Preparation method of a wide-bandgap oxide Schottky junction β nuclear battery unit

Abstract

The present invention belongs to the technical fields of semiconductor devices and nuclear science and technology, and particularly relates to a preparation method of a wide-bandgap oxide Schottky junction β nuclear battery unit. An n-type β-Ga2O3 textured film is grown on a substrate by a two-step hydrothermal method, and then after high-temperature annealing, it is assembled with a graphene or carbon nanotube or metal Ti / Au film top electrode to obtain a Ga2O3-based Schottky diode unit; finally, an ultra-thin 63Ni radiation source film is attached to the Ga2O3-based Schottky diode unit to obtain a wide-bandgap oxide Schottky junction β radioisotope nuclear battery. The prepared β radioisotope nuclear battery provides a reliable power source that can continuously supply power without relying on external input energy for extreme harsh environments such as deep space, deep sea, and polar regions; the energy band structure control of the wide-bandgap semiconductor is realized by doping metal elements, and the growth morphology regulation of the wide-bandgap semiconductor is realized by using a surfactant, so as to realize the growth morphology regulation and energy band structure control of the wide-bandgap semiconductor.

Description

Technical Field

[0001] The present invention belongs to the technical fields of semiconductor devices and nuclear science and technology, and particularly relates to a preparation method for a wide-bandgap oxide Schottky junction β nuclear battery unit. Background Art

[0002] Under extremely harsh environments, existing battery systems of various types of electronic device systems, such as chemical batteries, solar cells, and fuel cells, cannot adapt to harsh working conditions such as ultra-high / low temperatures, strong radiation, high vacuum, and difficult charging. Therefore, a power supply that can be maintenance-free, long-lived, and highly efficient in conversion under extreme environments has important scientific and application values for humans to move towards deep space, deep sea, and polar regions. The β-radioisotope voltaic nuclear battery is an ideal, reliable, and long-lasting micro energy source due to its long lifespan, high unit energy density, strong anti-external interference ability, stability, reliability, no need for maintenance and replacement, and easy miniaturization and integration, and has become an important development direction in the fields of MEMS and new energy.

[0003] The working principle of the β-radioisotope voltaic battery is similar to that of a solar cell, and its energy conversion device is mainly a semiconductor device (p-n junction, p-i-n junction, or Schottky diode). As Figure 4 shown, β particles are first emitted by isotopes. When β particles interact with semiconductor materials, the ionization effect of β particles generates radiation-induced electron-hole pairs. Subsequently, after the β rays generate radiation-induced electron-hole pairs, for a β-radioisotope voltaic nuclear battery based on a p-n junction or a p-i-n junction, the principle is similar to that of a photovoltaic cell. Under the action of the built-in electric field in the p-n junction, p-i-n junction, or Schottky junction, the electron-hole pairs are separated and collected by two electrodes, and converted into electrical energy. The commonly used structures in β-radioisotope voltaic nuclear batteries are p-n junction structures and Schottky structures. The built-in electric field of the p-n junction separates the electron-hole pairs, and its preparation process is relatively simple and the cost is low. With the development of semiconductor processing technology, Schottky junctions are increasingly used in isotope batteries. Compared with p-n junctions, Schottky junctions have strong radiation resistance, and the electrical output of the prepared isotope batteries is more stable.

[0004] Several key problems of β-ray voltaic batteries still cannot be effectively solved: 1) Radiation protection problem: Under the irradiation of β rays, the performance of semiconductor materials will gradually decline, but the wide-bandgap semiconductor Ga2O3 material is expected to improve this problem; 2) Doping difficulty of wide-bandgap semiconductors: As a battery energy conversion material, a semiconductor is required to have good carrier mobility. The intrinsic carrier concentration of wide-bandgap semiconductors is low, and doping is required to increase the concentration. However, during the growth process, doping and defect activation of doping elements are relatively difficult and require long-term research to overcome; 3) Difficulty in integrating and improving the output power: It has been proven that there are two effective ways to improve the performance of β-ray voltaic batteries. One is to improve the output of a single device, and the other is to perform series and parallel integration.

[0005] Compared with third-generation semiconductors, β-Ga2O3 has the advantages of a larger bandgap, a higher breakdown field strength, a larger Baliga figure of merit, a shorter absorption cut-off edge, a lower growth cost, and simple energy band engineering regulation. It is expected to become the preferred material for high-voltage, high-power, and low-loss power devices and deep ultraviolet optoelectronic devices. At the same time, as a wide-bandgap semiconductor, β-Ga2O3 has strong bonding characteristics, and the energy for its atoms to be displaced from their lattice positions is very high, so it has strong radiation resistance. There have been many studies on the doping of β-Ga2O3, and doping with various elements can be achieved. It is relatively easy to regulate the energy band structure, the number of carriers, and the carrier mobility of gallium oxide. Therefore, β-Ga2O3 has excellent prospects in the field of β-radiovoltaic nuclear batteries.

[0006] β-radiovoltaic nuclear batteries based on wide-bandgap semiconductor materials such as Ga2O3 exhibit a relatively high open-circuit voltage, a relatively high energy conversion efficiency, and strong radiation resistance, and thus have attracted much attention from researchers. On the other hand, in order to obtain high-power nuclear battery devices, compared with optimizing the transducer material and device structure design to further improve the performance of a single device, series-parallel integration of devices is a more efficient and feasible method at present. However, in the existing device preparation and integration methods, the volume of a single device cannot be further reduced, and the transducer material cannot be stably prepared, resulting in a low integration density and an inability to substantially increase the output power. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a preparation method for a wide-bandgap oxide Schottky junction β nuclear battery unit in view of the problems existing in the prior art.

[0008] The following technical solutions are adopted to solve the technical problems of the present invention:

[0009] A preparation method for a wide-bandgap oxide Schottky junction β nuclear battery unit, the specific process being: first, grow an n-type β-Ga2O3 textured film on a substrate by a two-step hydrothermal method, and then assemble it with a graphene or carbon nanotube or metal Ti / Au film top electrode after high-temperature annealing to obtain a Ga2O3-based Schottky diode unit; finally, attach an ultra-thin 63Ni radiation source film to the Ga2O3-based Schottky diode unit to obtain a wide-bandgap oxide Schottky junction β-radiovoltaic nuclear battery.

[0010] The steps of the above preparation method for a wide-bandgap oxide Schottky junction β-radiovoltaic nuclear battery are as follows:

[0011] Step a: hydrothermally growing an n-type Ga2O3 textured film on an FTO substrate using gallium nitrate as a gallium source via a two-step process. In the first step, a mixed solution of ethanol and deionized water is used as a solvent to grow a Ga2O3 seed layer. In the second step, an aqueous solution is used to grow a Ga2O3 textured film. After the two-step hydrothermal growth, a high-temperature annealing step is performed to obtain an n-type β-Ga2O3 textured film.

[0012] Step b, on the surface of the n-type β-Ga2O3 textured film, a graphene top electrode is covered by floating transfer, a metal Ni / Au film top electrode is deposited by electron beam thermal evaporation, or a carbon nanotube film top electrode is constructed by LB film method to obtain a Ga2O3-based Schottky diode unit;

[0013] Step c: The obtained Ga2O3-based Schottky diode unit is attached to the self-supporting ultra-thin 63Ni radiation source film prepared by electroplating through floating transfer. After the attachment is completed, the sample is naturally dried and baked. After the baking is completed, the sample is removed and naturally cooled to room temperature to obtain a wide bandgap oxide Schottky junction β-radiation voltaic nuclear battery.

[0014] The preparation method of the wide bandgap oxide Schottky junction beta-radiation voltaic nuclear battery comprises the following specific steps:

[0015] Step a: growing an n-type β-Ga2O3 textured thin film on a FTO substrate by a hydrothermal method:

[0016] (1) Use acetone, ethanol, and deionized water to clean the FTO substrate in sequence, and dry it after cleaning;

[0017] (2) Fully mix ethanol and deionized water in a volume ratio of 1:1, then add Ga2(NO3)6·nH2O and stir thoroughly to form a Ga2(NO3)6·nH2O ethanol aqueous solution with a concentration of 1 mol / L;

[0018] (3) Place the cleaned FTO substrate in a 10ml reactor at an angle, and add 8ml of Ga2(NO3)6·nH2O ethanol aqueous solution into the reactor, with the FTO surface facing downwards;

[0019] (4) The reaction kettle was sealed and reacted at 90-100°C for 1-2 hours. After the reaction was completed, the solution in the reactor was removed after the reaction was naturally cooled to room temperature;

[0020] (5) Add Ga2(NO3)6·nH2O to deionized water and stir well to dissolve, forming an aqueous solution of Ga2(NO3)6·nH2O with a concentration of 1 mol / L. Add 8 ml of it to the reaction kettle in step (4). Under closed conditions, the reaction kettle reacts at 140 - 170 °C for 24 - 36 h. After the reaction, it is naturally cooled to room temperature to obtain an FTO substrate with a Ga2O3 textured film grown on it.

[0021] (6) Place the FTO substrate with the Ga2O3 textured film grown on it in a high-temperature furnace and anneal it at 550 - 850 °C for 12 - 18 h to obtain a structurally dense n-type β-Ga2O3 textured film on the FTO substrate.

[0022] Step b: Assemble the β-Ga2O3 textured film and the graphene top electrode to obtain a Ga2O3-based Schottky diode unit.

