Self-driven ultraviolet detector and preparation method thereof

Abstract

The invention relates to the technical field of semiconductor photoelectric detectors, in particular to a self-driven ultraviolet detector and a preparation method thereof, and the self-driven ultraviolet detector sequentially comprises a substrate, a BaTiO3 layer and a ZnO layer from bottom to top; the BaTiO3 layer is provided with a first electrode, and the ZnO layer is provided with a second electrode; the ZnO layer comprises a plurality of ZnO cylinders arranged in a cylindrical array, and each ZnO cylinder is independently provided with a second electrode; the first electrode is Al, and the second electrode is Au or Pt; the self-driven ultraviolet detector provided by the invention can work under 0 V bias voltage, namely a self-driven working mode; the device can also work under other non-zero bias voltage, and the bias voltage range is-50V to 50V; and high responsivity can be obtained under the working condition of 0 V.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor photoelectric detectors, and in particular to a self-driven ultraviolet detector and a preparation method thereof. Background Art

[0002] UV detectors are widely used in astronomy, combustion engineering, water purification, flame detection, biological effects, space communications, and environmental pollution monitoring. To date, photomultiplier tubes and Si-based UV-enhanced avalanche detectors have long occupied the main body of the UV detector market. They have mature processes and relatively excellent performance. However, photomultiplier tubes usually require extremely high operating voltages, are huge in size, and are easily disturbed by magnetic fields. Since Si-based UV-enhanced avalanche detectors respond to visible light, they need to be equipped with expensive filters to eliminate this effect when working as UV detectors, and usually have to work in a low-temperature environment to obtain high sensitivity.

[0003] At present, the demand for ultraviolet photodetectors with low energy consumption and high response speed is becoming more and more urgent. In this context, self-driven photodetectors that can work without external power supply have become an important research and development direction. The most common way to achieve self-driven photodetection is to separate photogenerated electron-hole pairs using the built-in electric field formed by PN (or PIN) junction or Schottky junction. However, these methods still face problems such as difficult preparation and poor performance.

[0004] In recent years, ferroelectric materials, such as barium titanate (BaTiO3) and strontium titanate (SrTiO3), have attracted more and more attention from researchers in the field of photoelectric conversion and photovoltaic technology due to their unique ferroelectric spontaneous polarization characteristics. Introducing ferroelectric materials and their spontaneous polarization effects into wide-bandgap semiconductor Schottky junction self-driven ultraviolet detectors can undoubtedly enhance the built-in electric field and thus improve the photoelectric performance of the device; however, the use of ferroelectric materials alone results in very poor device performance and low responsiveness; and currently, it is difficult to obtain high-quality materials when growing materials that are highly responsive to ultraviolet light on ferroelectric materials, and the device performance is also low. Summary of the invention

[0005] In view of this, the present invention aims to provide a self-driven ultraviolet detector and a preparation method thereof, so as to solve the technical problems of low responsiveness and poor performance of the self-driven ultraviolet detector in the prior art.

[0006] To achieve the above object, the technical solution created by the present invention is implemented as follows: A self-driven ultraviolet detector, comprising a substrate, a BaTiO3 layer and a ZnO layer from bottom to top; the BaTiO3 layer is provided with a first electrode, and the ZnO layer is provided with a second electrode; the ZnO layer comprises a plurality of ZnO cylinders arranged in a cylinder array, and each of the ZnO cylinders is independently provided with the second electrode; The first electrode is Al, and the second electrode is Au or Pt.

[0007] Furthermore, the substrate is sapphire or Si; the thickness of the first electrode is greater than 20 nm and less than 100 nm; the thickness of the second electrode is greater than 20 nm and less than 100 nm.

[0008] Furthermore, the second electrode is a circular structure, a grid structure, or a single-finger structure.

[0009] Furthermore, the diameter of the ZnO cylinder ranges from 0.1 mm to 5 mm; the thickness of the ZnO cylinder ranges from 100 nm to 500 nm.

[0010] Furthermore, the distance between the first electrode and each of the second electrodes is 2 μm to 5 μm.

