Silicon-based size-controllable β-Ga 2 O 3 Preparation method of nanowires

Abstract

The present invention discloses a method for preparing silicon-based size-controllable β-Ga2O3 nanowires. The preparation process of the silicon-based size-controllable β-Ga2O3 nanowires is as follows: First, a gold (Au) catalytic layer with different thicknesses is deposited on a single-crystal Si(100) substrate, and the catalytic layer is subjected to in-situ spheroidizing annealing to obtain Au nanoparticles with different sizes. Then, β-Ga2O3 nanowires are grown by magnetron sputtering and in-situ annealed to obtain β-Ga2O3 nanowires with different sizes. By regulating the size of the β-Ga2O3 nanowires, the present invention can obtain β-Ga2O3 nanowires with the advantages of few defects, high resistivity, uniform density, etc. The β-Ga2O3 nanowires with different sizes prepared by the present invention exhibit excellent performance in the application of solar-blind ultraviolet detectors, and can be applied to missile approaching warning systems, ultraviolet communication, ultraviolet imaging navigation, etc. in the military field, and have broad application prospects in aspects such as automobile exhaust detection, flame detection, and fingerprint detection in the civilian field.

Description

Technical Field

[0001] The present invention relates to a method for regulating the diameter size of gallium oxide (Ga 2 O 3 ) nanowires, belonging to the technical field of semiconductor material manufacturing processes. Background Art

[0002] Ga 2 O 3 is an important compound semiconductor material. It has the advantages of good thermal stability, large optical absorption coefficient, high chemical stability, high Baliga figure of merit, and low preparation cost. Ga 2 O 3 has multiple isomers, which are respectively denoted as α-Ga 2 O 3 , β-Ga 2 O 3 , γ-Ga 2 O 3 , δ-Ga 2 O 3 , ε-Ga 2 O 3 . The differences between them lie not only in the crystal space type but also in the coordination number of gallium ions in the lattice. Different phases of Ga 2 O 3 can be regulated by different preparation methods and special conditions. Among these isomers of Ga 2 O 3 , only the monoclinic β-Ga 2 O 3 is the stable phase. β-Ga 2 O 3 can be transformed from other metastable phases through long-time high-temperature treatment in air. Therefore, β-Ga 2 O 3 is the most promising stable structure for wide optical applications.

[0003] The main methods for preparing β-Ga 2 O 3 include: magnetron sputtering, metalorganic chemical vapor deposition, pulsed laser deposition, molecular beam epitaxy, etc. Compared with other growth technologies, magnetron sputtering technology is simple to operate and can achieve large-area coating. The prepared material has strong adhesion and a relatively uniform structure. Currently, when growing Ga 2 O 3The substrates include SiC, sapphire, diamond, GaN, Si, etc. Among them, substrates such as SiC, sapphire, diamond, and GaN are relatively expensive and the substrate preparation processes are not yet mature. Polyethylene terephthalate (PET) as a flexible substrate can enhance the bending characteristics of the device, but it cannot withstand high temperatures. Ga 2 O 3 needs to be grown in a high-temperature environment. Silicon substrate materials are abundant and have good thermal stability and device integration. Therefore, using silicon as the substrate to prepare high-quality Ga 2 O 3 is beneficial to the preparation and integrated application of Ga 2 O 3 -based devices.

