title: Polarity-Induced Selective Area Epitaxy of GaN Nanowires.
abstract: We present a conceptually novel approach to achieve selective area epitaxy of GaN nanowires. The approach is based on the fact that these nanostructures do not form in plasma-assisted molecular beam epitaxy on structurally and chemically uniform cation-polar substrates. By in situ depositing and nitridating Si on a Ga-polar GaN film, we locally reverse the polarity to induce the selective area epitaxy of N-polar GaN nanowires. We show that the nanowire number density can be controlled over several orders of magnitude by varying the amount of predeposited Si. Using this growth approach, we demonstrate the synthesis of single-crystalline and uncoalesced nanowires with diameters as small as 20 nm. The achievement of nanowire number densities low enough to prevent the shadowing of the nanowire sidewalls from the impinging fluxes paves the way for the realization of homogeneous core-shell heterostructures without the need of using ex situ prepatterned substrates.
authors.affiliation: Laboratório de Filmes Semicondutores, Universidade Estadual Paulista Bauru , 17033-360 São Paulo, Brazil.
authors.forename: Ziani
authors.initials: Z
authors.lastname: de Souza Schiaber
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Calabrese
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Xiang
authors.initials: X
authors.lastname: Kong
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Achim
authors.initials: A
authors.lastname: Trampert
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Jenichen
authors.affiliation: Laboratório de Filmes Semicondutores, Universidade Estadual Paulista Bauru , 17033-360 São Paulo, Brazil.
authors.forename: José Humberto
authors.initials: JH
authors.lastname: Dias da Silva
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Geelhaar
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Oliver
authors.initials: O
authors.lastname: Brandt
authors.affiliation: Paul-Drude-Institut für Festkörperelektronik , Hausvogteiplatz 5-7, 10117 Berlin, Germany.
authors.forename: Sergio
authors.identifier: 0000-0002-1246-6073
authors.initials: S
authors.lastname: Fernández-Garrido
keywords: Selective area growth; maskless selective area epitaxy; nanocolumn; polarity inversion; semiconductor