Institute for Technical Physics and Materials Science, Centre for Energy Research Konkoly Thege u. 29-33, Budapest, Hungary.
2D Nanoelectronics "Lendület" Research Group, Institute for Technical Physics and Materials Science, Centre for Energy Research , Konkoly Thege u. 29-33, Budapest, Hungary.
Nano Lett. 2015 Dec 9;15(12):8295-9. doi: 10.1021/acs.nanolett.5b03886. Epub 2015 Nov 17.
The adherence of graphene to various crystalline substrates often leads to a periodic out-of-plane modulation of its atomic structure due to the lattice mismatch. While, in principle, convex (protrusion) and concave (depression) superlattice geometries are nearly equivalent, convex superlattices have predominantly been observed for graphene on various metal surfaces. Here we report the STM observation of a graphene superlattice with concave (nanomesh) morphology on Au(111). DFT and molecular dynamics simulations confirm the nanomesh nature of the graphene superlattice on Au(111) and also reveal its potential origin as a surface reconstruction, consisting of the imprinting of the nanomesh morphology into the Au(111) surface. This unusual surface reconstruction can be attributed to the particularly large mobility of the Au atoms on Au(111) surfaces and most probably plays an important role in stabilizing the concave graphene superlattice. We report the simultaneous observation of both convex and concave graphene superlattices on herringbone reconstructed Au(111) excluding the contrast inversion as the origin of the observed concave morphology. The observed graphene nanomesh superlattice can provide an intriguing nanoscale template for self-assembled structures and nanoparticles that cannot be stabilized on other surfaces.
石墨烯在各种晶体衬底上的附着通常会由于晶格失配而导致其原子结构的周期性面外调制。虽然原则上凸（突出）和凹（凹陷）超晶格几何形状几乎是等效的，但在各种金属表面上的石墨烯中主要观察到凸超晶格。在这里，我们报告了在 Au(111)上具有凹（纳米网）形态的石墨烯超晶格的 STM 观察。DFT 和分子动力学模拟证实了 Au(111)上石墨烯超晶格的纳米网形态，并揭示了其作为表面重构的潜在起源，包括纳米网形态在 Au(111)表面上的压印。这种不寻常的表面重构可归因于 Au(111)表面上的 Au 原子特别大的迁移率，并且很可能在稳定凹形石墨烯超晶格中起重要作用。我们报告了在鱼骨形重构的 Au(111)上同时观察到凸和凹石墨烯超晶格，排除了观察到的凹形形态的对比度反转作为其起源。所观察到的石墨烯纳米网超晶格可以为自组装结构和不能在其他表面上稳定的纳米粒子提供一个有趣的纳米级模板。
