Perovskite infrared detector structure and preparation method therefor, and infrared imaging chip

Abstract

Provided in the present application are a perovskite infrared detector structure and a preparation method therefor, and an infrared imaging chip. The detector structure comprises: a substrate; a P-type semiconductor layer, which is arranged on the substrate; an aluminum oxide layer, which is arranged on the P-type semiconductor layer; a photosensitive perovskite layer, which is arranged on the aluminum oxide layer; an N-type semiconductor layer, which is arranged on the photosensitive perovskite layer; a buffer layer, which is arranged on the N-type semiconductor layer; and a back electrode, which is arranged on the buffer layer, wherein the photosensitive perovskite layer is made of FA0.7MA0.3Pb0.5Sn0.5I3, with an optical bandgap<1.26 eV. The entire detector structure is fabricated by using a specific preparation process, and thus a perovskite thin film having favorable subsurface morphology, a lower detect-state density and high quality can be obtained. Therefore, the device achieves good performance such as high detectivity, fast response speed, wide spectral response range, good process compatibility and high imaging quality, and is suitable for the technical fields of semiconductor photoelectric materials and devices.

Description

A perovskite infrared detector structure, its fabrication method, and an infrared imaging chip. Technical Field

[0001] This application relates to the field of semiconductor optoelectronic materials and devices, and in particular to a perovskite infrared detector structure, its fabrication method, and an infrared imaging chip. Background Technology

[0002] Photodetectors convert optical signals into measurable electrical signals, serving as crucial connection points between different devices and forming the foundation of modern industrial interconnection and artificial intelligence. Infrared radiation has wide applications in fields such as life and health, national defense and security, autonomous driving, optical imaging, and optical communication. Therefore, infrared photodetectors are of great significance in both military and civilian fields.

[0003] Commercial infrared photodetectors typically use inorganic non-metallic materials such as silicon, germanium, and indium gallium arsenide as photosensitive materials. The crystal growth of these materials requires extremely harsh high-temperature and high-vacuum environments, leading to high energy consumption and high manufacturing costs. In contrast, metal halide perovskites offer superior photoelectric properties and a high light absorption coefficient (≈10). 5 cm -1 Its adjustable optical bandgap (1.2–3.0 eV), low fabrication cost, rapid solution processing, extremely high defect tolerance and low defect state density, high carrier mobility, long carrier lifetime and diffusion length have led to its widespread application in the fabrication of infrared photodetectors.

[0004] With the rapid development of perovskite infrared detectors, the demand for infrared detectors in various fields is also increasing, including but not limited to high detection sensitivity, fast response speed, and wide detection range. However, existing perovskite infrared detectors still suffer from problems such as low sensitivity to infrared radiation, slow response speed, and difficulty in compatibility with heterogeneous readout circuit chips, making it difficult to meet market demands. Summary of the Invention

[0005] To address one of the aforementioned technical deficiencies, this application provides a perovskite infrared detector structure, its fabrication method, and an infrared imaging chip.

[0006] According to a first aspect of this application, a perovskite infrared detector structure is provided, comprising: a substrate; a P-type semiconductor layer disposed on the substrate; an alumina layer disposed on the P-type semiconductor layer; a photosensitive perovskite layer disposed on the alumina layer; an N-type semiconductor layer disposed on the photosensitive perovskite layer; a buffer layer disposed on the N-type semiconductor layer; and a back electrode disposed on the buffer layer.

[0007] Preferably, the photosensitive perovskite layer is prepared from a narrow bandgap metal halide FA.0.7 MA 0.3 Pb 0.5 Sn 0.5 I3 has an optical band gap of <1.26 eV.

[0008] Preferably, the substrate is made of indium-doped tin oxide; the P-type semiconductor layer is made of [6-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid; the N-type semiconductor layer is made of fullerene; the buffer layer is made of copper bath ether; and the back electrode is made of silver.

[0009] Preferably, the thickness of the P-type semiconductor layer is 10–20 nm; the thickness of the alumina layer is 20–30 nm; the thickness of the photosensitive perovskite layer is 400–500 nm; the thickness of the N-type semiconductor layer is 25–30 nm; the thickness of the buffer layer is 5–7 nm; and the thickness of the back electrode is 80–120 nm.

[0010] More preferably, the thickness of the P-type semiconductor layer is 15 nm; the thickness of the alumina layer is 30 nm; the thickness of the photosensitive perovskite layer is 440 nm; the thickness of the N-type semiconductor layer is 28 nm; the thickness of the buffer layer is 6 nm; and the thickness of the back electrode is 100 nm.

[0011] According to a second aspect of this application, a method for fabricating a perovskite infrared detector structure as described above is provided, comprising: S10, providing a substrate; S20, processing a P-type semiconductor material using a spin-coating process to form a P-type semiconductor layer on the substrate; S30, processing a nano-alumina material using a spin-coating process to form an alumina layer on the P-type semiconductor layer; S40, processing a perovskite precursor material using a spin-coating process to form a photosensitive perovskite layer on the alumina layer; S50, processing an N-type semiconductor material using a vacuum evaporation process to form an N-type semiconductor layer on the photosensitive perovskite layer; S60, forming a buffer layer on the N-type semiconductor layer using a vacuum evaporation process; and S70, processing a conductive material using a vacuum evaporation process to form a back electrode on the buffer layer.

