Growth structure and work function of bilayer graphene on Pd(111)

Using in situ low-energy electron microscopy and density functional theory, we studied the growth structure and work function of bilayer graphene on Pd(111). Low-energy electron diffraction analysis established that the two graphene layers have multiple rotational orientations relative to each other...

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Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2012-05, Vol.85 (20), Article 205443
Main Authors: Murata, Y, Nie, S, Ebnonnasir, A, Starodub, E, Kappes, B B, McCarty, K F, Ciobanu, C V, Kodambaka, S
Format: Article
Language:English
Subjects:
Condensed matter
Electrostatics
Graphene
Low energy
Nucleation
Orientation
Palladium
Planes
Work functions
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Summary:Using in situ low-energy electron microscopy and density functional theory, we studied the growth structure and work function of bilayer graphene on Pd(111). Low-energy electron diffraction analysis established that the two graphene layers have multiple rotational orientations relative to each other and the substrate plane. We observed heterogeneous nucleation and simultaneous growth of multiple, faceted layers prior to the completion of second layer. We propose that the faceted shapes are due to the zigzag-terminated edges bounding graphene layers growing under the larger overlying layers. We also found that the work functions of bilayer graphene domains are higher than those of monolayer graphene, and depend sensitively on the orientations of both layers with respect to the substrate. Based on first-principles simulations, we attribute this behavior to oppositely oriented electrostatic dipoles at the graphene/Pd and graphene/graphene interfaces, the strengths of which depend on the orientations of the two graphene layers.
ISSN:1098-0121
1550-235X
DOI:10.1103/physrevb.85.205443