title: Vertically Oriented Growth of GaN Nanorods on Si Using Graphene as an Atomically Thin Buffer Layer.
abstract: The monolithic integration of wurtzite GaN on Si via metal-organic vapor phase epitaxy is strongly hampered by lattice and thermal mismatch as well as meltback etching. This study presents single-layer graphene as an atomically thin buffer layer for c-axis-oriented growth of vertically aligned GaN nanorods mediated by nanometer-sized AlGaN nucleation islands. Nanostructures of similar morphology are demonstrated on graphene-covered Si(111) as well as Si(100). High crystal and optical quality of the nanorods are evidenced through scanning transmission electron microscopy, micro-Raman, and cathodoluminescence measurements supported by finite-difference time-domain simulations. Current-voltage characteristics revealed high vertical conduction of the as-grown GaN nanorods through the Si substrates. These findings are substantial to advance the integration of GaN-based devices on any substrates of choice that sustains the GaN growth temperatures, thereby permitting novel designs of GaN-based heterojunction device concepts.
authors.affiliation: Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, D-91058 Erlangen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Heilmann
authors.affiliation: CrayoNano AS , Otto Nielsens vei 12, NO-7052 Trondheim, Norway.
authors.forename: A Mazid
authors.initials: AM
authors.lastname: Munshi
authors.affiliation: Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, D-91058 Erlangen, Germany.|Institut für Nanoarchitekturen für die Energieumwandlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner Platz 1, D-14109 Berlin, Germany.
authors.forename: George
authors.initials: G
authors.lastname: Sarau
authors.affiliation: Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, D-91058 Erlangen, Germany.
authors.forename: Manuela
authors.initials: M
authors.lastname: Göbelt
authors.affiliation: Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, D-91058 Erlangen, Germany.|Institut für Nanoarchitekturen für die Energieumwandlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner Platz 1, D-14109 Berlin, Germany.|Institute of Optics, Information and Photonics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) , Staudtstr. 7/B2, D-91058 Erlangen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Tessarek
authors.affiliation: Department of Physics, Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim, Norway.
authors.forename: Vidar T
authors.initials: VT
authors.lastname: Fauske
authors.affiliation: Department of Physics, Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim, Norway.
authors.forename: Antonius T J
authors.initials: AT
authors.lastname: van Helvoort
authors.affiliation: School of Photovoltaic and Renewable Energy Engineering, University of New South Wales , Kensington, Sydney, New South Wales 2052, Australia.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Yang
authors.affiliation: Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, D-91058 Erlangen, Germany.|Institute of Optics, Information and Photonics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) , Staudtstr. 7/B2, D-91058 Erlangen, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Latzel
authors.affiliation: Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, D-91058 Erlangen, Germany.|Institute of Optics, Information and Photonics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) , Staudtstr. 7/B2, D-91058 Erlangen, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Hoffmann
authors.affiliation: School of Photovoltaic and Renewable Energy Engineering, University of New South Wales , Kensington, Sydney, New South Wales 2052, Australia.
authors.forename: Gavin
authors.initials: G
authors.lastname: Conibeer
authors.affiliation: CrayoNano AS , Otto Nielsens vei 12, NO-7052 Trondheim, Norway.|Department of Electronics and Telecommunications, Norwegian University of Science and Technology (NTNU) , NO-7491 Trondheim, Norway.
authors.forename: Helge
authors.initials: H
authors.lastname: Weman
authors.affiliation: Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, D-91058 Erlangen, Germany.|Institut für Nanoarchitekturen für die Energieumwandlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner Platz 1, D-14109 Berlin, Germany.|Physics Department, Freie Universität Berlin , Arnimallee 14, D-14195 Berlin, Germany.
authors.forename: Silke
authors.initials: S
authors.lastname: Christiansen
keywords: GaN; GaN-on-Si; MOVPE; graphene; nanorods