Abstract :
[en] Interaction with the substrate strongly affects the electronic/chemical properties of supported graphene. So far, graphene grown by chemical vapor deposition (CVD) on catalytic single crystal transition metal surfaces - mostly 3-fold close-packed - has mainly been studied. Herein, we investigated CVD graphene on a polycrystalline nickel (Ni) substrate, focusing in particular on (100) micrograins and comparing the observed behavior with that on single crystal Ni(100) substrate. The symmetry-mismatch leads to moiré superstructures with stripe-like or rhombic-network morphology, which were characterized by atomically-resolved scanning tunneling microscopy (STM). Density functional theory (DFT) simulations shed light on spatial corrugation and interfacial interactions: depending on the misorientation angle, graphene is either alternately physi- and chemisorbed or uniformly chemisorbed, the interaction being modulated by the (sub)nanometer-sized moiré superstructures. Ni(100) micrograins appear to be a promising substrate to finely tailor the electronic properties of graphene at the nanoscale, with relevant perspective applications in electronics and catalysis.
Funding text :
We acknowledge financial support from Italian Ministry of Foreign Affairs, Directorate General for the Country Promotion (Executive Programme with Argentina 2014–2016 (PGR00190)), from University of Trieste (program “Finanziamento di Ateneo per progetti di ricerca scientifica – FRA 2015”), from Italian Ministry of Education, University and Reasearch through Progetto Strategico NFFA, and from CONICET, FONCyT PICT-2015-2191, SeCyT-UNC (Argentina). Z.Z. acknowledges support by the “ICTP TRIL Programme, Trieste, Italy” in the framework of the agreements with the Elettra and CNR-IOM laboratories. Computational resources have been obtained from CINECA through the ISCRA initiative and the agreement with the University of Trieste and from CCAD, Universidad Nacional de Córdoba (Argentina).
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