Origin of Luminescence from Silicon Nanocrystals: a Near Edge X-ray Absorption Fine Structure (NEXAFS) and X-ray Excited Optical Luminescence (XEOL) Study of Oxide-Embedded and Free-Standing Systems
Bibliographic record
Abstract
We report an X-ray-based investigation of the formation and luminescent properties of oxide-embedded silicon nanocrystals (Si-NCs) formed by the thermolysis of hydrogen silsesquioxane (HSQ). Near edge X-ray absorption fine structure (NEXAFS) spectroscopy at the Si K-edge was used to monitor the evolving electronic characteristics of silicon during the thermal disproportionation of HSQ, from noncrystalline elemental silicon clusters at 500 °C to well-defined Si-NCs in a SiO 2 -like matrix at 1100 °C. X-ray excited optical luminescence (XEOL) was employed to examine the luminescent properties of the oxide-embedded Si-NCs and identified two emission bands centered at 780 and 540 nm in the optical spectrum. Energy selective XEOL and X-ray photoelectron spectroscopy (XPS) determined that the 540 nm emission band is a result of a well-defined interfacial species bridging the Si-NCs with the surrounding oxide matrix. Energy selective XEOL spectroscopy of oxide-free, freestanding hydride-terminated Si-NCs conclusively established that the emission from sub-5nm Si-NCs is a result of quantum confinement effects.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".