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[en] We study the femtosecond carrier dynamics of n-type doped and biaxially strained Ge-on-Si films which occurs upon impulsive photoexcitation by means of broadband near-IR transient absorption spectroscopy. The modeling of the experimental data takes into account the static donor density in a modified rate equation for the description of the temporal recombination dynamics. The measurements confirm the negligible contribution at a high n-type doping concentration, in the 10(19)cm(-3) range, of Auger processes as compared to defect-related Shockley-Read-Hall recombination. Energy resolved dynamics reveal further insights into the doping-related band structure changes and suggest a reshaping of direct and indirect conduction band valleys to a single effective valley along with a significant spectral broadening of the optical transitions.
[University of Luxembourg > Faculty of Science, Technology and Communication (FSTC) > Physics and Materials Science Research Unit]
