ZnO纳米材料的制备及其结构和性质研究

发布时间：2018-06-23 06:43

本文选题：氧化锌 + 纳米材料　；参考：《江南大学》2015年硕士论文

【摘要】：近年来,由于在短波长发光器件、微电子器件、生物传感器、光探测器和光催化剂等方面具有广阔的应用前景,宽禁带半导体材料已成为电子、材料、物理、化学和生物医学等领域的热点研究方向。作为一种具备较大激子束缚能(~60 me V)和室温禁带宽度(~3.37 e V)的宽禁带直接带隙半导体,氧化锌(Zn O)在纳米电子器件、传感器以及发光器件领域有着巨大的发展潜力。此外,Zn O纳米材料表现了出了与其体材料有明显差异的光学、电学、磁学等物理性质。国内外研究人员对Zn O纳米材料的制备和生长机理展开了较广泛的研究,制备了多种具有不同形貌的Zn O纳米材料。本论文主要采用化学气相沉积(CVD)技术,通过改变缓冲层种类、源材料配比和温度等参数,成功制备了一系列具有不同形貌的Zn O纳米材料。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、高分辨透射电子显微镜(HRTEM)、选区电子衍射(SAED)、能量色散谱(EDS)、光致发光(PL)、阴极发光(CL)、X射线光电子谱(XPS)及拉曼(Raman)散射等分析表征手段,对制备的Zn O纳米材料的结构、成分、形貌及发光特性进行了研究,并讨论了不同纳米结构的生长机理。主要研究内容及结果归纳如下。1.四足状Zn O纳米材料利用CVD技术在附有Cr2O3、Ni和Au缓冲层的Si衬底上,分别制备了蒺藜状、锥状及天线状的Zn O纳米材料。XRD、SEM和TEM结果表明,三种Zn O材料均具有六方纤锌矿结构,尖锐的XRD衍射峰表明它们具有较高的结晶质量。PL和CL测试显示它们具有良好的光学特性,发现并解释了纳米蒺藜和纳米锥的尖端光斑现象,以及紫外发射峰的蓝移现象和绿光发射峰的红移现象。在三种四足体的尖端并未发现催化粒子,因此它们的形成应该由气-固生长模式主导。在八面孪晶核等模型的基础上提出并讨论了相应的生长机理,指出不同材料缓冲层与衬底间的润湿性和杨氏模量,以及气态反应物浓度、衬底温度是形成不同形貌的原因。2.钟乳石状Zn O纳米棒在附有Ni层的Si衬底上利用CVD技术制备了钟乳石状Zn O纳米棒阵列。XRD结果表明,纤锌矿结构的Zn O纳米棒具有较高的结晶质量,其中出现的一个弱衍射峰可能来自于具有很高催化活性的γ-Ni5Zn21相。扫描透射电子显微镜(STEM)和TEM结果表明,纳米棒的尖端直径和长度分别在100-200 nm和3-5μm之间。在CL测试过程中,纳米棒尖端发现了亮斑,且具有很强的绿光发射特性。在纳米棒顶部发现了不规则形貌的催化粒子,因此它们的形成应该由气-固-固生长模式主导。在气-固-固模式的框架下讨论了生长机理,Ni-Zn合金的催化和Zn的亚氧化物缓冲层在纳米棒生长过程中起到了重要的作用。3.海胆状Zn O纳米材料在Si衬底上利用CVD技术制备了海胆状Zn O纳米材料,结构分析表明样品同样具有六方纤锌矿结构,每个海胆具有一个核和数十条在[0001]方向上择优生长的纳米足。CL谱显示在380 nm有一个紫外发射峰,在521 nm、520 nm和512 nm有三个绿光发射峰。随着纳米足半径的减小,表面态密度变大,Zn浓度降低,O空位数量减少,表面曲率增大,自由激子数量上升,绿光峰发生了从521 nm到512 nm的蓝移。在经典成核理论的框架下讨论了Zn O纳米海胆的生长机理,分析了成核率和纳米足密度与晶核临界尺寸间的关系,探讨了导致Zn O纳米材料形成不同形貌的主要因素。
[Abstract]:In recent years, wide band gap semiconductor materials have become hot topics in the fields of electronics, materials, physics, chemistry and biomedicine, as a kind of large exciton binding energy (~60 me V) and chamber due to its broad application prospects in short wave long luminescence devices, microelectronic devices, biosensors, photodetectors and photocatalysts. The wide band gap semiconductor with wide band gap (~3.37 e V) and Zinc Oxide (Zn O) have great potential in the field of nanoscale electronic devices, sensors and light emitting devices. In addition, Zn O nanomaterials show the physical properties, such as optical, electrical, magnetic, etc., which have obvious differences with their materials. Researchers at home and abroad have been to Zn O nanometers. A variety of Zn O nanomaterials with different morphologies have been prepared. In this paper, a series of Zn O nanomaterials with different morphologies were prepared by chemical vapor deposition (CVD). A series of Zn O nanomaterials with different morphologies were prepared by means of X ray. XRD, scanning electron microscopy (SEM), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), selective electron diffraction (SAED), energy dispersive spectroscopy (EDS), photoluminescence (PL), cathodoluminescence (CL), X ray photoelectron spectroscopy (XPS) and Raman (Raman) scattering, etc., for the preparation of the structure and composition of nanomaterials. The morphology and luminescence characteristics were studied and the growth mechanism of different