Optical and structural characterization of epitaxial graphene on vicinal 6H-SiC(0001)–Si by spectroscopic ellipsometry, Auger spectroscopy, and STM
(Color online) Auger spectrum of graphene grown on an SiC(0001)–Si face, showing the graphitelike line shape of the C–KVV transition.
(Color online) Real- and reciprocal-space images of a 6H-SiC(0001) 3.5° vicinal (√3 × √3)R30° surface. (a) STM topography (I = 0.2 nA, U = −2.0 V) including a line profile across the steps. The periodicity shown at the top was obtained by LEED and arises from ∼10√3 Si atoms per terrace. (b) LEED image showing SiC bulk (1 × 1) and the surface (√3 × √3)R30° periodicities. The close-up details the splitting of one of the spots, here defined as (0). The LEED electron energy is 102 eV.
(Color online) Eighty electron volt LEED pattern of a graphene sample, showing the spot elongation that is characteristic of a stepped surface with no well-defined terrace width.
(Color online) (a) STM topography image of a graphene sample on a 3.5° stepped SiC substrate. The line shows irregular step bunching, which causes the multilayer step heights shown in the line profile (b).
(Color online) Optical functions for epitaxial graphene grown on 6H SiC-(0001): (a) Graphene CRI. (b) Graphene dielectric function. (c) Interface layer CRI. (d) Interface layer dielectric function.
(Color online) Minima obtained in the fitting procedure. The results verify the energy of the UV peak of the interface layer.
(Color online) Results of the analysis for the second epitaxial graphene sample, obtained by holding the CRI values constant.
Article metrics loading...
Full text loading...