Nb2o5 nano-hydrogen sensor, preparation method and application thereof
By preparing a porous structure for the Nb2O5 nano-hydrogen sensor and subjecting it to heat treatment in a hydrogen-containing atmosphere, the problem of insufficient sensitivity and selectivity of the Nb2O5 hydrogen sensor at low temperatures was solved, achieving efficient and stable hydrogen detection and improving the sensor's response speed and service life.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- EAST CHINA UNIV OF SCI & TECH
- Filing Date
- 2026-04-21
- Publication Date
- 2026-06-12
AI Technical Summary
Existing Nb2O5 hydrogen sensors lack sufficient sensitivity and selectivity at low temperatures and are responsive to other reducing gases, making it difficult to achieve efficient and stable hydrogen detection in complex environments.
By depositing an Nb2O5 layer on the substrate surface and then performing heat treatment in an oxygen-containing atmosphere to form a porous structure, and further processing in a hydrogen-containing atmosphere, the sensitivity and selectivity of the sensor are improved, the adsorption and redox reactions of hydrogen are enhanced, the interface charge and stress changes are buffered, and the service life is extended.
The prepared Nb2O5 nano-hydrogen sensor exhibits high sensitivity, good selectivity and long-term stability at 250℃, and can reliably detect hydrogen with fast response and long service life.
Smart Images
Figure CN122193319A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of hydrogen detection technology, specifically relating to an Nb2O5 nano-hydrogen sensor, its preparation method, and its application. Background Technology
[0002] Hydrogen is a colorless, odorless, and non-toxic gas with advantages such as high calorific value, wide availability, and clean combustion products, and has been widely used in various fields such as metal smelting, aircraft, and new energy vehicles. However, hydrogen is extremely prone to leakage and has a lower explosive limit of only 4 vol%, making it highly susceptible to combustion and explosion accidents in air, and its presence is undetectable by the human eye or smell. Under real-world testing conditions, hydrogen sensors often fail under varying temperature and humidity conditions. Therefore, to ensure safety during production and use, there is an urgent need to develop a hydrogen sensor with high sensitivity, high selectivity, and stable reliability at a specific temperature for real-time monitoring of hydrogen concentration in the environment.
[0003] Nb₂O₅, as a MOS-type hydrogen sensor material, possesses a high melting point, high chemical stability, controllable defect structure, and excellent drift resistance, making it particularly suitable for hydrogen detection in high-temperature, long-life, and demanding operating environments. However, Nb₂O₅ alone exhibits a slow response to hydrogen, typically requiring relatively high operating temperatures for effective monitoring. It also shows some response to other reducing gases (such as CO and CH₄), leading to insufficient sensitivity and selectivity. Therefore, improving Nb₂O₅ to enhance the sensitivity and selectivity of hydrogen sensors at lower temperatures remains a significant challenge in this field. Summary of the Invention
[0004] The purpose of this invention is to provide an Nb₂O₅ nano-hydrogen sensor, its preparation method, and its applications. The hydrogen sensor prepared by this invention operates at a low temperature (250°C) and exhibits excellent sensitivity and selectivity.
[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing an Nb₂O₅ nano-hydrogen sensor, comprising the following steps: (1) An adhesion layer and an electrode are sequentially deposited on the substrate surface by photolithography patterning and radio frequency magnetron sputtering to obtain a substrate containing electrodes; (2) In step (1), a contact layer and an Nb2O5 layer are sequentially deposited on the surface of the substrate containing the electrode by radio frequency magnetron sputtering to obtain a substrate containing a sensitive layer; (3) The substrate containing the sensitive layer obtained in step (2) is subjected to oxygen-containing atmosphere heat treatment to obtain Nb2O5 nano hydrogen sensor.
[0006] Preferably, the substrate in step (1) is a silicon wafer containing a silicon dioxide layer; the thickness of the silicon dioxide layer is 280~320nm.
[0007] Preferably, the material of the adhesion layer in step (1) is Ti or Cr; the thickness of the adhesion layer is 10~30nm.
[0008] Preferably, the electrode material in step (1) is Pt or Au; the thickness of the electrode is 100~300nm.
[0009] Preferably, the thickness of the contact layer in step (2) is 5~15nm.
