Fluence- and temperature-dependent studies of carrier dynamics in radiation-damaged silicon-on-sapphire and amorphous silicon
Bibliographic record
Abstract
We study the effects of lattice damage level, pump fluence, and temperature on carrier dynamics in thin silicon films. Two samples of radiation-damaged silicon-on-sapphire (RD-SOS) and one amorphous silicon thin film on sapphire were investigated. The first RD-SOS sample was O+ implanted with doses of 1×1013 cm−2 at 100 and 200 keV; the second RD-SOS sample was O+ implanted with a dose of 1×1015 cm−2 at 100 and a second dose of 2×1015 cm−2 at 200 keV; the third sample was a nonhydrogenated amorphous-silicon thin film grown by electron-beam evaporation. Carrier concentrations up to 7.4×1020 cm−3 were injected into the samples with 100 fs, 400 nm pump pulses, while the transient optical properties were probed with subpicosecond-wide terahertz (THz) pulses. Using a thin film Drude model, we derived the carrier relaxation time and effective carrier mobility for the three samples. The increase of lattice damage decreased both the relaxation time constant and the carrier mobility. A slight increase in relaxation time was observed for increasing pump fluence, but mobility values were not affected. No change in relaxation time or mobility was found for temperatures from 5 to 300 K. We find average relaxation time constants of 5.5 ps in the first sample, 1.4 ps in the second sample, and 0.58 ps in the third sample, and average carrier mobility values of 383, 44, and 4.4 cm2/V s, respectively. The presence of a single relaxation time constant is consistent with a trap-influenced relaxation mechanism and not of Auger recombination for carrier concentrations <1021 cm−3, indicative of the absence of thermally activated processes in the relaxation mechanism.
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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".