【作者】 王科技；

【导师】 陈接胜； 李吉学；

【作者基本信息】 吉林大学 ， 无机化学， 2009， 博士

【摘要】 近年来,准一维纳米材料的研究已成为纳米材料科学领域的前沿和热点。准一维半导体纳米材料由于其独特的物理化学性质,对基础科学研究和纳米结构器件的构筑都具有非常重要的意义,因而引起科学界的高度重视。准一维半导体纳米材料功能化研究的一个重要方面就是探索和发展有效的、易执行的制备技术。本论文根据化学气相沉积的基本原理,设计了低成本、易操作、无污染的真空化学气相反应体系,发展了一条普适的合成半导体纳米材料的新途径。论文在总结吸收文献经验的基础上,选择硫属化合物和硅这两类重要的半导体材料做为研究对象,围绕其一维纳米材料在真空条件下的生长行为、形貌特征以及生长机理展开了系统的研究。这为构筑其他类别的半导体纳米材料提供了一个崭新的思路。本论文的主要研究内容及创新点如下:1、利用真空化学气相反应的方法制备了垂直于平面基底生长的单晶硫化铜纳米盘状结构,为构筑具有特殊形貌的纳米功能器件奠定了理论基础。2、合成了硒化亚铜纳米线,结构研究显示其具有面心立方单晶结构,沿[100]方向优势生长。3、在真空气相反应体系中,合成了规则排布的单晶硅亚微米线阵列。硅线尖端的催化剂粒子证明了它的VLS生长机制,同时也拓展了硫属化合物的应用空间。更多还原

【Abstract】 Recently, research on one-dimensional (1D) nanomaterials has become one of the research frontiers and focuses of the nanomaterials field. 1D semiconductor nanomaterials are of great importance for not only fundamental researches but also the construction of functional nanodevices due to their unique physical-chemical properties. They have attracted great attention and developed rapidly in the past twenty years. An essential problem in 1D nanomaterials researches is to develop the efficient and convenient synthesis techniques. In the other hand, inspecting the native growth mechanism of materials will benefit and direct the synthesis work.Chemical vapor deposition, an important synthesis method for effective synthesis of nanomaterials, was developed very well in resent years. In this thesis, a novel vacuum chemical vapor reaction (CVR) method, which is low-cost, convenient-operated, and environment-friendly, was designed for the synthesis of semiconductor nanomaterials. Various semiconductor materials have been obtained through this method.The two kinds of important semiconductors chalcogenide and silicon were chosen as the study system on the basis of literature. The process of synthesis, morphology characterization and growth mechanism of their nanostructures were investigated in detail. This research is of great importance for the evolution of nano-semiconductor science and technology. The main results presented in the thesis are as follows:1. Synthesis of vertical standing CuS nanoplates on flat substrate via vacuum CVR method. This result provided a theoretic foundation for the fabrication of novel structured nanodevices. The morphology and crystal structure were investigated by SEM and TEM. It was found that the orientation of CuS nanoplate perpendicular to the substrate surface was decided by the native anisotropy characterization of CuS.2. Through the vacuum CVR process, we prepared flexible Cu2Se nanowires with two different structures that are determined by whether to be catalyzed by gold. The nanowires obtained from the sample that was not catalyzed by gold membrane are mono-dispersed with a global particle at the tip of each wire. It is found that the component of wires and the particles are quite different, thus it is concluded that the nanowires were not epitaxially grown from the particles, however, the particles play the roll of catalyst in the reaction which is similar to the solid-liquid-solid process. The growth direction of gold-catalysed nanowires is well oriented, depending on the crystal structure of the growing center of the nanowires. The two kinds of nanowires both have a uniform diameter of about 50 nm and an average length of 50μm. Our research indicates that the nanowires have a single crystal face-center cubic structure. By using the SEM, it is detected that the growth mechanism of the two kinds of nanowires follows different pathways. The preparation of Cu2Se nanowires represents the experimental template for the exploration and application of 1D nanomaterials. The selenide might become an important substitute for the energy transition materials.3. Fabrication of regular oriented single-crystalline silicon sub-micron wire arrays through the CVR method. The existence of Ag2Te particles on the tip of the nanowires indicates the formation of silicon sub-micron wires follows the vapor-liquid-solid growth mechanism. A main difference from the classic VLS mechanism in our experiment is that the vaporous silicon resources were obtained via the prior chemical reaction between silicon substrate and Te vapor at high temperature but not introduced by blowing a Si contianing vapor (such as silane). The results of this study have greatly enriched the VLS growth mechanism and its application, and the vapor reactants of VLS reactions are no longer limited to the gaseous or volatile materials. In addition, the catalyst we choose is Ag2Te, which has not been reported as a catalyst of nanowire growth in literature. So the application of chalcogenides is expanded in the catalytic area.The perfect combination of chalcogenides and silicon nanostructures will bring new properties. It is worth being researched further. One significant characteristic of Ag2Te catalyzing is that it changed the common (111) growth direction of silicon wires, representing a new method of controlled synthesis.更多还原