[0010] Preferably, the thickness of the Nb2O5 layer in step (2) is 400~600nm.
[0011] Preferably, the temperature of the oxygen-containing atmosphere heat treatment in step (3) is 550~650℃, and the time of the oxygen-containing atmosphere heat treatment is 1~5h.
[0012] Preferably, after the oxygen-containing atmosphere heat treatment in step (3) is completed, a hydrogen-containing atmosphere heat treatment is also performed; the temperature of the hydrogen-containing atmosphere heat treatment is 400~700℃, and the time of the hydrogen-containing atmosphere heat treatment is 2~5h.
[0013] The present invention also provides a Nb2O5 nano-hydrogen sensor prepared by the preparation method described in the above technical solution.
[0014] This invention also provides the application of the Nb2O5 nano-hydrogen sensor described above in hydrogen detection.
[0015] This invention provides a method for fabricating a Nb2O5 nano-hydrogen sensor, comprising the following steps: (1) depositing an adhesion layer and an electrode sequentially on the surface of a substrate by photolithography patterning and radio frequency magnetron sputtering to obtain a substrate containing electrodes; (2) depositing a contact layer and an Nb2O5 layer sequentially on the surface of the substrate containing electrodes obtained in step (1) by radio frequency magnetron sputtering to obtain a substrate containing a sensitive layer; (3) subjecting the substrate containing the sensitive layer obtained in step (2) to oxygen-containing atmosphere heat treatment to obtain a Nb2O5 nano-hydrogen sensor. This invention involves heat-treating Nb₂O₅ nanofilms in an oxygen-containing atmosphere to prepare Nb₂O₅ nanomaterials with a porous structure. This structure has a large specific surface area and abundant pores, increasing the effective surface area and providing more active sites for hydrogen adsorption / desorption and redox reactions on the sensor surface. This promotes hydrogen adsorption and redox reactions. Simultaneously, the oxygen-containing atmosphere heat treatment eliminates intergranular stress generated during Nb₂O₅ film deposition and improves its crystallinity, thereby enhancing the sensor's sensitivity, response speed, and selectivity. Further heat treatment in a hydrogen-containing atmosphere following the oxygen-containing atmosphere heat treatment utilizes the reducing power of hydrogen to promote the formation of lattice oxygen vacancies on the Nb₂O₅ film surface, enhancing the dissociation and migration of hydrogen molecules on its surface, further significantly improving the Nb₂O₅'s response sensitivity and speed to hydrogen. In addition, this layer structure can buffer interfacial charge and stress changes during hydrogen adsorption and desorption, maintaining the stability of the active centers on the Nb₂O₅ surface and significantly extending the sensor's lifespan. The results of the embodiments show that the hydrogen sensor prepared by the present invention exhibits high sensitivity, good selectivity and long-term stability in a medium-high temperature environment (250°C), and can achieve reliable detection of hydrogen. Attached Figure Description
[0016] Figure 1 A top view schematic diagram of the Nb2O5 nano-hydrogen sensor structure prepared in this invention; Figure 2 This is a side view schematic diagram of the Nb2O5 nano-hydrogen sensor structure prepared in this invention; Figure 3 The sensitivity diagrams of the hydrogen sensors prepared in Example 1 and Comparative Examples 1-2 to hydrogen are shown. Figure 4 The sensitivity diagrams of the hydrogen sensors prepared in Examples 2 and Comparative Examples 3-6 to hydrogen are shown. Figure 5 The sensitivity diagrams of the hydrogen sensors prepared in Examples 2, 3-4 and Comparative Example 7 to hydrogen are shown. Figure 6 The sensitivity diagrams of the hydrogen sensors prepared in Examples 2, 3 and Comparative Example 8 to hydrogen are shown. Figure 7The graph shows the selectivity performance of the Nb2O5 nano-hydrogen sensor prepared in Example 3 against different gases at 1000 ppm. Figure 8 The graph shows the long-term stability performance of the Nb2O5 nano-hydrogen sensor prepared in Example 3 against 1000ppm hydrogen. Detailed Implementation
[0017] This invention provides a method for preparing an Nb₂O₅ nano-hydrogen sensor, comprising the following steps: (1) An adhesion layer and an electrode are sequentially deposited on the substrate surface by photolithography patterning and radio frequency magnetron sputtering to obtain a substrate containing electrodes; (2) In step (1), a contact layer and an Nb2O5 layer are sequentially deposited on the surface of the substrate containing the electrode by radio frequency magnetron sputtering to obtain a substrate containing a sensitive layer; (3) The substrate containing the sensitive layer obtained in step (2) is subjected to oxygen-containing atmosphere heat treatment to obtain Nb2O5 nano hydrogen sensor.