[0023] (1) Use the CVD method to grow single-crystal graphene on the surface of a Cu foil, then cover the graphene with a PMMA film, and then place it in a 3 mol / L ferric chloride FeCl3 solution for etching for 30 - 60 min to completely remove the Cu, so that the PMMA-protected graphene film floats on the surface of the solution for use.

[0024] (2) Gently drag out the PMMA-protected graphene film with the FTO substrate of the β-Ga2O3 textured film and move it to deionized water to keep it floating. Soak it for 30 - 60 min to completely remove the ferric chloride, and then dry it at 40 - 100 °C for 2 - 4 h under vacuum conditions to make the graphene film tightly adhere to the β-Ga2O3 textured film, obtaining a Ga2O3-based Schottky diode unit.

[0025] Step c: Attach a self-supporting ultra-thin 63Ni radiation source film with a thickness of 20 - 23 μm prepared by electroplating. After the attachment, dry the sample in a vacuum oven at 40 - 100 °C for 2 - 4 h, and then take down the sample and naturally cool it to room temperature to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery.

[0026] The said step b is as follows:

[0027] (1) Wash the FTO substrate with an n-type β-Ga2O3 textured film successively with ethanol and deionized water, and then dry it with a nitrogen gun for use.

[0028] (2) Disperse 0.05 g of carbon nanotube powder in a mixed solution of 10 ml of chloroform and dimethylformamide DMF, where the volume ratio of chloroform to dimethylformamide DMF is 1:1.

[0029] (3) Inject distilled water into the puller until it reaches the horizontal level of the puller. Use a 1000 μl syringe to aspirate 500 μl of the solution prepared in step (2) and disperse it drop by drop into the distilled water.

[0030] (4) Immerse the FTO substrate with the n-type β-Ga2O3 textured film into the solution in step (3) by the Langmuir-Blodgett method, and slowly pull it out at a speed of 0.5 - 2 cm / min under a surface film pressure of 30 - 35 Pa to obtain Ga2O3-based Schottky diode units.

[0031] Step b is as follows:

[0032] (1) Clean and dry the FTO substrate with the n-type β-Ga2O3 textured film, and place it on the carrier plate.

[0033] (2) Open the thermal evaporation chamber, place the carrier plate into the chamber and attach it to the upper evaporation area. Put Ni particles and Au particles into two heating crucibles of the thermal evaporator respectively, and then close the evaporation chamber.

[0034] (3) Evaporate under the condition that the vacuum degree is 1×10 -4 -5×10 -4 Pa. First, evaporate Ni as the first layer with a current of 70 - 80 A and deposit 50 nm of Ni as the adhesion layer. Then, deposit 150 nm of Au as the electrode layer on the Ni layer with a current between 50 - 60 A. After the temperature cools down, take out the Ga2O3-based Schottky diode unit with Ni / Au electrodes.

[0035] The method for growing single-crystal graphene by the CVD method is as follows:

[0036] (1) Copper foil preparation: Put two copper foils with a thickness of 20 - 25 μm into acetone, alcohol, and deionized water for cleaning respectively, and then blow dry the surfaces of the copper foils with high-purity nitrogen. After drying, place them in a CVD tube furnace and heat them up to 1000 - 1050 °C. First, introduce H2 for cleaning for 1 - 1.2 h, and then introduce CH4 for cleaning for 1 - 1.2 h.

[0037] (2) Copper foil annealing: Anneal the copper foil at 1000 - 1050 °C for 30 - 90 min in an H2 atmosphere.

[0038] (3) Introduce carbon source: At a temperature of 1000 - 1050 °C, introduce a mixed gas of H2 and CH4 with a volume ratio of 99:1 and keep it for 10 - 20 min.

[0039] (4) Cooling: Continuously introduce a mixed gas of H2 and CH4 with a volume ratio of 99:1. When the temperature drops to 250 - 300 °C, directly open the furnace body. When the furnace temperature rapidly drops below 40 °C, take out the copper foil with graphene attached.

[0040] (5) Coating: Take out the copper foil with graphene attached and place it on a spin coater. Drop 200 μl of a polymethyl methacrylate (PMMA) solution with a mass concentration of 5.5%. First, run at 500 - 800 rmp for 10 - 30 seconds, and then run at a high speed of 3000 - 5000 rmp for 20 - 40 seconds to form a graphene covered with a PMMA thin film by spin coating.

[0041] In the second step of step a when growing the Ga2O3 textured film using an aqueous solution, metal salts of metal elements Ni, Sn, Al, and Mn are added to achieve doping modification.

[0042] In the second step of step a when growing the Ga2O3 textured film using an aqueous solution, a surfactant such as cetyltrimethylammonium bromide or sodium dodecyl sulfate is used to regulate the surface growth state of gallium oxide, and a Ga2O3 textured film with a denser surface state is obtained.

[0043] The specific method for obtaining the self - supported 63Ni radiation source thin film using electroplating in step c is as follows:

[0044] (1) Dissolve 210 g of NiSO4·6H2O, 55 g of NiCl2·6H2O, 65 g of NaCl, and 30 g of H3BO3 in 1 L of deionized water, and adjust the pH value to 4 - 5.

[0045] (2) Pour the solution in (1) into an electroplating bath, and place the electroplating bath in a water bath at 25 - 30 °C for 30 - 60 minutes.

[0046] (3) Place a 5 cm x 6 cm ITO glass into the electroplating bath and fix it vertically.

[0047] (4) Place a 5 cm x 6 cm nickel sheet into the electroplating bath and fix it vertically parallel to the ITO in (3) with a distance of 8 - 10 cm.

[0048] (5) Connect the negative electrode of the electrochemical workstation to the ITO glass, and connect the reference electrode and the counter electrode of the electrochemical workstation to the nickel sheet.

[0049] (6) Adopt the constant - current electroplating method, set the initial voltage to 1.5 V, the output current to 100 mA, and the electroplating time to 40 - 45 minutes to obtain a nickel thin film grown on the surface of the ITO.

[0050] (7) Take out the ITO glass with the nickel thin film in (6), attach a transparent tape with a width of 5 cm, stick the nickel thin film on the tape, and then tear off the tape to obtain a transparent tape with a nickel thin film;

[0051] (8) Flatten the transparent tape with the nickel thin film and gently place it on the surface of the acetone liquid to dissolve the adhesive in the transparent tape to obtain a self-supporting nickel thin film;

[0052] (9) Transfer the nickel thin film in (8) to deionized water and wash it 3 - 5 times.

[0053] The present invention uses a two-step hydrothermal growth technique to form a dense n-type β-Ga2O3 textured film on a substrate, and then assembles it with different types of graphene carbon nanotubes or metal Ti / Au film top electrodes to obtain a Ga2O3-based Schottky diode unit; finally, an ultra-thin 63Ni radiation source is attached to the Ga2O3-based Schottky diode unit to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery, which effectively integrates technologies such as Ga2O3 Schottky diode preparation, wafer-level micron 63Ni radiation source preparation, and floating transfer stacking. The prepared β-radiation voltaic nuclear battery provides a reliable power source that can continuously supply power without relying on external input energy for extreme harsh environments such as deep space, deep sea, and polar regions; the energy band structure of the wide-bandgap semiconductor is controlled by doping metal elements, and the growth morphology of the wide-bandgap semiconductor is regulated by using a surfactant to achieve the growth morphology regulation and energy band structure control of the wide-bandgap semiconductor; the preparation of a self-supporting single device of the β-radiation voltaic battery is realized, and a higher open-circuit voltage of the device is achieved and long-term energy output is realized. Description of the Drawings

[0054] Figure 1 It is the SEM image of the n-type β-Ga2O3 textured film in Example 1 of the present invention on an FTO substrate;

[0055] Figure 2 It is the SEM image of the doped Sn n-type β-Ga2O3 textured film in Example 3 of the present invention on an FTO substrate;

[0056] Figure 3 It is the SEM image of the n-type β-Ga2O3 textured film using cetyltrimethylammonium bromide as a surfactant in Example 2 of the present invention on an FTO substrate;

[0057] Figure 4 It is the schematic diagram of the preparation of the Ga2O3-based Schottky diode unit in Example 3 of the present invention. Detailed Description of the Invention

[0058] Example 1

[0059] A method for preparing a wide-bandgap oxide Schottky junction β-nuclear battery cell comprises the following steps: growing an n-type Ga2O3 textured film on an FTO substrate by a hydrothermal method; directly using the FTO substrate as a bottom electrode after high-temperature annealing; removing the Cu substrate from a CVD-grown graphene covered with a PMMA film using an FeCl3 solution to obtain a self-supporting graphene film; then pulling the film out and placing it in deionized water to keep it floating; using the prepared Ga2O3 film to scoop up the graphene film in the deionized water to assemble a Ga2O3 Schottky diode device unit; then floatingly transferring an ultra-thin 63Ni film prepared by electroplating to the Ga2O3 Schottky diode device unit; and finally drying the film to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery. The specific steps are as follows:

[0060] Step a: Growth of Ga2O3 textured film on FTO substrate using high temperature hydrothermal method

[0061] (1) Cut the FTO substrate into 2×1cm 2 Use acetone, ethanol and deionized water to clean the size in sequence, and dry it after cleaning;

[0062] (2) Thoroughly mix 5 ml of ethanol and 5 ml of deionized water, then weigh 0.2564 g of Ga2(NO3)6·nH2O at a concentration of 1 mol / L and add it to the beaker and stir thoroughly to obtain a gallium nitrate ethanol aqueous solution;

[0063] (3) Tilt the cleaned FTO substrate 60° and place it in a 10ml reactor liner with the FTO side facing down. Pour 8ml of gallium nitrate ethanol aqueous solution into the reactor liner and tighten the reactor.

