Advances in Nanoparticle-Based Fabrication Techniques for Infrared Detectors: A Comprehensive Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This review provides a broad overview of nanoparticle-based fabrication techniques for infrared detectors, covering synthesis, surface engineering, deposition methods, and device architecture. The topic is timely, particularly in light of increasing research efforts toward scalable fabrication routes for infrared detectors with reduced cost and improved integration compatibility. The manuscript provides comprehensive coverage, features a clear logical structure, and demonstrates strong relevance to cutting-edge research as well as engineering applications. However, several issues should be further addressed before the manuscript can be considered for publication.

1. The notation for detectivity should be standardized throughout the manuscript. The manuscript defines detectivity (D*) in the Abstract and further introduces specific detectivity (D*) in Section 3.3. However, in Section 2.1, the manuscript reports performance as “D > 10⁹ Jones,” and Tables 4-6 also use the notation D instead of D* in several entries. Since specific detectivity is a key performance metric for infrared detectors, the notation should be used consistently throughout the manuscript to avoid confusion. In addition, on page 12, the formula for specific detectivity (D*) should be further verified, it should likely be . The authors are encouraged to carefully check and unify the terminology and all symbols in both the main text and tables.
2. Representative HgTe CQD device architectures could be further supplemented. In addition, the current discussion mainly focuses on single-pixel devices. The authors may also refer to recent reports on CQD array architectures to provide a more comprehensive overview of the current progress in this field.

3. All figures should be carefully checked and refined to improve readability. Multiple spelling errors are observed.

4. It is recommended to add critical analysis after the tables. For example, the paragraphs related to Table 2 mainly present a flat summary of the literature results. A “cross-comparative analysis section” could be added (rather than only the table).

5. The conclusion section could be further condensed to emphasize the key takeaways and future perspectives more clearly.

Author Response

Dear Reviewer,

thank you very much for your detailed and insightful comments. They have helped us tremendiously to carefully revise our manuscript. All changes in the manuscript are higlighted in yellow. Please find attached a list of point-by-point responses to your comments.

Kind regards,

AXEL KLEIN

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript provides a broad overview of nanoparticle-based fabrication techniques for infrared photodetectors, covering colloidal quantum dots, plasmonic nanoparticles, low-dimensional nanostructures, deposition and patterning strategies, device architectures, performance benchmarks, and future research directions. The topic is timely and relevant to the readership of Inorganics, particularly given the rapid development of solution-processable infrared detector materials and their potential for low-cost, large-area, and CMOS-compatible imaging systems.

The manuscript is generally well organized and contains a useful collection of tables and schematic figures. However, in its current form, the review is weakened by several major issues: insufficient critical synthesis, possible reference mismatches, uncritical reporting of extreme performance values, inconsistent notation and equations, and concerns regarding the quality and scientific reliability of AI-generated figures. Substantial revision is required before the manuscript can be considered for publication.

 

 Major Comments

1. AI-generated figures require substantial revision and author verification

The manuscript states that the schematic and conceptual figures were generated using ChatGPT with an integrated AI-based image generation tool. While AI-assisted illustration may be acceptable if fully disclosed and rigorously checked, several figures appear to contain distorted, illegible, or scientifically meaningless text fragments. For example, the roadmap-style figures include labels that are difficult to read or appear nonsensical. This is a serious presentation and scientific-integrity concern, because schematic figures in a review article should accurately guide readers rather than introduce ambiguity.

The authors should replace the AI-generated figures with professionally redrawn, author-verified schematics. Every label, arrow, material name, device structure, and mechanism should be checked manually. The authors should also clarify which figures contain AI-generated elements, what level of human editing was performed, and whether the use of AI-generated images complies with the journal’s editorial policy.

2. Reference accuracy and relevance must be thoroughly audited

Several citations appear to be insufficiently matched to the claims they support. For instance, Reference [123] is cited in the context of graded heterojunction or bulk-barrier structures for dark-current suppression, but the listed reference concerns hole subbands in quantum wells using the Luttinger–Kohn Hamiltonian. Similarly, References [74] and [75] are used to support spin-coating and electrophoretic-deposition claims, but they appear to refer to aerosol-jet printing of graphene/carbon nanotubes and spin coating of silica nanocolloids on mica, respectively. These references do not directly support the specific claims made for nanoparticle-based IR detector fabrication.

The authors should systematically check every in-text citation and ensure that each reference directly supports the associated statement. This is especially important for performance benchmarks, detector architectures, fabrication methods, and claims of state-of-the-art progress.

3. Review methodology should be clarified

Since the manuscript is presented as a comprehensive review, the literature-selection strategy should be described more clearly. The authors should state which databases were searched, the approximate time range covered, the keywords used, and the criteria for including or excluding studies. In addition, the manuscript should explain how “state-of-the-art” results were selected for the comparison tables. Without this information, the review appears selective rather than systematic.

