Solar-blind ultraviolet photodetector and its preparation method and application

Abstract

The present invention relates to the field of ultraviolet detectors, and in particular, provides a solar-blind ultraviolet photodetector and a preparation method and application thereof. The preparation method comprises the following steps: S1, first spin-coating a gallium oxide precursor solution on a substrate, and obtaining a gallium oxide polycrystalline film after a first heat treatment; S2, depositing a metal electrode on the surface of the gallium oxide polycrystalline film; S3, second spin-coating an indium gallium zinc oxide precursor solution on the metal electrode, and obtaining a solar-blind ultraviolet photodetector after a second heat treatment. The process of the present invention is reliable and has good repeatability, and the obtained solar-blind ultraviolet photodetector has at least the advantages of high responsiveness, high detection rate, and relatively high light-dark current.

Description

Technical Field

[0001] The present invention relates to the field of ultraviolet detectors, and in particular to a solar-blind ultraviolet photoelectric detector and a preparation method and application thereof. Background Art

[0002] Due to the strong absorption of 200~280 nm ultraviolet light by the ozone layer in the atmosphere, photodetectors working in this "solar blind zone" band exhibit low background noise characteristics. Solar blind ultraviolet photodetectors have broad application prospects in military and civilian fields such as flame monitoring, missile warning, and space communications. In recent years, with the increasing requirements for solar blind detection, ultraviolet photodetection technology based on wide bandgap semiconductor materials such as diamond, gallium oxide (Ga2O3), aluminum gallium nitride (AlGaN), and zinc magnesium oxide (ZnMgO) has become one of the research hotspots. Among them, Ga2O3 is an emerging ultra-wide bandgap semiconductor material. Because of its intrinsic solar blindness, high visible light transparency, and excellent physical and chemical properties, it is considered to be one of the ideal materials for developing solar blind ultraviolet photodetectors. At present, single crystal and polycrystalline structure photoelectric devices based on Ga2O3 have been reported. Existing results show that current solar blind detectors still have problems such as low responsivity, low detection rate, and low light-to-dark current ratio. Its performance depends greatly on the quality of the film and the structural design of the device.

[0003] In view of this, the present invention is proposed. Summary of the invention

[0004] The purpose of the present invention is to provide a solar-blind ultraviolet photodetector and a preparation method and application thereof, so as to solve the problems of low responsiveness, low detection rate and low light-to-dark current ratio of the solar-blind detector in the prior art.

[0005] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0006] In a first aspect, the present invention provides a method for preparing a solar-blind ultraviolet photodetector, comprising the following steps:

[0007] S1. Spin-coating a gallium oxide precursor solution on a substrate for the first time, and obtaining a gallium oxide polycrystalline thin film after a first heat treatment; wherein the first spin coating includes pre-spin coating at a rotation speed of 900-1100 r / min for 8-12 s, and then spin coating again at a rotation speed of 2800-3200 r / min for 25-35 s; the first heat treatment includes first keeping the temperature at 180-220° C. for 8-12 min, then heating to 450-550° C. for 10-20 min, and finally annealing at 600-700° C. for 1.5-2.5 h;

[0008] S2, depositing a metal electrode on the surface of the gallium oxide polycrystalline thin film;

[0009] S3. Spin-coating an indium gallium zinc oxide precursor solution on the metal electrode for the second time, and obtaining a day-blind ultraviolet photodetector after a second heat treatment; wherein the second spin coating includes pre-spin coating at a rotation speed of 900-1100 r / min for 8-12 s, and then spin coating again at a rotation speed of 2800-3200 r / min for 25-35 s; the second heat treatment includes first keeping warm at 140-160°C for 8-12 min, then annealing at 280-320°C for 20-40 min, and finally post-annealing at 280-320°C for 1.5-2.5 h.

[0010] As a further preferred technical solution, the gallium oxide precursor solution is prepared in the following manner:

[0011] Gallium nitrate is added to dimethoxyethanol, shaken and mixed for 5-10 minutes, then heated to 60-80°C, and treated at a stirring speed of 1800-2200 r / min for 1.5-2.5 hours, and finally left at room temperature for 22-26 hours to obtain a gallium oxide precursor solution.

[0012] As a further preferred technical solution, the metal ion concentration in the gallium oxide precursor solution is 0.3-0.8 mol / L.

[0013] As a further preferred technical solution, the gallium oxide precursor solution dripped onto the substrate is 45-55 μL.

[0014] As a further preferred technical solution, the indium gallium zinc oxide precursor solution is prepared in the following manner:

[0015] Gallium nitrate, zinc nitrate and indium nitrate are added to dimethoxyethanol in a metal ion molar ratio of 1:1:1, and the mixture is shaken and mixed for 5-10 minutes, then heated to 60-80°C, and treated at a stirring speed of 1800-2200 r / min for 1.5-2.5 hours, and finally filtered through an organic filter medium with a pore size of less than 0.22 µm to obtain an indium gallium zinc oxide precursor solution.

[0016] As a further preferred technical solution, in the indium gallium zinc oxide precursor solution, the total concentration of metal ions is 1.3-1.8 mol / L.

[0017] As a further preferred technical solution, the indium gallium zinc oxide precursor solution dripped onto the metal electrode is 95-105 μL.

