Changes in local surface structure and Sr depletion in Fe-implanted SrTiO3 (001)

•Fe ion implantation of SrTiO3 and post-implantation results in formation of Sr1-yTi1-xFex+yO3-δ phase.•In Sr1-yTi1-xFex+yO3-δ phase, Fe assumes Fe3+ oxidation state in the bulk and Fe2+ oxidation state in the near surface area.•FEFF9 calculations indicate that Fe ions can substitute both Ti and Sr sites.•Formation of Sr1-yTi1-xFex+yO3-δ phase is accompanied by Sr depletion in the near surface region. Local surface structure of single crystal strontium titanate SrTiO3 (001) samples implanted with Fe in the range of concentrations between 2×1014 to 2×1016Fe/cm2 at 30keV has been investigated. In order to facilitate Fe substitution (doping), implanted samples were annealed in oxygen at 350°C. Sr depletion was observed from the near-surface layers impacted by the ion-implantation process, as revealed by Rutherford Backscattering Spectrometry (RBS), X-ray photoelectron spectroscopy (XPS), X-ray Absorption Near Edge Spectroscopy (XANES), and Atomic Force Microscopy (AFM). Hydrocarbon contaminations on the surface may contribute to the mechanisms of Sr depletion, which have important implications for Sr(Ti1-xFex)O3-δ materials in gas sensing applications.