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Unraveling the Ultrafast Hot Electron Dynamics in Semiconductor Nanowires

Wittenbecher, Lukas LU ; Viñas Boström, Emil LU ; Vogelsang, Jan LU ; Lehman, Sebastian LU ; Dick, Kimberly A. LU ; Verdozzi, Claudio LU ; Zigmantas, Donatas LU and Mikkelsen, Anders LU (2021) In ACS Nano 15(1). p.1133-1144
Abstract

Hot electron relaxation and transport in nanostructures involve a multitude of ultrafast processes whose interplay and relative importance are still not fully understood, but which are relevant for future applications in areas such as photocatalysis and optoelectronics. To unravel these processes, their dynamics in both time and space must be studied with high spatiotemporal resolution in structurally well-defined nanoscale objects. We employ time-resolved photoemission electron microscopy to image the relaxation of photogenerated hot electrons within InAs nanowires on a femtosecond time scale. We observe transport of hot electrons to the nanowire surface within 100 fs caused by surface band bending. We find that electron-hole... (More)

Hot electron relaxation and transport in nanostructures involve a multitude of ultrafast processes whose interplay and relative importance are still not fully understood, but which are relevant for future applications in areas such as photocatalysis and optoelectronics. To unravel these processes, their dynamics in both time and space must be studied with high spatiotemporal resolution in structurally well-defined nanoscale objects. We employ time-resolved photoemission electron microscopy to image the relaxation of photogenerated hot electrons within InAs nanowires on a femtosecond time scale. We observe transport of hot electrons to the nanowire surface within 100 fs caused by surface band bending. We find that electron-hole scattering substantially influences hot electron cooling during the first few picoseconds, while phonon scattering is prominent at longer time scales. The time scale of cooling is found to differ between the well-defined wurtzite and zincblende crystal segments of the nanowires depending on excitation light polarization. The scattering and transport mechanisms identified will play a role in the rational design of nanostructures for hot-electron-based applications.

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author
; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
charge carrier relaxation, charge carrier transport, Fermi level pinning, hot electrons, photoemission electron microscopy, semiconductor nanowires, ultrafast microscopy
in
ACS Nano
volume
15
issue
1
pages
1133 - 1144
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:85099955104
  • pmid:33439621
ISSN
1936-0851
DOI
10.1021/acsnano.0c08101
language
English
LU publication?
yes
id
25f12d28-d37e-4edf-980a-e1e147861969
date added to LUP
2021-02-08 09:25:21
date last changed
2021-06-08 01:17:34
@article{25f12d28-d37e-4edf-980a-e1e147861969,
  abstract     = {<p>Hot electron relaxation and transport in nanostructures involve a multitude of ultrafast processes whose interplay and relative importance are still not fully understood, but which are relevant for future applications in areas such as photocatalysis and optoelectronics. To unravel these processes, their dynamics in both time and space must be studied with high spatiotemporal resolution in structurally well-defined nanoscale objects. We employ time-resolved photoemission electron microscopy to image the relaxation of photogenerated hot electrons within InAs nanowires on a femtosecond time scale. We observe transport of hot electrons to the nanowire surface within 100 fs caused by surface band bending. We find that electron-hole scattering substantially influences hot electron cooling during the first few picoseconds, while phonon scattering is prominent at longer time scales. The time scale of cooling is found to differ between the well-defined wurtzite and zincblende crystal segments of the nanowires depending on excitation light polarization. The scattering and transport mechanisms identified will play a role in the rational design of nanostructures for hot-electron-based applications. </p>},
  author       = {Wittenbecher, Lukas and Viñas Boström, Emil and Vogelsang, Jan and Lehman, Sebastian and Dick, Kimberly A. and Verdozzi, Claudio and Zigmantas, Donatas and Mikkelsen, Anders},
  issn         = {1936-0851},
  language     = {eng},
  number       = {1},
  pages        = {1133--1144},
  publisher    = {The American Chemical Society (ACS)},
  series       = {ACS Nano},
  title        = {Unraveling the Ultrafast Hot Electron Dynamics in Semiconductor Nanowires},
  url          = {http://dx.doi.org/10.1021/acsnano.0c08101},
  doi          = {10.1021/acsnano.0c08101},
  volume       = {15},
  year         = {2021},
}