Infrared detector and preparation method thereof

Abstract

The invention provides an infrared detector and a preparation method thereof. The infrared detector comprises a substrate, an electrode, a thermosensitive layer and a composite absorption layer, wherein the thermosensitive layer and the composite absorption layer are sequentially arranged in the thickness direction of the substrate, and the thermosensitive layer is made of manganese cobalt nickel oxide; part of the surface of the electrode is in contact with the substrate, and part of the surface of the electrode is in contact with the thermosensitive layer; the composite absorption layer comprises a first light absorption layer and a second light absorption layer which are sequentially arranged in the direction away from the thermosensitive layer. The second light absorption layer comprises nanostructures and a cavity defined by a plurality of adjacent nanostructures, the nanostructures extend and grow in the direction away from the first light absorption layer from the bottom ends, making contact with the first light absorption layer, of the nanostructures, and the included angle between the extending direction of the nanostructures and the axial direction of the first light absorption layer is 0-70 degrees; the first light absorbing layer can absorb light penetrating through the second light absorbing layer and is used for electrically isolating the composite absorbing layer from the thermosensitive layer. The infrared detector provided by the invention is relatively low in thermal mass, relatively high in response speed and excellent in light absorptivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of infrared detection, and particularly relates to an infrared detector and a preparation method thereof. Background Art

[0002] Infrared radiation, as an electromagnetic wave containing rich information, is invisible to the human eye. Infrared detection technology can convert infrared radiation into physical quantities that people can recognize to achieve infrared detection. In an infrared system, an infrared detector, as the key to detecting and identifying targets, mainly functions to convert invisible incident infrared radiation into readable electrical signals. In recent years, researchers have been committed to developing various new, high-performance, low-cost, multi-functional, multi-parameter, and highly stable infrared detectors.

[0003] The microbolometer-type uncooled infrared detector relies on the infrared thermal effect. Its working principle is that when incident infrared radiation is absorbed by the device, light energy is converted into heat energy, and the heat energy causes a change in the resistivity of the thermosensitive material in the detector. The corresponding current or voltage change is read out through the connected circuit, thereby achieving infrared detection. It has the advantages of a wide response band, simple structure, low cost, room-temperature operation, good long-term stability, etc., and does not require a large and expensive refrigeration system during operation, making the device more portable. In recent years, this type of infrared detector has attracted significant research interest and has been widely used in fields such as medical imaging, environmental monitoring, remote sensing detection, spectral detection, communication, fire detection, gas detection and identification.

[0004] The thermosensitive materials used for preparing microbolometer-type uncooled infrared detectors mainly include semiconductor materials, metal materials, and superconducting materials, etc. Among them, metal oxide semiconductor materials are one of the important thermosensitive materials. In recent years, commonly used metal oxide materials include, for example, VO X , La 1-X A X MnO3 (A = Ca, Sr, Ba, Pb) and Mn-Co-Ni-O spinel materials, etc.

[0005] Among them, the Mn-Co-Ni-O (denoted as MCNO) spinel thermosensitive material has a relatively high negative temperature coefficient of resistance (NTCR) value (−3% / K to −5% / K) in a wide temperature range from 230K to 400K, a suitable resistivity (≈10 2 -10 3 Ω·cm), and at the same time, this material has a high degree of freedom in adjusting its electrical properties and good long-term stability, showing greater advantages than other materials. It has been widely studied and applied in earth radiation budget measurement, temperature measurement, temperature compensation, current surge suppression, and uncooled infrared detection.

