Growth of Highly Transparent Amorphous Carbon Films Using Beam Plasma Source
Round 1
Reviewer 1 Report
107-109 Please give an overall molecular rationale for the higher energy ion bombardment which translates into higher hydrogen incorporation.
Table 1. Density is strictly proportional to power, however, Young´s modulus is not, please explain why.
Figure 7 and Table 2. The surface roughness fluctuates with power, should not it be proportional to it?
Author Response
Dear Reviewers,
Thank you for your helpful comments concerning our manuscript entitled “Growth of Highly Transparent Amorphous Carbon Films Using Beam Plasma Source”. Those comments are valuable for improving the manuscript. We have read your comments carefully and have implemented changes or explanations accordingly. Revised parts are highlighted in yellow throughout the revised manuscript.
- 107-109 Please give an overall molecular rationale for the higher energy ion bombardment which translates into higher hydrogen incorporation.
Response: An explanation based on a stronger dissociation of precursor molecules has been added to the text together with a recently published paper that included the ion energy functions under different RF power/voltage. (page 3)
- Table 1. Density is strictly proportional to power, however, Young´s modulus is not, please explain why.
Response: An explanation based on sp3/sp2 bonds and hydrogen incorporation has been added to the text (page 4).
- Figure 7 and Table 2. The surface roughness fluctuates with power, should not it be proportional to it?
Response: We observed that the changes in roughness as a function of the RF power were not significant. We added a paragraph to discuss this finding. (page 4)
Author Response File: 
Author Response.docx
Reviewer 2 Report
this work reports that the single beam plasma source was used to deposit hydrogenated amorphous carbon (a- 10 C:H) coatings at room temperature. The goal is to demonstrate the feasibility of low-temperature growth of highly transparent and dense a-C:H films with moderate Young’s modulus. After read all the manuscript, I suggest that the author should revise the article before the acceptance.
1. ‘RF’ in abstract should be given the full name;
2. The layout, especially for the figure of all the manuscript should be improved, Table 1 should be in the same page.
3. Figure 3 and Figure 4 should be integrated into a graph as Figure 4.
4. In figure 3, the authors said ‘It can be seen that the deposition rates increased almost linearly with the RF power because a higher RF power resulted in higher plasma density’, a higher ion source RF power of 50 and 60 should be added, or the deposition rate for every 5 W should be added. Three points do not ensure its linear relationship, it is better to provide five points.
5. Results and Discussion part is very short, such as from figure 2 to figure 4, there is only one short paragraph, at least the authors should explain the figures more clearly.
6. In reference 12, there is no page number for it. In addition, all the references are years ago, is there any recent work in this field?
Comments for author File: Comments.docx
Author Response
Dear Reviewers,
Thank you for your helpful comments concerning our manuscript entitled “Growth of Highly Transparent Amorphous Carbon Films Using Beam Plasma Source”. Those comments are valuable for improving the manuscript. We have read your comments carefully and have implemented changes or explanations accordingly. Revised parts are highlighted in yellow throughout the revised manuscript.
This work reports that the single beam plasma source was used to deposit hydrogenated amorphous carbon (a- 10 C:H) coatings at room temperature. The goal is to demonstrate the feasibility of low-temperature growth of highly transparent and dense a-C:H films with moderate Young’s modulus. After read all the manuscript, I suggest that the author should revise the article before the acceptance.
- ‘RF’ in abstract should be given the full name;
Response: Changed to radio frequency (RF) in abstract.
- The layout, especially for the figure of all the manuscript should be improved, Table 1 should be in the same page.
Response: Some overall adjustments have been made to the position and format of tables and figures.
- Figure 3 and Figure 4 should be integrated into a graph as Figure 4.
Response: Previously Figure 3 and 4 are now Figure 2a and 2b. All the other Figure numbers were adjusted accordingly.
- In figure 3, the authors said ‘It can be seen that the deposition rates increased almost linearly with the RF power because a higher RF power resulted in higher plasma density’, a higher ion source RF power of 50 and 60 should be added, or the deposition rate for every 5 W should be added. Three points do not ensure its linear relationship, it is better to provide five points.
