NdZnO-based high-inhibition-ratio self-powered day-blind ultraviolet photodetector and preparation method thereof

Abstract

The application belongs to the technical field of wide band gap semiconductor photoelectric detection, and particularly relates to a NdZnO-based high-suppression-ratio self-powered solar-blind ultraviolet photodetector and a preparation method thereof, realizes accurate band regulation of Nd2O3, red shifts the absorption cutoff edge from 215 nm to 280 nm, and perfectly matches the solar-blind ultraviolet band. Meanwhile, a p-Gr / i-NdZnO / n-Si double heterojunction structure forms two directionally coordinated built-in electric fields, and the photo-generated carriers can be separated and collected quickly without external bias, effectively solving the problem of excessively high resistivity of Nd2O3, and realizing self-powered work under 0V bias. The preparation method adopts room-temperature magnetron co-sputtering and graphene wet transfer process, and the whole preparation process is completed at room temperature, without complex high-temperature equipment, and the process parameters are controllable and good in repeatability, and the method is suitable for large-scale industrial production.

Description

Technical Field

[0001] This invention belongs to the field of wide bandgap semiconductor photoelectric detection technology, specifically relating to an NdZnO-based high suppression ratio self-powered solar-blind ultraviolet photodetector and its preparation method, which is suitable for solar-blind ultraviolet (200-280nm) detection scenarios such as ultraviolet communication, fire monitoring, high voltage corona detection, and biochemical detection. Background Technology

[0002] Solar-blind ultraviolet photodetectors have become a research hotspot in the field of photoelectric detection due to their advantages such as strong resistance to natural light interference, low false alarm rate, and ability to operate with low power consumption or even self-powered operation. They are widely used in military security, industrial monitoring, and civilian optoelectronics. The core of high-performance solar-blind ultraviolet detectors is a wide-bandgap photosensitive material matched to the solar-blind band. Rare earth oxide Nd₂O₃, with its ultra-high intrinsic bandgap (5.75 eV), high dielectric constant, and excellent thermal and chemical stability, is a highly promising candidate material for solar-blind detection.

[0003] However, in existing technologies, Nd2O3 suffers from the following key technical defects in solar-blind ultraviolet detection applications, which severely limit its practical application: 1. The band gap is too wide and the absorption band is mismatched: The intrinsic absorption cutoff edge of Nd2O3 is only 215nm, which is much shorter than the ideal cutoff edge of 280nm for solar-blind detection. It cannot cover the complete solar-blind ultraviolet band and causes a lot of energy loss. 2. High resistivity and poor carrier transport performance: The high internal resistance of Nd2O3 makes it difficult for photogenerated carriers to be effectively separated and transported, resulting in low photocurrent and limited detection performance. 3. Insufficient device structure design: Traditional Nd2O3-based detectors have not achieved an efficient carrier separation structure and cannot achieve self-powered operation under 0V bias, which limits their application in low-power, miniaturized integrated systems; 4. Low spectral suppression ratio: Existing rare earth oxide-based solar blind detectors have insufficient ultraviolet / visible light suppression ratios, are easily affected by natural light, and have poor adaptability to actual environments.

[0004] Currently, existing technologies have not yet achieved precise bandgap control of Nd2O3 to obtain an ideal absorption cutoff edge of 280nm, nor have there been any reports on constructing a dual heterojunction self-powered solar-blind ultraviolet detector by combining Zn-doped modified NdZnO with graphene and n-type Si. There is an urgent need for a Nd2O3-based solar-blind ultraviolet detector and its preparation method that can solve the above technical problems. Summary of the Invention

[0005] In view of this, the purpose of this invention is to provide a self-powered solar-blind ultraviolet photodetector with high suppression ratio based on NdZnO and its preparation method, so as to solve the technical problems involved in the background art.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A high-suppression-ratio, self-powered, solar-blind ultraviolet photodetector based on NdZnO, is a vertically layered double heterojunction structure, comprising, from top to bottom: p-type graphene top electrode layer; Intrinsic NdZnO light-absorbing layer; n-type Si substrate; The intrinsic NdZnO light-absorbing layer is an amorphous thin film of Zn-doped Nd2O3 with a band gap of 4.43 eV and a light absorption cutoff edge of 280 nm. A first heterojunction is formed between the p-type graphene top electrode layer and the intrinsic NdZnO light-absorbing layer, and a second heterojunction is formed between the intrinsic NdZnO light-absorbing layer and the n-type Si substrate, forming a p-Gr / i-NdZnO / n-Si dual built-in electric field heterojunction, which is used to realize self-powered solar-blind ultraviolet detection under 0V bias.

