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Optical Materials Express

Optical Materials Express

  • Editor: David J. Hagan
  • Vol. 4, Iss. 2 — Feb. 1, 2014
  • pp: 300–307

Ultrafast carrier dynamics and optical properties of nanoporous silicon at terahertz frequencies

J. R. Knab, Xinchao Lu, Felipe A. Vallejo, Gagan Kumar, Thomas E. Murphy, and L. Michael Hayden  »View Author Affiliations

Optical Materials Express, Vol. 4, Issue 2, pp. 300-307 (2014)

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We have investigated the broadband terahertz (THz) optical properties of nanoporous silicon samples with different porosities and the ultrafast carrier dynamics of photogenerated charge carriers in these materials. Following photoexcitation, we observe a fast carrier recovery time consisting of two dominant recombination processes with decay constants below ~10 ps. All samples exhibit initially low THz absorption that increases at higher frequencies, and is likely due to contributions from phonon bands and oxidation of the porous surface. The refractive index depends on porosity but shows little frequency dependence. These properties indicate that nanoporous silicon is a useful material for fast, ultrabroadband THz applications (e.g. intensity modulation).

© 2014 Optical Society of America

OCIS Codes
(320.7130) Ultrafast optics : Ultrafast processes in condensed matter, including semiconductors
(160.4236) Materials : Nanomaterials
(300.6495) Spectroscopy : Spectroscopy, teraherz

ToC Category:

Original Manuscript: November 19, 2013
Revised Manuscript: December 28, 2013
Manuscript Accepted: December 28, 2013
Published: January 13, 2014

J. R. Knab, Xinchao Lu, Felipe A. Vallejo, Gagan Kumar, Thomas E. Murphy, and L. Michael Hayden, "Ultrafast carrier dynamics and optical properties of nanoporous silicon at terahertz frequencies," Opt. Mater. Express 4, 300-307 (2014)

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