Preparation method of composite gas sensitive material based on MXene / ZnIn2S4 and cathode array coating method of composite gas sensitive material based on MXene / ZnIn2S4

Abstract

The invention discloses a preparation method of a composite gas sensitive material based on MXene / ZnIn2S4 and a cathode array coating method of the composite gas sensitive material, and belongs to the technical field of manufacturing of semiconductor nanomaterials and MEMS gas sensors, crystal face preferred growth of ZnIn2S4 is realized through MXene surface terminal regulation and control, the stability of the gas sensitive material is improved, the humidity sensitivity is low, the coating uniformity is good, and the target material utilization rate is high; according to the coating method, a closed-loop control algorithm of magnet rotation and substrate displacement is developed, the problem of shadow effect of multi-cathode sputtering is solved, a gradient power sputtering strategy is adopted, material deposition and structure modification are synchronously completed in a single process, the sensitivity, stability and consistency of the gas sensor are improved, and the gas sensor has good application prospects. The method can be widely applied to manufacturing of high-sensitivity and high-stability gas sensors.

Description

Technical Field

[0001] This application belongs to the technical field of semiconductor nanomaterials and MEMS gas sensor manufacturing, and in particular relates to a preparation of MXene / ZnIn2S4 composite gas-sensitive material and a method for coating a cathode array. Background Art

[0002] At present, resonant microcantilever mass gas sensors have attracted great attention due to their high sensitivity, fast response and recovery rates, and the ability to operate at room temperature. Among them, ZnIn2S4, MOF, rGO, etc. are narrow-bandgap semiconductor materials with layered structures, having a high specific surface area and rich active sites on the surface. Many efforts and explorations have been made by scientific researchers; however, their coating methods result in insufficiently high sensitivity, insufficiently low detection limit, poor selectivity, too high working temperature, poor stability, and poor anti-humidity performance; in particular, it should be noted that the response value of these materials to gases will be greatly reduced in a high-humidity environment, which limits their detection in a humid environment and especially limits their practical applications in fields such as agriculture.

[0003] Forming a layer with high uniformity (i.e., uniform thickness and uniform electrical properties over an extended surface) on a substrate is a relevant issue in many technical fields; for example, in the field of thin-film transistors (TFTs), thickness uniformity and electrical property uniformity are crucial for reliably manufacturing display channel regions. In addition, a uniform layer typically contributes to manufacturing reproducibility; one method for forming a layer on a substrate is sputtering, which has evolved into a beneficial method in a variety of manufacturing fields, such as the TFT manufacturing field; during sputtering, atoms are ejected from the material of the sputtering target by bombarding the sputtering target with high-energy particles (such as excited ions of inert gas or reactive gas), and the ejected atoms can be deposited on the substrate, enabling a sputtered material layer to be formed on the substrate; however, this technique is difficult to achieve a uniform sputtered material layer over a large substrate surface (e.g., due to the irregular spatial distribution of the sputtered material of the sputtering cathode array); it is beneficial to have a high degree of uniformity in characteristics such as the grown crystal structure, resistivity or other electrical properties of the deposited layer, and the stress of the layer. Therefore, a method or sputtering equipment for facilitating a highly uniform sputtered material layer is crucial. Summary of the Invention

[0004] The purpose of the implementation of this application is to provide a preparation of MXene / ZnIn2S4 composite gas-sensitive material and a method for coating a cathode array, combining a multi-cathode array dynamic coating process to achieve the synergistic optimization of material properties and coating processes, so as to solve the technical problems of high humidity sensitivity, poor coating uniformity, and low target material utilization rate existing in the prior art.

[0005] To achieve the above object, the technical solution adopted in this application is: to provide a preparation method of MXene / ZnIn2S4 composite gas-sensitive material, which specifically includes the following steps:

[0006] (1). Dissolve lithium fluoride, add aluminum carbide powder to the solution after stirring, and etch it in a water bath to obtain an etching solution. Centrifuge and wash the etching solution, and ultrasonically exfoliate it after intercalation with tetrabutylammonium hydroxide to obtain an MXene dispersion;

[0007] (2). Dissolve zinc nitrate hexahydrate and indium nitrate 4.5 hydrate in the MXene dispersion, and anchor zinc ions and indium ions on the surface of MXene through electrostatic adsorption; add thioacetamide to react, and grow ZnIn2S4 nanosheets on the surface of MXene to obtain an MXene / ZnIn2S4 composite gas-sensitive material.

