Epitaxial Graphene on Silicon Carbide Surfaces: Growth, Characterization, Doping and Hydrogen Intercalation

The exceptional electronic properties of graphene, a single atomic layer of bulk graphite, have been theoretically discussed for a long time. In 2004, the discovery of simple ways to produce small graphene samples has led to the realization of its potential for both fundamental physics and applications in nanoelectronics. One of the most promising routes towards a large-scale production of graphene is the graphitization of SiC crystals. The main focus in the present thesis as a multidisciplinary surface science study is directed to the investigation of epitaxially grown graphene on SiC(0001), the Si-terminated basal plane surface of SiC. A few considerations are also devoted to epitaxial graphene on the C-terminated counterpart, SiC(000-1), and to non-basal plane surfaces. Apart from the precise knowledge about the growth conditions and the basic properties of epitaxial graphene, the main results of this thesis concern the successful manipulation of epitaxial graphene on SiC(0001) in terms of technological relevance. On the one hand, surface transfer hole doping allows to compensate the negative charge carriers that are intrinsically present after the graphene growth. On the other hand, the intercalation of hydrogen additionally results in a decoupling from the SiC-substrate and consequently leads to quasi-freestanding graphene on the scale of SiC wafers. This technique sets a new standard in the production of high quality epitaxial graphene.