[0011] The present invention also provides a method for preparing the self-driven ultraviolet detector, which comprises the following steps: S1. The substrate is placed in a magnetron sputtering device, and radio frequency magnetron sputtering is performed at a temperature of 420°C to 650°C using a BaTiO3 ceramic target; the growth time of the radio frequency magnetron sputtering is 0.5h to 3h; post-annealing is performed at a temperature of 700°C to 900°C; the post-annealing time is 10min to 1h; S2. After the substrate with the grown BaTiO3 layer is cleaned, it is placed in a molecular beam epitaxy device to grow a ZnO film; S3. Etching the ZnO film into a plurality of ZnO cylinders by photolithography and etching; S4. Prepare the first electrode on the surface of the BaTiO3 layer, and prepare the second electrode on the surface of the ZnO cylinder to obtain the self-driven ultraviolet detector.

[0012] Furthermore, the substrate is first cleaned with trichloroethylene, acetone, and ethanol respectively, and then dried with nitrogen; the cleaning of the substrate on which the BaTiO3 layer has been grown includes cleaning with oxygen plasma, the cleaning power is 60W to 100W, and the cleaning time is 1min to 20min; the etching agent is hydrochloric acid with a concentration of 0.01mol / L to 0.1mol / L.

[0013] Furthermore, the working gas in the RF magnetron sputtering process is argon gas, and the flow rate of the argon gas is 5 sccm to 30 sccm; the sputtering pressure is 0.5 Pa to 1 Pa, and the sputtering power is 55 W to 80 W.

[0014] Furthermore, the process of growing the ZnO thin film includes: S21. Control the temperature of the substrate to 750°C to 850°C, the magnesium source temperature to 400°C to 600°C, the oxygen flow rate to 0.3sccm to 2sccm, the RF power to 200W to 300W, the growth time to 5min to 30min, and grow a MgO buffer layer; S22. Control the temperature of the substrate to 880°C to 980°C, the temperature of the zinc source to 400°C to 600°C, the oxygen flow rate to 0.3sccm to 2sccm, the RF power to 200W to 300W, the growth time to 2h to 5h, and grow a ZnO thin film.

[0015] Furthermore, the preferred orientation of the BaTiO3 layer is controlled by controlling the post-annealing conditions, and the preferred orientation includes no orientation, (111) orientation, and (001) orientation.

[0016] Compared with the prior art, the invention can achieve the following beneficial effects: The self-driven ultraviolet detector provided by the present invention can work under 0 V bias voltage, that is, self-driven working mode; it can also work under other non-zero bias voltages, and the bias voltage range is -50V to 50V; and high responsiveness can be obtained under 0 V working conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments and descriptions of the present invention are used to explain the present invention and do not constitute an improper limitation on the present invention. In the drawings: Figure 1 A schematic flow chart of a method for preparing a self-driven ultraviolet detector according to Example 1 of the present invention; Figure 2 The XRD spectrum of the BaTiO3 layer of the self-driven ultraviolet detector described in Example 1 of the present invention; Figure 3 AFM test result diagram of the BaTiO3 layer of the self-driven ultraviolet detector described in Example 1 of the present invention; Figure 4 The light response curve of the self-driven ultraviolet detector described in Example 1 of the present invention at 0V is shown; Figure 5 The response time curve of the self-driven ultraviolet detector described in Example 1 of the present invention at 0V is provided; Figure 6 The light response curve of the self-driven ultraviolet detector described in Example 1 of the present invention at 10V is shown; Figure 7 This is a graph showing the ultraviolet-visible transmission of the ZnO film in the self-driven ultraviolet detector described in Example 1 of the present invention. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the invention more clear, the invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the invention and do not constitute a limitation of the invention.

[0019] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0020] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0021] In the description of the invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0022] In a specific embodiment of the present invention, a self-driven ultraviolet detector is provided, which includes a substrate, a BaTiO3 layer and a ZnO layer from bottom to top; the BaTiO3 layer is provided with a first electrode, and the ZnO layer is provided with a second electrode; the ZnO layer includes a plurality of ZnO cylinders arranged in a cylinder array, and each ZnO cylinder is independently provided with the second electrode; the first electrode is Al, and the second electrode is Au or Pt. Specifically, the plurality of ZnO cylinders are evenly distributed and perpendicular to the entire BaTiO3 layer; the plurality of ZnO cylinders arranged in a cylinder array can be 1 1~20 20; In a more preferred embodiment, the number of ZnO cylinders ranges from 5 5~20 20, each ZnO cylinder is an independent detector unit.

