Epitaxial graphene on metals
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.