Bow-Tie Microwave Diodes on the Base of Modulation-Doped Semiconductor Structure with Wide Spacer: Theory and Experiment

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript demonstrated the electrical properties of bow-tie diodes based on modulation-doped semiconductor structures with a wide spacer. The results are impressive and most of the descriptions are reasonable. However, there are some lacking in the technical explanations throughout the manuscript, which mislead to understand the research work. A revision is required to further stress it, there are some suggestions for the authors to consider:

The fabrication of the devices, methods and apparatuses, should bedescribed clearly.

The presentation of figures should be improved.

Why the IV response is strongly influenced by electron capture into deep levels?

What is the differences among this work and those reported in refs. [46,47]?

Bow-tie microwave diodes have proven to be effective sensors, however, the characteristics relate to sensing have not been investigated in this work.

Author Response

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Reviewer 2 Report

Comments and Suggestions for Authors

Review of the article «Bow-tie Microwave Diodes on the Base of Modulation-doped Semiconductor Structure with Wide Spacer: Theory and Experiment» by the authors Algirdas Sužiedėlis, Steponas Ašmontas, Jonas Gradauskas, Aurimas Čerškus, Andžej Lučun, Maksimas Anbinderis

 

The work has a practical focus and contains detailed studies of bow-tie diodes fabricated from modulation-doped semiconductor structures with wide spacers enable a comprehensive generalization of their detection properties, considering the diode geometry and contact design, orientation relative to the crystallographic axes, dimensions of the active region, and illumination conditions.

 

There are some comments on the materials in the manuscript, but they do not reduce its value.

 

1. The abstract requires more specifics. It should concisely yet clearly describe the obtained results and their relevance. For instance: "The voltage sensitivity results for the investigated bow-tie diodes indicate that, for most diodes, the detected voltage originates from electron heating by the microwave electric field, as evidenced by the polarity of the detected voltage matching the thermoelectric emf of hot carriers." The current abstract, in contrast, relies on general statements.

 

2. The authors claim that [48] describes the manufacturing process of a bow-tie type planar diode [48], but it does not contain detailed manufacturing technology for these elements.планарного диода типа «галстук-бабочка» подробно описан в [48].

Exactly, Lines 161: The article [48 - Sužiedėlis, A.; et al. ...] investigates bow-tie diodes with broken geometric symmetry, fabricated on InAlAs/InGaAs heterostructures with selective doping and without InAs inserts. Furthermore, here examines the characteristics of the microwave-induced voltage under additional visible light illumination, using it as an analytical tool.

 

3. It would be desirable to indicate the measurement errors on the figures.

 

4. Line 165: It would be advisable to specify the spectrum of the photo-lamp to allow for an assessment of the influence of its spectral composition on the diode's operation.

 

 

5. Line 474: This sentence is meaningless, as are the sentences in lines 475-477. The content of lines 475-477 pertains to the research objectives, which should be formulated at the beginning of the research section of the manuscript.

 

6. The Discussion section should address why the experimental dependence of the bow-tie diode I-V asymmetry on the diode neck width (Figure 10) deviates significantly from the calculated one. The experimental nonlinearity appears to be greater than predicted. It would also be valuable to compare the contributions of the neck width to the I-V asymmetry in both calculated and experimental cases for the different diode designs (WLAD, BLAD, WLSP, BLSD).
7. For the graphs, it is better to use a consistent line thickness for plotting the data. In this case, the optimal line thickness is shown in Figure 10.

Author Response

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Reviewer 3 Report

Comments and Suggestions for Authors

 Title: Bow-tie Microwave Diodes on the Base of Modulation-doped Semiconductor Structure with Wide Spacer: Theory and Experiment

Keywords: „spacer” it is not a keyword, very general

„bow-tie microwave diode” already in title, not useful

„metallic contacts” very general, not a keywords.

Line 132: “Figure 1. Cross-section of modulation-doped semiconductor structure with energy band diagram...” Why the distance is vertical? Normally, the electrical circuit must be horizontal, and magnitude of electron energy could be read on vertical, as the density.

Line 151: „Micrographs of the diodes with d = 3 μm are shown in Figure 3.” Very interesting, but some details about micrographs technique will be useful. The sample are prepared somehow? The planar diodes are visible?

Line 153: „Figure 3. Micrographs of the bow-tie diodes:...” Figure 2 is a illustration for Figure 3. So, the diodes must be in the same position, and some arrow (explanations) must be add in Figure 2 and even in Figure 3.

Line 180: „...Figure A1, while maps for BLPF and BLSF diodes are presented in Figure A2” No, maybe Maps of the voltage sensitivity for WLPF and WLSF diodes are shown in Figure 4 a,b  while maps for BLPF and BLSF diodes are presented in Figure 4 c, d. 

Line 227: „ .... depending on illumination conditions and neck width, WL SD diodes can be 10 to 40 times more sensitive to microwave radiation than the corresponding BL diodes.” What about illumination conditions? Some values? Units of measurements?

Line 233: „ ...sensitivity can be expressed as [1]:” No, typo: „ sensitivity can be expressed as (1)”. [1] is a citation.

Line 233 – 240: Explanations are OK, but units of measurement will be useful.

Line 239: ”N is a factor that depends on the microwave frequency 𝜔, electron momentum relaxation time 𝜏𝑖 ...” . OK, first small problem is about „frequency 𝜔”, because frequency is included in „𝜔”, (pulsation). The main problem is for equation (2), no citations are available. Equation 2 is not very usual, a citation is necessary.

Line 282: „As shown in Figure A3, the I-V characteristics presented in Figure 7 are indeed non linear and asymmetric with respect to the applied voltage...” I sincerely don’t understand where non linear is. Linearity is obvious.

Line 320: „𝑅(0)𝑡ℎ𝑒𝑜𝑟”  Theoreticat is OK, but 𝑅(0) ?

 

 

Line 322: Typo: Sheet resistance 𝑹𝒔𝒉, Ω/□

In Table 1: What is illuminated or Dark? Units of measurement? Also in Figure 6.

Table 1, “Contact resistivity 𝝆𝒄, Ω·mm: 0.41 ± 0.53 and 0.45 ± 0.47” Very difficult to accept these values, also other values must be explained. Resistivity could be negative? And the precision and the uncertainty of the measurements must be discussed.

Line 353: “…theoretical values calculated from the phenomenological expression [1]:” Maybe “ … the phenomenological expression (1)” And in other places in your paper.

Line 615: “White-light illumination” Very vague, white-light is not something described with precision. Maybe spectral composition, correlated color temperature.

 

Author Response

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Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

It is acceptable for publication.