[0023] In a specific embodiment, the substrate is sapphire or Si; the thickness of the first electrode is greater than 20nm and less than 100nm; the thickness of the second electrode is greater than 20nm and less than 100nm. The second electrode can be a circular structure, a grid structure, or a single interdigital structure; the spacing between the first electrode and each of the second electrodes is 2μm to 5μm. The diameter of the ZnO cylinder ranges from 0.1mm to 5mm; the thickness of the ZnO cylinder ranges from 100nm to 500nm; cylinder spacing-cylinder diameter = 0.1mm~10mm; it can better avoid interference related to each cylinder, and facilitate preparation and testing.

[0024] The self-driven ultraviolet detector provided in the specific embodiment of the present invention can work under 0 V bias, that is, self-driven working mode; it can also work under other non-zero bias, the bias range is -50V to 50V; and high responsivity can be obtained under 0 V working conditions.

[0025] A specific embodiment of the present invention further provides a method for preparing the self-driven ultraviolet detector, the method comprising the steps of: S1. Place the substrate in a magnetron sputtering device, and use a BaTiO3 ceramic target to perform radio frequency magnetron sputtering at a temperature of 420°C to 650°C; the working gas in the radio frequency magnetron sputtering process is argon, and the flow rate of the argon is 5sccm to 30sccm; the sputtering pressure is 0.5Pa to 1Pa, and the sputtering power is 55W to 80W; the growth time of radio frequency magnetron sputtering is 0.5h to 3h; post-annealing is performed at a temperature of 700°C to 900°C; the time of the post-annealing is 10min to 1h; the preferred orientation of the BaTiO3 layer is controlled by controlling the conditions of the post-annealing, and the annealing conditions specifically include the annealing temperature and time; the preferred orientation includes no orientation, (111) orientation, and (001) orientation; in a preferred embodiment, the substrate is first cleaned with trichloroethylene, acetone, and ethanol respectively, then blown dry with nitrogen, and then placed in the magnetron sputtering device; S2. The substrate on which the BaTiO3 layer is grown is cleaned and placed in a molecular beam epitaxy device to grow a ZnO film; the substrate on which the BaTiO3 layer is grown is cleaned by oxygen plasma cleaning, the cleaning power is 60W to 100W, and the cleaning time is 1min to 20min; the process of growing the ZnO film comprises: S21. Control the temperature of the substrate to be 750°C to 850°C, the temperature of the magnesium source to be 400°C to 600°C, the oxygen flow rate to be 0.3sccm to 2sccm, the RF power to be 200W to 300W, the growth time to be 5min to 30min, and grow a MgO buffer layer; by growing the MgO buffer layer, it is more conducive to growing a high-quality ZnO layer on the BaTiO3 layer, which can effectively improve the enhancement effect of the ZnO device; effectively solve the technical problem that it is difficult to obtain a high-quality ZnO film by growing ZnO on BaTiO3, and it is also difficult to achieve a high-performance detector; S22. Control the temperature of the substrate to 880°C to 980°C, the temperature of the zinc source to 400°C to 600°C, the oxygen flow rate to 0.3sccm to 2sccm, the RF power to 200W to 300W, the growth time to 2h to 5h, and grow a ZnO thin film.

[0026] S3. Etch the ZnO film into several ZnO cylinders by photolithography and etching; the etching agent is hydrochloric acid with a concentration of 0.01mol / L to 0.1mol / L; specifically, the photolithography step may include: first apply photoresist, then cover some areas with a photomask with a pattern, then irradiate with ultraviolet light, and then soak with developer, at this time, a part of the photoresist area is not irradiated with ultraviolet light because of the pattern cover in the photomask, and this part of the area will react with the developer and appear hollow. After the photoresist is hollowed out, the ZnO layer below will be exposed; at this time, the ZnO is etched again, and the ZnO below the hollowed area can be etched away to obtain several ZnO cylinders.

