Beta-ga2o3 / yb2o3 heterojunction self-driven detector for solar blind ultraviolet light communication

Abstract

The application discloses a beta-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar blind ultraviolet light communication and relates to the technical field of photoelectric detectors. From bottom to top, the beta-Ga2O3 / Yb2O3 heterojunction self-driven detector comprises a sapphire substrate, a beta-Ga2O3 film layer, a Yb2O3 film layer and an Ag electrode in sequence; the beta-Ga2O3 film layer and the Yb2O3 film layer form a beta-Ga2O3 / Yb2O3 heterojunction structure. The band gaps of beta-Ga2O3 and Yb2O3 are 4.9 eV and 5.4 eV, and the corresponding light absorption cutoff wavelengths are 254 nm and 229 nm, respectively, which are located in the solar blind ultraviolet band. The beta-Ga2O3 / Yb2O3 heterojunction has a type-II band arrangement structure, which is beneficial to the separation of photo-generated carriers, the improvement of the light response of the device and the self-driven detection of solar blind ultraviolet light. The self-driven solar blind ultraviolet light communication system constructed based on the beta-Ga2O3 / Yb2O3 heterojunction has a high signal-to-noise ratio and high anti-interference capability and only responds to solar blind light. The heterojunction film constructed by the application is prepared by using the plasma enhanced chemical vapor deposition technology and the sol-gel method, has good process controllability and repeatability, is low in cost and can be prepared in large quantities.

Description

Technical Field

[0001] This invention relates to the field of photodetector technology, specifically to a β-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar-blind ultraviolet communication. Background Technology

[0002] Solar-blind ultraviolet light with wavelengths of 200-280nm is absorbed by the atmosphere and ozone, resulting in extremely low intensity reaching the ground. This gives detection technologies based on this band core advantages such as low background noise, strong anti-interference capabilities, and high detection accuracy, making them indispensable core technologies in many key fields. With the iterative upgrades of semiconductor technology, the application scenarios of solar-blind ultraviolet detection have expanded from traditional fire early warning, environmental monitoring, biosensing, and national defense and security to high-end scenarios such as solar-blind ultraviolet communication, power safety monitoring (high-voltage arc discharge detection), deep space exploration, solar-blind imaging and light trajectory tracking, portable detection equipment, and industrial process control. It plays an irreplaceable role in high-end manufacturing, national defense technology, and public safety, with particularly urgent demand in detection under extreme environments (high temperature, high pressure, high radiation).

[0003] β-Ga₂O₃ has a bandgap of approximately 4.9 eV, which highly matches the photon energy of solar-blind ultraviolet light (4.43-6.20 eV). It also possesses excellent thermal and chemical stability and a high critical breakdown field strength, enabling high wavelength selectivity without expensive filters, making it an ideal material for fabricating high-performance solar-blind ultraviolet photodetectors. However, pure β-Ga₂O₃ has inherent defects: low carrier mobility, rapid photogenerated carrier recombination rate, and high dark current. This leads to common problems in pure β-Ga₂O₃-based photodetectors, such as low responsivity, slow response speed, poor stability, and high dark current, making it difficult to meet the stringent requirements of the latest applications. Constructing heterojunctions is a core and effective means to improve the performance of β-Ga₂O₃-based detectors. By matching the bandgap of the two semiconductor materials, efficient separation of photogenerated carriers can be achieved, carrier recombination can be suppressed, and dark current can be reduced, thereby improving the photoelectric performance and stability of the detector and adapting it to the application requirements of extreme environments and high-end scenarios. Ytterbium oxide (Yb2O3), as a wide bandgap semiconductor oxide, has a bandgap of approximately 5.42 eV, which is highly matched with the bandgap of β-Ga2O3. It also possesses good thermal stability, optical properties, and radiation resistance, making it suitable for extreme application environments such as high pressure and deep space. Constructing a heterojunction with β-Ga2O3 can fully leverage the synergistic effect of the two materials to build a novel high-performance self-driven solar-blind ultraviolet photodetector.

