Dresden 2020 – scientific programme

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DS: Fachverband Dünne Schichten

DS 27: Focus Session: Functional Metal Oxides for Novel Applications and Devices I (joint session HL/DS)

DS 27.4: Talk

Wednesday, March 18, 2020, 16:00–16:15, POT 81

Epitaxial growth of La doped BaSnO₃ thin films by Plasma-assisted molecular beam epitaxy — •Georg Hoffmann¹, Martina Zupancic², Martin Albrecht², Zbigniew Galazka², and Oliver Bierwagen¹ — ¹Paul-Drude-Institut für Festkörperelektronik Leibniz-Institut im Forschungsverbund Berlin e.V. — ²Leibniz-Institut für Kristallzüchtung

For oxide molecular beam epitaxy (MBE), the use of suboxides is an essential part for the growth of complex oxides, e.g. SnO for BaSnO₃ (BSO). However, the conventional approach of BSO growth using SnO suboxide from a SnO₂ charge (SnO + Ba + 2O → BaSnO₃) requires high cell temperatures and adds a parasitic oxygen background due to the reaction SnO₂ → SnO + 1/2 O₂. Using a SnO₂ + Sn mixture as a charge can address both issues, first: the suppression of the parasitic oxygen due to the reaction SnO₂ + Sn → 2 SnO and second: providing higher fluxes at lower temperatures.

Using this new approach, smooth BSO films were grown by plasma-assisted MBE on SrTiO₃ (STO) substrates. The crystal quality was analyzed in-situ by reflective high energy electron diffraction. Ex-situ, morphology and structural parameters were determined by atomic force microscopy, X-ray diffraction, and high resolution transmission electron microscopy images.

The results reveal an increased BSO growth-temperature window with decreasing SnO/Ba flux ratio. Further, the influence of the STO miscut angle, as well as the STO orientation will be discussed, and electrical properties of La doped BSO films are pointed out.