Fe－Cu包埋团簇的制备及其微观结构的研究

基于溅射－气体－聚集（ＳＧＡ）形成团簇的原理，提出了蒸发－气体－聚集（ＥＧＡ）共沉积方法，并在方华膜载网上成功地制备了Ｆｅ－Ｃｕ纳米磁性包理团簇样品。ＴＥＭ／ＥＤ分析表明，样品中Ｆｅ团簇被Ｃｕ原子所包裹，形成了以Ｆｅ团簇为芯，Ｃｕ膜为壳的良好的芯－壳式包埋结构。当衬底温度由２５℃变化到２００℃时，样品形貌由弥散状过渡到集团状，直至形成大的块状；其结构也相应的由Ｆｅ－Ｃｕ多晶共存变化为一种不规则的单晶形态。     

Fe—Cu包埋团簇的制备及其微观结构的研究

基于溅射－气体－聚集（ＳＧＡ）形成团簇的原理，提出了蒸发－气体－聚集（ＥＧＡ）共沉积方法，并在方华膜载网上成功地制备了Ｆｅ－Ｃｕ纳米磁性包埋团簇样品。ＴＥＭ／ＥＤ分析表明，样品中Ｆｅ团簇被Ｃｕ原子所包裹，形成了以Ｆｅ团簇为芯，Ｃｕ膜为壳的良好的芯－壳式包埋结构。当衬底温度由２５℃变化到２００℃时，样品形貌由弥散状过渡到集团状，直至形成大的块状；其结构也相应的由Ｆｅ－Ｃｕ多晶共存变化为一种不规则的单     

Fe／Ag复合团簇镶嵌薄膜微观结构和磁性的研究

提出了蒸发－气体－聚集（ＥＧＡ）共沉积制备复合团簇镶嵌薄膜的新方法，并分别在方华膜和单晶Ｓｉ（１１１）衬底上制备了系列Ｆｅ／Ａｇ磁性复合团簇镶嵌薄膜样品，对所制备的样品进行了透射电镜分析，Ｘ射线能谱分析和振动样品磁强计磁性测量。结果表明，样品中Ｆｅ、Ａｇ形成了相分离，为ｆｃｃ结构的Ａｇ和ｂｃｃ结构的Ｆｅ多晶共存形态；对应于不同大小的Ｆｅ团簇样品，与块材相比，Ｆｅ团簇的晶格常数呈现出不同程度的收缩，     

溅射——气体——聚集共沉积法制备金属／金属（介质）复合团簇镶嵌薄膜

提出了溅射－气体－聚集共沉积制备金属／金属（介质）复合团簇镶嵌薄膜的新方法，并利用该方法成功地在方华膜衬底上制备了系列Ｆｅ／Ａｇ及ＣａＦ２复合团簇镶嵌薄膜样品。透射电镜分析结果表明，样品中Ｆｅ（Ｃｕ）团簇都较好地镶嵌于Ａｇ（ＣａＦ２）基质中，其结构为两种材料的多晶共存形态。进一步分析发现，与块材相比，Ｆｅ／Ａｇ样品中Ｆｅ团簇晶格常数呈现出不同程度的收缩，而Ｃｕ／ＣａＦ２样品中Ｃｕ团簇晶格常数则呈现出不同程度的膨胀。运用附加压力的模型对该现象进行了解释。     

纳米金属颗粒－绝缘体膜制备的研究

本文介绍了一台利用磁控溅射产生金属团簇，同时蒸发绝缘介质得到金属颗粒－绝缘体包埋团簇的设备，并利用该设备成功地制备出了Ｃｕ：ＣａＦ２和Ｔｉ：ＣａＦ２等金属颗粒膜。该设备适应性广，可产生几乎所有固体金属和半导体团簇。从而可以得到众多组合的功能膜。包埋在绝缘体中的团簇大小在１０ｎｍ－７０ｎｍ之间，为多晶结构；基质ＣａＦ２也为多晶     

镶嵌在CaF2介质中纳米Cu团簇微观结构的研究

利用磁控溅射产生金属Ｃｕ团簇，同时蒸发ＣａＦ２介质，将Ｃｕ团簇包埋在ＣａＦ２介质中，团簇大小可通过改变溅射气压控制，用ＴＥＭ研究了嵌埋团簇的结构，分析结果表明：Ｃｕ团簇呈三角状多晶结构，团簇大小为１０￣７０ｎｍ，基质ＣａＦ２晶体也为多晶结构，Ｃｕ团簇的晶格常数在包埋状态下发生了膨胀，膨胀率大约在１６％左右。     

Co—Ag嵌埋团族薄膜的磁性研究

用蒸发共沉积方法制备了Ｃｏ－Ａｇ磁性嵌埋团簇薄膜并用透射电子显微镜（ＴＥＭ）、背散射（ＲＢＳ）、交变梯度磁强计等技术对团簇的形貌、结构、粒径和磁性能进行了研究。用此方法制备出的嵌埋团簇分布均匀，粒径大小可控，基本无自聚集效应，而且能够防止氧化；它的磁性能随粒径成规律性变化。     

