Department of Electrical Engineering, National TsingHua University, Hsinchu 30013, Taiwan.
Langmuir. 2011 Nov 15;27(22):13748-53. doi: 10.1021/la2022038. Epub 2011 Oct 24.
We report on graphene films grown by atmospheric pressure chemical vapor deposition on bulk and thin film nickel. Carbon precipitation on the polycrystalline grains is controlled by the methane concentration and substrate cooling rate. It is found that graphene grows over multiple grains, with edges terminating along the grain boundaries and with dimensions directly correlated to the size of the underlying grains. This greatly restricts the resulting graphene size (<10 μm) in the thin film growth, whereas monolayer graphene with linear dimensions of hundreds of micrometers takes up the great majority of the surface overlayers on the bulk nickel (>50%). In addition, the number of layers can be better controlled in the bulk growth. Characterizations of the graphene sheets using transmission electron microscopy, Raman spectroscopy, and transport measurements in the field-effect configuration are also discussed.
我们报告了在块状和薄膜镍上通过常压化学气相沉积生长的石墨烯薄膜。碳在多晶颗粒上的沉淀受甲烷浓度和基底冷却速率的控制。研究发现，石墨烯在多个晶粒上生长，边缘沿着晶界终止，其尺寸与下面晶粒的大小直接相关。这极大地限制了薄膜生长中石墨烯的尺寸（<10 μm），而在块状镍上，占据大部分表面覆盖层的是具有数百微米线性尺寸的单层石墨烯（>50%）。此外，在块状生长中可以更好地控制层数。还讨论了使用透射电子显微镜、拉曼光谱和场效应配置中的输运测量对石墨烯片的特性。
