绝缘衬底上石墨烯的制备及表征

发布时间：2018-02-06 06:07

  本文关键词： 石墨烯 绝缘衬底 热化学气相沉积 快速升温　出处：《昆明理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：石墨烯是由碳原子以sp2杂化连接组成的,自从2004年问世之后,石墨烯因为拥有特异的结构和杰出的物理化学特性,很快便引起了科学界和商业界的高度关注。本文采用热化学气相沉积(CVD)的方法,以甲烷(CH4)作为碳源,氢气(H2)作为反应气体,氩气(Ar)作为运载气体,探究了直接在SiO2/Si和石英衬底上生长石墨烯的工艺,并通过拉曼光谱、扫描电子显微镜、能谱散射光谱和透射电子显微镜等技术手段对获得的石墨烯进行了表征。通过设计对比性实验,研究石墨烯生长过程中升温方式、冷却速率、催化层厚度以及生长时间对其质量和层数的影响,探索制备高质量大面积石墨烯的最佳工艺参数。测试结果表明,当冷却速率很快时,得到的产物的2D峰有明显的分峰现象,可能是石墨；当冷却速率很慢时,在Ni膜的上面和下面都得不到石墨烯。当Ni膜厚度分别为100,200,300 nm时,在Ni膜的上面以及绝缘衬底和Ni膜的界面处都获得了多层或者少数层数的石墨烯,当Ni膜厚度为400 nm时,拉曼表征显示,只在Ni膜的上面获得了石墨烯,在绝缘衬底和Ni膜的界面处没有任何石墨烯的信号。不同的生长时间(5,10,20 min)对石墨烯的生长也会产生影响,当生长时间只有5min时,在绝缘衬底和Ni膜的界面处虽然获得了石墨烯的信号,但是经过四探针测试仪表征发现,得到的石墨烯膜没有电阻,说明当生长时间太短时,石墨烯膜不连续。当生长时间延长至20min时,可以在绝缘衬底和Ni膜的界面处获得连续的石墨烯膜。采用热CVD的方法,通过快速升温的方式,在气体流量和流量比为H2/CH4 =20/5sccm、生长温度为950℃、生长时间为20min、催化层Ni膜300nm以及快速冷却的条件下,在SiO2/Si衬底和石英衬底上获得了高质量的单层石墨烯。
[Abstract]:Graphene is composed of carbon atoms connected by sp2 hybrids. Since its inception in 2004, graphene has been characterized by its unique structure and outstanding physical and chemical properties. In this paper, the method of thermochemical vapor deposition (CVD), methane (CH4) as carbon source, hydrogen (H2) as reaction gas. Ar as a carrier gas, the growth process of graphene on SiO2/Si and quartz substrates was investigated. Raman spectra and scanning electron microscopy (SEM) were used. The graphene was characterized by energy dispersive spectroscopy and transmission electron microscope. The temperature rise and cooling rate during the growth of graphene were studied by designing comparative experiments. The effects of the thickness of catalyst layer and growth time on the quality and number of layers were investigated to explore the optimum process parameters for the preparation of high quality and large area graphene. The results showed that the cooling rate was very fast. The 2D peak of the obtained product has obvious peak splitting phenomenon, which may be graphite. When the cooling rate is very slow, graphene can not be obtained at the top and bottom of the Ni film, and when the thickness of the Ni film is 100,200,300 nm, respectively. Several layers or a few layers of graphene were obtained on the top of the Ni film and at the interface between the insulating substrate and the Ni film. When the thickness of the Ni film is 400 nm, the Raman characterization shows that. Graphene was obtained only on the top of the Ni film, and there was no signal of graphene at the interface between the insulating substrate and the Ni film. When the growth time was only 5 min, the signal of graphene was obtained at the interface between the insulating substrate and the Ni film. However, it was found that the graphene film had no resistance, which indicated that the graphene film was discontinuous when the growth time was too short, and when the growth time was extended to 20 min. A continuous graphene film can be obtained at the interface between the insulating substrate and the Ni film. The thermal CVD method is used to increase the temperature rapidly. Under the conditions of gas flow and flow ratio of H _ 2 / Ch _ 4 20 / 5 sccm, growth temperature 950 鈩，

本文编号：1493768