[0018] As a further preferred technical solution, depositing a metal electrode on the surface of the gallium oxide polycrystalline thin film comprises:

[0019] A mask is covered on the surface of the gallium oxide polycrystalline film, and then a metal electrode is deposited by sputtering deposition.

[0020] In a second aspect, the present invention provides a solar-blind ultraviolet photoelectric detector manufactured by the above-mentioned method for preparing the solar-blind ultraviolet photoelectric detector.

[0021] In a third aspect, the present invention provides an application of the above-mentioned solar-blind ultraviolet photoelectric detector in flame monitoring, missile early warning or space communication.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] The preparation method of the solar-blind ultraviolet photodetector provided by the present invention adopts a specific first spin coating and a first heat treatment method to obtain a gallium oxide polycrystalline film on a substrate, then deposits a metal electrode, and finally adopts a specific second spin coating and a second heat treatment method to obtain a solar-blind ultraviolet photodetector. The method has reliable process and good repeatability. Heat treatment after spin coating can optimize the quality of the film. The obtained solar-blind ultraviolet photodetector can not only realize ultraviolet band light absorption, but also enhance the photoelectric conversion performance, detect a larger photocurrent, and has a higher responsiveness, a higher detection rate, a higher light-dark current ratio, and an excellent overall photoelectric performance.

[0024] Furthermore, the raw materials used in the preparation of the gallium oxide precursor solution and the indium gallium zinc oxide precursor solution of the present invention are gallium nitrate, zinc nitrate, indium nitrate and the like, which have a wide range of sources and low costs, and are therefore conducive to promoting the widespread application of solar-blind ultraviolet photodetectors. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a surface morphology of the gallium oxide layer in the day-blind ultraviolet photodetector of Example 20;

[0026] Figure 2 This is a surface morphology of indium gallium zinc oxide in the day-blind ultraviolet photodetector of Example 20;

[0027] Figure 3 This is a cross-sectional morphology diagram of the day-blind ultraviolet photodetector of Example 20;

[0028] Figure 4 XRD diagram of IGZO / Ga2O3 and Ga2O3 thin films in the day-blind ultraviolet photodetector of Example 20;

[0029] Figure 5 This is the XRD pattern of the IGZO film and the sapphire substrate in the day-blind ultraviolet photodetector of Example 20;

[0030] Figure 6 The absorption spectra of IGZO, Ga2O3 and IGZO / Ga2O3 in the day-blind ultraviolet photodetector of Example 20;

[0031] Figure 7 The IV characteristics of the day-blind ultraviolet photodetector under ultraviolet illumination conditions in Example 20;

[0032] Figure 8 The response R and normalized detection rate D of the day-blind ultraviolet photodetector of Example 20 vary with voltage under 254 nm illumination conditions. DETAILED DESCRIPTION

[0033] The embodiments of the present invention will be described in detail below in conjunction with examples, but those skilled in the art will appreciate that the following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention. If no specific conditions are specified in the examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer.

[0034] As one aspect of the present invention, the present invention provides a method for preparing a solar-blind ultraviolet photoelectric detector, comprising the following steps:

[0035] S1. Spin-coating a gallium oxide precursor solution on a substrate for the first time, and obtaining a gallium oxide polycrystalline thin film after a first heat treatment; wherein the first spin coating includes pre-spin coating at a rotation speed of 900-1100 r / min for 8-12 s, and then spin coating again at a rotation speed of 2800-3200 r / min for 25-35 s; the first heat treatment includes first keeping the temperature at 180-220° C. for 8-12 min, then heating to 450-550° C. for 10-20 min, and finally annealing at 600-700° C. for 1.5-2.5 h;

[0036] S2, depositing a metal electrode on the surface of the gallium oxide polycrystalline thin film;

[0037] S3. Spin-coating an indium gallium zinc oxide precursor solution on the metal electrode for the second time, and obtaining a day-blind ultraviolet photodetector after a second heat treatment; wherein the second spin coating includes pre-spin coating at a rotation speed of 900-1100 r / min for 8-12 s, and then spin coating again at a rotation speed of 2800-3200 r / min for 25-35 s; the second heat treatment includes first keeping warm at 140-160°C for 8-12 min, then annealing at 280-320°C for 20-40 min, and finally annealing at 600-700°C for 1.5-2.5 h.