4. Performance metrics require normalization and critical discussion

The manuscript compares detectivity, responsivity, response time, operating temperature, and spectral range across very different detector types, including photoconductors, photodiodes, phototransistors, plasmonic hot-electron devices, and hybrid heterojunctions. These metrics are strongly dependent on wavelength, bias voltage, device area, modulation frequency, noise bandwidth, temperature, and whether the noise was directly measured or estimated.

The authors should avoid direct ranking unless measurement conditions are comparable. A revised performance table should include the measurement wavelength, bias, device area, noise-evaluation method, bandwidth or modulation frequency, and temperature. Otherwise, the comparison may be misleading.

5. The exceptionally high D value for CsPbI₃/PbS requires verification

Table 5 reports a CsPbI₃/PbS bulk heterojunction with D ≈ 1.54 × 10¹⁴ Jones at room temperature. This is an extremely high value for a visible–SWIR hybrid detector and should not be presented without critical context. The authors should verify the value against the original source, specify the wavelength and measurement conditions, clarify whether the noise was measured directly or calculated from dark current, and discuss whether this value has been independently reproduced. Outlier values should be clearly identified as such rather than treated as generally representative.

6. Equations, notation, and physical definitions need correction

The manuscript should use consistent notation for (D*), (I_dark), responsivity (R), mobility, and bandgap (Eg). In several places, “D” is used where the unit “Jones” indicates that the quantity should be specific detectivity D*.

The equations should also be checked carefully. The Brus equation should be properly formatted, with all constants and effective masses clearly defined. The simplified form should be accompanied by a brief note on its limitations, including the neglect of image-charge and higher-order corrections. The expression for specific detectivity should also be revised to match the conventional definition, unless the authors explicitly justify an alternative form.

7. The manuscript needs deeper critical analysis

At present, many sections are descriptive and catalogue-like. A comprehensive review should provide stronger critical synthesis. The authors should expand the discussion of several key trade-offs, including:

1) the gain–bandwidth trade-off in photoconductors and phototransistors;

2) the relationship between trap density, ligand chemistry, and 1/f noise;

3) whether plasmonic enhancement improves detectivity or only increases responsivity;

4) why hot-electron internal quantum efficiency remains low despite strong local-field enhancement;

5) whether neuromorphic NP-based detectors currently meet practical requirements such as endurance, retention, linearity, and device-to-device reproducibility.

These additions would make the review more useful to readers seeking design principles rather than a list of reported examples.

8. Operating temperature should be treated more systematically

The manuscript repeatedly emphasizes room-temperature operation as a key advantage of NP-based IR detectors. However, it does not systematically discuss how (D*), dark current, response speed, and noise vary with temperature. A comparison with MCT and III–V detectors should be made carefully, with clear separation between SWIR, MWIR, and LWIR regimes. The authors should avoid implying that room-temperature NP detectors are broadly comparable to cooled MCT unless the comparison is made under equivalent spectral and measurement conditions.

9. The connection between fabrication methods and device performance should be strengthened

 

The title emphasizes fabrication techniques, but many parts of the manuscript focus mainly on materials and device architectures. The authors should more explicitly connect each fabrication method to concrete device-level consequences, such as film thickness, ligand removal, trap density, contact resistance, surface roughness, pixel uniformity, yield, ROIC compatibility, and scalability. This would better align the manuscript with its stated focus.

10. Toxicity, stability, and manufacturability require a more balanced discussion

Pb- and Hg-based CQDs remain central to the highest-performing NP-based IR detectors, but their toxicity, oxidation sensitivity, encapsulation requirements, and regulatory limitations should be discussed more critically. The section on lead-free alternatives is useful, but it should more clearly explain why these materials currently lag behind PbS and HgTe systems in mobility, trap density, spectral range, and detectivity.

 

Minor Comments

1. The abstract and main text should be checked for consistency in the claimed spectral coverage of NP-based IR detectors.
2. Table 1 contains a typographical error: “deed-mediated growth” should be corrected to “seed-mediated growth.”
3. Several tables contain formatting artifacts, broken words, inconsistent superscripts, and unclear entries such as “109@”. These should be corrected carefully.
4. “HE-SLS” should be defined at first use.
5. The manuscript should consistently use either “NPs” after first definition or “nanoparticles”; the terminology should not alternate unnecessarily.
6. Section 3.2 uses a bullet-point format, while surrounding sections use prose. The style should be harmonized.
7. The figure captions are too generic. Captions should explain the specific message of each figure, not merely name the figure.
8. The claim that continuous-flow synthesis achieves size dispersity below 3% should specify the measurement method and whether the dispersity is number-weighted, volume-weighted, or inferred from optical linewidth.
9. The discussion of black phosphorus stability and retained mobility after functionalization should be checked against the cited source and qualified if necessary.
10. The acknowledgments and funding/conflict-of-interest statements should be checked for completeness, especially because company support is mentioned.