Response: The effective cross-section area of this plasma source is only ~1.1 cm2. Therefore, 40 W is already a very high power density. We fully agree with the reviewer that three points do not ensure a linear relationship. Since the purpose of this study is to determine the deposition rates under each power level to eventually produce the same film thickness of 100 nm for the comparison of optical transmittance and reflectance, we deleted the statement “almost linearly” from the text in line 105/106.
- Results and Discussion part is very short, such as from figure 2 to figure 4, there is only one short paragraph, at least the authors should explain the figures more clearly.
Response: We completely agree with this remark, hence, we added more discussions and explanations throughout the text.
- In reference 12, there is no page number for it. In addition, all the references are years ago, is there any recent work in this field?
Response: Page numbers for reference 12 (now 13) were added.
We have selected 10 recent references (ref. 3, 4, 6, 19, 20, 21, 22, 23, 29, 30) published in the years 2018-2021.
Author Response File: Author Response.docx
Reviewer 3 Report
This article is devoted to the growth of transparent carbon films on silicon and glass by plasma sputtering. A technique has been developed to obtain sufficiently transparent coatings with a thickness of ~100 nm, which is very important for various applications. Nevertheless, the article contains practically no results of the obtained films except for measurements of Young's modulus, density and light transmission coefficient. As a result, it is impossible to understand what kind of carbon was obtained? What is its predominant hybridization, sp3 or sp2, is it similar to diamond-like carbon or not? What is the Raman spectrum of the obtained samples, what is the ratio of diamond and graphite peaks in it, etc. What does the dielectric function of the sample look like as a function of wavelength? Due to the lack of this information, the article makes no attempt to make sense of the results obtained. In particular, there is no explanation of what the transparency of the obtained films is related to. With hydrogen, or not?
Therefore, the article needs to be improved. It is necessary to perform a number of simple studies, such as Raman spectrum study, ellipsometric spectrum study, perhaps other studies related to the bond structure of the grown carbon. It is also necessary to supplement the article with a discussion and comprehension of the results, not just a statement of the fact of obtaining a carbon film.
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Author Response
Dear Reviewers,
Thank you for your helpful comments concerning our manuscript entitled “Growth of Highly Transparent Amorphous Carbon Films Using Beam Plasma Source”. Those comments are valuable for improving the manuscript. We have read your comments carefully and have implemented changes or explanations accordingly. Revised parts are highlighted in yellow throughout the revised manuscript.
This article is devoted to the growth of transparent carbon films on silicon and glass by plasma sputtering. A technique has been developed to obtain sufficiently transparent coatings with a thickness of ~100 nm, which is very important for various applications. Nevertheless, the article contains practically no results of the obtained films except for measurements of Young's modulus, density and light transmission coefficient. As a result, it is impossible to understand what kind of carbon was obtained? What is its predominant hybridization, sp3 or sp2, is it similar to diamond-like carbon or not? What is the Raman spectrum of the obtained samples, what is the ratio of diamond and graphite peaks in it, etc. What does the dielectric function of the sample look like as a function of wavelength? Due to the lack of this information, the article makes no attempt to make sense of the results obtained. In particular, there is no explanation of what the transparency of the obtained films is related to. With hydrogen, or not?
Therefore, the article needs to be improved. It is necessary to perform a number of simple studies, such as Raman spectrum study, ellipsometric spectrum study, perhaps other studies related to the bond structure of the grown carbon. It is also necessary to supplement the article with a discussion and comprehension of the results, not just a statement of the fact of obtaining a carbon film.
Response: We appreciate all the comments and suggestions, which are exactly what we plan to do in the next step. The main purpose of this work is to demonstrate the capability of a single beam plasma source recently developed by our team. This plasma source was initially developed for enhancing magnetron sputtering as we reported in a recent paper (J. Phys. D: Appl. Phys. 55 (2022) 395202). We believe it is interesting to validate its capability for PECVD as well. In response to the reviewer’s suggestion on the carbon film composition and bond structure, we did XPS analysis and the data was added. The results confirmed the existence of sp2 and sp3 C-C bonds in the films. (pages 3-4)
Author Response File: Author Response.docx
Round 2
Reviewer 2 Report
it should be accept
Reviewer 3 Report
The authors have corrected all comments, the article can be published in its present form
