title: Nucleation of epitaxial graphene on SiC(0001).
abstract: A promising route for the synthesis of large-area graphene, suitable for standard device fabrication techniques, is the sublimation of silicon from silicon carbide at elevated temperatures (>1200 degrees C). Previous reports suggest that graphene nucleates along the (110n) plane, known as terrace step edges, on the silicon carbide surface. However, to date, a fundamental understanding of the nucleation of graphene on silicon carbide is lacking. We provide the first direct evidence that nucleation of epitaxial graphene on silicon carbide occurs along the (110n) plane and show that the nucleated graphene quality improves as the synthesis temperature is increased. Additionally, we find that graphene on the (110n) plane can be significantly thicker than its (0001) counterpart and appears not to have a thickness limit. Finally, we find that graphene along the (110n) plane can contain a high density of structural defects, often the result of the underlying substrate, which will undoubtedly degrade the electronic properties of the material. Addressing the presence of non-uniform graphene that may contain structural defects at terrace step edges will be key to the development of a large-scale graphene technology derived from silicon carbide.
authors.affiliation: The Electro-Optics Center, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA. jrobinson@psu.edu
authors.forename: Joshua
authors.initials: J
authors.lastname: Robinson
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Weng
authors.forename: Kathleen
authors.initials: K
authors.lastname: Trumbull
authors.forename: Randall
authors.initials: R
authors.lastname: Cavalero
authors.forename: Maxwell
authors.initials: M
authors.lastname: Wetherington
authors.forename: Eric
authors.initials: E
authors.lastname: Frantz
authors.forename: Michael
authors.initials: M
authors.lastname: Labella
authors.forename: Zachary
authors.initials: Z
authors.lastname: Hughes
authors.forename: Mark
authors.initials: M
authors.lastname: Fanton
authors.forename: David
authors.initials: D
authors.lastname: Snyder