Physical Vapor Deposition of Indium-Doped GeTe: Analyzing the Evaporation Process and Kinetics
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe topic seems interesting, considering the potential use of evaporated particles to produce layers for optoelectronics.
The quality of the manuscript appears to be quite good, also considering the quality of the tables and figures.
My comments are as follows:
1. However, the article would be more interesting with the addition of an experimental set-up with a clear drawing of the experimental set-up.
2. Authors should cite several recent literature items (2023-2024).
Author Response
The topic seems interesting, considering the potential use of evaporated particles to produce layers for optoelectronics. The quality of the manuscript appears to be quite good, also considering the quality of the tables and figures.
Comment 1: However, the article would be more interesting with the addition of an experimental set-up with a clear drawing of the experimental set-up.
Response 1: Agree. We have added a clear drawing of the experimental set-up (Figure 1) in the revised manuscript to enhance the understanding of our experimental process.
Comment 2: Authors should cite several recent literature items (2023-2024).
Response 2: Agree. We have included several recent literature items (2023-2024) in the revised manuscript to ensure our references are up-to-date and comprehensive.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors presented an in-depth analysis of the evaporation kinetics of indium-doped chalcogenides, GeTe4 and GeTe5, by using physical vapor deposition technique. This study indicated that the evaporation rates of GeTe4 and GeTe5 significantly increase exponentially with the introduction of indium, especially at higher temperatures. The results show that the addition of indium affects the evaporation rate and increases the energy requirement of the evaporation process, providing new insights into the thermal dynamics of these materials. This work presents a good research structure and results. However, all formulas need to be modified to express their meaning more clearly, such as Equations (6) and (7). After carefully reading and evaluating the manuscript, I recommend that the article requires revision before publication.
Author Response
Comments: The authors presented an in-depth analysis of the evaporation kinetics of indium-doped chalcogenides, GeTe4 and GeTe5, by using physical vapor deposition technique. This study indicated that the evaporation rates of GeTe4 and GeTe5 significantly increase exponentially with the introduction of indium, especially at higher temperatures. The results show that the addition of indium affects the evaporation rate and increases the energy requirement of the evaporation process, providing new insights into the thermal dynamics of these materials. This work presents a good research structure and results. However, all formulas need to be modified to express their meaning more clearly, such as Equations (6) and (7). After carefully reading and evaluating the manuscript, I recommend that the article requires revision before publication.
Response: Dear Reviewer, Thank you for your thorough evaluation and constructive feedback on our manuscript. We appreciate your positive remarks about our research structure and results.
We thank you for pointing this out. We have revised section 2.3 including the formulas to ensure they clearly express their meaning and improve readability.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe paper "Physical Vapor Deposition of Indium-Doped GeTe: Analyzing the Evaporation Process and Kinetics" reports on deposition and experimental thermal properties of the In-doped GeTe4 and GeTe5 films and bulk samples. The authors use the well-known method of deposition of films, hence the presented results should be reliable. The title of the article reflects its content. The abstract is concise and presents the main theses of the work.
However, some questions arise about the manuscript.
1. In the section “2.2. Thin Film Preparation”: What temperature of the glass substrate?
2. In the section “2.2. Thin Film Preparation”, lines 124-126: “The thickness of the films, which ranged from 300 nm - 650 nm, was determined based on the evaporation time and estimated using the Swanepoel method [25].” But it’s different methods. The “Swanepoel method” needs optical measurement. If such measurement was done, they do need their added to the text.
3. In the section “3.1. Thermal Properties of Bulk Sample”: Report about glass transition temperature, onset temperature of crystallization, peak temperature of crystallization, and peak melting temperature. What crystal structure is for such materials? Need added XRD for these materials.
4. In the section “3.1. Thermal Properties of Bulk Sample”: What method was used to establish the composition ratio?
5. In the section “3.2. Evaporation Rate of Chalcogenide Ge-Te-In Glasses”: Are these amorphous or polycrystalline samples?
