Correlation of dynamical, vibrational and optical properties in c-Si with bond-centered-hydrogen and other hydrogen complexes
Bibliographic record
Abstract
Hydrogen, introduced into crystalline (c-) or amorphous (a-) silicon (Si), plays an important role in improving Si properties for photovoltaics application. Low temperature proton implantation in c-Si and a-Si or H-doping of Si films introduces metastable hydrogen in the bond-centered-position (BCH), which dissociates with increasing temperatures into new metastable complexes. Using ab-initio molecular dynamics we report on the stability of BCH in crystalline Si and its temperature-induced dissociation products at close to solar cell operating temperatures, mainly the newly experimentally discovered H2** dimer, and the H2* dimer, as well as isolated interstitial hydrogen and monohydrides. Each complex leaves a characteristic signature in the frequency spectrum and in the imaginary part of the dielectric constant that agrees well with experiments. All complexes modify the vicinity of the energy gap of clean c-Si. BCH introduces characteristic donor levels just below the conduction band that are occupied, hence raising the Fermi energy considerably, and causing a strong peak in the imaginary part of the dielectric constant in the infrared. The H2** and H2* dimers introduce a low energy tail in the imaginary part of the dielectric constant. The results are important for experimental in-situ optical characterization of Si film growth.
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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".