NL2030680B1

NL2030680B1 - Tin dioxide oxide thin film, preparation method thereof and application thereof in hydrogen detection

Info

Publication number: NL2030680B1
Application number: NL2030680A
Authority: NL
Inventors: Baofeng Zhao; Haibin Guan; Shuyuan Wang; Angang Song; Di Zhu; Dan Xu
Original assignee: Energy Res Inst Shandong Academy Sciences
Priority date: 2021-04-14
Filing date: 2022-01-25
Publication date: 2022-10-28
Also published as: CN113136547B; NL2030680A; CN113136547A

Abstract

The present disclosure discloses a tin dioxide oxide thin film, a preparation method thereof and an application thereof in hydrogen detection, wherein the tin dioxide oxide thin film has a crystal phase structure of rutile structure, and, at room temperature, the resistance before introduction of hydrogen is 80 to 100 Q and the resistance after introduction of hydrogen is 50 to 70 Q. The preparation method thereof is as follows: tin is made into a deposited tin dioxide thin film by means of distal plasma sputtering, and then annealing is performed and a rutile tin dioxide thin film is thus obtained, the obtained rutile tin dioxide thin film being the target tin dioxide oxide thin film. The tin dioxide thin film provided in this disclosure has excellent gas sensitivity to hydrogen at room temperature.

Description

i TIN DIOXIDE OXIDE THIN FILM, PREPARATION METHOD

THEREOF AND APPLICATION THEREOF IN HYDROGEN

DETECTION Technical Field The present disclosure relates to the technical field of thin film material and hydrogen detection, and relates to a tin dioxide oxide thin film, a preparation method thereof and an application thereof in hydrogen detection. Background Information in this part is disclosed merely for better understanding of the overall background of the present disclosure, and shall not necessarily be deemed to acknowledge or imply in any way that the information constitutes prior art known to ordinary technicians in this field. Tin dioxide (SnO:) 1s a metal oxide semiconductor widely used as a gas sensor, for 1t can be used to detect flammable gases such as methane, hydrogen and carbon monoxide. In recent years, due to the increase in the use of liquefied petroleum gas and compressed natural gas, the frequency of accidental explosions caused by leakage is higher. As a result, monitoring and accurately measuring the leakage of explosive gases are crucial for avoiding such accidents. The development of gas sensor system can selectively detect and determine various combustible gases. Therefore, a considerable part of the current researches have been devoted to the development of stable, pure or doped tin dioxide sensors. The tin dioxide gas sensor mainly includes processes of chemical adsorption and surface chemical reactions occurring with the involvement of lattice oxygen. The surface reaction between pre-adsorbed surface oxygen and reducing gas will cause changes in the conductivity of n-type SnO,, so the changes in resistance can be used for the detection of various gases with reducibility.

At present, researchers have adopted many methods to modify characteristics of sensors for sensing these semiconductor oxide gases so as to achieve high sensitivity and selectivity, for instance, the use of different additives can enhance the response rate, as well as the selectivity to a single gas, and the adoption of a physical or chemical filter can enhance the reaction rate of gases with weak gas sensitivity or regulate different working temperatures. Discovered in the researches of the present disclosure, current detection of hydrogen by using the tin dioxide gas sensor requires high temperature (>100°C). The gas sensor mainly plays the role of detecting the gas compositions. As a clean energy source, hydrogen has promising application prospects, but the storage or use temperature of hydrogen has to be 100°C or lower. Therefore, existing tin dioxide gas sensors cannot detect hydrogen storage, as a result of which popularization and application of tin dioxide gas sensors are hindered. Summary of the Invention In order to overcome shortcomings of the prior art, the object of the present disclosure is to provide a tin dioxide oxide thin film, a preparation method thereof and an application thereof in hydrogen detection. The tin dioxide oxide thin film provided in the present disclosure has excellent gas sensitivity to hydrogen at room temperature.

In order to realize the above object, the present disclosure adopts the following technical solution.

On the one hand, the present disclosure provides a tin dioxide oxide thin film with a crystal phase structure of rutile structure, wherein, at room temperature, the resistance before introduction of hydrogen is 80 to 100 €2, and the resistance after introduction of hydrogen is 50 to 70 Q.