[0004] Current detectors cannot meet the diverse and high-end demands of various fields for high-performance, high-stability, self-driven solar-blind ultraviolet detectors. Therefore, this invention develops a β-Ga2O3 / Yb2O3 heterojunction self-driven photodetector for solar-blind ultraviolet optical communication, improving detection performance to adapt to the latest application scenarios. It also improves the gallium oxide-based solar-blind ultraviolet detection technology system, helping my country achieve full-chain technological self-sufficiency and control in this field, and has significant research significance and industrialization value. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a β-Ga2O3 / Yb2O3 heterojunction self-driven photodetector for solar-blind ultraviolet communication and its fabrication method. This invention achieves high sensitivity, fast response characteristics, low dark current, and stable self-driving performance in a solar-blind ultraviolet photodetector, while simplifying the fabrication process, reducing costs, and facilitating large-scale production.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a β-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar-blind ultraviolet communication, comprising, from bottom to top: a sapphire substrate, a β-Ga2O3 thin film layer, a Yb2O3 thin film layer, and an Ag electrode; the β-Ga2O3 thin film layer and the Yb2O3 thin film layer constitute a β-Ga2O3 / Yb2O3 heterojunction bilayer film structure.

[0007] Specifically, the sapphire substrate is a c-plane sapphire substrate with a thickness of 300-500 μm and a polished surface with a surface roughness Ra ≤ 0.5 nm. The sapphire substrate and the β-Ga₂O₃ thin film layer have the same length × width, both being 1.0 cm × 1.0 cm to 2.0 cm × 2.0 cm, and the β-Ga₂O₃ thin film layer has a thickness of 0.1-2 μm. The Yb₂O₃ thin film layer has a length × width of 0.5 cm × 1.0 cm to 1.0 cm × 2.0 cm and a thickness of 0.1-1.0 μm. Ag electrodes are disposed on both the β-Ga₂O₃ thin film layer and the Yb₂O₃ thin film layer, and the Ag electrodes have a thickness of 50-100 nm.

[0008] Preferably, the β-Ga2O3 thin film layer is deposited on a sapphire substrate using plasma-enhanced chemical vapor deposition (PECVD) technology, and a Yb2O3 thin film layer is prepared in a selected area above the β-Ga2O3 thin film layer using a sol-gel method with a mask. The two form a type II heterojunction structure, and Ag electrodes are deposited on the β-Ga2O3 thin film layer and the Yb2O3 thin film layer respectively using a thermal evaporation process.

[0009] Furthermore, the strong built-in electric field formed near the heterojunction interface by the β-Ga2O3 / Yb2O3 heterojunction structure can effectively block the diffusion of majority carriers under no-light conditions, thereby suppressing the dark current to an extremely low level; and can promote the effective separation and transport of photogenerated carriers, thereby enabling the device to have self-driving characteristics, while improving the device's response speed and sensitivity.

[0010] Preferably, the method for fabricating a high-performance self-driven solar-blind ultraviolet photodetector based on a β-Ga2O3 / Yb2O3 heterojunction includes the following steps:

[0011] Step 1: Sapphire substrate pretreatment: The sapphire substrate is ultrasonically cleaned with acetone, anhydrous ethanol and deionized water for 10-20 minutes in sequence. After cleaning, most of the moisture is dried with high-purity nitrogen (purity ≥99.99%) and placed in an oven at 100-150℃ to dry the remaining moisture.

[0012] Step 2: Deposit β-Ga2O3 thin film using PECVD: Place a liquid gallium source (purity ≥99.99%) in a quartz boat, and invert the cleaned and dried sapphire substrate inside the quartz boat. Then, place the quartz boat in the center of the quartz tube of the PECVD equipment. Seal the quartz tube opening and turn on the vacuum pump to evacuate the quartz tube. After the vacuum degree of the quartz tube reaches below 1~3 Pa, open the argon cylinder valve and introduce high-purity argon gas (purity ≥99.99%) at a flow rate of 80~100 sccm into the quartz tube. After the temperature inside the quartz tube rises to 750~1000℃ at a rate of 10℃ / min, introduce high-purity oxygen gas (purity ≥99.99%) at a flow rate of 5~8 sccm as the reaction gas. During the reaction, set the RF power to 130~200W. After reacting for 35~60min, close the RF and oxygen cylinder valves. After the temperature inside the tube dropped to room temperature, the valve of the argon cylinder was closed, and the quartz boat was removed from the quartz tube opening, thus completing the preparation of the β-Ga2O3 thin film layer with sapphire as the substrate;

