Formation of Graphite-Copper/N-Silicon Schottky Photovoltaic Diodes Using Different Plasma Technologies

Round 1

Reviewer 1 Report

The authors have reported “Formation of Copper/Graphite/N-Silicon Schottky Photovoltaic Diodes Using Different Plasma Technologies”. This work mainly focuses on the comparison of the morphology of the copper-graphite-based photodiodes that were prepared using two different layer formation techniques (magnetron sputtering and plasma spraying) and then studies the effect of morphology on the yield of the devices. The authors have demonstrated that the efficiency of photodiodes using magnetron sputtering is much higher than that using plasma spraying. In general, this is an interesting work in this field of research. The manuscript is well written. I recommend its publication in Energies after improving the following details.  

1. The XRD peaks providing are too details in the abstract and conclusion section.
2. The authors are suggested to compare Fig. 1f and Fig. 2e, both films are 100% Cu but obtained using different methods. Plasma is also generated during magnetron sputtering to collect the film of the target in the substrate. Why the crystal morphology is so much different?
3. The corresponding Miller indices of Cu for XRD peak positions should be corrected.
4. The authors are suggested to update the Fig. number serially throughout the manuscript.
5. The authors are suggested to follow some energy-related works: Nanoscale Adv., 2019,1, 1791-1798; Adv. Opt. Mater. 0, 1900916 (2019).
6. Overall, the manuscript is well written. However, there are some typos or jumbled sentences that should be corrected.

Author Response

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Reviewer 2 Report

In this work Kavaliauskas et al. deal with formation of Schottky photovoltaic diodes by employing plasma spray technology and magnetron sputtering. The authors characterize the quality of the material by Scanning Electron Microscopy and X-ray diffraction. Then, they test the electric characteristics of the diodes. Important finding is that the efficiency of Schottky diodes formed using magnetron sputtering is on average 61 times higher than that of Schottky diodes formed using plasma spraying technology. The work is interesting. However, presentation needs improvements. A few comments:

*             In Fig. 2e the island formation reminds me of metal silicide formation than net metallic Cu. Many metals form easily silicides when they are deposited on Si by sputtering even at room temperature. The presence of graphite surfactant could facilitate these nanostructures to form. Could the authors provide some comments on that, see also refs. [1-4]?

 *            Why Cu shows a peak at 2theta = 22 deg, XRD Figure? Should n t the 43.6 be the Cu(111), 50.5 Cu(200). Is it a problem with labeling the diffraction peaks?

*             Fig 2 is the second SEM Figure. Then XRD Figure is again labeled as Fig. 2. So Fig. labeling should change with Fig. 3 being the XRD etc.

1. A. Mogilatenko et al., Passivation of Si(0 0 1) by the surfactant Sb and its influence on the NiSi2 growth. Journal of Crystal Growth 283, 303–308 (2005).
2. N. Vouroutzis et al., Growth of β-FeSi₂ particles on silicon by reactive deposition epitaxy Journal of Alloys and Compounds 448, 202-205 (2008).
3. A.M. Thron et al., Structural changes during the reaction of Ni thin films with (1 0 0) silicon substrates. Acta Materialia 60, 2668-2678 (2012).
4. P. Poulopoulos et al., Journal of Surfaces and Interfaces of Materials 2, 161–165 (2014).

Author Response

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Reviewer 3 Report

Improve the bibliographic review, with citations from 2020 and 2021.
Adjust the separations between text and tables.
Unify the text size of the figures.
Discuss the results contrasting them with those indicated by other authors.

Author Response

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Round 2

Reviewer 1 Report

This version of the manuscript is suitable for publication in Energies. No further revision is required.

Reviewer 2 Report

The authors have improved their presentation and show new findings based on XRD. I have no more criticism.