When tin dioxide 1s in contact with hydrogen, the negatively charged oxygen adsorbed on the surface of the tin dioxide will react with hydrogen, and released electrons will be transferred to the conduction band of the tin dioxide crystal grains again, resulting in increased conductivity and reduced resistance of tin dioxide, wherein the sensitivity detection to hydrogen can be realized through the reduction of resistance.

Therefore, the main factors affecting the sensitivity of tin dioxide to hydrogen are as follows: 1. the resistance of tin dioxide itself, and 2. the reaction rate of negatively charged oxygen on the surface of tin dioxide with hydrogen.

If the resistance of tin dioxide is too high, the reaction rate of negatively charged oxygen on the surface of tin dioxide with hydrogen will be over low, which causes insignificant changes in resistance.

Therefore, the tin dioxide gas sensor in the prior art basically enhances the reaction rate of negatively charged oxygen on the surface of tin dioxide with hydrogen by heating up, so that the resistance of the tin dioxide changes significantly, thereby realizing the sensitivity detection to hydrogen.

The tin dioxide oxide thin film provided by the present disclosure has low resistance at room temperature, which is only 80 to 100 Q; moreover, its microstructure helps to enhance the reaction rate of negatively charged oxygen on the surface of tin dioxide with hydrogen at room temperature, so that the resistance drops to 50 to 70 © after hydrogen is introduced. Compared with its own low resistance, the resistance drop is more obvious, thereby realizing the sensitivity detection to hydrogen at room temperature.

On the other hand, the present disclosure provides a method for preparmg a tin dioxide oxide thin film, wherein tin is made into a deposited tin dioxide thin film by means of distal plasma sputtering, and then annealing is performed to obtain a rutile tin dioxide thin film. The obtained rutile tin dioxide thin film is the target tin dioxide oxide thin film.

Due to this method provided in the present disclosure, the resistance of the tin dioxide thin film itself, which is only 80 to 100 Q at room temperature, is reduced; moreover, the formed special microstructure enhances the reaction rate of 15s negatively charged oxygen on the surface of tin dioxide with hydrogen at room temperature so that the resistance drops to 50 to 70 Q after the introduction of hydrogen, and the change in resistance 1s more obvious, thereby realizing the sensitivity detection to hydrogen at room temperature.

A third aspect of the present disclosure provides an application of the above-mentioned tin dioxide oxide thin film in hydrogen detection.

A fourth aspect of the present disclosure provides a hydrogen gas sensor comprising a gas-sensitive element and a fixing frame, wherein the gas-sensitive element is mounted on the fixing frame, and the gas-sensitive element 1s the above-mentioned tin dioxide oxide thin film.

A fifth aspect of the present disclosure provides a method for hydrogen detection, wherein a to-be-measured gas containing hydrogen is made to pass through the above-mentioned tin dioxide oxide thin film, and the resistance change 5 of the tin dioxide oxide thin film is detected.

The beneficial effects of the present disclosure are as follows:

1. The present disclosure adopts distal plasma sputtering and annealing, as a result, the resistance of the tin dioxide thin film itself is reduced, and a special microstructure 1s formed to enhance the reaction rate of negatively charged oxygen on the surface of tin dioxide with hydrogen at room temperature, so that the tin dioxide thin film is sensitive to hydrogen at room temperature.

2. The preparation method of the present disclosure has high sputtering speed, low sputtering temperature, good repeatability, low energy consumption and low production cost, and is suitable for popularization and application.

Description of Drawings As a part of the present disclosure, the drawings of the description are provided for better understanding of the present disclosure, and schematic examples and illustrations thereof are to explain the present disclosure, rather than constituting improper limits of the present disclosure.

Fig. 1 shows X-ray diffraction spectra of rutile SnO; thin film in Examples 1, 2 and 3 at different annealing temperatures;

Fig. 2 shows an X-ray diffraction spectrum of the deposited SnO, thin film prepared in Contrast Example 1; Fig. 3 shows scanning electron microscope spectra at different magnifications of the rutile SnO; thin film in an experimental example; Fig.4 shows a high resolution transmission electron microscope spectrum of the rutile SnO; thin film in an experimental embodiment; Fig. 5 shows an EDS energy spectrum of the rutile SnO, thin film in an experimental example; Fig. 6 shows an XPS spectrum of Sn3d of the rutile SnO, thin film in an experimental example; Fig. 7 shows XPS spectra of Ols of the rutile SnO, thin film m an experimental example; Fig. 8 shows a gas-sensitivity spectrum of the rutile SnO; thin film m an experimental example; Fig. 9 shows a gas-sensitivity spectrum of the deposited SnO, thin film in an experimental example.

