Long-wave infrared detector and preparation method thereof

Abstract

The invention relates to the technical field of photoelectric detection, in particular to a long-wave infrared detector and a preparation method thereof. Comprising a plurality of detection pixels, each detection pixel comprises a strontium titanate block and a thermoelectric thin film layer, and each thermoelectric thin film layer is provided with a plurality of micropore structures in a rectangular array mode so as to detect infrared light in the wave band of 0.4-15 microns. The preparation method comprises the following steps: depositing a thermoelectric film on the surface of strontium titanate through a chemical vapor deposition method, forming a rectangular microporous structure pattern through photoetching after coating photoresist, forming pixels of rectangular microporous structures in array arrangement through argon ion beam etching, and preparing a metal electrode and an insulating layer on the pixels. According to the detector, due to the unique heterostructure, the detector has ultra-wideband infrared detection capacity, and self-driven high-sensitivity infrared detection can be achieved through the design of the micropore structure.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection technology, and in particular to a long-wave infrared detector and a preparation method thereof. Background Art

[0002] In the field of infrared detection technology, especially in the long-wave infrared region, the demand for high-performance detectors is growing. Long-wave infrared detectors are widely used in many fields such as military, security monitoring, environmental monitoring, and astronomical observation. However, existing long-wave infrared detectors have some limitations in material selection, structural design, and preparation process, which limit the further improvement of detector performance.

[0003] Traditional long-wave infrared detectors are limited by band gaps and a limited variety of materials, mainly based on thermoelectric materials such as bismuth telluride (Bi2Te3) and lead telluride (PbTe). Although these materials have certain thermoelectric properties, their Seebeck coefficients at room temperature are low, and their preparation processes are complex and costly.

[0004] The existing long-wave infrared detector preparation process often requires complex steps and high-cost equipment, such as molecular beam epitaxy (MBE), which limits the large-scale production and cost reduction of detectors. In order to improve the response speed and detection rate of detectors, innovations in detector structure design are needed. Traditional detector structures often have difficulty in achieving effective absorption and rapid response to infrared light. Summary of the invention

[0005] The present invention aims to at least improve one of the technical problems existing in the prior art. To this end, the present invention provides a long-wave infrared detector and a preparation method thereof.

[0006] According to the first aspect of the present invention, the long-wave infrared detector includes a plurality of detection pixels, each of which includes: Strontium titanate bulk; The thermoelectric film layer is located on the surface of the strontium titanate block. Each of the thermoelectric film layers is provided with a plurality of micro-hole structures in a rectangular array to detect infrared light in the 0.4 μm to 15 μm band. In a possible implementation of the first aspect, the thermoelectric film layer is rectangular, and the sum of the areas of the multiple microporous structures accounts for half of the total area of ​​the thermoelectric film layer. The microporous structure can increase the light absorption and at the same time form an asymmetric structure to increase the difference in response at the electrodes on both sides to increase the overall light response.

[0007] In a possible implementation manner of the first aspect, a distance between any two adjacent microporous structures is 5 μm to 15 μm, and the microporous structure is circular with a diameter of 10 μm.

[0008] In a possible implementation manner of the first aspect, a spacing between adjacent detection pixels is 2 μm to 800 μm to avoid signal crosstalk.

[0009] In a possible implementation of the first aspect, the type of the thermoelectric thin film layer includes at least one of bismuth telluride, lead telluride, lead telluride selenide, lead tin telluride, lead selenide (PbSe), lead selenide sulfur, and lead sulfide (PbS), which has excellent thermoelectric properties, and can perfectly epitaxially grow the thermoelectric thin film with good single crystal performance on the surface of a strontium titanate block.

[0010] A method for preparing a long-wave infrared detector according to an embodiment of the second aspect of the present invention, wherein the method for preparing the long-wave infrared detector as described above comprises the following steps: S1, depositing a thermoelectric thin film on the surface of the strontium titanate block to form a thermoelectric thin film layer; S2, after coating the thermoelectric thin film layer with photoresist, photolithography of a plurality of microporous structure patterns is performed to obtain a patterned thermoelectric thin film layer; S3, etching the patterned thermoelectric thin film layer to form detection pixels arranged in an array; S4, preparing a metal electrode and an insulating layer at the detection pixel; S5, obtaining the long-wave infrared detector.