[0018] The present invention deposits an adhesion layer and an electrode sequentially on the substrate surface by photolithography patterning and radio frequency magnetron sputtering to obtain a substrate containing electrodes.
[0019] In this invention, the substrate is preferably a silicon wafer containing a silicon dioxide layer; the thickness of the silicon dioxide layer is preferably 280~320nm, more preferably 300nm.
[0020] The present invention does not impose any special limitation on the size of the substrate; it can be selected according to actual needs.
[0021] In an embodiment of the present invention, the substrate has a size of 10mm × 10mm.
[0022] In this invention, the substrate is preferably cleaned with acetone, washed with water, and dried in sequence before use.
[0023] The present invention does not impose any special limitations on the acetone cleaning, water washing and drying operations. Technical solutions well known to those skilled in the art can be used to remove contaminants and organic residues from the substrate surface to ensure the cleanliness of the substrate surface.
[0024] In this invention, the material of the adhesive layer is preferably Ti or Cr, more preferably Ti; the thickness of the adhesive layer is preferably 10~30nm, more preferably 20nm.
[0025] In this invention, the electrode is preferably made of Pt or Au, more preferably Pt; the electrode thickness is preferably 100~300nm, more preferably 200nm.
[0026] The present invention does not impose any special limitations on the photolithographic patterning operation; any technical solution known to those skilled in the art can be used.
[0027] In this invention, the power of the RF magnetron sputtering of the adhesion layer is preferably 50~110W, more preferably 100W. This invention does not have a specific limitation on the RF magnetron sputtering time of the adhesion layer, as long as the thickness of the adhesion layer is within the required range. This invention provides an adhesion layer to enhance the adhesion between the electrode and the substrate.
[0028] In this invention, the power of the RF magnetron sputtering of the electrode is preferably 45~55W, more preferably 50W. This invention does not impose a specific limitation on the RF magnetron sputtering time of the electrode, as long as the electrode thickness is within the required range.
[0029] After obtaining the substrate containing electrodes, the present invention deposits a contact layer and an Nb2O5 layer sequentially on the surface of the substrate containing electrodes by radio frequency magnetron sputtering to obtain a substrate containing a sensitive layer.
[0030] In this invention, the material of the contact layer is preferably Ti.
[0031] In this invention, the thickness of the contact layer is preferably 5-15 nm. As one embodiment, the thickness of the contact layer can specifically be 5 nm, 6 nm, 7 nm, 8 nm, 9 nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, or 15 nm. By controlling the thickness of the contact layer within the above range, this invention can further improve the performance of the sensor.
[0032] In this invention, the power of the RF magnetron sputtering of the contact layer is preferably 90~150W, more preferably 100W. This invention does not have a specific limitation on the RF magnetron sputtering time of the contact layer, as long as the thickness of the contact layer is within the required range.
[0033] In this invention, the thickness of the Nb₂O₅ layer is preferably 400-600 nm. As one embodiment, the thickness of the Nb₂O₅ layer can specifically be 400 nm, 410 nm, 420 nm, 430 nm, 440 nm, 450 nm, 460 nm, 470 nm, 480 nm, 490 nm, 500 nm, 520 nm, 550 nm, 580 nm, or 600 nm. By controlling the thickness of the Nb₂O₅ layer within the above range, this invention can further improve the performance of the sensor.
[0034] In this invention, the power of the radio frequency magnetron sputtering of the Nb2O5 layer is preferably 40~80W, more preferably 50W. This invention does not have a specific limitation on the time of the radio frequency magnetron sputtering of the Nb2O5 layer, as long as the thickness of the Nb2O5 layer is within the required range.
