Design of Gallium Nitride-Based Photodetector for Enhanced Accuracy in Solar Ultraviolet Index Monitoring
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe manuscript photonics-3154912 by Hanlin Li and co worker’s, proposes a miniature GaN-based erythema response detector that utilizes a double diode integrated chip to closely match the spectral response of the erythema spectrum curve. The detector can precisely correspond the output current to the ultraviolet index, with a measurement error less than 0.4. The experimental results show the detector's measurement accuracy on the ultraviolet index is at an advanced level compared to current commercial ultraviolet detectors. In general, the manuscript is well written however few aspects needs to be address before the publication.
1. How does the spectral response of the proposed GaN-based detector compare to the CIE erythemal action spectrum and other commercially available UV detectors?
2. What is the calculation process for deriving the UVI value from the detector's output current?
3. How was the experimental setup designed to evaluate the measurement accuracy of the GaN-based detector under different ultraviolet spectral irradiance conditions?
4. What are the key findings from the comparison of the theoretical and actual UVI values measured by the GaN-based detector and other commercial detectors?
5. What are the specific advantages of the proposed GaN-based detector in terms of reducing manufacturing costs and requirements for crystal quality compared to traditional erythema response detectors
Comments on the Quality of English LanguageThe overall English writing standard of this document is fairly good. Nonetheless, it is still possible to make some minor adjustments to the grammar or the choice of words which may further enhance the readability.
Author Response
Please see the attachment.
Author Response File: 
Author Response.docx
Reviewer 2 Report
Comments and Suggestions for AuthorsWhile the paper on the miniature GaN-based photodetector addresses the important issue of monitoring solar ultraviolet index (UVI) and mentions several challenges associated with current technologies, it unfortunately does not present any new or significant scientific content. Overall, the paper does not meet the standards of originality or scientific advancement required for publication and should therefore be rejected.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsThe manuscript is very well written and organized. Results are discussed with strong theoretical support. I didn't find any issue that should be answered. I only have a comment and a question.
In the abstract section check grammar for the sentence:
Eight groups of ultraviolet radiation spectra are used to calculate the measurement error of 15 the ultraviolet detector is less than 0.4.
My only question is: did all studied detectors have the same collecting area?
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsIn this work, the authors present a significant advancement in the development of GaN-based PIN ultraviolet (UV) detector through employing the dual-diode integrated chip configuration. The simulation and measurement results provide a detailed analysis on the detecting performance of UV index. We believe this approach can supply a new horizon in the development of highly precise UV detectors. The work is of potential interest for publishing after necessary revisions. Here are some suggestions that the authors could pick up on:
1. In Keywords, the “Miniaturization” is unprecise key word for this work. In this work, the authors did not discuss on the effect of device size on the UV detection performance. Therefore, the “Miniaturization” is suggested to be replaced by “Integration”. Please consider it.
2. In introduction, the authors write: “The wavelength of ultraviolet (UV) radiation falls between visible light and X-rays, and it can be divided into four bands: UVA (320-400 nm), UVB (280-320 nm), UVC (200-280 nm), and VUV (10-200 nm). When sunlight reaches the earth, UV radiation in the 200-280 nm range is absorbed by the ozone layer in the atmosphere and does not reach the surface of the earth [1-4]…people are paying more and more attention to the third-generation semiconductor [13]…GaN-based materials consist of compounds formed by Group III elements aluminum, gallium, indium, and the Group V element nitrogen (GaN, AlN, InN), as well as their multi-component alloys (InGaN, AlGaN, etc.)…This property presents vast opportunities for the development of emerging electronic and optoelectronic devices, such as ultraviolet detectors.” The general reference list in the introduction seems a bit thin, considering the evolution in the field within the recent years. Besides ultraviolet detectors, GaN-based materials has been widely used to create optoelectronic devices, such as light-emitting diodes. To give the readers a much broader view, recent developments concerning on GaN-based LEDs, such as Laser & Photonics Reviews 2024, 18, 2300464, Optics Letters 47(5), 1291-1294 (2022); Laser & Photonics Reviews 2023, 17, 2200455; Nanoscale 14, 4887-4907 (2022), etc. should be added, so that the readers can be clear about the state-of-the-art of this topic.
3. In Fig. 1 and Fig. 3, is the unit of spectral irradiance correct? Should It be corrected as “mW·m-3”? The similar issues occur in Fig. 10(a-h). Please confirm them.
4. In Fig. 4, what is the unit of the “Optical thickness of clouds”? Please specify it.
5. In Table 3, are the simulation parameters, such as “electron SRH lifetime”, “hole SRH lifetime”, “electron effective mass”, “hole effective mass”, “electron mobility” and “hole mobility”, extracted from the reported papers? If so, please provide the related references.
6. Does the “M” in Fig. 2 and Equation (8) present the same meaning? Please confirm.
7. Equation (1) is suggested to be deleted because it is unnecessary. In addition, Equation (2) is suggested to be transferred into Section 4.1.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 5 Report
Comments and Suggestions for Authorssee the attached file.
Comments for author File: Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsThe answers to the questions and comments are convincing. I therefore give a favorable opinion for the acceptance of this work.
Author Response
Thank you for your message.I'm glad to hear that it can be published in its current form. Your support is valuable to me. If there are any further steps or requirements needed for publication, please let me know.
Reviewer 2 Report
Comments and Suggestions for AuthorsI think the authors did not understand my comments. They keep comparing their results we Silicon detectors not GaN-based UV detectors. My review conclusion is the same as before.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