[0011] In a possible implementation manner of the second aspect, the photolithography of the plurality of micro-hole structure patterns includes photolithography of a plurality of micro-hole structures arranged in a rectangular array.

[0012] In a possible implementation manner of the second aspect, the metal electrode is an interdigitated electrode, and the metal electrode includes a first electrode and a second electrode. The first electrode is connected to the detection pixel on the side containing the microporous structure; The second electrode is connected to the detection pixel on the side without the microporous structure, wherein an insulating layer is provided at the site where the paths of the first electrode and the second electrode cross and contact.

[0013] In a possible implementation of the second aspect, the insulating layer is prepared by an electron beam evaporation coating method, wherein the thickness of the insulating layer is 100 nm to 200 nm, so that the insulating layer has an insulating function without affecting the function of the second electrode.

[0014] In a possible implementation manner of the second aspect, the insulating layer material is at least one of silicon oxide, hafnium oxide, and titanium oxide.

[0015] According to the long-wave infrared detector of the present invention, a composite structure, namely a strontium titanate / thermoelectric material heterojunction, is designed, the substrate is strontium titanate, and the upper thermoelectric film layer utilizes the characteristics of low loss and subwavelength constraint in the long-wave infrared range of the bottom strontium titanate, that is, it has strong long-wave infrared absorption. When long-wave infrared light irradiates the heterojunction interface, strontium titanate will generate phonon polaritons at the interface to bind photons, preventing photons from diffusing to the surface of the material, and then generating a large number of phonons locally, which are conducted through the interface, causing the local temperature of the thermoelectric film layer to rise. Due to the thermoelectric effect, electron holes diffuse to the low temperature zone under the drive of the temperature field to form a voltage, thereby realizing long-wave infrared detection. In this way, the absorption and measurement of long-wave infrared can be separated, so that it can have ultra-wide-band infrared detection capabilities.

[0016] The multiple pixels in the long-wave infrared detector provided by the present invention are arranged in a two-dimensional grid shape, and the rectangular microporous structure can absorb infrared light with a wavelength of 0.4μm to 15μm, and output it in the form of an electrical signal. Due to the asymmetric structure of the thermoelectric film with a rectangular microporous structure, the absorption amount of the global light irradiated near the two electrodes is different, resulting in the inability to offset the generated photovoltage signal, and the conduction forms a unidirectional current. At the same time, the microporous structure can increase the light receiving area of ​​strontium titanate, thereby increasing the responsiveness.

[0017] The long-wave infrared detector provided by the present invention has an obvious response in the long-wave infrared spectral band and can realize self-driven focal plane photoelectric imaging. The present invention can work at room temperature, has an obvious response in the long-wave infrared spectral band, has a high detection rate and good responsiveness to infrared light in the 0.4μm to 15μm band, and has a self-driving function without the need for an external bias voltage.

[0018] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 is a schematic structural diagram of a long-wave infrared detector according to Embodiment 1 of the present invention; Figure 2 is a light microscope image of a long-wave infrared detector according to Example 1 of the present invention; Figure 3 is a schematic diagram of the Fourier infrared absorption spectrum of the long-wave infrared detector according to Example 1 of the present invention; Figure 4 is a schematic diagram of voltage results of micro-resolution photovoltage imaging of a long-wave infrared detector according to Example 1 of the present invention; Figure 5 is a photovoltage response diagram of a single detection pixel of the long-wave infrared detector according to Example 1 of the present invention; Figure 6 It is a flow chart of the preparation method of the long-wave infrared detector according to Example 2 of the present invention.

[0021] Reference numerals: A first electrode 1 , a second electrode 2 , a detection unit 3 , and an insulating layer 4 . DETAILED DESCRIPTION

[0022] The embodiments of the present invention are described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0023] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. 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 of the related listed items.