[0035] After obtaining the substrate containing the sensitive layer, the present invention performs oxygen-containing atmosphere heat treatment on the substrate containing the sensitive layer to obtain Nb2O5 nano hydrogen sensor.
[0036] In one embodiment, the oxygen-containing atmosphere heat treatment is carried out in an air atmosphere.
[0037] In this invention, the temperature of the oxygen-containing atmosphere heat treatment is preferably 550~650℃, more preferably 600℃; the time of the oxygen-containing atmosphere heat treatment is preferably 1~5h, more preferably 2h; and the rate of heating to the oxygen-containing atmosphere heat treatment temperature is preferably 4~6℃ / min, more preferably 5℃ / min.
[0038] After the oxygen-containing atmosphere heat treatment is completed, the present invention preferably further performs a hydrogen-containing atmosphere heat treatment to obtain an Nb2O5 nano-hydrogen sensor.
[0039] In this invention, the temperature of the hydrogen-containing atmosphere heat treatment is preferably 400~700℃, more preferably 400℃; the time of the hydrogen-containing atmosphere heat treatment is preferably 2~5h, more preferably 4h; and the rate of heating to the hydrogen-containing atmosphere heat treatment temperature is preferably 3~8℃ / min, more preferably 5℃ / min.
[0040] In this invention, the hydrogen-containing atmosphere heat treatment is preferably carried out in a mixed atmosphere of hydrogen and argon.
[0041] In this invention, the concentration of hydrogen in the mixed atmosphere of hydrogen and argon is preferably 400-600 ppm, more preferably 500 ppm.
[0042] This invention controls the temperature, time, and atmosphere of oxygen-containing atmosphere heat treatment and hydrogen-containing atmosphere heat treatment within the above-mentioned ranges, which can further improve the performance of the sensor.
[0043] After the heat treatment in a hydrogen atmosphere is completed, the present invention preferably cools the product of the heat treatment in a hydrogen atmosphere to obtain an Nb2O5 nano-hydrogen sensor.
[0044] The present invention does not impose any special limitations on the cooling operation; any technical solution known to those skilled in the art can be used to cool to room temperature.
[0045] This invention involves heat-treating Nb₂O₅ nanofilms in an oxygen-containing atmosphere to prepare Nb₂O₅ nanomaterials with a porous structure. This structure has a large specific surface area and abundant pores, increasing the effective surface area and providing more active sites for hydrogen adsorption / desorption and redox reactions on the sensor surface. This promotes hydrogen adsorption and redox reactions. Simultaneously, the oxygen-containing atmosphere heat treatment eliminates intergranular stress generated during Nb₂O₅ film deposition and improves its crystallinity, thereby enhancing the sensor's sensitivity, response speed, and selectivity. Further heat treatment in a hydrogen-containing atmosphere following the oxygen-containing atmosphere heat treatment utilizes the reducing power of hydrogen to promote the formation of lattice oxygen vacancies on the Nb₂O₅ film surface, enhancing the dissociation and migration of hydrogen molecules on its surface, further significantly improving the Nb₂O₅'s response sensitivity and speed to hydrogen. In addition, this layer structure can buffer interfacial charge and stress changes during hydrogen adsorption and desorption, maintaining the stability of the active centers on the Nb₂O₅ surface and significantly extending the sensor's lifespan.
[0046] A top view of the Nb₂O₅ nano-hydrogen sensor structure prepared by this invention is shown below. Figure 1 As shown, 1 is the substrate, 2 is the electrode, and 3 is the Nb2O5 sensitive layer nanofilm.
[0047] A side view of the Nb₂O₅ nano-hydrogen sensor structure prepared by this invention is shown below. Figure 2 As shown.
[0048] The present invention also provides a Nb2O5 nano-hydrogen sensor prepared by the preparation method described in the above technical solution.
[0049] This invention also provides the application of the Nb2O5 nano-hydrogen sensor described above in hydrogen detection.
[0050] The present invention does not impose any special limitations on the operation of the application, and any technical solution known to those skilled in the art can be used.
