The controllable wire bonding of individual Ag nanowires onto a Au electrode was achieved at room temperature. The plastic deformation induced by pressure using nanoindentation could break the protective organic shell...The controllable wire bonding of individual Ag nanowires onto a Au electrode was achieved at room temperature. The plastic deformation induced by pressure using nanoindentation could break the protective organic shell on the surface of the Ag nanowires and cause atomic contact to promote the diffusion and nanojoining at the Ag and Au interface. Severe slip bands were observed in the Ag nanowires after the deformation. A metallic bond was formed at the interface, with the Ag diffusing into the Au more than the Au diffused into the Ag. This nanoscale wire bonding might present opportunities for nanoscale packaging and nanodevice design.展开更多
Carbon modified TiO_2 nanobelts(TiO_2-C) were synthesized using a hydrothermal growth method,as a support material for palladium(Pd) nanoparticles(Pd/TiO_2-C) to improve the electrocatalytic performance for methanol e...Carbon modified TiO_2 nanobelts(TiO_2-C) were synthesized using a hydrothermal growth method,as a support material for palladium(Pd) nanoparticles(Pd/TiO_2-C) to improve the electrocatalytic performance for methanol electrooxidation by comparison to Pd nanoparticles on bare TiO_2 nanobelts(Pd/TiO_2)and activated carbon(Pd/AC). Cyclic voltammetry characterization was conducted with respect to saturated calomel electrode(SCE) in an alkaline methanol solution, and the results indicate that the specific activity of Pd/TiO_2-C is 2.2 times that of Pd/AC and 1.5 times that of Pd/TiO_2. Chronoamperometry results revealed that the TiO_2-C support was comparable in stability to activated carbon, but possesses an enhanced current density for methanol oxidation at a potential of -0.2 V vs. SCE. The current study demonstrates the potential of Pd nanoparticle loaded on hierarchical TiO_2-C nanobelts for electrocatalytic applications such as fuel cells and batteries.展开更多
The ultrasonic wedge bonding with d25 μm copper wire was achieved on Au/Ni plated Cu substrate at ambient temperature.Ultrasonic wedge bonding mechanism was investigated by using SEM/EDX,pull test,shear test and micr...The ultrasonic wedge bonding with d25 μm copper wire was achieved on Au/Ni plated Cu substrate at ambient temperature.Ultrasonic wedge bonding mechanism was investigated by using SEM/EDX,pull test,shear test and microhardness test.The results show that the thinning of the Au layer occurs directly below the center of the bonding tool with the bonding power increasing.The interdiffusion between copper wire and Au metallization during the wedge bonding is assumed negligible,and the wedge bonding is achieved by wear action induced by ultrasonic vibration.The ultrasonic power contributes to enhance the deformation of copper wire due to ultrasonic softening effect which is then followed by the strain hardening of the copper wedge bonding.展开更多
We report the direct joining of carbon nanofibers(CNFs)to silver nanowire(Ag NWs)by controlled irradiation with femtosecond(fs)laser pulses.Two separate types of nano-junction dependent on joint geometry,laser fluence...We report the direct joining of carbon nanofibers(CNFs)to silver nanowire(Ag NWs)by controlled irradiation with femtosecond(fs)laser pulses.Two separate types of nano-junction dependent on joint geometry,laser fluence and irradiation time are identified in irradiated mixtures.In one type of junction,the tip of an Ag NW is melted and flows to form a bond with an adjacent CNF.The second type of junction occurs without significant heating of the Ag NW and involves the softening and flow of carbon in the CNF in response to the transfer of plasmonic energy from the Ag NW into the CNF.Bonding in a T-type joint configuration can be of either kind depending on the relative orientation of the incident optical field and the long axis of the Ag NW.FDTD simulations were used to explore this effect for different joint geometries and laser polarization.The electrical properties of a heterojunction involving a single Ag NW-CNF structure have been measured,and it is found that the junction resistance can be reduced by six orders of magnitude after laser joining.Finally,we have investigated the properties of a strain sensor based on an Ag NW-CNF hybrid nanowire network and find that this device can exhibit high sensitivity.This sensitivity occurs as nano-junctions induced by fs laser irradiation greatly reduces the initial resistance.This laser-based technique for direct nanojoining of CNF and Ag NWs may enable the design of robust nanowire structures for application in a variety of new devices.展开更多
基金supported by the National Natural Science Foundation of China(Grant Numbers 51375261,51520105007,51405258,51605019)support from the Beihang University,China,through Zhuoyue program
文摘The controllable wire bonding of individual Ag nanowires onto a Au electrode was achieved at room temperature. The plastic deformation induced by pressure using nanoindentation could break the protective organic shell on the surface of the Ag nanowires and cause atomic contact to promote the diffusion and nanojoining at the Ag and Au interface. Severe slip bands were observed in the Ag nanowires after the deformation. A metallic bond was formed at the interface, with the Ag diffusing into the Au more than the Au diffused into the Ag. This nanoscale wire bonding might present opportunities for nanoscale packaging and nanodevice design.
