rate to suppress the damages to gate dielectric and adopting a higher N 2/Ar ratio during the TiN sputtering process to further nitride the gate dielectric.With these measures,excellent C V curves are obtained and surface state density ( N ss ) is successfully reduced to below 8×10 10 cm -2 ,which is comparable to the polysilicon gate MOS capacitor.展开更多
We report a newly constructed laser ablation crossed molecular beam apparatus, equipped with time-sliced velocity map imaging technique, to study state-to-state metal atom reaction dynamics. Supersonic metal atomic be...We report a newly constructed laser ablation crossed molecular beam apparatus, equipped with time-sliced velocity map imaging technique, to study state-to-state metal atom reaction dynamics. Supersonic metal atomic beam is generated by laser vaporization of metal rod, and free expansion design without gas flow channel has been employed to obtain a good quality of metal atomic beam. We have chosen the crossed-beam reaction Al＋O2 to test the performance of the new apparatus. Two-rotational-states selected AIO（X^2∑＋, v=0, N and N＋I4） products can be imaged via P（N） and R（N＋14） branches of the Av=l band at the same wavelength, during （1＋1） resonance-enhanced multi-photon ionization through the AIO（D2E＋） intermediate state. In our experiment at 244.145 nm for simultaneous transitions of P（15） and R（29） branch, two rings in slice image were clearly distinguishable, corresponding to the AiO（v=0, N=IS） and AIO（v=0, N=29） states respectively. The energy difference between the two rotational levels is 403 cm^-1. The success of two states resolved in our apparatus suggests a better collisional energy resolution compared with the recent research study [J. Chem. Phys. 140, 214304 （2014）].展开更多
To improve the characteristics of a diamond-like carbon （DLC） film, Ti-containing amorphous hydrogenated carbon thin films were deposited on sus304 stainless steel substrates by high-power plasma-sputtering with tit...To improve the characteristics of a diamond-like carbon （DLC） film, Ti-containing amorphous hydrogenated carbon thin films were deposited on sus304 stainless steel substrates by high-power plasma-sputtering with titanium metal as the solid plasma source in a mixed ArC2H2 atmosphere. The films were fabricated to obtain a multilayered structure of Ti/TiC/DLC gradient for improving adhesion and reducing residual stress. The effects of substrate bias and target-substrate distance on the films＇ properties were studied by glow discharge spectroscope, X-ray diffractometer, Raman spectroscope, nanoindenter, and a pin-on-disk tribometer. The results indicate that the films possess superior adhesive strength and toughness.展开更多
We report the dispersion and scanning tunneling microscopy （STM） characterization of iso- lated Au-CdSe nanohybrids on atomically fiat Au（111） through surface modifications. The top terminal groups of spacer molec...We report the dispersion and scanning tunneling microscopy （STM） characterization of iso- lated Au-CdSe nanohybrids on atomically fiat Au（111） through surface modifications. The top terminal groups of spacer molecules self-assembled on the surface are found critical for locking the nanohybrids into a well-separated state. The STM results indicate that both thiol and carboxylic terminals are effective in this aspect by making strong interaction with the Au portions of the nanohybrids. An argon ion sputtering technique is also proposed to clean up organic contaminants on the surface for improved STM imaging of individual Au-CdSe nanohybrids. These observations help to enrich technical approaches to dispersing individual nanostructures on the surface and provide opportunities to explore their local electroluminescent and energy transfer properties at the nanoscale.展开更多
Using collection film technique combined with Auger electron spectroscopy is analysis, the preferential sputtering of the ternary alloy Cu76Ni15Sn9 bombarded with 27 keV Ar+ at normal incidence is studied. After bomba...Using collection film technique combined with Auger electron spectroscopy is analysis, the preferential sputtering of the ternary alloy Cu76Ni15Sn9 bombarded with 27 keV Ar+ at normal incidence is studied. After bombardment, the target surfaCe is examined with SEM, and the surface composition of different topographical feature areas is measured with electron probe micrthanalyser (EPMA). The experiment results show that Cu atoms are preferentially ejected compared with Ni atoms, and Sn atoms come third within the ejection angle range from 0° to 60°. The results are discussed from the viewpoint of sputtering from a very rough surface.展开更多
