Dresden 2014 – scientific programme

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DS: Fachverband Dünne Schichten

DS 6: Thin Film Characterization: Structure Analysis and Composition (XRD, TEM, XPS, SIMS, RBS,...)

DS 6.12: Talk

Monday, March 31, 2014, 18:00–18:15, CHE 89

Strontium segregation in LaAlO3/SrTiO3 and NdGaO3/SrTiO3 oxide heterostructures investigated by XPS — •Uwe Treske¹, Nadine Heming¹, Martin Knupfer¹, Bernd Büchner¹, Emiliano Di Gennaro², Umberto Scotti di Uccio², Fabio Miletto Granozio², and Andreas Koitzsch¹ — ¹Institute for Solid State Research, IFW-Dresden, P.O. Box 270116, DE-01171 Dresden, Germany — ²CNR-SPIN and Dipartimento di Fisica, Complesso Universitario di Monte S.Angelo, Via Cintia, 80126 Naples, Italy

Pulsed laser deposition grown LaAlO₃ and NdGaO₃ on TiO₂-terminated SrTiO₃ with different film thicknesses were investigated by soft X-ray photoemission spectroscopy. The surface sensitivity of the measurements has been tuned by varying photon energy hν and emission angle Θ. In contrast to the core levels of the other elements, the Sr 3d line shows an unexpected splitting for higher surface sensitivity, signaling the presence of a second unexpected strontium component. From our quantitative analysis we conclude that during the growth process Sr atoms diffuse away from the substrate and segregate at the surface of the heterostructure, possibly forming strontium oxide.