[0012] Preferably, step S40 specifically includes: weighing appropriate amounts of formamidine iodoformide, methyl iodoformide, lead iodide, and stannous iodide; then adding a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio ranging from 3:1 to 5:1, and stirring at room temperature until completely dissolved to obtain FA. 0.7 MA 0.3 Pb 0.5 Sn 0.5I. Perovskite precursor solution; spin-coating the perovskite precursor solution onto an alumina layer, and adding chlorobenzene anti-solvent dropwise during the spin-coating process; after spin-coating, annealing is performed to obtain a perovskite film, forming a photosensitive perovskite layer.

[0013] More preferably, in step S40: the molar ratio of formamidine iodomethylamine, methyl iodide, lead iodide, and stannous iodide is 7:3:5:5; the volume ratio of the mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide is 4:1; and the obtained FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 The concentration of the I3 perovskite precursor solution was 1.1 mol / L. When spin-coating the perovskite precursor solution, the volume of the perovskite precursor solution was 120 μL, the spin coater speed was 6000 rpm, the acceleration was 3000 rpm, and the time was 60 seconds. At the 45th second of spin coating, 350 μL of chlorobenzene antisolvent was added dropwise. After spin coating was completed, the film was annealed at 100℃ for 10 minutes to obtain a perovskite film with a thickness of 440 nm, forming a photosensitive perovskite layer.

[0014] More preferably, step S10 specifically includes: providing a substrate and performing the following cleaning treatment on the substrate: first ultrasonically cleaning with a cleaning agent for 20 minutes, then ultrasonically cleaning with deionized water, anhydrous ethanol, acetone and isopropanol for 20 minutes respectively, then drying for 30 minutes, and finally cleaning the surface again with nitrogen gas, and then treating with ozone for 20 minutes before use.

[0015] Step S20 specifically includes: first, dissolving [6-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid in ethanol to form a solution with a concentration of 2 mg / mL; then, spin-coating 120 μL of the solution onto the cleaned substrate 10, wherein: the spin coater speed is 6000 rpm, the acceleration is 3000 rpm, and the time is 30 seconds; after spin-coating, annealing is performed at 100°C for 10 minutes to obtain a P-type semiconductor layer with a thickness of 15 nm;

[0016] Step S30 specifically includes: first, diluting the nano-alumina solution in isopropanol at a volume ratio of 1:20, and then spin-coating 150 μL of the diluted solution onto the P-type semiconductor layer 20, wherein: the spin coater speed is 6000 rpm, the acceleration is 3000 rpm, and the time is 30 seconds; after spin-coating, annealing is performed at 120℃ for 20 minutes to obtain an alumina layer with a thickness of 30 nm;

[0017] Step S50 specifically includes: depositing fullerene material on a photosensitive perovskite layer using a vacuum evaporation process to obtain an N-type semiconductor layer with a thickness of 28 nm, wherein: the evaporation rate is...

[0018] Step S60 specifically includes: depositing copper bath material on an N-type semiconductor layer using a vacuum evaporation process to obtain a buffer layer with a thickness of 6 nm, wherein: the evaporation rate is...

[0019] Step S70 specifically includes: after placing the device into the vacuum coating machine, first reducing the internal air pressure of the machine to 5×10. -4 Pa, then begin preparing the metallic silver electrode; when the thickness of the silver electrode is between 0 and 5 nm, control the evaporation rate to [value missing]. Subsequently, the evaporation rate increases for every 5nm increase in thickness. Ultimately, the evaporation rate will be maintained at Until the vapor deposition is complete.

[0020] According to a third aspect of this application, an infrared imaging chip is provided, comprising:

[0021] Photodetector: An array structure formed by the aforementioned perovskite infrared detector structure, which is fabricated using an ultrafast laser etching process, and is used to convert the received infrared radiation signal into a readable current signal.

[0022] TFT readout circuit: Electrically connected to the photodetector, used to read the current signal output by the photodetector, form a corresponding pattern based on the reading result, and perform image output.

[0023] The perovskite infrared detector structure provided in this application, due to its special structure, special composition of perovskite photosensitive material, and special fabrication process, has the following advantages compared with traditional perovskite infrared detectors:

[0024] 1. The structure of P-type semiconductor layer + alumina layer + photosensitive perovskite layer + N-type semiconductor layer + buffer layer + back electrode in this application enables infrared radiation to be absorbed by the photosensitive perovskite layer, generating electron-hole pairs. Electrons are excited to the conduction band, leaving holes in the valence band. Then, electrons are extracted by the N-type semiconductor layer and transported to the back electrode, while holes are extracted by the P-type semiconductor layer, flow through the substrate to the back electrode, and recombine with electrons. The directional flow of charge carriers (electrons and holes) forms a current, thereby realizing the conversion of optical radiation signals into measurable current signals. In particular, the nano-alumina layer introduced between the P-type semiconductor layer and the photosensitive perovskite layer improves the wettability and interfacial contact of the photosensitive perovskite layer, thereby improving the weak light detection capability and response speed of the entire device to a certain extent.