Embodiments It should be pomted out that the following detailed descriptions are all exemplary, and are intended to further explain the present disclosure.

Unless otherwise indicated, all technical and scientific terms used in this text have the same meaning as commonly understood by those ordinary technicians in the technical field to which the present disclosure belongs.

; It should be noted that the terms used here are only for describing specific embodiments, and are not intended to limit the exemplary embodiments based on the present disclosure. Unless otherwise clearly indicated in the context, the singular form in this text is also intended to include the plural form. In addition, it should also be understood that the terms “comprising” and/or “including” used 1n this specification indicate features, steps, operations, devices, components, and/or combinations thereof.

Based on the fact that existing tin dioxide gas sensors can hardly be used for hydrogen detection at room temperature, the present disclosure provides a tin dioxide oxide thin film, a preparation method thereof and an application thereof in hydrogen detection.

A typical embodiment of the present disclosure provides a tin dioxide oxide thin film with a crystal phase structure of rutile structure, wherein, at room temperature, the resistance before introduction of hydrogen is 80 to 100 Q, and the resistance after introduction of hydrogen 1s 50 to 70 Q.

The tin dioxide oxide thin film provided by the present disclosure has low resistance at room temperature, which is only 80 to 100 Q; moreover, its microstructure helps to enhance the reaction rate of negatively charged oxygen on the surface of tin dioxide with hydrogen at room temperature, so that the resistance drops to 50 to 70 Q after hydrogen is introduced. Compared with its own low resistance, the resistance drop is more obvious, thereby realizing the sensitivity detection to hydrogen at room temperature.

The room temperature in the present disclosure refers to the temperature of an indoor environment, which is usually 15 to 30°C.

In some examples of this embodiment, the resistance before introduction of hydrogen is 80 to 85 Q.

In some examples of this embodiment, the resistance after introduction of hydrogen is 65 to 70 Q.

Another embodiment of the present disclosure provides a method for preparing a tin dioxide oxide thin film, wherein tin is made into a deposited tin dioxide thin film by means of distal plasma sputtering, and then annealing is performed and a rutile tin dioxide thin film is thus obtained. The obtained rutile tin dioxide thin film is the target tin dioxide oxide thin film.

Due to this method provided in the present disclosure, the resistance of the tin dioxide thin film itself, which is only 80 to 100 Q at room temperature, is reduced; moreover, the formed special microstructure enhances the reaction rate of negatively charged oxygen on the surface of tin dioxide with hydrogen at room 15s temperature so that the resistance drops to 50 to 70 Q after the introduction of hydrogen, and the change in resistance 1s more obvious, thereby realizing the sensitivity detection to hydrogen at room temperature.

In addition, experiments have shown that deposited tin dioxide made by means of distal plasma sputtering has no gas sensitivity to hydrogen at room temperature, and only the rutile tin dioxide thin film prepared after annealing has gas sensitivity to hydrogen.

In some examples of this embodiment, the annealing temperature is 300 to 500°C. It can be ensured that the deposited tin dioxide is fully converted into rutile tin dioxide, and, meanwhile, the formed microscopic morphology is more helpful to enhance the reaction rate of negatively charged oxygen on the surface of the tin dioxide with hydrogen at room temperature. In some examples of this embodiment, oxygen 1s a reactive gas in distal plasma sputtering. The flow rate of oxygen is 1 to 10 sccm (standard milliliters per minute). Oxygen is preferably a high-purity gas with a purity of not less than

