(Invited) Ultrafast Carrier Dynamics in Silicon Nanocrystal Films
Bibliographic record
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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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".