Metal-Free Catalytic Preparation of Graphene Films on a Silicon Surface Using CO as a Carbon Source in Chemical Vapor Deposition
Round 1
Reviewer 1 Report
The present article is devoted to the actual problem of creating high-quality silicon-based graphene films. The study was performed carefully. The article is written clearly, in good English. The results obtained indicate that the proposed method of depositing a graphene film using exposure of a silicon wafer in CO vapor at elevated temperatures is very promising technique. However, before the article is published, the authors have to answer a few questions and correct a number of inaccuracies.
1. What is the origin of the “grains” discussed in section 3.1? Why does the boundary between grains disappear as the temperature rises?
2. What means the “cloudy mist pattern” in Figure 1b? Could it be the result of poor photo quality?
3. The percentages of certain groups in section 3.2 should be organized in a table. In this case, descriptive text becomes unnecessary and authors can focus on interpreting the results.
4. Are the authors sure that the deconvolution of the XPS spectra (Fig.2) makes it possible to determine the percentage content of different groups with an accuracy of tenths of a percent? What is the error of the deconvolution procedure?
5. It is completely unclear how the thickness of the resulting graphene layer was determined.
6. The experiment presented in Section 3.4 undoubtedly gives an idea of the sequence of formation of SiO2 and SiC layers on the support surface during the process. Perhaps, one can make assumptions about the reactions leading to the observed result. However, according to the reviewer, it is premature to talk about the mechanism of the process on the basis of Figure 4 alone. What are the thermodynamic calculations which are mentioned in line 175? Is it known for sure that at (800-900)°C CO cracks with the formation of atomic oxygen? If so, please provide links to relevant publications. The same question arises regarding the cracking of CO at 1000°C with the formation of [C] and O2. Generally, in section 3.4 it is necessary to separate facts and more or less reliable suppositions.
7. Abbreviation CDV (chemical vapor deposition) appears for the first time in Abstract section without any explanation.
8. Seconds are denoted as “sec” (line 23).
9. The scale bars in Figure 1 are almost invisible.
10. The phrase “and the grain boundaries were present, not observed” (lines 109-110) is not clear.
English is quite acceptable
Author Response
The present article is devoted to the actual problem of creating high-quality silicon-based graphene films. The study was performed carefully. The article is written clearly, in good English. The results obtained indicate that the proposed method of depositing a graphene film using exposure of a silicon wafer in CO vapor at elevated temperatures is very promising technique. However, before the article is published, the authors have to answer a few questions and correct a number of inaccuracies.
1.What is the origin of the “grains” discussed in section 3.1? Why does the boundary between grains disappear as the temperature rises?
Reply: I am very grateful to your comments for the manuscript. With the increase of preparation temperature, the graphene grows continuously, the grain size increases, so the grain boundary ratio decreases gradually.
- What means the “cloudy mist pattern” in Figure 1b? Could it be the result of poor photo quality?
Reply: I am very grateful to your comments for the manuscript. It comes from a defects in the graphene that causes it to become less flat.
- The percentages of certain groups in section 3.2 should be organized in a table. In this case, descriptive text becomes unnecessary and authors can focus on interpreting the results.
Reply: I am very grateful to your comments for the manuscript. we have amended the relevant part in manuscript with red font.
Table 1 Elemental analysis of XPS
|
Sample(temperature) |
Si-C(at%) |
Si-O(at%) |
sp2-C(at%) |
X2 |
|
Binding energy(eV) |
283.5 |
103.5 |
284.7 |
|
|
1000℃ |
59.8 |
16.9 |
23.3 |
3.31 |
|
1100℃ |
56.8 |
12.1 |
36.1 |
7.02 |
|
1150℃ |
32.9 |
5.9 |
61.2 |
14.43 |
- Are the authors sure that the deconvolution of the XPS spectra (Fig.2) makes it possible to determine the percentage content of different groups with an accuracy of tenths of a percent? What is the error of the deconvolution procedure?
Reply: Thanks for the referee’s suggestion. According with your advice, we have amended the relevant part in manuscript with red font. In addition, XPS data fitting was performed according to XPSpeak software, and the fitting error x2 was controlled within 20.
- It is completely unclear how the thickness of the resulting graphene layer was determined.
