Gallium oxide-based flexible self-powered solar-blind ultraviolet detector and preparation method thereof

Abstract

The invention discloses a flexible self-powered solar-blind ultraviolet detector based on gallium oxide and a preparation method thereof. The flexible self-powered solar-blind ultraviolet detector is specially designed to be used for efficient and low-power-consumption ultraviolet light detection in a complex environment. The detector is characterized by the design of the asymmetric electrode and the aluminum oxide passivation layer. The device specifically comprises a first metal electrode and a second metal electrode which are located on a gallium oxide thin film and can respectively form Schottky contact and ohmic contact through different technological processes and a patterned passivation layer according to different materials and sizes of the first metal electrode and the second metal electrode, so that the photoelectric property is effectively improved. The first metal electrode realizes high-quality ohmic contact by increasing the contact area, selecting materials and adopting an annealing process. And the second metal electrode realizes Schottky contact and improves the contact barrier through material selection and introduction of a passivation layer. The asymmetric electrode design can enhance a built-in electric field and effectively realize separation of photon-generated carriers, so that self power supply is better realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of photoelectric detectors, and in particular relates to a gallium oxide-based flexible self-powered solar-blind ultraviolet detector and a preparation method thereof. Background Art

[0002] Solar-blind UV detectors are naturally low-noise and highly sensitive because they are not affected by sunlight, and are widely used in science, military, and industry. Gallium oxide is an ideal UV detection material with a bandgap of up to 4.9eV, which naturally fits the solar-blind band and has broad application prospects in the field of UV detectors.

[0003] The advantage of flexible photodetectors is their adaptability. Since the material itself has good bending properties, the detector can effectively fit non-planar structures, increasing the diversity of detector usage scenarios. Self-powered photodetectors use the photovoltaic effect and can operate without external power, and are often used in low-power sensing applications. Flexible and self-powered day-blind UV detectors have unique flexibility and passive characteristics. They still perform well even in scenarios where the detector is difficult to power, the working environment is complex, and the installation and layout are difficult, including remote area environmental monitoring, temporary installation, and emergency response.

[0004] Self-powered photodetectors based on Schottky junctions can be prepared at lower temperatures and are very suitable for the preparation of flexible devices. Self-powered photodetectors based on heterojunctions, on the other hand, need to be prepared at higher process temperatures and have poor feasibility on flexible, high-temperature-sensitive substrate materials. Therefore, self-powered ultraviolet detectors based on Schottky junctions have great advantages in flexible applications. The current development of gallium oxide-based flexible self-powered ultraviolet detectors is generally based on heterojunctions to achieve self-powered characteristics, and cannot achieve a good balance in terms of manufacturing process, photoelectric performance, long-term working stability, and adaptability to complex environments. Therefore, it is necessary to further design Schottky flexible self-powered gallium oxide solar-blind ultraviolet detectors that are more efficient, more stable, more widely applicable, and have simpler preparation processes to meet the application of solar-blind ultraviolet detection in the field of emerging technologies. Summary of the invention

[0005] In order to overcome the current inadequate problems regarding flexible and self-powered applications in solar-blind ultraviolet detection, the purpose of the present invention is to provide a gallium oxide-based flexible self-powered solar-blind ultraviolet detector and a preparation method thereof, which can be used for low-power ultraviolet detection in complex environments.

[0006] In order to achieve the above object, the present invention adopts the following technical solution: A gallium oxide-based flexible self-powered day-blind ultraviolet detector comprises a substrate layer, on which a gallium oxide film is prepared; a first metal electrode is prepared on the gallium oxide film; a passivation layer is prepared on the gallium oxide film; a contact surface between the first metal electrode and the gallium oxide film is complementary in shape to the passivation layer; the first metal electrode and the passivation layer are both in direct contact with the gallium oxide film; a second metal electrode is prepared on the passivation layer; and the second metal electrode and the first metal electrode form an interdigitated electrode structure.

[0007] Furthermore, an ohmic contact is formed between the first metal electrode and the gallium oxide film; and a Schottky contact is formed between the second metal electrode and the gallium oxide film.

[0008] Furthermore, a ratio of a contact area between the first metal electrode and the gallium oxide film to a contact area between the second metal electrode and the gallium oxide film is greater than or equal to 2.

