Charge Trapping at Chemically Modified Si(111) Surfaces Studied by Optical Second Harmonic Generation
Bibliographic record
Abstract
Covalent chemical modification of Si(111) surfaces by attachment of organic monolayers with terminal tert -butylhydrazide groups is described. Second harmonic generation studies of the hydrazide-modified surfaces in air show the presence of an electric field induced second harmonic (EFISH) response, indicative of charge trapping at the surface. Charge trapping is associated with the hydrazide group and is not observed for other organic monolayers or oxidized silicon surfaces. Charging is reversible and can be modulated by variation of the gaseous ambient of the sample, including particularly oxygen and water vapor. An interpretation is given in terms of ionosorption of O 2 as an electron trap, with strong stabilization of the electron affinity level of O 2 in the monolayer by polar hydrazide groups and adsorbed water molecules. There is also an indication that the hydrazide group may become ionized, as an electron donor. From the dependence of EFISH on laser irradiance and the observation of a transient EFISH response, it is suggested that ionosorption of O 2 may occur spontaneously in the dark and, in addition, is transiently enhanced by laser photoexcitation of silicon. By comparison with EFISH and high-resolution electron energy loss measurements on oxidized silicon surfaces, the density of charge trapped at hydrazide-modified surfaces has been estimated.
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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) | 0.001 | 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 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".