99.999%. In some examples of this embodiment, argon gas is a plasma gas source in distal plasma sputtering. The flow rate of argon is 50 to 100 sccm. Argon is preferably a high-purity gas with a purity of not less than 99.999%. In some examples of this embodiment, a power of plasma emission source in distal plasma sputtering is 300 to 500 W. In some examples of this embodiment, an accelerating bias power of target material in distal plasma sputtering is 50 to 100 W. In some examples of this embodiment, a pressure in a sputtering chamber in distal plasma sputtering is 2 to 5x10 mbar. In some examples of this embodiment, a sputtering speed in distal plasma sputtering is 10 to 50 nm/min, and sputtering time is 10 to 20 min. In some examples of this embodiment, a sputtering temperature is 20 to 50°C in distal plasma sputtering, and a temperature of a substrate is room temperature. The processes of reactive sputtering and that of deposition of the thin film are both carried out at room temperature or lower temperature, and there is no need to heat the substrate; moreover, the sputtering process 1s simpler and easy to control. The room temperature mentioned in the present disclosure refers to a general temperature, which is usually 24 to 26°C. The present disclosure adopts the distal plasma sputtering to perform the reactive sputtering, namely, oxygen is continuously introduced as a reactive gas during the sputtering process so as to combine and react with sputtered target material particles in the air, and then the reaction product flies to the substrate under the action of the acceleration bias applied onto the substrate bottom and adheres to the surface of the substrate, thereby depositing and forming a compact nano thin film.

The substrate 1s a glass substrate. The glass substrate is cleaned before use, wherein the cleaning 1s to place the glass substrate in acetone, isoacetone, ethanol, and deionized water in sequence for ultrasonic cleaning, wherein the cleaning lasts for 15 minutes each time at a cleaning temperature of 50°C. After cleaning, blow the substrate dry with a nitrogen gun or wipe the substrate dry with a dust-free cloth, and then put it into the sputtering chamber of the distal plasma sputtering system, getting it ready for sputtering. Before reactive sputtering, vacuum the sputtering chamber. Introduce a certain flow of argon into the chamber, and then introduce oxygen after the pressure in the chamber remains stable.

A third embodiment of the present disclosure provides an application of the above-mentioned tin dioxide oxide thin film in hydrogen detection.

A fourth embodiment of the present disclosure provides a hydrogen gas sensor comprising a gas-sensitive element and a fixing frame, wherein the gas-sensitive element 1s mounted on the fixing frame, and the gas-sensitive tl element 1s the above-mentioned tin dioxide oxide thin film.

The fifth embodiment of the present disclosure provides a method for hydrogen detection, wherein a to-be-measured gas containing hydrogen is made to pass through the above-mentioned tin dioxide oxide thin film, and the resistance change of the tin dioxide oxide thin film is detected.

For clearer understanding of the present disclosure by those skilled in the art, the technical solutions of the present disclosure will be described in detail with reference to specific examples and contrast examples.

In a specific embodiment, the target material used is a tin target material with a diameter of 3 inches and a thickness of 6 mm.

Example 1 The preparation method of the rutile SnO: thin film in this example includes the following steps of: 1) cleaning the glass substrate: place the glass substrate in acetone, 1soacetone, ethanol, and deionized water in sequence for ultrasonic cleaning, wherein the cleaning lasts for 20 minutes each time at a cleaning temperature of 50°C; after ultrasonic cleaning, wipe the glass substrate dry with a dust-free cloth, and finally put it into the sputtering chamber of the distal plasma sputtering system, getting it ready for sputtering; 2) sputtering: use argon as the plasma source and oxygen as the reactive gas, and adopt the distal plasma sputtering technology to deposit a thin film on the glass substrate by means of reactive sputtering, specifically: before reactive sputtering, vacuum the sputtering chamber of the distal plasma sputtering system to 2x10 mbar, then introduce 80 sccm of argon into the chamber, and turn on the plasma source emission system when a pressure inside the chamber is stable, so as to generate plasma at the plasma source; turn on the plasma bunching electromagnet so that the plasma bombard the target material, thereby pre-sputtering the target material; introduce oxygen into the chamber at a flow rate of 10 sccm, wherein the pressure in the sputtering chamber is 4x10 mbar, and both the argon and oxygen used are high-purity gases with a purity of not less than 99.999%; when the pressure and the voltage inside chamber are stable, open a baffle clinging underneath the glass substrate and start reactive sputtering to deposit the thin film; during the reactive sputtering, the power of the plasma emission source is 500 W, the accelerating bias power of the target material 1s 100 W, the sputtering speed is 20 nm/min, the sputtering time 1s 20 min, the sputtering temperature 1s 20°C, and the temperature of the glass substrate is room temperature; wherein the sputtering target material is a tin target material (with a purity of 5 N); and after the reactive sputtering, close the baffle under the glass substrate, and a layer of nano thin film has been deposited on the glass substrate, i.e. a semi-finished product; and 3) place the semi-finished product obtained in step 2) into a rapid annealing furnace in air atmosphere, and perform rapid annealing at 300°C for 1 hour, and then cool it naturally to room temperature, thereby obtaining the rutile SnO, thin film.

