Berlin 2024 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 13: Poster I

HL 13.32: Poster

Monday, March 18, 2024, 15:00–18:00, Poster E

The influence of Band bending on valence band offsets determined by Kraut’s method: Modeling and experiment for polar-discontinuity doped LaInO₃/BaSnO₃ — •Georg Hoffmann¹, Aysha A Riaz², Anna Regoutz², Oliver Brandt¹, and Oliver Bierwagen¹ — ¹Paul-Drude-Institut für Festkörperelektronik, Leibniz-Institut im Forschungsverbund Berlin e. V., Hausvogteiplatz 5-7, 10117 Berlin, Germany — ²Department of Chemistry, University College London , London, UK

Two-dimensional electron gases (2DEGs) in LaAlO₃/SrTiO₃ heterostructures due to polar discontinuity have brought huge attention to perovskite oxides [1]. For LaInO₃/BaSnO₃ heterostructures, a predicted conduction band offset (CBO) of 1.6 eV confines a charge carrier density of up to 2×10¹⁴ cm⁻² in the quantum well at the BaSnO₃ side [2], while room temperature mobilities are higher by one order of magnitude compared to SrTiO₃ based 2DEGs. To determine the CBO considering interfacial band bending the related valence band offset (VBO) is determined by Kraut’s method using x-ray photo electron spectroscopy (XPS) [3].

We developed a model that predicts XPS core-level (CL) shape and shift for given band profiles and thus related VBO correction. Synchrotron-based XPS data are interpreted with this model to determine band bending and VBO at the LaInO₃/BaSnO₃ interface.

[1] J. Mannhart, et al., MRS bulletin 33, 1027-1034 (2008). [2] W. Aggoune, and Claudia Draxl, npj Computational Materials 7, 174 (2021). [3] E. A. Kraut, et al., Phys. Rev. Lett. 44, 1620 (1980).

Keywords: Perovskites; Photo electron spectroscopy; two-dimensional electron gas; conduction band offset; band bending