[0007] Furthermore, the thickness of the Zn-doped Nd2O3 amorphous thin film ranges from 190 to 200 nm.

[0008] Furthermore, the thickness of the Zn-doped Nd2O3 amorphous thin film is 196 nm.

[0009] Furthermore, the detector exhibits a dark current of 1.44 × 10⁻⁶ under 0V bias and 255nm solar-blind ultraviolet illumination. - ¹¹A, UV / Vis suppression ratio R 255nm / R 532nm ≥7.1×10³.

[0010] Furthermore, a Ti / Au composite electrode is disposed on the surface of the p-type graphene top electrode layer, and an In electrode is disposed on the back side of the n-type Si substrate.

[0011] A method for fabricating an NdZnO-based high-suppression-ratio self-powered solar-blind ultraviolet photodetector includes the following steps: Step 1: Clean the n-type Si substrate; Step 2: Using room temperature magnetron co-sputtering, with Nd2O3 ceramic target and Zn metal target as sputtering sources, an amorphous thin film of Zn-doped Nd2O3 is deposited on the cleaned n-type Si substrate to obtain the i-NdZnO / n-Si structure. Step 3: Transfer graphene onto the surface of the Zn-doped Nd2O3 amorphous thin film to obtain a p-Gr / i-NdZnO / n-Si double heterojunction structure; Step 4: Prepare a top electrode on the surface of the p-type graphene top electrode layer and prepare a bottom electrode on the back side of the n-type Si substrate to obtain the detector.

[0012] Furthermore, the process parameters for magnetron co-sputtering described in step 2 are as follows: The sputtering atmosphere was a room temperature oxygen-free doping environment. The Nd2O3 target power was 80W, the Zn target power was 60W, and the sputtering time was 20min, resulting in a Zn-doped Nd2O3 amorphous thin film with a band gap of 4.43eV and an absorption cutoff edge of 280nm.

[0013] Furthermore, the graphene transfer described in step 3 specifically involves: The PMMA / Gr / Cu composite film was immersed in an etching solution to remove the Cu substrate. After cleaning, it was transferred to the surface of the Zn-doped Nd2O3 amorphous thin film. Then, the PMMA was removed to obtain a p-Gr / i-NdZnO / n-Si double heterojunction structure.

[0014] Furthermore, the corrosive solution is an ammonium persulfate solution with a concentration of 0.1 mol / L and a corrosion time of 12 h.

[0015] Furthermore, the top electrode in step 4 is a Ti / Au composite electrode, prepared by vacuum thermal evaporation, wherein the Ti layer thickness is 50 nm and the Au layer thickness is 200 nm; the bottom electrode is an In electrode, prepared by welding.

[0016] The beneficial effects of this invention are: Through the above technical solution, this invention achieves precise bandgap modulation of Nd₂O₃ for the first time, redshifting the absorption cutoff edge from 215nm to 280nm, perfectly matching the solar-blind ultraviolet band. Simultaneously, the p-Gr / i-NdZnO / n-Si double heterojunction structure forms two synergistic built-in electric fields (E1: n-Si→i-NdZnO; E2: i-NdZnO→p-Gr), enabling rapid separation and collection of photogenerated carriers without external bias, effectively solving the problem of excessively high resistivity in Nd₂O₃ and achieving self-powered operation under 0V bias. This preparation method employs room-temperature magnetron co-sputtering and graphene wet transfer processes. The entire preparation process is completed at room temperature, eliminating the need for complex high-temperature equipment. The process parameters are controllable and highly repeatable, making it suitable for large-scale industrial production. Attached Figure Description

