A perovskite-based multi-polarity photoelectric detector and a preparation method thereof

Abstract

This invention discloses a perovskite-based multipolar photodetector, belonging to the field of photodetector technology. It includes a single-layer polished silicon oxide substrate, a first metal electrode, a second metal electrode, a first metal metasurface array, a second metal metasurface array, and a perovskite thermoelectric and optical absorption layer. The single-layer polished silicon oxide substrate comprises a monocrystalline silicon layer and a silicon oxide layer, with the silicon oxide layer located on the monocrystalline silicon layer. The first and second metal electrodes are independently distributed at opposite ends of the silicon oxide layer. The first and second metal metasurface arrays are distributed on the silicon oxide layer and sandwiched within a channel between the first and second metal electrodes. The perovskite thermoelectric and optical absorption layer covers the first metal electrode, the second metal electrode, the first metal metasurface array, and the second metal metasurface array, and is in ohmic contact with the first and second metal electrodes. This invention integrates the detection of near-infrared, mid-infrared, and visible light at specific wavelengths.

Description

Technical Field

[0001] This invention relates to the field of photodetector technology, and specifically to a perovskite-based multipolar photodetector and its fabrication method. Background Technology

[0002] As a core component of optoelectronic systems, photodetectors convert incident light signals into electrical signals, playing a crucial role in optoelectronic displays, environmental monitoring, optical communication, military applications, and security inspections. With the development of semiconductor micro-nano fabrication technology, photodetectors are trending towards miniaturization and integration. Traditional on-chip integrated photodetectors often only enable single-wavelength detection; achieving multi-band detection requires multiple photodetectors, resulting in high costs and large size. In contrast, multipolar photodetectors can achieve multi-band or polarization detection on a single optical chip. For example, patent number CN202311792932.X describes a bipolar photodetector and optical encryption communication system and method, which provides a bipolar photodetector that, under TM polarized light incident light and with zero bias, can excite response currents of opposite polarities in the short-wavelength and long-wavelength bands respectively. However, it requires low-temperature operation, which not only increases the system's complexity and cost but also limits its portability and widespread adoption in practical applications.

[0003] Metasurfaces are periodic arrays whose resonant absorption bands can be flexibly controlled by adjusting the unit structure. They are widely used in the field of photodetectors, especially in the area of ​​localized surface plasmon resonance (LSPR)-induced electron-phonon collisions, which can achieve light absorption and efficient photothermal conversion in specific wavelength bands. For example, patent CN202010749805.1 describes a narrowband photodetector based on thermoelectric materials, which focuses on the narrowband absorption characteristics of metamaterials and achieves near-infrared / mid-infrared unbiased response by combining thermoelectric materials and metamaterials, attempting to solve the power consumption and complexity problems caused by traditional detectors that rely on cooling or bias. Another example is patent CN202010327903.6, which describes a thermionic photodetector based on perfectly absorbing metamaterials and its fabrication method. By adjusting the geometric dimensions of the periodic metamaterial, the detection range of the thermionic photodetector can be controlled, providing a new approach for the design of metasurfaces in photodetectors. However, these traditional detectors that achieve wavelength detection by combining thermoelectric materials and metamaterials only achieve single-wavelength detection and cannot meet the requirements for the integration of photodetectors.

[0004] Organic-inorganic hybrid halide perovskites (CH3NH3PbX3, X = Cl, Br, I) possess excellent semiconductor properties, such as high absorption coefficients and long carrier diffusion lengths. They exhibit high light absorption coefficients in the visible light range (380-780 nm), thus often serving as light-absorbing layers in photodetectors. Furthermore, perovskites possess low thermal conductivity and high Seebeck coefficients, making them excellent thermoelectric materials. However, pure perovskite detectors rely on the band gap limitation of the perovskite material itself for wavelength detection, making it difficult to detect near-infrared and even mid-infrared wavelengths.

[0005] Therefore, how to develop a compact on-chip integrated photodetector that can simultaneously detect visible light, near-infrared light, and mid-infrared light has become a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] Therefore, the present invention provides a perovskite-based multipolar photodetector to solve the problem that existing photodetectors can only detect a single wavelength, which makes it impossible to meet the requirements for photodetector integration.

