Berlin 2024 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 36: Poster III
HL 36.53: Poster
Wednesday, March 20, 2024, 18:00–20:30, Poster E
Exploring spin-dependent transport in BiVO4 — •Sven Doll, Melina Pees, David Vogl A., Noah Braitsch, Ian D. Sharp, and Martin S. Brandt — Walter Schottky Institut and School of Natural Sciences, Technische Universität München, 85748 Garching, Germany
Bismuth vanadate BiVO4 is a promising photoanode material for solar-to-fuel conversion. This semiconductor is particularly interesting considering its strong visible light absorption, efficient charge carrier separation, and favorable quasi-Fermi-level alignment with relevant redox potentials. However, small polaron transport strongly reduces its performance. To gain further insight into the charge carrier transport by these polaronic states, we explore whether we can observe a spin dependence of the hopping of the small polarons in BiVO4 using electrically detected magnetic resonance (EDMR). We investigate polycrystalline thin films grown by metal-organic decomposition on conductive and non-conductive transparent substrates. Furthermore, we prepared different electrical contact configurations via physical vapor deposition to analyze in-plane and out-of-plane transport in this material and to achieve small resistances and RC time constants to meet the experimental requirements of EDMR. Since spin-dependent signals are known to critically depend on the charge carrier density (e.g., from similar experiments on doped crystalline silicon), we evaluate the possibility of using the persistent photoconductivity of BiVO4, as well as the introduction of donors in the form of oxygen vacancies and hydrogen impurities, to tune the polaron density.
Keywords: Photoelectrochemistry; BVO; EDMR