My main research interest for my graduate studies was to grow graphene on a SiC substrate, to characterize its the physical properties and to modify its surface for more potential applications. For my Ph.D thesis work, I have investigated the temperature dependent structural changes of graphene layers on the SiC substrate, the modification of the gaphene layers using electron beam irradiation, and chemical contrast in imaging upon the graphene layer thickness by using scanning photoemission microscopy. The thesis consists of four chapters. Summaries of each chapter are as follows.
Temperature Dependent Structural Change of Graphene Layers on 6H-SiC(0001) surfaces
We investigated the electronic and structural properties of graphene layers grows on a 6H-SiC(Si-terminated) substrate by using photoemission spectroscopy(PES), low energy electron diffraction (LEED), and near edge X-ray absorption fine structure(NEXAFS). The angle between the plane of the graphene sheet and the SiC substrate was measured by monitoring the variation of the $\pi^*$ transition in the NEXAFS spectrum that has the thickness of the graphene layers. As the thickness of the graphene layers increased, the angle gradually decreased.
Functionalization of multi-layer graphene grown on 6H-SiC(0001) using 1 MeV electron beam irradiation
Graphene layers grown on 6H-SiC(0001) were irradiated with 1MeV electron beam to functionalize its surface. A surface analysis using atomic force microscopy(AFM), the near edge X-ray adsorption fine structure(NEXAFS) spectra of C K-edge and photoemission spectroscopy(PES) suggests that the electron beam irradiation in ambient condition can induce controlled oxidation of the graphene layer without aqueous detergent treatments.
Scanning Photoemission Microscopy of Graphene on $SiO_2$
We successfully recorded scanning photoemission microscopy(SPEM) images of a graphene flake as well as the C 1s core level spectra for the mono-layer and multi-la...