A flexible amorphous gallium oxide solar blind ultraviolet detector based on an asymmetric electrode structure and a preparation method and application thereof
By fabricating amorphous gallium oxide thin films and asymmetric interdigitated electrodes on flexible substrates, the challenges of flexibility and low power consumption in solar-blind ultraviolet detectors have been addressed, achieving self-powered and wearable characteristics, making them suitable for high-performance detection in complex curved environments.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SHANGHAI UNIV
- Filing Date
- 2026-02-27
- Publication Date
- 2026-07-07
AI Technical Summary
Existing solar-blind ultraviolet detectors are difficult to combine flexibility, low power consumption, and wearability, and cannot adapt to complex curved environments or achieve self-powered operation, thus limiting their application in field monitoring and wearable devices.
A flexible amorphous gallium oxide solar-blind ultraviolet detector with an asymmetric electrode structure achieves low-loss and high-efficiency carrier transport by fabricating amorphous gallium oxide thin films and asymmetric interdigitated electrodes on a flexible substrate and forming ohmic contacts using magnetron sputtering and electron beam evaporation. It also enables self-powered detection by autonomously separating electron-hole pairs under zero bias.
It achieves low-power detection with self-powered operation under zero bias, and the device can still work well in a bent state, making it suitable for wearable device applications. Moreover, the fabrication process is simple and low-cost, making it suitable for mass production.
Smart Images
Figure CN122349256A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of semiconductor device manufacturing technology, and in particular to a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure, its fabrication method, and its application. Background Technology
[0002] Sunlight contains abundant ultraviolet light, but the wavelengths of ultraviolet light in the 200-280 nm range are strongly absorbed by the Earth's ozone layer, almost completely blocking its path to the Earth's surface; this is known as solar-blind ultraviolet light. This characteristic allows solar-blind ultraviolet photodetectors to effectively avoid the strongest natural background interference from sunlight when detecting relevant signals, resulting in extremely high sensitivity and detection accuracy. Therefore, these detectors have important applications in key military and civilian fields, such as ozone layer monitoring, flame detection, medical imaging, ultraviolet communication, and missile early warning systems. In recent years, with the increasing application scenarios such as field monitoring, IoT nodes, and wearable devices, higher demands have been placed on the form and power consumption of detectors. These demands specifically require flexibility to adapt to complex curved surfaces, while simultaneously achieving low power consumption and even self-powered functionality to ensure ultra-long battery life. Against this backdrop, solar-blind ultraviolet detectors, combining high performance, low power consumption, and wearability, have been regarded as core optoelectronic technology devices for achieving continuous, real-time monitoring, demonstrating enormous application value. Summary of the Invention
[0003] The purpose of this invention is to provide a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure, its fabrication method, and its application. The solar-blind ultraviolet detector has the characteristics of self-powered operation, low power consumption, and flexibility, and is wearable.
[0004] The objective of this invention can be achieved through the following technical solutions: One objective of this invention is to provide a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure, characterized in that it includes a flexible substrate, an amorphous gallium oxide thin film layer disposed on the upper surface of the flexible substrate, and an asymmetric interdigitated electrode disposed on the upper surface of the amorphous gallium oxide thin film layer.
[0005] Preferably, the flexible substrate is treated with argon-oxygen plasma to obtain a substrate with stronger adhesion to the thin film, which can improve the performance under bending conditions.
[0006] Preferably, the flexible substrate is a flexible organic material substrate, and more preferably a PI (polyimide) flexible substrate.
[0007] Preferably, the asymmetric interdigitated electrode forms an ohmic contact with the amorphous gallium oxide thin film layer, and the width of the interface barrier between the two is significantly narrowed to a tunnelable range, so that the charge carriers can be transported between the electrode and the semiconductor with low loss and bidirectional high efficiency, and the current-voltage characteristics show a good linear ohmic relationship.
[0008] Preferably, the asymmetric interdigitated electrode includes either an asymmetric oxide interdigitated electrode or an asymmetric metal interdigitated electrode, wherein the asymmetric oxide interdigitated electrode includes an asymmetric BGZO interdigitated electrode, and the asymmetric metal interdigitated electrode includes an asymmetric Ti interdigitated electrode.
[0009] More preferably, the asymmetric interdigitated electrode includes a first interdigitated electrode group and a second interdigitated electrode group. The first interdigitated electrode group includes a first gate and a plurality of first interdigitated fingers evenly spaced thereon. The second interdigitated electrode group includes a second gate and a plurality of second interdigitated fingers evenly spaced thereon. The first gate and the second gate are arranged in parallel, and the plurality of first interdigitated fingers and the plurality of second interdigitated fingers are arranged alternately and staggered. The interdigitated fingers of the first interdigitated fingers and the second interdigitated fingers are different in width.
