Paul Maurice Leidinger, Paul Scherrer Institut, Switzerland

Synthesis of supported and freestanding graphene: fundamental understanding of the reaction thermodynamics and kinetics on Cu

Graphene has gone through several stages of popularity since its discovery in 2004, now being extensively used as a well studied substrate material. In this talk, the experimental access to fundamental properties of the 2D material is discussed and the subsequently gained control over the synthesis of graphene layers on copper is presented.

The thermodynamic equilibrium of the graphene formation reaction by chemical vapor deposition (CVD) can be identified by exposing pre-grown graphene flakes to varying reaction conditions, allowing the extraction of the reaction enthalpy and entropy of graphene on copper. By using the determined thermodynamic equilibrium as an anchoring point, it is then possible to systematically analyze the kinetics of the graphene formation reaction. Experimental results and literature reference values were shown to coincide with the predictions from a graphene growth model assuming pre-equilibrated surface Cad species. With the precise knowledge of the graphene thermodynamic equilibrium, special parameter regimes can be targeted leading to surprising graphene growth behaviour.

After synthesis, the post-growth modification and transfer of graphene films from the growth substrate are crucial when targeting certain applications. Based on established transfer mechanisms, new recipes are presented, specifically tailored for the fabrication of ultrathin, vacuum-compatible pressure cells.