Example 2

The preparation method of the rutile SnO; thin film in this example includes the following steps of:

1) cleaning the glass substrate: place the glass substrate in acetone, isoacetone,

ethanol, and deionized water in sequence for ultrasonic cleaning, wherein the cleaning lasts for 20 minutes each time at a cleaning temperature of 50°C; after ultrasonic cleaning, wipe the glass substrate dry with a dust-free cloth, and finally put it into the sputtering chamber of the distal plasma sputtering system, getting it ready for sputtering;

2) sputtering: use argon as the plasma source and oxygen as the reactive gas, and adopt the distal plasma sputtering technology to deposit a thin film on the glass substrate by means of reactive sputtering, specifically:

before reactive sputtering, vacuum the sputtering chamber of the distal plasma sputtering system to 2x10% mbar, then introduce 80 sccm of argon into the chamber, and turn on the plasma source emission system when a pressure inside the chamber is stable, so as to generate plasma at the plasma source; turn on the plasma bunching electromagnet so that the plasma bombard the target material, thereby pre-sputtering the target material;

introduce oxygen into the chamber at a flow rate of 10 sccm, wherein the pressure in the sputtering chamber is 4x10 mbar, and both the argon and oxygen used are high-purity gases with a purity of not less than 99.999%; when the pressure and the voltage inside chamber are stable, open a baffle clinging underneath the glass substrate and start reactive sputtering to deposit the thin film;

during the reactive sputtering, the power of the plasma emission source 1s 500 W, the accelerating bias power of the target material is 100 W, the sputtering speed 1s 20 nm/min, the sputtering time 1s 20 min, the sputtering temperature 1s 20°C, and the temperature of the glass substrate is room temperature; wherein the sputtering target material is a tin target material (with a purity of 5 N); and after the reactive sputtering, close the baffle under the glass substrate, and a layer of nano thin film has been deposited on the glass substrate, ie. a semi-finished product; and 3) place the semi-finished product obtained in step 2) into a rapid annealing furnace in air atmosphere, and perform rapid annealing at 400°C for 1 hour, and then cool naturally it to room temperature, thereby obtaining the rutile SnO, thin film.

Example 3 The preparation method of the rutile SnO; thin film in this example includes the following steps of: 1) cleaning the glass substrate: place the glass substrate in acetone, isoacetone, ethanol, and deionized water in sequence for ultrasonic cleaning, wherein the cleaning lasts for 20 minutes each time at a cleaning temperature of 50°C; after ultrasonic cleaning, wipe the glass substrate dry with a dust-free cloth, and finally put it into the sputtering chamber of the distal plasma sputtering system, getting it ready for sputtering; 2) sputtering: use argon as the plasma source and oxygen as the reactive gas,

and adopt the distal plasma sputtering technology to deposit a thin film on the glass substrate by means of reactive sputtering, specifically: before reactive sputtering, vacuum the sputtering chamber of the distal plasma sputtering system to 2x10 mbar, then introduce 80 sccm of argon into the chamber, and tum on the plasma source emission system when a pressure inside the chamber is stable, so as to generate plasma at the plasma source; turn on the plasma bunching electromagnet so that the plasma bombard the target material, thereby pre-sputtering the target material; introduce oxygen into the chamber at a flow rate of 10 sccm, wherein the pressure in the sputtering chamber is 4x10°% mbar, and both the argon and oxygen used are high-purity gases with a purity of not less than 99.999%; when the pressure and the voltage inside chamber are stable, open a baffle clinging underneath the glass substrate and start reactive sputtering to deposit the thin film; during the reactive sputtering, the power of the plasma emission source is 500 W, the accelerating bias power of the target material 1s 100 W, the sputtering speed 1s 20 nm/min, the sputtering time is 20 min, the sputtering temperature 1s 20°C, and the temperature of the glass substrate is room temperature; wherein the sputtering target material 1s a tin target material (with a purity of 5 N); and after the reactive sputtering, close the baffle under the glass substrate, and a layer of nano thin film has been deposited on the glass substrate, i.e. a semi-finished product; and 3) place the semi-finished product obtained in step 2) into a rapid annealing furnace in air atmosphere, and perform rapid annealing at 500°C for 1 hour, and then cool naturally to room temperature, thereby obtaining the rutile SnO; thin film. Experimental Example In this Experimental Example, the rutile tin dioxide thin films obtained in Examples 1, 2 and Contrast Examples are detected, and the results are as follows.