[0004] So far, silicon-based β-Ga 2 O 3 has different forms: single crystal, thin film and other structures. These structures have been applied to the preparation of solar-blind ultraviolet detectors, but the preparation processes are not yet mature. Although single crystal β-Ga 2 O 3 has excellent performance, its preparation is difficult and the requirements for equipment are high. β-Ga 2 O 3 thin film is easy to prepare, but due to the existence of internal stress, its internal structure has the disadvantages of more defects and poor compactness, resulting in a large leakage current in the prepared device. Moreover, the contact area between the β-Ga 2 O 3 thin film-based detector and the incident light is small. Therefore, to improve the photoelectric detection performance of the β-Ga 2 O 3 solar-blind ultraviolet detector, we propose to prepare silicon-based β-Ga 2 O 3 nanowires by using an Au layer as a catalyst, so as to improve the structural compactness and light contact area of β-Ga 2 O 3 and control the size of the nanowires by controlling the thickness of the Au catalytic layer. Improve the quality of the nanowires through processes such as front-spheroidizing annealing treatment and post-annealing treatment, and then reduce the influence of grain boundaries and defects. High-quality β-Ga 2 O 3 nanowires can be used to prepare solar-blind ultraviolet detectors with higher responsivity and faster response speed, and can be widely applied in military fields: missile approach warning systems, ultraviolet communication, ultraviolet imaging assisted navigation, etc., and can also be widely applied in civilian fields: monitoring of automobile exhaust, flame detection, DNA testing, etc. Summary of the Invention

[0005] To solve the problems of the existing technology, the purpose of the present invention is to overcome the deficiencies of the prior art and provide a method for preparing silicon-based size-controllable β-Ga 2 O 3 nanowires. By controlling the size of the β-Ga 2 O 3 nanowires, β-Ga 2 O 3 nanowires with the advantages of few defects, high resistivity, uniform density, etc. can be obtained.

[0006] To achieve the above object of the invention-creation, the present invention adopts the following technical solutions:

[0007] A method for preparing silicon-based size-controllable β-Ga 2 O 3 nanowires, comprising the following steps:

[0008] (1) Preparation of the Au catalytic layer:

[0009] Using the electron beam sputtering deposition method, a 10-40 nm thick Au catalytic layer is grown on the cleaned and surface-state-treated single-crystal (100) Si substrate, and the size of the β-Ga 2 O 3 nanowires is controlled by controlling the thickness of the catalytic layer; the Au used is high-purity Au, and according to the calculation method of the metal purity based on the impurity concentration ratio of the metal, the metal purity is 99-99.99999%;

[0010] (2) Growth process of the β-Ga 2 O 3 nanowires:

[0011] Using the magnetron sputtering method, β-Ga 2 O 3 nanowires are grown on the substrate with the Au catalytic layer prepared in the step (1); the purity of the Ga 2 O 3 target material is not less than 99.99%; before the formal sputtering, the Au catalytic layer is pre-treated at not less than 600 °C for at least 30 minutes, and the Au catalytic layer is subjected to in-situ spheroidizing annealing to make it into Au nanoparticles; then the formal sputtering is carried out, and the substrate temperature is continuously raised to not less than 700 °C, and Ar gas is introduced to generate a glow plasma, thereby preparing β-Ga 2 O 3 nanowires;

[0012] (3) In-situ annealing treatment of the β-Ga 2 O 3 nanowires:

[0013] The β-Ga prepared in the step (2) is2 O 3 The nanowires are subjected to in-situ post-annealing treatment at an annealing temperature of not less than 700 °C to obtain β-Ga 2 O 3 nanowires with a uniform and dense structure. After the annealing is completed, the sample is cooled to room temperature, and the silicon-based β-Ga 2 O 3 nanowire finished products are taken out.

[0014] Preferably, in the step (1), an Au catalyst layer is grown on the substrate by electron beam sputtering deposition.

[0015] Preferably, in the step (1), the thickness of the Au catalyst layer prepared on the substrate is 10 - 30 nm.

[0016] Preferably, in the step (1), after pickling the single-crystal (100) Si substrate, it is pre-treated at not less than 300 °C for at least 30 minutes to obtain a clean and dry substrate surface state.

[0017] Preferably, in the step (1), when pickling the single-crystal (100) Si substrate, calculated by volume ratio, a solution with a ratio of HF:H 2 O of 1:9 is used for pickling to remove the oxide on the surface of the Si substrate.

[0018] Preferably, in the step (2), a radio frequency magnetron preparation method is adopted, and the background vacuum of the sputtering chamber is controlled to be not higher than 10 -7 Torr, the sputtering gas pressure is not higher than 10 -3 Torr, the sputtering power is not less than 200 W, and the sputtering time is at least 300 minutes.