[0038] Typically, but not limiting, the rotation speed of the pre-spin coating in the first spin coating and the second spin coating independently includes 900r / min, 910r / min, 920r / min, 930r / min, 940r / min, 950r / min, 960r / min, 970r / min, 980r / min, 990r / min, 1000r / min, 1010r / min, 1020r / min, 1030r / min, 1040r / min, 1050r / min, 1060r / min, 1070r / min, 1080r / min, 1090r / min or 1100r / min. The time of pre-spin coating independently includes 8s, 9s, 10s, 11s or 12s. The rotation speeds for the second spin coating each independently include 2800r / min, 2810r / min, 2820r / min, 2830r / min, 2840r / min, 2850r / min, 2860r / min, 2870r / min, 2880r / min, 2890r / min, 2900r / min, 2950r / min, 3000r / min, 3050r / min, 3100r / min, 3150r / min or 3200r / min. The first insulation temperature in the first heat treatment includes but is not limited to 180℃, 185℃, 190℃, 195℃, 200℃, 205℃, 210℃, 215℃ or 220℃, the first insulation time includes but is not limited to 8min, 9min, 10min, 11min or 12min, the insulation temperature after heating includes but is not limited to 450℃, 460℃, 470℃, 480℃, 490℃, 500℃, 510℃, 520℃, 530℃, 540℃ or 550℃, the insulation time after heating includes but is not limited to 10min, 11min, 12min, 13min, 14min, 15min, 16min, 17min, 18min, 19min or 20min. The annealing temperature includes but is not limited to 600°C, 610°C, 620°C, 630°C, 640°C, 650°C, 660°C, 670°C, 680°C, 690°C or 700°C, and the annealing time includes but is not limited to 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2h, 2.1h, 2.2h, 2.3h, 2.4h or 2.5h.The first insulation temperature in the second heat treatment includes but is not limited to 140°C, 142°C, 144°C, 146°C, 148°C, 150°C, 152°C, 154°C, 156°C, 158°C or 160°C, the first insulation time includes but is not limited to 8min, 9min, 10min, 11min or 12min, the first annealing temperature includes but is not limited to 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 315°C or 320°C, the first annealing time includes but is not limited to 2 The temperature of the final annealing includes but is not limited to 280°C, 285°C, 290°C, 295°C, 300°C, 305°C, 315°C or 320°C, and the time of the final annealing includes but is not limited to 1.5h, 1.6h, 1.7h, 1.8h, 1.9h, 2h, 2.1h, 2.2h, 2.3h, 2.4h or 2.5h.

[0039] The main function of the pre-spin coating in the present invention is to completely cover the corresponding precursor solution in the desired substrate or the channel between the metal electrodes, which is conducive to forming a more uniform, flat and denser film.

[0040] During the second heat treatment, the film is first kept at 140-160°C for 8-12 minutes to evaporate the liquid solvent, and then annealed at 280-320°C for 20-40 minutes to complete the conversion of indium gallium zinc oxide (IGZO), further evaporate the solvent in the solution, and form a relatively stable film. Finally, post-annealing at 280-320°C for 1.5-2.5 hours can promote crystal formation and form a denser film.

[0041] The preparation method of the solar-blind ultraviolet photodetector adopts a specific first spin coating and a first heat treatment method to obtain a gallium oxide polycrystalline film on a substrate, and then deposits a metal electrode, and finally adopts a specific second spin coating and a second heat treatment method to obtain a solar-blind ultraviolet photodetector. The method has a reliable process and good repeatability. Heat treatment after spin coating can optimize the quality of the film. The obtained solar-blind ultraviolet photodetector can not only realize ultraviolet band light absorption, but also enhance the photoelectric conversion performance, detect a larger photocurrent, and has a higher responsiveness, a higher detection rate, a higher light-dark current ratio, and an excellent overall photoelectric performance.

[0042] Optionally, the temperature may be maintained on a hot stage, and the heating rate when the temperature is increased from 180-220° C. to 450-550° C. may be 10° C. / min. Annealing may be performed in a box furnace.

[0043] In an optional embodiment, the gallium oxide precursor solution is prepared in the following manner:

[0044] Gallium nitrate is added to dimethoxyethanol, shaken and mixed for 5-10 minutes, then heated to 60-80°C, and treated at a stirring speed of 1800-2200 r / min for 1.5-2.5 hours, and finally left at room temperature for 22-26 hours to obtain a gallium oxide precursor solution.

[0045] The oscillating mixing may be performed by a vortex mixer, and the stirring may be performed by a heated magnetic stirrer. The temperature of the room temperature is 20-28° C., such as 25° C. The gallium nitrate may be a gallium nitrate hydrate.

[0046] The time of the above-mentioned oscillation mixing includes but is not limited to 5 min, 6 min, 7 min, 8 min, 9 min or 10 min. The heating temperature includes but is not limited to 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C. The stirring speed includes but is not limited to 1800r / min, 1820r / min, 1840r / min, 1860r / min, 1880r / min, 1900r / min, 1920r / min, 1940r / min, 1960r / min, 1980r / min, 2000r / min, 2020r / min, 2040r / min, 2060r / min, 2080r / min, 2100r / min, 2120r / min, 2140r / min, 2160r / min, 2180r / min or 2200r / min. The stirring time includes, but is not limited to, 1.5 h, 1.6 h, 1.8 h, 2 h, 2.2 h or 2.5 h. The time for standing at room temperature includes, but is not limited to, 22 h, 23 h, 24 h, 25 h or 26 h.

[0047] In this embodiment, gallium nitrate is used as a raw material when preparing a gallium oxide precursor solution. The raw material is widely available and inexpensive. During the preparation process, oscillation mixing, heating stirring and room temperature storage are used to ensure the full dissolution of the raw material and further aging of the solution. The resulting precursor solution exhibits sol characteristics.

[0048] Optionally, before adding gallium nitrate to dimethoxyethanol, the method further comprises filtering dimethoxyethanol using a 0.22 μm organic filter head to remove impurities in the solvent.

