Transient terahertz conductivity in photoexcited silicon nanocrystal films

David Cooke, A. N. MacDonald, A. Hryciw, J. Wang, Q. Li, A Meldrum, F. A. Hegmann

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

Time-resolved terahertz spectroscopy is used to probe ultrafast carrier dynamics and terahertz conductivity in photoexcited thin films of silicon nanocrystals, polynanocrystalline silicon, and epitaxial silicon-on-sapphire. We show that a Drude-Smith model provides an excellent fit to the observed transient terahertz conductivity in all of our samples, revealing a transition from a Drude-like response with low carrier backscatter in bulk silicon-on-sapphire to a non-Drude-like, localized behavior with high carrier backscatter in the silicon nanocrystal films. Evidence for long-range conduction between nanocrystals is observed, and we show that the photoconductive lifetime of the silicon nanocrystals is dominated by trapping at Si/SiO2 interface states.
Original languageEnglish
JournalPhysical Review B Condensed Matter
Volume73
Issue number19
Pages (from-to)193311
ISSN0163-1829
DOIs
Publication statusPublished - 2006
Externally publishedYes

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