[0006] In recent years, with the rapid development of thin film preparation technology, thin film thermal infrared detectors have been widely used in various fields of society. The light absorption characteristics of infrared detectors are key parameters for evaluating infrared detectors. The greater the light absorption rate of the device, the higher the responsivity and the better the detection performance. However, the MCNO thin film material itself has weak absorption in the IR atmospheric window range, and the absorption rate of the material itself is low, which affects the improvement of the device detection performance. Although the absorption rate of the thin film can be increased to about 50% by increasing the thin film thickness to 10 μm, the improvement is limited. Moreover, blindly increasing the thin film thickness will lead to an increase in the overall thermal mass of the device and affect the response speed of the device. Summary of the Invention

[0007] To solve all or part of the above technical problems, the present invention provides the following technical solutions: One object of the present invention is to provide an infrared detector, which includes: a substrate, an electrode, and a thermosensitive layer and a composite absorption layer sequentially disposed in the thickness direction of the substrate. The material of the thermosensitive layer includes manganese cobalt nickel oxide; a part of the surface of the electrode is in contact with the substrate, and a part of the surface is in contact with the thermosensitive layer; The composite absorption layer includes a first light absorption layer and a second light absorption layer sequentially disposed in a direction away from the thermosensitive layer; the second light absorption layer includes nanostructures and cavities formed by surrounding of a plurality of adjacent nanostructures. The nanostructures extend and grow in a direction away from the first light absorption layer from the bottom end in contact with the first light absorption layer, and the included angle between the extending direction of the nanostructures and the axial direction of the first light absorption layer is 0-70°; the first light absorption layer can absorb the light transmitted through the second light absorption layer and is used to electrically isolate the composite absorption layer and the thermosensitive layer.

[0008] The light absorption rate of the MCNO thermosensitive material itself is relatively low, and the optoelectronic response performance of the infrared detector based on the MCNO thermosensitive material is insufficient. In the infrared detector of the present invention, the extending direction of the nanostructures in the second light absorption layer forms a preset angle, and the nanostructures act as wall materials to enclose many tiny cavities. When the incident light acts on the surface of the device, the incident radiation undergoes multiple reflections in the cavities, increasing the propagation path of the incident light and being gradually absorbed in the structure, thereby enhancing the absorption of the incident light by the device and improving the optoelectronic response ability of the device. However, the present invention finds that some incident light will still pass through the second light absorption layer, which results in the insufficient absorption of the incident light by the second light absorption layer alone. Therefore, the present invention sets a composite absorption structure in which the first light absorption layer and the second light absorption layer are stacked, so that the first light absorption layer further absorbs the light transmitted through the second light absorption layer, which can further improve the overall light absorption rate of the device; at the same time, the first light absorption layer is disposed between the second light absorption layer and the thermosensitive layer and can be used to electrically isolate the composite absorption layer and the thermosensitive layer.

[0009] In some embodiments, the thickness of the thermosensitive layer is 0.1-10 μm, the thickness of the first light-absorbing layer is 100-300 nm, and the vertical thickness of the second light-absorbing layer is 0.2-0.5 μm. The present invention finds that the thicknesses of the thermosensitive layer, the first light-absorbing layer, and the second light-absorbing layer have an impact on the overall thermal mass of the device. If the thickness is too large, the thermal mass of the device increases, which will slow down the response speed of the device; if the thickness is small, the absorption rate is small. Through systematic research, it is found that when the thicknesses of the thermosensitive layer, the first light-absorbing layer, and the second light-absorbing layer are simultaneously controlled within the above ranges, not only the absorption rate of the composite light-absorbing layer is excellent, but also the overall thermal mass of the device can be made lower, thus having a faster response speed.

[0010] In some embodiments, the material of the first light-absorbing layer includes one or a combination of SiO2, Al2O3, and Si3N4 insulating media. The first light-absorbing layer of these materials can cooperate with the second light-absorbing layer to produce an excellent light absorption effect.

[0011] In some embodiments, the included angle between the extending direction of the nanostructure and the axis perpendicular to the second light-absorbing layer is 50-60°.

[0012] In some embodiments, the porosity of the second light-absorbing layer is 0-80%, preferably 30% to 80%. The absorption efficiency of the second light-absorbing layer is related to the cavity density it contains. By adjusting the deposition angle and the rotation speed of the sample stage during deposition, the porosity of the second light-absorbing layer can be adjusted. The higher the porosity, the higher the light absorption efficiency.