[0010] Preferably, the asymmetric interdigitated electrode has 1 to 10 interdigitated pairs, an interdigitated width of 0.1 to 1 mm, an interdigitated spacing of 0.1 to 1 mm, an interdigitated length of 5 to 15 mm, and a gate width of 0.1 to 10 mm.
[0011] More preferably, the asymmetric BGZO interdigitated electrode refers to an asymmetric boron-gallium co-doped transparent ZnO interdigitated electrode.
[0012] More preferably, the thickness of the asymmetric BGZO interdigitated electrode is 100 nm.
[0013] More preferably, the thickness of the asymmetric Ti interdigitated electrode is 50 nm.
[0014] Preferably, the thickness of the flexible substrate is 20~250 μm, the thickness of the amorphous gallium oxide thin film layer is 50~500 nm, and the thickness of the asymmetric interdigitated electrode is 20~200 nm.
[0015] The second objective of this invention is to provide a method for fabricating a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure, comprising the following steps: S1. Flexible substrate treatment: Clean the flexible substrate and then perform argon-oxygen plasma treatment; S2. Preparation of amorphous gallium oxide thin film: An amorphous gallium oxide thin film is sputtered on the flexible substrate treated by S1 using a mask and magnetron sputtering. S3. Fabrication of asymmetric interdigitated electrodes: Asymmetric interdigitated electrodes are fabricated on the amorphous gallium oxide thin film layer obtained in step S2 to obtain the solar-blind ultraviolet detector.
[0016] Preferably, in step S1, the cleaning refers to first cleaning the surface of the flexible substrate with a neutral cleaning agent, then ultrasonically cleaning it with ethanol, methanol and deionized water for 1 to 30 minutes respectively to remove impurities from the surface of the flexible substrate, and then drying it with high-purity nitrogen to obtain a clean and dry flexible substrate.
[0017] More preferably, in step S1, the neutral cleaning agent is a detergent whose main component includes sodium alkylbenzene sulfonate.
[0018] More preferably, in step S1, the ultrasonic cleaning time is 5 minutes.
[0019] Preferably, in step S1, the argon-oxygen plasma treatment refers to sending a clean and dry flexible substrate into a magnetron sputtering pretreatment chamber, evacuating it, and then introducing argon gas with a flow rate of 1~50 sccm and oxygen gas with a flow rate of 1~50 sccm; setting the sputtering power to 5~100 W and sputtering for 1~69 min.
[0020] More preferably, in step S1, the argon flow rate is 24.5 sccm and the oxygen flow rate is 10.5 sccm.
[0021] Preferably, in step S2, the magnetron sputtering uses a high-purity Ga2O3 ceramic target with a purity higher than 99.99%, and the base vacuum of the magnetron sputtering is 1.33 × 10⁻⁶. -5 ~1.33×10 -4 The magnetron sputtering is performed under an argon atmosphere with a gas flow rate in the range of 10~40 sccm, a sputtering pressure of 0.1~1 Pa, and a sputtering power of 10~250 W. The sputtering process involves pre-sputtering for 1~30 min, followed by opening the baffle to start the formal sputtering, which lasts for 10~150 min. After sputtering is completed, the amorphous gallium oxide thin film layer is obtained.
[0022] More preferably, in step S2, the argon gas flow rate is 30 sccm and the sputtering power is 150 W.
[0023] More preferably, in step S2, the tray rotation speed of the magnetron sputtering is ≤5 rad / min.
[0024] More preferably, in step S2, after 10 minutes of pre-sputtering, the baffle is opened to start the formal sputtering, and after the sputtering is completed, an amorphous gallium oxide thin film layer (a-Ga2O3 thin film layer) with a thickness of 250 nm is obtained.
[0025] Preferably, step S3 specifically involves: using a mask, directly preparing the asymmetric interdigitated electrode by magnetron sputtering or electron beam evaporation; or without using a mask, first preparing the electrode layer by magnetron sputtering or electron beam evaporation, and then preparing the asymmetric interdigitated electrode by photolithography.
[0026] More preferably, in step S3, when the asymmetric oxide interdigitated electrode is an asymmetric BGZO interdigitated electrode, the target material used is a ZnO ceramic target material co-doped with 1.8 wt% boron and 0.2 wt% gallium.
[0027] More preferably, in step S3, when the asymmetric metal interdigitated electrode is an asymmetric Ti interdigitated electrode, a titanium target is selected.
[0028] More preferably, in step S3, the mask is a mask with asymmetric interdigitated electrode dimensions.