[0064] (4) React at 100 °C for 1 h, and then cool naturally to room temperature after the reaction is completed;

[0065] (5) Open the reactor after the reaction in (4) is completed and cooled, and the solution in the reactor liner is sucked out to remove the reacted solution;

[0066] (6) Take 10 ml of deionized water, weigh 0.2564 g of Ga2(NO3)6·nH2O according to the concentration of 1 mol / L, stir and dissolve it thoroughly to obtain a Ga2(NO3)6·nH2O aqueous solution with a concentration of 1 mol / L;

[0067] (7) Pour 8 ml of the gallium nitrate aqueous solution prepared in step (6) into the inner container of the reactor, tighten the reactor, and then react the sealed reactor at 150°C for 24 hours. After the reaction is completed, cool it down naturally to room temperature.

[0068] (8) Take out the FTO substrate with the grown Ga2O3 textured film, and clean it 3 times with ethanol and ultrasonic waves to remove the surface attachments.

[0069] (9) Put the FTO substrate taken out in (8) into a high-temperature tube furnace and anneal it at 550 °C for 18 h to obtain a structurally dense n-type β-Ga2O3 textured film on the FTO substrate.

[0070] Step b: Assemble the β-Ga2O3 textured film and the graphene top electrode to obtain the Ga2O3-based Schottky diode unit

[0071] (1) Grow single-crystal graphene with an area of 2×2 cm on the surface of a Cu foil by the CVD method. The method for growing single-crystal graphene by the CVD method is as follows: 2 1. Preparation of the copper foil: Put two 20-μm-thick copper foils (2 cm x 2 cm) into acetone, alcohol, and deionized water and clean them 2 times respectively. Then blow dry the surface of the copper foils with high-purity nitrogen. After drying, place them separately in the center of the heating zone of the CVD tube furnace, and set the CVD tube furnace to heat up to 1050 °C at a heating rate of 5 °C / min. After closing the tube furnace, first introduce H2 for cleaning for 1 h, and then introduce CH4 for cleaning for 1 h.

[0072] 2. Annealing of the copper foil: Close the CH4 in step 1, and anneal the copper foil at 1050 °C for 30 min in an H2 atmosphere to remove the oxides on the surface of the copper foil, thereby obtaining a copper foil with a relatively single surface crystal orientation and strong catalytic activity.

[0073] 3. Introduction of the carbon source: Open the CH4 and H2 channels, and introduce a mixed gas of H2 and CH4 with a volume ratio of 99:1 at a temperature of 1050 °C and keep it for 10 min.

[0074] 4. Cooling: Continuously introduce a mixed gas of H2 and CH4 with a volume ratio of 99:1. When the temperature drops to 300 °C, directly open the furnace body. When the furnace temperature quickly drops below 40 °C, close the vacuum and gas supply systems, and take out the copper foil with graphene attached.

[0075] 5. Coating: Place the taken-out copper foil with graphene on a spin coater. After vacuum suction, drop 200 μl of a 5.5% mass concentration of poly(methyl methacrylate) (PMMA) solution, run at a low speed of 500 rmp for 10 seconds and at a high speed of 3000 rmp for 20 seconds to spin-coat graphene covered with a PMMA film.

[0076] 5. Coating: Place the taken-out copper foil with graphene on a spin coater. After vacuum suction, drop 200 μl of a 5.5% mass concentration of poly(methyl methacrylate) (PMMA) solution, run at a low speed of 500 rmp for 10 seconds and at a high speed of 3000 rmp for 20 seconds to spin-coat graphene covered with a PMMA film.

[0077] 6. Etching: The graphene covered with the PMMA film is then placed in a 3 mol / LFeCl3 solution to float on the surface of the solution. Etching is performed for 30 minutes to completely remove the Cu, thus forming a self-supporting floating graphene film for future use.

[0078] (2) Use the FTO substrate with β-Ga2O3 textured film to gently drag the PMMA / graphene film out and move it to deionized water to keep it floating. Soak it for 30 minutes to remove the ferric chloride. Then gently drag it out of the deionized water and dry it at 100℃ under vacuum for 2 hours to make the graphene film tightly attached to the Ga2O3 textured film. Then, a Ga2O3-based Schottky diode unit can be obtained.

[0079] Step c, attaching an ultra-thin 63Ni radiation source to obtain a wide bandgap oxide Schottky junction β-radiation voltaic nuclear battery;

[0080] (1) A self-supporting 63Ni radiation source film is obtained by electroplating. The specific method is as follows:

[0081] 1. Dissolve 210g NiSO4·6H2O, 55g NiCl2·6H2O, 65g NaCl, and 30g H3BO3 in 1L deionized water and adjust the pH to 4.

[0082] 2. Pour the solution in step 1 into the electroplating tank, and place the electroplating tank in a 30°C water bath for 30 minutes;

[0083] 3. Place the ITO glass of 5cmx6cm in the electroplating tank and fix it vertically;

[0084] 4. Place a 5cmx6cm nickel sheet into the electroplating tank and place it parallel to the ITO sheet 3 at a distance of 10cm and fix it vertically.

[0085] 5. Connect the negative electrode of the electrochemical workstation to the ITO glass, and connect the reference electrode and counter electrode of the electrochemical workstation to the nickel sheet;

[0086] 6. Using constant current electroplating method, set the initial voltage to 1.5V, the output current to 100mA, and the electroplating time to 40min to obtain a nickel film grown on the ITO surface;

[0087] 7. Take out the ITO glass with nickel film in step 6, attach it with a 5 cm wide transparent tape, stick the nickel film on the tape, and then tear off the tape to obtain a transparent tape with nickel film, wherein the transparent tape film component is BOPP and the glue component is acrylic glue;

[0088] 8. Flatten the transparent tape with a nickel thin film and gently place it on the surface of acetone liquid to dissolve the adhesive in the transparent tape, obtaining a self-supporting ultra-thin 63Ni film with a thickness of 20 μm;

[0089] 9. Transfer the ultra-thin 63Ni film in step 8 to deionized water and wash it three times;

[0090] (2). Make one end of the ultra-thin 63Ni film contact with a Ga2O3-based Schottky diode unit, then gently pull out the Ga2O3-based film to make the two fully adhere to avoid generating air bubbles in the middle. After the adhesion is completed, let the sample dry naturally and bake it at 40 °C under vacuum for 4 hours to make the 63Ni film tightly adhere to the Ga2O3-based diode film. After the baking is completed, remove the sample and let it cool naturally to room temperature to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery.

[0091] Example 2

[0092] A preparation method of a wide-bandgap oxide Schottky junction β-nuclear battery unit. Use the hydrothermal method to grow an n-type Ga2O3 textured film on an FTO substrate, and use cetyltrimethylammonium bromide as a surfactant to obtain a denser textured film. Directly use the FTO substrate as the bottom electrode for high-temperature annealing. After removing the Cu substrate from the graphene covered with a PMMA film grown by CVD using an FeCl3 solution, obtain a self-supporting graphene film, then drag it out and move it to deionized water to keep it floating. Scoop up the graphene film in the deionized water with the prepared Ga2O3 film to assemble a Ga2O3 Schottky diode device unit. Subsequently, float and transfer the electroplated ultra-thin 63Ni film onto the Ga2O3 Schottky diode device unit, and dry it to finally obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery. The specific steps are as follows:

[0093] Step a: Use the high-temperature hydrothermal method to grow a Ga2O3 textured film on an FTO substrate

[0094] (1). Cut the FTO substrate into a size of 2×1 cm 2 and wash it successively with acetone, ethanol, and deionized water. After the washing is completed, dry it for standby;

[0095] (2). Thoroughly mix 5 ml of ethanol and 5 ml of deionized water, then weigh 0.2564 g of Ga2(NO3)6·nH2O according to a concentration of 1 mol / l and add it to a beaker and stir well to obtain a gallium nitrate ethanol aqueous solution;

[0096] (3). Place the cleaned FTO substrate at an angle of 70° into the inner liner of a 10 ml reaction kettle, with the FTO side facing down. Pour 8 ml of the gallium nitrate ethanol aqueous solution into the inner liner of the reaction kettle and tighten the reaction kettle;

[0097] (4) React at 90 °C for 2 h, and after the reaction is completed, naturally cool down to room temperature;

[0098] (5) Open the reactor after the reaction in (4) is completed and cooled, and suck out the solution in the inner liner of the reactor to remove the solution after the reaction;

[0099] (6) Measure 10 ml of deionized water, add 0.2564 g of Ga2(NO3)6·nH2O weighed according to a concentration of 1 mol / L and 0.0366 g of cetyltrimethylammonium bromide weighed according to a concentration of 0.1 mol / L, and stir well to dissolve to obtain an aqueous solution of Ga2(NO3)6·nH2O with a concentration of 1 mol / L. The surfactant realizes the regulation of the dense state on the surface of the gallium oxide texture film;

[0100] (7) Pour 8 ml of the gallium nitrate aqueous solution in step (6) into the inner liner of the reactor, tighten the reactor, and then react the sealed reactor at 140 °C for 24 h. After the reaction is completed, naturally cool down to room temperature;

[0101] (8) Take out the FTO substrate with the Ga2O3 texture film grown on it, and use ethanol combined with ultrasonic cleaning 4 times to remove the surface attachments;

