Structural consequences of hydrogen intercalation of epitaxial graphene on SiC(0001)

Journal Article · Mon Oct 20 04:00:00 EDT 2014 · Applied Physics Letters

DOI:https://doi.org/10.1063/1.4899142· OSTI ID:22350945

Johns, James E.; McBriarty, Martin E.; Hersam, Mark C. ^[1]; Wheeler, Virginia H.; Kurt Gaskill, D. ^[2]; Detlefs, Blanka ^[3]

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1. Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States)
2. U.S. Naval Research Laboratory, Washington, DC 20375 (United States)
3. ESRF—The European Synchrotron, CS 40220, 71, Avenue des Martyrs, 38043 Grenoble (France)

The intercalation of various atomic species, such as hydrogen, to the interface between epitaxial graphene (EG) and its SiC substrate is known to significantly influence the electronic properties of the graphene overlayers. Here, we use high-resolution X-ray reflectivity to investigate the structural consequences of the hydrogen intercalation process used in the formation of quasi-free-standing (QFS) EG/SiC(0001). We confirm that the interfacial layer is converted to a layer structurally indistinguishable from that of the overlying graphene layers. This newly formed graphene layer becomes decoupled from the SiC substrate and, along with the other graphene layers within the film, is vertically displaced by ∼2.1 Å. The number of total carbon layers is conserved during the process, and we observe no other structural changes such as interlayer intercalation or expansion of the graphene d-spacing. These results clarify the under-determined structure of hydrogen intercalated QFS-EG/SiC(0001) and provide a precise model to inform further fundamental and practical understanding of the system.

• OSTI ID: 22350945
• Journal Information: Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 16 Vol. 105; ISSN APPLAB; ISSN 0003-6951
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CLATHRATES
EPITAXY
EXPANSION
FILMS
GRAPHENE
HYDROGEN
INTERFACES
LAYERS
REFLECTIVITY
RESOLUTION
SILICON CARBIDES
SUBSTRATES
X RADIATION