[0009] Furthermore, the substrate layer is made of a flexible material capable of withstanding a high temperature of 400 degrees Celsius.

[0010] Furthermore, the passivation layer is an aluminum oxide film with a thickness less than or equal to 5 nm.

[0011] A method for preparing a gallium oxide-based flexible self-powered solar-blind ultraviolet detector comprises the following steps: S1, depositing a gallium oxide thin film on a substrate layer; S2, depositing aluminum oxide on the gallium oxide film, and then patterning the aluminum oxide layer to obtain a passivation layer; S3, depositing metal on the gallium oxide film, patterning it, and then annealing it to form an ohmic contact to obtain a first metal electrode; the first metal electrode forms an ohmic contact with the gallium oxide film, and does not contact the passivation layer except for the edge overlap area; S4, depositing metal on the passivation layer and patterning it to obtain a second metal electrode that forms an interdigitated shape with the first metal electrode; the second metal electrode forms a Schottky contact with the gallium oxide film.

[0012] Furthermore, in step S1, the method of depositing the gallium oxide film includes but is not limited to magnetron sputtering and atomic layer deposition; the thickness of the gallium oxide film is between 200 nm and 600 nm.

[0013] Furthermore, in step S2, the passivation layer material is aluminum oxide, the method of depositing the aluminum oxide layer is atomic layer deposition, and the patterning method is etching or stripping process.

[0014] Furthermore, in step S3, the deposited metal is titanium, aluminum, silver or a composite metal laminate material, and the preparation method of the titanium, aluminum, silver or composite metal laminate material includes but is not limited to magnetron sputtering and electron beam evaporation; the patterning method is an etching or stripping process; the annealing temperature is 300~400℃; the annealing time is 30~120 minutes; the first metal electrode is in direct contact with the gallium oxide film, and does not contact the passivation layer except for the edge overlap area.

[0015] Furthermore, in step S4, the deposited metal is nickel, platinum, gold or a composite metal laminate material, and the preparation method of the nickel, platinum, gold or composite metal material includes but is not limited to magnetron sputtering and electron beam evaporation; the patterning method is an etching or stripping process.

[0016] Compared with the prior art, the present invention has at least the following beneficial technical effects: 1) The overall design of the present invention is based on a Schottky junction to achieve self-powered characteristics, rather than a more common heterojunction. The preparation process of the Schottky junction usually only requires a lower processing temperature, which makes it highly compatible with flexible substrates. The use of the Schottky junction avoids the damage to the flexible substrate caused by high-temperature processing and simplifies the manufacturing process. In addition, the Schottky barrier structure does not need to rely on a complex carrier recombination process like a traditional PN junction to generate current. Its lower forward voltage and simplified band structure enable carriers to flow quickly and respond to light signals more efficiently. At the same time, the built-in electric field generated by the detector can effectively separate photogenerated electrons and holes at lower energy, thereby having self-powered characteristics. This structure not only improves the photoelectric conversion efficiency, but also gives the device the advantages of fast response, low dark current, high sensitivity and low noise.

[0017] The self-powered UV detector on a flexible substrate can adapt to more complex working environments. It does not require additional power supply and has stronger compatibility with equipment installation and usage conditions.

[0018] 2) The present invention improves the photoelectric detection performance of the device by asymmetric design of electrode materials and contact area. Due to the difference in materials, a significant potential barrier difference is formed between Schottky contact and ohmic contact, which enhances the built-in electric field strength and improves the separation efficiency of photogenerated carriers.

[0019] The device increases the volume of the first metal electrode and the ohmic contact area. The increased ohmic contact area helps to form better ohmic contact characteristics, reduce contact resistance, and further increase the potential barrier difference between the electrodes, thereby enhancing the total built-in electric field. The enhanced built-in electric field helps to accelerate the separation and transmission of photogenerated carriers, thereby improving the photocurrent output and response speed. In addition, since the contact resistance is reduced, the increase in the ohmic contact area helps to reduce the energy loss of the charge at the contact interface, allowing the charge extracted from the light absorption area to flow to the external circuit more efficiently, further improving the self-power supply capability, especially in weak light conditions. Signal output can also be achieved. Overall, increasing the ohmic contact area not only improves the photodetection performance, but also significantly enhances the self-power supply capability and response speed of the device.