[0025] 2. The photosensitive perovskite layer in this application has a specific composition. The synergistic effect of lead (Pb) and tin (Sn) helps optimize the optical bandgap, spectral response characteristics, and charge transport performance of the material. Lead provides good electron transport capability, while tin helps reduce the bandgap and improve the conductivity of the material, thereby achieving efficient charge separation and transport in infrared detectors. In addition, tin reduces the bandgap of the perovskite material and enhances the material's absorption of infrared radiation, thereby broadening the spectral response range. This allows the entire perovskite material to effectively absorb a wide range of spectra, including visible and infrared light. The mixed cation structure of FA and MA helps optimize the structural stability and electronic properties of the perovskite crystal. The combination of the two can improve the crystal quality of the perovskite film and reduce defects, thereby improving the detector's response speed and detection sensitivity.

[0026] 3. Fabrication process in this application: Optimal molar ratio of raw materials is used to prepare perovskite thin films, resulting in narrow optical band gaps and broadening the spectral response range of the device. The ratio of DMF to DMSO in the precursor solution is strictly controlled, forming lattice-stable crystals. An anti-solvent-assisted spin-coating method is employed, which not only rapidly removes excess polar solvent molecules from the precursor film, forming a stable intermediate film, but also offers advantages such as simple process and ease of adjustment. Multiple steps utilize vapor deposition for thin film preparation, resulting in high controllability and repeatability, and low cost for large-scale production. Precise laser etching is used for array structure fabrication, providing excellent imaging capabilities. Furthermore, the process is simple, portable, and highly scalable, enabling larger arrays and higher resolution imaging. All process steps are compatible with readout circuitry, resulting in lower manufacturing costs, enabling large-scale production, and compatibility with CMOS and TFT chips for integrated imaging applications with TFT chips.

[0027] Using the fabrication process described in this application, perovskite thin films with good surface morphology, low defect state density, and good quality, as well as other high-quality thin film layers, can be prepared. This results in the formation of a detector with excellent performance such as high detectivity, fast response speed, wide spectral response range, good process compatibility, and high imaging quality, which are effects that many existing perovskite infrared detectors cannot achieve.

[0028] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of what is pointed out in the written description and the accompanying drawings. Attached Figure Description

[0029] The accompanying drawings described herein are used to provide a further understanding of the present application and form a part of the present application. The schematic embodiments and descriptions thereof are used to explain the present application and do not unduly limit the present application. In the drawings:

[0030] FIG. 1 is a schematic structural diagram of a perovskite infrared detector array provided by the present application;

[0031] FIG. 2 is a scanning electron microscope (SEM) image of a perovskite thin film prepared by the preparation method provided by the present application;

[0032] FIG. 3 is a curve showing the variation of the external quantum efficiency of a perovskite infrared detector prepared by the preparation method provided by the present application with the irradiation wavelength;

[0033] FIG. 4 is a curve showing the variation of the responsivity of a perovskite infrared detector prepared by the preparation method provided by the present application with the irradiation wavelength;

[0034] FIG. 5 is the response time of a perovskite infrared detector prepared by the preparation method provided by the present application;

[0035] FIG. 6 is a curve showing the variation of the specific detectivity of a perovskite infrared detector prepared by the preparation method provided by the present application with the irradiation wavelength;

[0036] FIG. 7 is an imaging result diagram of the letter "S" by a 5×5 infrared detector array provided by the present application under 980 nm light illumination;

[0037] FIG. 8 is an imaging result diagram of the Chinese character "Shanda" by a 64×64 infrared imaging chip based on a TFT readout circuit provided by the present application under 980 nm infrared radiation illumination;

[0038] In the figure: 10 is a substrate, 20 is a P-type semiconductor layer, 30 is an alumina layer, 40 is a photosensitive perovskite layer, 50 is an N-type semiconductor layer, 60 is a buffer layer, and 70 is a back electrode. Detailed Embodiments

[0039] In order to make the technical solutions and advantages in the embodiments of the present application clearer and more understandable, the following further details the exemplary embodiments of the present application with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application and not an exhaustive list of all embodiments. It should be noted that, without conflict, the embodiments and features in the embodiments of the present application can be combined with each other.

[0040] Regarding some problems existing in the prior art:

[0041] In a first aspect, an embodiment of the present application provides a perovskite infrared detector structure.

[0042] For example, as shown in FIG1, the perovskite infrared detector structure includes:

[0043] Substrate 10: Used for transporting charge carriers and transmitting infrared radiation;

[0044] P-type semiconductor layer 20: disposed on the substrate 10: used for extracting and conducting holes;

[0045] Alumina layer 30: disposed on P-type semiconductor layer 20: used to improve the wettability of perovskite solution on P-type semiconductor surface and suppress dark current of device;

[0046] Photosensitive perovskite layer 40: disposed on alumina layer 30: used to capture infrared radiation photons;

[0047] N-type semiconductor layer 50: disposed on photosensitive perovskite layer 40: used for extracting and conducting electrons;

[0048] Buffer layer 60: disposed on N-type semiconductor layer 50: used for carrier tunneling;

[0049] Back electrode 70: disposed on buffer layer 60: used for transporting charge carriers.