Functionalized implants demonstrate an upgraded approach in orthopedic implants,aiming to achieve long term success through improved bio integration.Bioceramic coatings with multifunctionality have arisen as an effect...Functionalized implants demonstrate an upgraded approach in orthopedic implants,aiming to achieve long term success through improved bio integration.Bioceramic coatings with multifunctionality have arisen as an effective substitute for conventional coatings,owing to their combination of various properties that are essential for bio-implants,such as osteointegration and antibacterial character.In the present study,thin hopeite coatings were produced by Pulsed laser deposition(PLD)and radio frequency magnetron sputtering(RFMS)on Ti64 substrates.The obtained hopeite coatings were annealed at 500°C in ambient air and studied in terms of surface morphology,phase composition,surface roughness,adhesion strength,antibacterial efficacy,apatite forming ability,and surface wettability by scanning electron microscope(SEM),X-ray diffraction(XRD),atomic force microscope(AFM),tensometer,fluorescence-activated cell sorting(FACS),simulated body fluid(SBF)immersion test and contact angle goniometer,respectively.Furthermore,based on promising results obtained in the present work it can be summarized that the new generation multifunctional hopeite coating synthesized by two alternative new process routes of PLD and RFMS on Ti64 substrates,provides effective alternatives to conventional coatings,largely attributed to strong osteointegration and antibacterial character of deposited hopeite coating ensuring the overall stability of metallic orthopedic implants.展开更多
The reaction dynamics of yttrium atoms with sulfur dioxide molecules at a high collision energy of 36 kcal/mol was studied using time-sliced velocity map ion imaging,crossed molecular beam and laser-ablation method.Th...The reaction dynamics of yttrium atoms with sulfur dioxide molecules at a high collision energy of 36 kcal/mol was studied using time-sliced velocity map ion imaging,crossed molecular beam and laser-ablation method.The product YO was detected via multiphoton ionization at various wavelengths in the region of 482-615 nm.The slice images of YO show a broad velocity distribution and forward-backward peaking angular distribution.The forward scattering signal is stronger than its backward distribution.This indicates that the reaction proceeds via an intermediate complex and the lifetime of the intermediate state is less than one rotational period.The formation of complex suggests that electron transfer occurs in the oxidation reaction.展开更多
One of the themes of modern molecular reac tion dynamics is to charac terize elementary chemical reactions from“quan tum state to quan tum stat e”,and the study of molecular reaction dynamics in excited states can h...One of the themes of modern molecular reac tion dynamics is to charac terize elementary chemical reactions from“quan tum state to quan tum stat e”,and the study of molecular reaction dynamics in excited states can help test the validi ty of modern chemical t heories and provide met hods to cont rol chemical reactions.The subject of this review is to describe the recent experimental techniques used to study the reaction dynamics of metal atoms in the gas phase.Through these techniques,information such as the internal energy distribution and angular distribution of the nascent products or the three-dimensional stereodynamic reactivity can be obtained.In addition,by preparing metal at oms wi th specific exci ted elec tronic states or orbi tal arrangemen ts,information about the reactivity of the electronic states enriches the relevant understanding of the electron transfer mechanism in metal reaction dynamics.展开更多
Pure Cu films and Cu alloy films containing insoluble substances(Zr and Cr)were deposited on Si(100)substrates,in the presence of interfacial native suboxide(SiOx),by magnetron sputtering.Samples were vacuum annealed ...Pure Cu films and Cu alloy films containing insoluble substances(Zr and Cr)were deposited on Si(100)substrates,in the presence of interfacial native suboxide(SiOx),by magnetron sputtering.Samples were vacuum annealed between 300℃and 500 ℃to investigate effects of Zr and Cr additions on the thermal performance of Cu films.After annealing,copper silicides were found in the Cu(Zr)films,while no detectable silicides were observed in Cu and Cu(Cr)films.Upon annealing,Zr accelerated the diffusion and reaction between the film and the substrate,and lowered the thermal stability of Cu(Zr)alloy films on Si substrates,which was ascribed to the‘purifying effect’of Zr on the Si substrates.Whereas,Cr prohibited the agglomeration of Cu films at 500℃and decreased the surface roughness.As a result,the diffusion of Cu in Si substrates for Cu(Cr)films was effectively inhibited.In contrast to the high resistivity of Cu(Zr)films,the final resistivity of about 2.76μΩ·cm was achieved for the Cu(Cr)film.These results indicate that Cu(Cr)films have higher thermal stability than Cu(Zr)films on Si substrates and are preferable in the advanced barrierless Cu metallization.展开更多
