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HL: Fachverband Halbleiterphysik
HL 5: Heterostructures, interfaces and surfaces
HL 5.4: Talk
Monday, March 27, 2023, 10:45–11:00, POT 112
Band alignment of thin strontium germanate layer on silicon from ab initio — •Tomáš Rauch1,2, Pavel Marton3,4, Silvana Botti1,2, and Jiří Hlinka3 — 1Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität Jena, Germany — 2European Theoretical Spectroscopy Facility — 3Institute of Physics of the Czech Academy of Sciences, Praha, Czech Republic — 4Institute of Mechatronics and Computer Engineering, Technical University of Liberec, Czech Republic
Silicon is one of the most used materials for optoelectronic applications. In photo-catalytic cells for hydrogen evolution reaction, Si must be capped by a protective layer, additionally allowing the photo-excited electrons to travel to the device surface. It has been demonstrated, that SrTiO3 (STO) can fulfill these two functions [1].
In this work, we studied SrGeO3 (SGO) as an alternative to STO, using density-functional theory. We calculated the structural properties of a chosen prototypical SGO/Si(001) interface and studied its electronic structure, focusing on the band offsets between Si and SGO. We found a metallic type-III interface with occupied conduction bands of SGO and a charge transfer from Si to SGO. Aligning the local band edges of the thin SGO layer with the redox potentials allows us to conclude that the SGO/Si interface should be suitable for water reduction.
We acknowledge funding by the Czech Science Foundation (project no. 21-20110K) and by the Volkswagen Foundation (project “dandelion”).
[1] Li Ji et al., Nat. Nanotechnol. 10, 84 (2015)