Crosslinking Multilayer Graphene by Gas Cluster Ion Bombardment
and Zinetula Insepov 1,3,4,*Round 1
Reviewer 1 Report
Graphene nanopores can have potential applications in various technologies, such as DNA sequencing, gas separation, and single molecule analysis . Generating pores with precisely controlled subnanometer sizes is the key challenge in the design of a graphene nanopore device. Various techniques have been employed to punch nanopores in graphene sheets, including electron beam from a transmission electron microscope (TEM) and heavy ion irradiation . Using electron beam technique, Fischbein and Drndic drilled nanopores with the width of several nanometers and stable; but, this high cost method is not fully controllable at nanoscale. Russo and Golovchenko used energetic ion exposure technique to create nanopores with radius as small as 3 A. Zhao et al. indicated that energetic cluster irradiation was more effective in generating of nanometer-scale pores in graphene, because their much larger kinetic energy could be transferred to the target atoms. Recent experimental works have further confirmed that cluster irradiation is a feasible and promising way in the generation of nanopores. Numerical simulations have demonstrated that a nanopores of controlled sizes and qualities can be fabricated in a graphene sheet by choosing a suitable conditions of collision between nanocluster and graphene such as impacting cluster energy, cluster size, temperature and cluster species .
In the present study, computational and experimental results of irradiation of graphene and MLG with Ar gas cluster ion beams are presented. The irradiated samples were characterized by Raman spectroscopy and transmission electron microscopy (TEM). They show that irradiation of MLG with argon cluster ion leads to the crosslinking of its layers and the formation of nanopores in it.
The present paper is of interest for both experiments and fundamental physics of fabrication of pore production on multilayer graphene, so that the reviewer evaluate this paper is acceptable for publication on the journal
Author Response
The reviewer 1 did not suggest any modifications to the manuscript. We agree with the Reviewer's Comments and overall evaluation.
Reviewer 2 Report
see attached file
Comments for author File: 
Comments.pdf
Author Response
Reply to the reviewer 2 Comments:
Comment 1:
Page 5 line 147: in the discussion on the ID/IG ratio it is suggested the addition of a table including the ID/IG values of the un-bombarded and bombarded samples together with the literature reported data obtained with other approaches.
Reply to Comment 1:
A new Table 4 has been added that contains the ratios ID/IG of the un-bombarded and bombarded samples together with the literature reported data obtained with other approaches.
Comment 2:
Page 7 line 210: discussion/comparison with literature reported data obtained with other approaches could be useful to the readers.
Reply to Comment 2:
We have added the following text on Page 7 as a reply for the reviewer Comment 2:
Literature data on the sizes of nanopores in graphene structures vary greatly depending on their manufacturing method. For comparison, we cite several radiation methods, including gamma rays, focused beam, and ultraviolet. In particular, nanoscale pores with the average size of ∼3 nm were generated across 10 μm thick graphene oxide bucky-papers by gamma-ray irradiation in hydrogen [57]. Nanopores with a diameter of <10 nm have been fabricated in graphene layers by Fox at al. [58] using a low energy electron beam. Celebi at al. [59] used a focused ion beam to produce pores with diameters between less than 10 nanometers and 1 micrometer in double-layer graphene. In Ref. [60], pores with a diameter of 0.40 ± 0.24 nm in graphene were fabricated by ion bombardment and oxidative etching. In Ref [61] graphene nanomeshes with a pore size of ∼200 nm were obtained using UV-assisted photodegradation of the graphene oxide sheets.
We have also corrected affiliation for Sean Kirkpatrick and a US telephone number was added into the Corresponding author data.
Two more new reference sources [40, 41] were added to make literature data complete.
Author Response File: Author Response.pdf