[0029] More preferably, the fabrication method of the flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure includes the following steps: (1) Substrate cleaning: Flexible organic materials were selected as substrates. Before growing the bottom electrode, the substrate surface was first cleaned with a neutral cleaning agent, and then ultrasonically cleaned with ethanol, methanol, and deionized water for 1–30 min respectively to remove impurities from the substrate surface. The substrate was then dried with high-purity nitrogen to obtain a clean and dry substrate. The cleaned substrate was then placed into a magnetron sputtering pretreatment chamber. After the sputtering chamber was evacuated, plasma treatment was performed: argon gas and oxygen gas with a flow rate of 1–50 sccm were introduced; the sputtering power was set to 5–100 W, and sputtering was performed for 1–69 min to obtain a substrate with stronger adhesion to the thin film, ready for use. (2) Preparation of a-Ga2O3 thin film layer: The processed substrate is sent into the magnetron sputtering cavity. The target material is selected as a high-purity Ga2O3 ceramic target with a purity of 99.99% or higher. The substrate obtained in step (1) is placed on the sample stage. After the sputtering cavity is evacuated, argon gas with a flow rate of 10~40 sccm is introduced. The sputtering pressure and sputtering power are set to 0.1~1 Pa and 10~250 W respectively. After pre-sputtering for 1~30 min, the baffle is opened to start the formal sputtering. After the sputtering is completed, an a-Ga2O3 thin film layer is obtained.
[0030] (3) Fabrication of asymmetric interdigitated electrodes: (a) Fabrication of asymmetric oxide interdigitated electrodes: Oxide interdigitated electrodes are directly fabricated on the surface of an a-Ga2O3 thin film using magnetron sputtering, electron beam evaporation, or other methods with a metal mask, or asymmetric oxide interdigitated electrodes are obtained by photolithography after fabricating an electrode layer. The electrode material is a transparent conductive oxide such as boron-gallium co-doped ZnO (BGZO). Asymmetric BGZO interdigitated electrodes with interdigitated widths of 0.1~1 mm and gate widths of 0.1~10 mm are obtained.
[0031] (b) Fabrication of asymmetric interdigitated metal electrodes: Metal interdigitated electrodes are directly fabricated on the surface of an a-Ga2O3 thin film using magnetron sputtering, electron beam evaporation, or other methods with a metal mask, or metal interdigitated electrodes are obtained by photolithography after fabricating an electrode layer. The electrode material is titanium, etc., to prepare asymmetric metal interdigitated electrodes with interdigitated width of 0.1~1 mm and gate width of 0.1~10 mm.
[0032] The third objective of this invention is to provide an application of the flexible amorphous gallium oxide solar-blind ultraviolet detector based on the aforementioned asymmetric electrode structure in the field of ultraviolet detection.
[0033] This invention relates to a solar-blind ultraviolet photodetector based on a planar metal-semiconductor-metal (MSM) structure. The fabrication process is simple, facilitating low-cost, large-scale manufacturing and system integration. Furthermore, its planar electrode structure results in low parasitic capacitance, making it highly suitable for high-frequency applications. Simultaneously, the MSM-type solar-blind ultraviolet photodetector based on an asymmetric electrode structure generates photogenerated carriers in the semiconductor layer after absorbing ultraviolet light. Due to the different sizes of the two sets of interdigitated electrodes, their effective contact areas differ, leading to different collection efficiencies for photogenerated carriers. This creates a carrier concentration gradient, enabling the construction of an internal electric field within the device. This allows for the autonomous separation of electron-hole pairs, enabling movement towards the two electrodes and achieving self-powered detection under zero bias.
[0034] Currently, Ga2O3, as a typical ultrawide bandgap semiconductor material, has a bandgap of 4.4-5.3 eV and a Baliga value as high as 3214.1. It possesses advantages such as high breakdown electric field strength (8 MV / cm), excellent chemical stability, thermal stability, and radiation resistance, and is considered one of the ideal materials for fabricating solar-blind ultraviolet photodetectors. At the same time, Ga2O3 is a direct bandgap semiconductor material. Its wide bandgap allows it to have a high transmittance of over 80% in the visible light region, and it has excellent absorption performance in the ultraviolet light band (especially in the solar-blind ultraviolet region below 280 nm), with the absorption edge located approximately around 250 nm. Therefore, it is often used to fabricate ultraviolet photodetectors, field-effect transistors, Schottky diodes, and other devices, showing significant application potential in fields such as national defense, aerospace, microwave communications, and rail transportation.
[0035] There are five isomers of Ga2O3: α-Ga2O3, β-Ga2O3, γ-Ga2O3, δ-Ga2O3, and ε-Ga2O3. In addition, there is amorphous Ga2O3 (a-Ga2O3), which can usually be obtained without high temperatures and has a large number of defects and oxygen vacancies, thus trapping holes and preventing carrier recombination, making it advantageous for use in flexible photodetectors.
