High-photovoltage GaAs vertical epitaxial monolithic heterostructures with 20 thin p/n junctions and a conversion efficiency of 60%
Bibliographic record
Abstract
Photovoltaic power converting III–V semiconductor devices based on the Vertical Epitaxial HeteroStructure Architecture (VEHSA) design have been achieved with up to 20 thin p/n junctions (PT20). Open circuit photovoltages in excess of 23 V are measured for a continuous wave monochromatic optical input power of ∼1 W tuned in the 750 nm–875 nm wavelength range. Conversion efficiencies greater than 60% are demonstrated when the PT20 devices are measured near the peak of their spectral response. Noticeably, the PT20 structure is implemented with its narrowest ultrathin base having a thickness of only 24 nm. In the present study, the spectral response of the PT20 peaks at external quantum efficiency (EQE) of 89%/20 for an input wavelength of 841 nm. We also performed a detailed analysis of the EQE dependence with temperature and for VEHSA structures realised with a varied number of p/n junctions. The systematic study reveals the correlations between the measured conversion efficiencies, the EQE behavior, and the small deviations in the implementation of the optimal designs. Furthermore, we modeled the photovoltage performance of devices designed with thinner bases. For example, we derive that the narrowest subcell of a PT60 structure would have a base as thin as 8 nm, it is expected to still generate an individual subcell photovoltage of 1.14 V, and it will begin to feature 2-dimensional quantum well effects.
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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 | 0.000 | 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 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".