6. In the section “3.2. Evaporation Rate of Chalcogenide Ge-Te-In Glasses”: As is known, the thermal method of deposition is non-equilibrium. Therefore, in this case, additional studies are necessary: studies of the component composition, XRD, and electron microscopy.
In summary – Additional experimental studies are needed. Especially, this applies to films.
I recommend this article for publication in the “Inorganics” after a major revision.
Author Response
The paper "Physical Vapor Deposition of Indium-Doped GeTe: Analyzing the Evaporation Process and Kinetics" reports on deposition and experimental thermal properties of the In-doped GeTe4 and GeTe5 films and bulk samples. The authors use the well-known method of deposition of films, hence the presented results should be reliable. The title of the article reflects its content. The abstract is concise and presents the main theses of the work.
- Comment 1: In the section 2.2. Thin Film Preparation”: What temperature of the glass substrate?
Response 1: In the section "2.2. Thin Film Preparation," we have clarified that the glass substrate was maintained at ambient temperature (300K) during the deposition process. This information has been added to the revised manuscript to provide a complete description of the experimental conditions.
- Comment 2: In the section “2.2. Thin Film Preparation”, lines 124-126: “The thickness of the films, which ranged from 300 nm - 650 nm, was determined based on the evaporation time and estimated using the Swanepoel method [25].” But it’s different methods. The “Swanepoel method” needs optical measurement. If such measurement was done, they do need their added to the text.
Response 2: We acknowledge the confusion regarding the thickness determination method. The thickness of the films, ranging from 300 nm to 650 nm, was indeed measured using optical methods as per the Swanepoel method. We have now clarified this in the revised manuscript, specifying that optical measurements were conducted, and have included the relevant details of these measurements (section 3.4).
- Comment 3: In the section “3.1. Thermal Properties of Bulk Sample”: Report about glass transition temperature, onset temperature of crystallization, peak temperature of crystallization, and peak melting temperature. What crystal structure is for such materials? Need added XRD for these materials.
Response 3: We have now included X-ray Diffraction (XRD) analysis to determine the structure of the materials (section 3.1). The bulk samples obtained from our experiments are amorphous. These materials belong to the group of Chalcogenide phase-change materials (PCMs), known for their unique behavior in switching between amorphous and crystalline states, as discussed in the introduction. When crystallized, they possess a tetrahedral structure. This additional information, along with the XRD data, has been added to the revised manuscript.
- Comment 4: In the section “3.1. Thermal Properties of Bulk Sample”: What method was used to establish the composition ratio?
Response 4: As explained in the section "2.1. Bulk Sample Preparation," the composition ratio was initially established using the stoichiometric method during the preparation of the bulk sample. To maintain the composition ratio, evacuated quartz ampoules were used. We did not measure the composition ratio after the bulk sample was prepared.
- Comment 5: In the section “3.2. Evaporation Rate of Chalcogenide Ge-Te-In Glasses”: Are these amorphous or polycrystalline samples?
Response 5: Dear Reviewer, the bulk samples are amorphous, but in the thin films obtained by the PVD method with an increase the indium content to 20%, the appearance of a polycrystalline structure is observed. We have clarified the structural state of the prepared thin film in section 3.4. Based on our analysis, the thin films are polycrystalline, as indicated by SEM data. This information, along with the corresponding SEM data, has been added to the revised manuscript.
- Comment 6: In the section “3.2. Evaporation Rate of Chalcogenide Ge-Te-In Glasses”: As is known, the thermal method of deposition is non-equilibrium. Therefore, in this case, additional studies are necessary: studies of the component composition, XRD, and electron microscopy.
Response 6: Recognizing the non-equilibrium nature of the thermal deposition method, we have conducted additional studies. The results from these studies have been incorporated into the revised manuscript (section 3.4.) to provide a more comprehensive analysis of the deposited films, ensuring a thorough understanding of their structural and compositional characteristics.
We believe these revisions have significantly improved the clarity and quality of our manuscript. Thank you for your valuable suggestions.
Round 2
Reviewer 3 Report
Comments and Suggestions for AuthorsThe main recommendations are taken into account. I recommend the publication of this article in Inorganics.
