Solution-Processed Ceria Interface Layer for Enhancing Performance of Avalanche Amorphous-Selenium Photodetectors
Bibliographic record
Abstract
Photodiodes using amorphous-selenium (a-Se) have gained significant attention in medical imaging due to their avalanche phenomena. At electric fields above 70 V/μm, holes in a-Se undergo impact ionization which increases the effective sensitivity of the photodetector. However, at the high electric fields required for avalanche gain, dark current due to charge injection from metallic electrode can become a significant source of noise, limiting the dynamic range of the device. A non-insulating n-type hole blocking layer (HBL) is required to minimize the dark current noise from charge injection while conducting only electrons. Among previously reported HBLs, vacuum deposited bulk cerium dioxide (CeO2) have been successfully utilized in n-i-p avalanche a-Se sensors. However, bulk CeO2 cannot be directly deposited on a-Se and suffers from high dark current due to lower effective hole barrier for CeO2 (2.8 eV). In our work, we successfully synthesized colloidal CeO2 quantum dots (QDs) with a large bandgap (Eg = 3.77 eV), which are electronically passivated by surfactants/ligands and spin coated directly on a-Se at room temperature without inducing crystallization. Our prototype device achieved an ultra-low dark current of 30 pA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 70 V/μm which is three orders of magnitude lower than any avalanche a-Se device previously reported and may be the lowest dark current ever recorded for an avalanche device operated at room temperature signifying the potential importance of utilization of solution-processed QDs as HBL.
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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 | 0.001 |
| Open science | 0.001 | 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".