Ultrafast Transition of Nonuniform Graphene to High-Quality Uniform Monolayer Films on Liquid Cu
Ultrafast Transition of Nonuniform Graphene to High-Quality Uniform Monolayer Films on Liquid Cu
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非均匀石墨烯超快转变为液态铜上的高质量均匀单层薄膜
DOI：
10.1021/acsami.9b01137
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发表时间：
2019
影响因子：
9.5
通讯作者：
Ren Wencai
中科院分区：
文献类型：
--
作者：
Xin Xing;Xu Chuan;Zhang Dingdong;Liu Zhibo;Ma Wei;Qian Xitan;Chen Mao-Lin;Du Jinhong;Cheng Hui-Ming;Ren Wencai
合成具有可控层数的均匀石墨烯薄膜是非常重要的，因为它们的性能很大程度上取决于层数。虽然化学气相沉积（CVD）技术已被广泛应用于大面积石墨烯薄膜的合成，但在固体和液体Cu （L-Cu）上生长的厚度均匀性差，层数多，即使长时间生长也难以形成连续的薄膜。在这里，我们发现最初生长在固体Cu （S-Cu）箔上的非均匀石墨烯薄膜可以在3分钟内迅速转变为连续均匀的单层石墨烯薄膜。制备的薄膜晶粒尺寸更大，质量更高，光学和电学性能更好，在有机发光二极管中的应用性能也比在S-Cu箔上生长的薄膜更好。通过碳同位素标记，我们发现石墨烯在L-Cu上的多层向单层转变经历了蚀刻-“自对准”-聚结过程。这种两步CVD方法不仅为均匀单层石墨烯薄膜的快速生长开辟了一条新途径，而且为其他二维材料均匀单层石墨烯薄膜的可控生长提供了有益的信息，如单层h-BN。
It is essentially important to synthesize uniform graphene films with a controlled number of layers because their properties strongly depend on the number of layers. Although chemical vapor deposition (CVD) on Cu has been widely used to synthesize large-area graphene films, the growth on solid and liquid Cu (L-Cu) suffers from poor thickness uniformity with a great number of adlayers and difficulty in forming continuous films even after a long growth time of hours, respectively. Here, we found that nonuniform graphene films initially grown on solid Cu (S-Cu) foil can rapidly transform into continuously uniform monolayer graphene film on L-Cu within 3 min. Moreover, the films obtained show larger grain size, higher quality, better optical and electrical properties, and better performance in organic light-emitting diode applications than the original films grown on S-Cu foil. By using carbon isotope labeling, we revealed that the multilayer-to-monolayer transition of graphene on L-Cu experiences etching-“self-aligning”-coalescence processes. This two-step CVD method not only opens up a new way for the rapid growth of uniform monolayer graphene films but also provides helpful information for the controlled growth of uniform monolayers of other 2D materials such as monolayer h-BN.