SKM 2023 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 26: Interface Controlled Properties and Nanomaterials: Grain Boundaries and Stability, Spectroscopy and Interatomic Potentials

MM 26.10: Talk

Wednesday, March 29, 2023, 12:45–13:00, SCH A 216

Influence of a p-n Heterojunction on the Diffusive Transport in Tungsten Trioxide Thin Films — •Jan L. Dornseifer^{1, 2}, Markus S. Friedrich^{1, 2}, and Peter J. Klar^{1, 2} — ¹Institute of Experimental Physics I, Justus-Liebig-University, Giessen, Germany — ²Center for Materials Research (ZfM), Justus-Liebig-University, Giessen, Germany

Tungsten trioxide (WO₃) is (typically) an n-type semiconductor and a prominent electrochromic material. It changes its optical properties when charge carriers are inserted. Due to its excellent electrochromic properties, WO₃ is the most commonly used functional material in so called "smart" windows which are a promising technology for significantly lowering the energy consumption for building climatization. Industrially manufactured polycrystalline WO₃ thin films were coated with p-type nickel monoxide (NiO_x) thin films by ion beam sputter deposition. In order to investigate the diffusive transport of hydrogen in WO₃ thin films influenced by a p-n heterojunction, spatially and temporally resolved optical transmission measurements are conducted on NiO_x/WO₃-heterostructures during the potentiostatic coloration of the WO₃ thin films. Spatial and temporal diffusion profiles determined by analyzing these measurements indicate that the lateral propagation of hydrogen in NiO_x coated WO₃ films is accelerated. In addition, an increased transmittance is observed in the colored state. To describe these findings, a model is set up based on an increase in hydrogen concentration inside the WO₃ layer outside the space-charge region formed at the NiO_x/WO₃ interface.