Reply: Thanks for the referee’s suggestion. The Raman analysis results show that graphene has about 2 to 5 layers( according to the XPS analysis results in Section 3.2 of the manuscript), so the thickness of graphene was 1.7 nm(the number of graphene layers was 5, and the graphene interlayer distance is about 0.34nm).
- The experiment presented in Section 3.4 undoubtedly gives an idea of the sequence of formation of SiO2 and SiC layers on the support surface during the process. Perhaps, one can make assumptions about the reactions leading to the observed result. However, according to the reviewer, it is premature to talk about the mechanism of the process on the basis of Figure 4 alone. What are the thermodynamic calculations which are mentioned in line 175? Is it known for sure that at (800-900)°C CO cracks with the formation of atomic oxygen? If so, please provide links to relevant publications. The same question arises regarding the cracking of CO at 1000°C with the formation of [C] and O2. Generally, in section 3.4 it is necessary to separate facts and more or less reliable suppositions.
Reply: Thanks for the referee’s suggestion.CO will crack in the process of temperature rise, producing active carbon atoms and O atoms [[1] Bremmer G M, Zacharaki E, Sjåstad AO, et al. In situ TEM observation of the Boudouard reaction: multi-layered graphene formation from CO on cobalt nanoparticles at atmospheric pressure[J]. Faraday Discussions, 2017, 197(5).Dio: 10.1039/c6fd00185h]. The deposition of [C] could also originate from via the Boudouard disproportionation reaction [Grebenko A K, Krasnikov D V, Bubis A V, et al. High‐Quality Graphene Using Boudouard Reaction[J]. Advanced Science, 2022, 9(12): 2200217.Dio: 10.1002/advs.202200217; Chakrabarti A, Lu J, Skrabutenas J C, et al. Conversion of carbon dioxide to few-layer graphene[J]. Journal of Materials Chemistry, 2011, 21(26): 9491-9493.Dio: 10.1039/c1jm11227a].The reaction produces O atom,which will preferentially react with Si sheet to generate SiO2 [Liu Q, Gong Y, Wang T, et al. Metal-catalyst-free and controllable growth of high-quality monolayer and AB-stacked bilayer graphene on silicon dioxide[J]. Carbon, 2016, 96: 203-211. 10.1016/j.carbon.2015.09.075]，and the SiO2 will reacts with carbon atoms to form SiC, Thus, a composite layer of SiC and SiO2 is formed on the surface of the Si sheet, which can promote the growth of graphene. [Hackley J, Ali D, DiPasquale J, et al. Graphitic carbon growth on Si (111) using solid source molecular beam epitaxy[J]. Applied Physics Letters, 2009, 95(13): 133114.Dio: 10.1063/1.3242029; Thanh Trung P, Joucken F, Campos-Delgado J, et al. Direct growth of graphitic carbon on Si (111)[J]. Applied Physics Letters, 2013, 102(1): 013118.Dio: 10.1063/1.4773989].
- Abbreviation CVD (chemical vapor deposition) appears for the first time in Abstract section without any explanation.
Reply: Thanks for the referee’s suggestion. According with your advice, we have amended the relevant part in manuscript with red font
- Seconds are denoted as “sec” (line 23).
Reply: Thanks for the referee’s suggestion. According with your advice, we have amended the relevant part in manuscript with red font
- The scale bars in Figure 1 are almost invisible.
Reply: Thanks for the referee’s suggestion. According with your advice, we have amended the relevant part in manuscript.
- The phrase “and the grain boundaries were present, not observed” (lines 109-110) is
Reply: Thanks for the referee’s suggestion. According with your advice, we have amended the relevant part in manuscript with red font.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
1- The abstract must be contained the important gain results
2- In the SEM images, it was recommended to insert the HR-SEM, which was required to discuss the change on the topography and roughness. Also, the magnification information was not completely clear on them
3- It was recommended to support your result with EDX and/or mapping to check the purity of graphenes
4- Also, Where the XRD investigation
5- In XPS, please insert the zoon out binding energy to check the purity of the prepared materials
it was acceptable
Author Response
Response letter
May 16th, 2023
Dear the Editor,
Thank you very much for your letter dated on April 2th, 2023, and the referees’ reports. Based on your comment and request, we have made extensive modification on the original manuscript. Here, we attached revised manuscript in the formats MS word, for your approval. A document answering every question from the referees was also summarized and enclosed. A revised manuscript with the correction sections red marked was attached as the supplemental material and for easy check/editing purpose.