[0017] Figure 1 The diagram shows a structural schematic of a self-powered solar-blind ultraviolet photodetector with high suppression ratio based on NdZnO. Figure 2 The diagram shows a step-by-step flowchart of a method for fabricating a self-powered solar-blind ultraviolet photodetector with high suppression ratio based on NdZnO. Figure 3 The diagram shows a room-temperature magnetron co-sputtering process for preparing NdZnO thin films. Figure 4 The figure shows the bandgap variation curves of NdZnO thin films with different Zn atom contents. Figure 5 The image shows the light absorption curve of an NdZnO thin film with a band gap of 4.43 eV. Figure 6 The image shown is a cross-sectional SEM image of the NdZnO / n-Si structure. Figure 7 The image shows the surface SEM image of the NdZnO thin film and the surface distribution diagram of Nd, Zn, and O elements. Figure 8 The image shown is the XPS full spectrum of the NdZnO thin film; Figure 9 The figure shows the dark current IV curve of the p-Gr / i-NdZnO / n-Si detector. Figure 10 The figure shows the IV curves of the detector under different optical power densities. Figure 11 The figure shows the power-law fitting curve of photocurrent versus optical power density under a 0V bias voltage. Figure 12 The figure shows the responsivity and detectivity curves under different optical power densities at a bias voltage of 0V. Figure 13 The figure shows the It transient response curves for different optical power densities under a 0V bias voltage; Figure 14 The figure shows an amplified curve of the single-cycle transient response at an optical power density of 125.4 μW / cm². Figure 15 The figure shows the statistical curves of response time under different optical power densities; Figure 16 The figure shows the IV curves of different wavelengths of light under 0V bias. Figure 17 The figure shows a comparison between the absorption curve of the NdZnO thin film and the responsivity curve of the detector at different wavelengths. Figure 18 The bar chart shown is a comparison of the ultraviolet / visible light suppression ratio of the detector of this invention and the existing mainstream solar-blind ultraviolet detectors. Figure 19 The diagram shows the working mechanism of the dual built-in electric field of the p-Gr / i-NdZnO / n-Si double heterojunction. Explanation of icon numbers: 1-p-type graphene top electrode layer; 2-intrinsic NdZnO light-absorbing layer; 3-n-type Si substrate. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments: like Figure 1 As shown, the present invention provides an NdZnO-based high suppression ratio self-powered solar-blind ultraviolet photodetector, which is a vertical layered double heterojunction structure, comprising, from top to bottom: p-type graphene top electrode layer 1; Intrinsic NdZnO light-absorbing layer 2; n-type Si substrate 3; The intrinsic NdZnO light-absorbing layer 2 is an amorphous thin film of Zn-doped Nd2O3 with a band gap of 4.43 eV and a light absorption cutoff edge of 280 nm. A first heterojunction is formed between the p-type graphene top electrode layer 1 and the intrinsic NdZnO light-absorbing layer 2, and a second heterojunction is formed between the intrinsic NdZnO light-absorbing layer 2 and the n-type Si substrate 3, forming a p-Gr / i-NdZnO / n-Si dual built-in electric field heterojunction, which is used to realize self-powered solar-blind ultraviolet detection under 0V bias.

[0019] As can be seen from the above description, the present invention has the following beneficial effects: Through the above technical solution, this invention achieves precise bandgap modulation of Nd₂O₃ for the first time, redshifting the absorption cutoff edge from 215nm to 280nm, perfectly matching the solar-blind ultraviolet band. Simultaneously, the p-Gr / i-NdZnO / n-Si double heterojunction structure forms two synergistic built-in electric fields (E1: n-Si→i-NdZnO; E2: i-NdZnO→p-Gr), enabling rapid separation and collection of photogenerated carriers without external bias, effectively solving the problem of excessively high resistivity in Nd₂O₃ and achieving self-powered operation under 0V bias.

[0020] Furthermore, the thickness of the Zn-doped Nd2O3 amorphous thin film ranges from 190 to 200 nm.

[0021] Furthermore, the thickness of the Zn-doped Nd2O3 amorphous thin film is 196 nm.

[0022] As described above, limiting the film thickness within the specified range ensures sufficient absorption efficiency of the light-absorbing layer for solar-blind ultraviolet light, while avoiding excessive thickness that would lead to excessively long carrier transport paths and affect the response speed. 196 nm is the experimentally verified optimal thickness, at which the overall device performance reaches its best.

[0023] Furthermore, the detector exhibits a dark current of 1.44 × 10⁻⁶ under 0V bias and 255nm solar-blind ultraviolet illumination. - ¹¹A, UV / Vis suppression ratio R 255nm / R 532nm ≥7.1×10³.