[0051] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0052] Example 1 A method for preparing an Nb2O5 nano-hydrogen sensor is as follows: (1) A silicon wafer (10mm×10mm) containing a silicon dioxide layer (thickness of 300nm) was used as a substrate. It was ultrasonically cleaned in acetone and deionized water for 5min each, and then dried with nitrogen gas (purity 99.99%) to obtain the treated substrate. (2) Use a dropper to uniformly drop photoresist NR77-6000PY onto the surface of the treated substrate, then spin coat at 3000 rpm for 60 s, pre-bake at 110 ℃ for 2 min, expose to ultraviolet light for 6 s, then post-bake at 110 ℃ for 1 min, then immerse in NMD-3 developer for 30 s, rinse with deionized water and dry with nitrogen to form a pattern, then use radio frequency magnetron sputtering to deposit Ti adhesion layer and Pt electrode sequentially, wherein the power of radio frequency magnetron sputtering of Ti adhesion layer is 100 W, the time is 3 min, the thickness of Ti adhesion layer is 20 nm, the power of radio frequency magnetron sputtering of Pt electrode is 50 W, the time is 15 min, the thickness of Pt electrode is 200 nm, after Pt electrode deposition, the substrate is immersed in NMP for 1 h to remove photoresist, and a substrate containing Ti-Pt electrode is obtained. (3) On the surface of the substrate containing Ti-Pt electrode obtained in step (2), a Ti contact layer and an Nb2O5 layer are deposited sequentially by radio frequency magnetron sputtering. The power of radio frequency magnetron sputtering of the Ti contact layer is 100W, the time is 1min, and the thickness of the Ti contact layer is 10nm. The power of radio frequency magnetron sputtering of the Nb2O5 layer is 50W, the time is 45min, the distance between the Nb2O5 target and the substrate containing the electrode is 15cm, and the thickness of the Nb2O5 layer is 463nm, thus obtaining a substrate containing a sensitive layer. (4) The substrate with the sensitive layer obtained in step (3) is subjected to oxygen atmosphere heat treatment at 600℃ for 2h, with a heating rate of 5℃ / min. After the oxygen atmosphere heat treatment is completed, it is cooled to room temperature to obtain Nb2O5 nano hydrogen sensor.
[0053] Comparative Example 1 Replace the oxygen-containing atmosphere heat treatment temperature in step (4) of Example 1 with 500°C, and everything else is the same as in Example 1.
[0054] Comparative Example 2 The temperature of the oxygen-containing atmosphere heat treatment in step (4) of Example 1 is replaced with 700℃, and everything else is the same as in Example 1.
[0055] Hydrogen was detected using the hydrogen sensors prepared in Example 1 and Comparative Examples 1-2. The detection parameters were: 5-5 min (5 min air, 5 min air-hydrogen mixture), 5V, 250℃, and hydrogen concentration of 1000 ppm. The results are shown below. Figure 3 See Table 1.
[0056] In metal-oxide-semiconductor (MOS) gas sensors, the sensing response essentially originates from the change in carrier concentration on the material surface under the influence of the target gas, resulting in a measurable change in resistance. The resistance in air is typically defined as R0, and the resistance in the target gas (H2) as R0. g Sensitivity = R0 / R g .
[0057] Table 1. Sensitivity of hydrogen to hydrogen for the hydrogen sensors prepared in Example 1 and Comparative Examples 1-2.
[0058] As can be seen from Table 1, the sensitivity is highest when the heat treatment temperature in an oxygen-containing atmosphere is 600℃.
[0059] Example 2 A method for preparing an Nb2O5 nano-hydrogen sensor is as follows: (1)~(2) Same as Example 1; (3) On the surface of the substrate containing Ti-Pt electrode obtained in step (2), a Ti contact layer and an Nb2O5 layer are deposited sequentially by radio frequency magnetron sputtering. The power of the radio frequency magnetron sputtering of the Ti contact layer is 100W, the time is 1min, and the thickness of the Ti contact layer is 10nm. The power of the radio frequency magnetron sputtering of the Nb2O5 layer is 50W, the time is 30min, the distance between the Nb2O5 target and the substrate containing the electrode is 15cm, and the thickness of the Nb2O5 layer is 460nm, thus obtaining a substrate containing a sensitive layer. (4) The substrate with the sensitive layer obtained in step (3) is subjected to oxygen atmosphere heat treatment at 600℃ in air atmosphere (oxygen content 20%) for 2h, with a heating rate of 5℃ / min. After the oxygen atmosphere heat treatment is completed, it is cooled to room temperature to obtain Nb2O5 nano hydrogen sensor.