[0020] 3) In the present invention, aluminum oxide is used as a passivation layer, and the coverage of the layer is positioned through precise graphic processing, so that the first metal electrode and the passivation layer do not contact each other except for a small amount of edge overlap. This graphic aluminum oxide passivation layer can improve the large number of dangling bonds and other surface defects on the surface of gallium oxide, thereby increasing the Schottky barrier height and enhancing the built-in electric field. This design allows the aluminum oxide passivation layer to play a positive role while avoiding adverse effects on the ohmic electrode function, thereby enhancing the electrical performance and long-term stability of the entire device. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a gallium oxide-based flexible self-powered solar-blind ultraviolet detector in Example 1; Figure 2 A three-dimensional schematic diagram of a gallium oxide-based flexible self-powered solar-blind ultraviolet detector in Example 1; Figure 3 A schematic top view of a gallium oxide-based flexible self-powered solar-blind ultraviolet detector in Example 1; Figure 4 Schematic diagram of the process flow of a gallium oxide-based flexible self-powered solar-blind ultraviolet detector in Example 1.

[0022] In the figure, 1 is substrate; 2 is gallium oxide film; 3 is the first metal electrode; 4 is the passivation layer; 5 is the second metal electrode. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0025] It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be another element centered thereon. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be another element centered thereon at the same time. The terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc. used herein indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0027] Reference Figure 1 A gallium oxide-based flexible self-powered day-blind ultraviolet detector comprises a substrate layer 1; a gallium oxide film 2 is prepared on the substrate layer 1; a first metal electrode 3 is prepared on the gallium oxide film 2; a passivation layer 4 is prepared on the gallium oxide film 2; the bottom surface of the first metal electrode 3 is complementary to the shape of the passivation layer 4, and the first metal electrode 3 and the passivation layer 4 are both in direct contact with the gallium oxide film 2; a second metal electrode 5 is prepared on the passivation layer 4; the second metal electrode 5 is in direct contact with the passivation layer 4; the second metal electrode 5 and the first metal electrode 3 form an interdigitated electrode structure. The first metal electrode 3 forms an ohmic contact with the gallium oxide film 2, and does not contact the passivation layer 4 except for the edge overlap area less than 1 μm; the second metal electrode 5 forms a Schottky contact with the gallium oxide film 2. The passivation layer 4 helps to improve the large number of dangling bonds or other surface defects on the surface of the gallium oxide film. At the same time, when the passivation layer 4 is 5 nm or less, the metal and the semiconductor can form a Schottky contact through the tunneling effect. The improvement of surface defects can indirectly increase the Schottky barrier.

[0028] The material of the substrate layer 1 is a flexible material such as polyimide (PI) or mica with a temperature resistance of more than 400° C., so as to adapt to the entire preparation process and withstand various mechanical bending conditions.

[0029] The gallium oxide film 2 is an amorphous or polycrystalline gallium oxide film, which is prepared by low-temperature coating methods such as magnetron sputtering and atomic layer deposition. If the film thickness is too small, it will not fully absorb light, and if the film thickness is too large, it will increase unnecessary film preparation time. Therefore, the film thickness is controlled between 200 nm and 600 nm.

[0030] The material of the passivation layer 4 is aluminum oxide, which is prepared by atomic layer deposition, and its thickness is controlled to be less than or equal to 5 nm. The reason is that the aluminum oxide film prepared by atomic layer deposition technology has stable physical and chemical properties, good surface quality, and can accurately control the thickness. The aluminum oxide film with a sufficiently small thickness can not only play a passivation role, but also avoid the absorption of light by the passivation layer and hinder the movement of carriers.

[0031] The first metal electrode 3 is made of titanium, aluminum, silver or a composite metal laminate material and is prepared by electron beam evaporation or magnetron sputtering.

[0032] The second metal electrode 5 is made of nickel, platinum, gold or a composite metal laminate material and is prepared by electron beam evaporation or magnetron sputtering.

[0033] Furthermore, the passivation layer 4 and the first metal electrode 3 are patterned by stripping or etching, so that the passivation layer 4 and the first metal electrode 3 are complementary in pattern and are in direct contact with the gallium oxide film 2 but not in contact with each other.

