title: Strain-Engineered Graphene Grown on Hexagonal Boron Nitride by Molecular Beam Epitaxy.
abstract: Graphene grown by high temperature molecular beam epitaxy on hexagonal boron nitride (hBN) forms continuous domains with dimensions of order 20 μm, and exhibits moiré patterns with large periodicities, up to ~30 nm, indicating that the layers are highly strained. Topological defects in the moiré patterns are observed and attributed to the relaxation of graphene islands which nucleate at different sites and subsequently coalesce. In addition, cracks are formed leading to strain relaxation, highly anisotropic strain fields, and abrupt boundaries between regions with different moiré periods. These cracks can also be formed by modification of the layers with a local probe resulting in the contraction and physical displacement of graphene layers. The Raman spectra of regions with a large moiré period reveal split and shifted G and 2D peaks confirming the presence of strain. Our work demonstrates a new approach to the growth of epitaxial graphene and a means of generating and modifying strain in graphene.
authors.affiliation: School of Physics &Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: Alex
authors.initials: A
authors.lastname: Summerfield
authors.affiliation: School of Physics &Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK.|School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: Andrew
authors.initials: A
authors.lastname: Davies
authors.affiliation: School of Physics &Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: Tin S
authors.initials: TS
authors.lastname: Cheng
authors.affiliation: School of Physics &Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Korolkov
authors.affiliation: School of Physics &Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: YongJin
authors.initials: Y
authors.lastname: Cho
authors.affiliation: School of Physics &Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Mellor
authors.affiliation: School of Physics &Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: C Thomas
authors.initials: CT
authors.lastname: Foxon
authors.affiliation: School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: Andrei N
authors.initials: AN
authors.lastname: Khlobystov
authors.affiliation: The National Institute for Materials Science, Advanced Materials Laboratory, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Watanabe
authors.affiliation: The National Institute for Materials Science, Advanced Materials Laboratory, 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Taniguchi
authors.affiliation: School of Physics &Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: Laurence
authors.initials: L
authors.lastname: Eaves
authors.affiliation: School of Physics &Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Novikov
authors.affiliation: School of Physics &Astronomy, University of Nottingham, Nottingham, NG7 2RD, UK.
authors.forename: Peter H
authors.initials: PH
authors.lastname: Beton