Copper foil is the most promising catalyst for the synthesis of large-area, high-quality monolayer graphene. Experimentally, it has been found that the Cu substrate is semi-molten at graphene growth temperatures. In this study, based on a self-developed C–Cu empirical potential and density functional theory (DFT) methods, we performed systematic molecular dynamics simulations to explore the stability of graphene nanostructures, i.e., carbon nanoclusters and graphene nanoribbons, on semi-molten Cu substrates. Many atomic details observed in the classical MD simulations agree well with those seen in DFT-MD simulations, confirming the high accuracy of the C–Cu potential. Depending on the size of the graphene island, two different sunken-modes are observed: (i) graphene island sinks into the first layer of the metal substrate and (ii) many metal atoms surround the graphene island. Further study reveals that the sinking graphene leads to the unidirectional alignment and seamless stitching of the graphene islands, which explains the growth of large single-crystal graphene on Cu foil. This study deepens our physical insights into the CVD growth of graphene on semi-molten Cu substrate with multiple experimental mysteries well explained and provides theoretic references for the controlled synthesis of large-area single-crystalline monolayer graphene.

铜箔是合成大面积，高质量单层石墨烯的最有希望的催化剂。通过实验，已经发现Cu衬底在石墨烯生长温度下是半熔融的。在这项研究中，基于自行开发的C-Cu经验电势和密度泛函理论（DFT）方法，我们进行了系统的分子动力学模拟，以探索石墨烯纳米结构（即碳纳米团簇和石墨烯纳米带）在半熔融状态下的稳定性。铜基板。经典MD模拟中观察到的许多原子细节与DFT-MD模拟中观察到的原子细节非常吻合，证实了C-Cu电势的高精度。根据石墨烯岛的大小，观察到两种不同的下陷模式：（i）石墨烯岛沉入金属基板的第一层中，并且（ii）许多金属原子围绕石墨烯岛。进一步的研究表明，下沉的石墨烯导致石墨烯岛的单向排列和无缝缝合，这解释了大的单晶石墨烯在铜箔上的生长。这项研究加深了我们对石墨在半熔融Cu衬底上CVD生长的物理认识，并充分解释了多个实验谜团，并为大面积单晶单层石墨烯的受控合成提供了理论参考。