金属衬底上石墨烯的控制生长和微观形貌的STM表征

目前化学气相沉积(CVD)方法在不同的金属基底上大规模生长获得石墨烯得到了广泛的应用; 同时扫描隧道显微镜(STM)做为一种强大的精细直观的研究手段可以用于表征金属衬底上石墨烯的微观形貌, 指导石墨烯的控制生长. 本文侧重于Cu箔、Pt 箔和Ni 衬底上石墨烯的控制生长、表面微观形貌、表面缺陷态、堆垛形式的阐述, 得到结论: (1) 两种溶碳量较低的金属(Cu, Pt)上, 石墨烯的生长都符合表面催化的生长机制, 同时层间的范德华相互作用也可以诱导双层石墨烯的生长; (2) 衬底粗糙度的增加可以使石墨烯的电子态去简并化, 从而破坏石墨烯面内π键共轭结构, 导致部分碳原子转变为sp³杂化; (3) 原生的褶皱是由于界面热膨胀系数失配所导致; (4) Pt 箔表面石墨烯的平整度要远优于Cu箔表面的石墨烯, 且不同晶面共存的基底对于石墨烯的连续性并没有产生显著的影响.

Controlled Growth of Graphene on Metal Substrates and STM Characterizations for Microscopic Morphologies

Recently, chemical vapor deposition (CVD) has been widely applied to the large-scale synthesis of graphene on various metal substrates. As a powerful and direct imaging method, scanning tunneling microscopy (STM) has been used to study the microscopic morphologies of graphene on metal substrates, for the purpose of further optimizing the growth parameters. This review presents the recent progress in the controlled growth of graphene on Cu foils, Pt foils, and Ni substrates, as well as the research of the microscopic morphologies, defect states, and stacking orders of graphene. Monolayer growth of graphene on Cu and Pt foils follows a surface catalyzed growth mechanism, while bilayer graphene growth follows an epitaxial growth mechanism. After the formation of a bilayer, the corrugated substrate breaks the planar conjugated π bonds of graphene, inducing a binding configuration change from sp² to sp³. Then, pristine wrinkles are introduced by the thermal expansion mismatch between graphene and the metal substrates. Finally, the roughness of graphene on the Pt foils is considerably less than that of graphene on Cu foils, and the multifaceted interweaving Pt substrate has almost no effect on the in-plane continuity of graphene.