Empa, Swiss Federal Laboratories for Materials Science and Technology , Überlandstrasse 129, CH-8600 Dübendorf, Switzerland.
Max Planck Institute for Polymer Research , Ackermannweg 10, D-55128 Mainz, Germany.
Nano Lett. 2017 Apr 12;17(4):2197-2203. doi: 10.1021/acs.nanolett.6b04727. Epub 2017 Mar 21.
The electronic properties of graphene nanoribbons grown on metal substrates are significantly masked by the ones of the supporting metal surface. Here, we introduce a novel approach to access the frontier states of armchair graphene nanoribbons (AGNRs). The in situ intercalation of Si at the AGNR/Au(111) interface through surface alloying suppresses the strong contribution of the Au(111) surface state and allows for an unambiguous determination of the frontier electronic states of both wide and narrow band gap AGNRs. First-principles calculations provide insight into substrate induced screening effects, which result in a width-dependent band gap reduction for substrate-supported AGNRs. The strategy reported here provides a unique opportunity to elucidate the electronic properties of various kinds of graphene nanomaterials supported on metal substrates.
在金属衬底上生长的石墨烯纳米带的电子性质会被衬底表面的性质严重掩盖。在这里，我们引入了一种新方法来研究扶手椅型石墨烯纳米带（AGNRs）的前沿态。通过表面合金化，将 Si 原位插入到 AGNR/Au(111) 界面，抑制了 Au(111)表面态的强烈贡献，从而可以明确确定宽能带和窄能带 AGNRs 的前沿电子态。第一性原理计算提供了对衬底诱导屏蔽效应的深入了解，这导致了衬底支撑的 AGNRs 的带隙随宽度的减小。这里报道的策略为阐明金属衬底上支撑的各种石墨烯纳米材料的电子性质提供了独特的机会。
