Measuring Photoexcited Electron and Hole Dynamics in ZnTe and Modeling Excited State Core-Valence Effects in Transient Extreme Ultraviolet Reflection Spectroscopy

Hanzhe Liu, Jonathan Michelsen, Jocelyn Mendes, Isabel Klein, Sage Bauers, Jake Evans, Andriy Zakutayev, Scott Cushing

Research output: Contribution to journalArticlepeer-review

3 Scopus Citations

Abstract

Transient extreme ultraviolet (XUV) spectroscopy is becoming a valuable tool for characterizing solar energy materials because it can separate photoexcited electron and hole dynamics with element specificity. Here, we use surface-sensitive femtosecond XUV reflection spectroscopy to separately measure photoexcited electron, hole, and band gap dynamics of ZnTe, a promising photocathode for CO2 reduction. We develop an ab initio theoretical framework based on density functional theory and the Bethe-Salpeter equation to robustly assign the complex transient XUV spectra to the material’s electronic states. Applying this framework, we identify the relaxation pathways and quantify their time scales in photoexcited ZnTe, including subpicosecond hot electron and hole thermalization, surface carrier diffusion, ultrafast band gap renormalization, and evidence of acoustic phonon oscillations.

Original languageAmerican English
Pages (from-to)2106-2111
Number of pages6
JournalJournal of Physical Chemistry Letters
Volume14
Issue number8
DOIs
StatePublished - 2023

Bibliographical note

Publisher Copyright:
© 2023 American Chemical Society.

NREL Publication Number

  • NREL/JA-5K00-85614

Keywords

  • electronic states
  • photoexcitation
  • solar energy materials
  • transient extreme ultraviolet spectroscopy

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