[0036] The main methods for fabricating asymmetric electrodes include magnetron sputtering and electron beam evaporation deposition. Magnetron sputtering is suitable for oxide electrodes, while electron beam evaporation deposition is suitable for metal electrodes. The main methods for fabricating α-Ga₂O₃ thin films include magnetron sputtering, metal-organic chemical vapor deposition, pulsed laser deposition, and molecular beam epitaxy. Comparing various methods, magnetron sputtering is simple to operate, can achieve large-area room-temperature deposition, and is suitable for flexible substrates. The prepared materials exhibit strong adhesion and a relatively uniform structure.
[0037] In summary, this invention employs magnetron sputtering to prepare an a-Ga2O3 thin film on a flexible substrate, and uses electron beam evaporation or magnetron sputtering to prepare interdigitated electrodes of different sizes to achieve an asymmetric electrode structure. This enables the fabrication of a flexible a-Ga2O3-based solar-blind ultraviolet detector based on the asymmetric electrode structure. The solar-blind ultraviolet detector has self-powered characteristics and flexible performance, and can still work well in a bent state.
[0038] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention provides a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure, its preparation method and application. The solar-blind ultraviolet detector is prepared by magnetron sputtering. An appropriate sputtering power is selected to prepare an a-Ga2O3 thin film layer on a flexible substrate. Then, an interdigitated electrode of different sizes is prepared on the a-Ga2O3 thin film layer by electron beam evaporation or magnetron sputtering to realize an asymmetric electrode structure. The solar-blind ultraviolet detector finally prepared has the characteristics of self-powered, low power consumption and flexibility, and has wearable characteristics.
[0039] (2) The solar-blind ultraviolet detector of the present invention is based on an asymmetric interdigitated electrode structure. Compared with the symmetric electrode structure, the asymmetric structure of the present invention has different effective contact areas due to the different sizes of the two sets of interdigitated electrodes. This results in different collection efficiencies of the two sets of electrodes for photogenerated carriers, thereby generating a carrier concentration gradient. This can form a built-in electric field inside the device, autonomously separating electron-hole pairs and realizing self-powered detection under zero bias voltage. Under 0V, 254nm ultraviolet light irradiation, the photo-dark current ratio of the device reaches 10. 4 This improves the electrical performance of the device.
[0040] (3) The amorphous gallium oxide (a-Ga2O3)-based solar-blind ultraviolet detector with an asymmetric interdigitated electrode structure of the present invention exhibits an increase in the photoluminescence-dark-current ratio as the area ratio of the two sets of interdigitated electrodes increases under 0V and 254 nm illumination, reaching a photoluminescence-dark-current ratio of 10. 4 The asymmetric structure significantly enhances the self-powered performance.
[0041] (4) The present invention is based on the growth of amorphous gallium oxide (a-Ga2O3)-based solar-blind ultraviolet detector with asymmetric electrode structure on a flexible substrate. The solar-blind ultraviolet detector has the characteristics of self-powered operation and good operation in a bent state. It can still maintain about 80% of the peak current at 0V and 70° bending. The device is simple to process, easy to carry and wearable, and can be applied to the field of wearable devices.
[0042] (5) The preparation process of magnetron sputtering used in this invention is simpler to operate, lower in cost, can be prepared on a large area, and has high feasibility for batch growth compared with other growth processes. Attached Figure Description
[0043] Figure 1 This is a schematic diagram of the asymmetric electrode mask in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the asymmetric electrode mask in embodiments 2 and 4 of the present invention; Figure 3 This is a schematic diagram of the asymmetric electrode mask in Embodiment 3 of the present invention; Figure 4 This is a schematic diagram illustrating the fabrication process and device structure of the solar-blind ultraviolet detector of the present invention; Figure 5 The dark current of the detector in Example 4 and the photo-dark current curves under 254 nm ultraviolet light irradiation are shown. Figure 6 The dark current of detectors with electrodes of different sizes and the photo-dark current curves under 254 nm ultraviolet light illumination are shown in the inset. The photo-dark current ratio of the detector is shown in the inset. Figure 7 The image shows the flexible time response curve of the detector in Example 4 under 0V and 254nm illumination. Detailed Implementation
[0044] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.
[0045] Unless otherwise specified, the reagents, methods, instruments, and equipment used in this invention are conventional in the art. Unless otherwise specified, the reagents and materials used in the following examples are all commercially available.