[0027] S4. The first electrode is prepared on the surface of the BaTiO3 layer outside the ZnO cylinder, and the second electrode is prepared on the surface of the ZnO cylinder to obtain the self-driven ultraviolet detector; specifically, the electrodes can be prepared by alignment photolithography and metal deposition, for example, using negative photoresist and lift-off process, and observing under a microscope to align the electrode pattern with the cylinder pattern.

[0028] Through the preparation method of the specific embodiment of the present invention, it can be ensured that the size of each ZnO cylinder is uniform, the intervals are the same, and they are arranged vertically; thereby, it can be ensured that the performance of each detector unit is substantially the same.

[0029] The present invention is further described in detail below in conjunction with embodiments, but this description does not constitute a limitation of the present invention.

[0030] Example 1 like Figure 1 FIG. 1 is a flow chart of a method for preparing a self-driven ultraviolet detector according to an embodiment of the present invention. As can be seen from the figure, the method for preparing a self-driven ultraviolet detector according to the embodiment of the present invention comprises the following steps: (1) Use trichloroethylene, acetone, and ethanol to clean the sapphire substrate respectively, and then blow it dry with dry nitrogen.

[0031] (2) Place the substrate in step (1) in a magnetron sputtering device and perform radio frequency magnetron sputtering at 500 degrees using a BaTiO3 ceramic target. Select argon as the working gas, the gas flow rate is 20 sccm, the sputtering pressure is 2 Pa, the sputtering power is 60 W, and the growth time is 2 h. Then, post-annealing is performed at 800 degrees for 0.5 h.

[0032] (3) The surface of the substrate on which BaTiO3 was grown in step (2) was cleaned using oxygen plasma. The cleaning conditions were: power 80 W, time 10 min.

[0033] (4) The cleaned BaTiO3 in step (3) was placed in a molecular beam epitaxy (MBE) device, and the substrate temperature was first controlled to be 800 degrees, the magnesium source temperature was 450 degrees, the oxygen flow rate was 1 sccm, the RF power was 250 W, and the growth time was 10 minutes to grow a MgO buffer layer. Then, the substrate temperature was controlled to be 950 degrees, the zinc source temperature was 500 degrees, the oxygen flow rate was 1 sccm, the RF power was 250 W, and the growth time was 3 hours to grow a ZnO film.

[0034] (5) The thin film obtained in step (4) is subjected to photolithography and etching to etch the ZnO layer into independent cylinders with a diameter of 2 mm. The etching reagent is 0.05 mol / L dilute hydrochloric acid.

[0035] (6) The thin film obtained in step (5) is subjected to alignment photolithography and metal deposition to prepare an electrode on the surface of the ZnO layer; another electrode is prepared on the surface of the BaTiO3 layer outside the ZnO cylinder, and finally a self-driven ultraviolet detector is obtained. The electrode material on the ZnO surface is Au and the shape is circular, and the electrode material on the BaTiO3 surface is Al, and the distance between the electrode on the BaTiO3 surface and the ZnO cylinder is 2 microns.

[0036] Finally, a self-driven UV detector with Au / ZnO / BaTiO3 / Al structure was obtained. The XRD spectrum of the prepared BaTiO3 layer is shown in Figure 2 As shown in the figure, it can be seen that the BaTiO3 layer is (001) oriented; the AFM test results of the BaTiO3 layer are as follows Figure 3 As shown in the figure, it can be seen that the surface roughness of the BaTiO3 layer is 1.64 nm.

[0037] The response curve of the self-driven UV detector under 0 V conditions is shown in Figure 4 As shown in the figure, it can be seen that the responsivity of the self-driven UV detector of this embodiment can reach 258 mA / W, and the UV-visible suppression ratio is 1.36. 10 5 .

[0038] Under 0 V conditions, the response time spectrum of the self-driven UV detector is as follows: Figure 5 As shown in the figure, it can be seen that the rise time of the self-driven UV detector is 10 ns and the fall time is 20 ns.