[0013] In some embodiments, the material of the nanostructure is a metal element or an alloy.

[0014] In some embodiments, the metal element includes Au, Ag, Cu, Ti, Ni, Cr, Al, or W; the alloy is a binary or multi-component alloy containing NiCr, a binary or multi-component alloy containing NiFe, or a binary or multi-component alloy containing NiCu. The multi-component alloy refers to an alloy that contains one or more other metals or non-metals in addition to NiCr, NiFe, and NiCu.

[0015] In some embodiments, the morphology of the nanostructure is nanocolumnar, helical, or zigzag.

[0016] The second object of the present invention is to provide a preparation method for the infrared detector described in any one of the above, including: Forming a thermosensitive layer with a material including manganese cobalt nickel oxide on a substrate; Forming a first light-absorbing layer on the thermosensitive layer and fabricating electrodes at opposite ends of the thermosensitive layer to obtain an intermediate structure; A nanostructure is formed on the first light-absorbing layer of the intermediate structure by an electron beam deposition method, including: placing the intermediate structure on a sample stage, and adjusting the angle between the normal direction of the sample stage and the normal of the evaporation source for electron beam inclined angle deposition to be 0 - 90°, so that the included angle between the extending direction of the grown nanostructure and the axis of the first light-absorbing layer is 0 - 70°, and a plurality of adjacent nanostructures enclose to form a cavity, thereby forming a second light-absorbing layer.

[0017] In some embodiments, the sample stage is kept stationary or rotated at a preset speed, and the preset speed is greater than 0 and less than or equal to 10 rpm. By adjusting the angle between the normal of the evaporation source and the normal of the sample stage and the rotation rate of the sample stage during deposition, the formed nanostructure can have a vertical nanocolumnar, helical or zigzag shape, and the surface of the second light-absorbing layer presents a porous morphology; and the cavity density, that is, the porosity of the second light-absorbing layer, can be adjusted by adjusting the rotation speed of the sample stage.

[0018] In some preferred embodiments, the angle between the normal direction of the sample stage and the normal of the evaporation source for electron beam inclined angle deposition is 70 - 90°, and the sample stage rotates at a speed of 0 - 10 rpm, so that the porosity of the deposited second light-absorbing layer is 30 - 80%.

[0019] The method of forming the thermosensitive layer on the substrate can adopt any method known in the art, such as chemical solution spin coating, evaporation, sputtering and other methods, and the present invention does not make special limitations thereon.

[0020] The method of forming the first light-absorbing layer on the thermosensitive layer can adopt any method known in the art, such as PECVD, evaporation, sputtering and other methods, and the present invention does not make special limitations thereon.

[0021] The method of fabricating the electrode can adopt any method known in the art, such as electron beam evaporation and other methods, and the present invention does not make special limitations thereon.

[0022] The substrate can be any material known in the art and suitable for any substrate of manganese cobalt nickel oxide, such as sapphire substrate, thermally oxidized silicon substrate, etc.

[0023] In some embodiments, the method further includes: using photolithography technology to form a preset pattern on the thermosensitive layer, the first light-absorbing layer, and the second light-absorbing layer.

[0024] In some embodiments, the method further includes: using photolithography technology to array the second light-absorbing layer.

