| AVS 66th International Symposium & Exhibition | |
| Spectroscopic Ellipsometry Focus Topic | Wednesday Sessions |
| Session EL+EM-WeA |
| Session: | Spectroscopic Ellipsometry: Novel Applications and Theoretical Approaches |
| Presenter: | Shirly Espinoza, Institute of Physics, Academy of Sciences of the Czech Republic, Czechia |
| Authors: | S.J. Espinoza, Institute of Physics, Academy of Sciences of the Czech Republic, Czechia S. Richter, Institute of Physics, Academy of Sciences of the Czech Republic, Czechia M. Rebarz, Institute of Physics, Academy of Sciences of the Czech Republic, Czechia O. Herrfurth, Universität Leipzig, Felix-Bloch-Institut für Festkörperphysik, Germany R. Schmidt, Universität Leipzig, Felix-Bloch-Institut für Festkörperphysik, Germany J. Andreasson, Institute of Physics, Academy of Sciences of the Czech Republic, Czechia S. Zollner, New Mexico State University |
| Correspondent: | Click to Email |
Recent developments in time-resolved ellipsometry allow us to study the ultrafast behavior of single crystals of undoped Ge, InP and Si at room temperature after carriers have been excited by an ultrashort laser pulse of 1.55 eV. Information about the dynamic processes such as scattering mechanisms of the hot charge carriers and electron-phonon coupling was obtained.
With a resolution of 120 fs, and a time scale from femtoseconds to nanoseconds, the observed changes are bigger in Ge than in the other materials. Our results are in agreement with theoretical and experimental work done some years ago on the dynamics of germanium studied by time-resolved ellipsometry [1,2]. The result of our experiments could go deeper into the details of the dynamics thanks to the development of the time-resolved experimental setup using state of the art technology in the fields of ultrafast lasers, electronics, and optics.
Our current spectral range is from 1.7 to 3.5 eV. The generated carrier density is on the order of 1020 cm−3, which allows us to compare the results with published data on doped materials [3].
References
[1] Choo H.R., Hu X.F., Downer M.C., Kesan V.P. Femtosecond ellipsometric study of nonequilibrium carrier dynamics in Ge and epitaxial Si1−xGex. Appl. Phys. Lett. 63, 1507 (1993)
[2] Zollner S., Myers K.D., Jensen K.G., Dolan J.M., Bailey D.W., Stanton C.J. Femtosecond interband hole scattering in Ge studied by pump-probe reflectivity. Solid State Commun. 104 (1), 51-55 (1997)
[3] Xu C., Fernando N.S., Zollner S., Kouvetaki J., Menendez J. Observation of Phase-Filling Singularities in the Optical Dielectric Function of Highly Doped n-Type Ge. Phys. Rev. Let. 118, 267402 (2017)