基金supported by FedDev Ontario through the Applied Research and Commercialization (ARC) Initiative and the Natural Sciences and Engineering Research Council of Canada (NSERC) programMicrobonds, Inc. for additional financial support
文摘Carbon modified TiO_2 nanobelts(TiO_2-C) were synthesized using a hydrothermal growth method,as a support material for palladium(Pd) nanoparticles(Pd/TiO_2-C) to improve the electrocatalytic performance for methanol electrooxidation by comparison to Pd nanoparticles on bare TiO_2 nanobelts(Pd/TiO_2)and activated carbon(Pd/AC). Cyclic voltammetry characterization was conducted with respect to saturated calomel electrode(SCE) in an alkaline methanol solution, and the results indicate that the specific activity of Pd/TiO_2-C is 2.2 times that of Pd/AC and 1.5 times that of Pd/TiO_2. Chronoamperometry results revealed that the TiO_2-C support was comparable in stability to activated carbon, but possesses an enhanced current density for methanol oxidation at a potential of -0.2 V vs. SCE. The current study demonstrates the potential of Pd nanoparticle loaded on hierarchical TiO_2-C nanobelts for electrocatalytic applications such as fuel cells and batteries.
基金Prpject(E052104/50705021)supported by the National Natural Science Foundation of ChinaProject(2006:01504489)supported by the Development Program for Outstanding Young Teachers in HIT
文摘The ultrasonic wedge bonding with d25 μm copper wire was achieved on Au/Ni plated Cu substrate at ambient temperature.Ultrasonic wedge bonding mechanism was investigated by using SEM/EDX,pull test,shear test and microhardness test.The results show that the thinning of the Au layer occurs directly below the center of the bonding tool with the bonding power increasing.The interdiffusion between copper wire and Au metallization during the wedge bonding is assumed negligible,and the wedge bonding is achieved by wear action induced by ultrasonic vibration.The ultrasonic power contributes to enhance the deformation of copper wire due to ultrasonic softening effect which is then followed by the strain hardening of the copper wedge bonding.
基金financially supported by the National Natural Science Foundation of China(No.U1730107)the National Natural Science Foundation of China(No.51522503)+2 种基金the Program for New Century Excellent Talents in University(No.NCET-13-0175)the Natural Sciences and Engineering Research Council(NSERC)of Canada and Canada Research Chairs(CRC)Programsthe China Scholarship Council(CSC)for the graduate fellowship。
文摘We report the direct joining of carbon nanofibers(CNFs)to silver nanowire(Ag NWs)by controlled irradiation with femtosecond(fs)laser pulses.Two separate types of nano-junction dependent on joint geometry,laser fluence and irradiation time are identified in irradiated mixtures.In one type of junction,the tip of an Ag NW is melted and flows to form a bond with an adjacent CNF.The second type of junction occurs without significant heating of the Ag NW and involves the softening and flow of carbon in the CNF in response to the transfer of plasmonic energy from the Ag NW into the CNF.Bonding in a T-type joint configuration can be of either kind depending on the relative orientation of the incident optical field and the long axis of the Ag NW.FDTD simulations were used to explore this effect for different joint geometries and laser polarization.The electrical properties of a heterojunction involving a single Ag NW-CNF structure have been measured,and it is found that the junction resistance can be reduced by six orders of magnitude after laser joining.Finally,we have investigated the properties of a strain sensor based on an Ag NW-CNF hybrid nanowire network and find that this device can exhibit high sensitivity.This sensitivity occurs as nano-junctions induced by fs laser irradiation greatly reduces the initial resistance.This laser-based technique for direct nanojoining of CNF and Ag NWs may enable the design of robust nanowire structures for application in a variety of new devices.
