Fabrication of Black Silicon With Thermostable Infrared Absorption by Femtosecond Laser
Annealing-insensitive black silicon with high absorption below the silicon bandgap has been achieved by femtosecond laser direct writing. Spike microstructures with sizes ranging from 4 to 25 μm are formed on the surface layer of silicon substrate, and a large amount of phospho...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
IEEE
2016-01-01
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| Series: | IEEE Photonics Journal |
| Subjects: | |
| Online Access: | https://ieeexplore.ieee.org/document/7590103/ |
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| Summary: | Annealing-insensitive black silicon with high absorption below the silicon bandgap has been achieved by femtosecond laser direct writing. Spike microstructures with sizes ranging from 4 to 25 μm are formed on the surface layer of silicon substrate, and a large amount of phosphorous impurities (<inline-formula><tex-math notation="LaTeX"> $10^{21}\,{\rm{cm}}^{- 3}$</tex-math></inline-formula>) is doped during the resolidification process. The infrared absorption of phosphorus-doped black silicon decreases slightly with both the annealing temperature and duration. Excitingly, the largest decrease is less than 10% at 2 μm (annealing 240 min at 873K). This thermostable infrared absorption is related to free carrier absorption. After laser irradiation, the phosphorus-doped layer maintains a relatively high crystallinity that can be improved further during thermal annealing. The density of the electrically activated impurities is approximately <inline-formula><tex-math notation="LaTeX"> $10^{19}\,{\rm{cm}}^{- 3}$</tex-math></inline-formula>. |
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| ISSN: | 1943-0655 |