[0013] Step 3: Prepare Yb2O3 thin film using sol-gel method: Use a mask to cover a selected area of ​​the β-Ga2O3 thin film layer, and use a pipette to spin-coat a certain amount of Yb2O3 precursor sol onto the unmasked area of ​​the β-Ga2O3 thin film layer. After drying at 100~150℃ for 10~20min, transfer the sample to a muffle furnace for high-temperature annealing in air atmosphere to form a smooth and dense Yb2O3 thin film layer. This completes the preparation of the Yb2O3 thin film layer and constructs a β-Ga2O3 / Yb2O3 heterojunction bilayer film with sapphire as the substrate.

[0014] Step 4: Prepare Ag electrodes using thermal evaporation: Ag electrodes are deposited on the β-Ga2O3 thin film layer and Yb2O3 thin film layer respectively using a mask and thermal evaporation process, thus completing the preparation of the device electrodes.

[0015] Preferably, in step three, the process parameters for preparing Yb2O3 thin films using the sol-gel method are as follows: using ytterbium nitrate hydrate Yb(NO3)3·5H2O with a purity ≥99.99% as a precursor, 2-methoxyethanol as a solvent, citric acid as a chelating agent, and holding in a water bath at 60~80℃ for 2~4h; the spin-coating parameters are: spin-coating speed of 3000~6000r / min, spin-coating time of 30~60s, and the annealing temperature of the high-temperature annealing treatment is 500~750℃, the heating rate is 10℃ / min, and the annealing time is 1~4h.

[0016] Preferably, in step four, the process parameters for preparing the Ag electrode by thermal evaporation are as follows: using Ag particles with a purity of ≥99.99% as the evaporation source, the evaporation current is 80~120A, and the evaporation time is 3~5min.

[0017] This invention provides a β-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar-blind ultraviolet communication. It possesses the following advantages:

[0018] 1. The strong built-in electric field formed near the bilayer membrane interface of the β-Ga2O3 / Yb2O3 heterojunction bilayer film structure constructed in this invention can effectively block the diffusion of majority carriers under no-light conditions, thereby suppressing the dark current to an extremely low level; and can promote the effective separation and transport of photogenerated carriers, thereby enabling the device to have self-driving characteristics, while improving the device's photo-dark current ratio, response speed, sensitivity, etc.

[0019] 2. This invention uses the sol-gel method to prepare Yb2O3 thin films on β-Ga2O3 thin films. This method has the advantages of low cost, simple process, uniform coating, and strong adhesion to the substrate. It can reduce the defect state density at the heterojunction interface and further optimize the carrier transport efficiency. At the same time, the sol-gel method does not require complex vacuum equipment, which reduces the preparation cost.

[0020] 3. The overall preparation process of this invention is simple, low-cost, highly controllable, and highly repeatable. It does not require complex equipment or harsh preparation conditions. The PECVD method, sol-gel method, and thermal evaporation method involved in the device preparation process are mature and easy to achieve large-scale production, thus having significant industrial application value. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of a β-Ga2O3 / Yb2O3 heterojunction self-driven photodetector for solar-blind ultraviolet communication prepared by the method of this invention.

[0022] Figure 2 This is a cross-sectional SEM image of the β-Ga2O3 / Yb2O3 heterojunction prepared using the method of this invention;

[0023] Figure 3 The images show the XRD patterns of β-Ga2O3 thin films, Yb2O3 thin films, and β-Ga2O3 / Yb2O3 heterojunction bilayer thin films prepared by the method of this invention.

[0024] Figure 4 The light absorption spectra and Tauc diagrams of β-Ga2O3 thin films and Yb2O3 thin films prepared by the method of this invention are shown.

[0025] Figure 5 This is a stability test of the solar-blind ultraviolet photodetector prepared by the method of this invention when it is working in self-driven mode.