[0050] The infrared detector in this embodiment operates based on the photovoltaic effect. During operation, infrared radiation photons with energy not less than the perovskite bandgap are captured and absorbed by the photosensitive perovskite layer, generating electron-hole pairs. Electrons are excited to the bottom of the conduction band, leaving holes in the valence band. Electrons are then extracted by the N-type semiconductor layer 50 and transported to the back electrode 70, while holes are extracted by the P-type semiconductor layer 20, flow through the substrate 10 to the back electrode 70, and recombine with electrons. This directional flow of charge carriers (electrons and holes) forms a current, thereby converting the optical radiation signal into a measurable current signal, ultimately achieving photoelectric conversion. The nano-alumina layer 30 introduced between the P-type semiconductor layer 20 and the photosensitive perovskite layer 40 improves the wettability and interfacial contact of the photosensitive perovskite layer 40, thus enhancing the weak light detection capability and response speed of the entire device to a certain extent.

[0051] Among some possible ways to implement the first aspect:

[0052] The substrate 10 is made of a conductive oxide, which may be fluorine-doped tin oxide (FTO), indium-doped tin oxide (ITO), or indium gallium zinc oxide (IGZO). In this embodiment, indium-doped tin oxide (ITO) is preferred.

[0053] The P-type semiconductor layer 20 is made of nickel oxide (NiO). xThe semiconductor is a doped semiconductor of one or more of the following: poly(4-phenyl)(2,4,6-trimethylphenyl)amine (PTAA), p-type assembled monomolecule [2-(3,6-dimethoxy-9H-carbazole-9-yl)ethyl]phosphonic acid (MeO-2PACZ), p-type assembled monomolecule [4-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-4PACZ), and p-type assembled monomolecule [6-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-6PACZ). In the embodiments of this application, [6-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-6PACZ) is preferred.

[0054] The photosensitive perovskite layer 40 is made of narrow bandgap metal halide perovskite, and the bandgap is adjusted by ion doping. The specific chemical formula of the material is APb. 1-x Sn x X3; where: 0≤x≤1, A is a +1 valent cation (such as methylamine (MA), formamidinium (FA), cesium (Cs), rubidium (Rb) ions and their mixtures), and X is a -1 valent halide ion (such as fluorine (F), chloride (Cl), bromine (Br), iodine (I) or their mixtures); in the embodiments of this application, FA is preferred. 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3 has an optical bandgap of <1.26 eV. Generally, the optical bandgap characteristics of narrow bandgap metal halides are usually less than 1.58 eV, while the optical bandgap of the photosensitive perovskite layer 40 material in this application is less than 1.26 eV, which can be said to be a major breakthrough.

[0055] The material used to prepare the N-type semiconductor layer 50 can be fullerene (C 60 ), or [6,6]-phenyl-C61-butyrate methyl ester (PCBM), or tin dioxide (SnO2), and in the embodiments of this application, fullerene (C 60 );

[0056] The buffer layer 60 is made of copper bath (BCP);

[0057] The back electrode 70 can be made of gold (Au), silver (Ag), copper (Cu), or indium-doped tin oxide (ITO). Since silver electrode is a low-cost electrode that is easy to deposit and has excellent conductivity, silver (Ag) is preferred in this embodiment.

[0058] The photosensitive perovskite layer 40 in this embodiment has a specific composition. The synergistic effect of lead (Pb) and tin (Sn) helps optimize the optical bandgap, spectral response characteristics, and charge transport performance of the material. Lead provides good electron transport capability, while tin helps reduce the bandgap and improve the conductivity of the material, thereby achieving efficient charge separation and transport in the infrared detector. In addition, tin reduces the bandgap of the perovskite material and enhances the material's absorption of infrared radiation, thereby broadening the spectral response range. This allows the entire perovskite material to effectively absorb a wide range of spectra, including visible and infrared light. The mixed cation structure of FA and MA helps optimize the structural stability and electronic properties of the perovskite crystal. The combination of the two can improve the crystal quality of the perovskite film and reduce defects, thereby improving the detector's response speed and detection sensitivity.

[0059] Among some possible ways to implement the first aspect:

[0060] The thickness of the P-type semiconductor layer 20 ranges from 10 to 20 nm, and is preferably 15 nm in this embodiment.

[0061] The thickness of the alumina layer 30 ranges from 20 to 30 nm, and is preferably 30 nm in this embodiment.

[0062] The thickness of the photosensitive perovskite layer 40 ranges from 400 to 500 nm, and is preferably 440 nm in this embodiment.

[0063] The thickness of the N-type semiconductor layer 50 ranges from 25 to 30 nm, and is preferably 28 nm in this embodiment.

[0064] The thickness of the buffer layer 60 ranges from 5 to 7 nm, and is preferably 6 nm in this embodiment.

[0065] The thickness of the back electrode 70 ranges from 80 to 120 nm, and is preferably 100 nm in this embodiment.

[0066] Secondly, this application provides a method for preparing the above-mentioned perovskite infrared detector structure.

[0067] For example, the preparation method includes:

[0068] S10, providing substrate 10;

[0069] S20. The P-type semiconductor material is processed by spin coating process to form a P-type semiconductor layer 20 on the substrate 10;

[0070] S30. The nano-alumina material is processed by spin coating to form an alumina layer 30 on the P-type semiconductor layer 20.

[0071] S40. The perovskite precursor material is processed by spin coating to form a photosensitive perovskite layer 40 on the alumina layer 30.

