Graphene (an atomic layer of carbon arranged in a honeycomb lattice) may be prepared in epitaxy on metal surfaces. First studies date back to the 1960s:

Very high quality graphene may be prepared on metals. Such samples are well suited to the study of graphene's properties with the help of surface science techniques. In cases when graphene is weakly coupled to its metallic substrate, it is then possible to investigate some of the intrinsic properties of the material. The opposite point of view consists in manipulating the properties of graphene thanks to more or less strong coupling with a metal.

The isolation of graphene on a sacrifical substrate (chemically etched following graphene growth) is known since the 1960s. This approach encounters renewed interest since the last few years, as a route to large area graphene of reasonably good quality. This is of use for fundamental studies (devices are easily prepared this way) as well as for application purposes (transparent conductive electrodes for photovoltaics or displays, or membranes for DNA translocation for instance).

We prepare graphene layers onto various substrates, either single crystals or thin films on wafers, via catalytic thermal decomposition of carbon-containing molecules (usually referred as CVD). We study the growth, structure (for instance, superstructures, cf. simulation of X-ray diffraction data below, or defects), and interaction between graphene and its substrate.

Due to its high stiffness graphene does not adapt the lattice parameter of metals it is grown onto. Moirés result:

The graphene/Ir(111) moiré is a very efficient template for ordered growth of nanosized metallic clusters. We study the structural, magnetic, etc, properties of these objects. Their small size imposes in situ analysis, for example by scanning tunneling microscopy or at synchrotron sources.

Preparing flat metallic layers onto or below graphene is possible as well, either by direct growth of graphene on the metal film, intercalation of the metal layer in between graphene and its substrate, or pulsed laser deposition.

Such systems for instance allow us studying the magnetic properties of the Co-graphene interface, which is considered for new spintronics setups.

Stacking faults and grain boundaries have strong influence on the properties (for instance magnetic anisotropy or electrical conductivity) of thin films, nanowires, and corresponding device.

In the case of metals, we investigate these defects, which develop during epitaxial growth, with the help of surface-sensitive probes (scanning tunneling microscopy, synchrotron sources) and electron microscopy. For homoepitaxy on a fcc(111) surface, we put in evidence the formation of twins along {111} facets which are inclined with respect to the (111) surface, in addition to the well-known [111] twins. The grain boundaries between the different twins have surface traces with heights of 1/3 and 2/3 of an atomic step edge, which are stabilized by annealing.