[0034] Furthermore, the second metal electrode 5 is patterned by stripping or etching, so that the second metal electrode 5 is in direct contact with the passivation layer 4 and forms an interdigital structure with the first metal electrode 3 .

[0035] Furthermore, the ratio of the contact area between the first metal electrode 3 and the gallium oxide film 2 to the contact area between the second metal electrode 5 and the passivation layer 4 is greater than or equal to 2. Increasing the ohmic contact area helps to form a better quality ohmic contact, reduces the contact resistance, and further increases the potential barrier difference between the electrodes, thereby strengthening the built-in electric field. The enhanced built-in electric field helps to accelerate the separation and transmission of photogenerated carriers, thereby improving the photocurrent output and response speed. In addition, by reducing the contact resistance and increasing the ohmic contact area, it helps to reduce the energy loss of the charge at the contact interface, so that the charge extracted from the light absorption area can flow to the external circuit more efficiently, further improving the self-powered capability, especially in weak light conditions. Signal output can also be achieved.

[0036] Furthermore, the temperature of all process steps must be less than or equal to 400°C.

[0037] Furthermore, the gallium oxide film 2 is a photosensitive layer, and the first metal electrode 3 and the second metal electrode 5 with different sizes and materials form ohmic contact and Schottky contact with the gallium oxide film 2 respectively, thereby generating a built-in electric field, which can effectively separate photogenerated carriers and ultimately achieve self-powered characteristics.

[0038] Furthermore, the passivation layer 4 can reduce the interface defects of the gallium oxide film, play an interface buffering role, reduce the recombination of photogenerated carriers, and improve the carrier transport efficiency, thereby effectively improving the photoelectric response of the gallium oxide layer; and the passivation layer 4 can protect the gallium oxide layer to avoid damage during subsequent preparation and use; finally, the presence of the passivation layer 4 can increase the Schottky barrier height, further enhance the built-in electric field, and effectively improve the carrier separation efficiency.

[0039] The gallium oxide-based flexible self-powered day-blind ultraviolet detector provided by the present invention has the following working principle: by rationally designing asymmetric electrodes and inserting a passivation layer, the functions of each part are optimized, and efficient photoelectric detection and self-powered characteristics are achieved. The flexible substrate provides mechanical stability of the device in a curved environment; the ohmic contact area formed by the first metal electrode and the gallium oxide film is large, and the electrode material uses a low work function metal material to directly contact the gallium oxide, and then an auxiliary annealing process is used to form a high-quality ohmic contact, ensuring the rapid collection and transmission of photogenerated electrons; the Schottky contact area formed by the second metal electrode and the gallium oxide film is small, and the electrode material uses a high work function metal material to form a Schottky contact with gallium oxide. On this basis, an extremely thin aluminum oxide passivation layer is inserted between the second metal electrode and the gallium oxide film, which effectively suppresses surface defects and pinning effects, and at the same time maintains a stable barrier height and Schottky contact through the tunneling effect, thereby enhancing the built-in electric field. The total built-in electric field of the device is jointly determined by the ohmic contact quality and the barrier height of the Schottky contact, and can efficiently separate photogenerated electron-hole pairs. Under ultraviolet light, the carrier separation and transfer process drives the external current, achieving efficient photodetection without external power supply. The device's structural design maximizes the response speed, stability and self-power capability while reducing dark current. refer to Figure 4 The present invention also provides a method for preparing a solar-blind ultraviolet detector, comprising the following steps: S1. Depositing a gallium oxide thin film 2 on a flexible substrate layer 1 made of PI or mica at room temperature.

[0040] The method of depositing the gallium oxide film 2 includes but is not limited to low-temperature coating methods such as magnetron sputtering and atomic layer deposition. The thickness of the deposited gallium oxide film 2 is 300-400 nm.

[0041] S2. A 5 nm thick aluminum oxide layer is prepared on the gallium oxide film 2 by atomic layer deposition at a deposition temperature of 200° C., and then the aluminum oxide layer is patterned by etching to obtain a passivation layer 4. The patterning method may also adopt a stripping process.

