埋嵌型金属纳米颗粒的应变场研究

发布时间：2018-04-15 15:49

本文选题：纳米颗粒 + 核壳结构　；参考：《江西师范大学》2015年硕士论文

【摘要】：对于埋嵌型的纳米颗粒,在其生长过程中总是不可避免的伴随着应变的产生,这个存在的应变对于纳米颗粒的光学、电学和磁学性能有很大的影响。本文研究了金属纳米颗粒和金属核壳结构纳米颗粒微观形貌与应变场之间的相互关系,研究工作对于金属纳米颗粒以及金属核壳结构纳米颗粒的制备及其潜在应用具有重要的指导意义。1、利用脉冲沉积以及快速退火技术制备了埋嵌再Al2O3薄膜中的Au和Ag纳米颗粒,再用透射电子显微镜观察纳米颗粒的结果。我们用有限元法研究了埋嵌在Al2O3薄膜Au和Ag纳米颗粒的应变场,研究结果发现Au和Ag纳米颗粒均受到Al2O3的非均匀偏应变的作用。而且Au纳米颗粒受到的应变弱于Ag纳米颗粒受到的压缩应变。这可能是由于Au纳米颗粒的杨氏模量大于Ag纳米颗粒的杨氏模量。2、我们应用有限元法进一步研究了Au和Ag纳米颗粒在金属-氧化物-半导体(MOS)存储电容器中的应变。研究结果发现Au和Ag纳米颗粒受到了高介电Al2O3以及传统介电SiO2材料的应变作用,且应变场分布与周边的介电材料密切相关。纳米颗粒埋嵌在不同的介电材料受到的应变有很大的不同。这为我们调控Au和Ag纳米颗粒的微观结构提供了一个有效的手段。3、在以上研究的基础上,研究了不同核尺寸和壳层厚度的埋嵌型Au/Ag以及Ag/Au核壳型结构纳米颗粒应变场。研究发现由于Au的杨氏模量大于Ag的杨氏模量,随着Au/Ag以及Ag/Au核壳结构纳米颗粒核尺寸的增加,Au/Ag核壳结构纳米颗粒的应变梯度也增加,然而Ag/Au核壳结构纳米颗粒的应变梯度保持不变且Au/Ag核壳结构纳米颗粒的应变梯度要大于Ag/Au核壳结构纳米颗粒的应变梯度。随着壳层厚度的增加,虽然Au/Ag和Ag/Au核壳结构纳米颗粒受到的压缩应变都增加,但是其壳的应变梯度却逐渐减小,并且Au/Ag在壳上的应变梯度减小的速度比Ag/Au核壳结构纳米颗粒上减小的速度更大。研究工作对于通过调节形貌来调节Au/Ag和Ag/Au核壳结构纳米颗粒的应变场,进而调节Au/Ag和Ag/Au核壳结构纳米颗粒的微观结构和物理性能具有重要的指导意义。
[Abstract]:For embedded nanocrystalline particles, it is inevitable to produce strain in the growth process, which has great influence on the optical, electrical and magnetic properties of nanoparticles.In this paper, the relationship between the microstructure and strain field of metal nanoparticles and core-shell structure nanoparticles has been studied.The research work has important guiding significance for the preparation and potential application of metal nanoparticles and core-shell structure nanoparticles. Au and Ag nanoparticles embedded in Al2O3 films were prepared by pulse deposition and rapid annealing.The results of the nanoparticles were observed by transmission electron microscope (TEM).The strain field of au and Ag nanoparticles embedded in Al2O3 thin films is studied by finite element method. It is found that both au and Ag nanoparticles are affected by the non-uniform bias strain of Al2O3.The strain of au nanoparticles is weaker than that of Ag nanoparticles.This may be due to the fact that the Young's modulus of au nanoparticles is larger than that of Ag nanoparticles. The strain of au and Ag nanoparticles in metal-oxide-semiconductor storage capacitors is further studied by finite element method.The results show that au and Ag nanoparticles are subjected to the strain action of high dielectric Al2O3 and traditional dielectric SiO2 materials, and the distribution of strain field is closely related to the peripheral dielectric materials.The strain of nanocrystalline embedded in different dielectric materials is very different.This provides an effective means for us to regulate the microstructure of au and Ag nanoparticles. On the basis of the above studies, the strain fields of buried Au/Ag and Ag/Au core-shell nanocrystals with different core sizes and shell thickness are studied.It is found that because the Young's modulus of au is larger than that of Ag, the strain gradient of au / Ag nanoparticles increases with the increase of Au/Ag and Ag/Au core size.However, the strain gradient of Ag/Au core-shell structure nanoparticles remains constant and the strain gradient of Au/Ag core-shell structure nanoparticles is larger than that of Ag/Au core-shell structure nanoparticles.With the increase of shell thickness, the compressive strain of Au/Ag and Ag/Au core-shell nanoparticles increases, but the strain gradient decreases gradually.Moreover, the strain gradient of Au/Ag on the shell decreases faster than that on the Ag/Au core-shell structure nanoparticles.The study has important guiding significance for adjusting the strain field of Au/Ag and Ag/Au core-shell structure nanoparticles by adjusting the morphology, and then regulating the microstructure and physical properties of Au/Ag and Ag/Au core-shell structure nanoparticles.
【学位授予单位】：江西师范大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1

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