[0024] As can be seen from the above description, the performance parameters demonstrate the outstanding progress of this invention. Ultra-low dark current (1.44 × 10⁻⁶) - ¹¹A) indicates extremely low background noise. The ultra-high UV / visible light suppression ratio (7.1×10³) shows that the device has extremely high selectivity for solar-blind ultraviolet light and strong resistance to natural light interference, which is far superior to existing rare earth oxide-based solar-blind detectors.

[0025] Furthermore, a Ti / Au composite electrode is disposed on the surface of the p-type graphene top electrode layer, and an In electrode is disposed on the back side of the n-type Si substrate.

[0026] As described above, in the Ti / Au composite electrode, the Ti layer acts as an adhesion layer to enhance the bonding force with graphene, while the Au layer acts as a conductive layer to ensure good electrical signal output; the In electrode forms a good ohmic contact with n-Si, together achieving stable output of electrical signals.

[0027] like Figure 2 As shown, this invention also provides a method for fabricating an NdZnO-based high-suppression-ratio self-powered solar-blind ultraviolet photodetector, comprising the following steps: Step 1: Clean the n-type Si substrate; Step 2: Using room temperature magnetron co-sputtering, with Nd2O3 ceramic target and Zn metal target as sputtering sources, an amorphous thin film of Zn-doped Nd2O3 is deposited on the cleaned n-type Si substrate to obtain the i-NdZnO / n-Si structure. Step 3: Transfer graphene onto the surface of the Zn-doped Nd2O3 amorphous thin film to obtain a p-Gr / i-NdZnO / n-Si double heterojunction structure; Step 4: Prepare a top electrode on the surface of the p-type graphene top electrode layer and prepare a bottom electrode on the back side of the n-type Si substrate to obtain the detector.

[0028] As can be seen from the above description, the present invention has the following beneficial effects: This preparation method employs room temperature magnetron co-sputtering and graphene wet transfer processes. The entire preparation process is completed at room temperature, eliminating the need for complex high-temperature equipment. The process parameters are controllable and have good repeatability, making it suitable for large-scale industrial production.

[0029] Furthermore, the process parameters for magnetron co-sputtering described in step 2 are as follows: The sputtering atmosphere was a room temperature oxygen-free doping environment. The Nd2O3 target power was 80W, the Zn target power was 60W, and the sputtering time was 20min, resulting in a Zn-doped Nd2O3 amorphous thin film with a band gap of 4.43eV and an absorption cutoff edge of 280nm.

[0030] As described above, by optimizing the sputtering parameters, especially by precisely controlling the ratio of Zn target power to Nd2O3 target power, the Zn doping concentration can be precisely controlled, thereby precisely adjusting the Nd2O3 bandgap from 5.75eV to 4.43eV, and achieving an ideal solar blind band of 280nm absorption cutoff edge.

[0031] Furthermore, the graphene transfer described in step 3 specifically involves: The PMMA / Gr / Cu composite film was immersed in an etching solution to remove the Cu substrate. After cleaning, it was transferred to the surface of the Zn-doped Nd2O3 amorphous thin film. Then, the PMMA was removed to obtain a p-Gr / i-NdZnO / n-Si double heterojunction structure.

[0032] As described above, the PMMA-assisted wet transfer technique can produce complete and clean graphene films, ensuring the formation of a high-quality heterojunction interface between graphene and NdZnO films, which is beneficial for the stable formation of the built-in electric field.

[0033] Furthermore, the corrosive solution is an ammonium persulfate solution with a concentration of 0.1 mol / L and a corrosion time of 12 h.

[0034] As described above, ammonium persulfate etching solution can gently and uniformly remove Cu substrate, avoiding damage to graphene film and ensuring the structural integrity and electrical properties of graphene after transfer.

[0035] Furthermore, the top electrode in step 4 is a Ti / Au composite electrode, prepared by vacuum thermal evaporation, wherein the Ti layer thickness is 50 nm and the Au layer thickness is 200 nm; the bottom electrode is an In electrode, prepared by welding.

[0036] As described above, the vacuum thermal evaporation method can obtain dense and uniform metal electrodes. The Ti layer (50nm) serves as an adhesion layer to enhance the bonding force with graphene, and the Au layer (200nm) serves as a conductive layer to ensure low-resistance contact. The In electrode is welded to the back of the n-Si to form a good ohmic contact.