[0042] S3. Deposit Ti / Au metal on the gallium oxide film 2 by electron beam evaporation or magnetron sputtering, and pattern it by lift-off process. After patterning, the finger width of the first metal electrode is 10~30 um, and the finger length is 200~800 um. The first metal electrode adopts a composite metal laminate material, in which the thickness of the Ti layer is 20~40 nm, and the thickness of the Au layer is 60~200 nm. Then, it is annealed at 300~400℃ and the holding time is 30~120 minutes in an air atmosphere to obtain a first metal electrode 3 complementary to the pattern of the passivation layer 4; the pattern of the first metal electrode 3 is in direct contact with the passivation layer 4 and the gallium oxide film 2, and does not contact the passivation layer except for a small amount of edge overlap area; the first metal electrode 3 forms an ohmic contact with the gallium oxide film 2, and does not contact the passivation layer 4 except for the edge overlap area less than 1 um; The annealing treatment is conducive to forming a better ohmic contact while ensuring that the substrate is not affected, thereby forming a stronger built-in electric field, and further facilitating the realization of self-powered characteristics.

[0043] The annealing method is tubular furnace annealing; the gas atmosphere of the annealing process includes but is not limited to nitrogen, argon, and air; the temperature of the annealing process is 300-400°C; the holding time of the annealing process is controlled at 30-120 minutes; S4, depositing Ni / Au metal on the passivation layer 4 by electron beam evaporation or magnetron sputtering, and patterning by lift-off process, the second metal electrode after patterning has a finger width of 5-15 um and a finger length of 200-800 um. The second metal electrode adopts a composite metal laminate material, wherein the thickness of the Ni layer is 20-40 nm, and the thickness of the Au layer is 60-200 nm, to obtain a second metal electrode 5 in a forked finger shape with the first metal electrode 3.

[0044] Furthermore, in step S3 and step S4, the patterning method for Ti / Au and Ni / Au metals includes etching or stripping process.

[0045] The following are specific embodiments. It should be noted that these embodiments are preferred examples of the present invention and are used for those skilled in the art to understand the present invention, but the present invention is not limited to these embodiments.

[0046] Example 1 Reference Figure 1-3, a gallium oxide-based flexible self-powered day-blind ultraviolet detector, comprising a substrate layer 1; the material of the substrate layer is PI; a gallium oxide film 2 with a thickness of 600 nm is prepared on the substrate layer 1; a first metal electrode 3 is prepared on the gallium oxide film 2; a passivation layer 4 is prepared on the gallium oxide film 2; the passivation layer material is aluminum oxide and has a thickness of 5 nm; the first metal electrode 3 and the passivation layer 4 are complementary in shape and are in direct contact with the gallium oxide film 2, while the first metal electrode 3 and the passivation layer 4 do not contact each other; a second metal electrode 5 is prepared on the passivation layer 4; the second metal electrode 5 is in direct contact with the passivation layer 4; the second metal electrode 5 and the first metal electrode 3 form an interdigital electrode structure. The first metal electrode 3 forms an ohmic contact with the gallium oxide film 2, and does not contact the passivation layer 4 except for the edge overlap area less than 1 um; the second metal electrode 5 forms a Schottky contact with the gallium oxide film 2. The ratio of the contact area between the first metal electrode 3 and the gallium oxide film 2 to the contact area between the second metal electrode 5 and the passivation layer 4 is 3. The material of the first metal electrode 3 is a Ti / Au composite metal laminate material, wherein the thickness of the Ti layer is 20 nm and the thickness of the Au layer is 140 nm. The material of the second metal electrode 5 is a Ni / Au composite metal laminate material, wherein the thickness of the Ni layer is 20 nm and the thickness of the Au layer is 140 nm. The passivation layer 4 is an aluminum oxide film with a thickness of 5 nm, which can optimize the surface quality and stability of the semiconductor.

[0047] The interdigital width of the first metal electrode 3 is 15 um, and the interdigital length is 800 um; the interdigital width of the second metal electrode 5 is 5 um, and the interdigital length is 800 um; the number of interdigital pairs is 20 pairs, and the interdigital gap is 20 um; the electrode is placed in the center of the substrate.

[0048] Due to the different materials and sizes of the electrodes on both sides and the effect of the passivation layer 4, different contacts are formed between the electrodes on both sides and the gallium oxide film 2, thereby forming a built-in electric field. When irradiated with light in the target band, the gallium oxide film 2 generates a large number of photogenerated carriers, which are quickly separated by the built-in electric field and captured by the metal electrodes on both sides, thereby realizing the self-powered characteristic.