Fig. 1 shows X-ray diffraction spectra of rutile SnO; thin films obtained in Examples 1, 2 and 3. As shown in Fig. 1, the phase structure of all SnO, thin films obtained in the present disclosure are rutile tin dioxide, and there is no impurity. As a result, the SnO» thin film obtained in the present disclosure 1s excellent in chemical stability and mechanical strength.

Fig. 3 shows SEM spectra of the rutile SnO; thin film in Example 2 at different magnifications. As shown in Fig. 3, the surface of the thin film 1s very smooth, flat, uniform and compact.

Fig.4 shows a high resolution TEM spectrum of the SnO; thin film in Example 2. As shown in Fig. 4, all of the thin films have been crystallized, the crystallization property is excellent, and rutile phase is formed.

Fig. 5 shows an EDS energy spectrum of the rutile SnO; thin film in Example 2, wherein the tin-oxygen atomic ratio in the film is about 1:2.

Fig. 6 shows an XPS spectrum of Sn3d of the rutile SnO; thin film m Example 2. As shown in Fig. 6, in the SnO, thin film obtained in Example 2, tin has a valence of plus tetra, and is tin dioxide. The XPS spectrum shows that the symmetry of tin in spectrum 1s very good, and the tin element exists in a high valence state.

Fig. 7 shows XPS spectra of Ols of the rutile SnO, thin film in Example 2. After peak split to the Ols spectra, two peaks are obtained, and the binding energies are respectively 530 eV and 531.7 eV, respectively representing lattice oxygen and adsorbed oxygen.

The tin dioxide film 1s used for hydrogen sensitivity test, in which the response and recovery time, sensitivity and other properties are tested. This test system 1s a set of self-assembled instruments, which includes the following four main parts: (1) a terminal data acquisition system; Keithley 2400 is used to monitor test signals, and collect and transmit signals to the computer for processing; the computer supporting software controls the 2400, so as to change the size of the current, turn on and off the instrument, draw real-time drawing for data obtained from the test, display the final result and obtain the test data; (2) a gas storage and test chamber; the chamber used in the present disclosure is a modified high-temperature vacuum furnace, wherein a pair of air inlet and air outlet are provided in the chamber, and the furnace can be highly vacuumed so as to be used for testing the gas sensitivity under vacuum conditions; (3) a gas flow controller; during hydrogen test, hydrogen is generally tested at different concentrations so as to detect the accuracy of the sensor, and a flowmeter will be needed for controlling at this moment; the volume of the chamber for storing the gas 1s known, and the gas concentration can be detected by controlling the gas flow rate and the deflation time; in addition, hydrogen is flammable and explosive, and is easy to explode when the hydrogen concentration is greater than 4%, so the flowmeter can also perform effective detection and avoid dangers caused by excessive hydrogen concentration; (4) gas sources; the gas cylinders containing the gases are purchased directly from the manufacturers, and the instrument is equipped with two gas cylinders: pure argon and hydrogen-argon mixed gas, wherein the ratio of hydrogen to argon in the mixed gas 1s 1:4.

Fig. 8 shows a gas-sensitivity spectrum of the rutile SnO: thin film in Example 2. As shown in Fig. 8, the resistance of SnO: thin film is only 80.3 Q before introduction of hydrogen, and reduces to 68 Q when hydrogen (100 ppm) is introduced to the surface of the SnO, thin film, and the resistance increases when the introduction of hydrogen is stopped, showing excellent gas sensitivity.

