Kang Cheong, Jung Da Hee, Lee Jin Seok
Department of Chemistry, Sookmyung Women's University, Seoul 140-742 (Korea) http://fetns.sookmyung.ac.kr.
Chem Asian J. 2015 Mar;10(3):637-41. doi: 10.1002/asia.201403395. Epub 2015 Feb 5.
We report an approach for the synthesis of mono- or bilayer graphene films by atmospheric-pressure chemical vapor deposition that can achieve a low defect density through control over the growth time. Different heating ramp rates were found to lead to variation in the smoothness and grain size of the Cu foil substrate, which directly influenced the density of the graphene domains. The rough Cu surface induced by rapid heating creates a high density of graphene domains in the initial stage, ultimately resulting in a graphene film with a high defect density due to an increased overlap between domains. Conversely, a slow heating rate resulted in a smooth and flat Cu surface, thereby lowering the density of the initial graphene domains and ensuring a uniform monolayer film. From this, we demonstrate that the growth mechanism of graphene on existing graphene films is dependent on the density of the initial graphene domains, which is affected by the heating ramp rate.
我们报道了一种通过常压化学气相沉积法合成单层或双层石墨烯薄膜的方法，该方法可通过控制生长时间实现低缺陷密度。研究发现，不同的加热升温速率会导致铜箔基底的平整度和晶粒尺寸发生变化，这直接影响了石墨烯畴的密度。快速加热导致的粗糙铜表面在初始阶段会产生高密度的石墨烯畴，由于畴之间重叠增加，最终导致石墨烯薄膜具有高缺陷密度。相反，缓慢的加热速率会使铜表面光滑平整，从而降低初始石墨烯畴的密度，并确保形成均匀的单层薄膜。由此，我们证明了石墨烯在现有石墨烯薄膜上的生长机制取决于初始石墨烯畴的密度，而初始石墨烯畴的密度受加热升温速率的影响。
