Arrays of Ru nanoclusters with narrow size distribution templated by monolayer graphene on Ru

作者：Sutter Eli^*; Albrecht Peter; Wang Bin; Bocquet Marie Laure; Wu Lijun; Zhu Yimei; Sutter Peter

来源：Surface Science, 2011, 605(17-18): 1676-1684.

DOI：10.1016/j.susc.2011.01.026

• Monolayer graphene
• Ru(0001)
• Ru nanoclusters
• Oxygen-intercalated graphene
• Scanning tunneling microscopy
• Transmission electron microscopy

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 similar to 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.

• 出版日期2011-9