Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University, 637371, Singapore.
ACS Nano. 2011 Jan 25;5(1):147-52. doi: 10.1021/nn101920c. Epub 2010 Dec 20.
In this report, we present Raman spectroscopy investigation of the thermal stability and dynamics of graphene edges. It is found that graphene edges (both armchair and zigzag) are not stable and undergo modifications even at temperature as low as 200 °C. On the basis of polarized Raman results, we provide possible structural models on how graphene edges change during annealing. The zigzag edges rearrange and form armchair segments that are ±30° relative to the edge direction, while armchair edges are dominated by armchair segments even at annealing temperature as high as 500 °C. The modifications of edge structures by thermal annealing (zigzag segments rearrange in form of armchair segments) provide a flexible way to control the electronic properties of graphene and graphene nanostructures.
在本报告中，我们通过拉曼光谱研究了石墨烯边缘的热稳定性和动力学。结果表明，即使在低至 200°C 的温度下，石墨烯边缘（扶手椅型和锯齿型）也不稳定，并且会发生修饰。基于偏振拉曼结果，我们提供了可能的结构模型，说明石墨烯边缘在退火过程中如何发生变化。锯齿边缘重排并形成与边缘方向成 ±30°的扶手椅段，而扶手椅边缘即使在高达 500°C 的退火温度下，也主要由扶手椅段组成。热退火对边缘结构的修饰（锯齿段以扶手椅段的形式重排）为控制石墨烯和石墨烯纳米结构的电子性质提供了一种灵活的方式。
