Epitaxial carbon was grown by heating ͑0001͒ silicon carbide ͑SiC͒ to high temperatures ͑1450-1600°C͒ in vacuum. A continuous graphene surface layer was formed at temperatures above 1475°C. X-ray photoelectron spectroscopy ͑XPS͒ and scanning tunneling microscopy ͑STM͒ were extensively used to characterize the quality of the few-layer graphene ͑FLG͒ surface. The XPS studies were useful in confirming the graphitic composition and measuring the thickness of the FLG samples. STM studies revealed a wide variety of nanometer-scale features that include sharp carbon-rich ridges, moiré superlattices, one-dimensional line defects, and grain boundaries. By imaging these features with atomic-scale resolution, considerable insight into the growth mechanisms of FLG on the carbon face of SiC is obtained.

Epitaxial graphene films examined were formed on the Si-face of semi-insulating 4H-SiC substrates by a high temperature sublimation process. A high-k gate stack on the epitaxial graphene was realized by inserting a fully oxidized nanometer thin aluminum film as a seeding layer, followed by an atomic-layer deposition process. The electrical properties of epitaxial graphene films are retained after gate stack formation without significant degradation. At low temperatures, the quantum-Hall effect in Hall resistance is observed along with pronounced Shubnikov-de Haas oscillations in diagonal magneto-resistance of gated epitaxial graphene on SiC (0001).

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Graphene is created through thermal decomposition of the Si face of 4H-SiC in high-vacuum. Growth temperature and time are varied independently to gain a better understanding of how surface features and morphology affect graphene formation. Growth mechanisms of graphene are studied by ex situ atomic force microscopy ͑AFM͒ and scanning tunneling microscopy ͑STM͒. On the route toward a continuous graphene film, various growth features, such as macroscale step bunching, terrace pits, and fingers, are found and analyzed. Topographic and phase AFM analysis demonstrates how surface morphology changes with experimental conditions. Step-bunched terraces and terrace pits show a strong preference for eroding along the ͕1120͖ planes. Data from AFM are corroborated with STM to determine the surface structure of the growth features. It is shown that elevated finger structures are SiC while the depressed interdigitated areas between the fingers are comprised of at least a monolayer of graphene. Graphene formation at the bottom of terrace pits shows a dependence on pit depth. These features lend support for a stoichiometric view of graphene formation based on the number of decomposing SiC bilayers.