[0026] Figure 6 The photodetector prepared using the method of this invention is used for testing solar-blind ultraviolet communication. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1:

[0029] The c-plane sapphire substrate was cut into multiple 1.0cm × 1.0cm pieces using a UV dicing machine. The sapphire substrate was then ultrasonically cleaned sequentially with acetone, anhydrous ethanol, and deionized water for 15 minutes each. After cleaning, it was dried with high-purity nitrogen and then thoroughly dried in a 120°C oven. The clean, dry sapphire substrate was inverted and placed on a quartz boat. 40 μL of liquid gallium metal with a purity ≥99.99% was pipetted and placed approximately 4 cm from one side of the substrate. The quartz boat was then transferred into the quartz reaction tube of the PECVD equipment and placed in the central heating zone. After sealing the quartz reaction tube, the vacuum pump was turned on to create a vacuum. Once the vacuum level inside the tube dropped below 1 Pa, the argon cylinder valve was opened, and argon gas at a flow rate of 80 sccm was introduced as a protective gas. The temperature inside the tubular furnace was increased to 850°C at a rate of 10°C / min. Then, the oxygen cylinder valve was opened, and oxygen at a flow rate of 5 sccm was introduced to participate in the reaction. Turn on the RF power supply, set the RF power to 150W and the growth time to 35min, and deposit a β-Ga2O3 thin film on the sapphire substrate. After 35min, stop the oxygen supply and turn off the RF power supply. When the tube furnace temperature naturally drops to near room temperature, stop the argon gas supply and remove the β-Ga2O3 thin film sample.

[0030] A mask was used to shield one half of the β-Ga₂O₃ film. 30 μL of a prepared Yb₂O₃ precursor solution was transferred using a pipette and spin-coated onto the unshielded β-Ga₂O₃ film surface at a spin-coating speed of 6000 r / min and a spin-coating time of 30 s. After drying on a 100℃ drying stage for 15 min, the sample was transferred to a muffle furnace and annealed at 600℃ for 4 h in air to form a smooth and dense Yb₂O₃ film layer. Using a mask combined with thermal evaporation, Ag particles with a purity ≥99.99% were used as the evaporation source. The evaporation current was 80 A, and the evaporation time was 3 min. Ag electrodes were deposited above both the β-Ga₂O₃ and Yb₂O₃ film areas to serve as electrodes for testing the electrical performance of the device.

[0031] Following the experimental methods and procedures described above, a β-Ga₂O₃ / Yb₂O₃ heterojunction self-driven photodetector for solar-blind ultraviolet communication can be prepared. A schematic diagram of the device structure is shown below. Figure 1 As shown. Figure 2 The image shows a cross-sectional SEM image of the β-Ga2O3 / Yb2O3 heterojunction bilayer film prepared by the method of this invention. A clear heterojunction interface can be observed. The thickness of the Yb2O3 film layer is measured to be 128.4 nm, and the thickness of the β-Ga2O3 film layer is 385.2 nm.

[0032] Figure 3The XRD patterns of the β-Ga2O3 film, Yb2O3 film, and β-Ga2O3 / Yb2O3 heterojunction bilayer film prepared by the method of the present invention are shown. The diffraction peak at 41.65° corresponds to the c-plane of sapphire. The diffraction peaks of the β-Ga2O3 film are located at 19.12°, 38.59°, and 59.29°, which correspond to the (-201), (-402), and (-603) crystal planes of β-Ga2O3, respectively, indicating that the β-Ga2O3 film deposited on the sapphire substrate by PECVD grows along the [-201] crystal direction. The diffraction peak of the Yb2O3 film is located at 29.63°, which corresponds to the (222) crystal plane of Yb2O3, indicating that the Yb2O3 film prepared on the sapphire substrate by spin coating grows along the