[0049] In an optional embodiment, the metal ion concentration in the gallium oxide precursor solution is 0.3-0.8 mol / L. The above concentrations include but are not limited to 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L or 0.8 mol / L. It is understandable that the above metal ions are gallium ions. By controlling the metal ion concentration and the amount of addition in the gallium oxide and indium gallium zinc oxide precursor solutions, the uniformity and stability of the film can be ensured, thereby improving the quality of the heterojunction interface, reducing the defect density, and enhancing the performance of the device. Accurate precursor solution ratio helps to optimize the band gap structure of the material, making its detection performance in the ultraviolet band more prominent, and increasing the absorption and detection efficiency of ultraviolet light.

[0050] In an optional embodiment, the gallium oxide precursor solution added to the substrate is 45-55 μL. The volume of the above solution includes but is not limited to 45 μL, 46 μL, 47 μL, 48 μL, 49 μL, 50 μL, 51 μL, 52 μL, 53 μL, 54 μL or 55 μL. Reasonable metal ion concentration and drop amount help to adjust the electrical properties of the film, such as carrier concentration, mobility, etc., and improve the response speed, sensitivity and signal transmission capability of the ultraviolet detector.

[0051] In an optional embodiment, the indium gallium zinc oxide precursor solution is prepared in the following manner:

[0052] Gallium nitrate, zinc nitrate and indium nitrate are added to dimethoxyethanol in a metal ion molar ratio of 1:1:1, and the mixture is shaken and mixed for 5-10 minutes, then heated to 60-80°C, and treated at a stirring speed of 1800-2200 r / min for 1.5-2.5 hours, and finally filtered through an organic filter medium with a pore size of less than 0.22 µm to obtain an indium gallium zinc oxide precursor solution.

[0053] The gallium nitrate may be a gallium nitrate hydrate, the zinc nitrate may be a zinc nitrate hydrate, and the indium nitrate may be an indium nitrate hydrate.

[0054] The time of the above-mentioned oscillation mixing includes but is not limited to 5 min, 6 min, 7 min, 8 min, 9 min or 10 min. The heating temperature includes but is not limited to 60°C, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C or 80°C. The stirring speed includes but is not limited to 1800r / min, 1820r / min, 1840r / min, 1860r / min, 1880r / min, 1900r / min, 1920r / min, 1940r / min, 1960r / min, 1980r / min, 2000r / min, 2020r / min, 2040r / min, 2060r / min, 2080r / min, 2100r / min, 2120r / min, 2140r / min, 2160r / min, 2180r / min or 2200r / min. The stirring time includes but is not limited to 1.5 h, 1.6 h, 1.8 h, 2 h, 2.2 h or 2.5 h. The indium gallium zinc oxide precursor solution is ready for use.

[0055] In the present embodiment, gallium nitrate, indium nitrate and zinc nitrate are used as raw materials when preparing the indium gallium zinc oxide precursor solution. The raw materials are widely available and inexpensive. Oscillating mixing and heating stirring are used in the preparation process to ensure the full dissolution of the raw materials. The resulting precursor solution is ready for use.

[0056] In an optional embodiment, the total concentration of metal ions in the indium gallium zinc oxide precursor solution is 1.3-1.8 mol / L. The total concentration of metal ions refers to the total concentration of indium ions, gallium ions and zinc ions, and the total concentration includes but is not limited to 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, 1.6 mol / L, 1.7 mol / L or 1.8 mol / L.

[0057] In an optional embodiment, the indium gallium zinc oxide precursor solution dripped onto the metal electrode is 95-105 μL. The volume of the indium gallium zinc oxide precursor solution includes but is not limited to 95 μL, 96 μL, 97 μL, 98 μL, 99 μL, 100 μL, 101 μL, 102 μL, 103 μL, 104 μL or 105 μL.

[0058] In an optional implementation, depositing a metal electrode on the surface of the gallium oxide polycrystalline thin film includes:

[0059] A mask is covered on the surface of the gallium oxide polycrystalline film, and then a metal electrode is deposited by sputtering deposition.

[0060] The present invention does not limit the specific sputtering deposition method, and any method that can be implemented in the art can be used. The metal electrode includes but is not limited to a gold electrode.

[0061] Optionally, the substrate in the present invention includes but is not limited to a sapphire substrate.

[0062] As another aspect of the present invention, the present invention provides a solar-blind ultraviolet photodetector prepared by the preparation method of the solar-blind ultraviolet photodetector. The solar-blind ultraviolet photodetector prepared by the preparation method can not only realize ultraviolet band light absorption, but also enhance the photoelectric conversion performance, detect a larger photocurrent, and has a higher responsiveness, a higher detection rate, a higher light-dark current ratio, and an excellent overall photoelectric performance.

[0063] As another aspect of the present invention, the present invention provides an application of the above-mentioned day-blind ultraviolet photoelectric detector in flame monitoring, missile warning or space communication. The above-mentioned day-blind ultraviolet photoelectric detector is applied to flame monitoring, missile warning or space communication, which has the corresponding advantages of the above-mentioned day-blind ultraviolet photoelectric detector.

[0064] It should be noted that the present invention focuses on applying the above-mentioned day-blind ultraviolet photoelectric detector to flame monitoring, missile warning or space communication. The present invention does not specifically limit its specific application method, and any one that can be implemented in the field can be used.

[0065] The present invention is further described in detail below with reference to Examples and Comparative Examples.