A uniform and dense TiO2 film was grown on the surface of porous NiTi shape memory alloys(SMAs) successfully by RF magnetron sputtering.The morphology and composition of the surface film were analyzed by using scannin...A uniform and dense TiO2 film was grown on the surface of porous NiTi shape memory alloys(SMAs) successfully by RF magnetron sputtering.The morphology and composition of the surface film were analyzed by using scanning electron microscopy and X-ray photoelectron spectroscopy.The corrosion resistance measurement proved that the surface modified porous NiTi SMAs exhibit better corrosion resistance and over 25% reduction of Ni ion release in the blood of the rabbits in comparing with the samples without surface modification.Moreover,the biocompatibility,as demonstrated by cell adherence and implant surgery,revealed that the cell adherence and bone tissue inducing capability are respectively enhanced over 1.1-1.2 and 9-10 times by sputtering a uniform TiO2 film on the surfaces of porous NiTi SMAs.展开更多
A novel optical fiber hydrogen sensing system based on palladium(Pd) and sliver(Ag) is proposed. By direct current(DC) magnetron process, Pd/Ag alloy ultra-thin films were deposited on the substrate to eliminate the h...A novel optical fiber hydrogen sensing system based on palladium(Pd) and sliver(Ag) is proposed. By direct current(DC) magnetron process, Pd/Ag alloy ultra-thin films were deposited on the substrate to eliminate the hydrogen embrittlement of sensor based on pure Pd. Several samples with different thin film thicknesses were fabricated at different substrate temperatures and tested in the optical fiber hydrogen sensor setup. We do a series of experiments for obtaining optimum sputtering parameters, such as optimum sputtering temperature and thickness of Pd/Ag alloy film. The humidity effect and reliability experiment for the optical fiber hydrogen gas sensor are reported in detail. The testing results demonstrate the Pd/Ag alloy is a promising material for optical fiber hydrogen gas sensor.展开更多
基金the National Natural Science Foundation of China(No.51671084)。
文摘In order to improve the wear and corrosion resistance of AZ31 magnesium alloy,a magnetron-sputtered Al layer with a thickness of 11μm was firstly applied on the alloy,and then treated by plasma electrolytic oxidation(PEO)in an aluminate and silicate electrolytes,respectively.The performance of PEO coatings was investigated by dry sliding wear and electrochemical corrosion tests.The aluminate coating exhibits excellent wear resistance under both 10 and 20 N loads.The silicate coating only shows low wear rate under 10 N,but it was destroyed under 20 N.Corrosion tests show that the Al layer after magnetron sputtering treatment alone cannot afford good protection to the Mg substrate.However,the duplex layer of PEO/Al can significantly improve the corrosion resistance of AZ31 alloy.Electrochemical tests show that the aluminate and silicate coatings have corrosion current densities of-1.6×10^(-6) and-1.1×10^(-6) A/cm^(2),respectively,which are two orders lower than that of the un-coated AZ31 alloy.However,immersion tests and electrochemical impedance spectroscopy(EIS)show that the aluminate coating exhibits better long-term corrosion protection than silicate coating.
文摘The technique to improve the performance of W/TiN stacked gate MOS capacitor with 3nm gate oxide is reported by optimizing the sputtering process of a refractory metal gate electrode and adopting a proper anneal temperature to eliminate the damages.Specific methods involved in the optimization of sputtering process include:selecting a proper TiN thickness to reduce stresses;using a smaller sputtering rate to suppress the damages to gate dielectric and adopting a higher N 2/Ar ratio during the TiN sputtering process to further nitride the gate dielectric.With these measures,excellent C V curves are obtained and surface state density ( N ss ) is successfully reduced to below 8×10 10 cm -2 ,which is comparable to the polysilicon gate MOS capacitor.
基金We are indebted to Prof. Kopin Liu （IAMS, Taipei） for stimulating discussions on going experiments, to Prof. Ming-fei Zhou and Assoc. Prof. Guan-jun Wang （Fudan University, Shanghai） for assistance in building machine, to Prof. Uzi. Even （Tel Aviv University, Tel Aviv） for discussions oil E1 valve employnmnt in laser ablation, and to Prof. Xue-ming Yang＇s group （DICP, Dalian） for new Iaser system. This work was supported by the National Natural Science Foundation of China （No.21322309） and the Program for Professor of Special Appointment （Eastern Scholar） at Shanghai Institutions of Higher Learning.