[0060] Comparative Example 3 The oxygen-containing atmosphere in step (4) of Example 2 is replaced with argon (0% oxygen content), and everything else is the same as in Example 2.
[0061] Comparative Example 4 The oxygen-containing atmosphere for heat treatment annealing in step (4) of Example 2 is replaced with a mixture of argon and oxygen (the volume ratio of oxygen to argon is 3:1, and the oxygen content is 75%), and everything else is the same as in Example 2.
[0062] Comparative Example 5 The oxygen-containing atmosphere in step (4) of Example 2 is replaced with a mixture of argon and oxygen (the volume ratio of argon to oxygen is 1:1, and the oxygen content is 50%), and everything else is the same as in Example 2.
[0063] Comparative Example 6 The oxygen-containing atmosphere in step (4) of Example 2 is replaced with oxygen (oxygen content 100%), and everything else is the same as in Example 2.
[0064] Hydrogen was detected using the hydrogen sensors prepared in Example 2 and Comparative Examples 3-6. The detection parameters were: 5-5 min (5 min air, 5 min air-hydrogen mixture), 5V, 250℃, and hydrogen concentration of 1000 ppm. The results are shown below. Figure 4 As shown in Table 2.
[0065] Table 2 shows the sensitivity of the hydrogen sensors prepared in Example 2 and Comparative Examples 3-6 to hydrogen.
[0066] As can be seen from Table 2, the hydrogen sensor prepared by heat treatment in an air atmosphere has better performance.
[0067] Example 3 A method for preparing an Nb2O5 nano-hydrogen sensor is as follows: (1)~(2) Same as Example 1; (3) On the surface of the substrate containing Ti-Pt electrode obtained in step (2), a Ti contact layer and an Nb2O5 layer are deposited sequentially by radio frequency magnetron sputtering. The power of the radio frequency magnetron sputtering of the Ti contact layer is 100W, the time is 1min, and the thickness of the Ti contact layer is 10nm. The power of the radio frequency magnetron sputtering of the Nb2O5 layer is 50W, the time is 30min, the distance between the Nb2O5 target and the substrate containing the electrode is 15cm, and the thickness of the Nb2O5 layer is 460nm, thus obtaining a substrate containing a sensitive layer. (4) The substrate with the sensitive layer obtained in step (3) is subjected to oxygen atmosphere heat treatment at 600℃ for 2h, with a heating rate of 5℃ / min. After the oxygen atmosphere heat treatment is completed, it is cooled to room temperature, and then subjected to hydrogen atmosphere heat treatment at 400℃ in a mixed gas of hydrogen and argon (the concentration of hydrogen in the mixed gas is 500ppm) for 4h, with a heating rate of 5℃ / min. After the hydrogen atmosphere heat treatment is completed, it is cooled to room temperature to obtain Nb2O5 nano hydrogen sensor.
[0068] Example 4 The time for heat treatment in the hydrogen atmosphere in step (4) of Example 3 was replaced with 2 hours, and everything else was the same as in Example 3.
[0069] Comparative Example 7 The time for heat treatment in the hydrogen atmosphere in step (4) of Example 3 was replaced with 8 hours, and everything else was the same as in Example 3.
[0070] Hydrogen sensors prepared in Examples 2, 3-4, and Comparative Example 7 were used to detect hydrogen. The detection parameters were: 5-5 min (5 min air, 5 min air-hydrogen mixture), 5V, 250℃, and a hydrogen concentration of 1000 ppm. The results are shown below. Figure 5 As shown in Table 3.
[0071] Table 3 shows the sensitivity of the hydrogen sensors prepared in Examples 2, 3-4, and Comparative Example 7 to hydrogen.
[0072] As can be seen from Table 3, the hydrogen sensor prepared by heat treatment in a hydrogen atmosphere for 4 hours has better performance.