[111] crystal direction. The diffraction peaks of the β-Ga2O3 / Yb2O3 heterojunction bilayer film include all the diffraction peaks of both the β-Ga2O3 and Yb2O3 films, confirming the successful construction of the β-Ga2O3 / Yb2O3 heterojunction bilayer film. Figure 4 The light absorption spectra and Tauc diagrams of the β-Ga₂O₃ and Yb₂O₃ thin films prepared by the method of this invention are shown. The linear regions in the Tauc diagrams are linearly extended to intersect the baseline. The intersection points are used to estimate the band gaps of the prepared β-Ga₂O₃ and Yb₂O₃ thin films to be 4.88 eV and 5.42 eV, respectively, corresponding to light absorption cutoff wavelengths of 254 nm and 229 nm, respectively, which can completely shield stray light interference other than solar-blind ultraviolet light. The stability of the detector during long-term operation in self-driven mode was tested, such as... Figure 5 As shown, the device maintained almost unchanged photocurrent response even after continuous exposure for up to 3 hours, demonstrating excellent stability. Figure 6 As shown, if the solar-blind ultraviolet light signal sequence representing G, a, Y, and b is sent using ASCII encoding, and a β-Ga2O3 / Yb2O3 heterojunction self-driven photodetector is used as the receiving end, then according to the decoding rule that photocurrent represents "1", dark current represents "0", and the single cycle of character recognition is defined as 5 s, the sent letters G, a, Y, and b can be accurately decoded.

[0033] Example 2

[0034] The c-plane sapphire substrate was cut into multiple 1.0cm × 1.0cm pieces using a UV dicing machine. The sapphire substrate was then ultrasonically cleaned sequentially with acetone, anhydrous ethanol, and deionized water for 15 minutes each. After cleaning, it was dried with high-purity nitrogen and then thoroughly dried in a 120°C oven. The clean, dry sapphire substrate was inverted and placed on a quartz boat. 30 μL of 99.99% pure liquid gallium was pipetted and placed approximately 4 cm from one side of the substrate. The quartz boat was then transferred into the quartz reaction tube of the PECVD equipment and placed in the central heating zone. After sealing the quartz reaction tube, a vacuum pump was turned on to create a vacuum. Once the vacuum level inside the tube dropped below 2 Pa, the argon cylinder valve was opened, and argon gas at a flow rate of 90 sccm was introduced as a protective gas. The temperature inside the tubular furnace was increased to 800°C at a rate of 10°C / min. Then, the oxygen cylinder valve was opened, and oxygen at a flow rate of 5 sccm was introduced to participate in the reaction. Turn on the RF power supply, set the RF power to 130W and the growth time to 50min, and deposit a β-Ga2O3 thin film on the sapphire substrate. After 50min, stop the oxygen supply and turn off the RF power supply. When the tube furnace temperature naturally drops to near room temperature, stop the argon supply and remove the β-Ga2O3 thin film sample.

[0035] A mask was used to shield one half of the β-Ga₂O₃ thin film. 30 μL of a prepared Yb₂O₃ precursor solution was transferred using a pipette and spin-coated onto the unshielded β-Ga₂O₃ film surface at a spin speed of 3000 r / min and a spin time of 30 s. After drying on a 100℃ drying table for 20 min, the sample was transferred to a muffle furnace and annealed at 700℃ for 1 h in air to form a smooth and dense Yb₂O₃ thin film layer. Using a mask combined with thermal evaporation, Ag particles with a purity ≥99.99% were used as the evaporation source. The evaporation current was 80 A, and the evaporation time was 3 min. Ag electrodes were deposited above both the β-Ga₂O₃ and Yb₂O₃ film regions to serve as electrodes for testing the electrical performance of the device.

[0036] The composition, structure, and performance of the β-Ga2O3 / Yb2O3 heterojunction self-driven photodetector used for solar-blind ultraviolet communication are similar to those in Example 1.

[0037] Example 3

[0038] The c-plane sapphire substrate was cut into multiple 1.0cm × 1.0cm pieces using a UV dicing machine. The sapphire substrate was then ultrasonically cleaned sequentially with acetone, anhydrous ethanol, and deionized water for 10 minutes each. After cleaning, it was dried with high-purity nitrogen and then thoroughly dried in a 120°C oven. The clean, dry sapphire substrate was inverted and placed on a quartz boat. 40 μL of 99.99% pure liquid gallium was pipetted and placed approximately 5 cm from one side of the substrate. The quartz boat was then transferred into the quartz reaction tube of the PECVD equipment and placed in the central heating zone. After sealing the quartz reaction tube, the vacuum pump was turned on to create a vacuum. Once the vacuum level inside the tube dropped below 1 Pa, the argon cylinder valve was opened, and argon gas at a flow rate of 100 sccm was introduced as a protective gas. The temperature inside the tubular furnace was increased to 900°C at a rate of 10°C / min. Then, the oxygen cylinder valve was opened, and oxygen at a flow rate of 6 sccm was introduced to participate in the reaction. Turn on the RF power supply, set the RF power to 200W and the growth time to 40min, and deposit a β-Ga2O3 thin film on the sapphire substrate. After 40min, stop the oxygen supply and turn off the RF power supply. When the tube furnace temperature naturally drops to near room temperature, stop the argon gas supply and remove the β-Ga2O3 thin film sample.

