Fan Xuge, Wagner Stefan, Schädlich Philip, Speck Florian, Kataria Satender, Haraldsson Tommy, Seyller Thomas, Lemme Max C, Niklaus Frank
Department of Micro and Nanosystems, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Osquldas väg 10, 10044 Stockholm, Sweden.
Faculty of Electrical Engineering and Information Technology, Rheinisch-Westfälische Technische Hochschule (RWTH) Aachen University, Otto-Blumenthal-Str. 25, 52074 Aachen, Germany.
Sci Adv. 2018 May 25;4(5):eaar5170. doi: 10.1126/sciadv.aar5170. eCollection 2018 May.
The shape and density of grain boundary defects in graphene strongly influence its electrical, mechanical, and chemical properties. However, it is difficult and elaborate to gain information about the large-area distribution of grain boundary defects in graphene. An approach is presented that allows fast visualization of the large-area distribution of grain boundary-based line defects in chemical vapor deposition graphene after transferring graphene from the original copper substrate to a silicon dioxide surface. The approach is based on exposing graphene to vapor hydrofluoric acid (VHF), causing partial etching of the silicon dioxide underneath the graphene as VHF diffuses through graphene defects. The defects can then be identified using optical microscopy, scanning electron microscopy, or Raman spectroscopy. The methodology enables simple evaluation of the grain sizes in polycrystalline graphene and can therefore be a valuable procedure for optimizing graphene synthesis processes.
石墨烯中晶界缺陷的形状和密度对其电学、力学和化学性质有很大影响。然而，要获取有关石墨烯中晶界缺陷大面积分布的信息既困难又复杂。本文提出了一种方法，该方法可在将化学气相沉积生长的石墨烯从原始铜衬底转移到二氧化硅表面后，快速可视化基于晶界的线缺陷的大面积分布。该方法基于将石墨烯暴露于气态氢氟酸（VHF）中，当VHF通过石墨烯缺陷扩散时，会对石墨烯下方的二氧化硅进行部分蚀刻。然后可以使用光学显微镜、扫描电子显微镜或拉曼光谱来识别这些缺陷。该方法能够简单地评估多晶石墨烯中的晶粒尺寸，因此对于优化石墨烯合成工艺可能是一个有价值的过程。