[0049] Example 2 Reference Figure 1-3The difference between this embodiment and embodiment 1 is that the thickness of the gallium oxide film 2 is 400 nm, the thickness of the passivation layer 4 is 3 nm, the interdigital width of the first metal electrode 3 is 25 um, and the interdigital length is 600 um; the interdigital width of the second metal electrode 5 is 10 um, and the interdigital length is 600 um. The ratio of the contact area between the first metal electrode 3 and the gallium oxide film 2 to the contact area between the second metal electrode 5 and the passivation layer 4 is 2.5. The material of the first metal electrode 3 is Al, and the thickness of the Al layer is 30 nm. The material of the second metal electrode 5 is Pt, and the thickness of the Pt layer is 30 nm.

[0050] Example 3 Reference Figure 1-3 The difference between this embodiment and embodiment 1 is that the thickness of the gallium oxide film 2 is 200 nm, the thickness of the passivation layer 4 is 1 nm, the interdigital width of the first metal electrode 3 is 30 um, and the interdigital length is 400 um; the interdigital width of the second metal electrode 5 is 15 um, and the interdigital length is 400 um. The ratio of the contact area between the first metal electrode 3 and the gallium oxide film 2 to the contact area between the second metal electrode 5 and the passivation layer 4 is 2. The material of the first metal electrode 3 is Ti, and the thickness of the Ti layer is 40 nm. The material of the second metal electrode 5 is Ni, and the thickness of the Ni layer is 40 nm.

[0051] Example 4 Reference Figure 1-3 The difference between this embodiment and embodiment 1 is that the material of the substrate layer is mica, the thickness of the gallium oxide film 2 is 400 nm; the width of the interdigital fingers of the first metal electrode 3 is 30 um, and the length of the interdigital fingers is 200 um; the width of the interdigital fingers of the second metal electrode 5 is 5 um, and the length is 200 um. The ratio of the contact area between the first metal electrode 3 and the gallium oxide film 2 to the contact area between the second metal electrode 5 and the passivation layer 4 is 6. The material of the first metal electrode 3 is Ag, and the thickness of the Ag layer is 20 nm. The material of the second metal electrode 5 is Au, and the thickness of the Au layer is 20 nm.

[0052] Example 5 refer to Figure 4 This embodiment provides a method for preparing the solar-blind ultraviolet detector of embodiment 1, comprising the following steps: S1. Depositing a gallium oxide thin film 2 with a thickness of 600 nm on a flexible substrate layer 1 made of PI at room temperature by magnetron sputtering.

[0053] S2. A 5 nm thick aluminum oxide layer is prepared on the gallium oxide film 2 by atomic layer deposition at a deposition temperature of 200° C., and then the aluminum oxide layer is patterned by a stripping method to obtain a passivation layer 4.

[0054] S3. Deposit Ti / Au metal on the gallium oxide film 2 by electron beam evaporation, and pattern it by lift-off process. After patterning, the width of the first metal electrode fork finger is 15 um, and the length of the fork finger is 800 um. The thickness of the Ti layer is 20 nm, and the thickness of the Au layer is 140 nm. Then, annealing treatment is carried out in a tube furnace at 300°C and the holding time is 30 minutes in an air atmosphere to obtain a first metal electrode 3 complementary to the pattern of the passivation layer 4; the pattern of the first metal electrode 3 is in direct contact with the passivation layer 4 and the gallium oxide film 2, and does not contact the passivation layer 4; the first metal electrode 3 forms an ohmic contact with the gallium oxide film 2, and does not contact the passivation layer 4 except for the edge overlap area less than 1 μm; The annealing treatment is conducive to forming a better ohmic contact while ensuring that the substrate is not affected, thereby forming a stronger built-in electric field, and further facilitating the realization of self-powered characteristics.

[0055] S4, depositing Ni / Au metal on the passivation layer 4 by electron beam evaporation, and patterning by lift-off process, the patterned second metal electrode has a finger width of 5 um and a finger length of 800 um. The thickness of the Ni layer is 20 nm, and the thickness of the Au layer is 140 nm, so as to obtain the second metal electrode 5 forming a finger shape with the first metal electrode 3.