[0039] A mask was used to shield one half of the β-Ga₂O₃ film. 50 μL of a prepared Yb₂O₃ precursor solution was transferred using a pipette and spin-coated onto the unshielded β-Ga₂O₃ film surface at a spin speed of 5000 r / min and a spin time of 30 s. After drying on a 120℃ drying stage for 15 min, the sample was transferred to a muffle furnace and annealed at 650℃ for 2 h in air to form a smooth and dense Yb₂O₃ film layer. Using a mask combined with thermal evaporation, Ag particles with a purity ≥99.99% were used as the evaporation source. The evaporation current was 80 A, and the evaporation time was 4 min. Ag electrodes were deposited above both the β-Ga₂O₃ and Yb₂O₃ film areas to serve as electrodes for testing the electrical performance of the device.

[0040] The composition, structure, and performance of the β-Ga2O3 / Yb2O3 heterojunction self-driven photodetector used for solar-blind ultraviolet communication are similar to those in Example 1.

[0041] Example 4

[0042] The c-plane sapphire substrate was cut into multiple 1.0cm × 1.0cm pieces using a UV dicing machine. The sapphire substrate was then ultrasonically cleaned sequentially with acetone, anhydrous ethanol, and deionized water for 15 minutes each. After cleaning, it was dried with high-purity nitrogen and then thoroughly dried in a 120°C oven. The clean, dry sapphire substrate was placed upside down on a quartz boat. 25 μL of 99.99% pure liquid gallium was pipetted and placed approximately 3 cm from one side of the substrate. The quartz boat was then transferred into the quartz reaction tube of the PECVD equipment and placed in the central heating zone. After sealing the quartz reaction tube, the vacuum pump was turned on to create a vacuum. Once the vacuum level inside the tube dropped below 1.5 Pa, the argon cylinder valve was opened, and argon gas at a flow rate of 80 sccm was introduced as a protective gas. The temperature inside the tubular furnace was increased to 780°C at a rate of 10°C / min. Then, the oxygen cylinder valve was opened, and oxygen at a flow rate of 7 sccm was introduced to participate in the reaction. Turn on the RF power supply, set the RF power to 170W and the growth time to 50min, and deposit a β-Ga2O3 thin film on the sapphire substrate. After 50min, stop the oxygen supply and turn off the RF power supply. When the tube furnace temperature naturally drops to near room temperature, stop the argon supply and remove the β-Ga2O3 thin film sample.

[0043] A mask was used to shield one half of the β-Ga₂O₃ film. 40 μL of a prepared Yb₂O₃ precursor solution was transferred using a pipette and spin-coated onto the unshielded β-Ga₂O₃ film surface at a spin speed of 4000 r / min and a spin time of 30 s. After drying on a 120℃ drying stage for 20 min, the sample was transferred to a muffle furnace and annealed at 500℃ for 4 h in air to form a smooth and dense Yb₂O₃ film layer. Using a mask combined with thermal evaporation, Ag particles with a purity ≥99.99% were used as the evaporation source. The evaporation current was 80 A, and the evaporation time was 3 min. Ag electrodes were deposited above both the β-Ga₂O₃ and Yb₂O₃ film areas to serve as electrodes for testing the electrical performance of the device.

[0044] The composition, structure, and performance of the β-Ga2O3 / Yb2O3 heterojunction self-driven photodetector used for solar-blind ultraviolet communication are similar to those in Example 1.

[0045] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A β-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar-blind ultraviolet communication, characterized in that, From bottom to top, it includes: a sapphire substrate, a β-Ga2O3 thin film layer, a Yb2O3 thin film layer, and an Ag electrode; the β-Ga2O3 thin film layer and the Yb2O3 thin film layer form a β-Ga2O3 / Yb2O3 heterojunction structure.