文摘We report a newly constructed laser ablation crossed molecular beam apparatus, equipped with time-sliced velocity map imaging technique, to study state-to-state metal atom reaction dynamics. Supersonic metal atomic beam is generated by laser vaporization of metal rod, and free expansion design without gas flow channel has been employed to obtain a good quality of metal atomic beam. We have chosen the crossed-beam reaction Al＋O2 to test the performance of the new apparatus. Two-rotational-states selected AIO（X^2∑＋, v=0, N and N＋I4） products can be imaged via P（N） and R（N＋14） branches of the Av=l band at the same wavelength, during （1＋1） resonance-enhanced multi-photon ionization through the AIO（D2E＋） intermediate state. In our experiment at 244.145 nm for simultaneous transitions of P（15） and R（29） branch, two rings in slice image were clearly distinguishable, corresponding to the AiO（v=0, N=IS） and AIO（v=0, N=29） states respectively. The energy difference between the two rotational levels is 403 cm^-1. The success of two states resolved in our apparatus suggests a better collisional energy resolution compared with the recent research study [J. Chem. Phys. 140, 214304 （2014）].
文摘To improve the characteristics of a diamond-like carbon （DLC） film, Ti-containing amorphous hydrogenated carbon thin films were deposited on sus304 stainless steel substrates by high-power plasma-sputtering with titanium metal as the solid plasma source in a mixed ArC2H2 atmosphere. The films were fabricated to obtain a multilayered structure of Ti/TiC/DLC gradient for improving adhesion and reducing residual stress. The effects of substrate bias and target-substrate distance on the films＇ properties were studied by glow discharge spectroscope, X-ray diffractometer, Raman spectroscope, nanoindenter, and a pin-on-disk tribometer. The results indicate that the films possess superior adhesive strength and toughness.
文摘We report the dispersion and scanning tunneling microscopy （STM） characterization of iso- lated Au-CdSe nanohybrids on atomically fiat Au（111） through surface modifications. The top terminal groups of spacer molecules self-assembled on the surface are found critical for locking the nanohybrids into a well-separated state. The STM results indicate that both thiol and carboxylic terminals are effective in this aspect by making strong interaction with the Au portions of the nanohybrids. An argon ion sputtering technique is also proposed to clean up organic contaminants on the surface for improved STM imaging of individual Au-CdSe nanohybrids. These observations help to enrich technical approaches to dispersing individual nanostructures on the surface and provide opportunities to explore their local electroluminescent and energy transfer properties at the nanoscale.
文摘Using collection film technique combined with Auger electron spectroscopy is analysis, the preferential sputtering of the ternary alloy Cu76Ni15Sn9 bombarded with 27 keV Ar+ at normal incidence is studied. After bombardment, the target surfaCe is examined with SEM, and the surface composition of different topographical feature areas is measured with electron probe micrthanalyser (EPMA). The experiment results show that Cu atoms are preferentially ejected compared with Ni atoms, and Sn atoms come third within the ejection angle range from 0° to 60°. The results are discussed from the viewpoint of sputtering from a very rough surface.
文摘Functionalized implants demonstrate an upgraded approach in orthopedic implants,aiming to achieve long term success through improved bio integration.Bioceramic coatings with multifunctionality have arisen as an effective substitute for conventional coatings,owing to their combination of various properties that are essential for bio-implants,such as osteointegration and antibacterial character.In the present study,thin hopeite coatings were produced by Pulsed laser deposition(PLD)and radio frequency magnetron sputtering(RFMS)on Ti64 substrates.The obtained hopeite coatings were annealed at 500°C in ambient air and studied in terms of surface morphology,phase composition,surface roughness,adhesion strength,antibacterial efficacy,apatite forming ability,and surface wettability by scanning electron microscope(SEM),X-ray diffraction(XRD),atomic force microscope(AFM),tensometer,fluorescence-activated cell sorting(FACS),simulated body fluid(SBF)immersion test and contact angle goniometer,respectively.Furthermore,based on promising results obtained in the present work it can be summarized that the new generation multifunctional hopeite coating synthesized by two alternative new process routes of PLD and RFMS on Ti64 substrates,provides effective alternatives to conventional coatings,largely attributed to strong osteointegration and antibacterial character of deposited hopeite coating ensuring the overall stability of metallic orthopedic implants.
基金supported by the National Natural Science Foundation of China (No.21673047,No.21327901and No.21573047)the Shanghai Key Laboratory Foundation of Molecular Catalysis and Innovative Materialsthe Program for Professor of Special Appointment(Eastern Scholar) at Shanghai Institutions of Higher Learning.