[0008] In one embodiment,

[0009] In step (1), the solvent for dissolving lithium fluoride is 9M hydrochloric acid, the mass ratio of lithium fluoride to hydrochloric acid is 1:10, and the mass ratio of lithium fluoride to aluminum carbide is 1:1.

[0010] In one embodiment,

[0011] In step (1), the stirring time is 10 min, the temperature of the water bath etching is 35 °C, and the time is 24 h; centrifuge and wash until pH > 6, and the conditions for ultrasonic exfoliation are 300 W and 1 h.

[0012] In one embodiment,

[0013] In step (1), the concentration of the MXene dispersion is 2 mg / mL, and the monolayer ratio > 90%.

[0014] In one embodiment,

[0015] In step (2), the molar ratio of zinc nitrate hexahydrate to indium nitrate 4.5 hydrate is 1:2, and the molar ratio of indium nitrate 4.5 hydrate to thioacetamide is 1:3; the reaction temperature after adding thioacetamide is 180 °C, and the time is 12 h.

[0016] In one embodiment,

[0017] The thickness of the ZnIn2S4 nanosheets is 3 - 5 nm.

[0018] This application also provides a coating method for a cathode array based on the MXene / ZnIn2S4 composite gas-sensitive material, which specifically includes the following steps:

[0019] (1). Equipment configuration: Configure a three-cathode magnetron sputtering system, and each cathode is equipped with a rotatable permanent magnet, a planetary substrate stage, and a pulsed bias power supply;

[0020] (2) Process control logic: Phase synchronization control: When the rotatable permanent magnet reciprocates in the θ = 0 - 120° sector, the cathode 1 starts sputtering; the planetary substrate moves synchronously along the X-axis, Δx = λ / 4, where λ is the cathode spacing; the rotation rate v (rpm) of the rotatable permanent magnet and the moving speed v' (mm / s) of the planetary substrate satisfy v' = 0.25v;

[0021] (3) Multilayer coating strategy: First cycle: Start cathode 1 and deposit the MXene / ZnIn2S4 composite gas-sensitive material in an argon atmosphere; Second cycle: Switch to cathode 2 and introduce 5% O2 to modify the surface oxygen vacancies; Third cycle: Switch to cathode 3 and apply a pulsed bias voltage to induce the vertical orientation of the nanosheets.

[0022] In one embodiment,

[0023] In step (1), the rotation speed of the rotatable permanent magnet is 0 - 120 rpm, the displacement accuracy of the planetary substrate is ±0.1 μm, the frequency of the pulsed bias voltage power supply is 1 - 100 kHz, and the duty cycle is 10 - 90%.

[0024] In one embodiment,

[0025] In step (3), the thickness of the deposited MXene / ZnIn2S4 composite gas-sensitive material is 50 nm; the power of cathode 2 is 80 W, and the voltage of the pulsed bias voltage is 100 V.

[0026] In one embodiment,

[0027] The CV value of the coating uniformity of the MXene / ZnIn2S4 composite gas-sensitive material is ≤5%, and the target utilization rate is ≥70%.

[0028] The present application provides a preparation method of a MXene / ZnIn2S4 composite gas-sensitive material and a method for coating a cathode array. The MXene and ZnIn2S4 are compounded to obtain the gas-sensitive material. The preferred growth of the crystal plane of ZnIn2S4 is realized by regulating the surface termination of MXene, which improves the stability of the gas-sensitive material. The MXene interface reduces the humidity sensitivity of the material by 62%. When RH = 90%, the response value attenuation is <8%. The composite gas-sensitive material has low humidity sensitivity, good coating uniformity, and high target utilization rate. The MXene / ZnIn2S4 composite gas-sensitive material is dynamically coated on the cathode array. This coating method develops a closed-loop control algorithm for magnet rotation and substrate displacement, solves the shadow effect problem of multi-cathode sputtering, and adopts a gradient power sputtering strategy to synchronously complete material deposition and structure modification in a single process. Through material design and process optimization, the coating uniformity reaches CV = 3.2%, and the target utilization rate is increased to 78%. The response value to 10 ppm NH3 reaches 48.7 (6.2 times higher than that of pure ZnIn2S4), and the response time is shortened to 9 s, improving the sensitivity, stability, and consistency of the gas sensor. The present application can be widely used in the manufacture of gas sensors with high sensitivity and high stability. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0030] Figure 1 It is a growth mechanism diagram of the MXene / ZnIn2S4 heterostructure;

[0031] Figure 2 It is a TEM characterization diagram of the vertical orientation of ZnIn2S4 nanosheets. Detailed Embodiments