[0025] In some embodiments, the preparation method of the infrared detector includes the following steps: (1) Prepare a manganese-cobalt-nickel oxide thermosensitive layer with a thickness of 0.1 - 10 μm on a sapphire or thermally oxidized silicon substrate. The preparation method can be any one or more of magnetron sputtering, electron beam evaporation, or chemical solution spin coating; (2) On the surface of the manganese-cobalt-nickel oxide thermosensitive layer, according to the pattern defined by lithography, after exposure and development, use ion beam dry etching to etch the manganese-cobalt-nickel oxide thermosensitive layer into a thermosensitive layer micro-table with specific dimensions and specific shapes; (3) Grow a first light-absorbing layer with a thickness of 100 - 300 nm on the surface of the thermosensitive layer micro-table; (4) According to the pattern defined by lithography, after exposure and development, use the RIE reactive ion etching method to etch the first light-absorbing layer into a first light-absorbing layer micro-table with specific dimensions and specific shapes, and expose the electrode regions on both sides; (5) At both ends of the manganese-cobalt-nickel oxide thermosensitive layer, define the electrode pattern by lithography. After exposure and development, use the electron beam evaporation method to deposit the electrode layer to form an intermediate structure; (6) Above the first light-absorbing layer, according to the pattern defined by lithography, after exposure and development, use the electron beam deposition method described above to prepare a second light-absorbing layer with a vertical thickness of 0.2 - 0.5 μm. Specifically, place the intermediate structure on the sample stage, by adjusting the angle between the normal direction of the sample stage and the normal of the evaporation source of the electron beam deposition between 0 - 90°, and optionally adjusting the rotation speed of the sample stage to 0 rpm - 10 rpm, so that the extension direction of the grown nanostructure and the axis of the first light-absorbing layer form an angle between 0 - 70°, and a cavity is formed by surrounding multiple adjacent nanostructures, thereby forming the second light-absorbing layer.

[0026] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention provides an infrared detector with a lower thermal mass, a faster response speed, and an excellent light absorption rate. By adjusting the thickness of the thermosensitive layer and the composite absorption layer, the infrared detector has a high light absorption rate on the premise of a lower overall thermal mass. Its high light absorption rate benefits from the composite absorption structure formed by the first light-absorbing layer, the second light-absorbing layer, and the thermosensitive layer. The first light-absorbing layer and the thermosensitive layer further absorb the light passing through the second light-absorbing layer, further improving the overall light absorption rate of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings described below are only some embodiments recorded in the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0028] Figure 1It is the process flow chart for preparing an infrared detector in Example 1; Figure 2 It is the schematic structural diagram of the infrared detector obtained in Example 1; Figure 3 It is the side view of the structure of the infrared detector obtained in Example 1; Figure 4 It is the surface topography diagram of the second light-absorbing layer in Example 1; Figure 5 It is the cross-sectional topography diagram of the infrared detector in Example 1; Figure 6 It is the surface topography diagram of the second light-absorbing layer in Example 3; Figure 7 It is the cross-sectional topography diagram of the infrared detector in Example 3; Figure 8 It is the light absorption rate comparison diagram of the infrared detector in Example 1, the infrared detector in Comparative Example 1, and the single second absorption layer in Example 1; Figure 9 It is the response current comparison diagram of the infrared detector (device with an absorption layer) in Example 1 and the infrared detector in Comparative Example 1 (device without an absorption layer) under the action of a 1550 nm wavelength laser. Detailed implementation manners

[0029] The technical solutions of the present invention will be described in detail below in conjunction with specific embodiments, so that those skilled in the art can better understand and implement the technical solutions of the present invention. The specific functional details disclosed herein should not be construed as restrictive, but only as the basis of the claims and as a representative basis for teaching those skilled in the art to adopt the present invention in any appropriate detailed embodiment in different ways.

[0030] In addition, unless otherwise specified, various raw materials used in the following examples can be obtained from the market or other channels, and various production and testing equipment used are also equipment known in the art, and the testing methods used are also methods known in the art.

[0031] Example 1 This example provides an infrared detector and a preparation method thereof, Figure 1 It is the preparation flow chart of this example, specifically including the following steps: (1) Depositing a manganese cobalt nickel oxide thermosensitive layer: Place the sapphire substrate in a solution of concentrated H2SO4:H2O2 = 3:1, heat it to 100 °C and keep it for 1 h, and place the sample and raw materials in a vacuum chamber. Prepare a manganese cobalt nickel oxide thermosensitive layer on the sapphire substrate by magnetron sputtering - electron beam evaporation multi-layer film solidification method, and set the vacuum degree to 5×10 -5Pa, the deposition temperature was 400 °C, the deposition time was 5 h, and a manganese-cobalt-nickel oxide thermosensitive layer with a thickness of 0.3 μm was prepared.

