| AVS 61st International Symposium & Exhibition | |
| 2D Materials Focus Topic | Monday Sessions |
| Session 2D+AS+EM+NS+SS-MoA |
| Session: | Dopants, Defects, and Interfaces in 2D Materials |
| Presenter: | Shixuan Du, Chinese Academy of Sciences |
| Authors: | S.X. Du, Chinese Academy of Sciences L.Z. Zhang, Chinese Academy of Sciences W. Hofer, University of Liverpool, UK H.-J. Gao, Chinese Academy of Sciences |
| Correspondent: | Click to Email |
Metal nano-clusters have attracted considerable interest because of the potential applications in catalysis and information storage. Due to the soft nature of epitaxial graphene and the lattice mismatch between graphene and metal substrates periodic moiré patterns can be formed. A graphene/metal template, moiré template, can be used to grow dispersed metal nano-clusters with controllable size and shape, or metal clusters with large size and metal layers. However, how intrinsic properties of metal atoms and the moiré template influence the selective adsorption and the growth mode of metal clusters is still open to debate. A general rule, predicting the morphology of metal nano-clusters on a G/metal surface, important to guide experimenters, is still missing. Using first-principles calculations combined with scanning tunneling microscopy experiments, we investigated the adsorption configurations, electronic structures and the corresponding growth mechanism of several transition metal (TM) atoms (Pt, Ru, Ir, Ti, Pd, Au, Ag, and Cu) on a graphene/Ru(0001) moiré template (G/Ru(0001)) at low coverage. We find that Pt, Ru, Ir, and Ti selectively adsorb on the fcc region of G/Ru(0001) and form ordered dispersed metal nano-clusters. This behavior is due to the unoccupied d orbital of the TM atoms and the strong sp3 hybridization of carbon atoms in the fcc region of G/Ru(0001). Pd, Au, Ag, and Cu form nonselective structures because of the fully occupied d orbital. This mechanism can be extended to metals on a graphene/Rh(111) template. By using Pt as an example, we provide a layer by layer growth path for Pt nano-clusters in the fcc region of the G/Ru(0001). The simulations agree well with the experimental observations. Moreover, they also provide guidance for the selection of suitable metal atoms to form ordered dispersed metal nano-clusters on similar templates.
References:
1. L.Z. Zhang et al. Advanced Materials Interfaces, accepted.
2. Y. Pan et al. Applied Physics Letter, 95, 093106 (2009)