Origin of luminescence from<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mi mathvariant="normal">Ga</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi mathvariant="normal">O</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>nanostructures studied using x-ray absorption and luminescence spectroscopy
Bibliographic record
Abstract
The origin of the luminescence from ${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ microcrystallites and nanostructures has been studied using time-resolved x-ray excited optical luminescence and x-ray absorption near-edge structure spectra in total electron yield and photoluminescence yield. The ${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ nanostructures exhibit a crystalline $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ core and an amorphous oxide shell, an ultraviolet (UV) and a red emission with a shorter lifetime and a blue and a yellow emission with a longer lifetime when they are excited by x-ray. We suggest that the UV and red emissions from the ${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ nanostructures are from the amorphous shell, while the blue and yellow emissions are from the crystalline $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ core; that the UV and red emissions are due to the presence of a subband of the amorphous ${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$, in the band gap. Our suggestion is in contrast to the previously proposed model, in which the UV emission from ${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ is attributed to an intrinsic transition of crystalline $\ensuremath{\beta}\text{\ensuremath{-}}{\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$. The implications of these observations are discussed.
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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 | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
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".