Heterjunctions of small molecular weight organic semiconductors
Bibliographic record
Abstract
Photodiodes made of small molecular weight organic semiconductors have been fabricated. The organic materials under investigation are p-type Copper phthalocyanine (CuPc) and n-type 3,4,9,10-perylenetetracarboxylic bisbenzimidazole (PTCBI). Current-voltage and capacitance-voltage measurements have been performed to evaluate the electrical properties of the organic photodiodes. Optical measurements including responsivity and temporal response have also been carried out. It has been found that device efficiency of the photodiodes is influenced by the thickness of organic layers as well as the device structures. It is believed that organic layer thickness is a strong function of materials' exciton diffusion lengths. The thickness of the organic layer employed in the fabricated photodiode is 100 A or less. However, the fabricated devices with thin organic layer showed poor performance in terms of saturation current and breakdown voltage. As a result, new device structures have been proposed to overcome the problems. Stacking structure double heterojunction (SDH) and novel comb-like structure single heterojunction (CSH) device configurations have shown a substantial improvement in both electrical and optical parameters. There is at least 3 times enhancement in photocurrent and 10 times increase in external quantum efficiency for photodiodes employing CSH device structure and 100 A organic layer. Improvements in saturation current and breakdown voltage have also been observed. In addition, responsivity measurements in CSH devices have yielded a 7 times improvement. Furthermore, the carrier lifetime of the photodiode is estimated to be around 1 microsecond from the temporal response measurements. The combined effect of thin organic layers and new device structures leads to an overall improvement in device performance.
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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 | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.010 | 0.002 |
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".