1.The abstract must be contained the important gain results
Reply:I am very grateful to your comments for the manuscript. The abstract has been revised and identified in red front in revised manuscript.
- In the SEM images, it was recommended to insert the HR-SEM, which was required to discuss the change on the topography and roughness. Also, the magnification information was not completely clear on them
Reply:I am very grateful to your comments for the manuscript. According with your advice, we have amended the relevant part in manuscript with red font.
- It was recommended to support your result with EDX and/or mapping to check the purity of graphenes
Reply: By using XPS analysis and Raman analysis, it has been possible to prove the presence of graphene on the surface of Si substrate, and further analyze the number of graphene layers and the degree of defect.Through XPS analysis, the existence of sp2 hybrid carbon and the obvious 2D Raman peak on the surface of silicon wafer, which both indicate the presence of graphene on the surface of silicon wafer.
- Also, Where the XRD investigation
Reply: Due to the existence of graphene thin layer on the Si substrate surface, the XRD detection depth is large, so the components detected are mainly Si elemental, which cannot characterize the composition and purity of graphene materials（Fig.1）.
Fig.1 XRD from 1100℃
- In XPS, please insert the zoon out binding energy to check the purity of the prepared materials
Reply: I am very grateful to your comments for the manuscript. The binding energy of Si-C bonds (283.5 eV), Si-O bonds (103.5 eV), and sp2-C bonds (284.7 eV) has been corrected in in revised manuscript with red front.
Author Response File: Author Response.pdf
Reviewer 3 Report
In this manuscript, L. Lintao et al. described “Metal-free Catalytic Preparation of graphenes Fimls on the Silicon Surface using CO as Carbon Source in Chemical Vapor Deposition,” in detail. Samples are properly characterized. However, at this stage there are still many problems and I therefore suggest a major review for this manuscript keeping in mind the following questions.
1) The title has a problem in the words “graphenes Fimls”. Both the grammar and spelling are wrong. It must be graphene Films.
2) The English language is very poor. The respected authors are encouraged to re-write the manuscript and correct all the spelling and grammar mistakes to attract more readers.
3) The term “the metal is evaporated….” Does not seem to be correct as metals are evaporated at high temperature which is not tolerated by graphene and graphene decompose at the high temperature required for metal evaporation.
4) The SEM images show highly agglomerated structure. Can the respected authors explain the reason? How will it be minimized?
5) Any abbreviation must be defined completely before its first appearance but in the manuscript abbreviations such as “SEM, CVD, etc have been used without proper definitions.
6) What is the difference between the XPS of free Si and the graphene occupied by Si?
7) Some very important article citations are missing in the XPS part of the manuscript.
i) https://doi.org/10.1007/s12274-016-1140-8
ii) https://doi.org/10.1515/zpch-2020-1778
8) The conclusion is written in points. This practice is carried out in review articles. For the research article, the conclusion is written as one paragraph containing all the findings.
English language is poor.
Author Response
Response letter
May 16th, 2023
Dear the Editor,
Thank you very much for your letter dated on April 2th, 2023, and the referees’ reports. Based on your comment and request, we have made extensive modification on the original manuscript. Here, we attached revised manuscript in the formats MS word, for your approval. A document answering every question from the referees was also summarized and enclosed. A revised manuscript with the correction sections red marked was attached as the supplemental material and for easy check/editing purpose.
in this manuscript, L. Lintao et al. described “Metal-free Catalytic Preparation of graphenes Fimls on the Silicon Surface using CO as Carbon Source in Chemical Vapor Deposition,” in detail. Samples are properly characterized. However, at this stage there are still many problems and I therefore suggest a major review for this manuscript keeping in mind the following questions.
1)The title has a problem in the words “graphenes Fimls”. Both the grammar and spelling are wrong. It must be graphene Films.
Reply: Thanks for the referee’s suggestion. According with your advice, we have amended the relevant part in manuscript with red font.
2) The English language is very poor. The respected authors are encouraged to re-write the manuscript and correct all the spelling and grammar mistakes to attract more readers.
Reply: Thanks for the referee’s suggestion. According with your advice, the language and presentation of the manuscript has been modified in manuscript with red font.
3) The term “the metal is evaporated….” Does not seem to be correct as metals are evaporated at high temperature which is not tolerated by graphene and graphene decompose at the high temperature required for metal evaporation.
