Ultrafast carrier recombination in highly n-doped Ge-on-Si films
| Autor: | Jonas Allerbeck, Giovanni Capellini, Daniele Brida, Yuji Yamamoto, Andreas J. Herbst, Michele Virgilio |
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| Přispěvatelé: | Allerbeck, J., Herbst, A. J., Yamamoto, Y., Capellini, G., Virgilio, M., Brida, D. |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Physics and Astronomy (miscellaneous) Transient-absorption spectroscopy Thin films Electronic bandstructure 02 engineering and technology 01 natural sciences Molecular physics Condensed Matter::Materials Science Photoexcitations 0103 physical sciences Ultrafast laser spectroscopy Femtosecond carrier dynamics Doping Electronic band structure Spectroscopy Charge recombination Electronic bandstructure Photoexcitations Doping Femtosecond carrier dynamics Transient-absorption spectroscopy Thin films 010302 applied physics Rate equation 021001 nanoscience & nanotechnology Charge recombination Photoexcitation Femtosecond 0210 nano-technology Doppler broadening |
| Popis: | 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 1019 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.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 1019 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. |
| Databáze: | OpenAIRE |
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