Epitaxial Graphene on Silicon Carbide

Presented by Randall Feenstra, Carnegie Mellon University

Graphene (one of more monolayers of graphite) has attracted great interest recently due to its unique electronic properties - linear dispersion at the Fermi-energy, high carrier mobility, ambipolar conduction, and novel magneto transport. Although exfoliation of graphite does produce very high quality graphene layers, such samples are limited in size to 10's or 100's of microns. For large-scale circuits, an alternative means of producing graphene films is needed, and epitaxial formation of graphene on SiC offers one attractive possibility. Graphene forms on SiC simply by heating the wafer to 1300ºC or higher in vacuum, with the silicon preferentially sublimating and the leftover carbon self-assembling into graphene. Differing results are obtained on the two {0001} surfaces of SiC (the Si-face and C-face), revealing certain aspects of the graphene formation process. The evolution of the graphene-on-SiC structure as a function of formation temperature will be described, utilizing data from scanning probe microscopy and from low-energy electron diffraction and microscopy.