[0007] To achieve the above objectives, the present invention provides the following technical solution: According to a first aspect of the present invention, this application provides a perovskite-based multipolar photodetector, comprising a single-polished silicon oxide substrate, a first metal electrode, a second metal electrode, a first metal metasurface array, a second metal metasurface array, and a perovskite thermoelectric and optical absorption layer. The single-polished silicon oxide substrate comprises a single-crystal silicon layer and a silicon oxide layer, the silicon oxide layer being located on the single-crystal silicon layer. The first metal electrode and the second metal electrode are independently distributed at both ends on the silicon oxide layer. The first metal metasurface array and the second metal metasurface array are distributed on the silicon oxide layer and sandwiched in a channel between the first metal electrode and the second metal electrode. The perovskite thermoelectric and optical absorption layer covers the first metal electrode, the second metal electrode, the first metal metasurface array, and the second metal metasurface array, and is in ohmic contact with the first metal electrode and the second metal electrode.

[0008] Furthermore, the first metal electrode, the second metal electrode, the first metal metasurface array, and the second metal metasurface array all adopt a composite metal layer structure. The composite metal layer structure uses chromium as the bottom adhesion layer and gold as the top conductive layer. The thickness of chromium in the composite metal layer structure is 5-10 nm, and the thickness of gold is 30-50 nm.

[0009] Furthermore, the length of the perovskite-based multipolar photodetector is 15-34 μm, the width is 5-15 μm, the width between the first metal electrode and the second metal electrode is 10-30 μm, the thickness of the silicon oxide layer is 250-300 nm, and the thickness of the perovskite thermoelectric and optical absorption layer is 200-400 nm.

[0010] According to a second aspect of the present invention, this application provides a method for fabricating a perovskite-based multipolar photodetector, for fabricating the perovskite-based multipolar photodetector described in any of the above claims, comprising the following steps: Step S1: Perform ultrasonic cleaning on the P-type doped single-layer polished silicon oxide wafer; Step S2: Dry the ultrasonically cleaned single-polished silicon oxide wafer to obtain a clean single-polished silicon oxide substrate; Step S3: Use deep ultraviolet lithography to define the first metal electrode and the second metal electrode patterns at both ends of the single-sided polished silicon oxide substrate obtained in step S2. Then, perform vapor deposition of the first metal electrode and the second metal electrode, and obtain the first metal electrode and the second metal electrode through a stripping process. Step S4: Design the photolithographic masks corresponding to the first and second metal metasurface arrays; Step S5: Based on the photolithographic mask designed in step S4, transfer the patterns of the first metal metasurface array and the second metal metasurface array into the channel between the first metal electrode and the second metal electrode. Step S6: Prepare a perovskite precursor solution and spin-coat it onto the first metal electrode, the second metal electrode, the first metal metasurface array, and the second metal metasurface array to obtain a multipolar photodetector covered with a perovskite thermoelectric and optical absorption layer.

[0011] Furthermore, step S1 specifically includes: placing the P-type doped single-sided polished silicon oxide wafer into deionized water, acetone solution and anhydrous ethanol solution in sequence for ultrasonic treatment for 5-10 minutes each.

[0012] Furthermore, step S2 specifically includes: drying the ultrasonically cleaned single-sided polished silicon oxide wafer with nitrogen gas and drying it at 100°C for 5 minutes to obtain a clean single-sided polished silicon oxide substrate.

[0013] Furthermore, step S3 specifically includes: Step S301: Spin-coat photoresist onto a single-layer polished silicon oxide substrate and pre-bake at 90-120℃ for 5-10 minutes; Step S302: Design the photolithographic mask templates corresponding to the first metal electrode and the second metal electrode; Step S303: Based on the photolithography mask of step S302, apply deep ultraviolet exposure to both ends of the single-polished silicon oxide substrate of step S301; Step S304: After exposure, the single-polished silicon oxide substrate is removed from the photolithography machine, placed in the developing solution for developing treatment, rinsed with deionized water and dried with nitrogen gas, and then the first metal electrode and the second metal electrode are deposited by vapor deposition. Step S305: Immerse the evaporated single-layer polished silicon oxide substrate in acetone solvent to dissolve the photoresist; Step S306: After rinsing the dissolved single-sided polished silicon oxide substrate with deionized water and ethanol, it is dried with nitrogen gas to obtain a single-sided polished silicon oxide substrate covered with the first metal electrode and the second metal electrode.

