Regensburg 2025 – scientific programme

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O: Fachverband Oberflächenphysik

O 23: Poster Ultrafast Electron Dynamics

O 23.15: Poster

Monday, March 17, 2025, 18:00–20:00, P2

Towards ultrafast momentum microscopy of exciton dynamics at ZnO surfaces — •Hashima Marukara, Junde Liu, and Stefan Mathias — Georg-August-Universität Göttingen, I. Physikalisches Institut, Germany

The semiconductor ZnO, known for its wide band gap and high exciton binding energy, stands out as a promising material among transparent conductive oxides for applications in optoelectronics and catalysis[1,2]. Surface excitons, i.e. bound electron-hole pairs localized at the material's surface, play a crucial role in mediating its optical and electronic properties, significantly influencing energy conversion processes at the surfaces [3]. An ideal tool to study these ultrafast processes is time- and angle-resolved photoelectron spectroscopy, which gives access to the exciton landscape and the relevant excitation and relaxation pathways. In our new project within the CRC1633 ``Proton-coupled electron transfer", we aim to study the ultrafast surface exciton dynamics at the ZnO(10-10) surface using our Göttingen time-resolved momentum microscopy setup. By using this technique, which gives us access to full energy and momentum space, we aim to gain detailed information on the ZnO's exciton momentum and real-space properties (localized/delocalized/defect/etc.) and the accompanying exciton dynamics [4].

[1] Gierster et al., Nat Commun 12, 978 (2021)

[2] Foglia et al., Struct. Dyn. 6, 034501 (2019)

[3] Deinert et al., Phys. Rev. Lett. 113 057602 (2014)

[4] Reutzel et al., Advances in Physics X 9, 2378722 (2024)

Keywords: Ultrafast momentum microscopy; trARPES; exciton dynamics