[0072] S50. The N-type semiconductor material is processed by vacuum evaporation to form an N-type semiconductor layer 50 on the photosensitive perovskite layer 40.

[0073] S60. A buffer layer 60 is formed on the N-type semiconductor layer 50 using a vacuum evaporation process.

[0074] S70. The conductive material is treated by vacuum evaporation process to form the back electrode 70 on the buffer layer 60.

[0075] Among some possible ways to implement the second aspect:

[0076] Step S10 specifically includes: providing a substrate 10 and performing the following cleaning treatment on the substrate 10: first, ultrasonically cleaning with a cleaning agent for 20 minutes to remove grease and organic matter from the surface of the substrate 10, wherein: the cleaning agent is mainly composed of tap water and glass water, with a volume ratio of 1:3; then, ultrasonically cleaning with deionized water, anhydrous ethanol, acetone and isopropanol for 20 minutes each in sequence, then drying for 30 minutes, and finally cleaning the surface again with nitrogen gas, and then treating with ozone for 20 minutes before use;

[0077] Step S20 specifically includes: first, dissolving [6-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid in ethanol to form a solution with a concentration of 2 mg / mL; then, spin-coating 120 μL of the solution onto the cleaned substrate 10, wherein: the spin coater speed is 6000 rpm, the acceleration is 3000 rpm, and the time is 30 seconds; after spin-coating, annealing is performed at 100°C for 10 minutes to obtain a P-type semiconductor layer 20 with a thickness of 15 nm;

[0078] Step S30 specifically includes: first, diluting the nano-alumina solution in isopropanol at a volume ratio of 1:20, and then spin-coating 150 μL of the diluted solution onto the P-type semiconductor layer 20, wherein: the spin coater speed is 6000 rpm, the acceleration is 3000 rpm, and the time is 30 seconds; after spin-coating, annealing is performed at 120℃ for 20 minutes to obtain an alumina layer 30 with a thickness of 30 nm;

[0079] Step S40 specifically includes: weighing out powdered raw materials of formamidine iodide (FAI), methylamine iodide (MAI), lead iodide (PbI2), and stannous iodide (SnI2) in a molar ratio of 7:3:5:5; after extensive experimental verification, this ratio can achieve perovskite thin films with narrow optical band gaps, thus broadening the spectral response range of infrared detectors; then adding a mixed solvent of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) in a volume ratio ranging from 3:1 to 5:1, and stirring at room temperature for 2 hours until completely dissolved to obtain FAI with a concentration ranging from 0.9 to 1.3 mol / L. 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3 perovskite precursor solution; In the embodiments of this application: the volume ratio of DMF to DMSO is preferably 4:1. Extensive experimental verification has shown that this volume ratio promotes the formation of lattice-stable crystals and dense perovskite films, enabling the detector to achieve the lowest possible dark current; the resulting FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 The preferred concentration of the I3 perovskite precursor solution is 1.1 mol / L. Extensive experimental verification shows that at this concentration, the perovskite film thickness is approximately 440 nm, achieving the optimal transit length and time for charge carriers and resulting in the fastest detector response speed. 120 μL of the perovskite precursor solution is spin-coated onto the alumina layer 30, with a spin coater speed of 6000 rpm, an acceleration of 3000 rpm, and a spin coat time of 60 seconds. At the 45-second mark of spin coat, 350 μL of chlorobenzene anti-solvent is added. Extensive experimental verification shows that this process step can form a stable intermediate film, rapidly removing excess polar solvent molecules from the precursor film and obtaining a smooth and flat perovskite film. After spin coat, the film is annealed at 100°C for 10 minutes to obtain a perovskite film with a thickness of 440 nm, forming the photosensitive perovskite layer 40.

[0080] Step S50 specifically includes: depositing fullerene (C) on the photosensitive perovskite layer 40 using a vacuum evaporation process. 60 The material was used to obtain an N-type semiconductor layer 50 with a thickness of 28 nm, wherein the evaporation rate ranged from [value missing]. The preferred embodiments in this application are... At this evaporation rate, C can be guaranteed. 60 The materials will not experience burst steaming.

[0081] Step S60 specifically includes: depositing bath copper ether (BCP) material on the N-type semiconductor layer 50 using a vacuum evaporation process to obtain a buffer layer 60 with a thickness of 6 nm, wherein: the evaporation rate range is... The preferred embodiments in this application are... This steaming rate ensures that the BCP material will not experience burst steaming.

[0082] Step S70 specifically includes: placing the device, after completing the aforementioned process steps, face down into the vacuum coating machine, and first reducing the internal air pressure of the machine to 5×10. -4 Pa, then begin preparing the metallic silver electrode; when the thickness of the silver electrode is between 0 and 5 nm, control the evaporation rate to [value missing]. Subsequently, the evaporation rate increases for every 5nm increase in thickness. Ultimately, the evaporation rate will be maintained at This process continues until the vapor deposition is complete. This step prevents the device surface from overheating due to excessively fast vapor deposition, which could affect device performance. It should be noted that after vapor deposition is completed, the device can only be removed after the machine has returned to standard atmospheric pressure and cooled down.