[0025] The terms "first", "second", "third", etc. in the specification and claims of the present application and the drawings are used to distinguish different objects rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a series of steps or units are included, or optionally, steps or units not listed are included, or optionally, other steps or units inherent to these processes, methods, products or devices are included.

[0026] Only the part relevant to the present application is shown in the accompanying drawings, but not all of the content. Before discussing the exemplary embodiments in more detail, it should be mentioned that some exemplary embodiments are described as processing or methods depicted as flow charts. Although the flow chart describes each operation (or step) as a sequential process, many of the operations therein can be implemented in parallel, concurrently or simultaneously. In addition, the order of each operation can be rearranged. When its operation is completed, the process can be terminated, but it can also have additional steps not included in the accompanying drawings. The process can correspond to a method, function, procedure, subroutine, subprogram, etc.

[0027] The terms "component", "module", "system", "unit", etc. used in this specification are used to represent computer-related entities, hardware, firmware, a combination of hardware and software, software, or software in execution. For example, a unit can be, but is not limited to, a process running on a processor, a processor, an object, an executable file, an execution thread, a program, and / or distributed between two or more computers. In addition, these units can be executed from various computer-readable media having various data structures stored thereon. Units can communicate through local and / or remote processes, for example, based on signals having one or more data packets (e.g., data from a second unit interacting with another unit in a local system, a distributed system, and / or a network. For example, the Internet interacts with other systems via signals).

[0028] Example 1 See also Figures 1 to 5 As shown, this embodiment provides a long-wave infrared detector, specifically a strontium titanate / thermoelectric material heterojunction long-wave infrared detector, which includes a plurality of detection pixels, each of which includes: Strontium titanate bulk; The thermoelectric film layer is located on the surface of the strontium titanate block. Each of the thermoelectric film layers is provided with a plurality of micro-hole structures in a rectangular array to detect infrared light in the 0.4 μm to 15 μm band. It should be noted that the thermoelectric film layer is rectangular, and the sum of the areas of the plurality of microporous structures accounts for half of the total area of ​​the thermoelectric film layer.

[0029] It should be noted that the detection pixel is rectangular, 400 μm long and 200 μm wide; the micropore structure is circular, with a diameter of 10 μm, and the spacing between any two adjacent micropore structures is 5 μm to 15 μm, preferably 10 μm in this embodiment; the spacing between adjacent pixels is 2 μm to 800 μm, preferably 200 μm in this embodiment.

[0030] It should be noted that the type of the thermoelectric thin film layer includes at least one of bismuth telluride, lead telluride, lead selenide, lead tin telluride, lead selenide, lead selenide sulfur, and lead sulfide.

[0031] Example 2 See also Figure 6 As shown, this embodiment provides a method for preparing a long-wave infrared detector, which is used to prepare a long-wave infrared detector, comprising the following steps: S1, depositing a thermoelectric thin film on the surface of the strontium titanate block by chemical vapor deposition to form a thermoelectric thin film layer; S2, after coating the thermoelectric thin film layer with photoresist, photolithography a plurality of microporous structure patterns to obtain a patterned thermoelectric thin film layer, wherein the microporous structure patterns are arranged in a rectangular array; S3, etching the patterned thermoelectric thin film layer by an argon ion beam to form detection pixels of an array-arranged rectangular micro-hole structure; S4, preparing a metal electrode and an insulating layer on the detection pixel of the rectangular microporous structure arranged in an array, wherein the metal electrode is an interdigitated electrode, and the metal electrode includes a first electrode and a second electrode, the first electrode is connected to the detection pixel on the side containing the microporous structure; the second electrode is connected to the detection pixel on the side without the microporous structure, and an insulating layer is provided at the site where the paths of the first electrode and the second electrode cross and contact; S5, obtaining the long-wave infrared detector.

[0032] It should be noted that the steps of chemical vapor deposition include: Along the flow direction of the carrier gas from upstream to downstream, the reaction sources are set to include PbS, PbSe, PbTe, Pb, S, Se or Sn, and multiple reaction sources ground in proportion. In this embodiment, the following examples of grinding the reaction sources in proportion are given, including PbS: S is 1:2; PbSe: Se is 1:2; PbTe: Sn is 1:1, the deposition position of the strontium titanate substrate is set, vacuum is drawn, the temperature is first increased, then the temperature is maintained, and finally the temperature is reduced to form a thermoelectric thin film layer.