[0014] Furthermore, step S4 specifically includes: In electromagnetic simulation software, the first metal metasurface array is designed by adjusting the geometric dimensions and period of the metasurface unit, so that the first metal metasurface array forms an absorption peak at any wavelength in the near infrared. The second metal metasurface array is designed by adjusting the geometry and period of the metasurface unit, so that the second metal metasurface array forms an absorption peak at any wavelength in the mid-infrared. Based on the geometric dimensions and period of the first and second metal metasurface arrays, the corresponding photolithography mask is designed.

[0015] Furthermore, step S5 specifically includes: Spin-coat photoresist onto a single-polished silicon oxide substrate covered with the first and second metal electrodes, and pre-bake at 90-120°C for 5-10 minutes. Align the photomask designed in step S4 with the channel of the single-polished silicon oxide substrate and expose it using electron beam direct writing. After exposure, the single-polished silicon oxide substrate is placed in the developer solution for development. After being taken out, it is rinsed with deionized water and dried with nitrogen gas. Then, the first metal metasurface array and the second metal metasurface array are vapor deposited. The evaporated single-polished silicon oxide substrate is immersed in acetone solvent to dissolve the photoresist. After rinsing the dissolved single-sided polished silicon oxide substrate with deionized water and ethanol, it is dried with nitrogen gas. The patterns of the first metal metasurface array and the second metal metasurface array are transferred into the channel between the first metal electrode and the second metal electrode to obtain a single-sided polished silicon oxide substrate covered with the first metal metasurface array, the second metal metasurface array, the first metal electrode and the second metal electrode.

[0016] Furthermore, step S6 specifically includes: A single-sided polished silicon oxide substrate covered with a first metal metasurface array, a second metal metasurface array, a first metal electrode, and a second metal electrode is placed in a spin coater. A perovskite precursor solution is added dropwise for spin coating, followed by the addition of chlorobenzene as a spin coating anti-solvent. The substrate is then placed on a heating stage and annealed at 100°C for 15 minutes to form a perovskite light-absorbing and thermoelectric layer. This perovskite light-absorbing and thermoelectric layer is then brought into ohmic contact with the first and second metal electrodes to obtain a multipolar photodetector covered with a perovskite thermoelectric and light-absorbing layer.

[0017] The present invention has the following advantages: The photodetector designed in this invention features a photothermoelectric bipolar response that eliminates the need for cooling, enabling detection of specific wavelengths. The spin-coated perovskite light-absorbing and thermoelectric layer allows for broadband detection in the visible light band, which is of significant importance in visible light communication. Furthermore, by applying two metal metasurface arrays of different sizes to the photodetector, the absorption peak of the plasmonic resonance can be adjusted by modifying the size of the metasurface units, thus achieving positive and negative polarity detection of specific wavelengths in the near-infrared and mid-infrared regions. Compared to traditional visible, near-infrared, and mid-infrared detectors, this invention boasts high integration, miniaturization, and low cost, achieving detection of all three bands using only a single on-chip integrated device. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0019] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0020] Figure 1 A perspective view of the multipolar photodetector provided in Embodiment 1 of the present invention; Figure 2 This is a front view of the multipolar photodetector provided in Embodiment 1 of the present invention; Figure 3 This is a top view of the multipolar photodetector provided in Embodiment 1 of the present invention; Figure 4This is a schematic diagram of the temperature and potential distribution in the channel of the multipolar photodetector provided in Embodiment 1 of the present invention under 1910nm near-infrared light irradiation. Figure 5 This is a schematic diagram of the temperature and potential distribution in the channel of the multipolar photodetector provided in Embodiment 1 of the present invention under 4600nm mid-infrared light irradiation. Figure 6 This is a schematic diagram of the surface structure of the first metal metasurface array or the second metal metasurface array provided in Embodiment 2 of the present invention; Figure 7 This is a schematic diagram showing the temperature and potential distribution in the channel of the multipolar photodetector provided in Comparative Example 1 of the present invention under 1910nm near-infrared light irradiation. Figure 8 This is a schematic diagram showing the temperature and potential distribution in the channel of the multipolar photodetector provided in Comparative Example 1 of the present invention under 4600nm mid-infrared light irradiation.