[0046] A flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure includes a flexible substrate, an amorphous gallium oxide thin film layer disposed on the upper surface of the flexible substrate, and an asymmetric interdigitated electrode disposed on the upper surface of the amorphous gallium oxide thin film layer, wherein the asymmetric interdigitated electrode and the amorphous gallium oxide thin film layer form an ohmic contact.
[0047] The flexible substrate is treated with argon-oxygen plasma and includes a PI flexible substrate. The asymmetric interdigitated electrode includes either an asymmetric oxide interdigitated electrode or an asymmetric metal interdigitated electrode. The asymmetric oxide interdigitated electrode includes an asymmetric BGZO interdigitated electrode, and the asymmetric metal interdigitated electrode includes an asymmetric Ti interdigitated electrode. The asymmetric interdigitated electrode has 1 to 10 interdigital pairs, an interdigital width of 0.1 to 1 mm, an interdigital spacing of 0.1 to 1 mm, an interdigital length of 5 to 15 mm, and a gate width of 0.1 to 10 mm. The flexible substrate has a thickness of 20 to 250 μm, the amorphous gallium oxide thin film has a thickness of 50 to 500 nm, and the asymmetric interdigitated electrode has a thickness of 20 to 200 nm.
[0048] The fabrication method of this flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure includes the following steps: S1. Flexible Substrate Processing: The flexible substrate is cleaned and then subjected to argon-oxygen plasma treatment. Cleaning involves first cleaning the surface of the flexible substrate with a neutral cleaning agent, then sequentially ultrasonically cleaning it with ethanol, methanol, and deionized water for 1-30 minutes each to remove impurities. The substrate is then dried with high-purity nitrogen to obtain a clean and dry flexible substrate. Argon-oxygen plasma treatment involves placing the clean and dry flexible substrate into a magnetron sputtering pretreatment chamber, evacuating it, and then introducing argon and oxygen gas at a flow rate of 1-50 sccm. The sputtering power is set to 5-100 W, and sputtering is performed for 1-69 minutes. S2. Fabrication of amorphous gallium oxide thin film: An amorphous gallium oxide thin film was sputtered onto the flexible substrate treated in S1 using a mask and magnetron sputtering. The magnetron sputtering employed a high-purity Ga2O3 ceramic target with a purity exceeding 99.99%, and the base vacuum level for magnetron sputtering was 1.33 × 10⁻⁶. -5 ~1.33×10 -4The magnetron sputtering was performed under an argon atmosphere with a gas flow rate of 10–40 sccm, a sputtering pressure of 0.1–1 Pa, and a sputtering power of 10–250 W. The sputtering process involved pre-sputtering for 1–30 min, followed by opening the baffle to begin the formal sputtering, which lasted for 10–150 min. After sputtering, an amorphous gallium oxide thin film was obtained. S3. Fabrication of asymmetric interdigitated electrodes: Asymmetric interdigitated electrodes are fabricated on the amorphous gallium oxide thin film layer obtained in step S2. The specific steps are as follows: using a mask, the asymmetric interdigitated electrodes are directly fabricated by magnetron sputtering or electron beam evaporation; or without using a mask, the electrode layer is first fabricated by magnetron sputtering or electron beam evaporation, and then the asymmetric interdigitated electrodes are fabricated by photolithography, finally obtaining a solar-blind ultraviolet detector. In the following embodiments, an a-Ga2O3 thin film layer was prepared by radio frequency magnetron sputtering, by selecting, for example... Figures 1-3 The asymmetric electrode masks of different sizes shown were used to fabricate asymmetric interdigitated electrodes via radio frequency magnetron sputtering or electron beam evaporation, thus realizing the fabrication of a flexible a-Ga2O3-based solar-blind ultraviolet detector with an asymmetric electrode structure. The complete process flow is as follows: Figure 4 As shown. The thin film preparation method of this invention is simple to operate, low in cost, and has significant effects. The high-performance, portable, wearable solar-blind ultraviolet detector obtained by this invention can be better applied in ultraviolet detection and other fields.
