The atomic structure of graphene edges is critical in determining the electrical, magnetic and chemical properties of truncated graphene structures, notably nanoribbons. Unfortunately, graphene edges are typically far from ideal and suffer from atomic-scale defects, structural distortion and unintended chemical functionalization, leading to unpredictable properties. Here we report that graphene edges fabricated by electron beam-initiated mechanical rupture or tearing in high vacuum are clean and largely atomically perfect, oriented in either the armchair or zigzag direction. We demonstrate, via aberration-corrected transmission electron microscopy, reversible and extended pentagon-heptagon (5-7) reconstruction at zigzag edges, and explore experimentally and theoretically the dynamics of the transitions between configuration states. Good theoretical-experimental agreement is found for the flipping rates between 5-7 and 6-6 zigzag edge states. Our study demonstrates that simple ripping is remarkably effective in producing atomically clean, ideal terminations, thus providing a valuable tool for realizing atomically tailored graphene and facilitating meaningful experimental study.
Bibliographical noteFunding Information:
This research was supported in part by the Director, Office of Energy Research, Materials Sciences and Engineering Division, of the US Department of Energy under Contract number DE-AC02-05CH11231, which provided for TEM characterization, including that performed at the National Center for Electron Microscopy, and theoretical modelling; by the Office of Naval Research under MURI Grant N00014-09-1066, which provided for graphene synthesis and suspension; and by the National Science Foundation within the Center of Integrated Nanomechanical Systems, under Grant EEC-0832819, which provided for additional sample characterization and personnel support.
All Science Journal Classification (ASJC) codes
- Biochemistry, Genetics and Molecular Biology(all)
- Physics and Astronomy(all)