 

 

The manuscript addresses an important and rapidly developing field and has the potential to become a useful reference on nanoparticle-based infrared detectors. However, the current version requires major revision. The most important issues are the scientific reliability of AI-generated figures, the accuracy of references, the normalization and critical discussion of performance metrics, and the need for deeper analysis of noise, stability, temperature dependence, and manufacturability. I recommend major revision before further consideration for publication.

Author Response

Dear Reviewer,

thank you very much for your detailed and insightful comments. They have helped us tremendiously to carefully revise our manuscript. All changes in the manuscript are higlighted in yellow. Please find attached a list of point-by-point responses to your comments.

Kind regards,

AXEL KLEIN

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

REVIEW

on the manuscript “Advances in Nanoparticle-Based Fabrication Techniques for Infrared Detectors: A Comprehensive Review”

by Mahboubeh Dolatyari, Ali Rostami and Axel Klein

 

In the presented manuscript the review of near-infrared detection systems based on nanoparticles is carried out. Brief tutorial-like introduction into the basic materials systems, synthesis techniques, properties and figures of merit of the discussed photodetectors is given. Some performance characteristics of nanoparticle-based photodetectors are considered in terms of their potential applications. The results of experimental investigations of selected photodetectors based on various materials are presented. Critical challenges and perspectives are outlined.

Overall, the paper is organized well and at high scientific level.

The manuscript falls under the scope of the Inorganics journal. The presented results make the paper suitable for publication in the journal.

However, in the reviewer’s opinion, the manuscript should be improved before publication. The details are listed below.

1. Principles of operation of this type of device should be described in more details in Introduction.
2. Authors should also pay more attention to such characteristic as selectivity. How is it achieved in nanoparticle-based infrared photodetectors?
3. Figure 1, Right panel: two very similar boxes with lower cost and room temperature operation should be commented.
4. Page 3: all the denominations in the equations should be described, for example, q, kB, h, epsilon and others. All the equations later in the text should also be checked.
5. Figure 2: Sandwich structure and vertical arrows in Central panel should be commented.
6. Section 2, Key NP materials for IR detection: Si-compatible nanostructured photodetectors, including heterostructures with self-organized quantum dots of Ge on Si, GeSiSn photodiodes based on quantum dots are missing.
7. Page 5: one of the key synthesis strategies – epitaxial formation of nanostructures by different growth modes – should be mentioned in the Table 1 and discussed in the text.
8. Figure 3, Figure 4, Figure 5, Figure 6, Figure 7, Figure 8: The quality of figures is rather low. The intention of some arrows is not clear. Text is not readable. All the texts in the figures should be checked and corrected.
9. Section 3.3: Silicon-based avalanche photodiodes, photomultipliers (including single photon avalanche diode detectors) should be mentioned as one of the device architectures.
10. Page 14: k or kB should be used consistently throughout the text for Boltzmann constant.

 

Conclusion: The presented manuscript may be published in the Inorganics journal after major revision.

Author Response

Dear Reviewer,

thank you very much for your detailed and insightful comments. They have helped us tremendiously to carefully revise our manuscript. All changes in the manuscript are higlighted in yellow. Please find attached a list of point-by-point responses to your comments.

Kind regards,

AXEL KLEIN

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The author has carefully addressed the comments and suggestions raised in the previous round of review. The manuscript has been significantly improved in terms of technical clarity, experimental description, data analysis, and overall presentation. The revisions adequately resolve the concerns regarding the methodology, discussion of results, and organization of the manuscript. Overall, the revised manuscript meets the requirements for publication. Therefore, I recommend that the manuscript be accepted for publication.

Reviewer 3 Report

Comments and Suggestions for Authors

REVIEW

on the manuscript “Advances in Nanoparticle-Based Fabrication Techniques for Infrared Detectors: A Comprehensive Review”

by Mahboubeh Dolatyari, Ali Rostami and Axel Klein

 

In the presented manuscript the review of near-infrared detection systems based on nanoparticles is carried out. Brief tutorial-like introduction into the basic materials systems, synthesis techniques, properties and figures of merit of the discussed photodetectors is given. Some performance characteristics of nanoparticle-based photodetectors are considered in terms of their potential applications. The results of experimental investigations of selected photodetectors based on various materials are presented. Critical challenges and perspectives are outlined.

Overall, the paper is organized well and at high scientific level.

The manuscript falls under the scope of the Inorganics journal. The presented results make the paper suitable for publication in the journal.

The revision of the manuscript is satisfactory. Authors have answered all the questions and made necessary amendments.

Conclusion: The presented manuscript may be published in the Inorganics journal in present form.