[0021] In the picture: 1. Single-crystal silicon layer; 2. Silicon oxide layer; 3. First metal electrode; 4. Second metal electrode; 5. First metal metasurface array; 6. Second metal metasurface array; 7. Perovskite thermoelectric and optical absorption layer. Detailed Implementation

[0022] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] Example 1 This embodiment provides a perovskite-based multipolar photodetector, such as... Figures 1-3 As shown, the device includes a single-polished silicon oxide substrate, a first metal electrode 3, a second metal electrode 4, a first metal metasurface array 5, a second metal metasurface array 6, and a perovskite thermoelectric and optical absorption layer 7. The single-polished silicon oxide substrate includes a single-crystal silicon layer 1 and a silicon oxide layer 2. The silicon oxide layer 2 is located on the single-crystal silicon layer 1. The first metal electrode 3 and the second metal electrode 4 are independently distributed at both ends of the silicon oxide layer 2. The first metal metasurface array 5 and the second metal metasurface array 6 are distributed on the silicon oxide layer 2 and sandwiched in the channel between the first metal electrode 3 and the second metal electrode 4. The perovskite thermoelectric and optical absorption layer 7 covers the first metal electrode 3, the second metal electrode 4, the first metal metasurface array 5, and the second metal metasurface array 6 and is in ohmic contact with the first metal electrode 3 and the second metal electrode 4.

[0024] The first metal electrode 3, the second metal electrode 4, the first metal metasurface array 5, and the second metal metasurface array 6 all adopt a composite metal layer structure. The composite metal layer structure uses chromium (Cr) as the bottom adhesion layer and gold (Au) as the top conductive layer. The thickness of the chromium layer is 5-10 nm, and the thickness of the gold layer is 30-50 nm. Preferably, the thickness of the chromium layer is 5 nm, and the thickness of the gold layer is 50 nm.

[0025] The sizes of the first metal metasurface array 5 and the second metal metasurface array 6 are adjusted according to the detection wavelength.

[0026] The specific dimensions of the first metal metasurface array 5 and the second metal metasurface array 6 are designed as follows: The first metal metasurface array 5 is a cylindrical array containing 9*6 cells arranged at uniform intervals. The radius of the cylinder is 195nm, the lattice period is 940nm, and the height is 5nmCr / 50nmAu.

[0027] The second metal metasurface array 6 is a cylindrical array containing 5*4 cells arranged at uniform intervals. The radius of the cylinder is 395nm, the lattice period is 2580nm, and the height is 5nmCr / 50nmAu.

[0028] The perovskite-based multipolar photodetector has a length of 15-34 μm and a width of 5-15 μm. The width between the first metal electrode 3 and the second metal electrode 4 is 10-30 μm. The thickness of the silicon oxide layer 2 is 250-300 nm, and the thickness of the perovskite thermoelectric and optical absorption layer 7 is 200-400 nm.

[0029] Preferably, the specific dimensions of the multipolar photodetector provided by the present invention are designed as follows: the overall length of the multipolar photodetector is 30 μm, the width is 15 μm, the thickness of the single crystal silicon layer 1 is 5 μm, the thickness of the silicon oxide layer 2 is 300 nm, and the thickness of the perovskite thermoelectric and photoabsorbing layer 7 is 300 nm.

[0030] At a specific wavelength, the heat generated by the local field enhancement effect of any cylindrical metal metasurface array will induce uneven temperature distribution in the device channel. This temperature difference is further converted into a potential difference through the Seebeck effect. The two sizes of cylindrical metal metasurface arrays correspond to two polarities of photothermal and electrical effects. In addition, the perovskite layer itself, besides serving as a thermoelectric layer, also serves as a photoactive layer with good absorption effect for visible light (wavelength 380-780nm), which contributes a third polarity to the photodetector.