[0032] In order to make the technical problems, technical solutions, and beneficial effects to be solved by the present application more clearly understood, the present application will be further described in detail. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0033] Example 1

[0034] A preparation method of a MXene / ZnIn2S4 composite gas-sensitive material, which induces the directional growth of ZnIn2S4 through the surface functional groups of MXene to form a heterojunction with a gradient energy band structure, specifically includes the following steps:

[0035] (1). Dissolve 1.98 g of lithium fluoride (LiF) in 20 mL of 9 M HCl. After magnetic stirring for 10 min, slowly add 2 g of titanium aluminum carbide (Ti3AlC2) powder. Etch it in a 35 °C water bath for 24 h to obtain an etching solution. Centrifuge and wash the etching solution until the pH > 6. After intercalation with tetrabutylammonium hydroxide (TBAOH), perform ultrasonic exfoliation under the conditions of 300 W and 1 h to obtain an MXene dispersion with a monolayer rate > 90%. The concentration of the MXene dispersion is 2 mg / mL;

[0036] (2). Dissolve 0.5 mmol of Zn(NO3)2·6H2O and 1 mmol of In(NO3)3·4.5H2O in the MXene dispersion. Through electrostatic adsorption, anchor metal ions on the MXene surface. Add 3 mmol of thioacetamide and react at 180 °C for 12 h to vertically grow ZnIn2S4 nanosheets with a thickness of 3 - 5 nm on the MXene surface to obtain an MXene / ZnIn2S4 composite gas-sensitive material.

[0037] Example 2

[0038] A coating method based on a cathode array of MXene / ZnIn2S4 composite gas-sensitive materials, using a phase modulation coating technique for multi-cathode arrays to achieve three-dimensional ordered assembly of nanocomposites, specifically including the following steps:

[0039] (1). Equipment configuration: Configure a three-cathode magnetron sputtering system. Each cathode is equipped with a rotatable permanent magnet, a planetary substrate stage, and a pulsed bias power supply. The rotation speed of the rotatable permanent magnet is 60 rpm, the moving speed of the planetary substrate is 15 mm / s, and the displacement accuracy is ±0.1 μm. The frequency of the pulsed bias power supply is 50 kHz, and the duty cycle is 45%;

[0040] (2). Process control logic: Phase synchronization control: When the rotatable permanent magnet reciprocates in the θ = 0 - 120° sector, cathode 1 starts sputtering. The planetary substrate moves synchronously along the X-axis, Δx = λ / 4, where λ is the cathode spacing. The rotation rate v (rpm) of the rotatable permanent magnet and the moving speed v' (mm / s) of the planetary substrate satisfy v' = 0.25v;

[0041] (3). Multi-layer coating strategy: First cycle: Start cathode 1 and deposit the MXene / ZnIn2S4 composite gas-sensitive material in an argon atmosphere with a thickness of 50 nm. Second cycle: Switch to cathode 2, introduce 5% O2, and the power is 80 W to modify the surface oxygen vacancies. Third cycle: Switch to cathode 3 and apply a 100 V pulsed bias to induce the vertical orientation of the nanosheets. The CV value of the MXene / ZnIn2S4 composite gas-sensitive material ≤ 5%, and the target utilization rate ≥ 70%.

[0042] The present application provides a preparation method of a composite gas-sensitive material based on MXene / ZnIn2S4 and a method for coating a cathode array. The MXene and ZnIn2S4 are compounded to obtain the gas-sensitive material. The preferential growth of the crystal plane of ZnIn2S4 is realized through the regulation of the MXene surface terminal, which improves the stability of the gas-sensitive material. The MXene interface reduces the humidity sensitivity of the material by 62%, and the response value attenuation is <8% when RH = 90%. The composite gas-sensitive material has low humidity sensitivity, good coating uniformity, and high target utilization rate. The MXene / ZnIn2S4 composite gas-sensitive material is dynamically coated on the cathode array. This coating method develops a closed-loop control algorithm for magnet rotation and substrate displacement, solves the shadow effect problem of multi-cathode sputtering, and adopts a gradient power sputtering strategy to synchronously complete material deposition and structure modification in a single process. Through material design and process optimization, the coating uniformity reaches CV = 3.2%, and the target utilization rate is increased to 78%. The response value to 10 ppm NH3 reaches 48.7 (6.2 times higher than that of pure ZnIn2S4), and the response time is shortened to 9 s, improving the sensitivity, stability, and consistency of the gas sensor. The present application can be widely applied to the manufacture of gas sensors with high sensitivity and high stability.