[0033] It should be noted that the model of the equipment for coating the photoresist is (AZ5214E), and the coating is preferably carried out by a coating machine, and the coating speed is preferably 4000r / min. The thickness of the photoresist layer obtained by the coating is 1μm. After the coating is completed, the thermoelectric film layer of the coated photoresist is preferably heated and baked, and the baking is carried out on a heating platform. The baking temperature is preferably 100°C and the time is preferably 1min. The photolithography is preferably a maskless ultraviolet photolithography method, and the photolithography is preferably carried out using a maskless ultraviolet photolithography machine.

[0034] It should be noted that after photolithography, the pattern of the detection pixel 3 is 400 μm long and 200 μm wide; the micropore structure is circular with a diameter of 10 μm.

[0035] It should be noted that the number of detection pixels 3 is preferably 64, and the array is preferably 8×8.

[0036] It should be noted that after the patterned thermoelectric thin film layer is obtained, it is used as a substrate, and the photolithographic substrate is etched with argon ions using a capacitively coupled plasma etching (CCP) device (Haasrode® Avior® A), and the time is preferably 10 minutes. After the etching is completed, the substrate sample is taken out and immersed in an acetone solution, and the immersion time is preferably 10 minutes. Then, it is ultrasonicated with a high-frequency ultrasonic machine, and the ultrasonic temperature is preferably 50°C, the ultrasonic frequency is preferably 40kHz, and the ultrasonic time is preferably 2 minutes. Then, it is rinsed with deionized water and dried to obtain the detection pixel 3 of the rectangular microporous structure array.

[0037] It should be noted that the material of the metal electrode is preferably any one of Au, Ag, and Cu; the thickness of the single metal electrode is preferably 50 nm to 200 nm; the width is preferably 200 μm to 400 μm; and the length is preferably 100 μm to 200 μm.

[0038] It should be noted that the insulating layer is prepared by electron beam evaporation coating method, and the preparation environment of the insulating layer needs to meet the vacuum degree of preferably 10 -4 Pa, the width of the insulating layer is preferably 50 μm, the length is preferably 50 μm, and the thickness is preferably 100 nm to 200 nm; the material of the insulating layer is preferably any one of silicon oxide, hafnium oxide, and titanium oxide.

[0039] This embodiment provides a specific process for preparing a strontium titanate / lead selenide heterojunction long-wave infrared detector, which is as follows, including: (1) Growth of PbSe thin film. Along the flow direction of the carrier gas from upstream to downstream, 0.2 g of PbSe (purity of 99.9%) was taken as the evaporation source material and placed in the center of a horizontal tube furnace with a diameter of 12 inches. 0.4 g of selenium powder was placed in the front of the horizontal tube furnace as a supplementary source. A strontium titanate substrate with a (100) crystal plane was placed at the end of the horizontal tube furnace, which was 10 cm away from the outlet. After the horizontal tube furnace was sealed, a mechanical pump and a molecular pump were used to evacuate the furnace until the vacuum degree reached 1×10 -3Pa, and the flow rate of the carrier gas was controlled to be 30sccm (Standard Cubic Centimeter per Minute). The heating temperature of the selenium powder supplement source was controlled to be 300°C, the heating temperature of the PbSe powder was set to 750°C, and the temperature of the strontium titanate substrate was set to 450°C; the time for the tubular furnace to rise from room temperature to the heating temperature of the PbSe powder (750°C) was 75 minutes, and the steam formed by the reaction source and the selenium powder supplement source was transported to the surface of the strontium titanate substrate by the carrier gas for 5 minutes of reaction, and then the heating power of the tubular furnace was cut off, and the furnace body was naturally cooled to room temperature to obtain the PbSe film.

