Correlation of Electrical Response and Structural Phase Transitions in Bi2O3 Nanowires Articles uri icon

authors

publication date

  • October 2018

start page

  • 1

end page

  • 8

issue

  • 19

volume

  • 215

International Standard Serial Number (ISSN)

  • 1862-6300

Electronic International Standard Serial Number (EISSN)

  • 1862-6319

abstract

  • The electric response of Bi2O3 nanowires is studied by means of impedance spectroscopy at high temperatures and compared to a reference bulk Bi2O3 ceramic. Nanowires present the alfa to delta phase transition at a similar temperature than the ceramic (1007 vs. 1010 K), showing an increase of over two orders of magnitude in the conductance. On cooling, nanowires change directly to the alfa phase instead of presenting metastable phases, like the bulk sample. Both samples present a dominant ionic contribution in the delta phase which is also present in the alfa phase at the highest temperatures. X‐ray absorption spectroscopy (XAS) measurements reveal no differences in the short range structural order of both kinds of samples at room temperature, while a detailed analysis by high temperature X‐ray diffraction (HTXRD) confirms the transitions observed in the conductance measurements. The authors relate the direct phase transition delta → alfa in nanowires to a lower thermal conductivity in these nanostructures.

keywords

  • ionic transport; nanostructured materials; oxide semiconductors; x-ray absorption; x-ray diffraction