Femtosecond dephasing in porous silicon
We determine dephasing times T2 in free standing porous silicon samples using nondegenerate four-wave mixing. Within the framework of an idealized inhomogeneously broadened two-level system, values of 20 fs for different porosities are obtained. Fast energy relaxation times are found in the range of...
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| Veröffentlicht in: | Applied physics letters 1996-06, Vol.68 (23), p.3296-3298 |
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| Hauptverfasser: | , , , , |
| Format: | Artikel |
| Sprache: | eng |
| Online-Zugang: | Volltext |
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| Zusammenfassung: | We determine dephasing times T2 in free standing porous silicon samples using nondegenerate four-wave mixing. Within the framework of an idealized inhomogeneously broadened two-level system, values of 20 fs for different porosities are obtained. Fast energy relaxation times are found in the range of 1.5–3.5 ps for 64%–73% porosities, respectively. They are attributed to carrier thermalization within the band tails, originating from porous silicon nanocrystallites and their surface states. |
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| ISSN: | 0003-6951 1077-3118 |
| DOI: | 10.1063/1.116579 |