Round 1

Reviewer 1 Report

1.      The doping of GaAs is mentioned as 1 × 1019 cm−3  however the unit of doping is atoms- cm−3 authors need to make this correction.

2.      The abstract includes many unsubstantiated claims by author which put validity of study under question. Such as “These samples 10 were stored in a dry and dark environment for 26 years.”

3.       The paper suffers from technical issues to grammatical errors 

I therefore do not recommend article for further cosiderations.

The extensive improvement required

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

The authors reported the study of the photo response of doped and undoped GaAs aging process from 1995 to 2021. The experimental results are interesting and useful, but the paper is not written in a proper manner. The author should conduct a thorough check of the article's format, grammar, figures, and writing. Some of the experimental results are not illustrated well either. I suggest it should be reconsidered after a major revision.

1)       In line 50, can the authors describe a more detailed environment? Since different environment leads to different aging mechanism.

2)       In line 57-59, can authors provide the 1995-year experimental data that characterizes the doping concentration?

3)       From line 89 to line 91, the authors did not explain clearly the different changing trend of two zones. A more detailed mechanism description such as which band corresponds to which defects, should be added.

4)       In line 127, there seems wrong grammar expression in "between they".

5)       From line 130 to 131, the authors should clarify the relations between the peak position and crystallinity and the physics behind it.

6)       In line 145, the authors should provide evidence to prove the change was due to As vacancies.

7)       Please keep the same font style and size in all the equations.

Extensive editing English language is required.  

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The manuscript studies the effect of epitaxial aging of GaAs with and without Ge and Sn dopants for a period of over 20 years. The sample was exposed to the environment and analyzed using photoluminescence (PL) and photo reflectance (PR), which I find interesting to discuss. However, after reading the article carefully, we have concluded that the article has shown effort. However, it still needs some changes before it is ready to be published.

1.           First and foremost, the abstract section has shown a clear statement of the problem with a comprehensive analysis, however, the author does not propose a solution to the issue. Then, please also explain the benefits of this work extending to its use in industry.

2            In the results and discussion section, Figure 2 shows that the sample with a dopant concentration of 1E17 cm-3 appears to be the best in terms of crystallinity, however further dopant concentrations have not been thoroughly elucidated. Please explain the mechanism that occurs for higher concentrations.

3.           Please tabulate all the values in Table 2 properly and appropriately. It is quite difficult to understand in the current state.

4.           In the result and discussion section, page 6, the author claimed “The undoped GaAs sample did not give an observable photoreflectance signal because no change in reflectance was resolved, possibly due to a high surface electric field caused by the vacancies.” Such a statement is rather wild and not convincing, please explain further and support it with a few references.

none

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Reviewer Report:

Manuscript ID: applsci-2660313

Title: Study of the photoresponse of doped GaAs with aging

This article is devoted to studying the photo response of of epitaxial samples of GaAs doped with Ge and Sn. The studied samples were stored for 26 years.

In my opinion, the results are important and useful because the doped semiconductors such GaAs are strongly required in many applications.

Before accepting this manuscript, I have several remarks to improve the quality of the work

1- the consecutive references in the introduction part such as [1], [2] and [3], [4] must be written in this manner: [1,2] and [3,4] according the criteria of the journal. Check again this notation and verify the other references in the introduction part.

2- In the abstract, the authors said that the samples of GaAs are doped with Ge and Sn up to 1 × 10¹⁹ cm⁻³. It is better if the authors justify this choice of doping concentration.

3- In order to give importance to their work, I suggest that the authors indicate with more details the utility of their works in technological point view.

4- there are many grammatical errors. I suggest that the authors revise the entire text.

must be improved

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Acceptable 

English Grammer need to be checked

Reviewer 2 Report

The authors have addressed all the corresponding issues. I recommend its publication in present form.