[0102] (9) Put the FTO substrate taken out in (8) into a high-temperature tube furnace and anneal it at 850 °C for 12 h to obtain a structurally dense n-type β-Ga2O3 texture film on the FTO substrate;

[0103] Step b: Assemble the β-Ga2O3 texture film and the graphene top electrode to obtain a Ga2O3-based Schottky diode unit

[0104] (1) Grow single-crystal graphene with a size of 2×2 cm on the surface of a Cu foil by the CVD method. The method for growing single-crystal graphene by the CVD method is as follows: 2 The method for growing single-crystal graphene by the CVD method is as follows:

[0105] 1. Copper foil preparation: Put two copper foils with a thickness of 20 μm (2 cm x 2 cm) into acetone, alcohol, and deionized water respectively and wash them 5 times. After that, blow dry the surface of the copper foil with high-purity nitrogen. After drying, place them separately in the center of the heating zone of the CVD tube furnace. Set the CVD tube furnace to heat up to 1000 °C at a heating rate of 6 °C / min, then seal the tube furnace. First, introduce H2 for cleaning for 1.2 h, and then introduce CH4 for cleaning for 1.2 h;

[0106] 2. Copper foil annealing: Close CH4 in 1, and anneal the copper foil at 1000 °C for 90 min in an H2 atmosphere to remove the oxides on the surface of the copper foil, so as to obtain a copper foil with a relatively single surface crystal orientation and strong catalytic activity;

[0107] 3. Introduce carbon source: Open the CH4 and H2 channels. Under the temperature condition of 1000 °C, introduce a mixed gas of H2 and CH4 with a volume ratio of 99:1 and keep it for 20 min.

[0108] 4. Cool down: Continuously introduce the mixed gas of H2 and CH4 with a volume ratio of 99:1. When the temperature drops to 250 °C, directly open the furnace body. When the furnace temperature rapidly drops below 40 °C, turn off the vacuum and gas supply systems, and take out the copper foil with graphene attached.

[0109] 5. Coating: Place the taken-out copper foil with graphene on a spin coater. After vacuum suction, drop 200 μl of a polymethyl methacrylate (PMMA) solution with a mass concentration of 5.5%. Run at a low speed of 800 rmp for 30 seconds and at a high speed of 5000 rmp for 40 seconds to form graphene covered with a PMMA film by spin coating.

[0110] 6. Etching: Then place the graphene covered with the PMMA film into a 3 mol / L FeCl3 solution so that it floats on the surface of the solution. Etch for 60 min to completely remove Cu, and prepare the graphene into a self-supporting film for floating and standby.

[0111] (2) Gently drag out the PMMA / graphene film with the FTO substrate with a β-Ga2O3 textured film and move it to deionized water to keep it floating. Immerse it for 60 min to remove ferric chloride. Then gently drag it out of the deionized water and dry it at 40 °C for 4 hours in a vacuum state to make the graphene film tightly adhere to the Ga2O3 textured film, and then a Ga2O3-based Schottky diode unit can be obtained.

[0112] Step c. Attach an ultra-thin 63Ni radiation source to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery;

[0113] (1). Obtain a self-supporting 63Ni radiation source film using electroplating method;

[0114] 1. Dissolve 210 g of NiSO4·6H2O, 55 g of NiCl2·6H2O, 65 g of NaCl, and 30 g of H3BO3 into 1 L of deionized water and adjust the pH value to 5.

[0115] 2. Pour the solution in 1 into an electroplating bath and place the electroplating bath in a water bath at 25 °C for 60 min.

[0116] 3. Place ITO glass with a size of 5 cm x 6 cm into the electroplating bath and fix it vertically.

[0117] 4. Place a nickel sheet with a size of 5 cm x 6 cm into the electroplating bath and place it parallel to the ITO in 3 with a distance of 8 cm and fix it vertically.

[0118] 5. Connect the negative electrode of the electrochemical workstation to the ITO glass, and connect the reference electrode and counter electrode of the electrochemical workstation to the nickel sheet;

[0119] 6. Adopt the constant current electroplating method, set the initial voltage to 1.5 V, the output current to 100 mA, and the electroplating time to 45 min to obtain a nickel thin film grown on the surface of ITO;

[0120] 7. Take out the ITO glass with the nickel thin film in step 6, attach a transparent tape with a width of 5 cm, stick the nickel thin film on the tape, and then tear off the tape to obtain a transparent tape with a nickel thin film, where the transparent tape film is made of BOPP and the glue is made of acrylate glue;

[0121] 8. Flatten the transparent tape with the nickel thin film and gently place it on the surface of the acetone liquid to dissolve the adhesive in the transparent tape to obtain a self-supporting ultra-thin 63Ni film with a thickness of 23 μm;

[0122] 9. Transfer the ultra-thin 63Ni film in step 8 to deionized water and wash it 5 times;

[0123] (2). Make one end of the ultra-thin 63Ni film contact with the Ga2O3-based Schottky diode unit, then gently pull out the Ga2O3-based film to make the two fully adhere to avoid generating bubbles in the middle. After the adhesion is completed, let the sample dry naturally and bake it at 100 °C in a vacuum state for 2 hours to make the 63Ni film and the Ga2O3-based diode film adhere tightly. After the baking is completed, take down the sample and let it cool naturally to room temperature to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery.

[0124] Example 3

[0125] A preparation method of a wide-bandgap oxide Schottky junction β nuclear battery unit, using a Sn-containing metal salt for hydrothermal doping, growing an n-type Ga2O3 textured film on an FTO substrate by the hydrothermal method, directly using the FTO substrate as the bottom electrode after high-temperature annealing, obtaining a self-supporting graphene film by removing the Cu substrate from the graphene covered with a PMMA film grown by CVD using an FeCl3 solution, then dragging it out and moving it to deionized water to keep it floating, fishing up the graphene film in the deionized water with the prepared Ga2O3 film to assemble a Ga2O3 Schottky diode device unit, and then floating and transferring the ultra-thin 63Ni film prepared by electroplating onto the Ga2O3 Schottky diode device unit, and drying to finally obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery. The specific steps are as follows:

[0126] Step a: Grow a Ga2O3 textured film on an FTO substrate by the high-temperature hydrothermal method

[0127] (1). Cut the FTO substrate into 2×2 cm 2 in size, and clean it successively with acetone, ethanol, and deionized water. After cleaning, dry it for standby;

[0128] (2). Thoroughly mix 5 ml of ethanol and 5 ml of deionized water in a beaker. Then, weigh 0.2564 g of Ga2(NO3)6·nH2O at a concentration of 1 mol / L and weigh 0.0185 g of SnCl2·4H2O, and add them to the beaker and stir well to obtain an aqueous solution of gallium nitrate in ethanol;

[0129] (3). Place the cleaned FTO substrate at an angle of 50° into the inner liner of a 10-ml reaction kettle, with the FTO side facing down. Pour 8 ml of the aqueous solution of gallium nitrate in ethanol into the inner liner of the reaction kettle and tighten the reaction kettle;

[0130] (4). React at 100 °C for 1 h. After the reaction is completed, allow it to cool naturally to room temperature;

[0131] (5). Open the reaction kettle that has completed the reaction and cooled in (4), and suck out the solution in the inner liner of the reaction kettle to remove the solution after the reaction;

[0132] (6). Measure 10 ml of deionized water, weigh 0.2564 g of Ga2(NO3)6·nH2O at a concentration of 1 mol / L, and stir well to dissolve it to obtain an aqueous solution of Ga2(NO3)6·nH2O with a concentration of 1 mol / L;

[0133] (7). Pour 8 ml of the aqueous solution of gallium nitrate in step (6) into the inner liner of the reaction kettle, tighten the reaction kettle, and then react the sealed reaction kettle at 150 °C for 24 h. After the reaction is completed, allow it to cool naturally to room temperature;

[0134] (8). Take out the FTO substrate with the Ga2O3 textured film grown on it, and clean it 5 times with ethanol using ultrasonic waves to remove the surface attachments;

[0135] (9). Place the FTO substrate taken out in (9) into a high-temperature tube furnace and anneal it at 850 °C for 12 h to obtain a structurally dense n-type β-Ga2O3 textured film on the FTO substrate.