Reply: Thanks for the referee’s suggestion. According with your advice, we have amended the relevant part in manuscript with red font.
4) The SEM images show highly agglomerated structure. Can the respected authors explain the reason? How will it be minimized?
Reply: The SEM images showed the morphology of graphene on the surface. At temperature of 1000℃, the nucleation rate of graphene was low, the grain size of graphene was small and incomplete. With the increase of preparation temperature, the growth of graphene was promoted, the size of graphene increased, so the quality of graphene was improved.
5)Any abbreviation must be defined completely before its first appearance but in the manuscript abbreviations such as “SEM, CVD, etc have been used without proper definitions.
Reply: Thanks for the referee’s suggestion. According with your advice, we have amended the relevant part in manuscript with red font.
6) What is the difference between the XPS of free Si and the graphene occupied by Si?
Reply: XPS can only detect Si , O and C(little adventitious C adsorbed on Si substrate)elements on the surface of free silicon(Fig. 1), while C, O and Si elements can be detected on the surface of Si with graphene film layer(Fig.2). Due to the thin number of graphene layers and defects on the surface of graphene, Si and O elements can be detected in addition to C elements.
Fig. 1 Free Si substrate
Fig. 2 Graphene-covered Si substrate
7) Some very important article citations are missing in the XPS part of the manuscript.
- i) https://doi.org/10.1007/s12274-016-1140-8
- ii) https://doi.org/10.1515/zpch-2020-1778
Reply: Thanks for the referee’s suggestion. According with your advice, we have amended the relevant part in manuscript with red font.
8) The conclusion is written in points. This practice is carried out in review articles. For the research article, the conclusion is written as one paragraph containing all the findings.
Reply: Thanks for the referee’s suggestion. According with your advice, we have amended the relevant part in manuscript with red font.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Dear Colleagues! I am satisfied with the corrections made. There is one moment left. The error of the deconvolution process (X2) should be described in the text and mentioned in the caption to the Table 1. Also, it is necessary to comment on the significant increase in the value of X2 when moving to a temperature of 1500C.
The English language of the authors is quite understandable.
Author Response
Response letter
May 23th, 2023
Dear the Editor,
Thank you very much for your letter dated on May 22h, 2023, and the referees’ reports. Based on your comment and request, we have made extensive modification on the original manuscript. Here, we attached revised manuscript in the formats MS word, for your approval. A document answering every question from the referees was also summarized and enclosed. A revised manuscript with the correction sections red marked was attached as the supplemental material and for easy check/editing purpose.
Dear Colleagues! I am satisfied with the corrections made. There is one moment left. The error of the deconvolution process (X2) should be described in the text and mentioned in the caption to the Table 1. Also, it is necessary to comment on the significant increase in the value of X2 when moving to a temperature of 1500C.
Reply: Thanks for the referee’s suggestion. According with your advice, we have amended the relevant part in manuscript with red font. XPS data of all samples (1000℃, 1100℃, 1150℃) were fitted using XPSpeak software with Lorentz-Gaussian function, and all the fitting results reached the optimal value. Due to the slight difference of XPS curve, the fitting result will be affected. At the temperature of 1150℃, although the error of deconvolution process(X2) is 14.7, it is still a relatively low value, so the result is reliable.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The paper can be accepted in the current form
Author Response
Response letter
May 23th, 2023
Dear the Editor,
Thank you very much for your letter dated on May 22h, 2023, and the referees’ reports. Based on your comment and request, we have made extensive modification on the original manuscript. Here, we attached revised manuscript in the formats MS word, for your approval. A document answering every question from the referees was also summarized and enclosed. A revised manuscript with the correction sections red marked was attached as the supplemental material and for easy check/editing purpose.
Reviewer 3 Report
Since the authors replied positively to remove all the shortcomings in the manuscript, I therefore, accept the publication of this manuscript.
Author Response
Response letter
May 23th, 2023
Dear the Editor,
Thank you very much for your letter dated on May 22h, 2023, and the referees’ reports. Based on your comment and request, we have made extensive modification on the original manuscript. Here, we attached revised manuscript in the formats MS word, for your approval. A document answering every question from the referees was also summarized and enclosed. A revised manuscript with the correction sections red marked was attached as the supplemental material and for easy check/editing purpose.
Author Response File: Author Response.docx
