[u]Strong Field-Effect in Graphene on SiC[/u]

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Graphene, consisting of monolayer thick carbon, can be produced as an isolated layer (exfoliated graphite) or as an epitaxial layer on a SiC(0001) surface. We have used the latter method to produce graphene on 4H-SiC by heating at 1300°C in ultra-high vacuum with in-situ monitoring by electron diffraction. The graphene formation is performed at CMU, while transistor fabrication (with 1.5x0.5 mm2 channel area) is performed at Sarnoff Corp. A strong field-effect is found in the transistors, with mobility of 535 cm2/Vs, exceeding that of prior room temperature studies. Further improvement is likely, by modification of the graphene formation procedure to eliminate surface pits [seen in panel ©] that are believed to form because of residual surface contamination present during the heating.