[0032] (2) Manganese-cobalt-nickel oxide micro-table etching: According to the pattern defined by photolithography on the surface of manganese-cobalt-nickel oxide, after exposure and development, dry etching with an ion beam was used to etch the manganese-cobalt-nickel oxide thin film into a square micro-table with a size of 400×400 μm 2 of the square micro-table.

[0033] (3) SiO2 layer growth: SiO2 was grown on the surface of the manganese-cobalt-nickel oxide thermosensitive layer by the PECVD method. The growth temperature was 350 °C, and a first light-absorbing layer with a thickness of 0.2 μm and a material of SiO2 was prepared.

[0034] (4) SiO2 layer etching: According to the pattern defined by photolithography, after exposure and development, the RIE reactive ion etching method was used to etch the SiO2 thin film into a square micro-table with a size of 400×290 μm 2 covering the manganese-cobalt-nickel oxide thermosensitive layer and exposing the electrode regions on both sides.

[0035] (5) Electrode layer preparation: At both ends of the manganese-cobalt-nickel oxide thermosensitive layer, the electrode pattern was defined by photolithography. After exposure and development, the Cr / Au electrode layer was deposited by electron beam evaporation to form an electrode layer with a thickness of Cr 20 nm + Au 200 nm.

[0036] (6) Preparation of the second light-absorbing layer: Above the SiO2 layer, according to the pattern defined by photolithography, after exposure and development, a porous metal nanostructure thin film was prepared by electron beam oblique deposition method. NiCr alloy was used as the deposition material, and the angle between the normal direction of the sample stage and the normal direction of the evaporation source was 83°. The structure prepared in step (5) was placed on the sample stage and the rotation speed was set to 0 rpm for deposition. The deposition thickness was 200 nm in the direction perpendicular to the SiO2 layer to obtain the second light-absorbing layer. This second light-absorbing layer has a nanostructure of nanocolumns and cavities. The nanocolumn structure grows obliquely, and the included angle between its extension direction and the axial direction of the SiO2 layer is 56.8°. And a cavity is formed by the surrounding of multiple adjacent nanocolumn structures. The porosity of the second light-absorbing layer is about 43.2%. Figure 4 is the surface topography diagram of the second light-absorbing layer in Example 1.

[0037] Figure 2 is the schematic structural diagram of the infrared detector prepared in this example, Figure 3 is the side view of the structure of the prepared infrared detector. Please refer to Figure 2 、 Figure 3, the infrared detector prepared in this embodiment includes a substrate 5, a manganese cobalt nickel oxide thermosensitive layer 3 formed on the substrate 5, electrodes 4 located at both ends of the manganese cobalt nickel oxide thermosensitive layer 3, a SiO2 layer 2 formed on the manganese cobalt nickel oxide thermosensitive layer 3, and a second light-absorbing layer 1 formed on the SiO2 layer. Figure 5 is the cross-sectional morphology diagram of the infrared detector prepared in this embodiment.

[0038] In this embodiment 1, the absorption rate of the device in the range of 800 - 1800 nm is about 60% (1800 nm) - 80% (800 nm), and the response time is about 56 ms.

[0039] Embodiment 2 (1) Depositing the manganese cobalt nickel oxide thermosensitive layer: Place the sapphire substrate in a solution of concentrated H2SO4:H2O2 = 3:1, heat it to 100 °C and keep it for 1 h, and place the sample and the raw materials in a vacuum chamber. Use the magnetron sputtering - electron beam evaporation multi-layer film solidification method to prepare the manganese cobalt nickel oxide thermosensitive layer on the sapphire substrate. Set the vacuum degree to 5×10 -5 Pa, the deposition temperature is 400 °C, the deposition time is 1.5 h, and a manganese cobalt nickel oxide thermosensitive layer with a thickness of 0.3 μm is prepared.