[0039] The response curve of the self-driven UV detector under 10 V conditions is shown in Figure 6 As shown in the figure, it can be seen that the responsivity of the self-driven UV detector can reach 133 amperes / watt (A / W) and the UV-visible suppression ratio is 1.03 107 .

[0040] In order to test the optical and electrical properties of the ZnO layer, the same ZnO growth conditions were used to grow it on a sapphire substrate, and UV-visible transmission spectra and Hall tests were performed. Figure 7 As shown in the figure, it can be seen that the transmittance of ZnO film in the visible region is excellent, higher than 95%; there is a steep absorption cutoff edge near 370nm~380nm; through the Hall test, the intrinsic carrier concentration of ZnO is 9.1 10 15 cm -3 .

[0041] Example 2 In order to compare the effect of the electrode on the ZnO surface on the device, this example only changes the electrode on the ZnO surface to Pt, and the other conditions are exactly the same as in Example 1. A device with a Pt / ZnO / BaTiO3 / Al structure is prepared. Under 0 V conditions, the responsivity of the self-driven UV detector can reach 209 mA / W, and the UV-visible suppression ratio is 1.1 10 5 , the rise time of the self-driven UV detector is 10 ns, and the fall time is 20 ns. It can be seen that compared with the self-driven UV detector using Au electrodes, the responsivity of the device in this embodiment is slightly lower, and the response time remains unchanged.

[0042] Example 3 In order to compare the effect of substrate material on the self-driven UV detector, this example only changes the substrate material used to Si, and the other conditions are exactly the same as in Example 1. A self-driven UV detector with Au / ZnO / BaTiO3 / Al (substrate Si) structure is prepared. Under 0 V conditions, the responsivity of the self-driven UV detector can reach 266 mA / W, and the UV-visible suppression ratio is 1.2 10 4 The rise time of the device is 10ns, and the fall time is 20ns. It can be seen that compared with the device with sapphire substrate, the responsivity of the self-driven UV detector in this embodiment is slightly higher, but the UV-visible suppression ratio is significantly reduced, and the response time remains unchanged.

[0043] Example 4 In order to compare the effect of the MgO buffer layer on the performance of the self-driven UV detector during the preparation of the ZnO layer, this embodiment only changes the growth time of the MgO buffer layer during the preparation of the ZnO layer, with a total of 5 groups, namely 0, 1, 5, 20, and 30 min, and the other conditions are exactly the same as in Example 1. Under 0 V conditions, the responsivity of the self-driven UV detector can reach 50, 120, 251, 190, and 60 mA / W, respectively, and the UV-visible suppression ratio is 4.1 10 4 , 8.9 10 4 , 1.3 10 5 , 1.9 10 5 , 9.1 10 4 The rise time of the self-driven UV detector is 10 ns, and the fall time is 20 ns. It can be seen that if the MgO buffer layer is not grown or the growth time is too long, the device's responsivity and suppression ratio will be significantly reduced.

[0044] Example 5 In order to compare the effect of BaTiO3 annealing conditions on the performance of the self-driven ultraviolet detector, this embodiment only changes the BaTiO3 annealing conditions, and the other conditions are exactly the same as in Example 1. The BaTiO3 annealing conditions are: no annealing; 700 degrees for 0.5 hours; 700 degrees for 1 hour; 800 degrees for 1 hour; 900 degrees for 0.5 hours; 900 degrees for 1 hour, a total of 6 groups. The resulting BaTiO3 crystal phases are: amorphous (no annealing); (001) orientation (700 degrees for 0.5 hours); (001) orientation (700 degrees for 1 hour); (001) orientation (800 degrees for 1 hour); (111) orientation (900 degrees for 0.5 hours); (001) orientation (900 degrees for 1 hour). Under 0 V conditions, the responsivities of the self-driven ultraviolet detector are 230, 255, 256, 259, 251, and 202 mA / W, respectively, and the ultraviolet-visible suppression ratio is 8.8 10 4 , 1.1 10 5 , 1.2 10 5 , 1.2 10 5 , 1.0 10 5 , 7.0 10 4 The rise time of the self-driven UV detector is 10 ns, and the fall time is 20 ns. It can be seen that the performance of the self-driven UV detector is best when the orientation of the BaTiO3 layer is (001).

