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HL: Fachverband Halbleiterphysik
HL 33: Nitrides: Devices
HL 33.3: Vortrag
Mittwoch, 19. März 2025, 11:45–12:00, H15
Stabilizing Ta3N5 Thin Films Photoelectrodes by Defect Engineering — •Lukas M. Wolz1, Gabriel Grötzner1,2, Tim Rieth1,2, Laura I. Wagner1,2, Matthias Kuhl1, Johannes Dittloff1,2, Guanda Zhou1,2, Saswati Santra1,2, Verena Streibel1,2, Frans Munnik3, Ian D. Sharp1,2, and Johanna Eichhorn1 — 1Physics Department, TUM School of Natural Sciences, Technische Universität München, Germany — 2Walter Schottky Institute, Technische Universität München, Germany — 3Helmholtz-Zentrum Dresden-Rossendorf, Dresden, Germany
Tantalum nitride (Ta3N5) is a highly investigated photoelectrode material due to its favorable optoelectronic properties for photoelectrochemical (PEC) energy conversion. However, intrinsic defects such as nitrogen vacancies and oxygen impurities play a crucial role in defining their optical, electronic, and photoelectrochemical properties. While the role of these defects in PEC activity is well investigated, their impact on material stability remains underexplored. We investigate the relationship between atomic-scale defects and macroscale PEC stability in Ta3N5 thin films. To reveal the impact of each defect type on the material properties, we introduced different defect concentrations in Ta3N5 by using three different precursors in the synthesis process. Low oxygen concentrations are found to increase long-range order but lead to high concentrations of deep-level defects, leading to increased charge recombination and decreased material stability. Conversely, higher oxygen contents result in reduced structural order but beneficially passivate deep-level defects, leading to improved stability.
Keywords: Photoinduced water splitting; Stability; Defects; Optical Properties; Deep level traps