Silicon-carbon bond inversions driven by 60 keV electrons in graphene
Toma Susi, Jani Kotakoski, Demie Kepaptsoglou, Clemens Mangler, Tracy C. Lovejoy, Ondrej L. Krivanek, Recep Zan, Ursel Bangert, Paola Ayala, Jannik C. Meyer, Quentin Ramasse
We demonstrate that 60 keV electron irradiation drives the diffusion of threefold coordinated Si dopants in graphene by one lattice site at a time. First principles simulations reveal that each step is caused by an electron impact on a C atom next to the dopant. Although the atomic motion happens below our experimental time resolution, stochastic analysis of 38 such lattice jumps reveals a probability for their occurrence in a good agreement with the simulations. Conversions from three- to fourfold coordinated dopant structures and the subsequent reverse process are significantly less likely than the direct bond inversion. Our results thus provide a model of non-destructive and atomically precise structural modification and detection for two-dimensional materials.
Influence of a graphene substrate on the stabilization of molecular systems with hydrogen bonds
N.N. Semenov Federal Research Center for Chemical Physics of the Russian Academy of Sciences（俄罗斯科学院N.N.谢苗诺夫化学物理联邦研究中心）；Plekhanov Russian University of Economics（普列汉诺夫俄罗斯经济大学）
High-Yield Production and Transfer of Graphene Flakes Obtained by Anodic Bonding
我们报告了通过阳极键合在玻璃上大产量地生产石墨烯薄片。在最佳条件下，我们计数了几十个横向尺寸在20-30 μm左右的薄片和几十个较大尺寸的薄片。60-70%的薄片具有可忽略的D峰。我们表明，这是可能的，很容易转移的薄片楔技术。硅上的转移不会损坏石墨烯并降低掺杂。转移到硅上的薄片的电荷迁移率约为6000 cm ^2/V·s（载流子浓度为10^12 cm^-2），这对于在该衬底上用剥离的石墨烯制备的器件是典型的。
