Improving the co and ch4 gas sensor response at room temperature of alpha-fe2o3(0001) epitaxial thin films grown on srtio3(111) incorporating au(111) islands Articles uri icon

authors

  • Serrano, Aida
  • Lopez Sanchez, Jesus
  • Arnay, Iciar
  • Cid, Rosalia
  • Vila, Maria
  • SALAS COLERA, EDUARDO
  • Castro, German R.
  • Rubio Zuazo, Juan

publication date

  • July 2021

start page

  • 1

end page

  • 12

issue

  • 7

volume

  • 11

International Standard Serial Number (ISSN)

  • 2079-6412

abstract

  • In this work, the functional character of complex -Fe2O3(0001)/SrTiO3(111) and Au(111)
    islands/ -Fe2O3(0001)/SrTiO3(111) heterostructures has been proven as gas sensors at room temperature.
    Epitaxial Au islands and -Fe2O3 thin film are grown by pulsed laser deposition on SrTiO3(111)
    substrates. Intrinsic parameters such as the composition, particle size and epitaxial character are
    investigated for their influence on the gas sensing response. Both Au and -Fe2O3 layer show an
    island-type growth with an average particle size of 40 and 62 nm, respectively. The epitaxial and
    incommensurate growth is evidenced, confirming a rotation of 30 between the in-plane crystallographic
    axes of -Fe2O3(0001) structure and those of SrTiO3(111) substrate and between the in-plane
    crystallographic axes of Au(111) and those of -Fe2O3(0001) structure. -Fe2O3 is the only phase
    of iron oxide identified before and after its functionalization with Au nanoparticles. In addition, its
    structural characteristics are also preserved after Au deposition, with minor changes at short-range
    order. Conductance measurements of Au(111)/ -Fe2O3(0001)/SrTiO3(111) system show that the
    incorporation of epitaxial Au islands on top of the -Fe2O3(0001) layer induces an enhancement of
    the gas-sensing activity of around 25% under CO and 35% under CH4 gas exposure, in comparison
    to a bare -Fe2O3(0001) layer grown on SrTiO3(111) substrates. In addition, the response of the
    heterostructures to CO gas exposure is around 5–10% higher than to CH4 gas in each case.

keywords

  • au/ -fe2o3 heterostructure; island-type growth; epitaxial growth; surface functionalization; gas sensor activity