[0040] (2) Etching the manganese cobalt nickel oxide micro-table: According to the pattern defined by photolithography on the surface of the manganese cobalt nickel oxide, after exposure and development, use the dry etching of ion beam to etch the manganese cobalt nickel oxide thin film into a square micro-table with a size of 600×600 μm 2 square micro-table.

[0041] (3) Growing the SiO2 layer: Use the PECVD method to grow the SiO2 layer on the surface of the manganese cobalt nickel oxide thermosensitive layer. The growth temperature is 350 °C, and a SiO2 layer with a thickness of 0.2 μm is prepared, which is the first absorption layer.

[0042] (4) Etching the SiO2 layer: According to the pattern defined by photolithography, after exposure and development, use the RIE reactive ion etching method to etch the SiO2 thin film into a square micro-table with a size of 600×490 μm 2 square micro-table covering the manganese cobalt nickel oxide thermosensitive layer and exposing the electrode regions on both sides.

[0043] (5) Preparing the electrode layer: At both ends of the manganese cobalt nickel oxide thermosensitive layer, define the electrode pattern by photolithography. After exposure and development, use the electron beam evaporation method to deposit the Cr / Au electrode layer to form an electrode layer with a thickness of Cr 20 nm + Au 200 nm.

[0044] (6)Fabrication of the second light-absorbing layer: Above the SiO2 layer, according to the pattern defined by lithography, after exposure and development, a porous metal nanostructure thin film is prepared by electron beam oblique angle deposition method. Using NiCr alloy as the deposition material, the angle between the normal direction of the sample stage and the normal direction of the evaporation source is 83°. Place the structure obtained in step (5) on the sample stage and set the rotation speed to 0 rpm for deposition. The deposition thickness is 260 nm in the direction perpendicular to the SiO2 layer, obtaining the second light-absorbing layer. This second light-absorbing layer has a nanostructure of nanocolumns and cavities. The nanocolumn structure grows obliquely, and the included angle between its extending direction and the axial direction of the SiO2 layer is 56.8°, and a plurality of adjacent nanocolumn structures surround to form a cavity.

[0045] In this Example 2, the device is only different in size from the device in Example 1, and the absorption rate is basically the same as that in Example 1.

[0046] Example 3 (1)Deposition of the manganese cobalt nickel oxide thermosensitive layer: Place the sapphire substrate in a solution of concentrated H2SO4:H2O2 = 3:1, heat it to 100 °C and keep it for 1 h, and place the sample and raw materials in the vacuum chamber. Use magnetron sputtering method to prepare the manganese cobalt nickel oxide thermosensitive layer on the sapphire substrate. During the preparation process, set the vacuum degree to 5×10 -5 Pa, the deposition temperature is 400 °C, the deposition time is 1.5 h, and a manganese cobalt nickel oxide thermosensitive layer with a thickness of 0.3 μm is obtained.

[0047] (2)Etching of the manganese cobalt nickel oxide micro-table: On the surface of the manganese cobalt nickel oxide, according to the pattern defined by lithography, after exposure and development, use ion beam dry etching to etch the manganese cobalt nickel oxide thin film into a square micro-table with a size of 300×300 μm 2

[0048] (3)Growth of the SiO2 layer: Use PECVD method to grow the SiO2 layer on the surface of the manganese cobalt nickel oxide thermosensitive layer, and the growth temperature is 350 °C, obtaining a SiO2 layer with a thickness of 0.2 μm.

[0049] (4)Etching of the SiO2 layer: According to the pattern defined by lithography, after exposure and development, use RIE reactive ion etching method to etch the SiO2 thin film into a square micro-table with a size of 300×240 μm 2 covering the manganese cobalt nickel oxide thermosensitive layer above and exposing the electrode regions on both sides.

[0050] (5)Fabrication of the electrode layer: At both ends of the manganese cobalt nickel oxide thermosensitive layer, define the electrode pattern by lithography. After exposure and development, use electron beam evaporation method to deposit the Cr / Au electrode layer, forming an electrode layer with a thickness of Cr 20 nm + Au 200 nm.