[0066] Example 1

[0067] A method for preparing a solar-blind ultraviolet photoelectric detector comprises the following steps:

[0068] S1, first spin coating a gallium oxide precursor solution on a substrate, and obtaining a gallium oxide polycrystalline thin film after a first heat treatment; wherein the first spin coating includes pre-spin coating at a speed of 900 r / min for 12 seconds, and then spin coating again at a speed of 2800 r / min for 35 seconds; the first heat treatment includes first keeping the temperature at 180°C for 12 minutes, then heating to 450°C for 20 minutes, and finally annealing at 600°C for 2.5 hours;

[0069] S2, depositing a metal electrode on the surface of the gallium oxide polycrystalline thin film;

[0070] S3. Spin-coating an indium gallium zinc oxide precursor solution on the metal electrode for the second time, and obtaining a day-blind ultraviolet photodetector after a second heat treatment; wherein the second spin coating includes pre-spin coating at a rotation speed of 900 r / min for 12 seconds, and then spin coating again at a rotation speed of 2800 r / min for 35 seconds; the second heat treatment includes first keeping warm at 140°C for 12 minutes, then annealing at 280°C for 40 minutes, and finally post-annealing at 280°C for 2.5 hours.

[0071] Wherein, the gallium oxide precursor solution is prepared in the following manner:

[0072] Gallium nitrate was added to dimethoxyethanol, shaken and mixed for 5 minutes, then heated to 80°C, and treated at a stirring speed of 1800 r / min for 2.5 hours, and finally left at room temperature for 22 hours to obtain a gallium oxide precursor solution.

[0073] The concentration of metal ions in the gallium oxide precursor solution is 1 mol / L.

[0074] The gallium oxide precursor solution dripped onto the substrate was 40 μL.

[0075] The indium gallium zinc oxide precursor solution is prepared in the following manner:

[0076] Gallium nitrate, zinc nitrate and indium nitrate were added to dimethoxyethanol in a metal ion molar ratio of 1:1:1, shaken and mixed for 5 minutes, then heated to 80°C and treated at a stirring speed of 1800 r / min for 2.5 hours, and finally filtered through an organic filter medium with a pore size of 0.22 µm to obtain an indium gallium zinc oxide precursor solution.

[0077] In the indium gallium zinc oxide precursor solution, the total concentration of metal ions is 2 mol / L.

[0078] The amount of the indium gallium zinc oxide precursor solution dripped onto the metal electrode was 90 μL.

[0079] Depositing a metal electrode on the surface of the gallium oxide polycrystalline film comprises:

[0080] A mask is covered on the surface of the gallium oxide polycrystalline film, and then a metal electrode is deposited by sputtering deposition. The metal electrode is a gold electrode and the substrate is a sapphire substrate.

[0081] Example 2

[0082] A method for preparing a day-blind ultraviolet photodetector. Different from Example 1, the first spin coating and the second spin coating in this embodiment both include: pre-spin coating at a rotation speed of 1100 r / min for 8 seconds, and then spin coating again at a rotation speed of 3200 r / min for 25 seconds. The rest is the same as Example 1.

[0083] Example 3

[0084] A method for preparing a day-blind ultraviolet photodetector. Different from Example 1, the first spin coating and the second spin coating in this embodiment both include: pre-spin coating at a speed of 1000 r / min for 10 seconds, and then spin coating again at a speed of 3000 r / min for 30 seconds. The rest is the same as Example 1.

[0085] Example 4

[0086] A method for preparing a solar-blind ultraviolet photodetector. Different from Example 1, the first heat treatment in this embodiment includes first keeping warm at 220°C for 8 minutes, then heating to 550°C and keeping warm for 20 minutes, and finally annealing at 700°C for 2.5 hours. The rest is the same as Example 1.

[0087] Example 5

[0088] A method for preparing a solar-blind ultraviolet photodetector. Different from Example 1, the first heat treatment in this embodiment includes first keeping warm at 200°C for 10 minutes, then heating to 500°C for 15 minutes, and finally annealing at 650°C for 2 hours. The rest is the same as Example 1.

[0089] Example 6

[0090] A method for preparing a day-blind ultraviolet photodetector. The difference from Example 1 is that the second heat treatment in this embodiment includes first keeping warm at 160°C for 8 minutes, then annealing at 320°C for 20 minutes, and finally post-annealing at 320°C for 1.5 hours. The rest is the same as Example 1.

[0091] Example 7

[0092] A method for preparing a day-blind ultraviolet photodetector. The difference from Example 1 is that the second heat treatment in this embodiment includes first keeping warm at 150°C for 10 minutes, then annealing at 300°C for 30 minutes, and finally post-annealing at 300°C for 2 hours. The rest is the same as Example 1.

[0093] Example 8

[0094] A method for preparing a solar-blind ultraviolet photodetector. The difference from Example 1 is that in this embodiment, the metal ion concentration in the gallium oxide precursor solution is 0.3 mol / L, and the gallium oxide precursor solution added dropwise to the substrate is 55 μL. The rest is the same as Example 1.

[0095] Example 9

[0096] A method for preparing a solar-blind ultraviolet photodetector. The difference from Example 1 is that in this embodiment, the metal ion concentration in the gallium oxide precursor solution is 0.8 mol / L, and the gallium oxide precursor solution added dropwise to the substrate is 45 μL. The rest is the same as Example 1.