[0083] The fabrication process in this application employs an optimal molar ratio of raw materials to prepare the perovskite thin film, resulting in a narrow optical bandgap and broadening the spectral response range of the device. Strict control of the ratio of DMF to DMSO in the precursor solution ensures the formation of a lattice-stable crystal. The use of an anti-solvent-assisted spin-coating method not only rapidly removes excess polar solvent molecules from the precursor film, forming a stable intermediate film, but also offers advantages such as process simplicity and ease of adjustment. Multiple steps utilize vapor deposition for thin film preparation, resulting in high controllability and repeatability, and low cost for large-scale production. Using the fabrication process in this application, perovskite thin films with good surface morphology, low defect state density, and high quality, as well as other high-quality thin film layers, can be prepared. This results in a detector with superior performance, including high detectivity, fast response speed, wide spectral response range, good process compatibility, and high imaging quality—effects far exceeding those of many existing perovskite infrared detectors.

[0084] Thirdly, this application provides an infrared imaging chip in its embodiments.

[0085] For example, the infrared imaging chip includes:

[0086] Photodetector: An array structure formed by the above-mentioned perovskite infrared detector structure, which is fabricated using an ultrafast laser etching process, and is used to convert the received infrared radiation signal into a readable current signal.

[0087] TFT readout circuit: Electrically connected to the photodetector, used to read the current signal output by the photodetector, form a corresponding pattern based on the reading result, and perform image output.

[0088] Among some possible ways to implement the third aspect:

[0089] The equipment used to fabricate the array structure is a nanosecond pulsed laser with a wavelength of 355nm and a power of 3W.

[0090] The fabrication process in this application uses a precise laser etching method to create the array structure, which has excellent imaging capabilities. Moreover, the process is simple, portable, and has good scalability, enabling imaging with larger array sizes and higher resolutions. All process steps are compatible with readout circuitry, resulting in lower manufacturing costs and the ability to mass-produce. Furthermore, it is compatible with CMOS and TFT chips, enabling integrated imaging applications with TFT chips.

[0091] In this embodiment of the application, after repeated exploration and verification, the optimal perovskite infrared detector structure prepared by the aforementioned method has the following structural parameters and process parameters:

[0092] Substrate 10 is made of indium-doped tin oxide (ITO).

[0093] P-type semiconductor layer 20: The material is [6-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid (MeO-6PACZ), with a thickness of 15nm;

[0094] Alumina layer 30: The material is nano-alumina (Al2O3), with a thickness of 30nm;

[0095] Photosensitive perovskite layer 40: material is FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3, with a thickness of 440 nm; during preparation: the molar ratio of formamidine iodoformide (FAI), methyl iodoformide (MAI), lead iodide (PbI2), and stannous iodide (SnI2) powder raw materials was 7:3:5:5, and the volume ratio of N,N-dimethylformamide (DMF) and dimethyl sulfoxide (DMSO) was 4:1, resulting in FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 The concentration of the I3 perovskite precursor solution was 1.1 mol / L. During the spin coating of the precursor solution, 350 μL of chlorobenzene antisolvent was added dropwise at the 45th second of spin coating.

[0096] N-type semiconductor layer 50: The material is fullerene (C 60 The thickness is 28 nm; during preparation: the evaporation rate is...

[0097] Buffer layer 60: The material is copper bath (BCP), with a thickness of 6 nm; during preparation: the evaporation rate is...

[0098] Back electrode 70: Material is silver (Ag), thickness is 100nm; during fabrication: first reduce the internal air pressure of the machine to 5×10⁻⁶. -4 Pa, then begin preparing the metallic silver electrode. When the thickness of the silver electrode is between 0 and 5 nm, control the evaporation rate to [value missing]. Subsequently, the evaporation rate increases for every 5nm increase in thickness. Ultimately, the evaporation rate will be maintained at Until the vapor deposition is complete.

[0099] Figure 2 is a scanning electron microscope (SEM) image of the perovskite thin film prepared by the preparation method provided in this application. The SEM image shows the microstructure of the perovskite thin film surface. It can be seen from the figure that the prepared perovskite thin film has uniform and dense grains, a smooth surface, and no obvious pores or cracks. This indicates that the film formed a uniform grain distribution and a good crystal structure during the deposition process.

[0100] Figure 3 shows the external quantum efficiency of the perovskite infrared detector prepared by the method provided in this application as a function of irradiation wavelength. As can be seen from the figure, the perovskite infrared detector exhibits excellent detection capability in the wavelength range of 300 nm to 1100 nm. At a wavelength of 540 nm, the detector reaches a peak external quantum efficiency of 87.7%. In the near-ultraviolet to visible light (300 nm to 700 nm) range, the external quantum efficiency of the detector still shows a stable and high value, indicating that it has a good response capability to short wavelength light. At the same time, in the near-infrared (780 nm to 1100 nm) range, although the external quantum efficiency decreases, it still maintains high detection performance.

[0101] Figure 4 shows the responsivity curve of the perovskite infrared detector prepared by the preparation method provided in this application as a function of irradiation wavelength. As can be seen from the figure, the responsivity of the detector array is 0.47 A / W at a wavelength of 840 nm, which indicates the excellent photoelectric conversion capability of the prepared perovskite infrared detector array in the near-infrared band.

