磁性NiO纳米环的气泡模板法制备及气泡多级破裂机制的研究

发布时间：2018-06-25 11:06

本文选题：NiO + 气泡　；参考：《天津理工大学》2011年硕士论文

【摘要】：环状纳米结构是一种很有潜力的纳米器件单元,它在电子学、光学、光电子学、信息存储、生物探测等方面具有潜在的应用价值。对于环状纳米结构的研究,首先就是解决如何能够大面积、低成本地制备出几何形状规则的纳米环的问题。目前,纳米环的制备方法主要有模板刻蚀法、液相化学法、分子束外延法,这些方法存在着实验过程复杂、实验条件苛刻、需要高端昂贵的设备等不便之处。本文中,我们进一步发展了气泡模板法,这种方法的优点是低成本,操作简单而且能够大面积制备NiO纳米环。在这种方法中,气泡通过多级破裂至纳米气泡,纳米气泡起到了模板的作用。 NiO纳米环的制备流程为:首先,配制含有硝酸镍的SiO_2溶胶;其次,采用浸渍提拉法在玻璃衬底或者硅衬底上形成Ni(NO_3)_2/SiO_2薄膜,最后经过热处理得到NiO纳米环。利用扫描电子显微镜(SEM)和X射线衍射仪(XRD)对所制备的样品进行形貌与晶体结构表征,SEM结果显示NiO纳米环的结构完整,分布均匀,排列紧密,平均外直径约为100~150 nm,环壁厚大约10~20 nm,纳米环之间的平均距离约为200-300 nm。XRD结果表明所得到的产物为面心立方晶体结构的NiO。研究了溶胶中各物质的比例、硝酸镍浓度、热处理方式等对NiO纳米环产生影响的因素,获得了大面积制备形状规则的纳米环的最优实验条件。初步研究了NiO纳米环的室温磁性能,结果显示在室温下NiO纳米环具有弱的铁磁性,矫顽力大约为670 Oe,剩余磁化强度约为8.1×10~(-4) emu/cm~2。根据实验过程的中间产物,液滴和分裂的气泡,提出了气泡模板法制备纳米环的形成机制,即熔化了的硝酸镍液滴先分散在多孔的SiO_2薄膜内,然后渗透至薄膜表面;在热处理过程中,产生气体产物,液滴变成气泡,随化学反应的进行不断分裂出新的小气泡,直至反应终止。小气泡的不稳定性最终使其破裂成为纳米环。
[Abstract]:Annular nanostructures are potential nanodevice units, which have potential applications in electronics, optoelectronics, information storage, biological detection and so on. The first step in the research of annular nanostructures is to solve the problem of how to fabricate nanospheres with regular geometry in large area and low cost. At present, the preparation methods of nanometers mainly include template etching, liquid phase chemistry and molecular beam epitaxy. These methods have many disadvantages, such as complicated experimental process, harsh experimental conditions and high cost equipment. In this paper, we further develop the bubble template method, which has the advantages of low cost, simple operation and large area preparation of nio nanorings. In this method, the bubble is broken to the nanometer bubble through multistage, and the nanometer bubble acts as a template. The preparation process of nio nanocyclic is as follows: first, the preparation of SiO2 sol containing nickel nitrate; secondly, Ni (no _ s _ 3) _ 2 / Sio _ (2) thin films were formed on glass or silicon substrates by impregnation Czochralski method. Finally, nio nanospheres were obtained by heat treatment. Scanning electron microscopy (SEM) and X-ray diffractometer (XRD) were used to characterize the morphology and crystal structure of the samples. The average outer diameter is about 100 ~ 150 nm, the thickness of the ring is about 10 ~ 20 nm, and the average distance between the nanospheres is about 200-300 nm 路XRD. The results show that the product is a face centered cubic crystal structure nio. The influence factors of the ratio of various substances in the sol, the concentration of nickel nitrate and the heat treatment method on the nio nanospheres were studied. The optimum experimental conditions for the preparation of regular nano-rings in a large area were obtained. The magnetic properties of nio nanospheres at room temperature have been studied. The results show that the ring has weak ferromagnetism at room temperature, the coercivity is about 670 Oe, and the residual magnetization is about 8.1 脳 10 ~ (-4) emu / cm ~ (2). According to the intermediate product of the experimental process, droplets and split bubbles, the formation mechanism of nano-rings prepared by bubble template method is proposed. The molten nickel nitrate droplets are dispersed in porous SiO2 thin films and then permeated to the surface of the films. In the process of heat treatment, gas products are produced, droplets become bubbles, and new small bubbles are split up with the chemical reaction until the reaction terminates. The instability of small bubbles eventually makes them break up into nanospheres.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TB383.1

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