The soft deposition of Cu clusters on a Si （001） surface was studied by molecular dynamics simulations. The embedded atom method, the Stillinger-Weber and the Lennar-Jones potentials were used to describe the intera...The soft deposition of Cu clusters on a Si （001） surface was studied by molecular dynamics simulations. The embedded atom method, the Stillinger-Weber and the Lennar-Jones potentials were used to describe the interactions between the cluster atoms, between the substrate atoms, and between the cluster and the substrate atoms, respectively. The Cu13, Cu55, and Cu147 clusters were investigated at different substrate temperatures. We found that the substrate temperature had a significant effect on the Cn147 cluster. For smaller Cu13 and Cu55 clusters, the substrate temperature in the range of study appeared to have little effect on the mean center-of-mass height. The clusters showed better degrees of epitaxy at 800 K. With the same substrate temperature, the Cu55 cluster demonstrated the highest degree of epitaxy, followed by Cu147 and then Cu13 clusters. In addition, the Cu55 cluster showed the lowest mean center-of-mass height. These results suggested that the Cu55 cluster is a better choice for the thin-film formation among the clusters considered. Our studies may provide insight into the formation of desired Cu thin films on a Si substrate.展开更多
Copper thin films were deposited by plasma-enhanced atomic layer deposition at low temperature,using copper(I)-N,N′-di-sec-butylacetamidinate as a precursor and hydrogen as a reductive gas.The influence of temperatur...Copper thin films were deposited by plasma-enhanced atomic layer deposition at low temperature,using copper(I)-N,N′-di-sec-butylacetamidinate as a precursor and hydrogen as a reductive gas.The influence of temperature,plasma power,mode of plasma,and pulse time,on the deposition rate of copper thin film,the purity of the film and the step coverage were studied.The feasibility of copper film deposition on the inner wall of a carbon fibre reinforced plastic waveguide with high aspect ratio was also studied.The morphology and composition of the thin film were studied by atomic force microscopy and x-ray photoelectron spectroscopy,respectively.The square resistance of the thin film was also tested by a four-probe technique.On the basis of on-line diagnosis,a growth mechanism of copper thin film was put forward,and it was considered that surface functional group played an important role in the process of nucleation and in determining the properties of thin films.A high density of plasma and high free-radical content were helpful for the deposition of copper thin films.展开更多
The direct deposition of diamond films on copper substrate has been suffered fromadhesion problems due to the mismatch of the thermal expansion coefficients of diamond andcopper. In this paper nuclei with valuable den...The direct deposition of diamond films on copper substrate has been suffered fromadhesion problems due to the mismatch of the thermal expansion coefficients of diamond andcopper. In this paper nuclei with valuable density were directly introduced thirough a submicrondiamond powder layer. The diamond grits partially were buried in the copper substrate leadingto better adhesion. Another method with nickel intermediate layer for enhancing the adhesionwas studied here in detail. It was suggested that Cu-Ni eutectic between the copper substrate andNi interlayer might contribute to the adhesion improvement. The quality of the diamond filmsdeposited wlth rnckel interlayer was investigated by scanning electron microscopy and Ramanspectroscopy.展开更多
The deposition of high-quality diamond films and their adhesion on cemented carbides are strongly influenced by the catalytic effect of cobalt under typical deposition conditions. Decreasing Co content on the surface...The deposition of high-quality diamond films and their adhesion on cemented carbides are strongly influenced by the catalytic effect of cobalt under typical deposition conditions. Decreasing Co content on the surface of the cemented carbide is often used for the diamond film deposition. But the leaching of Co from the WC-Co substrate leading to a mechanical weak surface often causes a poor adhesion. In this paper we adopted an implant copper layer prepared by vaporization to improve the mechanical properties of the Co-leached substrate. The diamond films were grown by microwave plasma chemical vapor deposition from CH4:H2 gas mixture. The cross section and the morphology of the diamond film were characterized by scanning electron microscopy (SEM). The non-diamond content in the film was analyzed by Raman spectroscopy. The effects of pretreatment on the concentrations of Co and Cu near the interfacial region were examined by energy dispersive spectrum (EDS) equipped with SEM. The adhesion of the diamond on the substrate was evaluated with a Rockwell-type hardness tester. The results indicate that the diamond films prepared with implant copper layer have a good adhesion to the cemented carbide substrate due to the recovery of the mechanical properties of the Co-depleted substrate after the copper implantation and the formation of less amorphous carbon between the substrate and the diamond film.展开更多