[0056] Example 6 refer to Figure 4 This embodiment provides a method for preparing the solar-blind ultraviolet detector of embodiment 2, which is different from embodiment 5 in that: S1. The thickness of the gallium oxide film 2 is 400 nm.

[0057] S2. The thickness of the aluminum oxide passivation layer 4 is 3 nm.

[0058] S3, depositing Al metal on the gallium oxide film 2, and after patterning, the first metal electrode has a finger width of 25 um and a finger length of 600 um. The thickness of the Al layer is 30 nm, and then annealing is performed in a tube furnace at 350° C. for 60 minutes in a nitrogen atmosphere to obtain a first metal electrode 3 complementary to the pattern of the passivation layer 4.

[0059] S4, depositing Pt metal on the passivation layer 4, after patterning, the width of the second metal electrode fork finger is 10 um, the length of the fork finger is 600 um. The thickness of the Pt layer is 30 nm, and the second metal electrode 5 forming a fork finger shape with the first metal electrode 3 is obtained.

[0060] Example 7 refer to Figure 4 This embodiment provides a method for preparing the solar-blind ultraviolet detector of embodiment 3, which is different from embodiment 5 in that: S1. Deposit a 200 nm thick gallium oxide film 2 at 300° C. using an atomic layer deposition method.

[0061] S2. The thickness of the aluminum oxide passivation layer 4 is 1 nm, and the aluminum oxide layer is patterned by etching.

[0062] S3, deposit Ti metal on the gallium oxide film 2 by magnetron sputtering, and pattern it by etching process. After patterning, the width of the first metal electrode fork is 30 um, and the length of the fork is 400 um. The thickness of the Ti layer is 40 nm, and then annealing treatment is performed at 400°C in an argon atmosphere for 75 minutes to obtain a first metal electrode 3 complementary to the pattern of the passivation layer 4.

[0063] S4, depositing Ni metal on the passivation layer 4 by magnetron sputtering, and patterning by etching process, the patterned second metal electrode has a finger width of 15 um and a finger length of 400 um. The thickness of the Ni layer is 40 nm, and the second metal electrode 5 forming a finger shape with the first metal electrode 3 is obtained.

[0064] Example 8 refer to Figure 4 This embodiment provides a method for preparing the solar-blind ultraviolet detector of embodiment 4, which is different from embodiment 5 in that: S1. Depositing a gallium oxide thin film 2 with a thickness of 400 nm on a flexible substrate layer 1 made of mica at 300° C. by using an atomic layer deposition method.

[0065] S2. Patterning the aluminum oxide layer using an etching method.

[0066] S3, Ag metal is deposited on the gallium oxide film 2 by magnetron sputtering, and patterned by etching process. After patterning, the width of the first metal electrode fork is 30 um and the length is 200 um. The thickness of the Ag layer is 20 nm, and then annealing treatment is performed at 400°C for 120 minutes in a nitrogen atmosphere to obtain a first metal electrode 3 complementary to the pattern of the passivation layer 4.

[0067] S4, depositing Au metal on the passivation layer 4 by magnetron sputtering, and patterning by etching process, the patterned second metal electrode has a finger width of 5 um and a finger length of 200 um. The Au layer thickness is 20 nm, and the second metal electrode 5 forming a finger shape with the first metal electrode 3 is obtained.

[0068] The term "consisting of" describing a combination shall include the identified elements, ingredients, parts or steps and other elements, ingredients, parts or steps that do not substantially affect the basic novel characteristics of the combination. The use of the terms "comprising" or "including" to describe a combination of elements, ingredients, parts or steps herein also contemplates embodiments that consist essentially of these elements, ingredients, parts or steps. By using the term "may", it is intended to illustrate that any of the attributes described that "may" be included are optional.

[0069] Multiple elements, ingredients, parts or steps can be provided by a single integrated element, ingredient, part or step. Alternatively, a single integrated element, ingredient, part or step can be divided into separate multiple elements, ingredients, parts or steps. The disclosure "one" or "an" used to describe an element, ingredient, part or step is not intended to exclude other elements, ingredients, parts or steps.

[0070] It should be understood that the above description is for illustration and not for limitation. Many embodiments and many applications beyond the examples provided will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of the present teachings should not be determined with reference to the above description, but rather with reference to the foregoing claims and the full scope of equivalents to which such claims are entitled. For the purpose of comprehensiveness, all articles and references, including disclosures of patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended to be a waiver of such subject matter, nor should it be considered that the applicant has not considered such subject matter to be part of the disclosed inventive subject matter.