[0136] Step b: Assemble the β-Ga2O3 textured film and the graphene top electrode to obtain a Ga2O3-based Schottky diode unit

[0137] (1). Grow single-crystal graphene with a size of 2×2 cm on the surface of a Cu foil by the CVD method. The method for growing single-crystal graphene by the CVD method is as follows: 2 The method for growing single-crystal graphene by the CVD method is as follows:

[0138] 1. Copper foil preparation: Two copper foils with a thickness of 20 μm (2 cm x 2 cm) are separately placed in acetone, alcohol, and deionized water for cleaning twice. After that, the surfaces of the copper foils are dried with high-purity nitrogen. After drying, they are respectively placed in the center of the heating zone of the furnace tube of the CVD tube furnace. The CVD tube furnace is set to heat up to 1015 °C at a heating rate of 5 °C / min, and then the tube furnace is sealed. First, H2 is introduced for cleaning for 1.2 h, and then CH4 is introduced for cleaning for 1.2 h;

[0139] 2. Copper foil annealing: Close CH4 in step 1. Under the H2 atmosphere, the copper foil is annealed at 1015 °C for 30 min to remove the oxides on the surface of the copper foil, thereby obtaining a copper foil with a relatively single surface crystal orientation and strong catalytic activity;

[0140] 3. Introduce carbon source: Open the CH4 and H2 channels. Under the temperature condition of 1015 °C, a mixed gas of H2 and CH4 with a volume ratio of 99:1 is introduced and maintained for 20 min;

[0141] 4. Cooling: Continuously introduce a mixed gas of H2 and CH4 with a volume ratio of 99:1. When the temperature drops to 300 °C, directly open the furnace body. When the furnace temperature rapidly drops below 40 °C, turn off the vacuum and gas supply systems, and take out the copper foil with graphene attached;

[0142] 5. Coating: Place the taken-out copper foil with graphene on a spin coater. After vacuum suction, 200 μl of a PMMA solution with a mass concentration of 5.5% is dropped, and it runs at a low speed of 500 rmp for 10 seconds and at a high speed of 3000 rmp for 20 seconds to form graphene covered with a PMMA thin film by spin coating;

[0143] 6. Etching: The graphene covered with the PMMA thin film is then placed in a 3 mol / L FeCl3 solution of ferric chloride to make it float on the surface of the solution. It is etched for 30 min to completely remove Cu, and the graphene is prepared into a self-supporting thin film and floated for use;

[0144] (2) Gently drag out the PMMA / graphene film with the β-Ga2O3 textured film FTO substrate and move it to deionized water to keep it floating. Immerse it for 60 min to remove ferric chloride. Then gently drag out the deionized water and dry it at 80 °C for 3 hours in a vacuum state to make the graphene thin film tightly adhere to the Ga2O3 textured film, and the Ga2O3-based Schottky diode unit can be obtained.

[0145] Step c: Attach an ultra-thin 63Ni radiation source to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery;

[0146] (1). A self-supporting 63Ni radiation source thin film obtained by electroplating;

[0147] 1. Dissolve 210 g of NiSO4·6H2O, 55 g of NiCl2·6H2O, 65 g of NaCl, and 30 g of H3BO3 in 1 L of deionized water, and adjust the pH value to 4;

[0148] 2. Pour the solution in step 1 into an electroplating bath, and place the electroplating bath in a water bath at 25 °C for 30 min;

[0149] 3. Place an ITO glass with a size of 5 cm x 6 cm into the electroplating bath and fix it vertically;

[0150] 4. Place a nickel sheet with a size of 5 cm x 6 cm into the electroplating bath and place it parallel to the ITO in step 3 at a distance of 8 cm and fix it vertically;

[0151] The negative electrode of the electrochemical workstation is connected to the ITO glass, and the reference electrode and counter electrode of the electrochemical workstation are connected to the nickel sheet;

[0152] 6. Adopt the constant current electroplating method, set the initial voltage to 1.5 V, the output current to 100 mA, and the electroplating time to 40 min to obtain a nickel thin film grown on the surface of the ITO;

[0153] 7. Take out the ITO glass with the nickel thin film in step 6, attach a transparent tape with a width of 5 cm, stick the nickel thin film on the tape, and then tear off the tape to obtain a transparent tape with a nickel thin film, where the transparent tape film is made of BOPP and the glue is made of acrylate glue;

[0154] 8. Flatten the transparent tape with the nickel thin film and gently place it on the surface of the acetone liquid to dissolve the adhesive in the transparent tape to obtain a self-supporting ultra-thin 63Ni film with a thickness of 23 μm;

[0155] 9. Transfer the ultra-thin 63Ni film in step 8 to deionized water and wash it 5 times;

[0156] (2). Make one end of the ultra-thin 63Ni film contact with the Ga2O3-based Schottky diode unit, and then gently pull out the Ga2O3-based film to make the two completely adhere to each other to avoid air bubbles in the middle. After the adhesion is completed, let the sample dry naturally and bake it at 100 °C in a vacuum state for 2 hours to make the 63Ni film and the Ga2O3-based diode film adhere tightly. After the baking is completed, take down the sample and let it cool naturally to room temperature to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery.

[0157] Example 4

[0158] A method for preparing a wide-bandgap oxide Schottky junction β-nuclear battery cell comprises growing an n-type Ga2O3 textured film on an FTO substrate by a hydrothermal method, directly using the FTO substrate as a bottom electrode, self-assembling carbon nanotubes on a deionized water surface by an LB film method to obtain a self-supporting carbon nanotube film, using the prepared Ga2O3 film to scoop up the carbon nanotube film in the deionized water to assemble a Ga2O3 Schottky diode device unit, then floatingly transferring an ultra-thin 63Ni film prepared by electroplating onto the Ga2O3 Schottky diode device unit, and drying to finally obtain a wide-bandgap oxide Schottky junction β-radiovoltaic nuclear battery. The specific steps are as follows:

[0159] Step a: Growth of Ga2O3 textured film on FTO substrate using high temperature hydrothermal method

[0160] (1) Cut the FTO substrate into 2×1cm 2 Use acetone, ethanol and deionized water to clean the size in sequence, and dry it after cleaning;

[0161] (2) Mix 5 ml of ethanol and 5 ml of deionized water in a beaker, then weigh 0.2564 g of Ga2(NO3)6·nH2O at a concentration of 1 mol / L and add it to the beaker and stir thoroughly to obtain a gallium nitrate ethanol aqueous solution;

[0162] (3) Tilt the cleaned FTO substrate 70° and place it in a 10ml reactor liner with the FTO side facing down. Pour gallium nitrate ethanol aqueous solution into the reactor liner and tighten the reactor.

[0163] (4) React at 90 °C for 2 h, and then cool naturally to room temperature after the reaction is completed;

[0164] (5) Open the reactor after the reaction in (4) is completed and cooled, and the solution in the reactor liner is sucked out to remove the reacted solution;

[0165] (6) Take 10 ml of deionized water, weigh 0.2564 g of Ga2(NO3)6·nH2O and 0.0185 g of SnCl2·4H2O according to a concentration of 1 mol / L, stir and dissolve them thoroughly to obtain a gallium nitrate aqueous solution;

[0166] (7) Pour 8 ml of the gallium nitrate aqueous solution prepared in step (6) into the inner container of the reactor, tighten the reactor, and then react the sealed reactor at 150°C for 24 hours. After the reaction is completed, cool it down naturally to room temperature.

[0167] (8) Take out the FTO substrate with the Ga2O3 textured film and clean it 4 times with ethanol and ultrasonic waves to remove the surface attachments;

[0168] (9) The FTO substrate taken out in (8) was placed in a high-temperature tube furnace and annealed at 850°C for 12 h to obtain a densely structured n-type β-Ga2O3 textured film on the FTO substrate.

[0169] Step b: Assemble the β-Ga2O3 textured film and the carbon nanotube film top electrode to obtain a Ga2O3-based Schottky diode unit

[0170] (1) The FTO substrate with n-type β-Ga2O3 textured film was cleaned with ethanol and deionized water in sequence, and then dried with a nitrogen gun for later use;

[0171] (2) Disperse 0.05 g of carbon nanotube powder in 20 ml of a mixed solution of chloroform and dimethylformamide (DMF), where the volume ratio of chloroform to dimethylformamide (DMF) is 1:1.

[0172] (3) Inject distilled water into the pulling machine until it reaches the horizontal position. Use a 1000ul syringe to draw 500ul of the solution prepared in step (2) and disperse it drop by drop into the distilled water. The carbon nanotubes will condense together on their own.

[0173] (4) By the Langmuir-Blodgett method, the FTO substrate with the n-type β-Ga2O3 textured film is inserted into the solution of step (3), and the surface film is slowly pulled up at a speed of 2 cm / min under a surface pressure of 30 Pa to obtain a Ga2O3-based Schottky diode unit.

[0174] Step c, attaching an ultra-thin 63Ni radiation source to obtain a wide bandgap oxide Schottky junction β-radiation voltaic nuclear battery;

[0175] (1) Self-supporting 63Ni radiation source film obtained by electroplating peeling;

[0176] 1. Dissolve 210g NiSO4·6H2O, 55g NiCl2·6H2O, 65g NaCl, and 30g H3BO3 in 1L deionized water and adjust the pH to 4.

[0177] 2. Pour the solution in 1 into the electroplating tank, and place the electroplating tank in a 25℃ water bath for 30 minutes;

[0178] 3. Place the ITO glass of 5cmx6cm in the electroplating tank and fix it vertically;

[0179] 4. Place a 5cmx6cm nickel sheet into the electroplating tank and place it parallel to the ITO sheet 3 at a distance of 9cm and fix it vertically.

[0180] 5. Connect the negative electrode of the electrochemical workstation to the ITO glass, and connect the reference electrode and counter electrode of the electrochemical workstation to the nickel sheet;

[0181] 6. Adopt the constant current electroplating method, set the initial voltage to 1.5 V, the output current to 100 mA, and the electroplating time to 42 min to obtain a nickel thin film grown on the surface of ITO.

[0182] 7. Take out the ITO glass with the nickel thin film in step 6, attach a transparent tape with a width of 5 cm, stick the nickel thin film on the tape, and then tear off the tape to obtain a transparent tape with a nickel thin film, where the transparent tape film is made of BOPP and the glue is made of acrylate glue;

[0183] 8. Flatten the transparent tape with the nickel thin film and gently place it on the surface of acetone liquid to dissolve the adhesive in the transparent tape to obtain a self-supporting ultra-thin 63Ni film with a thickness of 23 μm;

[0184] 9. Transfer the ultra-thin 63Ni film in step 8 to deionized water and wash it 5 times;

[0185] (2). Make one end of the ultra-thin 63Ni film contact with the Ga2O3-based Schottky diode unit, then gently pull out the Ga2O3-based film to make the two fully adhere, avoiding the generation of air bubbles in the middle. After the adhesion is completed, let the sample dry naturally and bake it at 100 °C in a vacuum state for 2 hours to make the 63Ni film and the Ga2O3-based diode film adhere tightly. After the baking is completed, take down the sample and let it cool naturally to room temperature to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery.

