狄拉克材料的制备、表征及应用研究

发布时间：2018-06-30 05:25

本文选题：狄拉克 + CVD　；参考：《山东师范大学》2016年博士论文

【摘要】：狄拉克材料,是指一类具有特殊能带结构的晶体材料。近几年新涌现的石墨烯与拓扑绝缘体是极具代表性的狄拉克材料。石墨烯作为二维狄拉克材料,是一种由sp2杂化碳原子组成的正六边形呈蜂窝状的平面薄膜,具备诸多独特的物理特性。石墨烯具有优异的电学性质,载流子迁移率极高,约为2×105 cm2/V·s。此外石墨烯还具备优异的光学性质,单层石墨烯在可见光范围内,其光的透过率高达97.7%。石墨烯还具有极大的比表面积,高达2630 m2/g,同时石墨烯具有优良的生物兼容性和很高的亲和性,基于石墨烯的传感器可以有效防止分子变形,并可以富集目标生物分子最终起到信号放大的作用,可应用在表面拉曼增强等传感领域。拓扑绝缘体作为一种区别于导体、半导体及绝缘体的物质形态,这类物质的内部表现为绝缘态,而其表面表现为导电态。由于拓扑绝缘体可控的化学计量比,大的带隙以及超低的损耗,这些独特性质,使其在自旋电子学、光电子器件、量子计算、电化学等领域中存在巨大的应用前景。得益于其独特的能带结构,狄拉克材料展现出了许多优异的物性及其丰富多彩的科学内涵,从而表现了广泛的应用前景,已经成为了国内外最具前沿科学(涉及实验研究和理论研究的众多领域)研究的焦点。本文利用双温区CVD系统在石英基底上实现狄拉克材料石墨烯薄膜的直接制备,讨论生长参数对石墨烯质量的影响。利用CVD法在石英光纤表面制备石墨烯薄膜,为基于石墨烯的光纤激光器及光纤生物传感器做前期准备。将氧化石墨烯与金字塔形硅相复合,制备拉曼增强基底,实现对R6G分子的检测。通过设计实验,生长石墨烯包覆的铜纳米颗粒(G@CuNP)复合拉曼增强基底,研究其拉曼增强特性。利用CVD方法,实现拓扑绝缘体Bi2Se3和层数可控石墨烯的复合,探究工艺参数对Bi2Se3形貌的影响。主要结论如下:(1)设计了独特的双温区CVD生长系统,在绝缘的石英衬底表面实现了高质量且分布均匀的狄拉克材料石墨烯的直接制备。系统的温度梯度直接影响获得的石墨烯的质量,不同位置处石墨烯的生长机理不同。在靠近高温区的位置,铜原子作为成核点捕获碳原子形成石墨烯。在中间低温区,碳原子直接沉积在衬底表面作为成核点。本工作中,分布均匀且含量丰富的铜原子是制备高质量石墨烯不可或缺的关键因素。我们所提供的石墨烯制备工艺为石墨烯的实际应用,特别是在光电子领域的应用,开辟了崭新的途径。(2)提供了一种在光纤表面直接制备均匀狄拉克材料石墨烯的一种气相辅助的cvd生长工艺。我们引入一种气相铜原子辅助cvd工艺来解释光纤表面石墨烯的生长机理。通过调节生长时间,可以控制石墨烯的层数。通过控制生长前h2和ar混合气体的流量,可以对光纤表面的形貌结构进行调节。较大的h2和ar混合气体的流量下,可以在光纤表面获得均匀的石墨烯结构;较小的h2和ar混合气体的流量下,可以在光纤表面获得致密的碳纳米管结构。此项工作提供了一种前景广阔的无转移直接制备基于石墨烯或碳纳米管的光纤可饱和吸收体的方法,对实现稳定的光纤激光锁模输出具有一定的现实指导意义。(3)提供了一种成本低、操作简单的方法制备基于go/ag/3d-si的sers基底。利用r6g作为探测分子证实了我们所制备的基于go/ag/3d-si的sers基底具有良好的生物兼容性、均一性及稳定性。通过设计3d-si、go/3d-si、ag/3d-si和go/aga/3d-si的对比实验进一步表明go薄膜非常易于在3d-si表面合成分布均匀的ag纳米颗粒,进而获得灵敏度高、生物兼容性好、均一性好和稳定性高的sers信号。借助comsol软件,在理论上证实了go/ag/3d-si可作为理想的sers基底。相应的结果表明新奇的go/ag/3d-si基底可作为灵敏度高、前景广泛的sers基底应用在医学、食品安全、生物科学等领域实现分子的检测。(4)提供了一种新颖、操作简单且成本低廉的合成石墨烯@铜纳米颗粒sers基底的思路。利用我们设计的制备方法,可以在g@cu基底表面较为容易的获得g@cunp结构。cunp提供的em增强与石墨烯提供的cm增强结合在一起,提供了g@cunp/g@cu拉曼增强基底的整体增强。而且由于石墨烯可以作为钝化层抑制cunp和cu的表面氧化,因而我们制备的g@cunp/g@cu拉曼增强基底稳定性非常好。相应的sers结果表明全包覆的核壳结构提供了另一种形式的灵敏度高、前景广泛的sers基底应用在医学、食品安全、生物科学等领域实现分子的检测。(5)证明了在g/sio2/si衬底表面直接制备高质量均匀的bi2se3材料的cvd工艺。石墨烯缓冲层、g/sio2/si衬底表面温度、生长时间和气体流量在制备bi2se3材料的过程中起着至关重要的作用。我们详细讨论了上述参数在g/sio2/si衬底表面直接制备高质量均匀的bi2se3材料的影响机理。通过调节相应的参数,我们可以获得bi2se3材料的薄膜和片状结构。这种方法为我们提供了一种前景广阔且经济的bi2se3制备手段,将进一步促进这种材料在实际领域的应用。
[Abstract]:Dirac material is a kind of crystal material with special band structure. In recent years, the newly emerged graphene and topological insulators are representative Dirac materials. As a two-dimensional Dirac material, graphene is a kind of hexagonal plane thin film composed of SP2 hybrid carbon atoms, with a lot of unique physical characteristics. Graphene has excellent electrical properties. The carrier mobility is very high, about 2 x 105 cm2/V. S.. Besides, graphene has excellent optical properties. Monolayer graphene is in the range of visible light, its transmittance is as high as 97.7%. graphene with a maximum specific surface area, up to 2630 m2/g, and excellent biocompatibility of graphene. High affinity, graphene based sensors can effectively prevent molecular deformation, and can enrich the target biomolecules at the end of signal amplification, and can be applied to the surface Raman enhancement sensing