Claims

1. A gallium oxide-based flexible self-powered solar-blind ultraviolet detector, characterized in that: The invention comprises a substrate layer (1), a gallium oxide film (2) being prepared on the substrate layer (1); a first metal electrode (3) being prepared on the gallium oxide film (2); a passivation layer (4) being prepared on the gallium oxide film (2); a contact surface between the first metal electrode (3) and the gallium oxide film (2) being complementary in shape to the passivation layer (4); the first metal electrode (3) and the passivation layer (4) both being in direct contact with the gallium oxide film (2); a second metal electrode (5) being prepared on the passivation layer (4); and the second metal electrode (5) and the first metal electrode (3) forming an interdigitated electrode structure.

2. The gallium oxide-based flexible self-powered solar-blind ultraviolet detector according to claim 1, characterized in that: An ohmic contact is formed between the first metal electrode (3) and the gallium oxide film (2); and a Schottky contact is formed between the second metal electrode (5) and the gallium oxide film (2).

3. The gallium oxide-based flexible self-powered solar-blind ultraviolet detector according to claim 1, characterized in that: The ratio of the contact area between the first metal electrode (3) and the gallium oxide film (2) to the contact area between the second metal electrode (5) and the gallium oxide film (2) is greater than or equal to 2.

4. The gallium oxide-based flexible self-powered solar-blind ultraviolet detector according to claim 1, characterized in that: The substrate layer (1) is made of a flexible material capable of withstanding a high temperature of 400 degrees Celsius.

5. The gallium oxide-based flexible self-powered solar-blind ultraviolet detector according to claim 1, characterized in that: The passivation layer (4) is an aluminum oxide film with a thickness less than or equal to 5 nm.

6. A method for preparing a gallium oxide-based flexible self-powered solar-blind ultraviolet detector, characterized in that: The following steps are involved: S1, depositing a gallium oxide thin film (2) on a substrate layer (1); S2, depositing aluminum oxide on the gallium oxide film (2), and then patterning the aluminum oxide layer to obtain a passivation layer (4); S3, depositing metal on the gallium oxide film (2), patterning it, and then performing annealing to form an ohmic contact to obtain a first metal electrode (3); the first metal electrode (3) forms an ohmic contact with the gallium oxide film (2), and does not contact the passivation layer except for the edge overlap area; S4, depositing metal on the passivation layer (4) and patterning the metal to obtain a second metal electrode (5) in an interdigitated shape with the first metal electrode (3); the second metal electrode (5) forms a Schottky contact with the gallium oxide film (2).

7. The gallium oxide-based flexible self-powered solar-blind ultraviolet detector according to claim 6, characterized in that: In the step S1, the method of depositing the gallium oxide film (2) includes but is not limited to magnetron sputtering and atomic layer deposition; the thickness of the gallium oxide film (2) is between 200 nm and 600 nm.

8. The gallium oxide-based flexible self-powered solar-blind ultraviolet detector according to claim 6, characterized in that: In the step S2, the material of the passivation layer (4) is aluminum oxide, the method of depositing the aluminum oxide layer is atomic layer deposition, and the patterning method is etching or stripping process.

9. The gallium oxide-based flexible self-powered solar-blind ultraviolet detector according to claim 6, characterized in that: In the step S3, the deposited metal is titanium, aluminum, silver or a composite metal laminate material, and the preparation method of the titanium, aluminum, silver or composite metal laminate material includes but is not limited to magnetron sputtering and electron beam evaporation; the patterning method is an etching or stripping process; the annealing temperature is 300-400° C.; the annealing time is 30-120 minutes; the first metal electrode (3) is in direct contact with the gallium oxide film (2), and does not contact the passivation layer (4) except for the edge overlap area.

10. The gallium oxide-based flexible self-powered solar-blind ultraviolet detector according to claim 6, characterized in that: In step S4, the deposited metal is nickel, platinum, gold or a composite metal laminate material, and the preparation method of the nickel, platinum, gold or composite metal material includes but is not limited to magnetron sputtering and electron beam evaporation; the patterning method is an etching or stripping process.

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