[0019] Preferably, in the step (2), the heating rate in each heating stage is controlled to be not less than 10 °C / min.

[0020] Preferably, in the step (2), the argon is high-purity argon with a purity of not less than 99.999%, and the flow rate is at least 32 sccm.

[0021] Preferably, in the step (3), the annealing time is at least 1 h.

[0022] Preferably, in the step (2), the Au catalyst layer is subjected to in-situ spheroidizing annealing, and the width dimension of the Au nanoparticles after spheroidizing annealing is 100 - 200 nm; then in the step (3), the β-Ga 2 O 3 nanowire structure diameter of the silicon-based β-Ga2O3 nanowire finished product is 100 - 200 nm.

[0023] Compared with the prior art, the present invention has the following obvious outstanding substantial features and remarkable advantages:

[0024] 1. The present invention grows β-Ga 2 O 3 nanowires on a single crystal (100) Si substrate. Compared with β-Ga 2 O 3 nanowires grown on other oriented Si substrates, the β-Ga 2 O 3 nanowires grown on the single crystal (100) Si substrate have a better lattice match, and the prepared nanostructures are denser and have a lower surface roughness;

[0025] 2. The present invention adopts a radio frequency magnetron preparation process, which is simpler in operation, lower in cost, can be prepared on a large scale, and has a high feasibility for batch growth compared with other growth processes;

[0026] 3. The present invention regulates the size of β-Ga 2 O 3 nanowires by setting different Au catalyst layer thicknesses, reduces the influence of grain boundaries and defects, and realizes a faster carrier transport speed when preparing a solar-blind ultraviolet detector, achieving a faster response;

[0027] 4. The method of the present invention is simple and feasible, low in cost, and suitable for popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a flowchart for preparing β-Ga 2 O 3 nanowires of the present invention.

[0029] Figure 2 is a surface morphology diagram of silicon-based β-Ga 2 O 3 nanowires prepared in Example 1 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0030] The above solution will be further described below in conjunction with specific implementation examples. The preferred implementation examples of the present invention are described in detail as follows:

[0031] Example 1:

[0032] In this example, a 10-nm Au catalyst layer is prepared on a single crystal (100) Si substrate. According to the calculation method of the metal purity based on the impurity concentration ratio of the metal, high-purity Au with a purity of 99.999% is selected as the material for electron beam evaporation; the Au catalyst layer is subjected to spheroidizing annealing treatment at 600 °C before sputtering, and then the temperature is raised to 700 °C for formal sputtering of Ga 2 O 3 ; Ga 2 O3 The purity of the target material is 99.99%, and finally in-situ annealing is carried out at 700 °C.

[0033] A method for controllably preparing silicon-based β-Ga 2 O 3 nanowires, comprising the following steps:

[0034] (1) Substrate cleaning and pretreatment:

[0035] Select a single-crystal (100) Si substrate with a size of 20 mm × 20 mm and a thickness of 0.5 mm; the substrate is ultrasonically treated in deionized water, acetone, absolute ethanol, and deionized water for 5 minutes each in sequence, then pickled in a diluted HF solution for 2 minutes, and finally cleaned in deionized water for 5 minutes and dried with high-purity nitrogen to obtain a clean and dry substrate; in order to make up for the change in the substrate surface state caused by pickling to remove surface oxides, the washed substrate is quickly transferred into a vacuum chamber and treated at a temperature of 300 °C for 30 minutes to improve the substrate surface state;

[0036] (2) Preparation of the Au catalyst layer

[0037] Using the electron beam sputtering deposition method, grow an Au catalyst layer with a thickness of 10 nm on the Si substrate whose surface state has been treated in the step (1); the metal used is high-purity Au, and according to the calculation method of the metal purity based on the impurity concentration ratio contained in the metal, the metal purity is 99.999%; the electron beam voltage is 9.7 keV, the power is set to 39.6%, the rate is 0.6 A / s, and the growth temperature is room temperature;

