Structural Coherency of Graphene on Ir(111)

TLDR

Low‑pressure chemical vapor deposition produces high‑quality monolayer graphene on Ir(111). We quantitatively examined the bending of graphene across Ir step edges. Scanning tunneling microscopy reveals that the CVD‑grown graphene on Ir(111) is continuous over terraces and step edges, contains a very low density of zero‑dimensional edge‑dislocation defects (heptagon‑pentagon pairs linked to small‑angle tilt boundaries), and bends across step edges with a radius of curvature comparable to that of thin single‑wall carbon nanotubes.

Abstract

Low-pressure chemical vapor deposition allows one to grow high structural quality monolayer graphene on Ir(111). Using scanning tunneling microscopy, we show that graphene prepared this way exhibits remarkably large-scale continuity of its carbon rows over terraces and step edges. The graphene layer contains only a very low density of defects. These are zero-dimensional defects, edge dislocation cores consisting of heptagon-pentagon pairs of carbon atom rings, which we relate to small-angle in-plane tilt boundaries in the graphene. We quantitatively examined the bending of graphene across Ir step edges. The corresponding radius of curvature compares to typical radii of thin single-wall carbon nanotubes.