[0186] Example 5

[0187] A preparation method of a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery. Use the hydrothermal method to grow an n-type Ga2O3 textured film on the FTO substrate. Directly use the FTO substrate as the bottom electrode. Self-assemble carbon nanotubes on the surface of deionized water by the L-B film method to obtain a self-supporting carbon nanotube film. Use the prepared Ga2O3 film to fish up the carbon nanotube film in deionized water and assemble it to obtain a Ga2O3 Schottky diode device unit. Then, float and transfer the ultra-thin 63Ni film prepared by electroplating onto the Ga2O3 Schottky diode device unit and dry it to finally obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery. The specific steps are as follows:

[0188] Step a: Use the high-temperature hydrothermal method to grow a Ga2O3 textured film on the FTO substrate

[0189] (1). Cut the FTO substrate into a size of 2×1 cm 2 and wash it successively with acetone, ethanol, and deionized water. After the washing is completed, dry it for standby;

[0190] (2) Mix 5 ml of ethanol and 5 ml of deionized water thoroughly in a beaker. Then, weigh 0.2564 g of Ga2(NO3)6·nH2O according to a concentration of 1 mol / L and add it to the beaker, stirring well to obtain an aqueous solution of gallium nitrate in ethanol.

[0191] (3) Place the cleaned FTO substrate at an angle of 70° into the inner liner of a 10-ml reaction kettle, with the FTO side facing down. Pour the aqueous solution of gallium nitrate in ethanol into the inner liner of the reaction kettle and tighten the reaction kettle.

[0192] (4) React at 90 °C for 2 h. After the reaction is completed, allow it to cool naturally to room temperature.

[0193] (5) Open the reaction kettle that has completed the reaction and cooled in step (4), and suck out the solution in the inner liner of the reaction kettle to remove the solution after the reaction.

[0194] (6) Measure 10 ml of deionized water, add 0.0366 g of cetyltrimethylammonium bromide, and weigh 0.2564 g of Ga2(NO3)6·nH2O according to a concentration of 1 mol / L. Stir well to dissolve and obtain an aqueous solution of gallium nitrate.

[0195] (7) Pour 8 ml of the aqueous solution of gallium nitrate from step (6) into the inner liner of the reaction kettle, tighten the reaction kettle, and then react the sealed reaction kettle at 150 °C for 24 h. After the reaction is completed, allow it to cool naturally to room temperature.

[0196] (8) Take out the FTO substrate with the Ga2O3 textured film grown on it, and use ethanol and ultrasonic waves to clean it 4 times to remove the surface attachments.

[0197] (9) Place the FTO substrate taken out in step (9) into a high-temperature tube furnace and anneal it at 850 °C for 12 h to obtain a structurally dense n-type β-Ga2O3 textured film on the FTO substrate.

[0198] Step b: Assemble the β-Ga2O3 textured film and the carbon nanotube thin film top electrode to obtain a Ga2O3-based Schottky diode unit

[0199] (1) Clean the FTO substrate with the n-type β-Ga2O3 textured film successively with ethanol and deionized water, and then dry it with a nitrogen gun for later use.

[0200] (2) Disperse 0.05 g of carbon nanotube powder in a mixed solution of 20 ml of chloroform and dimethylformamide (DMF), where the volume ratio of chloroform to dimethylformamide (DMF) is 1:1.

[0201] (3) Inject distilled water into the puller until the water level reaches the designated position. Use a 1000 μl syringe to aspirate 500 μl of the solution prepared in step (2) and disperse it drop by drop into the distilled water. The carbon nanotubes will spontaneously aggregate together.

[0202] (4) Using the Langmuir-Blodgett method, immerse the FTO substrate with the n-type β-Ga2O3 textured film into the solution in step (3), and slowly pull it out at a speed of 0.5 cm / min under a surface film pressure of 35 Pa to obtain a Ga2O3-based Schottky diode unit.

[0203] Step c: Attach an ultra-thin 63Ni radiation source to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery.

[0204] (1) Use the electroplated and peeled self-supporting 63Ni radiation source thin film.

[0205] 1. Dissolve 210 g of NiSO4·6H2O, 55 g of NiCl2·6H2O, 65 g of NaCl, and 30 g of H3BO3 in 1 L of deionized water and adjust the pH value to 4.

[0206] 2. Pour the solution in 1 into the electroplating bath and place the electroplating bath in a 25 °C water bath for 30 min.

[0207] 3. Place a 5 cm x 6 cm ITO glass into the electroplating bath and fix it vertically.

[0208] 4. Place a 5 cm x 6 cm nickel sheet into the electroplating bath and fix it vertically parallel to the ITO in 3 at a distance of 9 cm.

[0209] 5. Connect the negative electrode of the electrochemical workstation to the ITO glass, and connect the reference electrode and counter electrode of the electrochemical workstation to the nickel sheet.

[0210] 6. Adopt the constant current electroplating method, set the initial voltage to 1.5 V, the output current to 100 mA, and the electroplating time to 42 min to obtain a nickel thin film grown on the surface of the ITO.

[0211] 7. Take out the ITO glass with the nickel thin film in 6, attach a 5 cm-wide transparent tape to it, stick the nickel thin film on the tape, and then tear off the tape to obtain a transparent tape with a nickel thin film. The transparent tape film is made of BOPP, and the glue is made of acrylate glue.

[0212] 8. Flatten the transparent tape with the nickel thin film and gently place it on the surface of the acetone liquid to dissolve the adhesive in the transparent tape to obtain a self-supporting ultra-thin 63Ni film with a thickness of 23 μm.

[0213] 9. Transfer the 8 ultra-thin 63Ni films into deionized water and wash them 5 times;

[0214] (2) Use an ultra-thin 63Ni film to contact one end of the Ga2O3-based Schottky diode unit, then gently pull out the Ga2O3-based film to make the two completely attached to avoid bubbles in the middle. After the attachment is completed, the sample is naturally dried and dried at 100°C in a vacuum state for 2 hours to make the 63Ni film and the Ga2O3-based diode film tightly attached. After the baking is completed, the sample is removed and naturally cooled to room temperature to obtain a wide bandgap oxide Schottky junction β-radiation voltaic nuclear battery.

[0215] Example 6

[0216] A method for preparing a wide-bandgap oxide Schottky junction β-nuclear battery cell comprises growing an n-type Ga2O3 textured film on an FTO substrate by a hydrothermal method, directly using the FTO substrate as a bottom electrode, protecting the FTO substrate on which the Ga2O3 textured film is grown to leave a position for the electrode, and using electron beam thermal evaporation technology to evaporate a Ni / Au electrode on the Ga2O3 textured film to obtain a Ga2O3 Schottky diode device unit. Subsequently, an ultra-thin 63Ni film prepared by electroplating is float-transferred onto the Ga2O3 Schottky diode device unit, and drying is performed to finally obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery. The specific steps are as follows:

[0217] Step a: Growth of Ga2O3 textured film on FTO substrate using high temperature hydrothermal method

[0218] (1) Cut the FTO substrate into 2×1cm 2 Use acetone, ethanol and deionized water to clean the size in sequence, and dry it after cleaning;

[0219] (2) Mix 5 ml of ethanol and 5 ml of deionized water in a beaker, then weigh 0.2564 g of Ga2(NO3)6·nH2O at a concentration of 1 mol / L and add it to the beaker and stir thoroughly to obtain a gallium nitrate ethanol aqueous solution;

[0220] (3) Tilt the cleaned FTO substrate 60° and place it in a 10ml reactor liner with the FTO side facing down. Pour 8ml of gallium nitrate ethanol aqueous solution into the reactor liner and tighten the reactor.

[0221] (4) React at 100 °C for 1 h, and then cool naturally to room temperature after the reaction is completed;

[0222] (5) Open the reactor after the reaction in (4) is completed and cooled, and the solution in the reactor liner is sucked out to remove the reacted solution.

[0223] (6) Measure 10 ml of deionized water, weigh 0.2564 g of Ga2(NO3)6·nH2O according to a concentration of 1 mol / L, and stir well to dissolve it to obtain an aqueous solution of Ga2(NO3)6·nH2O with a concentration of 1 mol / L;

[0224] (7) Pour 8 ml of the gallium nitrate aqueous solution from step (6) into the inner liner of the reaction kettle, tighten the reaction kettle, and then react the sealed reaction kettle at 150 °C for 24 h. After the reaction is completed, naturally cool it to room temperature;

[0225] (8) Take out the FTO substrate with the Ga2O3 texture film grown on it, and use ethanol and ultrasonic waves to clean it 3 times to remove the surface attachments;

[0226] (9) Put the FTO substrate taken out in (8) into a high-temperature tube furnace and anneal it at 550 °C for 12 h to obtain a structurally dense n-type β-Ga2O3 texture film on the FTO substrate.