[0037] The following are several preferred embodiments or application embodiments to help those skilled in the art better understand the technical content of the present invention and the technical contributions made by the present invention compared with the prior art: Example 1: See Figures 1 to 19 As shown, the present invention provides an NdZnO-based high suppression ratio self-powered solar-blind ultraviolet photodetector, which is a vertical layered double heterojunction structure, comprising, from top to bottom: p-type graphene top electrode layer 1; Intrinsic NdZnO light-absorbing layer 2; n-type Si substrate 3; The intrinsic NdZnO light-absorbing layer 2 is an amorphous thin film of Zn-doped Nd2O3 with a band gap of 4.43 eV and a light absorption cutoff edge of 280 nm; the thickness of the Zn-doped Nd2O3 amorphous thin film is 196 nm.

[0038] A first heterojunction is formed between the p-type graphene top electrode layer 1 and the intrinsic NdZnO light-absorbing layer 2, and a second heterojunction is formed between the intrinsic NdZnO light-absorbing layer 2 and the n-type Si substrate 3, constituting a p-Gr / i-NdZnO / n-Si dual built-in electric field heterojunction for achieving self-powered solar-blind ultraviolet detection under 0V bias. A Ti / Au composite electrode is disposed on the surface of the p-type graphene top electrode layer 1, and an In electrode is disposed on the back side of the n-type Si substrate 3.

[0039] The detector exhibits a dark current of 1.44 × 10⁻⁶ under 0V bias and 255nm solar-blind ultraviolet illumination. - ¹¹A, UV / Vis suppression ratio R 255nm / R 532nm ≥7.1×10³.

[0040] The fabrication method of the aforementioned NdZnO-based high suppression ratio self-powered solar-blind ultraviolet photodetector is as follows: 1. Substrate cleaning Take an n-type Si (100) substrate, sonicate it with acetone for 15 min and anhydrous ethanol for 15 min in sequence, soak it in 5% dilute hydrofluoric acid solution for 30 s to remove the surface oxide layer, rinse it with deionized water 5 times, blow it dry with high-purity nitrogen, and set it aside.

[0041] 2. Preparation of NdZnO thin films A magnetron co-sputtering system was used to deposit an NdZnO thin film on a cleaned n-type Si substrate, employing an Nd₂O₃ ceramic target (99.99% purity) as the Nd source and a Zn metal target (99.99% purity) as the Zn source. The sputtering process parameters were: a cavity back-bottom vacuum level better than 1×10⁻⁶. -4 The sputtering process was conducted using high-purity Ar gas (99.999% purity) at a working pressure of 0.8 Pa, substrate temperature at room temperature, Nd₂O₃ target sputtering power of 80 W, Zn target sputtering power of 60 W, and sputtering time of 20 min to obtain an amorphous Zn-doped Nd₂O₃ thin film. Measurements showed that the film thickness was approximately 196 nm, the band gap was 4.43 eV, and the light absorption cutoff edge was 280 nm.

[0042] 3. Graphene transfer A PMMA / Gr / Cu composite film (PMMA being polymethyl methacrylate and Gr being graphene) was immersed in 0.1 mol / L ammonium persulfate etching solution and etched at room temperature for 12 hours to completely remove the Cu substrate. The etched PMMA / Gr film was repeatedly washed with deionized water, transferred to the surface of an NdZnO film, and allowed to air dry. Then, it was washed sequentially with acetone, anhydrous ethanol, and deionized water to remove PMMA, yielding a p-Gr / i-NdZnO / n-Si double heterojunction structure.

[0043] 4. Electrode preparation A Ti / Au composite electrode was deposited on the surface of p-type graphene using a vacuum thermal evaporation method, with a 50 nm thick Ti layer serving as an adhesion layer and a 200 nm thick Au layer serving as a conductive layer. An In electrode was then welded to the back side of an n-type Si substrate to complete the fabrication of the entire NdZnO-based solar-blind ultraviolet photodetector.

