单晶石墨烯的可控制备及其物性研究

发布时间：2018-06-01 04:13

本文选题：单晶 + 石墨烯　；参考：《宁波大学》2017年硕士论文

【摘要】：石墨烯以其优异的物理和化学性能吸引了人们的广泛关注。在众多石墨烯制备方法中,化学气相沉积法被认为是可规模化制备高品质石墨烯的最佳方法。然而,大多数化学气相法生长的石墨烯薄膜含有多畴结构和高的缺陷等问题,其中晶界及缺陷的存在会严重影响石墨烯的物理特性并使得其器件应用受限。因此,制备大尺寸单晶石墨烯是未来石墨烯器件走向应用的重大挑战。本文针对大尺寸单晶石墨烯的可控生长展开了系统研究,主要工作内容如下:1.大尺寸单晶石墨烯的制备。系统研究了石墨烯单晶形貌及尺寸与生长条件的关联关系,通过调节铜箔的形貌,生长气压,可以得到六角形和花瓣状石墨烯晶畴,并进一步通过降低碳源浓度来抑制成核密度,获得了微米级的单晶石墨烯。在此基础上,进一步研究了局域化制备单晶石墨烯的条件,发现构建铜盒子结构可以有效降低铜箔表面的粗糙程度,抑制石墨烯的成核密度,最终获得大小达5mm的单晶石墨烯。2.单晶石墨烯阵列的制备。设计了一种商业化打印辅助气相沉积生长法,通过在铜箔表面打印富有碳粉的点阵列,在气相沉积过程中制备了石墨烯单晶阵列。系统地研究了不同的碳粉类型、碳粉大小、退火前气氛种类以及生长时间对制备石墨烯阵列的影响,发现制备石墨烯单晶阵列的两个必要条件是:生长前碳粉点的存在以及生长过程中的成核密度小于碳粉点间距。在该条件下成功获得了0.5mm尺寸的单晶石墨烯阵列。3.局部供碳法制备大单晶石墨烯。设计了一种局域化供碳制备设备及工艺,系统研究了不同的生长气压,小孔距离铜箔基底的高度、甲烷浓度、生长时间对铜箔表面石墨烯制备的影响。发现局域化碳源供给可以使得石墨烯在特定范围内生长,进一步分析表明石墨烯圆斑是多晶结构。综上所述,本工作系统研究了石墨烯单晶在不同工艺条件下表面形貌,晶畴尺寸和成核密度的变化,成功发展了一种石墨烯单晶阵列,获得了毫米级单晶石墨烯以及亚毫米级单晶石墨烯阵列,该工作对基于石墨烯电子器件的应用有着重要的意义。
[Abstract]:Graphene has attracted much attention for its excellent physical and chemical properties. Among many graphene preparation methods, chemical vapor deposition (CVD) is considered to be the best way to produce high quality graphene on a large scale. However, most graphene thin films grown by chemical vapor method have many problems such as multi-domain structure and high defects. The existence of grain boundaries and defects will seriously affect the physical properties of graphene and restrict the application of graphene devices. Therefore, the preparation of large size single crystal graphene is a major challenge for graphene devices in the future. The controllable growth of large size single crystal graphene has been studied systematically in this paper. The main work is as follows: 1. Preparation of large-size single-crystal graphene. The relationship between the morphology and size of graphene single crystal and the growth conditions was systematically studied. The hexagonal and petal graphene domains could be obtained by adjusting the morphology of copper foil and the growth pressure. Furthermore, the nucleation density was inhibited by reducing the concentration of carbon source, and micrometer graphene was obtained. On this basis, the conditions of localized preparation of single crystal graphene were further studied. It was found that the construction of copper box structure could effectively reduce the roughness of copper foil surface, suppress the nucleation density of graphene, and finally obtain single crystal graphene. 2 of the size of 5mm. Preparation of single crystal graphene arrays. A commercial print-assisted vapor deposition growth method was designed to prepare graphene single crystal arrays during vapor deposition by printing carbon-rich spot arrays on the surface of copper foil. The effects of different types of carbon powder, size of carbon powder, kinds of atmosphere before annealing and growth time on the preparation of graphene arrays were studied systematically. It is found that two necessary conditions for preparing graphene single crystal arrays are the existence of carbon powder points before growth and the fact that the nucleation density in the growth process is smaller than the distance between carbon powder points. Under this condition, single crystal graphene array. 3 with 0.5mm size was successfully obtained. Large single crystal graphene was prepared by partial carbon supply method. A kind of localized carbon donor preparation equipment and process was designed. The effects of different growth pressures, the height of the pore from the copper foil substrate, the concentration of methane and the growth time on the preparation of graphene on the copper foil surface were systematically studied. It is found that localized carbon supply can make graphene grow in a specific range. Further analysis shows that graphene wafers are polycrystalline. To sum up, the changes of surface morphology, domain size and nucleation density of graphene single crystal under different technological conditions have been systematically studied, and a graphene single crystal array has been successfully developed. Millimeter single crystal graphene and submillimeter single crystal graphene arrays have been obtained. This work is of great significance to the application of graphene based electronic devices.
【学位授予单位】：宁波大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ127.11

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