[0102] Figure 5 shows the response time of the perovskite infrared detector prepared by the preparation method provided in this application. As can be seen from the figure, the rise time of the detector array is 377.3 ns and the fall time is 860.1 ns. The detector array prepared in this application significantly surpasses the current leading level of perovskite infrared detector arrays in terms of response speed, achieving an ultrafast response speed of hundreds of nanoseconds.

[0103] FIG. 6 is a graph showing the variation of the specific detectivity of the perovskite infrared detector prepared by the preparation method provided in this application with the irradiation wavelength. As can be seen from the figure, at a wavelength of 840 nm, the specific detectivity of the detector array is 8.3×10 13 Jones, which indicates that the detector has extremely high response ability to the infrared band.

[0104] FIG. 7 is an imaging result diagram of the 5×5 infrared detector array provided in this application for the letter "S" under 980 nm light illumination. As can be seen from the figure, under the irradiation of 980 nm infrared radiation, the pixel shows an observable photocurrent of about 0.985 μA, while other regions show very weak dark currents, and the shape contour of the letter "S" can be clearly observed in the current contrast mapping, having good resolution.

[0105] FIG. 8 is an imaging result diagram of the 64×64 imaging chip based on the TFT readout circuit provided in this application for the Chinese character "Shanda" under 980 nm infrared radiation illumination. Under the irradiation of 980 nm infrared radiation, the Chinese character "Shanda" can be clearly observed, having good resolution.

[0106] In this application, under the combined action of optimization means such as a specific detector structure, the optimal thickness and material components of each layer of thin film in the structure, the optimization means adopted in the preparation process, the optimal control ratio of each component, and the optimal parameters of each process step, a perovskite infrared detector with the best performance is finally obtained. This detector can achieve efficient detection in a wide spectral range of 300 nm to 1100 nm, with a peak external quantum efficiency of up to 87.7%, a responsivity of 0.47 A / W, a specific detectivity as high as 8.3×10 13 Jones, a response time as short as 377.3 ns / 860.1 ns, can be compatible and integrated with CMOS or TFT chips, and realizes integrated imaging applications with 64×64 TFT chips, solving the technical problems that have always existed in the existing infrared detector manufacturing technology, such as high production costs of high-vacuum and high-temperature processes, low detectivity of devices, slow response speed, and inability to be compatible and integrated with heterogeneous chips.

[0107] In summary, this application realizes a high-performance, wide-spectrum infrared detector array and an infrared imaging chip compatible with complementary metal oxide semiconductor (CMOS) or thin film transistor (TFT) readout circuits through scalable solution processing technology, ultrafast laser processing technology, and vertical heterostacked device preparation methods, significantly reducing the manufacturing cost of the infrared imaging chip, improving the response speed of the infrared detector and the imaging quality of the chip, and having outstanding substantive features and remarkable technological progress.

[0108] In the description of this application, it should be understood that the terms "above" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this application.

[0109] Furthermore, in this application, unless otherwise expressly specified and limited, the term "setup" and other such terms should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can refer to a mechanical connection, an electrical connection, or a connection that allows communication between the components; it can refer to a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0110] Although preferred embodiments of this application have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this application.

[0111] Obviously, those skilled in the art can make various modifications and variations to this application without departing from the spirit and scope of this application. Therefore, if such modifications and variations fall within the scope of the claims of this application and their equivalents, this application also intends to include such modifications and variations.

Claims

1. A perovskite infrared detector structure, characterized in that: include: Substrate (10); P-type semiconductor layer (20): disposed on the substrate (10); Alumina layer (30): disposed on P-type semiconductor layer (20); Photosensitive perovskite layer (40): disposed on alumina layer (30); N-type semiconductor layer (50): disposed on photosensitive perovskite layer (40); Buffer layer (60): disposed on N-type semiconductor layer (50); Back electrode (70): disposed on the buffer layer (60).

2. The perovskite infrared detector structure according to claim 1, characterized in that: The photosensitive perovskite layer (40) is prepared from a narrow bandgap metal halide FA. 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3 has an optical band gap of <1.26 eV.

3. The perovskite infrared detector structure according to claim 1, characterized in that: The substrate (10) is made of indium-doped tin oxide. The material used to prepare the P-type semiconductor layer (20) is [6-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid; The N-type semiconductor layer (50) is made of fullerene; The buffer layer (60) is made of copper bath compound; The back electrode (70) is made of silver.

4. The perovskite infrared detector structure according to any one of claims 1 to 3, characterized in that: The thickness of the P-type semiconductor layer (20) ranges from 10 to 20 nm; The thickness of the alumina layer (30) is in the range of 20-30 nm; The thickness of the photosensitive perovskite layer (40) ranges from 400 to 500 nm; The thickness of the N-type semiconductor layer (50) ranges from 25 to 30 nm; The thickness of the buffer layer (60) ranges from 5 to 7 nm; The thickness of the back electrode (70) ranges from 80 to 120 nm.

5. The perovskite infrared detector structure according to any one of claims 1 to 3, characterized in that: The thickness of the P-type semiconductor layer (20) is 15 nm; The thickness of the alumina layer (30) is 30 nm; The thickness of the photosensitive perovskite layer (40) is 440 nm; The thickness of the N-type semiconductor layer (50) is 28 nm; The thickness of the buffer layer (60) is 6 nm; The thickness of the back electrode (70) is 100 nm.