[0031] The photodetector provided in this application enables the detection of specific wavelengths in the near-infrared, mid-infrared, and the entire visible light range. Compared to other multipolar photodetectors, we are the first to incorporate the photothermoelectric effect. The positive and negative values ​​of the voltage signal generated by this effect strictly distinguish between mid-infrared and near-infrared wavelengths, exhibiting excellent characteristics such as no cooling required and zero self-bias. This overcomes the limitation of traditional photothermoelectric detectors that can only detect a single wavelength band. By adjusting the size of the metasurface, the absorption wavelength characteristics can be flexibly adjusted to achieve separate detection of the near-infrared and mid-infrared bands. By combining metasurface arrays of different sizes with perovskite materials, the device exhibits excellent bipolar photothermoelectric and photoconductive effects, driving the development of photodetectors towards greater integration, smaller size, and lower cost.

[0032] This embodiment also provides a method for fabricating a perovskite-based multipolar photodetector, including the following steps: Step S1: Perform ultrasonic cleaning on the P-type doped single-sided polished silicon oxide wafer. Specifically, immerse the P-type doped single-sided polished silicon oxide wafer in deionized water, acetone solution, and anhydrous ethanol solution sequentially for ultrasonic treatment for 5-10 minutes each.

[0033] Step S2: Dry the ultrasonically cleaned single-sided polished silicon oxide wafer to obtain a clean single-sided polished silicon oxide substrate. Specifically, the ultrasonically cleaned single-sided polished silicon oxide wafer is dried with nitrogen gas and then dried at 100°C for 5 minutes to obtain a clean single-sided polished silicon oxide substrate.

[0034] Step S3: Use deep ultraviolet lithography to define the patterns of the first metal electrode 3 and the second metal electrode 4 at both ends of the single-sided polished silicon oxide substrate obtained in step S2. Then, perform vapor deposition of the first metal electrode 3 and the second metal electrode 4, and obtain the first metal electrode 3 and the second metal electrode 4 through a stripping process.

[0035] Specifically, photoresist is spin-coated onto a single-layer polished silicon oxide substrate and pre-baked at 90-120℃ for 5-10 minutes; photomasks corresponding to the first metal electrode 3 and the second metal electrode 4 are designed; based on the photomasks corresponding to the first metal electrode 3 and the second metal electrode 4, the two ends of the dried single-layer polished silicon oxide substrate are exposed to deep ultraviolet light; the exposed single-layer polished silicon oxide substrate is removed from the photolithography machine and placed in a developing solution for development treatment. The developing solution is rinsed clean with deionized water and dried with nitrogen gas, followed by vapor deposition of the first metal electrode 3 and the second metal electrode 4; the vapor-deposited single-layer polished silicon oxide substrate is immersed in acetone solvent to dissolve the photoresist; the dissolved single-layer polished silicon oxide substrate is rinsed clean with deionized water and ethanol and dried with nitrogen gas to obtain a single-layer polished silicon oxide substrate covered with the first metal electrode 3 and the second metal electrode 4.

[0036] Step S4: Design the photolithographic mask templates corresponding to the first metal metasurface array 5 and the second metal metasurface array 6.

[0037] Specifically, in the electromagnetic simulation software, the first metal metasurface array 5 is designed by adjusting the geometric dimensions and period of the metasurface units, so that the first metal metasurface array 5 forms an absorption peak at any wavelength in the near-infrared region; the second metal metasurface array 6 is designed by adjusting the geometric dimensions and period of the metasurface units, so that the second metal metasurface array 6 forms an absorption peak at any wavelength in the mid-infrared region; and the corresponding photolithography mask is designed according to the geometric dimensions and period of the first metal metasurface array 5 and the second metal metasurface array 6.

[0038] Preferably, in this embodiment, the first metal metasurface array 5 is designed by adjusting the radius and period of the cylindrical units in the Comsol electromagnetic simulation software, so that it forms an absorption peak at a wavelength of 1910 nm. The cylindrical radius of the first metal metasurface array 5 is 195 nm, and the lattice period is 940 nm. Similarly, the second metal metasurface array 6 is designed by adjusting the radius and period of the cylindrical units again, so that it forms an absorption peak at a wavelength of 4600 nm. The cylindrical radius of the second metal metasurface array 6 is 395 nm, and the lattice period is 2580 nm. Photolithographic masks of corresponding sizes are fabricated based on the two cylindrical metasurfaces.