[0038] (3) Growth of β-Ga 2 O 3 nanowires

[0039] Put the substrate with a 10-nm-thick Au catalyst layer prepared in the step (2) into the vacuum chamber, turn on the rotation, the rotation rate is 5 rpm, raise the substrate temperature to 600 °C at a heating rate of 10 °C / min, and keep it at this temperature for 30 minutes; the purpose of this is to carry out in-situ spheroidizing annealing on the Au catalyst layer to make it into Au nanoparticles; then raise the substrate temperature to 700 °C, fill the chamber with high-purity argon for formal deposition, the flow rate is controlled at 32 sccm, the sputtering power is set to 200 W, and the sputtering time is controlled for 300 minutes;

[0040] (4) In-situ annealing treatment of β-Ga 2 O 3 nanowires

[0041] After the sample growth is completed, it is annealed in situ at 700℃ for 1h; the purpose is to allow the atoms to obtain sufficient time and energy for diffusion and fusion, so as to obtain a more uniform and dense sample; after the annealing is completed, the temperature is lowered to room temperature at a cooling rate of 10℃ / min, the rotation is turned off, and the sample is taken out.

[0042] Experimental test analysis:

[0043] In this embodiment, the size of Au nanoparticles after spheroidization annealing is 100 nm. 2 O 3 The diameter of the nanowire structure is 100nm. After growing a Ti / Au composite electrode on the sample, a solar-blind ultraviolet detector was prepared. The dark current was 1.99E-10A, the photocurrent was 3.5E-6A, the response rise time was 0.34s, and the fall time was 0.57s. In order to adapt to the application of solar-blind ultraviolet detectors, the present invention prepares high-quality β-Ga on a single crystal (100) Si substrate. 2 O 3 Nanowires can significantly make up for the defects of thin films. 2 O 3 Nanowires and polycrystalline β-Ga 2 O 3 Compared with thin films, it has the advantages of fewer defects, higher resistivity, and larger light contact area, making it suitable for making solar-blind ultraviolet detectors.

[0044] Embodiment 2:

[0045] This embodiment is basically the same as the first embodiment, except that:

[0046] In this embodiment, a 20 nm thick Au catalyst layer is prepared on a single crystal (100) Si substrate. According to the impurity concentration ratio contained in the metal as the calculation method of the metal purity, high-purity Au with a purity of 99.999% is selected as the material for electron beam evaporation; before sputtering, the Au catalyst layer is subjected to spheroidization annealing at 600°C, and then the temperature is raised to 700°C for formal sputtering of Ga 2 O 3 ; Ga 2 O 3 The target material purity is 99.99%, and finally an in-situ annealing is performed at 700°C.

[0047] A silicon-based β-Ga 2 O 3 A method for preparing nanowires with controllable size comprises the following steps:

[0048] (1) Substrate cleaning and pretreatment:

[0049] A single crystal (100) Si substrate with a size of 20 mm × 20 mm and a thickness of 0.5 mm was selected. The substrate was ultrasonically treated in deionized water, acetone, absolute ethanol, and deionized water for 5 minutes each in sequence, then pickled in a diluted HF solution for 2 minutes, and finally washed in deionized water for 5 minutes, and dried with high-purity nitrogen to obtain a clean and dry substrate. To compensate for the change in the substrate surface state caused by pickling to remove surface oxides, the washed substrate was quickly transferred into a vacuum chamber and treated at a temperature of 300 °C for 30 minutes to improve the substrate surface state.

[0050] (2) Preparation of the Au catalytic layer

[0051] The electron beam sputtering deposition method was used to grow a 20-nm-thick Au catalytic layer on the Si substrate treated for surface state in step (1). The metal used was high-purity Au. According to the calculation method of metal purity based on the impurity concentration ratio in the metal, the metal purity was 99.999%. The electron beam voltage was 9.7 keV, the power was set at 39.6%, the rate was 0.6 A / s, and the growth temperature was room temperature.