Contrast Example 1 The preparation method of the deposited SnO, thin film mn this contrast example includes the following steps of: 1) cleaning the glass substrate: place the glass substrate in acetone, 1soacetone, ethanol, and deionized water in sequence for ultrasonic cleaning, wherein the cleaning lasts for 20 minutes each time at a cleaning temperature of 50°C; after ultrasonic cleaning, wipe the glass substrate dry with a dust-free cloth, and finally put it into the sputtering chamber of the distal plasma sputtering system, getting it ready for sputtering; 2) sputtering: use argon as the plasma source and oxygen as the reactive gas, and adopt the distal plasma sputtering technology to deposit a thin film on the glass substrate by means of reactive sputtering, specifically: before reactive sputtering, vacuum the sputtering chamber of the distal plasma sputtering system to 2x10 mbar, then introduce 80 scem of argon into the chamber, and turn on the plasma source emission system when a pressure inside the chamber is stable, so as to generate plasma at the plasma source; turn on the plasma bunching electromagnet so that the plasma bombard the target material, thereby pre-sputtering the target material; introduce oxygen into the chamber at a flow rate of 10 sccm, wherein the pressure in the sputtering chamber is 4x10 mbar, and both the argon and oxygen used are high-purity gases with a purity of not less than 99.999%; when the pressure and the voltage inside chamber are stable, open a baffle clinging underneath the glass substrate and start reactive sputtering to deposit the thin film; during the reactive sputtering, the power of the plasma emission source is 500 W, the accelerating bias power of the target material is 100 W, the sputtering speed is 20 nm/min, the sputtering time 1s 20 min, the sputtering temperature 1s 20°C, and the temperature of the glass substrate is room temperature; wherein the sputtering target material is a tin target material (with a purity of 5 N); and after the reactive sputtering, close the baffle under the glass substrate, and a layer of nano thin film has been deposited on the glass substrate, i.e. the deposited Sn0: thin film.

Fig. 4 shows the X-ray diffraction spectrum of the obtained deposited SnO, thin film. It can be seen that the film is non-crystal. The film deposited by direct sputtering at room temperature does not crystallize, because the thermodynamic conditions for forming SnO; crystals are not satisfied, and it is thus hard for crystal nuclei to form or grow, and is impossible to form a stable crystal structure.

The above gas sensitivity experiment was carried out, and the results are shown in Fig. 9, wherein: at room temperature, the resistance of the thin film 1s 820 Q before introduction of hydrogen, and there is basically no change to the resistance of the thin film when hydrogen is introduced onto the surface of the SnO; thin film. Contrast Example 2 In this contrast example, the tin dioxide thin film is prepared by means of sol-gel method, including the following steps of: (1) taking 1.13 g of SnCl;:2H;0 and pouring it into a conical flask containing 50 mL of anhydrous ethanol, thereby obtaining Sn0: solution of 0.1 mol/L; (2) stirring the solution at room temperature for 3 h, and keeping the solution still for 24 h, thereby obtaining a colorless and transparent colloidal solution; (3) performing spin coating after passing through acetone, alcohol, deionized water and drying, drying for 10 min at 100°C, and repeating these procedures 10 times, thereby obtaining a gel having a certain thickness; and (4) putting a sample into a tube heating furnace for sintering at a sintering temperature of 500°C for 2 h, and then cooling it naturally, thereby obtaining a SnO; nano film.

The results of the above gas sensitivity experiment show that, at room temperature, the resistance is extremely high (greater than 200 kQ) without introduction of hydrogen, and there is basically no change in the resistance with the introduction of hydrogen.

The afore-mentioned descriptions are merely preferable examples, and are not intended to limit the present disclosure.

For those skilled in the art, there can be various modifications and changes for the present disclosure.

Within the spirit and principle of the present disclosure, any modification, equivalent replacement, improvement, etc. shall be included in the protection scope of the present invention.

EMBODIMENTS

1. A tin dioxide oxide thin film with a crystal phase structure of rutile structure, wherein, at room temperature, the resistance before introduction of hydrogen is 80 to 100 ©, and the resistance after introduction of hydrogen is 50 to 70 Q.

2. The tin dioxide oxide thin film according to claim 1, wherein the resistance before introduction of hydrogen is 80 to 85 ©; or, the resistance after introduction of hydrogen is 65 to 70 Q.

3. A method for preparing a tin dioxide oxide thin film, wherein tin is made into a deposited tin dioxide thin film by means of distal plasma sputtering, and then annealing 1s performed and a rutile tin dioxide thin film 1s thus obtained.

4. The method for preparing a tin dioxide oxide thin film according to claim 3, wherein the annealing temperature is 300 to 500°C.

