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Optical and Thermal Behavior of Germanium Thin Films under Femtosecond Laser Irradiation

In this study, we theoretically investigate the response of a germanium thin film under femtosecond pulsed laser irradiation. Electron and lattice temperatures, as well as material-specific optical properties such as dielectric function and reflectivity, were calculated during the irradiation using...

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Autores principales: Abdelmalek, Ahmed, Kotsedi, Lebogang, Bedrane, Zeyneb, Amara, El-Hachemi, Girolami, Marco, Maaza, Malik
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9657278/
https://www.ncbi.nlm.nih.gov/pubmed/36364560
http://dx.doi.org/10.3390/nano12213786
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author Abdelmalek, Ahmed
Kotsedi, Lebogang
Bedrane, Zeyneb
Amara, El-Hachemi
Girolami, Marco
Maaza, Malik
author_facet Abdelmalek, Ahmed
Kotsedi, Lebogang
Bedrane, Zeyneb
Amara, El-Hachemi
Girolami, Marco
Maaza, Malik
author_sort Abdelmalek, Ahmed
collection PubMed
description In this study, we theoretically investigate the response of a germanium thin film under femtosecond pulsed laser irradiation. Electron and lattice temperatures, as well as material-specific optical properties such as dielectric function and reflectivity, were calculated during the irradiation using an extended two-temperature model coupled with the carrier density rate equation and the Drude model. Melting and ablation fluence thresholds were also predicted, resulting in 0.14 J cm(−2) and 0.35 J cm(−2), respectively. An ultrafast change in both optical and thermal properties was detected upon laser irradiation. Results also indicate that thermal melting occurs after germanium takes on a metallic character during irradiation, and that the impact ionization process may have a critical role in the laser-induced thermal effect. Therefore, we suggest that the origin of the thermal modification of germanium surface under femtosecond laser irradiation is mostly due the impact ionization process and that its effect becomes more important when increasing the laser fluence.
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spelling pubmed-96572782022-11-15 Optical and Thermal Behavior of Germanium Thin Films under Femtosecond Laser Irradiation Abdelmalek, Ahmed Kotsedi, Lebogang Bedrane, Zeyneb Amara, El-Hachemi Girolami, Marco Maaza, Malik Nanomaterials (Basel) Article In this study, we theoretically investigate the response of a germanium thin film under femtosecond pulsed laser irradiation. Electron and lattice temperatures, as well as material-specific optical properties such as dielectric function and reflectivity, were calculated during the irradiation using an extended two-temperature model coupled with the carrier density rate equation and the Drude model. Melting and ablation fluence thresholds were also predicted, resulting in 0.14 J cm(−2) and 0.35 J cm(−2), respectively. An ultrafast change in both optical and thermal properties was detected upon laser irradiation. Results also indicate that thermal melting occurs after germanium takes on a metallic character during irradiation, and that the impact ionization process may have a critical role in the laser-induced thermal effect. Therefore, we suggest that the origin of the thermal modification of germanium surface under femtosecond laser irradiation is mostly due the impact ionization process and that its effect becomes more important when increasing the laser fluence. MDPI 2022-10-27 /pmc/articles/PMC9657278/ /pubmed/36364560 http://dx.doi.org/10.3390/nano12213786 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Abdelmalek, Ahmed
Kotsedi, Lebogang
Bedrane, Zeyneb
Amara, El-Hachemi
Girolami, Marco
Maaza, Malik
Optical and Thermal Behavior of Germanium Thin Films under Femtosecond Laser Irradiation
title Optical and Thermal Behavior of Germanium Thin Films under Femtosecond Laser Irradiation
title_full Optical and Thermal Behavior of Germanium Thin Films under Femtosecond Laser Irradiation
title_fullStr Optical and Thermal Behavior of Germanium Thin Films under Femtosecond Laser Irradiation
title_full_unstemmed Optical and Thermal Behavior of Germanium Thin Films under Femtosecond Laser Irradiation
title_short Optical and Thermal Behavior of Germanium Thin Films under Femtosecond Laser Irradiation
title_sort optical and thermal behavior of germanium thin films under femtosecond laser irradiation
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9657278/
https://www.ncbi.nlm.nih.gov/pubmed/36364560
http://dx.doi.org/10.3390/nano12213786
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