title: Gold nanoparticles grown inside carbon nanotubes: synthesis and electrical transport measurements.
abstract: The hybrid structures composed of gold nanoparticles and carbon nanotubes were prepared using porous alumina membranes as templates. Carbon nanotubes were synthesized inside the pores of these templates by the non-catalytic decomposition of acetylene. The inner cavity of the supported tubes was used as nanoreactors to grow gold particles by impregnation with a gold salt, followed by a calcination-reduction process. The samples were characterized by transmission electron microscopy and X-ray energy dispersion spectroscopy techniques. The resulting hybrid products are mainly encapsulated gold nanoparticles with different shapes and dimensions depending on the concentration of the gold precursor and the impregnation procedure. In order to understand the electronic transport mechanisms in these nanostructures, their conductance was measured as a function of temperature. The samples exhibit a 'non-metallic' temperature dependence where the dominant electron transport mechanism is 1D hopping. Depending on the impregnation procedure, the inclusion of gold nanoparticles inside the CNTs can introduce significant changes in the structure of the tubes and the mechanisms for electronic transport. The electrical resistance of these hybrid structures was monitored under different gas atmospheres at ambient pressure. Using this hybrid nanostructures, small amounts of acetylene and hydrogen were detected with an increased sensibility compared with pristine carbon nanotubes. Although the sensitivity of these hybrid nanostructures is rather low compared to alternative sensing elements, their response is remarkably fast under changing gas atmospheres.
authors.affiliation: Instituto de Química y Bioquímica, Facultad de Ciencias, Universidad de Valparaíso, Av. Gran Bretaña 1111, Valparaíso 2340000, Chile.
authors.forename: Rodrigo A
authors.initials: RA
authors.lastname: Segura
authors.affiliation: Instituto de Química y Bioquímica, Facultad de Ciencias, Universidad de Valparaíso, Av. Gran Bretaña 1111, Valparaíso 2340000, Chile.
authors.forename: Claudia
authors.initials: C
authors.lastname: Contreras
authors.affiliation: Departamento de Física, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, Chile.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Henriquez
authors.affiliation: Departamento de Física, Universidad Técnica Federico Santa María, Avenida España 1680, Valparaíso 2390123, Chile.
authors.forename: Patricio
authors.initials: P
authors.lastname: Häberle
authors.affiliation: Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia 166, Santo André, Sao Paulo 09210-170, Brazil.
authors.forename: José Javier S
authors.initials: JJ
authors.lastname: Acuña
authors.affiliation: Instituto de Física, Facultad de Física, Pontificia Universidad Católica de Chile, Vicuña Mackena 4860, Santiago 6904411, Chile.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Adrian
authors.affiliation: Instituto de Física, Facultad de Física, Pontificia Universidad Católica de Chile, Vicuña Mackena 4860, Santiago 6904411, Chile.
authors.forename: Pedro
authors.initials: P
authors.lastname: Alvarez
authors.affiliation: Instituto de Física, Facultad de Física, Pontificia Universidad Católica de Chile, Vicuña Mackena 4860, Santiago 6904411, Chile.
authors.forename: Samuel A
authors.initials: SA
authors.lastname: Hevia
keywords: 81.07.-b; 81.07.De; 81.15.Gh; Au-CNT hybrid; Carbon nanotubes; Electric transport; Gas sensing