二维层状结构的CVD生长、掺杂及性能研究
发布时间：2018-10-24 19:00
【摘要】：相比于传统的块体材料,低维纳米材料和纳米结构表现出独特的电学、光学、磁学等物理性能,因而具有重要的应用价值。近年来的研究表明,以石墨烯为代表的二维层装材料具有优异的物理和化学性能,在半导体、电子器件、能源储存与转化方面已初步显示出良好的社会价值和经济效益。与此同时,要实现大规模的工业级二维材料的规模化仍需要很多的努力,其中样品的可控制备是应用的基础。以石墨烯为例,目前多数的制备工艺是需要高温条件下进行,但是高温的合成条件大大限制了石墨烯与半导体工业相结合,因此开发低温条件石墨烯薄膜的合成具有重要意义。此外,层状六方氮化硼和半导体类的二维材料是对半金属性石墨烯的有力补充,初步的研究己经证实前者对于石墨烯等材料电学性能的提升有显著的作用,而后者对于开发出光电探测器、太阳能电池、显示等领域将有巨大应用潜力。然而,当前这两类材料的合成的可控性并不好,结果具有极大的随机性,阻碍了二维异质结等纳米复合结构的进一步应用。针对这些二维材料合成的问题,我们选取半金属类石墨烯、绝缘体六方氮化硼、拓扑绝缘体和半导体二硫化钨为研究对象,通过化学气相沉积法,对这几种二维材料进行了可控合成、结构表征、物性测量以及初步的应用探究,相关研究结果有望对于低维纳米材料的有效合成和规模应用提供有益的参考。本论文主要取得的研究结果包括以下三个方面:1.利用化学气相沉积法在氟金云母、硅/二氧化硅等基底上合成出具有层状结构的高质量三元拓扑绝缘铋硒碲单晶纳米片(Bi2Se3xTe3(1-x))。通过调节硒掺杂的浓度实现了Bi2Se3xTe3(1-x 微观结构的调制,利用拉曼光谱对不同硒掺杂的样品进行了探索。研究结果发现随着硒掺杂量的提高,合成出的Bi2Se3xTe3(1-x)纳米片的拉曼特征峰的位置会向高频方向移动,并表现出不连续变化特征。此研究结果对于合成高质量的拓扑绝缘体及其物性探索具有参考价值。2.利用常压低温化学气相沉积法合成出超薄的大面积石墨烯薄膜(graphene films).在温度低至500℃时,通过调整实验参数在铜箔和覆盖有100nm铜的玻璃基板上均实现了厚度为2-5nm石墨烯膜的生长。研究结果表明,低温合成出的石墨烯膜在400-700nm透光性超过90%,并且具有较好的方块电阻值。此方法为直接在半导体基板上低温生长超薄膜提供了 一种新途径。3.利用化学气相沉积法在硅/二氧化硅基底上合成出高质量的层状半导体硫化钨单晶(WS2)。通过微纳加工工艺,将合成的WS2制备成器件并测试了其传感性能。研究结果发现,WS2器件具有良好的水蒸气响应行为,随着测试环境中水蒸气的含量的增加器件电流明显提高,从而实现了基于WS2的气体湿度传感器。此研究对于二维层状半导体类材料的器件应用具有借鉴意义。
[Abstract]:Compared with traditional bulk materials, low-dimensional nanomaterials and nanostructures exhibit unique physical properties, such as electrical, optical and magnetic properties, so they have important application value. Recent studies have shown that graphene as the representative of two-dimensional laminated materials have excellent physical and chemical properties, in semiconductor, electronic devices, energy storage and conversion has shown a good social value and economic benefits. At the same time, a lot of efforts are needed to realize the large-scale of industrial two-dimensional materials, in which the controlled preparation of samples is the basis of application. Taking graphene as an example, most of the current preparation processes need to be carried out at high temperature, but the synthesis conditions at high temperature greatly limit the combination of graphene and semiconductor industry, so it is of great significance to develop graphene thin films at low temperature. In addition, layered hexagonal boron nitride and semiconductor two-dimensional materials are complementary to semi-metallic graphene. Preliminary studies have shown that the former has a significant effect on the improvement of electrical properties of graphene and other materials. The latter has great potential for development of photodetectors, solar cells, display and other fields. However, the synthesis of these two kinds of materials is not well controlled, and the results are very random, which hinders the further application of two-dimensional heterostructures and other nanocomposite structures. In order to solve the problems in the synthesis of these two-dimensional materials, we choose the semi-metallic graphene, insulator hexagonal boron nitride, topological insulator and semiconductor tungsten disulfide as the research objects, and adopt the chemical vapor deposition method. The controllable synthesis, structure characterization, physical properties measurement and preliminary application of these two dimensional materials have been studied. The results are expected to provide a useful reference for the effective synthesis and scale application of low dimensional nanomaterials. The main results of this paper include the following three aspects: 1. Bi2Se3xTe3 _ (1-x). _ (1-x). Monocrystalline with high quality ternary topological insulating bismuth with layered structure was synthesized on fluorophlogite, silicon / silica substrates by chemical vapor deposition method. The modulation of the microstructure of Bi2Se3xTe3 _ (1-x) was realized by adjusting the concentration of selenium doping, and the samples doped with different selenium were investigated by Raman spectroscopy. The results show that the Raman characteristic peaks of the synthesized Bi2Se3xTe3 _ (1-x) nanocrystals move to the high frequency direction with the increase of selenium doping content and exhibit discontinuous variation characteristics. The results are of reference value for the synthesis of high quality topological insulators and their physical properties. 2. Ultrathin large area graphene film (graphene films). Synthesized by atmospheric pressure and low temperature chemical vapor deposition When the temperature is as low as 500 鈩，
