Arrays of Ru Nanoclusters with Narrow Size Distribution Templated by Monolayer Graphene on Ru
Ru nanoclusters self-assemble over macroscopic sample areas during vapor deposition of Ru on monolayer graphene (MLG) on Ru(0001). The Ru nanoclusters form arrays with a mean lateral cluster diameter of {approx} 20 {angstrom}, cluster heights of 1 or 2 ML, and a size distribution that remains nearly constant with increasing coverage. Combined scanning tunneling microscopy and density functional theory (DFT) show that the clusters are templated by the MLG/Ru(0001) moire unit cell and identify the preferred binding site of the clusters as the low fcc region of the moire. Cross-sectional transmission electron microscopy (TEM) and high-resolution TEM contrast simulations experimentally demonstrate that the interaction of the Ru clusters with the underlying MLG/Ru(0001) leads to a local lifting of the graphene layer of the template. DFT calculations confirm this mechanism of interaction of the Ru clusters with the strongly coupled MLG/Ru(0001). Weakening of the graphene-support coupling via oxygen intercalation is shown to have a major effect on the assembly of Ru nanocluster arrays. With a preferred binding site lacking on decoupled graphene, the Ru nanoclusters grow significantly larger, and clusters with 1 to 4 ML height can coexist.
- Research Organization:
- Brookhaven National Laboratory (BNL) Center for Functional Nanomaterials
- Sponsoring Organization:
- DOE - OFFICE OF SCIENCE
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 1026787
- Report Number(s):
- BNL--93960-2011-JA; KC020401H
- Journal Information:
- Surface Science, Journal Name: Surface Science Journal Issue: 17-18 Vol. 605; ISSN SUSCAS; ISSN 0039-6028
- Country of Publication:
- United States
- Language:
- English
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