[0073] Comparative Example 8 A method for preparing an Nb2O5 hydrogen sensor is as follows: (1)~(2) Same as Example 1; (3) On the substrate surface containing Ti-Pt electrodes obtained in step (2), a Ti contact layer and an Nb2O5 layer are deposited sequentially by radio frequency magnetron sputtering. The power of the radio frequency magnetron sputtering of the Ti contact layer is 100W, the time is 1min, and the thickness of the Ti contact layer is 10nm. The power of the radio frequency magnetron sputtering of the Nb2O5 layer is 50W, the time is 30min, the distance between the Nb2O5 target and the substrate containing the electrodes is 15cm, and the thickness of the Nb2O5 layer is 460nm, thus obtaining an Nb2O5 hydrogen sensor.
[0074] The sensitivity graphs of hydrogen sensors prepared in Examples 2, 3, and 8 to hydrogen are shown below. Figure 6 As shown (where as-deposited represents Comparative Example 8, Oxygen anealing represents Example 2, and Oxygen anealing & hydrogen annealing represents Example 3). From Figure 6 As can be seen, both oxygen-containing atmosphere heat treatment and hydrogen-containing atmosphere heat treatment improve the hydrogen sensitivity of Nb2O5 hydrogen sensor. After the two-step sintering method, the Nb2O5 porous film has high and stable sensitivity to hydrogen, and the initial response can reach an average of 2230 when measuring the common hydrogen concentration of 1000ppm.
[0075] The Nb₂O₅ nano-hydrogen sensor prepared in Example 3 was tested for selectivity to different gases at 1000 ppm as follows: Figure 7 As shown. From Figure 7As can be seen, apart from hydrogen, the sensor showed almost no response in the tests of five common test gases (CH3OH, NO2, C2H6, H2S, CO2), proving that the Nb2O5 hydrogen sensor has good gas selectivity.
[0076] The long-term stability test results of the Nb₂O₅ nano-hydrogen sensor prepared in Example 3 against 1000ppm hydrogen are as follows: Figure 8 As shown. From Figure 8 As can be seen from the data, the Nb2O5 hydrogen sensor performed well in the 130-day long-term stability test, with the hydrogen sensitivity remaining stable at around 3000.
[0077] In summary, the hydrogen sensor prepared by this invention has excellent sensitivity, selectivity, response speed and long-term stability.
[0078] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.
Claims
1. A method for preparing an Nb₂O₅ nano-hydrogen sensor, comprising the following steps: (1) An adhesion layer and an electrode are sequentially deposited on the substrate surface by photolithography patterning and radio frequency magnetron sputtering to obtain a substrate containing electrodes; (2) In step (1), a contact layer and an Nb2O5 layer are sequentially deposited on the surface of the substrate containing the electrode by radio frequency magnetron sputtering to obtain a substrate containing a sensitive layer; (3) The substrate containing the sensitive layer obtained in step (2) is subjected to oxygen-containing atmosphere heat treatment to obtain Nb2O5 nano hydrogen sensor.
2. The preparation method according to claim 1, characterized in that, The substrate in step (1) is a silicon wafer containing a silicon dioxide layer; the thickness of the silicon dioxide layer is 280~320nm.
3. The preparation method according to claim 1, characterized in that, The material of the adhesion layer in step (1) is Ti or Cr; the thickness of the adhesion layer is 10~30nm.
4. The preparation method according to claim 1, characterized in that, The electrode material in step (1) is Pt or Au; the thickness of the electrode is 100~300nm.
5. The preparation method according to claim 1, characterized in that, The thickness of the contact layer in step (2) is 5~15nm.
6. The preparation method according to claim 1, characterized in that, The thickness of the Nb2O5 layer in step (2) is 400~600nm.
7. The preparation method according to claim 1, characterized in that, The temperature of the oxygen-containing atmosphere heat treatment in step (3) is 550~650℃, and the time of the oxygen-containing atmosphere heat treatment is 1~5h.
8. The preparation method according to claim 1, characterized in that, After the oxygen-containing atmosphere heat treatment in step (3) is completed, a hydrogen-containing atmosphere heat treatment is performed; the temperature of the hydrogen-containing atmosphere heat treatment is 400~700℃, and the time of the hydrogen-containing atmosphere heat treatment is 2~5h.
9. The Nb2O5 nano-hydrogen sensor prepared by the preparation method according to any one of claims 1 to 8.
10. The application of the Nb2O5 nano-hydrogen sensor according to claim 9 in hydrogen detection.