In situ photoemission spectroscopy study on formation of HfO2 dielectrics on epitaxial graphene on SiC substrate

High quality HfO2 dielectrics have been grown on epitaxial graphene on 4H-SiC substrates and have been studied by using in situ x-ray photoemission spectroscopy. The in situ thermal treatment shows that the HfO2/graphene/4H-SiC heterojunctions have good thermal stability up to 650 degrees C. A shift of core-level spectra from graphene layer implies that charge transfer takes place at the interface. The high thermal stability and sufficient barrier heights between HfO2 and graphene indicate that high-k dielectric grown on graphene is very promising for the development of graphene-based electronic devices.