Oxygen incorporation into strontium titanate single crystals from CO2 dissociation

Abstract

Oxygen incorporation from CO(2) into Fe-doped SrTiO(3)(100) single crystals (0.013 at% Fe, 0.039 at% Fe and 0.13 at% Fe) was investigated. Oxygen incorporation processes using (13)C(18)O(2) as the gas source were studied by isotope exchange depth profiling (IEDP) and subsequent secondary-ion mass spectroscopy (SIMS). The interaction of CO(2) with SrTiO(3) (100) surfaces was further studied with different surface analytical techniques like metastable induced electron spectroscopy (MIES), ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS). Results indicate that CO(2) interaction with SrTiO(3) (100) surfaces does not change the surface at all. It seems that CO(2) provides a very low sticking probability on the surface as it is not traced by valence band spectroscopy even at room temperature. Nonetheless, (13)C(18)O(2) acts as an incorporation source of (18)O into the Fe-doped SrTiO(3) single crystals. The diffusion coefficient exhibits a peculiar behaviour when Fe concentration increases. No carbon incorporation is observed at all.