Effect of Pulsed Light Irradiation on Patterning of Reduction Graphene Oxide-Graphene Oxide Interconnects for Power Devices

Round 1

Reviewer 1 Report

In this work, Choi and coworker presented an investigation on photo induced reduction of graphene oxide for patterning of reduced graphene oxide-graphene oxide patterns on graphene oxide film. By carefully reading, I found the following should be addressed before the manuscript can be considered further.

• It is well accepted that r-GO stands for reduced graphene oxide, that is the reduction product of graphene oxide. The authors should correct this throughout the manuscript.
• Language of the manuscript should be polished further. There are many typos and grammar mistakes and these should be corrected before resubmission.
• Photo induced reduction of graphene oxide has been investigated for about 10 years. There should be many publications concerning this topic. It would be nice if milestones in this field and related works can be cited and compared together.
• On page 2, starting from line 61, the authors claimed “In this study, it make to graphene line of damage free by understanding 61 pulsed energy and photo catalyst reaction. GO to the instantly irradiating strong light 62 energy method using a pulsed system such as camera xenon flash.” This should be improved.
• I didn’t see any evidence for “We have confirmed through previous experiments that a large damage caused by 120 excessive thermal energy of a 0.2 μm thick GO film. For instance, the experiment was 121 performed with 0.45 um films.”. At least a citation should be made here.
• Would the film thickness impact the photoreudction at the um level? It would be interesting if the authors can expand the discussion on this.
• I didn’t see any evidence for the author to distinguish the photothermal reduction from photocatalyzed reduction of graphene oxide for mechanism investigation. Therefore, the claim in the abstract “A mechanism of partial GO reduc- 14 tion by pulsed photon energy is identified for preparing patterned rGO-GO film.” should root on further evidence or citations.
• Though the results may sound interesting for technology investigation, it should give a detailed description on the light source, such as wavelength and energy distribution, etc, merely the power is not enough.
• It would be more interesting if the authors can distinguish the impact of photothermo reduction from catalyzed reduction, and also highlights the impact of light source on the photoreudction of graphene oxide.

 

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

In the submitted manuscript, the authors report on laser patterning reduced graphene oxide layer substrates for developing better interconnect solutions.

In general, the scalable formation of highly reduced GO and graphene films is crucial to the development of graphene-based devices and laser-irradiation-based patterning will significantly push forward the current status quo. The topic studied, the novel synthesis procedure discussed, and the quality of the experiments are good, however, it lacks in-depth analysis for the represented area of graphene-based electronics. My main concerns regarding the manuscript are mentioned below:

1. The method being utilized is laser irradiation, which has been systematized for some time for amorphous silicon (a-Si) (Physical Review Letters, 49(3), p.219) and amorphous carbon (a-C) (ACS Applied Materials & Interfaces 12 (1), 1330-1338) films to achieve phase transformation into crystalline counterparts. The introduction is lacking as herein, only laser patterning of pre-existing graphene is discussed. However, there have been recent reports regarding one-step patterning and synthesis of graphene and graphene oxide films by employing laser-induced thermal reduction (Carbon 2013, 52, 574−582) (J. Phys. Chem. Lett. 2010, 1, 2633−2636) and melt driven processing (Carbon2019,153, 663-673) (ACS Appl. Mater. Interfaces 2019, 11, 27, 24318-24330).
2. Please explain what laser has been employed to perform laser patterning and the relevant laser impact spot size. 
3. As the analytical methods have shown, the thin graphene films were transferred via Hummer’s method, resulting in thin films with poor conduction characteristics due to intrinsic topological defects. Some high-resolution SEM images should be presented for analyzing the number of wrinkles before and after laser irradiation processing.
4. From the Raman spectroscopy results, it is unclear if the authors have formed graphene, or heavily reduced graphene oxide to begin with. The high I_D/I_G ratio in the green line in Figure 6 suggests there might be some oxygen in the laser annealed samples. Even to ascertain if D, D’ or G* sub-peaks are present, the authors need to perform high-resolution Raman spectroscopy acquisitions and highlight the data revealing the same. I suggest performing some high-resolution XPS measurements near the O1s and C1s peaks to determine the oxygen content in these films, prior to and after laser treatment.
5. In the case of laser annealed samples, the authors should report line-scans of data, rather than a single spectrum, to show consistency in their laser processing technique. It would be interesting to perform some finite element simulations to analyze the temperature-time profiles for these films on laser irradiation.
6. To support their conclusions about a negligible deterioration in the quality of graphene oxide films on laser patterning, the authors need to perform temperature-dependent resistance measurements as a function of laser irradiation energy densities.
7. A suggestion would be to go ahead and analyze the dominant contributions towards electron conductivity in these films and the mechanism being followed (ES-VRH or Mott-VRH) and if there is any noticeable change in fitting curves on laser patterning of these films.

These concerns need to be addressed before publication in an archival journal like MDPI Coatings.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

This work investigates the partial GO reduction by pulsed photon energy and by photo thermal reduction methods for preparing patterned rGO-GO films. The patterned films were characterised by several techniques, FE-SEM, Raman spectroscopy, sheet resistance.

The work is interesting addressing a critical topic of current technology.

The introduction should be updated with more recent reviews on the subject and the relevance of the present work compared with the state of the art. The English is poor and it impairs the overall quality of the work.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I am sorry that I cannot recommend publication of the manuscript in its current form. In this revision, the authors didn't take the chance to response the comments of the reviewers carefully. The following concerns remain not addressed.

1. I didn’t see any evidence for the author to distinguish the photothermal reduction from photocatalyzed reduction of graphene oxide for mechanism investigation. Therefore, the claim in the abstract “A mechanism of partial GO reduc- 14 tion by pulsed photon energy is identified for preparing patterned rGO-GO film.” should root on further evidence or citations.
   2. Though the results may sound interesting for technology investigation, it should give a detailed description on the light source, such as wavelength and energy distribution, etc, merely the power is not enough.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The author's have responded to all my queries and have made necessary amendments. I recommend further publication. 

Author Response

Thank you very much for the reviewer comments.