Cu／CaF2复合团簇镶嵌薄膜的光学性质

利用溅射－气体－聚集－共沉积法，分别在方华膜和光学石英玻璃衬底上制备了Ｃｕ团簇嵌埋在ＣａＦ２介质中的Ｃｕ／ＣａＦ２复合团簇镶嵌薄膜样品。透射电镜分析表明，样品为多晶结构；样品的分光光谱仪测量和光Ｋｅｒｒ响应表明，Ｃｕ金属的表面等离子体共振吸收频率明显依赖于样品中Ｃｕ团簇的大小，随着团簇尺寸的减小，榈共振吸收峰发生红移；并且在吸收峰位附近，表现出较大的第三级非线性系数。     

IBAD薄膜与基体界面的显微结构

采用中能离子束辅助沉积（ＩＢＡＤ）技术，在单晶Ａｌ２Ｏ３（０００１）基片上沉积Ｍｏ膜，在ＧＡＡｓ（００１）基片上合成Ｆｅ１６Ｎ２薄膜，用ＨＲＥＭ等研究了Ｍｏｅａｊｄ－Ａｌ２Ｏ３（０００１），Ｆｅ１６ｎ２膜－ＧａＡｓ（００１）界面的显微结构，结果表明：Ｍｏ膜的晶粒呈细小柱状或纤维状，晶粒平均尺寸约８ｎｍ，Ｆｅ１６Ｎ２薄膜为等轴晶，晶粒平均尺寸约为１０ｎｍ，在Ｍｏ膜－Ａｌ２Ｏ３（０００１）界面及Ｆｅ１     

纳米金属颗粒—绝缘体膜制备的研究

本文介绍了一台利用磁控溅射产生金属团簇，同时蒸发绝缘介质得到金属颗粒－绝缘体包埋团簇的设备，并利用该设备成功地制备出了Ｃｕ：ＣａＦ２和Ｔｉ：ＣａＦ２等金属颗粒膜。该设备适应性广，可产生几乎所有固体金属和半导体团簇。从而可以得到众多组合的功能膜。包埋在绝缘体中的团簇大小在１０ｎｍ－７０ｎｍ之间，为多晶结构；基质ＣａＦ２也为多晶。     

Ag nanotubes and Ag/AgCl electrodes in nanoporous membranes

Miniaturization of the entire experimental setup is a key requirement for widespread application of nanodevices. For nanopore biosensing, integrating electrodes onto the nanopore membrane and controlling the pore length is important for reducing the complexity and improving the sensitivity of the system. Here we present a method to achieve these goals, which relies on electroless plating to produce Ag nanotubes in track-etched polymer nanopore templates. By plating from one side only, we create a conductive nanotube that does not span the full length of the pore, and thus can act as a nanoelectrode located inside the nanopore. To give optimal electrochemical behavior for sensing, we coat the Ag nanotube with a layer of AgCl. We characterize the behavior of this nanoelectrode by measuring its current-voltage response and find that, in most cases, the response is asymmetric. The plated nanopores have initial diameters between 100 and 300?nm, thus a range suitable for detection of viruses.     

High-temperature reliability of sintered microporous Ag on electroplated Ag,Au, and sputtered Ag metallization substrates

Ag sinter joining technology has been used in the advanced power applications to replace conventional soldering technology due to its high temperature stability, along with its excellent electrical and thermal conductivity. In this paper, we report the high-temperature reliability (250 °C for 1000 h) for die-attachment structures using Ag sintering technology on Cu substrates with different top metallization layers (Au and Ag), formed via different deposition processes (electroplating and sputtering). The bonding strength over 40 MPa and high-temperature reliability of sintered Ag on the sputtered Ag surface was the best among the systems studied here. Bonding quality and the bonding fracture behavior of sintered Ag on the different metallization substrates were characterized. Ag–Au solid solution was formed due to metallizaion Au atoms diffused into sintered Ag layer, leading to decreased shear strength under high temperature process. The influence of grain structure on the bonding quality at the interface between sintered Ag and the metallization Ag layers were discussed. It revealed that the grain size and orientation of the top metallization Ag layer influenced the bonding quality. The sintered Ag layer formed by Ag hybrid particles may have a selective orientation of metallization layer on the surface (111) of the Ag crystal. These results will be helpful to understand both technological perspectives for design and the applications of sintered Ag from the viewpoint of high-temperature reliability, as well as the fundamental understanding of its bonding quality mechanism with top metallization layers.     