[0049] Example 1: This embodiment provides a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure. The fabrication method includes the following steps: (1) Substrate treatment: A PI flexible substrate was selected and cut to a size of 19.5 mm × 19.5 mm with a thickness of 0.125 mm. The substrate surface was first cleaned with a neutral cleaning agent, then ultrasonically cleaned for 5 min each with ethanol, methanol, and deionized water to remove impurities. The substrate was then dried with high-purity nitrogen to obtain a clean and dry substrate. The cleaned substrate was then placed in a magnetron sputtering pretreatment chamber. After evacuating the sputtering chamber, argon gas at a flow rate of 24.5 sccm and oxygen gas at a flow rate of 10.5 sccm were introduced. The sputtering power was set to 50 W, and after sputtering for 2 min, a substrate with stronger adhesion to the thin film was obtained and ready for use. (2) Preparation of a-Ga2O3 thin film layer: The processed substrate was sent into the magnetron sputtering cavity. The target material was selected as a high-purity Ga2O3 ceramic target with a purity of 99.99% or higher. The substrate obtained in step (1) was placed on the sample stage. After the sputtering cavity was evacuated, argon gas with a flow rate of 30 sccm was introduced. The sputtering pressure and sputtering power were set to 0.8 Pa and 150 W, respectively. After pre-sputtering for 10 min, the baffle was opened to start the formal sputtering. The sputtering time was 125 min. After the sputtering was completed, an a-Ga2O3 thin film layer with a thickness of 250 nm was obtained. (3) Fabrication of asymmetric interdigitated electrodes: A substrate with a Ga2O3 thin film layer is placed into a magnetron sputtering cavity. A ZnO ceramic target co-doped with boron (1.8 wt%) and gallium (0.2 wt%) is selected. A metal interdigitated electrode mask is selected, and the mask is first placed over the a-Ga2O3 thin film surface obtained in step (2), and then placed on the sample stage. Figure 1 As shown, the mask corresponds to an asymmetric interdigitated electrode structure, with the widths of the two sets of interdigitated fingers being 0.5 mm and 0.7 mm, respectively, and the gate width of each set of interdigitated fingers being 2.5 mm. The two sets of interdigitated fingers are arranged alternately. After the sputtering chamber is evacuated, argon gas with a flow rate of 30 sccm is introduced. The sputtering pressure and sputtering power are set to 0.8 Pa and 150 W, respectively. After pre-sputtering for 10 min, the baffle is opened to start the formal sputtering. After the sputtering is completed, a BGZO thin film with a thickness of 100 nm is obtained.
[0050] Example 2: This embodiment provides a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure. The fabrication method includes the following steps: (1) Substrate treatment: A PI flexible substrate was selected and cut to a size of 19.5 mm × 19.5 mm with a thickness of 0.125 mm. The substrate surface was first cleaned with a neutral cleaning agent, then ultrasonically cleaned for 5 min each with ethanol, methanol, and deionized water to remove impurities. The substrate was then dried with high-purity nitrogen to obtain a clean and dry substrate. The cleaned substrate was then placed in a magnetron sputtering pretreatment chamber. After evacuating the sputtering chamber, argon gas at a flow rate of 24.5 sccm and oxygen gas at a flow rate of 10.5 sccm were introduced. The sputtering power was set to 50 W, and after sputtering for 2 min, a substrate with stronger adhesion to the thin film was obtained and ready for use. (2) Preparation of a-Ga2O3 thin film layer: The processed substrate was sent into the magnetron sputtering cavity. The target material was selected as a high-purity Ga2O3 ceramic target with a purity of 99.99% or higher. The substrate obtained in step (1) was placed on the sample stage. After the sputtering cavity was evacuated, argon gas with a flow rate of 30 sccm was introduced. The sputtering pressure and sputtering power were set to 0.8 Pa and 150 W, respectively. After pre-sputtering for 10 min, the baffle was opened to start the formal sputtering. The sputtering time was 125 min. After the sputtering was completed, an a-Ga2O3 thin film layer with a thickness of 250 nm was obtained. (3) Fabrication of asymmetric interdigitated electrodes: A substrate with an a-Ga2O3 thin film layer is placed into a magnetron sputtering cavity. A ZnO ceramic target co-doped with boron (1.8 wt%) and gallium (0.2 wt%) is selected. A metal interdigitated electrode mask is selected, and the mask is first placed over the a-Ga2O3 thin film surface obtained in step (2), and then placed on the sample stage. Figure 2 As shown, the mask corresponds to an asymmetric interdigitated electrode structure, with the widths of the two sets of interdigitated fingers being 0.5 mm and 0.9 mm, respectively, and the gate width of each set of interdigitated fingers being 2.5 mm. The two sets of interdigitated fingers are arranged alternately. After the sputtering chamber is evacuated, argon gas with a flow rate of 30 sccm is introduced. The sputtering pressure and sputtering power are set to 0.8 Pa and 150 W, respectively. After pre-sputtering for 10 min, the baffle is opened to start the formal sputtering. After the sputtering is completed, a BGZO thin film with a thickness of 100 nm is obtained.