由于存在大的温度梯度,激光熔化沉积过程会沿沉积方向形成具有择优取向的粗大柱状晶,导致材料产生显著的各向异性。拟通过在钛合金中添加Cu以实现改变初生β晶粒形态、细化组织并弱化织构的目的。系统研究了不同含量的Cu添加对激光熔化...由于存在大的温度梯度,激光熔化沉积过程会沿沉积方向形成具有择优取向的粗大柱状晶,导致材料产生显著的各向异性。拟通过在钛合金中添加Cu以实现改变初生β晶粒形态、细化组织并弱化织构的目的。系统研究了不同含量的Cu添加对激光熔化沉积TC4钛合金组织及织构的影响,结果表明,Cu元素能够显著细化柱状初生β晶粒,并使晶粒尺寸分布更加均匀,Cu元素添加量为4%(质量分数,下同)时能够实现完全的柱状晶向等轴晶转变,平均晶粒尺寸由未添加时的1490μm降低到385μm。添加Cu试样的晶粒内部仍为网篮组织,主要由α-Ti、β-Ti和少量Ti2Cu相组成,其中Ti2Cu呈短棒状分布在α-Ti板条的边界处,其在组织中的占比随Cu添加量的增大而增加。当添加8%Cu时,α-Ti的平均宽度为0.44μm,与未添加Cu试样的1.18μm相比降低了约63%。Cu添加能够显著降低激光熔化沉积钛合金的织构强度,当添加4%Cu时,α-Ti极图均匀分布倍数(multiples of uniform distribution,MUD)的最大值相比TC4降低了约71%。展开更多
Tantalum nitride （TAN） thin films are achieved on Si（111） and SS317L substrates by cathodic vacuum arc technique, which is rarely reported in the literature. The crystal structure, composition and surface morpholo...Tantalum nitride （TAN） thin films are achieved on Si（111） and SS317L substrates by cathodic vacuum arc technique, which is rarely reported in the literature. The crystal structure, composition and surface morphology of the films are characterized by x-ray diffraction （XRD）, x-ray photoelectron spectroscopy （XPS）, auger electron spectroscopy, and atomic force microscopy, respectively. The influence of substrate negative bias on crystal structure, composition, surface morphology of the TaN films is systematically studied. At the substrate bias of 0 V and -50 V, the amorphous TaN film is obtained. As the bias increases to -100 V, cubic TaN phase can be found. Stoichiometric TaN with hexagonal lattice preferred （300） orientation is prepared at a bias of -200 V. Combine the XRD and XPS results, the binding energy value of 23.6eV of Ta 4f（7/2） is contributed to hexagonal TaN. Compared to other techniques, TaN thin films fabricated by cathodic vacuum arc at various substrate biases show different microstructures.展开更多
A new method is proposed to prospect copper deposits with portable XRF analyzer. The method is based on the close relation between Cu and the chalcophile elements or some other elements in the geochemical anomalies of...A new method is proposed to prospect copper deposits with portable XRF analyzer. The method is based on the close relation between Cu and the chalcophile elements or some other elements in the geochemical anomalies of a Cu deposit. Applications of the technique in Northeast China are presented.展开更多
Nickel modification by spontaneous deposition of transition metals such as Ag and Cu is shown as an economic and simple alternative for the activation of hydrogen evolution reaction（HER） on cathodes in alkaline medi...Nickel modification by spontaneous deposition of transition metals such as Ag and Cu is shown as an economic and simple alternative for the activation of hydrogen evolution reaction（HER） on cathodes in alkaline media. The kinetics of HER is studied on Ni/Ag and Ni/Cu catalysts by cyclic voltammetry and electrochemical impedance spectroscopy（EIS） using a rotating disk electrode（RDE）. Freshly synthesized catalysts, as well as catalysts subjected to a short chronoamperometric ageing procedure, are analyzed and the kinetic and thermodynamic parameters of the HER are obtained. The nickel surface modified with transition metals with an outer shell electronic configuration [xd;（x+1）s;], such as Cu(3d;4s;)and Ag(4d;5s;), shows an improved activity for the HER compared to bare nickel. Furthermore, the Ni/Cu catalyst presents a decreased onset potential. The hydrogen evolution rate, measured as current density at –1.5 V（vs. SCE）, is similar on Ni/Cu and Ni/Ag electrodes.展开更多
The electroless copper deposition on both pure and Cr-coated diamond particles was stud- ied to produce copper/diamond composites for electronic packaging materials. The particles were characterized and the mechanism ...The electroless copper deposition on both pure and Cr-coated diamond particles was stud- ied to produce copper/diamond composites for electronic packaging materials. The particles were characterized and the mechanism of product formation was investigated through scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, X-ray diffraction （XRD）, and X-ray photoelectron spectra （XPS）. The particle coating thickness was measured using optical micro- graphs. The diamond particles got uniform coating thickness of copper crystals layers. This method provided an excellent base for the fabrication of metal-based composites using cheap equipments, and was less time consuming, nature friendly and economical compared with other methods of dia- mond surface metallization.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant No. 10375028)the US National Science Foundation Award (Grant No. CMMI-0700048)