[0044] Example 2: Detector Performance Testing The photoelectric performance of the NdZnO-based solar-blind ultraviolet photodetector prepared in Example 1 was tested under the following conditions: room temperature, 0V bias voltage, and 255nm solar-blind ultraviolet light as incident light. The specific test results are as follows: Dark current: The dark current at 0V bias is 1.44 × 10⁻⁶. - ¹¹A, with ultra-low background noise (see appendix) Figure 9 ); Self-powered characteristic: An open-circuit voltage is generated under 255nm illumination, and this voltage increases from 0.1V to 0.14V with increasing optical power density, achieving self-powered operation (see appendix). Figure 10 ); Response performance: At an optical power density of 10.4 μW / cm², the responsivity reaches 4.34 mA / W, and the detectivity is 6.07 × 10¹¹ Jones (see appendix). Figure 12 ); Response speed: At an optical power density of 125.4 μW / cm², the rise time is 140 ms and the decay time is 89 ms. Furthermore, the response time remains stable between 70-165 ms under different optical power densities, demonstrating fast and stable response capabilities (see appendix). Figure 14 and Figure 15 ); Spectral selectivity: It shows a significant response only to solar-blind ultraviolet light in the 200-280 nm range, and almost no response to visible light (532 nm). The ultraviolet / visible light suppression ratio reaches 7.1 × 10³, exhibiting extremely strong anti-interference ability (see appendix). Figure 16 , Figure 17 as well as Figure 18 ).

[0045] Example 3: Working Mechanism of Dual Built-in Electric Fields See appendix Figure 19 The p-Gr / i-NdZnO / n-Si double heterojunction structure of this invention forms two synergistic built-in electric fields in the dark state: the first built-in electric field E1 points from the n-type Si substrate to the intrinsic NdZnO light-absorbing layer, and the second built-in electric field E2 points from the intrinsic NdZnO light-absorbing layer to the p-type graphene top electrode layer. When irradiated with 255nm solar-blind ultraviolet light, the intrinsic NdZnO light-absorbing layer absorbs photons, generating electron-hole pairs. Under the synergistic effect of the two built-in electric fields, photogenerated electrons drift towards the n-type Si substrate, and photogenerated holes drift towards the p-type graphene top electrode layer, thereby achieving efficient separation and collection of photogenerated carriers. The entire process requires no external bias voltage, achieving self-powered operation.

[0046] Example 4: Verification of the beneficial effects of the preparation method The preparation method described in Example 1 was used, and the entire preparation process was completed at room temperature, without the need for high-temperature annealing or complex high-vacuum equipment. The magnetron co-sputtering process parameters (80W Nd₂O₃ target, 60W Zn target) allowed for precise control of the Zn doping concentration, ensuring accurate bandgap tuning to 4.43 eV. The wet graphene transfer process is mature and can achieve large-area, high-quality graphene film transfer. The vacuum thermal evaporation process for the Ti / Au electrode and the welding process for the In electrode are both mature industrial technologies. The entire preparation method is simple, reproducible, and low-cost, making it suitable for large-scale industrial production.

[0047] Example 5: The difference between this embodiment and Embodiment 1 is that the thickness of the Zn-doped Nd₂O₃ amorphous thin film is 190 nm. All other parts are the same and will not be described again here.

[0048] Example 6: The difference between this embodiment and Embodiment 1 is that the thickness of the Zn-doped Nd₂O₃ amorphous thin film is 200 nm. All other parts are the same and will not be described again here.

[0049] In summary, the NdZnO-based high suppression ratio self-powered solar-blind ultraviolet photodetector and its fabrication method provided by this invention have the advantages of novel material system, innovative device structure, excellent comprehensive performance, and simple fabrication process. It can be widely used in solar-blind ultraviolet detection scenarios such as ultraviolet communication, fire monitoring, high voltage corona detection, and biochemical detection. It is especially suitable for miniaturized and portable photodetector systems with high power consumption and integration requirements, and has broad industrial application prospects.

[0050] The present invention has been described with reference to the foregoing embodiments and accompanying drawings; however, the foregoing embodiments are merely examples for implementing the present invention. It must be noted that the disclosed embodiments do not limit the scope of the present invention. Conversely, modifications and equivalents included within the spirit and scope of the claims are all included within the scope of the present invention.

