复合纳米颗粒的应变调控研究

发布时间：2018-08-28 15:50

【摘要】：探索埋嵌型纳米颗粒在应变作用下的微观结构和物理性质变化规律,揭示尺寸、形貌和微观晶格结构之间的内在联系是具有重要科学意义和应用前景的课题。这一课题的研究将有助于人们深入理解形貌和尺寸对纳米颗粒物理化学性质的影响,拓展人们对纳米颗粒材料和应变物理的认识。具体内容如下:(1)在器件应用中,理解纳米颗粒的应变和微观结构之间的物理关系十分重要。在本文中,使用脉冲激光结合快速退火技术将GaAs纳米颗粒埋嵌在Al2O3基体中。揭示了埋嵌型的GaAs纳米颗粒在生长过程中受到了压缩应变。通过应变调控带隙,可以提高和裁剪埋嵌型GaAs纳米颗粒的光学性能,因此可以使PL光谱具有不同的波长。在本文中提出的发现可以用于调控GaAs纳米颗粒的性能以使其在光电子和光子器件中获得潜在的应用。(2)众所周知,面心立方(fcc)结构的Fe在室温环境下是热力学不稳定的。在本文中,我们理论和实验表明在生长过程中,在室温下通过外部应变可以诱导出热力学稳定的fcc结构的Fe纳米颗粒。使用脉冲激光结合快速退火技术在非磁性Al2O3基体中制备出埋嵌型的Fe纳米颗粒。在生长过程中,Fe纳米颗粒受到Al2O3基体的偏应变,而偏应变可以改变Fe纳米颗粒的微观结构并导致在室温下形成热力学稳定的fcc结构的Fe纳米颗粒(空间群为Fm-3m)。第一性原理计算也清楚的表明,fcc结构的应变Fe纳米颗粒在热力学上是稳定的。在磁性测量中,可以观察到Fe纳米颗粒典型的弱相互作用,其特征为超顺磁性和9K的转变温度。(3)使用脉冲激光结合快速退火技术在Al2O3基体中制备出埋嵌型的Au纳米颗粒。在生长过程中,埋嵌型的Au纳米颗粒受到基体的压缩应变。它证实了通过调控埋嵌型Au纳米颗粒的应变和缺陷态,利用氢气钝化处理可以提高和裁剪埋嵌型的Au纳米颗粒的光学性能。研究结果提供了一个有效的方法来提高以贵金属纳米颗粒为基础材料的发射效率,从而使其在光电子和光子器件中获得潜在应用。
[Abstract]:It is of great scientific significance and application prospect to explore the changes of microstructure and physical properties of embedded nanocrystalline particles under strain, and to reveal the internal relations between size, morphology and microstructure of nanocrystalline particles. The study of this subject will help people to understand the influence of morphology and size on the physical and chemical properties of nanoparticles and expand the understanding of nanocrystalline materials and strain physics. The main contents are as follows: (1) in the application of the device, it is very important to understand the physical relationship between the strain and the microstructure of the nanocrystalline particles. In this paper, the GaAs nanoparticles are embedded in the Al2O3 matrix by pulsed laser and rapid annealing. It was revealed that the embedded GaAs nanoparticles were subjected to compression strain during the growth process. The optical properties of embedded GaAs nanoparticles can be improved and clipped by strain-regulating band gap, so that the PL spectra have different wavelengths. The findings in this paper can be used to regulate the properties of GaAs nanoparticles for potential applications in optoelectronic and photonic devices. (2) it is well known that Fe with face-centered cubic (fcc) structure is thermodynamically unstable at room temperature. In this paper, our theoretical and experimental results show that thermodynamically stable Fe nanoparticles with fcc structure can be induced by external strain at room temperature during the growth process. Embedded Fe nanoparticles were prepared by pulsed laser and rapid annealing in nonmagnetic Al2O3 matrix. During the growth process, Fe nanoparticles were subjected to the bias strain of Al2O3 matrix, which could change the microstructure of Fe nanoparticles and lead to the formation of thermodynamically stable Fe nanoparticles with fcc structure (space group Fm-3m) at room temperature. First-principle calculations also show that the strain Fe nanoparticles with FCC structure are thermodynamically stable. In magnetic measurement, typical weak interactions of Fe nanoparticles are observed, which are characterized by superparamagnetism and 9K transition temperature. (3) embedded Au nanoparticles are prepared in Al2O3 matrix by pulsed laser and rapid annealing technique. During the growth process, the embedded Au nanoparticles were subjected to the compression strain of the matrix. It is proved that the optical properties of buried Au nanoparticles can be improved and clipped by hydrogen passivation by regulating the strain and defect state of embedded Au nanoparticles. The results provide an effective method to improve the emission efficiency of noble metal nanoparticles, thus making it a potential application in photoelectron and photonic devices.
【学位授予单位】：江西师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TB383.1

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