Transient terahertz conductivity in photoexcited silicon nanocrystal films
- 19 May 2006
- journal article
- research article
- Published by American Physical Society (APS) in Physical Review B
- Vol. 73 (19), 193311
- https://doi.org/10.1103/physrevb.73.193311
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 interface states.
Keywords
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