Claims

1. A self-powered solar-blind ultraviolet photodetector with high suppression ratio based on NdZnO, characterized in that, It is a vertically layered double heterojunction structure, consisting of the following from top to bottom: p-type graphene top electrode layer; Intrinsic NdZnO light-absorbing layer; n-type Si substrate; The intrinsic NdZnO light-absorbing layer is an amorphous thin film of Zn-doped Nd2O3 with a band gap of 4.43 eV and a light absorption cutoff edge of 280 nm. A first heterojunction is formed between the p-type graphene top electrode layer and the intrinsic NdZnO light-absorbing layer, and a second heterojunction is formed between the intrinsic NdZnO light-absorbing layer and the n-type Si substrate, forming a p-Gr / i-NdZnO / n-Si dual built-in electric field heterojunction, which is used to realize self-powered solar-blind ultraviolet detection under 0V bias.

2. The NdZnO-based high suppression ratio self-powered solar-blind ultraviolet photodetector according to claim 1, characterized in that, The thickness of the Zn-doped Nd2O3 amorphous thin film ranges from 190 to 200 nm.

3. The NdZnO-based high suppression ratio self-powered solar-blind ultraviolet photodetector according to claim 2, characterized in that, The thickness of the Zn-doped Nd₂O₃ amorphous thin film is 196 nm.

4. The NdZnO-based high suppression ratio self-powered solar-blind ultraviolet photodetector according to claim 1, characterized in that, The detector exhibits a dark current of 1.44 × 10⁻⁶ under 0V bias and 255nm solar-blind ultraviolet illumination. - ¹¹A, UV / Vis suppression ratio R 255nm / R 532nm ≥7.1×10³.

5. The NdZnO-based high suppression ratio self-powered solar-blind ultraviolet photodetector according to claim 1, characterized in that, A Ti / Au composite electrode is disposed on the surface of the p-type graphene top electrode layer, and an In electrode is disposed on the back side of the n-type Si substrate.

6. A method for fabricating a self-powered solar-blind ultraviolet photodetector with high suppression ratio based on NdZnO as described in any one of claims 1-5, characterized in that, Includes the following steps: Step 1: Clean the n-type Si substrate; Step 2: Using room temperature magnetron co-sputtering, with Nd2O3 ceramic target and Zn metal target as sputtering sources, an amorphous thin film of Zn-doped Nd2O3 is deposited on the cleaned n-type Si substrate to obtain the i-NdZnO / n-Si structure. Step 3: Transfer graphene onto the surface of the Zn-doped Nd2O3 amorphous thin film to obtain a p-Gr / i-NdZnO / n-Si double heterojunction structure; Step 4: Prepare a top electrode on the surface of the p-type graphene top electrode layer and prepare a bottom electrode on the back side of the n-type Si substrate to obtain the detector.

7. The method for fabricating an NdZnO-based high-suppression-ratio self-powered solar-blind ultraviolet photodetector according to claim 6, characterized in that, The process parameters for magnetron co-sputtering in step 2 are as follows: The sputtering atmosphere was a room temperature oxygen-free doping environment. The Nd2O3 target power was 80W, the Zn target power was 60W, and the sputtering time was 20min, resulting in a Zn-doped Nd2O3 amorphous thin film with a band gap of 4.43eV and an absorption cutoff edge of 280nm.

8. The method for fabricating a self-powered solar-blind ultraviolet photodetector with high suppression ratio based on NdZnO according to claim 6, characterized in that, The graphene transfer described in step 3 specifically involves: The PMMA / Gr / Cu composite film was immersed in an etching solution to remove the Cu substrate. After cleaning, it was transferred to the surface of the Zn-doped Nd2O3 amorphous thin film. Then, the PMMA was removed to obtain a p-Gr / i-NdZnO / n-Si double heterojunction structure.

9. The method for fabricating a self-powered solar-blind ultraviolet photodetector with high suppression ratio based on NdZnO according to claim 8, characterized in that, The corrosive solution is an ammonium persulfate solution with a concentration of 0.1 mol / L and a corrosion time of 12 h.

10. The method for fabricating an NdZnO-based high-suppression-ratio self-powered solar-blind ultraviolet photodetector according to claim 6, characterized in that, The top electrode in step 4 is a Ti / Au composite electrode, which is prepared by vacuum thermal evaporation, wherein the Ti layer has a thickness of 50 nm and the Au layer has a thickness of 200 nm; the bottom electrode is an In electrode, which is prepared by welding.

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