[0097] Example 10

[0098] A method for preparing a solar-blind ultraviolet photodetector. The difference from Example 1 is that in this embodiment, the metal ion concentration in the gallium oxide precursor solution is 0.5 mol / L, and the gallium oxide precursor solution added dropwise to the substrate is 50 μL. The rest is the same as Example 1.

[0099] Embodiment 11

[0100] A method for preparing a day-blind ultraviolet photodetector. Different from Example 1, the gallium oxide precursor solution in this example is prepared in the following manner: gallium nitrate is added to dimethoxyethanol, oscillated and mixed for 10 min, then heated to 60°C, and treated at a stirring speed of 2200 r / min for 1.5 h, and finally allowed to stand at room temperature for 26 h to obtain a gallium oxide precursor solution. The rest is the same as Example 1.

[0101] Example 12

[0102] A method for preparing a day-blind ultraviolet photodetector. Different from Example 1, the gallium oxide precursor solution in this example is prepared in the following manner: gallium nitrate is added to dimethoxyethanol, oscillated and mixed for 8 minutes, then heated to 70°C, and treated at a stirring speed of 2000 r / min for 2 hours, and finally placed at room temperature for 24 hours to obtain a gallium oxide precursor solution. The rest is the same as Example 1.

[0103] Embodiment 13

[0104] A method for preparing a solar-blind ultraviolet photodetector, which is different from Example 1 in that an indium gallium zinc oxide precursor solution in this embodiment is prepared in the following manner: gallium nitrate, zinc nitrate, and indium nitrate are added to dimethoxyethanol in a metal ion molar ratio of 1:1:1, and the mixture is shaken and mixed for 10 min, then heated to 60°C, and treated at a stirring speed of 2200 r / min for 1.5 h, and finally filtered using an organic filter medium with a pore size of less than 0.22 µm to obtain an indium gallium zinc oxide precursor solution, and the rest is the same as Example 1.

[0105] Embodiment 14

[0106] A method for preparing a solar-blind ultraviolet photodetector, which is different from Example 1 in that an indium gallium zinc oxide precursor solution is prepared in the following manner: gallium nitrate, zinc nitrate, and indium nitrate are added to dimethoxyethanol in a metal ion molar ratio of 1:1:1, and the mixture is shaken and mixed for 8 minutes, then heated to 70°C, and treated at a stirring speed of 2000 r / min for 2 hours, and finally filtered using an organic filter medium with a pore size of less than 0.22 µm to obtain an indium gallium zinc oxide precursor solution, and the rest is the same as Example 1.

[0107] Embodiment 15

[0108] A method for preparing a solar-blind ultraviolet photodetector, which is different from Example 1 in that the total concentration of metal ions in the indium gallium zinc oxide precursor solution in this embodiment is 1.3 mol / L, and the indium gallium zinc oxide precursor solution added dropwise to the metal electrode is 105 μL, and the rest is the same as Example 1.

[0109] Example 16

[0110] A method for preparing a solar-blind ultraviolet photodetector, which is different from Example 1 in that the total concentration of metal ions in the indium gallium zinc oxide precursor solution in this embodiment is 1.8 mol / L, and the indium gallium zinc oxide precursor solution added dropwise to the metal electrode is 95 μL, and the rest is the same as Example 1.

[0111] Embodiment 17

[0112] A method for preparing a solar-blind ultraviolet photodetector, which is different from Example 1 in that the total concentration of metal ions in the indium gallium zinc oxide precursor solution in this embodiment is 1.5 mol / L, and the indium gallium zinc oxide precursor solution added dropwise to the metal electrode is 100 μL, and the rest is the same as Example 1.

[0113] Embodiment 18

[0114] A method for preparing a day-blind ultraviolet photodetector. Different from Example 1, the gallium oxide precursor solution in this example is prepared in the following manner: gallium nitrate is added to dimethoxyethanol, oscillated and mixed for 15 min, then heated to 50°C, and treated at a stirring speed of 1500 r / min for 3 h, and finally allowed to stand at room temperature for 20 h to obtain a gallium oxide precursor solution. The rest is the same as Example 1.

[0115] Embodiment 19

[0116] A method for preparing a solar-blind ultraviolet photodetector, which is different from Example 1 in that an indium gallium zinc oxide precursor solution is prepared in the following manner: gallium nitrate, zinc nitrate, and indium nitrate are added to dimethoxyethanol at a metal ion molar ratio of 1:1:1, and the mixture is shaken and mixed for 3 minutes, then heated to 90°C, and treated at a stirring speed of 1500 r / min for 1 hour, and finally filtered using an organic filter medium with a pore size of less than 0.22 µm to obtain an indium gallium zinc oxide precursor solution, and the rest is the same as Example 1.