[0052] (3) Growth of β-Ga 2 O 3 nanowires

[0053] The substrate with a 20-nm-thick Au catalytic layer prepared in step (2) was placed in a vacuum chamber, the rotation was turned on, the rotation rate was 5 rpm, the substrate temperature was raised to 600 °C at a heating rate of 10 °C / min, and held for 30 minutes. The purpose of this was to perform in-situ spheroidizing annealing on the Au catalytic layer to turn it into Au nanoparticles. Then the substrate temperature was raised to 700 °C, high-purity argon gas was filled into the chamber for formal deposition, the flow rate was controlled at 32 sccm, the sputtering power was set at 200 W, and the sputtering time was controlled for 300 minutes.

[0054] (4) In-situ annealing treatment of β-Ga 2 O 3 nanowires

[0055] After the sample growth was completed, in-situ annealing was performed at 700 °C for 1 h. The purpose was to allow atoms to obtain sufficient time and energy for diffusion and fusion to obtain a more uniform and dense sample. After the annealing was completed, the temperature was lowered to room temperature at a cooling rate of 10 °C / min, the rotation was turned off, and the sample was taken out.

[0056] Experimental test and analysis:

[0057] In this example, the size of the Au nanoparticles after spheroidizing annealing was 150 nm, and the prepared β-Ga 2 O 3The diameter of the nanowire structure is 150 nm. After growing a Ti / Au composite electrode on this sample, a solar-blind ultraviolet detector is fabricated. The measured dark current is 8.7E-11 A, the photocurrent is 9.6E-6 A, the response rise time is 0.21 s, and the fall time is 0.33 s. Compared with Example 1, the size of the nanowires increases significantly, the performance of the fabricated solar-blind ultraviolet detector is better, the nanostructure is denser, and the influence of grain boundaries and defects is reduced. In order to adapt to the application of solar-blind ultraviolet detectors, high-quality β-Ga 2 O 3 nanowires are fabricated on a single-crystalline (100) Si substrate, which can significantly compensate for the defects of the thin film. These β-Ga 2 O 3 nanowires have the advantages of fewer defects, higher resistivity, and larger optical contact area compared with polycrystalline β-Ga 2 O 3 thin films, and are suitable for fabricating solar-blind ultraviolet detectors.

[0058] Example 3:

[0059] This example is basically the same as Example 1, with the following special features:

[0060] In this example, a 30-nm Au catalytic layer is fabricated on a single-crystalline (100) Si substrate. According to the calculation method of the metal purity based on the impurity concentration ratio of the metal, high-purity Au with a purity of 99.999% is selected as the material for electron beam evaporation. Before sputtering, the Au catalytic layer is subjected to a spheroidizing annealing treatment at 600 °C, and then the temperature is raised to 700 °C for formal sputtering of Ga 2 O 3 . The purity of the Ga 2 O 3 target is 99.99%, and finally in-situ annealing is carried out at 700 °C.

[0061] A method for controllably preparing silicon-based β-Ga 2 O 3 nanowires includes the following steps:

[0062] (1) Substrate cleaning and pretreatment:

[0063] Select a single-crystalline (100) Si substrate with a size of 20 mm × 20 mm and a thickness of 0.5 mm. The substrate is ultrasonically treated in deionized water, acetone, absolute ethanol, and deionized water for 5 min each in sequence, then pickled in a diluted HF solution for 2 min, and finally cleaned in deionized water for 5 min and dried with high-purity nitrogen to obtain a clean and dry substrate. In order to compensate for the change in the substrate surface state caused by the removal of surface oxides during pickling, the cleaned substrate is quickly transferred into a vacuum chamber and treated at a temperature of 300 °C for 30 min to improve the substrate surface state;

[0064] (2) Preparation of Au Catalytic Layer

[0065] Using the electron beam sputtering deposition method, a 30-nm-thick Au catalytic layer is grown on the Si substrate that has undergone surface state treatment in the step (1); the metal used is high-purity Au. According to the calculation method of metal purity based on the impurity concentration ratio of the metal, the metal purity is 99.999%; the electron beam voltage is 9.7 keV, the power is set at 39.6%, the rate is 0.6 A / s, and the growth temperature is room temperature.