[0045] The above specific implementations do not constitute a limitation on the protection scope of the present invention. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent substitution and improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A self-driven ultraviolet detector, characterized in that: The self-driven ultraviolet detector includes a substrate, a BaTiO3 layer and a ZnO layer from bottom to top; the BaTiO3 layer is provided with a first electrode, and the ZnO layer is provided with a second electrode; the ZnO layer includes a plurality of ZnO cylinders arranged in a cylinder array, and each of the ZnO cylinders is independently provided with the second electrode; The first electrode is Al, and the second electrode is Au or Pt.

2. The self-driven ultraviolet detector according to claim 1, characterized in that: The substrate is sapphire or Si; the thickness of the first electrode is greater than 20 nm and less than 100 nm; the thickness of the second electrode is greater than 20 nm and less than 100 nm.

3. The self-driven ultraviolet detector according to claim 1, characterized in that: The second electrode is a circular structure, a grid structure, or a single-finger structure.

4. The self-driven ultraviolet detector according to claim 1, characterized in that: The diameter of the ZnO cylinder ranges from 0.1 mm to 5 mm; the thickness of the ZnO cylinder ranges from 100 nm to 500 nm.

5. The self-driven ultraviolet detector according to claim 1, characterized in that: The distance between the first electrode and each of the second electrodes is 2 μm to 5 μm.

6. A method for preparing a self-driven ultraviolet detector according to any one of claims 1 to 5, characterized in that: The preparation method comprises the steps of: S1. placing the substrate in a magnetron sputtering device, and performing radio frequency magnetron sputtering at a temperature of 420°C to 650°C using a BaTiO3 ceramic target; the growth time of the radio frequency magnetron sputtering is 0.5 h to 3 h; post-annealing is performed at a temperature of 700°C to 900°C; the post-annealing time is 10 min to 1 h; S2. After the substrate with the grown BaTiO3 layer is cleaned, it is placed in a molecular beam epitaxy device to grow a ZnO film; S3. Etching the ZnO film into a plurality of ZnO cylinders by photolithography and etching; S4. Prepare the first electrode on the surface of the BaTiO3 layer, and prepare the second electrode on the surface of the ZnO cylinder to obtain the self-driven ultraviolet detector.

7. The method for preparing the self-driven ultraviolet detector according to claim 6, characterized in that: The substrate is first cleaned with trichloroethylene, acetone and ethanol respectively, and then dried with nitrogen; the substrate cleaning on which the BaTiO3 layer is grown includes cleaning with oxygen plasma, the cleaning power is 60W to 100W, and the cleaning time is 1min to 20min; the etching agent is hydrochloric acid with a concentration of 0.01mol / L to 0.1mol / L.

8. The method for preparing the self-driven ultraviolet detector according to claim 6, characterized in that: The working gas in the RF magnetron sputtering process is argon gas, and the flow rate of the argon gas is 5 sccm to 30 sccm; the sputtering pressure is 0.5 Pa to 1 Pa, and the sputtering power is 55 W to 80 W.

9. The method for preparing the self-driven ultraviolet detector according to claim 6, characterized in that: The process of growing the ZnO thin film comprises: S21. Control the temperature of the substrate to 750°C to 850°C, the magnesium source temperature to 400°C to 600°C, the oxygen flow rate to 0.3sccm to 2sccm, the RF power to 200W to 300W, the growth time to 5min to 30min, and grow a MgO buffer layer; S22. Control the temperature of the substrate to 880°C to 980°C, the temperature of the zinc source to 400°C to 600°C, the oxygen flow rate to 0.3sccm to 2sccm, the RF power to 200W to 300W, the growth time to 2h to 5h, and grow a ZnO thin film.

10. The method for preparing the self-driven ultraviolet detector according to claim 6, characterized in that: The preferred orientation of the BaTiO3 layer is controlled by controlling the post-annealing conditions, and the preferred orientation includes no orientation, (111) orientation, and (001) orientation.

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