6. A method for fabricating a perovskite infrared detector structure as described in any one of claims 1 to 3, characterized in that: include: S10, Provide substrate (10); S20. The P-type semiconductor material is processed by spin coating process to form a P-type semiconductor layer (20) on the substrate (10); S30. The nano-alumina material is processed by spin coating to form an alumina layer (30) on the P-type semiconductor layer (20); S40. The perovskite precursor material is processed by spin coating process to form a photosensitive perovskite layer (40) on the alumina layer (30); S50. The N-type semiconductor material is processed by vacuum evaporation to form an N-type semiconductor layer (50) on the photosensitive perovskite layer (40). S60. A buffer layer (60) is formed on the N-type semiconductor layer (50) using a vacuum evaporation process; S70. The conductive material is processed by vacuum evaporation to form a back electrode (70) on the buffer layer (60).

7. The method for fabricating the perovskite infrared detector structure according to claim 6, characterized in that: Step S40 specifically includes: Weigh out appropriate amounts of methylammonium iodide, methylamine iodide, lead iodide, and stannous iodide; Then, a mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide in a volume ratio ranging from 3:1 to 5:1 is added, and the mixture is stirred at room temperature until completely dissolved to obtain FA. 0.7 MA 0.3 Pb 0.5 Sn 0.5 I3 perovskite precursor solution; The perovskite precursor solution was spin-coated onto the alumina layer (30), and chlorobenzene anti-solvent was added dropwise during the spin-coating process; After spin coating, annealing is performed to obtain a perovskite film, forming a photosensitive perovskite layer (40).

8. The method for fabricating the perovskite infrared detector structure according to claim 7, characterized in that: In step S40: The molar ratio of methylammonium iodide, methylamine iodide, lead iodide and stannous iodide weighed out is 7:3:5:5; The volume ratio of the mixed solvent of N,N-dimethylformamide and dimethyl sulfoxide is 4:1; The obtained FA 0.7 MA 0.3 Pb 0.5 Sn 0.5 The concentration of the I3 perovskite precursor solution was 1.1 mol / L; When spin-coating the perovskite precursor solution, the volume of the perovskite precursor solution is 120 μL, the spin coater speed is 6000 rpm, the acceleration is 3000 rpm, and the time is 60 seconds; at the 45th second of spin coating, 350 μL of chlorobenzene antisolvent is added dropwise. After spin coating, the film was annealed at 100°C for 10 minutes to obtain a perovskite film with a thickness of 440 nm, forming a photosensitive perovskite layer (40).

9. The method for fabricating the perovskite infrared detector structure according to claim 8, characterized in that: Step S10 specifically includes: Provide a substrate (10) and perform the following cleaning treatment on the substrate (10): first use a cleaning agent to ultrasonically clean for 20 minutes, then use deionized water, anhydrous ethanol, acetone and isopropanol to ultrasonically clean for 20 minutes respectively, then dry for 30 minutes, finally clean the surface again with nitrogen, and then use ozone treatment for 20 minutes before use. Step S20 specifically includes: [6-(3,6-dimethoxy-9H-carbazole-9-yl)butyl]phosphonic acid was first dissolved in ethanol to form a solution with a concentration of 2 mg / mL. Then, 120 μL of the solution was spin-coated onto the cleaned substrate (10). The spin coater was operated at a speed of 6000 rpm, an acceleration of 3000 rpm, and a time of 30 seconds. After spin coating, the substrate was annealed at 100 °C for 10 minutes to obtain a P-type semiconductor layer (20) with a thickness of 15 nm. Step S30 specifically includes: First, the nano-alumina solution was diluted in isopropanol at a volume ratio of 1:

20. Then, 150 μL of the diluted solution was spin-coated onto the P-type semiconductor layer (20). The spin coater was operated at a speed of 6000 rpm, an acceleration of 3000 rpm, and a time of 30 seconds. After spin coating, the layer was annealed at 120°C for 20 minutes to obtain an alumina layer (30) with a thickness of 30 nm. Step S50 specifically includes: Fullerene material was deposited on the photosensitive perovskite layer (40) using a vacuum evaporation process to obtain an N-type semiconductor layer (50) with a thickness of 28 nm, wherein: the evaporation rate was Step S60 specifically includes: A copper bath material was deposited on an N-type semiconductor layer (50) using a vacuum evaporation process to obtain a buffer layer (60) with a thickness of 6 nm, wherein the evaporation rate was... Step S70 specifically includes: After placing the device into the vacuum coating machine, first reduce the internal air pressure of the machine to 5×10. -4 Pa, then begin preparing the metallic silver electrode; when the thickness of the silver electrode is between 0 and 5 nm, control the evaporation rate to [value missing]. Subsequently, the evaporation rate increases for every 5nm increase in thickness. Ultimately, the evaporation rate will be maintained at Until the vapor deposition is complete.

10. An infrared imaging chip, characterized in that: include: Photodetector: an array structure formed by the perovskite infrared detector structure according to any one of claims 1 to 3, wherein the array structure is fabricated by an ultrafast laser etching process and is used to convert the received infrared radiation signal into a readable current signal. TFT readout circuit: Electrically connected to the photodetector, used to read the current signal output by the photodetector, form a corresponding pattern based on the reading result, and perform image output.

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