TY - JOUR
T1 - Unconventional Shrinkage of Hot Electron Distribution in Metal Directly Visualized by Ultrafast Imaging
AU - Gao, Guoquan
AU - Jiang, Lan
AU - Xue, Bofeng
AU - Yang, Fei
AU - Wang, Ti
AU - Wan, Yan
AU - Zhu, Tong
N1 - Publisher Copyright:
© 2023 Wiley-VCH GmbH.
PY - 2023/2/17
Y1 - 2023/2/17
N2 - 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.
AB - 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.
KW - electron–phonon coupling
KW - high spatiotemporal resolution imaging
KW - hot electron transport
KW - interfacial heat transfer
KW - transient reflection dynamics
UR - http://www.scopus.com/inward/record.url?scp=85146087996&partnerID=8YFLogxK
U2 - 10.1002/smtd.202201260
DO - 10.1002/smtd.202201260
M3 - Article
C2 - 36617685
AN - SCOPUS:85146087996
SN - 2366-9608
VL - 7
JO - Small Methods
JF - Small Methods
IS - 2
M1 - 2201260
ER -