Liu Jian, Muíños Henrique Vázquez, Nordlund Kai, Djurabekova Flyura
Helsinki Institute of Physics and Department of Physics, University of Helsinki, POB 43, 00014, Helsinki, Finland. Department of Nuclear Science and Technology, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, People's Republic of China.
J Phys Condens Matter. 2019 Dec 18;31(50):505703. doi: 10.1088/1361-648X/ab4094.
In spite of the versatility of electronic properties of graphene, its fragility and low resistance to damage and external deformations reduce the practical value of this material for many applications. Coating of graphene with a thin layer of hard amorphous carbon is considered as a viable solution to protect the 2D material against accidental scratches and other external damaging impacts. In this study, we investigate the relationship between the deposition condition and quality of diamond-like-carbon (DLC) on top of multilayer graphene by means of molecular dynamics simulations. Deposition of carbon atoms with 70 eV incident energy at 100 K resulted in the highest content of [Formula: see text]-bonded C atoms. An increase of the number of dangling bonds at the interface between the top graphene layer and the DLC film indicates that decrease of the incident energy reduces the adhesion quality of DLC thin film on graphene. Analysis of radial distribution function indicates that [Formula: see text] hybridized carbon atoms tend to grow near already existing [Formula: see text]-atoms. This explains why the quality of the DLC structures grown on graphene have generally a lower content of [Formula: see text] C atoms compared to those grown directly on diamond. Ring analysis further shows that a DLC structure grown on the [Formula: see text]-rich structures like graphene contains a higher fraction of disordered ring structures.
尽管石墨烯具有多种电子特性，但其脆性以及对损伤和外部变形的低抗性降低了这种材料在许多应用中的实用价值。用一层薄的硬非晶碳涂覆石墨烯被认为是保护这种二维材料免受意外刮擦和其他外部损伤影响的可行解决方案。在本研究中，我们通过分子动力学模拟研究了多层石墨烯顶部类金刚石碳（DLC）的沉积条件与质量之间的关系。在100 K下以70 eV入射能量沉积碳原子导致[化学式：见原文]键合碳原子的含量最高。顶层石墨烯层与DLC薄膜界面处悬空键数量的增加表明，入射能量的降低会降低DLC薄膜在石墨烯上的附着质量。径向分布函数分析表明，[化学式：见原文]杂化碳原子倾向于在已有的[化学式：见原文]原子附近生长。这解释了为什么与直接在金刚石上生长的DLC结构相比，在石墨烯上生长的DLC结构中[化学式：见原文]C原子的含量通常较低。环分析进一步表明，在像石墨烯这样富含[化学式：见原文]的结构上生长的DLC结构包含更高比例的无序环结构。
