Unconventional Shrinkage of Hot Electron Distribution in Metal Directly Visualized by Ultrafast Imaging

Guoquan Gao, Lan Jiang, Bofeng Xue, Fei Yang, Ti Wang, Yan Wan, Tong Zhu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Elucidation of hot carrier transport and cooling mechanisms at the micro-/nanoscale is critical for optoelectronics, thermal management, and photocatalysis. Spatiotemporal evolution of hot electrons is usually convoluted with their ultrafast dynamics. Herein, an ultrafast microscopy is employed to directly track the spatiotemporal distribution of photoexcited hot electrons, providing a transformative approach to unravel the competitive relationship of transport and cooling. In the temporal evolution profiles of hot electron distribution, an anomalous contracting stage showing obvious thickness and fluence dependency is observed, with a characteristic end time indicating the completion of electron–phonon (e-ph) thermalization. Hot electron transport plays a prominent role in the competition with e-ph coupling, while interfacial heat dissipation dominates nonequilibrium state evolution with thickness below ballistic length. This work significantly enriches the tool kit of ultrafast techniques and provides guidance for rational design and optimization of micro-/nanodevices.

Original languageEnglish
Article number2201260
JournalSmall Methods
Volume7
Issue number2
DOIs
Publication statusPublished - 17 Feb 2023

Keywords

  • electron–phonon coupling
  • high spatiotemporal resolution imaging
  • hot electron transport
  • interfacial heat transfer
  • transient reflection dynamics

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Gao, G., Jiang, L., Xue, B., Yang, F., Wang, T., Wan, Y., & Zhu, T. (2023). Unconventional Shrinkage of Hot Electron Distribution in Metal Directly Visualized by Ultrafast Imaging. Small Methods, 7(2), Article 2201260. https://doi.org/10.1002/smtd.202201260