2. The β-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar-blind ultraviolet communication according to claim 1, characterized in that, The β-Ga2O3 thin film layer was deposited on a sapphire substrate using plasma-enhanced chemical vapor deposition (PECVD), and a Yb2O3 thin film layer was prepared in a selected area above the β-Ga2O3 thin film layer using a sol-gel method. The two layers form a type II heterojunction structure. Subsequently, Ag electrodes were deposited on the β-Ga2O3 thin film layer and the Yb2O3 thin film layer using a thermal evaporation process.

3. The β-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar-blind ultraviolet communication according to claim 1, characterized in that, The sapphire substrate is a c-plane sapphire substrate with a thickness of 300~500μm and a polished surface with a surface roughness Ra≤0.5nm.

4. The β-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar-blind ultraviolet communication according to claim 1, characterized in that, The sapphire substrate and the β-Ga2O3 thin film layer have the same length × width, both being 1.0cm × 1.0cm to 2.0cm × 2.0cm, and the thickness of the β-Ga2O3 thin film layer is 0.1 to 2μm.

5. The β-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar-blind ultraviolet communication according to claim 1, characterized in that, The Yb2O3 thin film has a length × width of 0.5cm × 1.0cm to 1.0cm × 2.0cm and a thickness of 0.1 to 1.0μm.

6. The β-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar-blind ultraviolet communication according to claim 1, characterized in that, The Ag electrode is thermally deposited on both the β-Ga2O3 thin film layer and the Yb2O3 thin film layer, and the thickness of the Ag electrode is 50~100nm.

7. A method for preparing a β-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar-blind ultraviolet communication as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Sapphire substrate pretreatment: The sapphire substrate is ultrasonically cleaned with acetone, anhydrous ethanol, and deionized water for 10-20 minutes in sequence. After cleaning, most of the moisture is dried with high-purity nitrogen gas, and the substrate is placed in an oven at 100-150℃ to dry the remaining moisture. The purity of the high-purity nitrogen gas is ≥99.99%. Step 2: β-Ga2O3 thin film is deposited on the pretreated sapphire substrate using PECVD method. Liquid gallium metal with a purity ≥99.99% is used as gallium source, argon is used as carrier gas with a flow rate controlled at 80~100 sccm, oxygen is used as reactant gas with a flow rate controlled at 5~8 sccm, the deposition temperature is controlled at 750~1000℃, the RF power is controlled at 130~200W, and the deposition time is controlled at 35~60min. Step 3: Prepare Yb2O3 thin film using sol-gel method: Use a mask to cover a selected area of ​​the β-Ga2O3 thin film layer, use a pipette to pick up a certain amount of Yb2O3 precursor sol and spin-coat it onto the unmasked area of ​​the β-Ga2O3 thin film layer, dry at 100~150℃ for 10~20min, and then transfer the sample to a muffle furnace for high-temperature annealing in air atmosphere; Step 4: Prepare Ag electrodes using thermal evaporation: Using a mask, deposit Ag electrodes in the regions above the β-Ga2O3 thin film layer and Yb2O3 thin film layer respectively through thermal evaporation process.

8. The method for fabricating a β-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar-blind ultraviolet communication according to claim 7, characterized in that, In step three, the process parameters for preparing Yb2O3 thin films using the sol-gel method are as follows: using ytterbium nitrate hydrate Yb(NO3)3·5H2O with a purity ≥99.99% as a precursor, 2-methoxyethanol as a solvent, and citric acid as a chelating agent, and maintaining the temperature in a water bath at 60~80℃ for 2~4h; the spin-coating parameters are: spin-coating speed of 3000~6000r / min, spin-coating time of 30~60s, and the annealing temperature of the high-temperature annealing treatment is 500~750℃, the heating rate is 10℃ / min, and the annealing time is 1~4h.

9. The method for fabricating a β-Ga2O3 / Yb2O3 heterojunction self-driven detector for solar-blind ultraviolet communication according to claim 1, characterized in that, In step four, the process parameters for preparing Ag electrodes by thermal evaporation are as follows: Ag particles with a purity of ≥99.99% are used as the evaporation source, the evaporation current is 80~120A, and the evaporation time is 3~5min.

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