纳米氧化铝模板和稀土荧光材料量子点阵的制备

【作者】 杨瑞明；

【导师】 张鹏翔；

【作者基本信息】 昆明理工大学 ， 材料学， 2004， 硕士

【摘要】 模板法制备纳米结构体系是20世纪90年代中期发展起来的一种靠自组装构筑纳米结构体系的新工艺。即在一定的工艺环境(液相或气相)中，直接在模板的微孔内进行纳米结构的原位复制，从原子或分子开始生长纳米结构。且这种纳米结构的物性，可通过改变模板的结构参数进行调制。这种概念上创新的纳米结构制备方法，现在国际上称之为纳米复制(Nano-copy)，这是当今国际热门研究之一，这为设计下一代纳米结构的元器件奠定了基础，具有重要的科学意义和实用价值。 本论文以阳极氧化铝模板(AAO，Anodic Aluminium Oxide)为模板，采用准分子脉冲激光溅射(PLD，Pulse Laser Deposition)法来制备稀土荧光材料的量子点阵。该技术路线是以前未见报道过的，是我们首创的。因此存在一些问题和困难，主要是： (1)氧化铝(AAO)模板的薄膜厚度与孔径的比例要小，以使制备材料能顺利通过氧化铝(AAO)模板到达衬底。但是常用的氧化铝(AAO)模板的长径比高达5000，要使靶材物质穿过这么长的“隧道”到达衬底是很困难的。这就要求我们适当控制长径比。 (2)孔径可控的氧化铝(AAO)模板制备比较困难。要制备尺寸为40～200nm的纳米结构体系、量子点阵均需尺寸可控的AAO模板。 (3)氧化铝(AAO)模板上微孔排列通常是不规则性的。只有微孔排列规则，才能得到规则排列的量子点阵、纳米结构体系。 (4)氧化铝(AAO)模板是一种厚度很薄(仅有几十个微米)的薄膜，虽然有相对高的硬度和耐冲击性，但是比较脆、易碎。 本文综述了当前国际上应用模板纳米结构研究的最新进展，概括了阳极氧化铝模板的产生、发展历史及制备机理模型等，提出我们的方案，比较了一步阳极氧化法、两步阳极氧化法实验结果并，在此基础上总结出我们制备阳极氧化铝(AAO)模板的最佳工艺，获得了尺寸(Φ40～200nm)可精确控制的AAO模板。并以阳极氧化铝模板为掩模板用准分子激光溅射(PLD)制备稀土荧光材料量子点阵的开展研究工作，主要取得了以下成绩： (1)我们开创性地提出了氧化铝模板和准分子脉冲激光溅射结合这一思路，并成功地实现了这一方法，以AAO为掩模板，在MgO单晶衬底上成功地生长了稀土荧光材料Lao.95Euo.o5BaBgol6的量子点阵。实验证明此方法是可行的，这为未来合成其他纳米结构体系材料开辟了一条新的途径。在目前的基础上可以合成发光阵列体系作为显示材料。还可以利用纳米结构体系的新效应、新性能来制作各种功能器件等。这一方法的实现，可以真正做到纳米复制(Nan。一copy)，这是当今国际热门研究之(2)分别采用一步阳极氧化法和两步阳极氧化法制备纳米孔洞尺寸(巾40~ZO0nm)可控的双通氧化铝模板。实验结果表明，要想制备获得高度规则有序的AAO模板，两步阳极氧化法优于一步阳极氧化法。通过摸索制备阳极氧化铝模板(AAO，Anodi。Aluminum oxide)的工艺条件，找到了我们设备下，外加电压对模板有序性(纳米孔径)、氧化时间对模板厚度的影响、pH值对模板有序性的影响关系。(3)用固相反应法制备合成稀土荧光材料，并分别在不同烧结条件下烧结制备PLD溅射用的靶材，找到其最佳烧结工艺条件。(4)对纯度为99.996%的铝箔进行一系列的退火处理，适当的退火使铝箔晶粒长大，消除内应力，对形成规则纳米孔洞结构是有利的。更多还原

【Abstract】 Template-synthesis method is a kind of new technology to preparateof nanostructure system. It carries out in certain environment (liquid or gas phase) by atom’s moving . Therefore nanostructure system can be fabricated. The physical properties of a nano structure material is controlled by changing structure size of the anodic aluminum oxide(AAO) templates. This method has been playing an important role in the fabrication of many kinds of nanostructure system. Recently this method is named Nano-copy. This synthesis method has been attracting more and more attention of the researchers.In this work, matrix of quantum dots of fabricated using AAO template and pulse laser deposition (PLD). The cylindrical pore array structure of AAO serves as a template for the preparation of the quantum dots. This new technical route is initiated by our research group. But there are some difficulties in the experimentation as follows :(1)the proportion of the AAO film thickness and diameter of nano-pores must be small. The proportion produced by normal method is too high about 5000. To make target materials to penetrate such a long "tunnel" is verydifficult.(2)the diameter size of nano-pores must be controlled. So that the quantum dot size can be different.(3) the AAO template should have a structure of highly hexagonal pore array structure.(4)the AAO templates demonstrate some weakness in application, such as, the low mechanical strength and low thermal stability.This thesis has summarized the newest progress of the AAO template application, technology and mechanism. The main results and conclusions can be summarized as follows :(l)we have put forward a new ideal of using the AAO template and PLDsynthesize matrix of quantum dots. And we successfully fabricate the fluorescence material quantum dots on the MgO substrate by this method. With realization of this method, nano-copy really come true. This research is one of international hot issue.(2)the AAO templates with highly ordered hexagonal nano-pores were synthesized by One-Step Anodization method and Two-Step Anodization method . The experiment results show that Two-Step Anodization method is better than One-Step Anodization method. The effects of reaction time , anodize voltage, pH value concentration, temperature have all been studied. Therefore precise hole-size 40~200nm controll has been realized.(3)the rare earth fluorescence material and the target for PLD were synthesized by high temperature solid state reaction .(4)the aluminum foil (99.996%) is annealed under controlled temperatures and duration. So the grain sizes were increased and the stress in the foil was released.更多还原