Transient dielectric functions of Ge, Si, and InP from femtosecond pump-probe ellipsometry
Journal article, 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.

Author

Shirly Espinoza

J. Heyrovsky Institute of Physical Chemistry of the CAS

Steffen Richter

Leipzig University

J. Heyrovsky Institute of Physical Chemistry of the CAS

Mateusz Rebarz

J. Heyrovsky Institute of Physical Chemistry of the CAS

Oliver Herrfurth

Leipzig University

Ruediger Schmidt-Grund

Leipzig University

Jakob Andreasson

Chalmers, Physics, Materials Physics

Stefan Zollner

New Mexico State University

J. Heyrovsky Institute of Physical Chemistry of the CAS

Applied Physics Letters

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

Vol. 115 5 052105

Subject Categories

Atom and Molecular Physics and Optics

Other Physics Topics

Condensed Matter Physics

DOI

10.1063/1.5109927

More information

Latest update

10/5/2022