[0039] Step S5: Based on the photolithographic mask designed in step S4, transfer the patterns of the first metal metasurface array 5 and the second metal metasurface array 6 into the channel between the first metal electrode 3 and the second metal electrode 4.

[0040] Specifically, a single-polished silicon oxide substrate covered with the first metal electrode 3 and the second metal electrode 4 is spin-coated with photoresist and pre-baked at 90-120°C for 5-10 minutes; the photomask designed in step S4 is aligned with the channel of the single-polished silicon oxide substrate and exposed using electron beam direct writing; the exposed single-polished silicon oxide substrate is placed in a developer for development, then rinsed with deionized water and dried with nitrogen, followed by vapor deposition of the first metal metasurface array 5 and the second metal metasurface array 6; the vapor-deposited single-polished silicon oxide substrate is immersed in acetone solvent to dissolve the photoresist; the dissolved single-polished silicon oxide substrate is rinsed with deionized water and ethanol, dried with nitrogen, and the pattern of the first metal metasurface array 5 and the second metal metasurface array 6 is transferred into the channel between the first metal electrode 3 and the second metal electrode 4, resulting in a single-polished silicon oxide substrate with the patterns of the first metal metasurface array 5, the second metal metasurface array 6, the first metal electrode 3, and the second metal electrode 4 deposited.

[0041] Step S6: Prepare a perovskite precursor solution and spin-coat it onto the first metal electrode 3, the second metal electrode 4, the first metal metasurface array 5, and the second metal metasurface array 6 to obtain a multipolar photodetector covered with a perovskite thermoelectric and optical absorption layer 7.

[0042] Specifically, a perovskite precursor solution was prepared by heating and stirring a mixed solvent of 1.2 mmol lead iodide (553.2 mg) and 1.2 mmol dimethyl sulfoxide (190 mg) in a volume ratio of 9:1 at 70°C for 8 hours. A single-sided polished silicon oxide substrate covered with a first metal metasurface array 5, a second metal metasurface array 6, a first metal electrode 3, and a second metal electrode 4 was placed in a spin coater. The perovskite precursor solution was added dropwise and spin-coated at 3000 rpm for 10 seconds. Then, the spin-coating antisolvent chlorobenzene was added dropwise. The substrate was then placed on a heating stage and annealed at 100°C for 15 minutes to form a 300 nm thick perovskite light-absorbing and thermoelectric layer. The perovskite light-absorbing and thermoelectric layer was then made to form an ohmic contact with the first metal electrode 3 and the second metal electrode 4, resulting in a multipolar photodetector covered with a perovskite thermoelectric and light-absorbing layer 7.

[0043] To verify the beneficial effects of this embodiment, the following experiment was conducted: like Figure 4 As shown, in Comsol, electromagnetic heating and thermoelectric effects are continuously used in multi-physics field coupling. Near-infrared light of 1910nm is incident from the top of the device. At the midpoint of the 15μm width direction, at half the height of the first metal metasurface array 5 and the second metal metasurface array 6, 11 domain point probes are set along the lateral position of the channel in the 30μm length direction of the device. The relationship between the potential and temperature of these 11 points and their corresponding positions is measured. It can be seen that the highest temperature and the lowest potential are at the center of the first metal metasurface array 5.

[0044] like Figure 5 As shown, in Comsol, electromagnetic heating and thermoelectric effects are continuously used in multi-physics field coupling. Mid-infrared light of 4600nm is incident from the top of the device. At the midpoint of the 15μm width direction, at half the height of the first metal metasurface array 5 and the second metal metasurface array 6, 11 domain point probes are set along the lateral position of the channel in the 30μm length direction of the device. The relationship between the potential and temperature of these 11 points and their corresponding positions is measured. It can be seen that the highest temperature and the lowest potential are at the center of the second metal metasurface array 6.