[0227] Step b: Assemble the β-Ga2O3 texture film and the metal Ni / Au film top electrode to obtain a Ga2O3-based Schottky diode unit;

[0228] (1) Clean and dry the FTO substrate with the n-type β-Ga2O3 texture film, and stick it on the carrier plate;

[0229] (2) Open the thermal evaporation chamber, put the carrier plate into the chamber, attach it to the upper evaporation area, put Ni particles and Au particles into the two heating crucibles of the thermal evaporator respectively, and close the evaporation chamber;

[0230] (3) Evaporate under the condition that the vacuum degree is 5×10 -4 Pa. First, evaporate the Ni layer as the first layer of the electrode, with a current of 70 A, evaporate 50 nm of Ni as the adhesion layer, and evaporate 150 nm of Au as the electrode layer on the basis of the Ni layer at a current between 60 A. After the temperature cools to room temperature, take out the Ga2O3-based Schottky diode unit with the Ni / Au electrode.

[0231] Step c: Attach the ultra-thin 63Ni radiation source to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery;

[0232] (1) Use the self-supporting 63Ni radiation source film obtained by electroplating and stripping;

[0233] 1. Dissolve 210 g of NiSO4·6H2O, 55 g of NiCl2·6H2O, 65 g of NaCl, and 30 g of H3BO3 in 1 L of deionized water, and adjust the pH value to 4;

[0234] 2. Pour the solution in 1 into the electroplating bath, and place the electroplating bath in a water bath at 25 °C for 30 min.

[0235] 3. Place the ITO glass with a size of 5 cm x 6 cm into the electroplating bath and fix it vertically.

[0236] 4. Place the nickel sheet with a size of 5 cm x 6 cm into the electroplating bath and place it parallel to the ITO in 3, with a vertical fixation at a distance of 9 cm.

[0237] 5. Connect the negative electrode of the electrochemical workstation to the ITO glass, and connect the reference electrode and counter electrode of the electrochemical workstation to the nickel sheet.

[0238] 6. Adopt the constant current electroplating method, set the initial voltage to 1.5 V, the output current to 100 mA, and the electroplating time to 42 min to obtain a nickel thin film grown on the surface of the ITO.

[0239] 7. Take out the ITO glass with the nickel thin film in 6, attach a transparent tape with a width of 5 cm, stick the nickel thin film on the tape, and then tear off the tape to obtain a transparent tape with a nickel thin film, where the transparent tape film is made of BOPP and the glue is made of acrylate glue.

[0240] 8. Flatten the transparent tape with the nickel thin film and gently place it on the surface of the acetone liquid to dissolve the adhesive in the transparent tape to obtain a self-supporting ultra-thin 63Ni film with a thickness of 23 μm.

[0241] 9. Transfer the ultra-thin 63Ni film in 8 to deionized water and wash it 5 times.

[0242] (2). Make one end of the ultra-thin 63Ni film contact with the Ga2O3-based Schottky diode unit, then gently pull out the Ga2O3-based film to make the two fully adhere, avoiding the generation of bubbles in the middle. After the adhesion, let the sample dry naturally and bake it at 100 °C in a vacuum state for 2 hours to make the 63Ni film and the Ga2O3-based diode film adhere tightly. After the baking, take down the sample and let it cool naturally to room temperature to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery.

[0243] Example 7

[0244] A method for preparing a wide-bandgap oxide Schottky junction β-nuclear battery cell comprises growing an n-type Ga2O3 textured film on an FTO substrate by a hydrothermal method, directly using the FTO substrate as a bottom electrode, protecting the FTO substrate on which the Ga2O3 textured film is grown to leave a position for the electrode, and using electron beam thermal evaporation technology to evaporate a Ni / Au electrode on the Ga2O3 textured film to obtain a Ga2O3 Schottky diode device unit. Subsequently, an ultra-thin 63Ni film prepared by electroplating is float-transferred onto the Ga2O3 Schottky diode device unit, and drying is performed to finally obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery. The specific steps are as follows:

[0245] Step a: Growth of Ga2O3 textured film on FTO substrate using high temperature hydrothermal method

[0246] (1) Cut the FTO substrate into 2×1cm 2 Use acetone, ethanol and deionized water to clean the size in sequence, and dry it after cleaning;

[0247] (2) Mix 5 ml of ethanol and 5 ml of deionized water in a beaker, then weigh 0.2564 g of Ga2(NO3)6·nH2O at a concentration of 1 mol / L and add it to the beaker and stir thoroughly to obtain a gallium nitrate ethanol aqueous solution;

[0248] (3) Tilt the cleaned FTO substrate 60° and place it in a 10ml reactor liner with the FTO side facing down. Pour 8ml of gallium nitrate ethanol aqueous solution into the reactor liner and tighten the reactor.

[0249] (4) React at 100 °C for 1 h, and then cool naturally to room temperature after the reaction is completed;

[0250] (5) Open the reactor after the reaction in (4) is completed and cooled, and the solution in the reactor liner is sucked out to remove the reacted solution.

[0251] (6) Take 10 ml of deionized water, weigh 0.2564 g of Ga2(NO3)6·nH2O according to the concentration of 1 mol / L, stir and dissolve it thoroughly to obtain a Ga2(NO3)6·nH2O aqueous solution with a concentration of 1 mol / L;

[0252] (7) Pour 8 ml of the gallium nitrate aqueous solution prepared in step (6) into the inner container of the reactor, tighten the reactor, and then react the sealed reactor at 150°C for 24 hours. After the reaction is completed, cool it down naturally to room temperature.

[0253] (8) Take out the FTO substrate with the Ga2O3 textured film and clean it three times with ethanol and ultrasonic waves to remove the surface attachments;

[0254] (9) Take out the FTO substrate from (8) and anneal it in a high-temperature tube furnace at 550 °C for 12 h to obtain a structurally dense n-type β-Ga2O3 textured film on the FTO substrate.

[0255] Step b: Assemble the β-Ga2O3 textured film with a metal Ni / Au film top electrode to obtain a Ga2O3-based Schottky diode unit;

[0256] (1) Clean and dry the FTO substrate with an n-type β-Ga2O3 textured film, and place it on the carrier plate;

[0257] (2) Open the thermal evaporation chamber, put the carrier plate into the chamber, attach it to the upper evaporation area, put Ni particles and Au particles into two heating crucibles of the thermal evaporator respectively, and close the evaporation chamber;

[0258] (3) Evaporate under the condition that the vacuum degree is 1×10 -4 Pa. First, evaporate Ni as the first layer with a current of 80 A and deposit 50 nm of Ni as the adhesion layer. Then, deposit a 150 nm Au layer on Ni as the electrode layer with a current of 50 A. Take out the Ga2O3-based Schottky diode unit with Ni / Au electrodes after the temperature cools down to room temperature.

[0259] Step c: Attach an ultra-thin 63Ni radiation source to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery;

[0260] (1) Use electroplating stripping to obtain a self-supporting 63Ni radiation source thin film;

[0261] 1. Dissolve 210 g of NiSO4·6H2O, 55 g of NiCl2·6H2O, 65 g of NaCl, and 30 g of H3BO3 in 1 L of deionized water and adjust the pH value to 5;

[0262] 2. Pour the solution in 1 into the electroplating bath, and put the electroplating bath into a 25 °C water bath for 30 min;

[0263] 3. Put an ITO glass with a size of 5 cm x 6 cm into the electroplating bath and fix it vertically;

[0264] 4. Put a nickel sheet with a size of 5 cm x 6 cm into the electroplating bath and place it parallel to the ITO in 3 at a distance of 10 cm and fix it vertically;

[0265] 5. Connect the negative electrode of the electrochemical workstation to the ITO glass, and connect the reference electrode and counter electrode of the electrochemical workstation to the nickel sheet;

[0266] 6. Adopt the constant current electroplating method, set the initial voltage at 1.5 V, the output current at 100 mA, and the electroplating time at 42 min to obtain a nickel thin film grown on the surface of ITO.

[0267] 7. Take out the ITO glass with the nickel thin film in step 6, attach a transparent tape with a width of 5 cm, stick the nickel thin film on the tape, and then tear off the tape to obtain a transparent tape with the nickel thin film, where the transparent tape film is made of BOPP and the adhesive is made of acrylate glue.

[0268] 8. Flatten the transparent tape with the nickel thin film and gently place it on the surface of acetone liquid to dissolve the adhesive in the transparent tape to obtain a self-supporting ultra-thin 63Ni thin film with a thickness of 20 μm.

[0269] 9. Transfer the ultra-thin 63Ni thin film in step 8 to deionized water and wash it 4 times.

[0270] (2) Make one end of the ultra-thin 63Ni thin film contact with a Ga2O3-based Schottky diode unit, then gently draw out the Ga2O3-based thin film to make the two completely adhere, avoiding the generation of air bubbles in the middle. After the adhesion is completed, let the sample dry naturally and bake it at 100 °C in a vacuum state for 2 hours to make the 63Ni thin film tightly adhere to the Ga2O3-based diode thin film. After the baking is completed, take down the sample and let it cool naturally to room temperature to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery.