Multiplexed dot immunoassay using Ag nanocubes,Au/Ag alloy nanoparticles,and Au/Ag nanocages

We report the first application of Ag nanocubes, Au/Ag alloy nanoparticles, and Au/Ag nanocages in a multiplexed dot immunoassay. The assay principle is based on the staining of analyte drops on a nitrocellulose membrane strip by using multicolor nanoparticles conjugated with biospecific probing molecules. Nanoparticles were prepared by a galvanic replacement reaction between the Ag atoms of silver nanocubes and Au ions of tetrachloroauric acid. Depending on the Ag/Au conversion ratio, the particle plasmon resonance was tuned from 450 to 700 nm and the suspension color changed from yellow to blue. The particles of yellow, red, and blue suspensions were functionalized with chicken, rat, and mouse immuno gamma globulin (IgG) molecular probes, respectively. The multiplex capability of the assay was illustrated by a proof-of-concept experiment involving simultaneous one-step determination of target molecules (rabbit anti-chicken, anti-rat, and anti-mouse antibodies) with a mixture of fabricated conjugates. Under naked eye examination, no cross-colored spots or nonspecific bioconjugate adsorption were observed, and the low detection limit was about 20 fmol.      

Induced synthesis and characterisation of Ag and Ag2S assembly nanoparticle chains

A facile and efficient template method was developed for the fabrication of Ag and Ag₂S nanoparticle chains. The morphologies and structures of products were characterised by X-ray powder diffraction and transmission electron microscopy. The result shows that the length of Ag and Ag₂S nanoparticle chains are up to several micrometres. Systematic studies exhibit that the concentration of template (polyacrylamide) reagent, reaction solution and ageing time are important factors on the control synthesis of nanoparticle chains. The possible mechanism for the formation of Ag and Ag₂S nanoparticle chains was also discussed. The physical and chemical properties of the Ag and Ag₂S nanoparticle chains were investigated and their phytotoxicities were also researched for the first time. The phytotoxic result shows that the Ag and Ag₂S nanoparticle chains have obvious inhibition of seed germination.     

Nano-sized Ag rather than single-atom Ag determines CO oxidation activity and stability

Single-atom catalysis recently attracts great attentions,however,whether single atom or their nanoparticle(NP)has the advantage in its intrinsic activity remains under heated debate.Ag/Al₂O₃ is a widely used catalyst for many catalytic reactions,while the effect of Ag particle size on the actity is seldom investigated due to the great difficulty in synthesizing single atom Ag and Ag clusters/particles with different sizes.Herein,we firstly prepared an atomically dispersed Ag/Al₂O₃ catalyst using a nano-sized y-Al₂O₃ as the support,subsequently obtained a series of Ag/Al₂O₃ catalysts with different Ag particle sizes by H₂ reducing single-atom Ag/Al₂O₃ catalyst at various temperatures.The Ag/Al₂O₃ treated at 600℃demonstrated superior CO oxidation performance over single-atom Ag/Al₂O₃ and the Ag/Al₂O₃ treated at 400 and 800℃.Based on experimental data and dpnsity functional theory(DFT)calculation results,we reveal that the larger Ag°particle is beneficial to oxygen activation and improves the valence stability during oxidation reaction,while the aggregation of Ag°particle also accordingly decreases the concentration of surface active sites,hence,there is an optimum Ag0 particle size.Our findings clearly confirm that Ag0nanoparticle has the advantage over single-atom Ag species in its intrinsic activity for CO oxidation.     

Density and Thermal Expansion of Liquid Ag–Cu and Ag–Au Alloys

The densities of liquid Cu–Ag and Ag–Au alloys were measured using the technique of electromagnetic levitation. This technique involves producing shadow images of the sample from which the volume is calculated by an image processing algorithm. The density and thermal expansion of several alloys and the pure elements copper, gold, and silver are measured at temperatures above their melting points. In addition, they were investigated as a function of either the copper or gold concentration. It was found from data analysis that the densities can be derived from a linear combination of the molar volumes of the elements and that thermodynamic excess quantities are negligibly small.     

Flow and fracture of free-standing Ag and Cu thin films and Ag/Cu multilayers

Free-standing polycrystalline films of Ag, Cu and Ag/Cu multilayers were tested in tension using an optical diffraction grating for the measurement of the strain. The yield stress and the rate of work hardening both increase strongly with decreasing layer thickness. These effects combine to raise the stress for ductile fracture up to 700 MPa and to lower the maximum plastic strain.     

Interfacial reactions between liquid Sn3.5Ag0.5Cu solders and Ag substrates

The morphology and growth kinetics of intermetallic compounds (IMCs) formed during the soldering reactions between Sn3.5Ag0.5Cu and Ag substrates at various temperatures ranging from 250 to 350 °C were investigated. The interfacial microstructure was quantified with scanning electron microscopy (SEM) for each processing condition. Experimental results show that the thickness of the scallop-shaped Ag₃Sn IMCs layer increased with increasing soldering time and temperature. Furthermore, Cu₆Sn₅ particle precipitates were observed in the Ag₃Sn IMCs layer around and thus suppressing the Ag₃Sn IMCs layer growth. Furthermore, the large Cu₆Sn₅ IMCs tend to appear in the vicinity of interfacial wicker-Ag₃Sn IMCs. Kinetics analyses showed that growth of the Ag₃Sn intermetallic compound was diffusion controlled. The activation energies for the growth of Ag₃Sn IMCs are calculated to be 66.7 kJ/mol.