AlN和ZnO纳米结构的电弧放电法制备及生长机制研究

发布时间：2018-02-08 16:37

本文关键词： 电弧放电方法 AlN纳米结构四脚ZnO纳米结构生长机制稀磁半导体　出处：《清华大学》2010年博士论文　论文类型：学位论文

【摘要】：AlN和ZnO低维纳米材料和纳米结构因其在未来纳米器件领域具有广阔的应用前景而成为纳米材料制备与合成研究中一个持续的热点,而电弧放电方法在纳米材料制备,尤其是复杂纳米结构的制备研究中表现出很大的潜力。在此前提下,论文系统地研究了AlN纳米材料的电弧放电法制备,并重点探讨了实验中获得的各种纳米结构的生长机制。论文提出了一种采用电弧放电方法制备稀磁半导体纳米材料的新手段,以Al,Co合金铸锭为原料,在电弧放电过程中,使之与氮气直接反应生成Co掺杂的AlN纳米棒和花状纳米棒阵列,并在VLS模式基础上分析了它们的生长机制。其中花状纳米棒阵列在室温和500K的高温下都表现出明显的铁磁性。在大电流的放电过程中,使纯Al块和氮气直接反应,制备了独特的珊瑚状和羽状AlN自组装纳米结构。本文提出了一种基于VS模式的两晶向交替生长机制来解释羽状纳米结构的形成,并利用气固相转变中的枝晶生长现象来理解这种复杂的自组装过程。光致发光测试表明羽状AlN纳米结构具有良好的可见光发光性能。将电弧放电法推广到ZnO纳米结构的制备,通过控制反应气氛中的氧分压,制备了从纳米颗粒到标准四脚纳米结构,再到板根状四脚纳米结构,这一系列形态可控的ZnO纳米材料。提出了一种中心纳米棒生长机制,较好地解释了新颖的板根状四脚ZnO纳米结构的生长。在CVD法制备AlN纳米材料的对照性实验中,通过控制反应条件和催化剂的分散方式,制备出了均匀的AlN纳米线、项链状AlN纳米线和花状AlN纳米线阵列。分析表明,项链结构中纳米颗粒的表面是由h-AlN晶体中的{1011}组合而成;本文采用一种VLS与VS模式相协作的生长机制解释了项链状AlN纳米线的形成。通过两种制备方法产物和生长条件的对比,分析了电弧放电方法的特点。
[Abstract]:AlN and ZnO low-dimensional nanomaterials and nanostructures have become a continuous hot spot in the preparation and synthesis of nanomaterials due to their wide application prospects in the future nanodevices, while arc discharge methods are used in the preparation of nanomaterials. Especially, the preparation of complex nanostructures has great potential. On this premise, the preparation of AlN nanomaterials by arc discharge has been systematically studied, and the growth mechanism of various nanostructures obtained in the experiments has been emphatically discussed. In this paper, a new method of preparing dilute magnetic semiconductor nanomaterials by arc discharge method is proposed. The Al _ (Co) alloy ingot is used as raw material in the process of arc discharge. Co-doped AlN nanorods and flower-like nanorods arrays were synthesized by direct reaction with nitrogen, and their growth mechanism was analyzed on the basis of VLS mode. The flower-like nanorods arrays exhibit obvious ferromagnetism at room temperature and 500K high temperature. In the process of high current discharge, the pure Al block is directly reacted with nitrogen. The unique coral-like and pinnate AlN self-assembled nanostructures were prepared. In this paper, a two-crystal alternating growth mechanism based on vs mode was proposed to explain the formation of pinnate nanostructures. The complex self-assembly process was understood by dendritic growth in gas-solid phase transition. Photoluminescence measurements showed that the pinnate AlN nanostructures had good visible photoluminescence properties. The arc discharge method was extended to the preparation of ZnO nanostructures. By controlling the oxygen partial pressure in the reaction atmosphere, the nanoparticles were prepared from the nanoparticles to the standard tetrapodal nanostructures, and then to the plate root tetrapod nanostructures. A new growth mechanism of central nanorods is proposed, which can explain the growth of novel ZnO nanostructures. In the control experiment of preparing AlN nanowires by CVD method, uniform AlN nanowires, necklace-like AlN nanowires and flower-like AlN nanowires were prepared by controlling the reaction conditions and the dispersion of the catalyst. The surface of the nanoparticles in the necklaces is composed of {1011} in h-AlN crystal. In this paper, the formation of necklace-like AlN nanowires is explained by a growth mechanism of cooperation between VLS and vs mode. The characteristics of arc discharge method are analyzed.
【学位授予单位】：清华大学
【学位级别】：博士
【学位授予年份】：2010
【分类号】：TB383.1

【参考文献】