Effect of High-Temperature Annealing on Raman Characteristics of Silicon Nanowire Arrays
Round 1
Reviewer 1 Report
Review of the manuscript
“Effect of high-temperature annealing on Raman characteristics 2 of silicon nanowire arrays”
by
The essence of the results obtained in the reviewed article is as follows. The authors grew silicon nanowires (SiNWs) on a silicon substrate. For the growth of these structures, the authors used the silicon etching method. Etching was carried out by two methods. When etching Si by the first method, at the beginning the silicon surface was covered with a thin layer of Ag from an AgNO3+HF solution. When etching according to the second method, at the beginning, an Au layer was applied to the substrate by ion sputtering. Then both structures were etched in a solution of a mixture of H2O2:HF:H2O. After this procedure, these structures were annealed at high temperature in an argon atmosphere. Before and after annealing, both structures were studied using a scanning scanning microscope and Raman spectroscopy. Based on these studies, the authors conclude about the mechanism of defect formation and the structure of the obtained SiNWs nanowires.
Remarks
1. 1. When reading an article, there is a feeling that the article consists of two separate parts. One part is the description of the experiment. The second part of the article attempts to explain the reasons for the shifts in the Raman lines obtained by the structures relative to the lines of untreated silicon. If the authors had accurately compared the magnitude of these shifts with each of the silicon defects on the surface of which SiNWs structures were formed, this would have been a very significant result. But there is no such result in this work. Using formula (3) in which the intensity of the Raman spectrum is a function of the asymmetry factors, the authors do not calculate them, but only qualitatively reason about the possible cause of shifts of the Raman lines with respect to pure Si. The authors simply list all possible causes of line shifts. There is no specific analysis of the effect of defects on the line shift in the work.
2. It is necessary to completely change the approach to this task. The material for research is very fertile. If you do research differently, then you can do a great job on these materials. In particular, already when Si is coated with an Ag layer in AgNO3+HF solution, chemical reactions of Si etching occur. For example, the interaction of HF with AgNO3 can lead to the formation of nitric acid, which together HF will etch silicon. When etching in Si, vacancies are formed that will merge into the pores. Naturally, places that are covered with metal will not be so etched as places free of coatings. It is not correct to compare surfaces coated with gold deposited by ion deposition with a surface coated with silver by chemical reaction. The silicon surface coated with silver during the chemical deposition of the coating becomes etched. This is clearly seen in Fig. 2a. Pores are clearly visible at the interface in silicon. Therefore, the structure of the Ag layer differs from the structure of the Au island film. Etching processes under various conditions have been studied well and for a long time on the example of etching of various materials. You just need to look at the literature on the branching of various materials, and not just these systems
5. The images of the surface of Au layers formed after annealing shown in Figure 4b should be made at the same scale as the surface before annealing (Figure 3b). The scale in these pictures differs twice, so it is difficult to say something about the change in the structure of the layer after annealing.
3. In general, the main essence of the comments boils down to the fact that it is not clear what new knowledge this work claims to present. From an experimental point of view, the data obtained is insufficient. There is no description of the chemical processes occurring during etching and annealing. The images of the surfaces were taken at different scales (for Au). There is no description of the etching mechanism even at a qualitative level. The theoretical analysis of Raman spectra is not specific. It cannot be specific, because it is not enough to use only Raman spectroscopy to analyze such a multifactorial process.
4. The article requires serious revision. In this form, it cannot be published in Coatings.
Comments for author File: 
Comments.pdf
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 2 Report
Dear Editor and Authors! Thank you for offering to read the article.
The article is undoubtedly devoted to an important scientific and practical topic - the development of new materials for energy conversion, the creation of sensors, etc. The article is quite similar to the topics of the journal and can be accepted for publication after appropriate additions and improvements. In my opinion, the experimental part is poorly described, and the discussion is overly presented.
Comments and questions:
1. Methods of electrochemical synthesis may also be reflected in the review of methods (10.3390/electrochem3040050; 10.1002/ange.201707064; 10.3390/app112210927 et al). It begs an explanation why the authors chose the etching method.
2. In the Experimental section, it is necessary to specify the qualifications, firms and countries of manufacturers of reagents and materials.
3. Is the silicon resistance tested by the authors or specified by the manufacturer?
4. Is it possible to oxidize silicon during nitrogen treatment?
5. Paragraph 2.2. In my opinion, an illustration of the operations performed and their variants should be given in this paragraph. This will help to better understand their purpose, their place in the synthesis chain, as well as the discussion of the results.
6. It is advisable to touch in more detail on the parameters of operations and the reasons for their choice. Even if they are defined in earlier works, it should at least be briefly noted here. Why were the etching parameters chosen (time, solution composition, temperature, duration, how were bubbles observed?, etc.) and processing (duration, temperature, atmosphere?)…
7. What is the roughness of silicon after pretreatment? Are there micrographs of the silicon surface before the deposition of noble metal particles?
8. Micrographs are clear in principle. However, are there micrographs in higher resolution? It is desirable to compare micrographs of different samples at the same magnification.
9. On lines 107-109, is it correctly reported that the coated areas of silicon were etched?
10. The discussion part requires structuring into sub-paragraphs.
11. The authors studied the properties only using Raman spectroscopy. Are there plans to study the operational characteristics of the samples obtained by other methods?
12. The final part suggests an analysis of the prospects of development in terms of stages and costs.
13. There are minor typos.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Authors present a research article focused on assessment of the effect of high-temperature annealing on Raman characteristics of silicon nanowire arrays. After carefully reading twice the paper I did not find much novelty on the paper or interest. Besides, I’ve found few details which convince me that I m not going to propose this paper to further revision or publication. I discourage to publish based on my comments below
My remarks:
1.- Authors already published a related-similar work in 2019, (doi:10.3390/coatings9020149) in which they already use the figure/experimental dat. i.e figure 1b of this paper compared with the 1B in the present paper. I really dislike this behavior when a researcher tries to use in several times/publications the same experimental data
2.- Reading carefully, there is a huge bibliography in the field during the last 4-5 years. Besides only in 2022 there is lot of references regarding this subject, but authors only include solely one reference of 2022 among their more than 30 references.
3.- Raman spectra are blurry, not normalized hard to understand author’s claims.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Review of the corrected manuscript
“Effect of high-temperature annealing on Raman characteristics 2 of silicon nanowire arrays”
by
Shanshan Wang and Yan Zhang
The authors have done a great job of rethinking their work. After the correction, this article is very good. This is a very good and strong job. It can be published in the presented form in Coatings.
Comments for author File: Comments.pdf
Reviewer 3 Report
ok