[0117] Embodiment 20

[0118] A method for preparing a solar-blind ultraviolet photoelectric detector comprises the following steps:

[0119] S1, first spin coating a gallium oxide precursor solution on a substrate, and obtaining a gallium oxide polycrystalline thin film after a first heat treatment; wherein the first spin coating includes pre-spin coating at a speed of 1000 r / min for 10 seconds, and then spin coating again at a speed of 3000 r / min for 30 seconds; the first heat treatment includes first keeping the temperature at 200° C. for 10 minutes, then heating to 500° C. for 15 minutes, and finally annealing at 650° C. for 2 hours;

[0120] S2, depositing a metal electrode on the surface of the gallium oxide polycrystalline thin film;

[0121] S3. Spin-coating an indium gallium zinc oxide precursor solution on the metal electrode for the second time, and obtaining a day-blind ultraviolet photodetector after a second heat treatment; wherein the second spin coating includes pre-spin coating at a rotation speed of 1000 r / min for 10 seconds, and then spin coating again at a rotation speed of 3000 r / min for 30 seconds; the second heat treatment includes first keeping warm at 150°C for 10 minutes, then annealing at 300°C for 30 minutes, and finally post-annealing at 300°C for 2 hours.

[0122] Wherein, the gallium oxide precursor solution is prepared in the following manner:

[0123] Gallium nitrate was added to dimethoxyethanol, shaken and mixed for 5 minutes, then heated to 70°C, and treated at a stirring speed of 2000 r / min for 2 hours, and finally left at room temperature for 24 hours to obtain a gallium oxide precursor solution.

[0124] The concentration of metal ions in the gallium oxide precursor solution is 0.5 mol / L.

[0125] The gallium oxide precursor solution dripped onto the substrate was 50 μL.

[0126] The indium gallium zinc oxide precursor solution is prepared in the following manner:

[0127] Gallium nitrate, zinc nitrate and indium nitrate were added to dimethoxyethanol in a metal ion molar ratio of 1:1:1, shaken and mixed for 5 minutes, then heated to 70°C and treated at a stirring speed of 2000r / min for 2 hours, and finally filtered through an organic filter medium with a pore size of 0.22µm to obtain an indium gallium zinc oxide precursor solution.

[0128] In the indium gallium zinc oxide precursor solution, the total concentration of metal ions is 1.5 mol / L.

[0129] The indium gallium zinc oxide precursor solution dripped onto the metal electrode is 100 μL.

[0130] Depositing a metal electrode on the surface of the gallium oxide polycrystalline film comprises:

[0131] A mask is covered on the surface of the gallium oxide polycrystalline film, and then a metal electrode is deposited by sputtering deposition. The metal electrode is a gold electrode and the substrate is a sapphire substrate.

[0132] Figure 1-Figure 8 This is a test diagram of the day-blind ultraviolet photodetector of Example 20. Figure 5 The Sapphire in the formula represents the sapphire substrate. Figure 1 and Figure 2 It can be seen that the surfaces of the prepared gallium oxide and indium gallium zinc oxide films are smooth and dense, and the gallium oxide film is in a polycrystalline state. Figure 4 It shows that in addition to the peak corresponding to the substrate sapphire, the XRD analysis of the gallium oxide / indium gallium zinc oxide heterojunction and the gallium oxide film shows that in addition to the same characteristic peaks, the characteristic peaks related to gallium oxide show a mixed state of α and β gallium oxide. There is no obvious characteristic peak related to IGZO. Figure 5 This can further confirm that the IGZO film has no obvious corresponding characteristic peaks, showing an amorphous state.

[0133] Comparative Example 1

[0134] A method for preparing a solar-blind ultraviolet photoelectric detector comprises the following steps:

[0135] A gallium oxide precursor solution is first spin-coated on the substrate, and a gallium oxide polycrystalline film is obtained after a first heat treatment; wherein the first spin coating includes pre-spin coating at a rotation speed of 900 r / min for 12 seconds, and then spin coating again at a rotation speed of 2800 r / min for 35 seconds; the first heat treatment includes first keeping warm at 180°C for 12 minutes, then heating to 450°C for 20 minutes, and finally annealing at 600°C for 2.5 hours.

[0136] Wherein, the gallium oxide precursor solution is prepared in the following manner:

[0137] Gallium nitrate was added to dimethoxyethanol, shaken and mixed for 5 minutes, then heated to 80°C, and treated at a stirring speed of 1800 r / min for 2.5 hours, and finally left at room temperature for 22 hours to obtain a gallium oxide precursor solution.

[0138] The concentration of metal ions in the gallium oxide precursor solution is 1 mol / L.

[0139] The gallium oxide precursor solution dripped onto the substrate was 40 μL.

[0140] Comparative Example 2

[0141] A method for preparing a solar-blind ultraviolet photoelectric detector comprises the following steps:

[0142] A second spin coating of an indium gallium zinc oxide precursor solution is performed on the substrate, and a second heat treatment is performed to obtain a day-blind ultraviolet photodetector; wherein the second spin coating includes pre-spin coating at a rotation speed of 900 r / min for 12 seconds, and then spin coating again at a rotation speed of 2800 r / min for 35 seconds; the second heat treatment includes first keeping warm at 140°C for 12 minutes, then annealing at 280°C for 40 minutes, and finally post-annealing at 280°C for 2.5 hours.

[0143] The indium gallium zinc oxide precursor solution is prepared in the following manner:

[0144] Gallium nitrate, zinc nitrate and indium nitrate were added to dimethoxyethanol in a metal ion molar ratio of 1:1:1, shaken and mixed for 5 minutes, then heated to 80°C and treated at a stirring speed of 1800 r / min for 2.5 hours, and finally filtered through an organic filter medium with a pore size of 0.22 µm to obtain an indium gallium zinc oxide precursor solution.