[0066] (3) Growth of β-Ga 2 O 3 Nanowires

[0067] Put the substrate with a 30-nm-thick Au catalytic layer prepared in the step (2) into the vacuum chamber, turn on the rotation, the rotation rate is 5 rpm, raise the substrate temperature to 600 °C at a heating rate of 10 °C / min, and keep it warm for 30 min; the purpose is to perform in-situ spheroidizing annealing on the Au catalytic layer to turn it into Au nanoparticles; then raise the substrate temperature to 700 °C, fill the chamber with high-purity argon for formal deposition, the flow rate is controlled at 32 sccm, the sputtering power is set at 200 W, and the sputtering time is controlled for 300 mins.

[0068] (4) In-situ Annealing Treatment of β-Ga 2 O 3 Nanowires

[0069] After the sample growth is completed, perform in-situ annealing at 700 °C for 1 h; the purpose is to allow atoms to obtain sufficient time and energy for diffusion and fusion to obtain a more uniform and dense sample; after the annealing is completed, cool it to room temperature at a cooling rate of 10 °C / min, turn off the rotation, and take out the sample.

[0070] Experimental Test Analysis:

[0071] In this example, the size of the Au nanoparticles after spheroidizing annealing is 200 nm, and the diameter of the prepared β-Ga 2 O 3 nanowire structure is 200 nm. After growing a Ti / Au composite electrode on this sample and fabricating a solar-blind ultraviolet detector, the measured dark current is 1.73E-11 A, the photocurrent is 8.9E-5 A, the response rise time is 0.16 s, and the fall time is 0.27 s. Compared with Example 1, the size of the nanowires has increased significantly, the performance of the fabricated solar-blind ultraviolet detector is better, the nanostructure is more dense, and the influence of grain boundaries and defects is reduced. In order to adapt to the application of solar-blind ultraviolet detectors, the present invention prepares high-quality β-Ga 2 O 3Nanowires can significantly compensate for the defects of thin films. This β-Ga 2 O 3 nanowire, compared with polycrystalline β-Ga 2 O 3 thin film, has the advantages of fewer defects, higher resistivity, and larger optical contact area, and is suitable for fabricating solar-blind ultraviolet detectors.

[0072] Example 4:

[0073] This example is basically the same as Example 1, with the special feature that:

[0074] In this example, a 40-nm Au catalytic layer is prepared on a single-crystalline (100) Si substrate. According to the calculation method of metal purity based on the impurity concentration ratio of the metal, high-purity Au with a purity of 99.999% is selected as the material for electron beam evaporation. Before sputtering, the Au catalytic layer is subjected to spheroidizing annealing treatment at 600 °C, and then the temperature is raised to 700 °C for formal sputtering of Ga 2 O 3 . Ga 2 O 3 . The purity of the Ga

[0075] target is 99.99%, and finally in-situ annealing is carried out at 700 °C. 2 O 3 A method for controllably preparing silicon-based β-Ga

[0076] (1) Substrate cleaning and pretreatment:

[0077] Select a single-crystalline (100) Si substrate with a size of 20 mm × 20 mm and a thickness of 0.5 mm; the substrate is ultrasonically treated in deionized water, acetone, absolute ethanol, and deionized water for 5 minutes each in turn, then pickled in a diluted HF solution for 2 minutes, and finally cleaned in deionized water for 5 minutes and dried with high-purity nitrogen to obtain a clean and dry substrate; in order to make up for the change in the substrate surface state caused by pickling to remove the surface oxide, the cleaned substrate is quickly transferred into a vacuum chamber and treated at a temperature of 300 °C for 30 minutes to improve the substrate surface state;

[0078] (2) Preparation of the Au catalytic layer

[0079] Using the electron beam sputtering deposition method, a 40-nm Au catalytic layer is grown on the Si substrate treated for surface state in step (1); the metal used is high-purity Au, and according to the calculation method of metal purity based on the impurity concentration ratio of the metal, the metal purity is 99.999%; the electron beam voltage is 9.7 keV, the power is set to 39.6%, the rate is 0.6 A / s, and the growth temperature is room temperature;