文摘The soft deposition of Cu clusters on a Si （001） surface was studied by molecular dynamics simulations. The embedded atom method, the Stillinger-Weber and the Lennar-Jones potentials were used to describe the interactions between the cluster atoms, between the substrate atoms, and between the cluster and the substrate atoms, respectively. The Cu13, Cu55, and Cu147 clusters were investigated at different substrate temperatures. We found that the substrate temperature had a significant effect on the Cn147 cluster. For smaller Cu13 and Cu55 clusters, the substrate temperature in the range of study appeared to have little effect on the mean center-of-mass height. The clusters showed better degrees of epitaxy at 800 K. With the same substrate temperature, the Cu55 cluster demonstrated the highest degree of epitaxy, followed by Cu147 and then Cu13 clusters. In addition, the Cu55 cluster showed the lowest mean center-of-mass height. These results suggested that the Cu55 cluster is a better choice for the thin-film formation among the clusters considered. Our studies may provide insight into the formation of desired Cu thin films on a Si substrate.
文摘Copper thin films were deposited by plasma-enhanced atomic layer deposition at low temperature,using copper(I)-N,N′-di-sec-butylacetamidinate as a precursor and hydrogen as a reductive gas.The influence of temperature,plasma power,mode of plasma,and pulse time,on the deposition rate of copper thin film,the purity of the film and the step coverage were studied.The feasibility of copper film deposition on the inner wall of a carbon fibre reinforced plastic waveguide with high aspect ratio was also studied.The morphology and composition of the thin film were studied by atomic force microscopy and x-ray photoelectron spectroscopy,respectively.The square resistance of the thin film was also tested by a four-probe technique.On the basis of on-line diagnosis,a growth mechanism of copper thin film was put forward,and it was considered that surface functional group played an important role in the process of nucleation and in determining the properties of thin films.A high density of plasma and high free-radical content were helpful for the deposition of copper thin films.
文摘The direct deposition of diamond films on copper substrate has been suffered fromadhesion problems due to the mismatch of the thermal expansion coefficients of diamond andcopper. In this paper nuclei with valuable density were directly introduced thirough a submicrondiamond powder layer. The diamond grits partially were buried in the copper substrate leadingto better adhesion. Another method with nickel intermediate layer for enhancing the adhesionwas studied here in detail. It was suggested that Cu-Ni eutectic between the copper substrate andNi interlayer might contribute to the adhesion improvement. The quality of the diamond filmsdeposited wlth rnckel interlayer was investigated by scanning electron microscopy and Ramanspectroscopy.
文摘The deposition of high-quality diamond films and their adhesion on cemented carbides are strongly influenced by the catalytic effect of cobalt under typical deposition conditions. Decreasing Co content on the surface of the cemented carbide is often used for the diamond film deposition. But the leaching of Co from the WC-Co substrate leading to a mechanical weak surface often causes a poor adhesion. In this paper we adopted an implant copper layer prepared by vaporization to improve the mechanical properties of the Co-leached substrate. The diamond films were grown by microwave plasma chemical vapor deposition from CH4:H2 gas mixture. The cross section and the morphology of the diamond film were characterized by scanning electron microscopy (SEM). The non-diamond content in the film was analyzed by Raman spectroscopy. The effects of pretreatment on the concentrations of Co and Cu near the interfacial region were examined by energy dispersive spectrum (EDS) equipped with SEM. The adhesion of the diamond on the substrate was evaluated with a Rockwell-type hardness tester. The results indicate that the diamond films prepared with implant copper layer have a good adhesion to the cemented carbide substrate due to the recovery of the mechanical properties of the Co-depleted substrate after the copper implantation and the formation of less amorphous carbon between the substrate and the diamond film.