[0045] Example 2 Based on Example 1, the patterns of the first metal metasurface array 5 and the second metal metasurface array 6 can also be designed in an "I" shape, such as... Figure 6The table shows the unit structure and related dimensions. The dimensions are labeled with the letters P, L, h, w, and d, respectively. Specific dimensional values ​​are shown in Table 1. Table 1. Relevant Dimensional Values ​​of Metallic "I" Metasurface Units

[0046] According to Comsol software simulation, the first metal metasurface array 5 forms an absorption peak at 1790 nm, and the second metal metasurface array 6 forms an absorption peak at 3780 nm. Furthermore, the relevant dimensional parameters can be further adjusted to further regulate the positive and negative detection wavelengths of this multipolar detector, thereby achieving precise detection of a narrow peak in the near-infrared / mid-infrared region and detection of visible light. In addition, due to the spin-coating of perovskite, the detector can also detect visible light (380-780 nm).

[0047] Comparative Example 1 Based on Example 1, the second metal metasurface array 6 is removed. Electromagnetic heating, thermoelectric effects, and multi-physics field coupling are continuously used in Comsol, with 1910nm near-infrared light irradiation, such as... Figure 7 As shown, it can be seen that the highest temperature and the lowest potential are located at the center of the first metal metasurface array 5; using 4600nm mid-infrared light incident on the upper surface of the device, such as Figure 8 As shown, because the device lacks the second metallic metasurface array 6 for mid-infrared light detection, it cannot simultaneously exhibit positive and negative polarity responses to both near-infrared and mid-infrared light. Therefore, by using two sets of metasurface arrays on a single photodetector, it is possible to simultaneously achieve positive and negative bipolar responses to both near-infrared and mid-infrared light, exhibiting a richer polarity than a photothermoelectric detector with a single metasurface array.

[0048] Comparative Example 2 Based on Example 1, the perovskite thermoelectric and optical absorption layer 7 was removed. The photodetector can only exhibit a positive and negative bipolar response to a single wavelength in the near-infrared and mid-infrared ranges, and cannot respond to visible light (380-780nm).

[0049] The perovskite-based multipolar photodetector provided by this invention utilizes perovskite as a thermoelectric material and light-absorbing layer with bipolar response for both metasurfaces. This not only enables positive and negative bipolar responses to single wavelengths in the near-infrared and mid-infrared regions but also allows for detection in the visible light band. Therefore, this structure exhibits a richer response polarity than a simple positive and negative bipolar photothermoelectric detector.

[0050] The photodetector designed in this invention features a photothermoelectric bipolar response that eliminates the need for cooling, enabling detection of specific wavelengths. The spin-coated perovskite light-absorbing and thermoelectric layer allows for broadband detection in the visible light band, which is of significant importance in visible light communication. Furthermore, by applying two metal metasurface arrays of different sizes to the photodetector, the absorption peak of the plasmonic resonance can be adjusted by modifying the size of the metasurface units, thus achieving positive and negative polarity detection of specific wavelengths in the near-infrared and mid-infrared regions. Compared to traditional visible, near-infrared, and mid-infrared detectors, this invention boasts high integration, miniaturization, and low cost, achieving detection of all three bands using only a single on-chip integrated device.

[0051] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A perovskite-based multi-polar photodetector, characterized in that, The device includes a single-polished silicon oxide substrate, a first metal electrode, a second metal electrode, a first metal metasurface array, a second metal metasurface array, and a perovskite thermoelectric and optical absorption layer. The single-polished silicon oxide substrate includes a single-crystal silicon layer and a silicon oxide layer, with the silicon oxide layer located on the single-crystal silicon layer. The first metal electrode and the second metal electrode are independently distributed at both ends of the silicon oxide layer. The first metal metasurface array and the second metal metasurface array are distributed on the silicon oxide layer and sandwiched in a channel between the first metal electrode and the second metal electrode. The perovskite thermoelectric and optical absorption layer covers the first metal electrode, the second metal electrode, the first metal metasurface array, and the second metal metasurface array, and is in ohmic contact with the first metal electrode and the second metal electrode. The first metal metasurface array is designed by adjusting the geometric dimensions and period of the metasurface unit, so that the first metal metasurface array forms an absorption peak at any wavelength in the near infrared. The second metal metasurface array is designed by adjusting the geometry and period of the metasurface unit, so that the second metal metasurface array forms an absorption peak at any wavelength in the mid-infrared.