[0080] (3) β-Ga 2 O 3 Growth of nanowires

[0081] Put the substrate with a 40-nm-thick Au catalytic layer prepared in step (2) into the vacuum chamber, turn on the rotation, with a rotation rate of 5 rpm, raise the substrate temperature to 600 °C at a heating rate of 10 °C / min, and keep it at this temperature for 30 min; the purpose is to spheroidize and anneal the Au catalytic layer in situ to turn it into Au nanoparticles; then raise the substrate temperature to 700 °C, fill the chamber with high-purity argon for formal deposition, control the flow rate at 32 sccm, set the sputtering power at 200 W, and control the sputtering time at 300 mins;

[0082] (4) β-Ga 2 O 3 In-situ annealing treatment of nanowires

[0083] After the sample growth is completed, perform in-situ annealing at 700 °C for 1 h; the purpose is to allow atoms to obtain sufficient time and energy for diffusion and fusion to obtain a more uniform and dense sample; after the annealing is completed, cool it to room temperature at a cooling rate of 10 °C / min, turn off the rotation, and take out the sample.

[0084] Experimental test and analysis:

[0085] In this example, after the spheroidizing annealing, the size distribution of Au nanoparticles is uneven and their sizes are different, and the prepared nanostructures begin to show cluster-like accumulation. The reason for this phenomenon is that the Au catalytic layer is too thick, which affects the growth of the three-dimensional structure of β-Ga 2 O 3 . After growing a Ti / Au composite electrode on this sample, the measured dark current is 9.3E-6 A, and no photocurrent can be measured. Since there are too many internal defects and the compactness of the prepared sample is poor, it is not suitable for fabricating a solar-blind ultraviolet detector.

[0086] All in all, when the thickness of the Au catalytic layer ranges from 10 nm to 30 nm, the diameter of the nanowires shows an increasing trend, and the performance of the prepared solar-blind ultraviolet detector is gradually optimized. When the thickness of the Au catalytic layer is 40 nm, due to the relatively large thickness of the catalytic layer, it hinders the growth of the three-dimensional structure of β-Ga 2 O 3 . Therefore, the thickness of the Au catalytic layer can be controlled within 10 nm to 30 nm to achieve the regulation of the diameter size of β-Ga 2 O 3 nanowires, and then fabricate a high-performance solar-blind ultraviolet detector.

[0087] In summary, in the above embodiments of the present invention, the silicon-based size-controllable β-Ga 2 O 3Preparation process of nanowires, silicon-based size-controllable β-Ga 2 O 3 The preparation process of the nanowires is as follows: First, deposit gold (Au) catalytic layers with different thicknesses on a single-crystal Si(100) substrate, and perform in-situ spheroidizing annealing on the catalytic layers to obtain Au nanoparticles with different sizes. Then, perform magnetron sputtering to grow β-Ga 2 O 3 nanowires and perform in-situ annealing to obtain β-Ga 2 O 3 nanowires with different sizes. Through the above embodiments of the present invention, by regulating the size of β-Ga 2 O 3 nanowires, β-Ga 2 O 3 nanowires with the advantages of few defects, high resistivity, uniform density, etc. can be obtained. The β-Ga 2 O 3 nanowires with different sizes prepared by the present invention exhibit excellent performance in the application of solar-blind ultraviolet detectors, and can be applied to missile approach warning systems, ultraviolet communication, ultraviolet imaging navigation, etc. in the military field, and have broad application prospects in aspects such as automotive exhaust detection, flame detection, and fingerprint detection in the civilian field.

[0088] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments, and various changes can be made according to the purpose of the invention of the present invention. Any changes, modifications, substitutions, combinations, or simplifications made based on the spirit and principle of the technical solution of the present invention shall be equivalent replacement methods. As long as they meet the invention purpose of the present invention and do not deviate from the technical principle and inventive concept of the preparation method adopted by the present invention, they all belong to the protection scope of the present invention.