文摘由于存在大的温度梯度,激光熔化沉积过程会沿沉积方向形成具有择优取向的粗大柱状晶,导致材料产生显著的各向异性。拟通过在钛合金中添加Cu以实现改变初生β晶粒形态、细化组织并弱化织构的目的。系统研究了不同含量的Cu添加对激光熔化沉积TC4钛合金组织及织构的影响,结果表明,Cu元素能够显著细化柱状初生β晶粒,并使晶粒尺寸分布更加均匀,Cu元素添加量为4%(质量分数,下同)时能够实现完全的柱状晶向等轴晶转变,平均晶粒尺寸由未添加时的1490μm降低到385μm。添加Cu试样的晶粒内部仍为网篮组织,主要由α-Ti、β-Ti和少量Ti2Cu相组成,其中Ti2Cu呈短棒状分布在α-Ti板条的边界处,其在组织中的占比随Cu添加量的增大而增加。当添加8%Cu时,α-Ti的平均宽度为0.44μm,与未添加Cu试样的1.18μm相比降低了约63%。Cu添加能够显著降低激光熔化沉积钛合金的织构强度,当添加4%Cu时,α-Ti极图均匀分布倍数(multiples of uniform distribution,MUD)的最大值相比TC4降低了约71%。
文摘Tantalum nitride （TAN） thin films are achieved on Si（111） and SS317L substrates by cathodic vacuum arc technique, which is rarely reported in the literature. The crystal structure, composition and surface morphology of the films are characterized by x-ray diffraction （XRD）, x-ray photoelectron spectroscopy （XPS）, auger electron spectroscopy, and atomic force microscopy, respectively. The influence of substrate negative bias on crystal structure, composition, surface morphology of the TaN films is systematically studied. At the substrate bias of 0 V and -50 V, the amorphous TaN film is obtained. As the bias increases to -100 V, cubic TaN phase can be found. Stoichiometric TaN with hexagonal lattice preferred （300） orientation is prepared at a bias of -200 V. Combine the XRD and XPS results, the binding energy value of 23.6eV of Ta 4f（7/2） is contributed to hexagonal TaN. Compared to other techniques, TaN thin films fabricated by cathodic vacuum arc at various substrate biases show different microstructures.
文摘A new method is proposed to prospect copper deposits with portable XRF analyzer. The method is based on the close relation between Cu and the chalcophile elements or some other elements in the geochemical anomalies of a Cu deposit. Applications of the technique in Northeast China are presented.
基金financial support from Agencia Nacional de Promoción Científica y Tecnológica(PICT 1818)CONICET(PIP 00095)
文摘Nickel modification by spontaneous deposition of transition metals such as Ag and Cu is shown as an economic and simple alternative for the activation of hydrogen evolution reaction（HER） on cathodes in alkaline media. The kinetics of HER is studied on Ni/Ag and Ni/Cu catalysts by cyclic voltammetry and electrochemical impedance spectroscopy（EIS） using a rotating disk electrode（RDE）. Freshly synthesized catalysts, as well as catalysts subjected to a short chronoamperometric ageing procedure, are analyzed and the kinetic and thermodynamic parameters of the HER are obtained. The nickel surface modified with transition metals with an outer shell electronic configuration [xd;（x+1）s;], such as Cu(3d;4s;)and Ag(4d;5s;), shows an improved activity for the HER compared to bare nickel. Furthermore, the Ni/Cu catalyst presents a decreased onset potential. The hydrogen evolution rate, measured as current density at –1.5 V（vs. SCE）, is similar on Ni/Cu and Ni/Ag electrodes.
文摘The electroless copper deposition on both pure and Cr-coated diamond particles was stud- ied to produce copper/diamond composites for electronic packaging materials. The particles were characterized and the mechanism of product formation was investigated through scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, X-ray diffraction （XRD）, and X-ray photoelectron spectra （XPS）. The particle coating thickness was measured using optical micro- graphs. The diamond particles got uniform coating thickness of copper crystals layers. This method provided an excellent base for the fabrication of metal-based composites using cheap equipments, and was less time consuming, nature friendly and economical compared with other methods of dia- mond surface metallization.