文摘The reaction dynamics of yttrium atoms with sulfur dioxide molecules at a high collision energy of 36 kcal/mol was studied using time-sliced velocity map ion imaging,crossed molecular beam and laser-ablation method.The product YO was detected via multiphoton ionization at various wavelengths in the region of 482-615 nm.The slice images of YO show a broad velocity distribution and forward-backward peaking angular distribution.The forward scattering signal is stronger than its backward distribution.This indicates that the reaction proceeds via an intermediate complex and the lifetime of the intermediate state is less than one rotational period.The formation of complex suggests that electron transfer occurs in the oxidation reaction.
基金The work was supported by the National Natural Science Foundation of China(No.21673047 and No.22073019)the Shanghai Key Laboratory Foundation of Molecular Catalysis and Innovative Materialsthe Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning.
文摘One of the themes of modern molecular reac tion dynamics is to charac terize elementary chemical reactions from“quan tum state to quan tum stat e”,and the study of molecular reaction dynamics in excited states can help test the validi ty of modern chemical t heories and provide met hods to cont rol chemical reactions.The subject of this review is to describe the recent experimental techniques used to study the reaction dynamics of metal atoms in the gas phase.Through these techniques,information such as the internal energy distribution and angular distribution of the nascent products or the three-dimensional stereodynamic reactivity can be obtained.In addition,by preparing metal at oms wi th specific exci ted elec tronic states or orbi tal arrangemen ts,information about the reactivity of the electronic states enriches the relevant understanding of the electron transfer mechanism in metal reaction dynamics.
基金Project(08520740200)supported by the Applied Materials Research and Development Fund of Shanghai,China
文摘Pure Cu films and Cu alloy films containing insoluble substances(Zr and Cr)were deposited on Si(100)substrates,in the presence of interfacial native suboxide(SiOx),by magnetron sputtering.Samples were vacuum annealed between 300℃and 500 ℃to investigate effects of Zr and Cr additions on the thermal performance of Cu films.After annealing,copper silicides were found in the Cu(Zr)films,while no detectable silicides were observed in Cu and Cu(Cr)films.Upon annealing,Zr accelerated the diffusion and reaction between the film and the substrate,and lowered the thermal stability of Cu(Zr)alloy films on Si substrates,which was ascribed to the‘purifying effect’of Zr on the Si substrates.Whereas,Cr prohibited the agglomeration of Cu films at 500℃and decreased the surface roughness.As a result,the diffusion of Cu in Si substrates for Cu(Cr)films was effectively inhibited.In contrast to the high resistivity of Cu(Zr)films,the final resistivity of about 2.76μΩ·cm was achieved for the Cu(Cr)film.These results indicate that Cu(Cr)films have higher thermal stability than Cu(Zr)films on Si substrates and are preferable in the advanced barrierless Cu metallization.
基金supported by the National Natural Science Foundation of China (Grant No. 50701019)the Fundamental Research Funds for the Central Universities (Grant No. 2009ZM0258)the Guangdong Provincial Science and Technology Project (Grant No. 2010B031100004)
文摘A uniform and dense TiO2 film was grown on the surface of porous NiTi shape memory alloys(SMAs) successfully by RF magnetron sputtering.The morphology and composition of the surface film were analyzed by using scanning electron microscopy and X-ray photoelectron spectroscopy.The corrosion resistance measurement proved that the surface modified porous NiTi SMAs exhibit better corrosion resistance and over 25% reduction of Ni ion release in the blood of the rabbits in comparing with the samples without surface modification.Moreover,the biocompatibility,as demonstrated by cell adherence and implant surgery,revealed that the cell adherence and bone tissue inducing capability are respectively enhanced over 1.1-1.2 and 9-10 times by sputtering a uniform TiO2 film on the surfaces of porous NiTi SMAs.
基金supported by the National Natural Science Foundation of China(No.51505506)the Science and Technology Research Key Project of Henan Provincial Education Department(No.13A460118)the Science and Technology Tackling Key Project of Henan Province(No.152102210362)
文摘A novel optical fiber hydrogen sensing system based on palladium(Pd) and sliver(Ag) is proposed. By direct current(DC) magnetron process, Pd/Ag alloy ultra-thin films were deposited on the substrate to eliminate the hydrogen embrittlement of sensor based on pure Pd. Several samples with different thin film thicknesses were fabricated at different substrate temperatures and tested in the optical fiber hydrogen sensor setup. We do a series of experiments for obtaining optimum sputtering parameters, such as optimum sputtering temperature and thickness of Pd/Ag alloy film. The humidity effect and reliability experiment for the optical fiber hydrogen gas sensor are reported in detail. The testing results demonstrate the Pd/Ag alloy is a promising material for optical fiber hydrogen gas sensor.
