Photoluminescence in tensile-strained Si type-II quantum wells on bulk single-crystal SiGe substrates
Bibliographic record
Abstract
Near-band edge photoluminescence (PL) in high-quality tensile-strained Si type-II quantum wells (QWs) with varying well width grown on bulk crystal SiGe substrates by using ultrahigh vacuum chemical vapor deposition has been studied. In contrast to the blueshifts observed in the PL lines of Si1−xGex QWs on Si, the PL lines of Si QWs exhibit redshifts with increasing excitation density. The PL from the SiGe substrate shows no such shift. The excitation-induced PL redshifts decrease as the well width decreases, and are essentially independent of temperature up to 15 K. The rapid thermal annealing (RTA) was found to improve the crystal quality of the samples. RTA enhances the integrated PL intensity, results in narrowing and blueshifting of PL bands at a given excitation density, and reduces the exponent in the excitation power dependence as well as the amount of excitation-induced PL redshifting. Possible mechanisms for the observed excitation-induced PL redshifts were examined, including band bending, band filling, and binding of excitons to impurities.
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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) | 0.000 | 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) | 0.000 | 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".