Extracting optical absorption characteristics from semiconductor nanowire arrays
Bibliographic record
Abstract
A method based on extraction of the effective absorption coefficient using Beer-Lambert's law on simulated transmissions is used to understand the optical absorption characteristics of semiconductor nanowire arrays. Three different semiconductor nanowire arrays, viz. silicon (Si), gallium arsenide (GaAs) and amorphous silicon (a-Si), are evaluated using the method. These semiconductors were chosen since two of them have similar real parts of the refractive index in the visible range, while the other two have comparable imaginary parts of the refractive index in the visible range. We examine the roles of the real and imaginary parts of the refractive index in enhancing the absorption characteristics in the nanowire arrays due to the excitation of radial and photonic Bloch modes. We observe that high absorption peaks at modal resonances correspond to the resonance peaks in reflections from the nanowire-air interface. Further, the wavelengths of these two peak resonances are slightly detuned according to the Kramers-Kronig relation for an oscillator system. The study confirms that the resonance wavelengths of radial HE modes are diameter and refractive index dependent. The study extends the understanding to the absorption characteristics due to the excitation of the photonic Bloch modes caused by near-field coupling. Excitation of Bloch modes leads to increased absorption and quality factor as compared to only radial mode excitation. We also conclude that the imaginary part of the refractive index of the semiconductor, influence the diameters at which Bloch modes are excited for a given lattice spacing. We observe that semiconductors with a higher bulk value of absorption coefficient need to be ordered more densely in the nanowire array to be able to excite the photonic crystal modes within the array. Interestingly, we see that for Si, GaAs and a-Si arrays with an equal diameter of 80 nm and lattice spacing of 400 nm, the peak absorption is almost the same, even though GaAs and a-Si are highly absorptive materials compared to Si. Thus, both radial and Bloch mode excitations can be used to design absorption profiles in a semiconductor nanowire array.
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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 | 0.001 |
| 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".