title: Tunable Ultra-high Aspect Ratio Nanorod Architectures grown on Porous Substrate via Electromigration.
abstract: The interplay between porosity and electromigration can be used to manipulate atoms resulting in mass fabrication of nanoscale structures. Electromigration usually results in the accumulation of atoms accompanied by protrusions at the anode and atomic depletion causing voids at the cathode. Here we show that in porous media the pattern of atomic deposition and depletion is altered such that atomic accumulation occurs over the whole surface and not just at the anode. The effect is explained by the interaction between atomic drift due to electric current and local temperature gradients resulting from intense Joule heating at constrictions between grains. Utilizing this effect, a porous silver substrate is used to mass produce free-standing silver nanorods with very high aspect ratios of more than 200 using current densities of the order of 10(8) A/m(2). This simple method results in reproducible formation of shaped nanorods, with independent control over their density and length. Consequently, complex patterns of high quality single crystal nanorods can be formed in-situ with significant advantages over competing methods of nanorod formation for plasmonics, energy storage and sensing applications.
authors.affiliation: Department of Physics, King's College London, Strand, London WC2R 2LS, UK.
authors.forename: Ali
authors.initials: A
authors.lastname: Mansourian
authors.affiliation: Department of Physics, King's College London, Strand, London WC2R 2LS, UK.
authors.forename: Seyed Amir
authors.initials: SA
authors.lastname: Paknejad
authors.affiliation: Department of Physics and Materials Science and Centre for Functional Photonics (CFP), City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong.
authors.forename: Qiannan
authors.initials: Q
authors.lastname: Wen
authors.affiliation: Centre for Ultrastructural Imaging (CUI), King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, UK.
authors.forename: Gema
authors.initials: G
authors.lastname: Vizcay-Barrena
authors.affiliation: Centre for Ultrastructural Imaging (CUI), King's College London, New Hunt's House, Guy's Campus, London, SE1 1UL, UK.
authors.forename: Roland A
authors.initials: RA
authors.lastname: Fleck
authors.affiliation: Department of Physics, King's College London, Strand, London WC2R 2LS, UK.
authors.forename: Anatoly V
authors.initials: AV
authors.lastname: Zayats
authors.affiliation: Department of Physics, King's College London, Strand, London WC2R 2LS, UK.
authors.forename: Samjid H
authors.initials: SH
authors.lastname: Mannan