title: Self-Catalyzed Growth of Vertically Aligned InN Nanorods by Metal-Organic Vapor Phase Epitaxy.
abstract: Vertically aligned hexagonal InN nanorods were grown mask-free by conventional metal-organic vapor phase epitaxy without any foreign catalyst. The In droplets on top of the nanorods indicate a self-catalytic vapor-liquid-solid growth mode. A systematic study on important growth parameters has been carried out for the optimization of nanorod morphology. The nanorod N-polarity, induced by high temperature nitridation of the sapphire substrate, is necessary to achieve vertical growth. Hydrogen, usually inapplicable during InN growth due to formation of metallic indium, and silane are needed to enhance the aspect ratio and to reduce parasitic deposition beside the nanorods on the sapphire surface. The results reveal many similarities between InN and GaN nanorod growth showing that the process despite the large difference in growth temperature is similar. Transmission electron microscopy, spatially resolved energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy have been performed to analyze the structural properties. Spatially resolved cathodoluminescence investigations are carried out to verify the optical activity of the InN nanorods. The InN nanorods are expected to be the material of choice for high-efficiency hot carrier solar cells.
authors.affiliation: Institut für Nanoarchitekturen für die Energieumwandlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner Platz 1, 14109 Berlin, Germany.|Institute of Optics, Information and Photonics, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Staudtstr. 7/B2, 91058 Erlangen, Germany.|Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Tessarek
authors.affiliation: Institut für Mikro- und Nanostrukturforschung & Center for Nanoanalysis and Electron Microscopy (CENEM), Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Cauerstr. 6, 91058 Erlangen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Fladischer
authors.affiliation: Institut für Mikro- und Nanostrukturforschung & Center for Nanoanalysis and Electron Microscopy (CENEM), Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Cauerstr. 6, 91058 Erlangen, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Dieker
authors.affiliation: Institut für Nanoarchitekturen für die Energieumwandlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner Platz 1, 14109 Berlin, Germany.|Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Sarau
authors.affiliation: Institute of Optics, Information and Photonics, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Staudtstr. 7/B2, 91058 Erlangen, Germany.|Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Hoffmann
authors.affiliation: Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Bashouti
authors.affiliation: Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Göbelt
authors.affiliation: Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Heilmann
authors.affiliation: Institute of Optics, Information and Photonics, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Staudtstr. 7/B2, 91058 Erlangen, Germany.|Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Latzel
authors.affiliation: Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Butzen
authors.affiliation: Institute of Solid State Physics, University of Bremen , Otto-Hahn-Allee 1, 28359 Bremen, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Figge
authors.affiliation: Institute of Solid State Physics, University of Bremen , Otto-Hahn-Allee 1, 28359 Bremen, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Gust
authors.affiliation: Institut für Nanoarchitekturen für die Energieumwandlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner Platz 1, 14109 Berlin, Germany.|Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Höflich
authors.affiliation: Institut für Nanoarchitekturen für die Energieumwandlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner Platz 1, 14109 Berlin, Germany.|Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Feichtner
authors.affiliation: Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Büchele
authors.affiliation: Institut für Nanoarchitekturen für die Energieumwandlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner Platz 1, 14109 Berlin, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Schwarzburg
authors.affiliation: Institut für Mikro- und Nanostrukturforschung & Center for Nanoanalysis and Electron Microscopy (CENEM), Friedrich-Alexander-University Erlangen-Nürnberg (FAU) , Cauerstr. 6, 91058 Erlangen, Germany.
authors.forename: E
authors.initials: E
authors.lastname: Spiecker
authors.affiliation: Institut für Nanoarchitekturen für die Energieumwandlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH , Hahn-Meitner Platz 1, 14109 Berlin, Germany.|Max Planck Institute for the Science of Light , Günther-Scharowsky-Str. 1, 91058 Erlangen, Germany.|Physics Department, Freie Universität Berlin , Arnimallee 14, 14195 Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Christiansen
keywords: InN; MOVPE; cathodoluminescence; growth; nanorods; vapor−liquid−solid