本文编号：2292270
[Abstract]:Compared with traditional bulk materials, low-dimensional nanomaterials and nanostructures exhibit unique physical properties, such as electrical, optical and magnetic properties, so they have important application value. Recent studies have shown that graphene as the representative of two-dimensional laminated materials have excellent physical and chemical properties, in semiconductor, electronic devices, energy storage and conversion has shown a good social value and economic benefits. At the same time, a lot of efforts are needed to realize the large-scale of industrial two-dimensional materials, in which the controlled preparation of samples is the basis of application. Taking graphene as an example, most of the current preparation processes need to be carried out at high temperature, but the synthesis conditions at high temperature greatly limit the combination of graphene and semiconductor industry, so it is of great significance to develop graphene thin films at low temperature. In addition, layered hexagonal boron nitride and semiconductor two-dimensional materials are complementary to semi-metallic graphene. Preliminary studies have shown that the former has a significant effect on the improvement of electrical properties of graphene and other materials. The latter has great potential for development of photodetectors, solar cells, display and other fields. However, the synthesis of these two kinds of materials is not well controlled, and the results are very random, which hinders the further application of two-dimensional heterostructures and other nanocomposite structures. In order to solve the problems in the synthesis of these two-dimensional materials, we choose the semi-metallic graphene, insulator hexagonal boron nitride, topological insulator and semiconductor tungsten disulfide as the research objects, and adopt the chemical vapor deposition method. The controllable synthesis, structure characterization, physical properties measurement and preliminary application of these two dimensional materials have been studied. The results are expected to provide a useful reference for the effective synthesis and scale application of low dimensional nanomaterials. The main results of this paper include the following three aspects: 1. Bi2Se3xTe3 _ (1-x). _ (1-x). Monocrystalline with high quality ternary topological insulating bismuth with layered structure was synthesized on fluorophlogite, silicon / silica substrates by chemical vapor deposition method. The modulation of the microstructure of Bi2Se3xTe3 _ (1-x) was realized by adjusting the concentration of selenium doping, and the samples doped with different selenium were investigated by Raman spectroscopy. The results show that the Raman characteristic peaks of the synthesized Bi2Se3xTe3 _ (1-x) nanocrystals move to the high frequency direction with the increase of selenium doping content and exhibit discontinuous variation characteristics. The results are of reference value for the synthesis of high quality topological insulators and their physical properties. 2. Ultrathin large area graphene film (graphene films). Synthesized by atmospheric pressure and low temperature chemical vapor deposition When the temperature is as low as 500 鈩，
本文编号：2292270
本文链接：https://www.wllwen.com/kejilunwen/cailiaohuaxuelunwen/2292270.html