[0040] (2) Array preparation. A rectangular microporous structure array was fabricated using standard photolithography and argon ion etching technology. A 1-micron-thick photoresist (AZ5214E) was spin-coated on the PbSe film at a speed of 4000 r / min using a coater, and then baked on a heating table at 100°C for 1 minute. The desired microporous structure was photoetched using a maskless photolithography machine, and finally developed using a developer to obtain a photolithographic array substrate. A capacitively coupled plasma etching (CCP) device (Haasrode® Avior® A) was used to etch the photolithographic substrate with argon ions for 10 minutes. After etching, the sample was removed and immersed in an acetone solution for 10 minutes, and then ultrasonicated at 50°C and 40kHz for 2 minutes to obtain the target PbSe array, which was then rinsed and dried with deionized water to obtain a PbSe array.

[0041] (3) Preparation of electrodes. The specific preparation method is to perform three overlays on the rectangular microporous structure of the obtained detection pixel 3, and use electron beam evaporation coating equipment to batch-deposit the second electrode 2, the insulating layer 4 and the first electrode 1, wherein the second electrode 2 is used as the lower electrode and is prepared by Au single substance, and each single strip of the lower electrode has a thickness of 100nm, a width of 200μm and a length of 100μm; the material of the insulating layer 4 is HfO2, and the first electrode 1 is used as the upper electrode and is prepared by Au single substance, and each single strip of the upper electrode has a thickness of 100nm, a width of 200μm and a length of 100μm.

[0042] See also Figure 2 As shown, it is a light microscope image of the detection pixel obtained by the preparation method. Figure 2 It can be seen that the array shape of each detection pixel in the light microscope image is extremely regular.

[0043] See also Figure 3 As shown in FIG. 1 , it is a schematic diagram of the Fourier infrared absorption spectrum of strontium titanate with a (100) crystal plane in this embodiment. The results in the figure show that it has an extremely large absorption rate for long-wave infrared.

[0044] See also Figure 4As shown in FIG. 1 , the voltage result of the micro-resolution photovoltage imaging of the strontium titanate / PbSe heterojunction prepared in the embodiment of the present invention is shown. The scale bar in the figure is 40 μm. Figure 4 (a) is the reflected photocurrent imaging diagram, such as Figure 4 (b) is a picture of the device of strontium titanate / PbSe heterojunction scanned by a laser with a wavelength of 4 μm. Figure 4 (c) is a picture of a 10μm laser scanning a strontium titanate / PbSe heterojunction device. It can be seen that the 4μm laser response is widely distributed in the PbSe film and electrode, and the 10μm response is widely distributed in the strontium titanate substrate, indicating that the 10μm laser response comes from the strontium titanate substrate.

[0045] See also Figure 5 As shown in FIG. 1 , a single detection pixel photovoltage response diagram of a long-wave infrared detector of a strontium titanate / PbSe heterojunction prepared in an embodiment of the present invention is shown. Figure 5 (a) is the light response diagram of light with a wavelength of 10 μm corresponding to different optical powers, such as Figure 5 (b) is a graph showing the responsivity and specific detection rate of 10 μm light at different optical powers, where the left axis represents the responsivity and the right axis represents the specific detection rate. Under the condition of 10 μm wavelength light, the long-wave infrared detector shows a very obvious light response signal, and the specific detection rate reaches 10 at room temperature. 8 It has a strong long-wave infrared response.

[0046] According to the long-wave infrared detector of the present invention, a composite structure, namely a strontium titanate / thermoelectric material heterojunction, is designed, the substrate is strontium titanate, and the upper thermoelectric film layer utilizes the characteristics of low loss and subwavelength constraint in the long-wave infrared range of the bottom strontium titanate, that is, it has strong long-wave infrared absorption. When long-wave infrared light irradiates the heterojunction interface, strontium titanate will generate phonon polaritons at the interface to bind photons, preventing photons from diffusing to the surface of the material, and then generating a large number of phonons locally, which are conducted through the interface, causing the local temperature of the thermoelectric film layer to rise. Due to the thermoelectric effect, electron holes diffuse to the low temperature zone under the drive of the temperature field to form a voltage, thereby realizing long-wave infrared detection. In this way, the absorption and measurement of long-wave infrared can be separated, so that it can have ultra-wide-band infrared detection capabilities.