field. The topological insulators are used as a material form different from the conductors, semi conductors and insulators, and the interior of such materials. It shows an insulating state and its surface is conducting state. Due to the controlled chemical metering ratio, large band gap and ultra-low loss of the topological insulator, these unique properties make it very promising in the fields of spintronics, optoelectronic devices, quantum computing, electrochemistry, and so on. Thanks to its unique band structure, Dirac material The material shows a lot of excellent physical properties and its rich and colorful scientific connotation, thus showing a wide range of application prospects. It has become the focus of the most frontier science at home and abroad (involving many fields of experimental research and theoretical research). This paper uses the dual temperature region CVD system to implement the Dirac film on the quartz substrate. The effect of growth parameters on the quality of graphene is discussed. The preparation of graphene film on the surface of quartz fiber is prepared by CVD method. The preparation of fiber laser based on graphene and fiber optic biosensor is prepared. The synthesis of graphene oxide and Pyramid silicon phase is used to prepare the Raman enhanced substrate, and the detection of R6G molecules is realized. The experiment was designed to study the Raman enhancement properties of copper nano particles (G@CuNP) composite Raman enhancement substrates coated with graphene. The CVD method was used to realize the combination of topological insulator Bi2Se3 and layer number controlled graphene. The influence of process parameters on the Bi2Se3 morphology was investigated. The main conclusions are as follows: (1) a unique dual temperature region CVD growth system was designed. The direct preparation of high quality and evenly distributed Dirac material is realized on the surface of the insulated quartz substrate. The temperature gradient of the system directly affects the quality of the obtained graphene. The growth mechanism of graphene at different positions is different. In the position near the high temperature zone, the copper atom is captured as the nucleating point to form graphene. In the middle low temperature region, carbon atoms are directly deposited on the surface of the substrate as nucleating points. In this work, the homogeneous and rich copper atom is a key factor in the preparation of high quality graphene. The preparation process of graphene is a new method for the practical application of graphene, especially in the field of photoelectron. (2) a gas assisted CVD growth process is provided for the direct preparation of homogeneous Dirac material graphene on the fiber surface. A gas phase copper atom assisted CVD process is introduced to explain the growth mechanism of graphene on the surface of the fiber. By adjusting the growth time, the number of graphene layers can be controlled. The H2 and a before growth are controlled by controlling the growth time. The flow of R mixed gas can regulate the morphology and