Fabrication of a Contamination-Free Interface between Graphene and TiO2 Single Crystals

The uniform and seamless interface between graphene and semiconductors, that is, without adsorbates or contamination in between, is of importance for optimizing the electronic and catalytic performances of the combined system. In this work, we try to synthesize graphene directly over atomically flat TiO2 single-crystal surfaces using chemical vapor deposition (CVD) with acetylene as the carbon source. The facile synthetic conditions facilitate the formation of ultrathin polycrystalline graphene films with nanosize domains, while reasonably maintaining the terrace-and-step morphologies of the TiO2 surfaces. The established recipe can thus lead to the construction of a contamination-free interface between graphene and reducible oxides and also provide a well-defined platform for further investigations into the physicochemical properties of the graphene-oxide complex system from an atomic/molecular level.