Transient dielectric functions of Ge, Si, and InP from femtosecond pump-probe ellipsometry
Artikel i vetenskaplig tidskrift, 2019

Transient dielectric functions with a 120 fs time resolution of Ge, Si, and InP were acquired from 1.7 to 3.5eV with a femtosecond pump-probe rotating-compensator ellipsometer. The intensity of the pump laser (with 1.55, 3.10, or 4.65eV photon energy) was adjusted to create an initial near-surface carrier density of 10(20)cm(-3). In Ge, there is a significant (similar to 15%) decrease in the E-1 and E-1+Delta(1) 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-1 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 Delta and Gamma do not participate in interband transitions between 1.7 and 3.5eV.


Shirly Espinoza

Ústav fyzikální chemie J. Heyrovského AV ČR

Steffen Richter

Universität Leipzig

Ústav fyzikální chemie J. Heyrovského AV ČR

Mateusz Rebarz

Ústav fyzikální chemie J. Heyrovského AV ČR

Oliver Herrfurth

Universität Leipzig

Ruediger Schmidt-Grund

Universität Leipzig

Jakob Andreasson

Chalmers, Fysik, Materialfysik

Stefan Zollner

Ústav fyzikální chemie J. Heyrovského AV ČR

New Mexico State University

Applied Physics Letters

0003-6951 (ISSN) 1077-3118 (eISSN)

Vol. 115 5 052105


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