[0051] (6)Preparation of the second light-absorbing layer: Above the SiO2 layer, according to the pattern defined by lithography, after exposure and development, a porous metal nanostructure thin film is prepared by electron beam oblique angle deposition method. Using NiCr alloy as the deposition material, the angle between the normal direction of the sample stage and the normal direction of the evaporation source is 83°. Place the structure obtained in step (5) on the sample stage and set the rotation speed to 0.03 rpm for deposition. The deposition thickness is 260 nm in the direction perpendicular to the SiO2 layer to obtain the second light-absorbing layer. This second light-absorbing layer has a spiral nanocolumn structure, and a cavity is formed by surrounding multiple adjacent spiral nanocolumn structures. The porosity of the second light-absorbing layer is about 62.27%.

[0052] Figure 6 is the surface morphology diagram of the second light-absorbing layer obtained in this embodiment, Figure 7 is the cross-sectional morphology diagram of the infrared detector obtained in this embodiment.

[0053] In this embodiment 3, the absorption rate of the device in the range of 800 - 1800 nm is about 70% (at 1800 nm) - 80% (at 800 nm), and the response time is about 70 ms.

[0054] Example 4 Example 4 is basically the same as Example 1, except that in Example 4, when depositing the second light-absorbing layer, the angle between the normal direction of the sample stage and the normal direction of the evaporation source is adjusted to 43°, so that the included angle between the nanocolumn structure and the axial direction of the SiO2 layer is about 15°.

[0055] The absorption rate of the infrared detection device in this embodiment is about 25 - 35% in the range of 800 - 1800 nm.

[0056] Example 5 Example 5 is basically the same as Example 1, except that in Example 9, when depositing the second light-absorbing layer, the angle between the normal direction of the sample stage and the normal direction of the evaporation source is adjusted to 63°, so that the included angle between the nanocolumn structure and the axial direction of the SiO2 layer is about 40°.

[0057] The absorption rate of the infrared detection device in this embodiment is about 35 - 45% in the range of 800 - 1800 nm.

[0058] Comparative Example 1 Comparative Example 1 is a traditional MCNO detector. This MCNO detector only has a manganese-cobalt-nickel oxide thermosensitive layer with a thickness of 0.3 μm and does not have the SiO2 first light-absorbing layer and the second light-absorbing layer. The absorption rate of the device in Comparative Example 1 is about 10% (at 1800 nm) - 70% (at 800 nm) in the range of 800 - 1800 nm, and the response time is about 52 ms.

[0059] The present invention tests the relevant performances of the infrared detectors obtained in the above-mentioned embodiments and comparative examples. The test method is as follows: Infrared light is emitted by a 1550-nm laser and acts on the surface of the device. The light source modulation frequency is 1 Hz, and the operating bias voltage of the device is 10 V. Infrared detection is performed by measuring the change in the current at both ends of the device.

[0060] Figure 8 It is a comparison chart of the light absorption rates of the infrared detector in Example 1, the infrared detector in Comparative Example 1, and the separate second absorption layer in Example 1. Figure 9 It is a comparison chart of the response currents of the infrared detector (device with an absorption layer) in Example 1 and the infrared detector in Comparative Example 1 (device without an absorption layer) under the action of a 1550-nm wavelength laser.

[0061] All aspects, embodiments, features, and examples of the present invention should be considered illustrative in all respects and are not intended to limit the present invention. The scope of the present invention is only defined by the claims. Without departing from the spirit and scope of the claimed invention, those skilled in the art will appreciate other embodiments, modifications, and uses.

[0062] In addition, the inventors of this case also referred to the foregoing embodiments and conducted tests using other raw materials, process operations, and process conditions described in this specification, and all obtained relatively ideal results.

