Interface-Engineered Highly Responsive ReS₂ Photodetector

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The work is interesting and describes a method for significantly improving a thin-layer ReS2 photodetector.

I have a few remarks:
General remarks
G.1 I would appreciate the inclusion of a discussion on the potential applications of the described sensor.
G.2 There is no information on how many devices were fabricated and tested.
G.3 What about long-term stability? How much time passed between fabrication and testing? Was any degradation of the sensor observed over time?
G.4 The abstract mentions broadband spectral detection, but no spectral response is presented. Only a single wavelength was used during the reported measurements.

Specific remarks:
S.1 Line 22: I would question whether the term “rapid response rise time of 0.15 s” is appropriate, considering the typical rise times observed in entire family of sensors (including the classical ones).
S.2 Line 182 (Figure 2): Plot (a) is described as being under “dark conditions” with a wavelength indicated in the figure, whereas plot (c) is described as “under 637 nm laser illumination” but is labeled as “dark” in the figure. This inconsistency should be clarified.
S.3 Isn't there a contradiction 
Abstract (lines 20–22):
“…achieved a responsivity of 0.88 A W⁻¹ with a rapid response rise time of 0.15 s, a significant improvement from the intrinsic values of 12 mA W⁻¹ responsivity and 8 s rise time.”
vs.:
Results section (lines 216–218):
“…the photoresponse rise time (τr) and fall time (τf) were determined to be 0.15 s and 7.9 s for the intrinsic substrate, while the etched substrate exhibited values of 8 s and 9 s, respectively.”

Author Response

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Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript presented by Wang et al present interesting results. However, the reviewer has the following comments:

1. The reviewer recomends rephrase the abstract. Iy is dificult to understand the objective of the manuscript.
2.  The materials and methods section is incomplete. Several parameters and properties are missing.  
3.  The reviewer strongly suggest to improve figure 2. Adding the I-V curves in semilog scale can improve the analysis of the results. 
4. Figure 3 must be improved. The results presented in this figure are ambiguous in its present form. It is not clearly exhibited the delay and decay characteristics. 
5. There is a lack of analysis and discussion of the results. With the measurements performed there are other parameters that can be calculated. For example, the photosensitivity of the device and the detectivity.
6.  The reviewer does not understand the purpose of the equations 2, 3 and 4. Since there is no calculation of parameters from these equations. The equations must be used to extract parameters and compare them with literature.  

Author Response

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Reviewer 3 Report

Comments and Suggestions for Authors

In this work, Wang et al. fabricated ReS₂/n-Si heterojunction photodiode with responsivity. This work is important in heterojunction photo-detecting materials of responsivity. I recommend the manuscript to publish after the following comments are addressed:

• For photodiode needs high responsivity based on Schottky behavior characteristics but authors fabricated photodiode shows nearly ohmic behavior in Fig. 2, could you explain it?
• In according to previous work [Opt. Exp. 2011, 29, 3567–3574], the response time of ReS₂ photodiode is 83.5/325.3 ms faster than this manuscript (0.15/7.9 s), the authors should physical mechanism about response time of photodiode and explain it.
• Author should show I_on/I_off
• Calculate the detectivity of photodiode.

Author Response

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Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Thank you for all your explanations.

Minor remarks:

* Line 154 (Fig. 1b): The resolution of this figure is too low for the image size. Without zooming, reading this plot is impossible, and the resolution is too low when the image is zoomed.

* Line 257 (Fig. 3): Please take a look at the power units. Sometimes you write "uw" or "uW", but I guess it should be "micro-W".

Comments

* In Fig. 1c, you present the devices, right? Is the active area the same for both? Since the area factor may also influence the parameters.

* When asked about the number of samples, you wrote that only a single device was prepared. OK, this is still fine when you want to show the capabilities of the technology. However, you are making a comparison between just two devices. I bet that during the manufacturing process, more than a single device could have been -or was- manufactured. Are you comparing the only working devices, or maybe the best from the modified series with the best/average/worst from the reference (non-plasma-treated) series? You may consider including this kind of discussion in your paper

In any case, I still believe the paper is publishable, as it demonstrates the effect of a technological modification.

Author Response

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Reviewer 2 Report

Comments and Suggestions for Authors

The authors address the reviewer comments

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Reviewer 3 Report

Comments and Suggestions for Authors

Accept in present form

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