Local transport in graphene nanostructures

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In this proposal graphene will be used as a model system to study electronic transport properties not only in two, but also in one dimension. The goal of this project is to explore the transport properties in graphene nanostructures (GN) grown by self-assembly on SiC-templates of different configurations. Nanostructuring opens the possibility to functionalize the originally gap-less 2D-graphene by introducing electronic gaps and edge states. Electronic transport properties will be systematically studied as a function of ribbon width, geometry, adsorption of dopants including magnetic impurities, intercalates, and as a function of temperature by means of 4-tip STM/SEM in order to elucidate their potential with respect to further functionalization. As recently demonstrated, nanoribbon structures grown on appropriately designed SiC(0001)-MESA structures reveal an exceptional ballistic transport signature with extremely large elastic mean free path lengths (10 mu m at 300K). Using optical lithography, both the width and geometry of the ribbons will be systematically modified. Thus we want to gain controlled access to edge states, band gaps and electronic subbands. The route of processing even allows the growth of large ensembles of identical nanostructures, so that spatially averaging techniques (ARPES, Raman) can be applied to complement STM/STS and local transport data.