article published Jonathan Diederich author Jennifer Velazquez Rojas author Agnieszka Paszuk author Mohammad Amin Zare Pour author Christian Höhn author Isaac Azahel Ruiz Alvarado author Klaus Schwarzburg author David Ostheimer author Rainer Eichberger author Wolf Gero Schmidt author 4680000-0002-2717-5076 Thomas Hannappel author Roel van de Krol author Dennis Friedrich author 15 department 170 department 295 department 35 department 230 department <jats:title>Abstract</jats:title><jats:p>The current efficiency records for generating green hydrogen via solar water splitting are held by indium phosphide (InP)‐based photo‐absorbers, protected by TiO<jats:sub>2</jats:sub> layers grown through atomic layer deposition (ALD). InP is also a leading material for photonic integrated circuits and computing, where ultrafast near‐surface behavior is key. A previous study described electronic pathways at the phosphorus‐rich (P‐rich) surface of p‐doped InP(100) using time‐resolved two‐photon photoemission (tr‐2PPE) spectroscopy. Here, the intricate electron pathways of the P‐rich InP surface modified with ALD‐deposited TiO<jats:sub>2</jats:sub> are explored. Photoexcited bulk InP electrons migrate through a bulk‐to‐surface transition cluster of states and surface states and inject into the TiO<jats:sub>2</jats:sub> conduction band (CB). Energy levels and occupation dynamics of CB states in P‐rich InP and TiO<jats:sub>2</jats:sub> adlayers are observed, with discrete states preserved up to 10 nm TiO<jats:sub>2</jats:sub> deposition. Thermalization lifetimes of excited electrons &gt; 0.8 eV above the InP conduction band minimum (CBM) are preserved for layer thicknesses up to 2.5 nm. Annealing at 300 °C to achieve crystalline TiO<jats:sub>2</jats:sub> reconstructions destroys interfacial states, affecting charge transfer. These observations enable innovative engineering of the P‐rich InP/TiO<jats:sub>2</jats:sub> heterointerface, opening new possibilities for studying hot‐carrier extraction, adsorbate effects, surface plasmons, and improving photovoltaic and PEC water‐splitting devices.</jats:p> Wiley2024 eng 1616-301X 1616-302810.1002/adfm.202409455 3449 @article{Diederich_Rojas_Paszuk_Pour_Höhn_Alvarado_Schwarzburg_Ostheimer_Eichberger_Schmidt_et al._2024, title={Ultrafast Electron Dynamics at the P‐rich Indium Phosphide/TiO₂ Interface}, volume={34}, DOI={<a href="https://doi.org/10.1002/adfm.202409455">10.1002/adfm.202409455</a>}, number={492409455}, journal={Advanced Functional Materials}, publisher={Wiley}, author={Diederich, Jonathan and Rojas, Jennifer Velazquez and Paszuk, Agnieszka and Pour, Mohammad Amin Zare and Höhn, Christian and Alvarado, Isaac Azahel Ruiz and Schwarzburg, Klaus and Ostheimer, David and Eichberger, Rainer and Schmidt, Wolf Gero and et al.}, year={2024} } J. Diederich, J.V. Rojas, A. Paszuk, M.A.Z. Pour, C. Höhn, I.A.R. Alvarado, K. Schwarzburg, D. Ostheimer, R. Eichberger, W.G. Schmidt, T. Hannappel, R. van de Krol, D. Friedrich, Advanced Functional Materials 34 (2024). Diederich J, Rojas JV, Paszuk A, et al. Ultrafast Electron Dynamics at the P‐rich Indium Phosphide/TiO₂ Interface. <i>Advanced Functional Materials</i>. 2024;34(49). doi:<a href="https://doi.org/10.1002/adfm.202409455">10.1002/adfm.202409455</a> Diederich, Jonathan, Jennifer Velazquez Rojas, Agnieszka Paszuk, Mohammad Amin Zare Pour, Christian Höhn, Isaac Azahel Ruiz Alvarado, Klaus Schwarzburg, et al. “Ultrafast Electron Dynamics at the P‐rich Indium Phosphide/TiO₂ Interface.” <i>Advanced Functional Materials</i> 34, no. 49 (2024). <a href="https://doi.org/10.1002/adfm.202409455">https://doi.org/10.1002/adfm.202409455</a>. J. Diederich <i>et al.</i>, “Ultrafast Electron Dynamics at the P‐rich Indium Phosphide/TiO₂ Interface,” <i>Advanced Functional Materials</i>, vol. 34, no. 49, Art. no. 2409455, 2024, doi: <a href="https://doi.org/10.1002/adfm.202409455">10.1002/adfm.202409455</a>. Diederich, Jonathan, et al. “Ultrafast Electron Dynamics at the P‐rich Indium Phosphide/TiO₂ Interface.” <i>Advanced Functional Materials</i>, vol. 34, no. 49, 2409455, Wiley, 2024, doi:<a href="https://doi.org/10.1002/adfm.202409455">10.1002/adfm.202409455</a>. Diederich, J., Rojas, J. V., Paszuk, A., Pour, M. A. Z., Höhn, C., Alvarado, I. A. R., Schwarzburg, K., Ostheimer, D., Eichberger, R., Schmidt, W. G., Hannappel, T., van de Krol, R., &#38; Friedrich, D. (2024). Ultrafast Electron Dynamics at the P‐rich Indium Phosphide/TiO₂ Interface. <i>Advanced Functional Materials</i>, <i>34</i>(49), Article 2409455. <a href="https://doi.org/10.1002/adfm.202409455">https://doi.org/10.1002/adfm.202409455</a> 613592025-09-18T11:37:51Z2025-12-05T13:35:09Z