[0145] In the indium gallium zinc oxide precursor solution, the total concentration of metal ions is 2 mol / L.

[0146] The amount of the indium gallium zinc oxide precursor solution dripped onto the metal electrode was 90 μL.

[0147] Comparative Example 3

[0148] A method for preparing a solar-blind ultraviolet photoelectric detector comprises the following steps:

[0149] A metal electrode is deposited on a sapphire substrate by sputtering deposition, and the metal electrode is a gold electrode; a sapphire substrate is placed, and a high-purity gold foil is used as a target material, and a current is applied to the target material for direct current sputtering until a dense and continuous interdigital electrode is formed on the surface;

[0150] Then, magnetron sputtering was used to sputter the indium gallium zinc oxide film; the sputtering power was 90W, the working gas pressure was 4.1mTorr, the gas flow rate was 20SCCM, and the sputtering time was 2 minutes and 22 seconds;

[0151] Finally, the gallium oxide film was sputtered by magnetron sputtering; the sputtering power was 90 W, the working gas pressure was 4.1 mTorr, the gas flow rate was 20 SCCM, and the sputtering time was 6 minutes and 9 seconds.

[0152] Table 1 shows the performance test results of the solar-blind ultraviolet photodetectors prepared in the above embodiments and comparative examples.

[0153]

[0154] Although the present invention has been illustrated and described with specific embodiments, it will be appreciated that many other changes and modifications may be made without departing from the spirit and scope of the present invention. Therefore, it is intended to include all such changes and modifications within the scope of the present invention in the appended claims.

Claims

1. A method for preparing a solar-blind ultraviolet photodetector, characterized in that: The following steps are involved: S1. Spin-coating a gallium oxide precursor solution on a substrate for the first time, and obtaining a gallium oxide polycrystalline thin film after a first heat treatment; wherein the first spin coating includes pre-spin coating at a rotation speed of 900-1100 r / min for 8-12 s, and then spin coating again at a rotation speed of 2800-3200 r / min for 25-35 s; the first heat treatment includes first keeping the temperature at 180-220° C. for 8-12 min, then heating to 450-550° C. for 10-20 min, and finally annealing at 600-700° C. for 1.5-2.5 h; S2, depositing a metal electrode on the surface of the gallium oxide polycrystalline thin film; S3. Spin-coating an indium gallium zinc oxide precursor solution on the metal electrode for the second time, and obtaining a day-blind ultraviolet photodetector after a second heat treatment; wherein the second spin coating includes pre-spin coating at a rotation speed of 900-1100 r / min for 8-12 s, and then spin coating again at a rotation speed of 2800-3200 r / min for 25-35 s; the second heat treatment includes first keeping warm at 140-160°C for 8-12 min, then annealing at 280-320°C for 20-40 min, and finally post-annealing at 280-320°C for 1.5-2.5 h.

2. The method for preparing a solar-blind ultraviolet photodetector according to claim 1, characterized in that: The gallium oxide precursor solution is prepared in the following manner: Gallium nitrate is added to dimethoxyethanol, shaken and mixed for 5-10 minutes, then heated to 60-80°C, and treated at a stirring speed of 1800-2200 r / min for 1.5-2.5 hours, and finally left at room temperature for 22-26 hours to obtain a gallium oxide precursor solution.

3. The method for preparing a solar-blind ultraviolet photodetector according to claim 1, characterized in that: In the gallium oxide precursor solution, the metal ion concentration is 0.3-0.8 mol / L.

4. The method for preparing a solar-blind ultraviolet photodetector according to claim 1, characterized in that: The gallium oxide precursor solution dripped onto the substrate is 45-55 μL.

5. The method for preparing a solar-blind ultraviolet photodetector according to claim 1, characterized in that: The indium gallium zinc oxide precursor solution is prepared in the following manner: Gallium nitrate, zinc nitrate and indium nitrate are added to dimethoxyethanol in a metal ion molar ratio of 1:1:1, and the mixture is shaken and mixed for 5-10 minutes, then heated to 60-80°C, and treated at a stirring speed of 1800-2200 r / min for 1.5-2.5 hours, and finally filtered through an organic filter medium with a pore size of less than 0.22 µm to obtain an indium gallium zinc oxide precursor solution.

6. The method for preparing a solar-blind ultraviolet photodetector according to claim 1, characterized in that: In the indium gallium zinc oxide precursor solution, the total concentration of metal ions is 1.3-1.8 mol / L.

7. The method for preparing a solar-blind ultraviolet photoelectric detector according to claim 1, characterized in that: The indium gallium zinc oxide precursor solution dripped onto the metal electrode is 95-105 μL.

8. The method for preparing a solar-blind ultraviolet photoelectric detector according to any one of claims 1 to 7, characterized in that: Depositing a metal electrode on the surface of the gallium oxide polycrystalline film comprises: A mask is covered on the surface of the gallium oxide polycrystalline film, and then a metal electrode is deposited by sputtering deposition.

9. A solar-blind ultraviolet photodetector prepared by the method for preparing a solar-blind ultraviolet photodetector according to any one of claims 1 to 8.

10. Application of the solar-blind ultraviolet photoelectric detector according to claim 9 in flame monitoring, missile early warning or space communication.

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