Electronic Structures of Molecular Beam Epitaxially Grown SnSe₂ Thin Films on $\sqrt{\mathbf{3}}\mathbf{\times }\sqrt{\mathbf{3}}$-Sn Reconstructed Si(111) Surface

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Main Question:
The research investigates the electronic structures of SnSe2 thin films grown on a √3-Sn reconstructed Si(111) surface. The study shows how the electronic structures and interfacial properties of SnSe2 differ between monolayer and multilayer when grown on a √3-Sn reconstructed Si(111) surface. The main findings were obtained through techniques such as molecular beam epitaxy (MBE), scanning tunneling microscopy (STM), X-ray photoemission spectroscopy (XPS), and angle-resolved photoemission spectroscopy (ARPES).

Originality and Relevance:
This study is highly original and relevant, addressing a specific gap in understanding how interfacial charge transfer and structural phase transitions influence the electronic properties of SnSe2 when grown on silicon substrates. This knowledge is crucial for optimizing SnSe2 applications in 2D electronic devices.

Consistency of Conclusions:
The conclusions are well-supported, addressing the main research question by demonstrating successful SnSe2 growth and interfacial charge transfer effects, aligning with the presented data on electronic structure changes.

Assessment:

The work is of high quality; I recommend it for publication after minor changes.

 

Possible further improvements

Methodological Improvements:
Enhancements could include additional cross-sectional transmission electron microscopy to confirm atomic layer alignment and potential strain distributions, as well as further temperature-dependent studies. At least a small discussion on possible strain in the material should be added.

Scientific Improvements:
Further experiments exploring alternative substrate preparations or additional doping mechanisms could provide deeper insights into tailoring SnSe2’s electronic properties for specific device applications. From the device point of view, what is the relevance of using Si substrate? Which device could be made with SnSe2/Si. What other substrates would be interesting from the technological applications point of view?

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Authors report on the fabrication of highly oriented crystalline layers of dichalcogenides (SnSe₂) on specially designed Si substrates modified with Sn. The layer was synthetized by two-steps molecular beam methodology monitored in-situ. Chemical composition was analyzed by XPS while structural characterization was performed primarily with Reflection high-energy electron diffraction. The energy band structure is discussed in depth to propose future electronic applications. The work is novel, thoroughly presented regarding the methodologies and characterization and within the scope of the collection. There are some changes and questions to be addressed before considering for acceptance:

• Do the authors claim that the films have superior electronic proprieties towards the proposed applications (electronic devices, sensors, etc)? If so, they should include a detailed discussion on how the results reported can be understood in that context, as to better adapt the text to the scope of the Applied Sciences journal.
• Transition metal chalcogenides are prone to oxidation in air. Did the authors study stability towards oxidation? Does the XPS allow for discussion of this aspect?
• The text should be revised to double check if all Acronyms and abbreviations are discussed in the first introduction.
• The conclusion section should also discuss what are the advantages of the novel methodology proposed compared to present methods in literature to obtain monolayers of SnSe₂
• What do authors mean by Sn being low toxic when they mention it in the introduction? The element itself, the most common compounds, SnS2? Authors should revise this statement.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The new version can be accepted.