[0051] Example 3: This embodiment provides a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure. The fabrication method includes the following steps: (1) Substrate treatment: A PI flexible substrate was selected and cut to a size of 19.5 mm × 19.5 mm with a thickness of 0.125 mm. The substrate surface was first cleaned with a neutral cleaning agent, then ultrasonically cleaned for 5 min each with ethanol, methanol, and deionized water to remove impurities. The substrate was then dried with high-purity nitrogen to obtain a clean and dry substrate. The cleaned substrate was then placed in a magnetron sputtering pretreatment chamber. After evacuating the sputtering chamber, argon gas at a flow rate of 24.5 sccm and oxygen gas at a flow rate of 10.5 sccm were introduced. The sputtering power was set to 50 W, and after sputtering for 2 min, a substrate with stronger adhesion to the thin film was obtained and ready for use. (2) Preparation of a-Ga2O3 thin film layer: The processed substrate was sent into the magnetron sputtering cavity. The target material was selected as a high-purity Ga2O3 ceramic target with a purity of 99.99% or higher. The substrate obtained in step (1) was placed on the sample stage. After the sputtering cavity was evacuated, argon gas with a flow rate of 30 sccm was introduced. The sputtering pressure and sputtering power were set to 0.8 Pa and 150 W, respectively. After pre-sputtering for 10 min, the baffle was opened to start the formal sputtering. The sputtering time was 125 min. After the sputtering was completed, an a-Ga2O3 thin film layer with a thickness of 250 nm was obtained. (3) Fabrication of asymmetric interdigitated electrodes: A substrate with an a-Ga2O3 thin film layer is placed into a magnetron sputtering cavity. A ZnO ceramic target co-doped with boron (1.8 wt%) and gallium (0.2 wt%) is selected. A metal interdigitated electrode mask is selected, and the mask is first placed over the a-Ga2O3 thin film surface obtained in step (2), and then placed on the sample stage. Figure 3 As shown, the mask corresponds to an asymmetric interdigitated electrode structure, with the widths of the two sets of interdigitated fingers being 0.7 mm and 0.9 mm, respectively, and the gate width of each set of interdigitated fingers being 2.5 mm. The two sets of interdigitated fingers are arranged alternately. After the sputtering chamber is evacuated, argon gas with a flow rate of 30 sccm is introduced. The sputtering pressure and sputtering power are set to 0.8 Pa and 150 W, respectively. After pre-sputtering for 10 min, the baffle is opened to start the formal sputtering. After the sputtering is completed, a BGZO film with a thickness of 100 nm is obtained.
[0052] Example 4: This embodiment provides a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure. The fabrication method includes the following steps: (1) Substrate treatment: A PI flexible substrate was selected and cut to a size of 19.5 mm × 19.5 mm with a thickness of 0.125 mm. The substrate surface was first cleaned with a neutral cleaning agent, then ultrasonically cleaned for 5 min each with ethanol, methanol, and deionized water to remove impurities. The substrate was then dried with high-purity nitrogen to obtain a clean and dry substrate. The cleaned substrate was then placed in a magnetron sputtering pretreatment chamber. After evacuating the sputtering chamber, argon gas at a flow rate of 24.5 sccm and oxygen gas at a flow rate of 10.5 sccm were introduced. The sputtering power was set to 50 W, and after sputtering for 2 min, a substrate with stronger adhesion to the thin film was obtained and ready for use. (2) Preparation of a-Ga2O3 thin film layer: The processed substrate was sent into the magnetron sputtering cavity. The target material was selected as a high-purity Ga2O3 ceramic target with a purity of 99.99% or higher. The substrate obtained in step (1) was placed on the sample stage. After the sputtering cavity was evacuated, argon gas with a flow rate of 30 sccm was introduced. The sputtering pressure and sputtering power were set to 0.8 Pa and 150 W, respectively. After pre-sputtering for 10 min, the baffle was opened to start the formal sputtering. The sputtering time was 125 min. After the sputtering was completed, an a-Ga2O3 thin film with a thickness of 250 nm was obtained. (3) Fabrication of asymmetric interdigitated electrodes: The sample with the a-Ga2O3 thin film layer is sent into the magnetron sputtering cavity, and a titanium target is selected; a metal interdigitated electrode mask is selected, and the mask is first placed over the a-Ga2O3 thin film surface obtained in step (2), and then placed on the sample stage; Figure 2 As shown, the mask corresponds to an asymmetric interdigitated electrode structure, with the widths of the two sets of interdigitated fingers being 0.5 mm and 0.9 mm, respectively, and the gate width of each set of interdigitated fingers being 2.5 mm. The two sets of interdigitated fingers are arranged in an alternating pattern. After the cavity is evacuated, the electron gun beam current is adjusted to 60 mA and the baffle is opened to start evaporation. After evaporation is completed, a titanium thin film with a thickness of 50 nm is obtained.
