title: Free-standing millimetre-long Bi2Te3 sub-micron belts catalyzed by TiO2 nanoparticles.
abstract: Physical vapour deposition (PVD) is used to grow millimetre-long Bi2Te3 sub-micron belts catalysed by TiO2 nanoparticles. The catalytic efficiency of TiO2 nanoparticles for the nanostructure growth is compared with the catalyst-free growth employing scanning electron microscopy. The catalyst-coated and catalyst-free substrates are arranged side-by-side, and overgrown at the same time, to assure identical growth conditions in the PVD furnace. It is found that the catalyst enhances the yield of the belts. Very long belts were achieved with a growth rate of 28 nm/min. A ∼1-mm-long belt with a rectangular cross section was obtained after 8 h of growth. The thickness and width were determined by atomic force microscopy, and their ratio is ∼1:10. The chemical composition was determined to be stoichiometric Bi2Te3 using energy-dispersive X-ray spectroscopy. Temperature-dependent conductivity measurements show a characteristic increase of the conductivity at low temperatures. The room temperature conductivity of 0.20 × 10(5) S m (-1) indicates an excellent sample quality.
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK.
authors.forename: Piet
authors.initials: P
authors.lastname: Schönherr
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK.|University of Science and Technology of China, Jinzhai Rd. 96, Hefei, 230026, China.
authors.forename: Fengyu
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Humboldt-Universität zu Berlin, Newtonstr. 15, Berlin, 12489, Germany.
authors.forename: Danny
authors.initials: D
authors.lastname: Kojda
authors.affiliation: Humboldt-Universität zu Berlin, Newtonstr. 15, Berlin, 12489, Germany.
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Mitdank
authors.affiliation: Leibniz-Institut für Kristallzüchtung - IKZ, Berlin, 12489, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Albrecht
authors.affiliation: Humboldt-Universität zu Berlin, Newtonstr. 15, Berlin, 12489, Germany.
authors.forename: Saskia F
authors.initials: SF
authors.lastname: Fischer
authors.affiliation: Clarendon Laboratory, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK. thorsten.hesjedal@physics.ox.ac.uk.
authors.forename: Thorsten
authors.identifier: http://orcid.org/0000-0001-7947-3692
authors.initials: T
authors.lastname: Hesjedal
keywords: Bismuth telluride; Nanowires; Temperature-dependent conductivity; Topological insulators