structure of the optical fiber surface. The uniform structure of graphene can be obtained on the fiber surface under the flow of the larger H2 and AR mixture. The compact carbon nanotube structure can be obtained on the optical fiber surface under the flow of small H2 and AR mixture. This work provides a broad prospect. The method of optical fiber saturable absorber based on graphene or CNTs is directly prepared by wide free transfer. It has some practical guiding significance to achieve stable optical fiber laser locking output. (3) a low cost and simple operation method for the preparation of SERS base based on go/ag/3d-si is provided. Using R6G as a probe, we confirm that we The go/ag/3d-si based SERS substrate has good biocompatibility, uniformity and stability. The comparative experiments of the design of 3d-si, go/3d-si, ag/3d-si and go/aga/3d-si further indicate that the go film is very easy to synthesize uniform Ag nanoparticles on the surface of 3d-si, and the sensitivity is high, the biocompatibility is good, and the homogeneity is good. Good and high stability SERS signals. With the help of COMSOL software, go/ag/3d-si can be proved to be the ideal SERS base in theory. The corresponding results show that the novel go/ag/3d-si substrate can be used as a highly sensitive and promising SERS base application in the fields of medicine, food safety, biological science and other fields. (4) it provides a new method. The idea of a simple and inexpensive synthetic graphene @ copper nanoparticle SERS substrate. Using our design method, the EM enhancement provided by the g@cunp structure.Cunp can be easily obtained on the surface of the g@cu base, together with the CM enhancement provided by the graphene, and provides the overall enhancement of the g@cunp/g@cu Raman enhanced substrate. Moreover, as graphene can inhibit the surface oxidation of cunp and Cu as a passivation layer, the g@cunp/g@cu Raman enhanced substrate stability is very good. The corresponding SERS results show that the full coated nuclear shell structure provides another form of sensitivity, and the promising SERS substrate is used in medicine, food safety, and biological science. Molecular detection in other fields. (5) the CVD process of direct preparation of high quality bi2se3 materials on the surface of the g/sio2/si substrate is proved. The graphite buffer layer, the surface temperature of the g/sio2/si substrate, the growth time and the gas flow play an important role in the preparation of the bi2se3 material. We discussed the above parameters in g/sio2 The mechanism of the direct preparation of high quality and uniform bi2se3 materials on the surface of the /si substrate. By adjusting the corresponding parameters, we can obtain the thin film and flake structure of the bi2se3 material. This method provides us with a promising and economical means of bi2se3 preparation, which will further promote the application of this material in the practical field.
【学位授予单位】：山东师范大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O613.71

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