Cu基底双层石墨烯的可控制备

Controllable synthesis of bilayer graphene on Cu foils

提出采用改进的化学气相沉积(chenmical vaper deposition,CVD)方法,利用甲烷为碳源在展平的Cu箔表面直接制备双层石墨烯薄膜。通过细致研究甲烷气体流量、生长时间等参数对双层石墨烯成核密度的影响,进一步探讨双层石墨烯生长的机理和条件。研究利用扫描电子显微镜(scanning electron microscope,SEM)、光学显微镜、Raman光谱对石墨烯的表面形貌、结构和堆叠方式进行了表征,提出双层石墨烯的"高效生长时间"为双层石墨烯成核完成后到第1层石墨烯完全覆盖Cu箔之间的时间段。通过优化生长条件,制备出高成核密度(双层与单层石墨烯成核密度比接近0.95)和高覆盖度的双层石墨烯(其中AB堆叠双层石墨烯比例高达82.7%),实现展平Cu薄基底上高覆盖度双层石墨烯的可控制备。

To make bilayer graphene grown directly on Cu foils, improved chemical vapor deposition （CVD） method was applied by using methane as precursor. The impacts of the methane flow rates,growth time on the bilayer graphene nuclei were evaluated to understand the growth mechanism and the key factor to the bilayer graphene synthesis. Scanning electron microscope （SEM）, optical microscopy, and Raman spectroscopy were applied to characterize the morphology and the stacking order of the bilayer graphene. We proposed that the ＂highly effective growth time＂ for bilayer grpahene was between the complete nuclei of the bilay-er graphene and the time that the Cu foil was fully covered by the monolayer graphene. On the basis of these results, bilayer gra-phene with high nucleation density （nuclei density ration of the first and bilayer graphene is about 0. 95） as well as high coverage （bilayer graphene with Bernal stacking ratio up to 82. 7% ） were successfully achieved over the Cu foil.