Relation between sodium addition and excess selenium in Bridgman-grown CuInSe 2
Bibliographic record
Abstract
Ingots containing cm-sized monocrystals of CuInSe<sub>2</sub> have been grown in quartz ampoules by a vertical-Bridgman method. Included also in the ampoules were varying quantities of elemental Na, as well as excess Se above stoichiometry. Deposits were seen within the ampoules after growth, including a white deposit formed through a reaction of the Na with the quartz, and a reddish-brown deposit mostly containing Na and Se. Thermoelectric power measurements indicate that stoichiometric material grown with no excess Se and no Na is p-type. With the addition of Na above a critical amount to the ampoule, the resulting ingots were always n-type. This p to n conductivity type change is inhibited when excess Se is also present, and more Na is required for the change to occur. The critical amount of Na was found to be approximately twice the atomic amount of excess Se. XRD indicated that the chalcopyrite structure of the material was maintained with additions of up to 3 at. % Na, even as the material was changed from p- to n-type, and no sodium was detected in the bulk. It is suggested that a reaction between the Na and the Se occurs, resulting in the formation of Na<sub>2</sub>Se. The Se used in this reaction is therefore unable to be a part of the CuInSe<sub>2</sub> lattice, thereby increasing the number of donor-like Se vacancies, rendering it n-type. In this model, the addition of excess Se replaces those Se atoms which react with the Na, so that the material remains p-type.
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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 | 0.001 | 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 | 0.001 |
| 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".