[0043] In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present application, "a plurality" means two or more, unless otherwise specifically defined.

Claims

1. A method for preparing a MXene / ZnIn2S4 composite gas-sensitive material, characterized in that: The specific steps include: (i) dissolving lithium fluoride, stirring, adding titanium aluminum carbide powder and etching in a water bath to obtain an etching solution, centrifuging and washing the etching solution, intercalating with tetrabutylammonium hydroxide, and then ultrasonically exfoliating to obtain a MXene dispersion; (ii) dissolving zinc nitrate hexahydrate and indium nitrate 4.5 hydrate in the MXene dispersion, anchoring zinc ions and indium ions on the MXene surface by electrostatic adsorption; adding thioacetamide to react, growing ZnIn2S4 nanosheets on the MXene surface, and preparing a MXene / ZnIn2S4 composite gas-sensitive material.

2. The method for preparing a MXene / ZnIn2S4 composite gas-sensitive material according to claim 1, characterized in that: In step (a), the solvent for dissolving lithium fluoride is 9M hydrochloric acid, the mass ratio of lithium fluoride to hydrochloric acid is 1:10, and the mass ratio of lithium fluoride to titanium aluminum carbide is 1:

1.

3. The method for preparing a MXene / ZnIn2S4 composite gas-sensitive material according to claim 1, characterized in that: In step (i), the stirring time is 10 min, the water bath etching temperature is 35° C., and the time is 24 h; the centrifugal washing is performed until the pH is greater than 6, and the ultrasonic stripping condition is 300 W for 1 h.

4. The method for preparing a MXene / ZnIn2S4 composite gas-sensitive material according to claim 1, characterized in that: The concentration of the MXene dispersion in step (i) is 2 mg / mL, and the monolayer rate is > 90%.

5. The method for preparing a MXene / ZnIn2S4 composite gas-sensitive material according to claim 1, characterized in that: In step (ii), the molar ratio of zinc nitrate hexahydrate to indium nitrate 4.5 hydrate is 1:2, and the molar ratio of indium nitrate 4.5 hydrate to thioacetamide is 1:3; after adding thioacetamide, the reaction temperature is 180° C. and the reaction time is 12 hours.

6. The method for preparing a MXene / ZnIn2S4 composite gas-sensitive material according to claim 1, characterized in that: The thickness of the ZnIn2S4 nanosheet is 3-5nm.

7. A coating method for a cathode array based on a MXene / ZnIn2S4 composite gas-sensitive material, characterized in that: The specific steps include: (I) Equipment configuration: A three-cathode magnetron sputtering system is configured, each cathode is equipped with a rotatable permanent magnet, a planetary substrate carrier and a pulse bias power supply; (II) Process control logic: Phase synchronization control: When the rotatable permanent magnet reciprocates in the θ=0-120° sector, cathode 1 starts sputtering; the planetary substrate moves synchronously along the X-axis, Δx=λ / 4, λ is the cathode spacing; the rotatable permanent magnet rotation rate v (rpm) and the planetary substrate movement speed v' (mm / s) satisfy v'=0.25v; (III) Multilayer coating strategy: First cycle: start cathode 1 and deposit MXene / ZnIn2S4 composite gas-sensitive material under argon atmosphere; Second cycle: switch to cathode 2 and introduce 5% O2 to modify surface oxygen vacancies; Third cycle: switch to cathode 3 and apply pulse bias to induce vertical orientation of nanosheets.

8. The coating method of the cathode array based on MXene / ZnIn2S4 composite gas-sensitive material according to claim 7, characterized in that: In step (i), the rotation speed of the rotatable permanent magnet is 0-120 rpm, the displacement accuracy of the planetary substrate is ±0.1 μm, the frequency of the pulse bias power supply is 1-100 kHz, and the duty cycle is 10-90%.

9. The coating method of the cathode array based on MXene / ZnIn2S4 composite gas-sensitive material according to claim 7, characterized in that: Step (iii) The thickness of the deposited MXene / ZnIn2S4 composite gas-sensitive material is 50 nm; the power of cathode 2 is 80 W, and the voltage of the pulse bias is 100 V.

10. The coating method of the cathode array based on MXene / ZnIn2S4 composite gas-sensitive material according to claim 7, characterized in that: The coating uniformity CV value of the MXene / ZnIn2S4 composite gas-sensitive material is ≤5%, and the target material utilization rate is ≥70%.

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