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The dependence of band intensities in the Raman spectrum of individual single-crystal ruthenium dioxide (RuO2) nanowires on the angle between the plane of polarization of the exciting (and collected) light and the long axis of the nanowire, is shown to be a simple, complementary technique to high resolution transmission electron microscopy (HRTEM) for determining nanowire growth direction. We show that excellent agreement exists between what is observed and what is predicted for the polarization angle dependence of the intensities of the nanowires’ Eg (525 cm-1) and the B2g (714 cm-1) Raman bands, only by assuming that the nanowires grow along the (001) crystallographic direction, as confirmed by HRTEM. [ABSTRACT FROM AUTHOR]

We report a facile method for synthesizing single-crystal rutile TiO2 nanowires using atmospheric-pressure, chemical vapor deposition with Ti and TiO as precursors. The synthesis is found to depend critically on the predeposition of a layer of metallic Ti on the Ni catalysts layer. The omission of this step seems previously to have impeded the efficient synthesis of titania nanowires. Single-nanowire field-effect transistors showed the TiO2 nanowires to be n-type semiconductors with conductance activation energy of ∼58 meV. [ABSTRACT FROM AUTHOR]

This letter discusses Mg incorporation in GaN nanowires with diameters ∼35 nm, fabricated by vapor–liquid–solid synthesis in p-type nanowires. Turning on the Mg doping halfway through the synthesis produced nanowires with p–n junctions that showed excellent rectification properties down to 2.6 K. The nanowires are shown to possess good-quality, crystalline, hexagonal GaN inner cores surrounded by an amorphous GaN outer layer. Most wires grow such that the crystalline c axis is normal to the long axis of the nanowire. The temperature dependence of the current–voltage characteristics is consistent with electron tunneling through a voltage-dependent barrier. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]