Transient dielectric functions of Ge, Si, and InP from femtosecond pump-probe ellipsometry
(2019) In Applied Physics Letters 115(5).- Abstract
Transient dielectric functions with a 120 fs time resolution of Ge, Si, and InP were acquired from 1.7 to 3.5 eV with a femtosecond pump-probe rotating-compensator ellipsometer. The intensity of the pump laser (with 1.55, 3.10, or 4.65 eV photon energy) was adjusted to create an initial near-surface carrier density of 1020 cm-3. In Ge, there is a significant (∼15%) decrease in the E1 and E1 + Δ1 critical point absorption and a Kramers-Kronig consistent change in the refractive index because photoexcited electrons at L block these transitions and reduce their amplitudes. Only a small redshift of the E1 critical point is observed, which we attribute to lattice heating and... (More)
Transient dielectric functions with a 120 fs time resolution of Ge, Si, and InP were acquired from 1.7 to 3.5 eV with a femtosecond pump-probe rotating-compensator ellipsometer. The intensity of the pump laser (with 1.55, 3.10, or 4.65 eV photon energy) was adjusted to create an initial near-surface carrier density of 1020 cm-3. In Ge, there is a significant (∼15%) decrease in the E1 and E1 + Δ1 critical point absorption and a Kramers-Kronig consistent change in the refractive index because photoexcited electrons at L block these transitions and reduce their amplitudes. Only a small redshift of the E1 critical point is observed, which we attribute to lattice heating and exchange-correlation effects. Minimal changes were found for Si and InP, where electrons near Δand Γ do not participate in interband transitions between 1.7 and 3.5 eV.
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- author
- Espinoza, Shirly ; Richter, Steffen LU ; Rebarz, Mateusz ; Herrfurth, Oliver ; Schmidt-Grund, Rüdiger ; Andreasson, Jakob and Zollner, Stefan
- publishing date
- 2019-07-29
- type
- Contribution to journal
- publication status
- published
- in
- Applied Physics Letters
- volume
- 115
- issue
- 5
- article number
- 052105
- publisher
- American Institute of Physics (AIP)
- external identifiers
-
- scopus:85073886140
- ISSN
- 0003-6951
- DOI
- 10.1063/1.5109927
- language
- English
- LU publication?
- no
- additional info
- Publisher Copyright: © 2019 Author(s).
- id
- 5278aea8-021f-411a-80ce-ffcaeaddd6cf
- date added to LUP
- 2022-04-19 14:48:22
- date last changed
- 2022-04-29 11:23:11
@article{5278aea8-021f-411a-80ce-ffcaeaddd6cf,
abstract = {{<p>Transient dielectric functions with a 120 fs time resolution of Ge, Si, and InP were acquired from 1.7 to 3.5 eV with a femtosecond pump-probe rotating-compensator ellipsometer. The intensity of the pump laser (with 1.55, 3.10, or 4.65 eV photon energy) was adjusted to create an initial near-surface carrier density of 10<sup>20</sup> cm<sup>-3</sup>. In Ge, there is a significant (∼15%) decrease in the E<sub>1</sub> and E<sub>1</sub> + Δ<sub>1</sub> critical point absorption and a Kramers-Kronig consistent change in the refractive index because photoexcited electrons at L block these transitions and reduce their amplitudes. Only a small redshift of the E<sub>1</sub> critical point is observed, which we attribute to lattice heating and exchange-correlation effects. Minimal changes were found for Si and InP, where electrons near Δand Γ do not participate in interband transitions between 1.7 and 3.5 eV.</p>}},
author = {{Espinoza, Shirly and Richter, Steffen and Rebarz, Mateusz and Herrfurth, Oliver and Schmidt-Grund, Rüdiger and Andreasson, Jakob and Zollner, Stefan}},
issn = {{0003-6951}},
language = {{eng}},
month = {{07}},
number = {{5}},
publisher = {{American Institute of Physics (AIP)}},
series = {{Applied Physics Letters}},
title = {{Transient dielectric functions of Ge, Si, and InP from femtosecond pump-probe ellipsometry}},
url = {{http://dx.doi.org/10.1063/1.5109927}},
doi = {{10.1063/1.5109927}},
volume = {{115}},
year = {{2019}},
}