▎ 摘　　要

Monolayer graphene has been grown on polycrystalline Ru thin films on SiO(2)/Si substrates. The Ru films have columnar structure with strongly aligned grains exposing flat (0001) surface facets. Adjacent grains show small relative tilts of their (0001) axes and variations in in-plane orientation. Graphene layers grown on this template cover the entire surface and have uniform monolayer thickness. Analysis of the graphene/Ru moire structure shows that monocrystalline graphene domains are coherent across a large number of substrate grains. Hence, the size of monolayer graphene domains is not limited by grain boundaries in the metal template. (C) 2009 American Institute of Physics. [doi:10.1063/1.3224913]