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Thermally induced growth of graphene on the two polar surfaces of 6H-SiC is investigated with emphasis on the initial stages of growth and interface structure. The experimental methods employed are angle-resolved valence band photoelectron spectroscopy, soft x-ray induced core-level spectroscopy, and low-energy electron diffraction. On the Si-terminated ͑0001͒ surface, the ͑6 ͱ 3 ϫ 6 ͱ 3͒R30°reconstruction is the precursor of the growth of graphene and it persists at the interface upon the growth of few layer graphene ͑FLG͒. The ͑6 ͱ 3 ϫ 6 ͱ 3͒R30°structure is a carbon layer with graphene-like atomic arrangement covalently bonded to the substrate where it is responsible for the azimuthal ordering of FLG on SiC͑0001͒. In contrast, the interaction between graphene and the C-terminated ͑0001͒ surface is much weaker, which accounts for the low degree of order of FLG on this surface. A model for the growth of FLG on SiC͕0001͖ is developed, wherein each new graphene layer is formed at the bottom of the existing stack rather than on its top. This model yields, in conjunction with the differences in the interfacial bonding strength, a natural explanation for the different degrees of azimuthal order observed for FLG on the two surfaces.

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We have studied friction and dissipation in single and bilayer graphene films grown epitaxially on SiC. The friction on SiC is greatly reduced by a single layer of graphene and reduced by another factor of 2 on bilayer graphene. The friction contrast between single and bilayer graphene arises from a dramatic difference in electron-phonon coupling, which we discovered by means of angle-resolved photoemission spectroscopy. Bilayer graphene as a lubricant outperforms even graphite due to reduced adhesion.

Photoemission spectroscopy is commonly applied to study the band structure of solids by measuring the kinetic energy versus angular distribution of the photoemitted electrons. Here, we apply this experimental technique to characterize discrete orbitals of large pi-conjugated molecules. By measuring the photoemission intensity from a constant initial-state energy over a hemispherical region, we generate reciprocal space maps of the emitting orbital density. We demonstrate that the real-space electron distribution of molecular orbitals in both a crystalline pentacene film and a chemisorbed p-sexiphenyl monolayer can be obtained from a simple Fourier transform of the measurement data. The results are in good agreement with density functional calculations.