Optics of Inhomogeneous Thin Films with Defects: Application to Optical Characterization

Round 1

Reviewer 1 Report

In this review report, the authors discussed the optics of inhomogeneous thin films, over layers, thickness non-uniformity, boundary roughness, and uniaxial anisotropy. Also, they had applied the theoretical approaches like Mueller matrix for local thickness distribution or polynomial formulation for the thickness non-uniformity, scalar diffraction theory and Rayleigh-Rice theory or their combination for boundary roughness and Yeh matrix formalism for uniaxial anisotropy. The authors mentioned that the optical techniques are important to characterize thin films as they stated in the manuscript. This review article could be interesting for the reader of the thin film field or related scientific community. Therefore, I recommend the paper for publication, I have no comment.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Manuscript ID coatings-1039783

Title Optics of inhomogeneous thin films with defects: Application to optical characterization

Authors: Ivan Ohlídal, Jiří Vohánka, Martin Čermák

The article submitted for review is of certain interest to the scientific community.  It can be seen that the authors have made a comprehensive literature study. The topic is very current due to the growing interest in the field optics of inhomogeneous thin films.

Undoubtedly, the issue is relevant and should be of interest to the science community.

However, the authors do not underline what kind of scientific novelty brings their manuscript to the literature.

Additionally, the text is written in a non-orderly way, it was not easy to read and it may be difficult to find the relevant information in the review, with redundant points and superficial argument.

Moreover, it shows several shortcomings. The equations are not well numbering. A lot of equations are not numbered.

More than 50% from references are self-citations.

For the weakness mentioned above, I cannot recommend the publication of this paper in Coatings.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Manuscript number: coatings-1039783 Coatings MDPI (Review)

TITLE: Optics of inhomogeneous thin films with defects: Application to optical characterization

AUTHORS: Ivan Ohlidal, Jiri Vohanka, and Martin Cermak

The first review of the manuscript

Overall description of the manuscript

In the manuscript entitled “Optics of inhomogeneous thin films with defects: Application to optical characterization” by I. Ohlidal, J. Vohanka, and M. Cermak submitted as a review article to Coatings MDPI journal, the aouthors present discussion of a topic of optics of inhomogeneous thin films exhibiting defects consisting in transition layers, overlayers, thickness non-uniformity, boundary roughness and uniaxial anisotropy.

The introductory part is a good introduction to the topic and indicates the importance and a context of the issues included in the present manuscript. Next, the paper consists of theoretical part, which presents different (approximate) methods of theoretical investigations of (a) Inhomogeneous thin films without defects [such as: Wentzel–Kramers–Brillouin–Jeffreys (WKBJ) method, Approximate method based on using multilayer systems, Approximate method based on modification of recursive formulae of multilayer systems, Approximate method based on multiple-beam interference model] and (b) Inhomogeneous thin films with defects (following defects are discussed: Transition layers and overlayers, Thickness non-uniformity, Random roughness of film boundaries, Uniaxial anisotropy). This part presents comprehensive collection of the methods. Their presentations are compact but they include all necessary information and refers to literature which contains more details of discussed methods. The interested reader can find details of different issues raised in the submitted manuscript The third part is experimental and contains the comparison between theoretical description and some experimental results for SiOxCyHz exhibiting the complicated thickness non-uniformity and transition layer and inhomogeneous thin film of non-stoichiometric silicon nitride (SiNx) with random roughness of the upper boundary and uniaxial anisotropy. This part contains a new results and I am not sure if it is appropriate for the review article, which should not contain any new results, but rather present results published elsewhere and discussed them in the new perspective. However, the authors clearly indicates how the synthesis of the materials was performed and describes in detail the equipment, which they used for samples characterization. The last part is Conclusions.

I think that the paper fits the journal scope of Coatings. The English language in the manuscript is quite well. It can be understood even by the non-specialist in the field as it should be expended from a review article. The paper has 31 pages and includes 12 figures (equivalent of 3 and ½ of the page), 2 tables (equivalent to a half of a page) and 94 references 5 pages) – 22 pages of the text. The present manuscript includes rather a balanced, comprehensive and critical view of the research area, however the number of autocitations in the manuscript is quite large.

In my opinion, the Nevertheless, before the publication the Author should consider some improvements concerning the points listed below. In my opinion, the manuscript should be published after minor revisions accordingly to the points mentioned below.

Some specific comments for the authors that should be properly addressed:

1) The number of autocitations in the manuscript is quite large. I do not say that they are inappropriate, but maybe the authors could reconsider them and choose only the most important references. Maybe some references of other authors could be also added.

2) The third part (experimental) contains a new results and I am not sure if it is appropriate for the review article, which should not contain any new results, but rather present results published elsewhere and discussed them in the new perspective. Could at least authors justify this?

3) I strongly suggest to add at the end of the introduction section, the paragraph describing how the paper is organized. Such addition would be very helpful for the reader, because it is convenient, when the reader can know the content of the manuscript at the beginning (at least, it is useful for some of the readers). I think that this could improve the paper.

4) The authors could think about some paragraphs, which summarizes (concludes) the issues discussed in the manuscript. I see that there is a section entitled “Conclusions” but for me it is too much general and it should be at least in one or two paragraphs, which address the materials described previously and the theoretical methods included in the preceding part of the paper.

To sum up, I believe this paper will suitable for publication in “Coatings” MDPI journal as review article, after issues mentioned above will be resolved. In my opinion, the topic of the paper, which is strongly associated with current progress in thin-layers physics, is very current and interesting. Thus, I think that the review article, which is a brief introduction to this topic and discuss different aspects and issues is highly demanded by the scientific and engineer communities.

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

See attached .pdf.

Comments for author File: Comments.pdf

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

The authors answered to most of reviewer question.

The paper is now publishable if the editor agrees.