[0053] Figure 5 The figures show the relevant performance curves of the flexible solar-blind ultraviolet detector in Embodiment 4 of the present invention. Figure 6 The figures show the dark current curves for the detector with different electrode sizes and the photo-dark current curves under 254 nm ultraviolet light illumination. As can be seen from the figure, under 0 V and 254 nm ultraviolet light illumination, the photo-dark current ratio of the device reaches 10. 4 Furthermore, the ratio of light to dark current of the device increases with the increase of the area ratio of the two sets of interdigitated electrodes (this ratio specifically refers to the ratio of the larger of the two to the smaller of the two, i.e., a quantitative indicator of area difference). Figure 7 The figure shows the flexible time response curve of the detector under 0V and 254nm illumination. As can be seen from the figure, it can still maintain about 80% of the peak current when bent at 70°.
[0054] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.
Claims
1. A flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure, characterized in that, It includes a flexible substrate, on the upper surface of which an amorphous gallium oxide thin film layer is disposed, and on the upper surface of which an asymmetric interdigitated electrode is disposed.
2. The flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure according to claim 1, characterized in that, The flexible substrate is treated with argon-oxygen plasma, and the flexible substrate includes a PI flexible substrate.
3. The flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure according to claim 1, characterized in that, The asymmetric interdigitated electrode includes either an asymmetric oxide interdigitated electrode or an asymmetric metal interdigitated electrode. The asymmetric oxide interdigitated electrode includes an asymmetric BGZO interdigitated electrode, and the asymmetric metal interdigitated electrode includes an asymmetric Ti interdigitated electrode.
4. The flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure according to claim 1, characterized in that, The asymmetric interdigitated electrode has 1 to 10 interdigitated pairs, an interdigitated width of 0.1 to 1 mm, an interdigitated spacing of 0.1 to 1 mm, an interdigitated length of 5 to 15 mm, and a gate width of 0.1 to 10 mm.
5. A flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure according to claim 1, characterized in that, The thickness of the flexible substrate is 20~250 μm, the thickness of the amorphous gallium oxide thin film layer is 50~500 nm, and the thickness of the asymmetric interdigitated electrode is 20~200 nm.
6. A method for fabricating a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure as described in any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Flexible substrate treatment: Clean the flexible substrate and then perform argon-oxygen plasma treatment; S2. Preparation of amorphous gallium oxide thin film: An amorphous gallium oxide thin film is sputtered on the flexible substrate treated by S1 using a mask and magnetron sputtering. S3. Fabrication of asymmetric interdigitated electrodes: Asymmetric interdigitated electrodes are fabricated on the amorphous gallium oxide thin film layer obtained in step S2 to obtain the solar-blind ultraviolet detector.
7. The method for fabricating a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure according to claim 6, characterized in that, In step S1, the cleaning refers to first cleaning the surface of the flexible substrate with a neutral cleaning agent, then ultrasonically cleaning it with ethanol, methanol and deionized water for 1 to 30 minutes respectively to remove impurities from the surface of the flexible substrate, and then drying it with high-purity nitrogen to obtain a clean and dry flexible substrate. The argon-oxygen plasma treatment refers to sending a clean and dry flexible substrate into a magnetron sputtering pretreatment chamber, evacuating it, and then introducing argon gas at a flow rate of 1~50 sccm and oxygen gas at a flow rate of 1~50 sccm; setting the sputtering power to 5~100W and sputtering for 1~69min.
8. The method for fabricating a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure according to claim 6, characterized in that, In step S2, the magnetron sputtering uses a high-purity Ga2O3 ceramic target with a purity higher than 99.99%, and the base vacuum of the magnetron sputtering is 1.33 × 10⁻⁶. -5 ~1.33×10 -4 Pa, the magnetron sputtering is performed in an argon atmosphere, the gas flow rate of the argon atmosphere is in the range of 10~40 sccm, the sputtering pressure is 0.1~1 Pa, and the sputtering power is 10~250 W; The sputtering process involves pre-sputtering for 1-30 minutes, followed by opening the baffle to begin formal sputtering, which takes 10-150 minutes. After sputtering is complete, the amorphous gallium oxide thin film layer is obtained.
9. The method for fabricating a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure according to claim 6, characterized in that, The specific steps of step S3 are as follows: using a mask, the asymmetric interdigitated electrode is directly prepared by magnetron sputtering or electron beam evaporation; or without using a mask, the electrode layer is first prepared by magnetron sputtering or electron beam evaporation, and then the asymmetric interdigitated electrode is prepared by photolithography.
10. The application of a flexible amorphous gallium oxide solar-blind ultraviolet detector based on an asymmetric electrode structure as described in any one of claims 1 to 5 in the field of ultraviolet detection.