Preparation Of Cu-Ag Bimetal Core-shell Nanoparticles And Formation Mechanism Of Ag Shell

The third generation semiconductor materials,represented by Si C and Ga N,have higher bandgap width and thermal conductivity than Si based semiconductor m aterials.The devices made by the third generation semiconductor can operate at higher operating voltage and temperature.The theoretical operating temperature can reach 250 ?,and the traditional interconnection materials such as tin solder can not meet t he requirements of reliable interconnection of the third generation semiconductor devices Nano particl es can be sintered at low temperature,which can provide reliable interconnection for the third generation semiconductor devices under adverse conditions.Cu-Ag bimetallic core-shell nanoparticles have the oxidation resistance of nano silver and the anti electromigration ability of nano copper.The core-shell structure gives full play to the advantages of nano copper and nano silver,and overcomes the disadvantages of nano copper and nano silver,which is a more ideal nano metal sintering interconnection material.However,the coreshell nanoparticles of Cu-Ag bimetal are still faced with the problems of forming uniform and dense silver shell,accelerating the agglomeration of nanoparticles in the coating process,and preparing well dispersed core-shell nanoparticles of Cu-Ag bimetal core-shell nanoparticles.Therefore,a kind of Cu-Ag bimetallic core-shell nanoparticles and its preparation method are proposed in this paper.In this paper,the preparation of nano copper and silver shell coating are separated.Nano copper is used to prepare Cu-Ag bimetallic core-shell nanoparticles by displacement reaction.The core-shell nanoparticles of Cu-Ag bimetallic are directly obtained by displacement reaction of nano copper and silver ions in a controllable system.First of all,nano copper with good appearance and stable output was prepared by liquid-phase reduction method.Furthermore,by controlling the amount of complexing agent,the type of dispersant,the type of dispersant and other experimental parameters,combined with the new rapid pretreatment process of nano copper,a simple and rapid preparation process of Cu-Ag bimetallic core-shell nanoparticles was developed,and Cu-Ag bimetallic core-shell nanoparticles with uniform size,uniform morphology,good dispersion and oxidation resistance were prepared.Furthermore,the mechanism of the effect of different reaction conditions on the growth of silver shell was explored by means of electrochemical analysis.The role of dispersants in the process of silver deposition was studied by means of cyclic voltammetry(CV),chronoamperometry(CA)and linear voltammetry(LSV).The reaction process and deposition kinetics of three dispersants,gelatin,PEG and PVP,were analyzed Furthermore,the reasons for the differences in the morphology and dispersivity of Cu-Ag bimetallic core-shell nanoparticles under different dispersant systems were analyzed.