5. The method for preparing a tin dioxide oxide thin film according to claim 3, wherein oxygen is a reactive gas in distal plasma sputtering, and a flow rate of oxygen is I to 10 sccm; or, argon gas is a plasma gas source in distal plasma sputtering and a flow rate of argon is 50 to 100 sccm.

6. The method for preparing a tin dioxide oxide thin film according to claim 3, wherein a power of plasma emission source in distal plasma sputtering is 300 to 500 W; or, an accelerating bias power of target material in distal plasma sputtering is 50 to 100 W.

7. The method for preparing a tin dioxide oxide thin film according to claim 3, wherein a pressure in a sputtering chamber in distal plasma sputtering is 2 to 5x10 mbar; or, a sputtering speed in distal plasma sputtering 1s 10 to 50 nm/min, and sputtering time 1s 10 to 20 min; or, a sputtering temperature 1s 20 to 50°C in distal plasma sputtering, and a temperature of a substrate 1s room temperature.

8. An application of the tin dioxide oxide thin film according to claim 1 or 2,0r the tin dioxide oxide thin film prepared by means of the method according to any one of claims 3 to 7 in hydrogen detection.

9. A hydrogen gas sensor, comprising a gas-sensitive element and a fixing frame, wherein the gas-sensitive element is mounted on the fixing frame, and the gas-sensitive element is the tin dioxide oxide thin film according to claim 1 or 2, or the tin dioxide oxide thin film prepared by means of the method according to any one of claims 3 to 7.

10. A method of gas detection, wherein a to-be-measured gas containing hydrogen is made to pass through the tin dioxide oxide thin film according to claim l or 2 or the tin dioxide oxide thin film prepared by means of the method according to any one of claims 3 to 7, so as to detect the resistance change of the tin dioxide oxide thin film.

Claims

CONCLUSIONS

A tin dioxide oxide thin film having a crystal phase structure of rutile structure, wherein the resistance before hydrogen introduction at room temperature is 80 to 100 Ω, and the resistance after hydrogen introduction is 50 to 70 Ω.

2. The tin dioxide oxide thin film according to claim 1, wherein the hydrogen introduction resistance is 80 to 85 Ω; whether the resistance after introduction of hydrogen is 65 to 70 Ω.

3. A method for preparing a tin dioxide oxide thin film, wherein tin is made into a precipitated tin dioxide thin film by distal plasma sputtering, and then annealing is applied, thus obtaining a tin dioxide rutile thin film.

The method for preparing a tin dioxide oxide thin film according to claim 3, wherein the annealing temperature is 300 to 500°C.

The method for preparing a tin dioxide oxide thin film according to claim 3, wherein oxygen is a reactive gas in distal plasma sputtering 1s, and a flow rate of oxygen is 1 to 10 scem; or, argon gas is a plasma gas source in distal plasma sputtering and the flow rate of argon is 50 to 100 sccm.

The method for preparing a tin dioxide oxide thin film according to claim 3, wherein the power of a plasma emission source in distal plasma sputtering is 300 to 500 W; or an accelerating bias force of target material at distal plasma sputtering 50 to 100 W 1s.

The method for preparing a tin dioxide oxide thin film according to claim 3, wherein a pressure in a sputtering chamber in distal plasma sputtering is 2 to 510% mbar; or a sputtering rate in distal plasma sputtering is 10 to 50 nm/min, and sputtering time is 10 to 20 minutes; or a sputtering temperature of 20 to 50°C 1s in distal plasma sputtering, and a temperature of a substrate is room temperature.

8. An use of the tin dioxide oxide thin film according to claims 1 or 2, or the tin dioxide oxide thin film prepared by the method according to any one of claims 3 to 7 in hydrogen detection.

9. A hydrogen gas sensor comprising a gas-sensitive element and a fixed frame, the gas-sensitive element being attached to the fixed frame, and the gas-sensitive element being the tin dioxide oxide thin film according to claim 1 or 2, or the tin dioxide oxide thin film prepared by of the method according to any one of claims 3 to 7.

10. A method of gas detection, wherein a gas to be measured consisting of hydrogen is passed through the thin film of tin dioxide according to claim 1 or 2 or prepared through the thin film of tin dioxide by the method according to any one of claims 3 to 7, so that the resistance change of the tin dioxide thin film is detected.