[0047] The multiple pixels in the long-wave infrared detector provided by the present invention are arranged in a two-dimensional grid shape, and the rectangular microporous structure can absorb infrared light with a wavelength of 0.4μm to 15μm, and output it in the form of an electrical signal. Due to the asymmetric structure of the thermoelectric film with a rectangular microporous structure, the absorption amount of the global light irradiated near the two electrodes is different, resulting in the inability to offset the generated photovoltage signal, and the conduction forms a unidirectional current. At the same time, the microporous structure can increase the light receiving area of ​​strontium titanate, thereby increasing the responsiveness.

[0048] The long-wave infrared detector provided by the present invention has an obvious response in the long-wave infrared spectral band and can realize self-driven focal plane photoelectric imaging. The present invention can work at room temperature, has an obvious response in the long-wave infrared spectral band, has a high detection rate and good responsiveness to infrared light in the 0.4μm to 15μm band, and has a self-driving function without the need for an external bias voltage.

[0049] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the invention.

[0050] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example.

[0051] Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Mentioning "embodiment" in this article means that the specific features, structures or characteristics described in conjunction with the embodiment may be included in at least one embodiment of the present embodiment application. The appearance of this phrase in various positions in the specification is not necessarily the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It can be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0052] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A long-wave infrared detector, characterized in that: It includes a plurality of detection pixels, each of which includes: Strontium titanate bulk; The thermoelectric film layer is located on the surface of the strontium titanate block. Each of the thermoelectric film layers is provided with a plurality of micro-hole structures in a rectangular array to detect infrared light in the 0.4 μm to 15 μm band.

2. The long-wave infrared detector according to claim 1, characterized in that: The thermoelectric film layer is rectangular in shape, and the sum of the areas of the plurality of microporous structures accounts for half of the total area of ​​the thermoelectric film layer.

3. The long-wave infrared detector according to claim 1, characterized in that: The distance between any two adjacent microporous structures is 5 μm to 15 μm, and the microporous structure is circular with a diameter of 10 μm.

4. The long-wave infrared detector according to claim 1, characterized in that: The spacing between adjacent detection pixels is 2μm to 800μm.

5. The long-wave infrared detector according to claim 1, characterized in that: The type of the thermoelectric thin film layer includes at least one of bismuth telluride, lead telluride, lead selenide, lead tin telluride, lead selenide, lead selenide sulfur, and lead sulfide.

6. A method for preparing a long-wave infrared detector, characterized in that: The method for preparing the long-wave infrared detector according to any one of claims 1 to 5 comprises the following steps: S1, depositing a thermoelectric thin film on the surface of the strontium titanate block to form a thermoelectric thin film layer; S2, after coating the thermoelectric thin film layer with photoresist, photolithography of a plurality of microporous structure patterns is performed to obtain a patterned thermoelectric thin film layer; S3, etching the patterned thermoelectric thin film layer to form detection pixels arranged in an array; S4, preparing a metal electrode and an insulating layer at the detection pixel; S5, obtaining the long-wave infrared detector.

7. The method for preparing a long-wave infrared detector according to claim 6, characterized in that: The photolithography of the plurality of micro-hole structure patterns includes photolithography of a plurality of micro-hole structures arranged in a rectangular array.

8. The method for preparing a long-wave infrared detector according to claim 6, characterized in that: The metal electrode is an interdigitated electrode, and the metal electrode includes a first electrode and a second electrode. The first electrode is connected to the detection pixel on the side containing the microporous structure; The second electrode is connected to the detection pixel on the side without the microporous structure, wherein an insulating layer is provided at the site where the paths of the first electrode and the second electrode cross and contact.

9. The method for preparing a long-wave infrared detector according to claim 6, characterized in that: The insulating layer is prepared by an electron beam evaporation coating method, wherein the thickness of the insulating layer is 100nm-200nm.

10. The method for preparing a long-wave infrared detector according to claim 9, characterized in that: The insulating layer material is at least one of silicon oxide, hafnium oxide and titanium oxide.

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