Module 10: The manuscript describes a new "Super-clean" method for graphene growth using Chemical Vapor Deposition (CVD). In general, the manuscript is suitable for publication. However, the authors should consider the following comments below

*The aim of the manuscript is clear, the title is concise and can be directly associated with the results obtained by the authors;

*The size of the Abstract is good, usually around 150 words is appropriate for an Abstract of Nature Communications. The authors used two sentences to describe the hudles to be overcome in graphene-related materials and the main discovery described later in the manuscript;

*The number of the references are quite good and were not included with no reason. However, the authors missed so many important and recent references in the field of research of fabrication of graphene using CVD. I could list some of them which the authors could consider. Also, the authors should revisit some of the main important papers in the literature that focus on minimize the effects of metal/metal oxide and also polymer particles on to graphene monolayer:

• https://pubs.acs.org/doi/abs/10.1021/acsnano.5b01261 • https://pubs.rsc.org/en/content/articlehtml/2016/cs/c6cs00136j • https://onlinelibrary.wiley.com/doi/full/10.1002/celc.201800934

*The authors described the state-of-art very clear in the introduction with some of the appropriated references and a direct connection with the topic covered in the manuscript;

*The methodology is clear and reliable, each detail in the Methods section described appropriately for reproduction, variables and appropriate units (SI);

*The data shown is clear for the readers of Nature Communications. The schemes, figures, also the numbers and scales are very clear and are not blurred. I suggest that the authors improve the size of the scale in the insets of Figures 3d and Figure 4a,c. The description of the results are clear along the text with the general and specific results well described with no misunderstood about the main message of the paper;

*The size of conclusion is appropriate and concise towards the elucidation of surface contamination of CVD-grown graphene process. Moreover, the manuscript opens new pathways for fabrication of graphene single devices for a broad range of applications;

*In general, the description of the manuscript is consistent and appropriate for publication in a very important Journal like Nature Communications. Some relevant point should be addressed: (i) The explanation about the reason, origin of contamination is very well described, although the authors missed some recent and very important references in literature; (ii) the description of the new methodology and strategy used to overcome this problem was efficiently perform.

• Minor Points to be consider by the Authors prior of publication of the manuscript:

• Revisit the literature and consider the most recent and relevant papers in the field of graphene monolayer which covers the main problems and strategies to overcome the contamination inherent to CVD;

• Improve the size of the inset figures 3d and 4a,c.