| DOI | Resolve DOI: https://doi.org/10.1149/1.3700406 |
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| Author | Search for: Titova, Lyubov V.; Search for: Cocker, Tyler L.; Search for: Wang, Xiongyao1; Search for: Meldrum, Al1; Search for: Hegmann, Frank A. |
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| Affiliation | - National Research Council of Canada. Security and Disruptive Technologies
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| Format | Text, Article |
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| Conference | 2nd International Symposium on Nanoscale Luminescent Materials - 221st ECS Meeting, May 6-10, 2012, Seattle, WA, USA |
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| Subject | Carrier localization; Drude models; Filling fractions; Interface defects; Interface scattering; Nanocrystal sizes; Optical emissions; Percolation thresholds; Photoexcited carriers; Picosecond time scale; Si nanocrystal; Silicon nanocrystals; Thz spectroscopy; Time variations; Time-resolved; Time-scales; Ultrafast carrier dynamics; Nanocrystals; Nanotechnology; Optical waveguides; Percolation (computer storage); Percolation (fluids); Photoexcitation; Silicon; Interfaces (materials) |
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| Abstract | We have applied time-resolved THz spectroscopy to probe the transient photoexcited carrier dynamics and THz conductivity in Si nanocrystal films with varying silicon volume filling fractions and nanocrystal sizes on picosecond time scales. The THz conductivity reveals microscopic carrier motion with significant interface scattering within nanocrystals as well as percolative transport between nanocrystals. The time variation of the THz conductivity is analyzed within the framework of the Drude-Smith model, an extension of the Drude model that characterizes carrier localization in nanostructured materials. Below the percolation threshold, transport between nanocrystals is inhibited and photoexcited carriers are localized within individual nanocrystals. These films also exhibit efficient optical emission. In films with Si filling fractions above the percolation threshold, photoluminescence is suppressed and a transition from long-range inter-nanocrystal transport immediately after photoexcitation to increased carrier localization over a 50 ps time scale due to accumulation of charges at interface defect sites is observed. |
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| Publication date | 2012 |
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| Language | English |
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| Peer reviewed | Yes |
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| NPARC number | 21270221 |
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| Export citation | Export as RIS |
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| Report a correction | Report a correction (opens in a new tab) |
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| Record identifier | 1af14a35-2335-46d8-b840-ba89897c326b |
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| Record created | 2014-01-13 |
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| Record modified | 2020-04-21 |
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