Wu Siyu, Zhao Wei, Yang Xinliang, Chen Yijun, Wu Wenjie, Song Yenan, Yuan Qinghong
Engineering Research Center for Nanophotonics and Advanced Instrument, Ministry of Education, School of Physics and Electronic Science, East China Normal University, Shanghai 200062, China.
State Key Laboratory of Precision Spectroscopy, School of Physics and Electronic Science, East China Normal University, Shanghai 200062, China.
J Phys Chem Lett. 2019 Sep 5;10(17):4868-4874. doi: 10.1021/acs.jpclett.9b01688. Epub 2019 Aug 13.
In this Letter, we found that the growth of graphene on Cu oxide foil is significantly affected by the concentration of oxygen. The grain size of graphene grown on a Cu substrate with a relatively high oxygen concentration is much smaller than that on the substrate with lower oxygen concentration. By controlling the oxidation of the Cu substrate at a proper degree, we can obtain millimeter scale graphene single crystals at a growth temperature of 1050 °C. On the basis of our experimental observations, the dual role of oxygen in the CVD growth of graphene was revealed: (i) Oxygen on a Cu surface can contribute to the decomposition of hydrocarbon feedstock and decrease the graphene growth barrier, resulting in an increased growth rate and a larger grain size of graphene; (ii) excess oxygen in the Cu substrate leads to etching of the graphene edge. Our research provides insights to obtain large-area and single-crystalline graphene by choosing a proper Cu oxide substrate.
在本信函中，我们发现氧化亚铜箔上石墨烯的生长受到氧浓度的显著影响。在氧浓度相对较高的铜衬底上生长的石墨烯晶粒尺寸远小于在氧浓度较低的衬底上生长的石墨烯。通过将铜衬底的氧化控制在适当程度，我们能够在1050℃的生长温度下获得毫米级的石墨烯单晶。基于我们的实验观察，揭示了氧在石墨烯化学气相沉积（CVD）生长中的双重作用：（i）铜表面的氧有助于烃类原料的分解并降低石墨烯的生长势垒，从而提高石墨烯的生长速率并增大其晶粒尺寸；（ii）铜衬底中过量的氧会导致石墨烯边缘被蚀刻。我们的研究为通过选择合适的氧化亚铜衬底来制备大面积单晶石墨烯提供了思路。