Claims

1. A method for preparing silicon-based size-controllable β-Ga 2 O 3 nanowires It is characterized in that It includes the following steps: (1) Preparation of the Au catalytic layer: Using the electron beam sputtering deposition method, a Au catalytic layer with a thickness of 10 - 40 nm is grown on a cleaned and surface-state-treated single crystal (100) Si substrate, and the size of β-Ga 2 O 3 nanowires is regulated by controlling the thickness of the catalytic layer; the Au used is high-purity Au, and according to the calculation method of metal purity based on the impurity concentration ratio contained in the metal, the metal purity is 99 - 99.99999%; (2)β-Ga 2 O 3 Growth process of nanowires: Using the magnetron sputtering method, grow β-Ga 2 O 3 nanowires on the substrate with an Au catalytic layer prepared in the step (1); select Ga 2 O 3 target material with a purity of not less than 99.99%; before formal sputtering, pre-treat the Au catalytic layer at a temperature not less than 600 °C for at least 30 mins to perform in-situ spheroidizing annealing on the Au catalytic layer to make it into Au nanoparticles; then carry out formal sputtering, continue to raise the substrate temperature to not less than 700 °C, and introduce Ar gas to generate a glow plasma, thereby preparing β-Ga 2 O 3 nanowires; (3)β-Ga 2 O 3 In-situ annealing treatment of nanowires: Subject the β-Ga 2 O 3 nanowires prepared in the step (2) to in-situ annealing treatment at an annealing temperature of not less than 700 °C, so as to obtain β-Ga 2 O 3 nanowires with a uniform and dense structure. After the annealing is completed, wait for the sample to cool to room temperature, and then take out the finished silicon-based β-Ga 2 O 3 nanowire product.

2. The preparation method of silicon-based size-controllable β-Ga 2 O 3 nanowires It is characterized in that: In the step (1), an Au catalytic layer is grown on a substrate by an electron beam sputtering deposition method.

3. The preparation method of silicon-based size-controllable β-Ga 2 O 3 nanowires It is characterized in that: In the step (1), the thickness of the Au catalytic layer prepared on the substrate is 10-30 nm.

4. The preparation method of silicon-based size-controllable β-Ga 2 O 3 nanowires It is characterized in that: In the step (1), after pickling the single crystal (100)Si substrate, it is pretreated at no less than 300 °C for at least 30 minutes to obtain a clean and dry substrate surface state.

5. The preparation method of silicon-based size-controllable β-Ga 2 O 3 nanowires It is characterized in that: In the step (1), when pickling the single-crystal (100) Si substrate, calculated by volume ratio, a solution with a ratio of HF:H 2 O of 1:9 is used for pickling to remove the oxide on the surface of the Si substrate.

6. The method for preparing silicon-based size-controllable β-Ga 2 O 3 nanowires, It is characterized in that: In the step (2), a preparation method of radio frequency magnetron is adopted, and the background vacuum of the sputtering cavity is controlled to be not higher than 10 -7 Torr, the sputtering gas pressure is not higher than 10 -3 Torr, the sputtering power is not lower than 200W, and the sputtering time is at least 300 mins.

7. The preparation method of silicon-based size-controllable β-Ga 2 O 3 nanowires, It is characterized in that: In the step (2), the argon is high-purity argon with a purity of no less than 99.999%, and the flow rate is at least 32 sccm.

8. The preparation method of silicon-based size-controllable β-Ga 2 O 3 nanowires, It is characterized in that: In the step (3), the annealing time is at least 1 h.

9. The method for preparing silicon-based size-controllable β-Ga 2 O 3 nanowires, It is characterized in that: In the step (2), in-situ spheroidizing annealing is carried out on the Au catalytic layer, and the width size of the Au nanoparticles after spheroidizing annealing is 100 - 200 nm; then in the step (3), the β-Ga 2 O 3 nanowire finished product of β-Ga 2 O 3 nanowire structure has a diameter of 100 - 200 nm.

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