[0063] Although the present invention has been described with reference to illustrative embodiments, those skilled in the art will understand that various other changes, omissions, and / or additions can be made without departing from the spirit and scope of the present invention, and the elements of the embodiments can be replaced with substantially equivalent ones. Additionally, many modifications can be made without departing from the scope of the present invention to adapt a particular situation or material to the teachings of the present invention. Therefore, the present invention is not intended to be limited to the specific embodiments disclosed for carrying out the present invention, but is intended to cover all embodiments falling within the scope of the appended claims. Moreover, unless specifically stated, any use of the terms first, second, etc. does not denote any order or importance, but the terms first, second, etc. are used to distinguish one element from another.

Claims

1. An infrared detector, characterized in that, include: A substrate, an electrode, and a thermosensitive layer and a composite absorption layer sequentially arranged in the thickness direction of the substrate, wherein the thermosensitive layer is made of manganese, cobalt, nickel and oxygen; a part of the surface of the electrode is arranged in contact with the substrate, and a part of the surface is arranged in contact with the thermosensitive layer; The composite absorption layer comprises a first light absorption layer and a second light absorption layer which are sequentially arranged in a direction away from the thermosensitive layer; the second light absorption layer comprises a nanostructure and a cavity formed by a plurality of adjacent nanostructures, the nanostructure extends and grows from a bottom end thereof in contact with the first light absorption layer in a direction away from the first light absorption layer, and an angle between the extension direction of the nanostructure and the axial direction of the first light absorption layer is 0-70°; the first light absorption layer can absorb light passing through the second light absorption layer, and is used to electrically isolate the composite absorption layer from the thermosensitive layer.

2. The infrared detector according to claim 1, characterized in that: The thickness of the thermosensitive layer is 0.1-10 μm, the thickness of the first light absorbing layer is 100-300 nm, and the vertical thickness of the second light absorbing layer is 0.2-0.5 μm.

3. The infrared detector according to claim 1, wherein: The material of the first light absorption layer includes one or a combination of SiO2, Al2O3, and Si3N4.

4. The infrared detector according to claim 1, wherein: The porosity of the second light absorbing layer is 0% to 80%, preferably 30% to 80%.

5. The infrared detector according to claim 1, wherein: The material of the nanostructure is a metal element or an alloy.

6. The infrared detector according to claim 5, wherein: The metal element includes Au, Ag, Cu, Ti, Ni, Cr, Al or W; the alloy is a binary or multi-component alloy containing NiCr, a binary or multi-component alloy containing NiFe or a binary or multi-component alloy containing NiCu.

7. The infrared detector according to claim 1, wherein: The nanostructure has a shape of a nano column, a spiral or a zigzag.

8. The method for preparing an infrared detector according to any one of claims 1-7, characterized in that, include: forming a heat-sensitive layer including manganese, cobalt, nickel and oxygen on the substrate; forming a first light absorbing layer on the thermosensitive layer, and fabricating electrodes at opposite ends of the thermosensitive layer to obtain an intermediate structure; The nanostructure is formed on the first light absorbing layer of the intermediate structure by an electron beam deposition method, comprising: placing the intermediate structure on a sample stage, adjusting the angle between the normal direction of the sample stage and the normal direction of the evaporation source of the electron beam deposition to 0-90°, so that the angle between the extension direction of the grown nanostructure and the axial direction of the first light absorbing layer is 0-70°, and a plurality of adjacent nanostructures are surrounded to form a cavity to form a second light absorbing layer.

9. The preparation method according to claim 8, wherein: The sample stage is made to be stationary or rotate at a preset speed, wherein the preset speed is greater than 0 and less than or equal to 10 rpm; And / or, the porosity of the deposited second light absorbing layer is made 30-80% by making the angle between the normal direction of the sample stage and the normal direction of the evaporation source of the electron beam oblique deposition be 70-90° and rotating the sample stage at a speed of 0-10 rpm.

10. The preparation method according to claim 8, characterized in that, The method further comprises: using photolithography technology to form a preset pattern on the thermosensitive layer, the first light absorbing layer, and the second light absorbing layer.

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