nanostructures was discussed. The main contents and results were summarized as follows:.1. tetrapod Zn O nanomaterials were prepared by CVD technology on Si substrate with Cr2O3, Ni and Au buffer layers, and the Zn O nanomaterials of Tribulus, cones and antennas were prepared respectively. SEM and results showed that The three Zn O materials all have six square wurtzite structures, and the sharp XRD diffraction peaks show that they have high crystalline mass.PL and CL tests showing that they have good optical properties. The phenomenon of the tip light spots of nanoscale and nanoscale, the blue shift of the ultraviolet emission peak and the red shift of the green emission peak are found and discussed. The formation of the three kinds of tetrapods did not find the catalytic particles, so their formation should be dominated by the gas solid growth model. On the basis of the eight twin core models, the corresponding growth mechanism was put forward and discussed. The wettability and Young's modulus of different material buffer layers and the substrate, as well as the concentration of gaseous reactants, and the substrate temperature are the shape. The.2. stalactite Zn O nanorods have prepared a stalactite Zn O nanorod array on the Si substrate with Ni layer on the Si substrate with Ni layer. The results show that the Zn O nanorods of the zinite structure have higher crystallization quality, and a weak diffraction peak may come from the highly catalytic activity of the gamma -Ni5Zn21 phase. The scanning transmission electron microscopy (STEM) and TEM results show that the tip diameter and length of the nanorods are between 100-200 nm and 3-5 m respectively. During the CL test, the nanorod tip found bright spots and has a strong green emission characteristics. The growth mechanism is dominated by gas solid solid growth mode. Growth mechanism is discussed under the framework of gas solid solid model. Ni-Zn alloy catalysis and Zn suboxide buffer layer play an important role in the growth process of nanorods..3. sea urchin like Zn O nanomaterials are prepared on Si substrate by CVD technology to prepare O nanomaterials of sea urchin like Zn. Structural analysis shows the sample The product also has a six party wurtzite structure. Each sea urchin has a nucleus and dozens of nanoscale.CL spectra in the [0001] direction, showing a UV emission peak at 380 nm, with three green emission peaks at 521 nm, 520 nm and 512 nm. With the decrease of the radius of nanoscale, the density of the surface state becomes larger, the Zn concentration is reduced, and the O vacancy quantity is reduced. Under the framework of classical nucleation theory, the growth mechanism of Zn O nano sea urchin was discussed under the framework of classical nucleation theory, and the relationship between nucleation rate and nanoscale density and critical size of nucleation was analyzed, and the main cause of the formation of different morphology of Zn O nanomaterials was discussed. Prime.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;TQ132.41

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