Claims

1. A preparation method of a wide bandgap oxide Schottky junction β nuclear battery unit, characterized in that The specific process is as follows: first, an n-type β-Ga2O3 textured film is grown on a substrate through a two-step hydrothermal method. Then, after high-temperature annealing, it is assembled with a graphene, carbon nanotube, or metal Ni / Au film top electrode to obtain a Ga2O3-based Schottky diode unit. Finally, an ultra-thin 63Ni radiation source film is attached to the Ga2O3-based Schottky diode unit to obtain a wide-bandgap oxide Schottky junction β-radiation voltaic nuclear battery. Step a: hydrothermally growing an n-type Ga2O3 textured film on an FTO substrate using gallium nitrate as a gallium source via a two-step process. In the first step, a mixed solution of ethanol and deionized water is used as a solvent to grow a Ga2O3 seed layer. In the second step, an aqueous solution is used to grow a Ga2O3 textured film. After the two-step hydrothermal growth, a high-temperature annealing step is performed to obtain an n-type β-Ga2O3 textured film. Step b, on the surface of the n-type β-Ga2O3 textured film, a graphene top electrode is covered by floating transfer, a metal Ni / Au film top electrode is deposited by electron beam thermal evaporation, or a carbon nanotube film top electrode is constructed by LB film method to obtain a Ga2O3-based Schottky diode unit; Step c, attaching the obtained Ga2O3-based Schottky diode unit to a self-supporting ultra-thin 63Ni radiation source film prepared by electroplating through floating transfer, naturally drying and baking the sample after the attachment, removing the sample after the baking and naturally cooling it to room temperature to obtain a wide bandgap oxide Schottky junction β-radiation voltaic nuclear battery; The steps are described as follows: Step a: growing an n-type β-Ga2O3 textured thin film on a FTO substrate by a hydrothermal method: (1) Use acetone, ethanol, and deionized water to clean the FTO substrate in sequence, and dry it after cleaning; (2) Fully mix ethanol and deionized water in a volume ratio of 1:1, then add Ga2(NO3)6·nH2O and stir thoroughly to form a Ga2(NO3)6·nH2O ethanol aqueous solution with a concentration of 1 mol / L; (3) Place the cleaned FTO substrate in a 10ml reactor at an angle, and add 8ml of Ga2(NO3)6·nH2O ethanol aqueous solution into the reactor, with the FTO surface facing downwards. (4) The reaction kettle was sealed and reacted at 90-100°C for 1-2 hours. After the reaction was completed, the solution in the reactor was removed after the reaction was naturally cooled to room temperature; (5) Add Ga2(NO3)6·nH2O to deionized water and stir thoroughly to dissolve to form a 1 mol / L Ga2(NO3)6·nH2O aqueous solution, add 8 ml into the reactor of step (4), seal the reactor and react at 140-170°C for 24-36 hours, and cool naturally to room temperature after the reaction to obtain an FTO substrate with a Ga2O3 textured film; (6) Place the FTO substrate with the Ga2O3 textured film in a high-temperature furnace and anneal at 550-850°C for 12-18 hours to obtain a dense n-type β-Ga2O3 textured film on the FTO substrate; Step b, assembling the β-Ga2O3 textured film and the graphene top electrode to obtain a Ga2O3-based Schottky diode unit; (1) Grow single-crystal graphene on the surface of a Cu foil by the CVD method, then cover the graphene with a PMMA film, and subsequently place it in a 3 mol / L iron(III) chloride (FeCl3) solution for etching for 30 - 60 min to completely remove the Cu, so that the PMMA-protected graphene film floats on the surface of the solution for use; (2) Gently drag out the PMMA-protected graphene film with an FTO substrate with a β-Ga2O3 textured film and transfer it to deionized water, keep it floating, soak for 30 - 60 min to completely remove the iron(III) chloride, and then dry it at 40 - 100 °C for 2 - 4 hours under vacuum to make the graphene film tightly adhere to the Ga2O3 textured film, obtaining a Ga2O3-based Schottky diode unit; Step c: Attach a self-supporting ultra-thin 63Ni radiation source film with a thickness of 20 - 23 μm prepared by electroplating. After the attachment, dry the sample in a vacuum oven at 40 - 100 °C for 2 - 4 hours, and then take down the sample and let it cool naturally to room temperature to obtain a wide-bandgap oxide Schottky junction β-radiovoltaic nuclear battery.

2. The preparation method of a wide bandgap oxide Schottky junction β nuclear battery unit according to claim 1, characterized in that The said step b is: (1) Clean the FTO substrate with an n-type β-Ga2O3 textured film successively with ethanol and deionized water, and then dry it with a nitrogen gun for use; (2) Disperse 0.05 g of carbon nanotube powder in a mixed solution of 10 ml of chloroform and dimethylformamide (DMF), where the volume ratio of chloroform to dimethylformamide (DMF) is 1:1; (3) Inject distilled water into the puller until the water level in the puller is reached, and use a 1000 μl syringe to suck 500 μl of the solution prepared in step (2) and disperse it drop by drop into the distilled water; (4) Immerse the FTO substrate with an n-type β-Ga2O3 textured film into the solution in step (3) by the Langmuir-Blodgett method, and slowly pull it up at a speed of 0.5 - 2 cm / min under a surface film pressure of 30 - 35 Pa to obtain a Ga2O3-based Schottky diode unit.

3. The preparation method of a wide bandgap oxide Schottky junction β nuclear battery unit according to claim 1, characterized in that The said step b is: (1) Clean and dry the FTO substrate with an n-type β-Ga2O3 textured film, and place it on the carrier plate; (2) Open the thermal evaporation chamber, place the carrier plate in the chamber and attach it to the upper evaporation area. Put Ni particles and Au particles in two heating crucibles of the thermal evaporator respectively, and close the evaporation chamber; (3) When the vacuum degree is 1×10 -4 -5×10 -4 Pa was evaporated under the conditions of first evaporating Ni as the first layer with a current of 70-80A, and then 50nmNi was evaporated as the adhesion layer. Then 150nmAu was evaporated as the electrode layer on the basis of the Ni layer with a current of 50-60A. After the temperature cooled, the Ga2O3-based Schottky diode unit with Ni / Au electrode was taken out.

4. The preparation method of a wide bandgap oxide Schottky junction β nuclear battery unit according to claim 1, characterized in that The method for growing single-crystal graphene by the CVD method is: (1) Copper foil preparation: Put two copper foils with a thickness of 20 - 25 μm into acetone, alcohol, and deionized water for cleaning respectively, then dry the surface of the copper foils with high-purity nitrogen. After drying, place them in a CVD tube furnace and heat up to 1000 - 1050 °C. First, introduce H2 for cleaning for 1 - 1.2 h, and then introduce CH4 for cleaning for 1 - 1.2 h; (2) Copper foil annealing: Anneal the copper foil at 1000 - 1050 °C for 30 - 90 min in an H2 atmosphere; (3) Introduce carbon source: At a temperature of 1000 - 1050 °C, introduce a mixed gas of H2 and CH4 with a volume ratio of 99:1, and maintain for 10 - 20 minutes. (4) Cool down: Continuously introduce a mixed gas of H2 and CH4 with a volume ratio of 99:

1. When the temperature drops to 250 - 300 °C, directly open the furnace body. When the furnace temperature rapidly drops below 40 °C, take out the copper foil with graphene attached. (5) Coating: Take out the copper foil with graphene attached and place it on a spin coater. Drop 200 μl of a polymethyl methacrylate (PMMA) solution with a mass concentration of 5.5%. First, run at 500 - 800 rmp for 10 - 30 seconds, and then run at a high speed of 3000 - 5000 rmp for 20 - 40 seconds to spin coat and form graphene covered with a PMMA film.

5. The preparation method of a wide bandgap oxide Schottky junction β nuclear battery unit according to claim 3 or 4, characterized in that In the second step of step a when growing the Ga2O3 textured film using an aqueous solution, metal salts of metal elements Ni, Sn, Al, and Mn are added to achieve doping modification.

6. The preparation method of a wide-bandgap oxide Schottky junction β nuclear battery unit according to claim 5, characterized in that In the second step of step a when growing the Ga2O3 textured film using an aqueous solution, a surfactant such as cetyltrimethylammonium bromide or sodium dodecyl sulfate is used to regulate the surface growth state of gallium oxide, and a Ga2O3 textured film with a denser surface state is obtained.

7. The preparation method of a wide-bandgap oxide Schottky junction β nuclear battery unit according to claim 1 or 6, characterized in that The specific method for obtaining the self - supported 63Ni radiation source film using electroplating in step c is as follows: (1) Dissolve 210 g of NiSO4·6H2O, 55 g of NiCl2·6H2O, 65 g of NaCl, and 30 g of H3BO3 in 1 L of deionized water, and adjust the pH value to 4 - 5. (2) Pour the solution in (1) into an electroplating bath, and place the electroplating bath in a water bath at 25 - 30 °C for 30 - 60 minutes. (3) Place ITO glass with a size of 5 cm x 6 cm into the electroplating bath and fix it vertically. (4) Place a nickel sheet with a size of 5 cm x 6 cm into the electroplating bath and place it parallel to the ITO in (3) at a distance of 8 - 10 cm and fix it vertically. (5) Connect the negative electrode of the electrochemical workstation to the ITO glass, and connect the reference electrode and counter electrode of the electrochemical workstation to the nickel sheet. (6) Using the constant - current electroplating method, set the initial voltage to 1.5 V, the output current to 100 mA, and the electroplating time to 40 - 45 minutes to obtain a nickel film grown on the ITO surface. (7) Take out the ITO glass with the nickel film in (6), attach a transparent tape with a width of 5 cm, stick the nickel film on the tape, and then tear off the tape to obtain a transparent tape with a nickel film. (8) Flatten the transparent tape with the nickel film and gently place it on the surface of acetone liquid to dissolve the adhesive in the transparent tape to obtain a self - supported nickel film. (9) Transfer the nickel film in (8) to deionized water and wash it 3 - 5 times.

Images