Purine on graphene: PES and NEXAFS study of a heterocyclic aromatic organic compound

We have investigated the properties of a self-assembled purine (C5H4N4) monolayer on epitaxial graphene (EG) on SiC by using high resolution X-ray photoemission spectroscopy (HRPES) and near-edge X-ray absorption of fine structure (NEXAFS). The monolayer of purine on graphene was prepared inside a UHV chamber. The spontaneously-assembled monolayer of purine molecules were oriented parallel to the surface of the monolayer graphene, and it reaches a charge equilibrium state on the monolayer graphene.