2. The perovskite-based multi-polar photodetector of claim 1, wherein, The first metal electrode, the second metal electrode, the first metal metasurface array, and the second metal metasurface array all adopt a composite metal layer structure. The composite metal layer structure uses chromium as the bottom adhesion layer and gold as the top conductive layer. The thickness of chromium in the composite metal layer structure is 5-10 nm, and the thickness of gold is 30-50 nm.

3. The perovskite-based multi-polar photodetector of claim 1, wherein, The perovskite-based multipolar photodetector has a length of 15-34 μm and a width of 5-15 μm. The width between the first metal electrode and the second metal electrode is 10-30 μm. The thickness of the silicon oxide layer is 250-300 nm, and the thickness of the perovskite thermoelectric and optical absorption layer is 200-400 nm.

4. A method for the preparation of a multi-polar photodetector based on perovskite for the preparation of a multi-polar photodetector based on perovskite according to any one of claims 1 to 3, characterized in that, Includes the following steps: Step S1: Perform ultrasonic cleaning on the P-type doped single-layer polished silicon oxide wafer; Step S2: Dry the ultrasonically cleaned single-polished silicon oxide wafer to obtain a clean single-polished silicon oxide substrate; Step S3: Use deep ultraviolet lithography to define the first metal electrode and the second metal electrode patterns at both ends of the single-sided polished silicon oxide substrate obtained in step S2. Then, perform vapor deposition of the first metal electrode and the second metal electrode, and obtain the first metal electrode and the second metal electrode through a stripping process. Step S4: Design the photolithographic masks corresponding to the first and second metal metasurface arrays; Step S5: Based on the photolithographic mask designed in step S4, transfer the patterns of the first metal metasurface array and the second metal metasurface array into the channel between the first metal electrode and the second metal electrode. Step S6: Prepare a perovskite precursor solution and spin-coat it onto the first metal electrode, the second metal electrode, the first metal metasurface array, and the second metal metasurface array to obtain a multipolar photodetector covered with a perovskite thermoelectric and optical absorption layer.

5. The method of claim 4, wherein the perovskite-based multi-polar photodetector is prepared by the steps of: Step S1 specifically includes: placing a P-type doped single-sided polished silicon oxide wafer into deionized water, acetone solution, and anhydrous ethanol solution in sequence for ultrasonic treatment for 5-10 minutes each.

6. The method of claim 4, wherein the perovskite-based multi-polar photodetector is prepared by the steps of: Step S2 specifically includes: drying the ultrasonically cleaned single-sided polished silicon oxide wafer with nitrogen gas and drying it at 100°C for 5 minutes to obtain a clean single-sided polished silicon oxide substrate.

7. The fabrication method of the perovskite-based multipolar photodetector as described in claim 4, characterized in that, Step S3 specifically includes: Step S301: Spin-coat photoresist onto a single-layer polished silicon oxide substrate and pre-bake at 90-120℃ for 5-10 minutes; Step S302: Design the photolithographic mask templates corresponding to the first metal electrode and the second metal electrode; Step S303: Based on the photolithography mask of step S302, apply deep ultraviolet exposure to both ends of the single-polished silicon oxide substrate of step S301; Step S304: After exposure, the single-polished silicon oxide substrate is removed from the photolithography machine, placed in the developing solution for developing treatment, rinsed with deionized water and dried with nitrogen gas, and then the first metal electrode and the second metal electrode are deposited by vapor deposition. Step S305: Immerse the evaporated single-layer polished silicon oxide substrate in acetone solvent to dissolve the photoresist; Step S306: After rinsing the dissolved single-sided polished silicon oxide substrate with deionized water and ethanol, it is dried with nitrogen gas to obtain a single-sided polished silicon oxide substrate covered with the first metal electrode and the second metal electrode.

8. The method for fabricating a perovskite-based multipolar photodetector as described in claim 4, characterized in that, Step S4 specifically includes: In electromagnetic simulation software, the first metal metasurface array is designed by adjusting the geometric dimensions and period of the metasurface unit, so that the first metal metasurface array forms an absorption peak at any wavelength in the near infrared. The second metal metasurface array is designed by adjusting the geometric dimensions and period of the metasurface unit, so that the second metal metasurface array forms an absorption peak at any wavelength in the mid-infrared. Based on the geometric dimensions and period of the first and second metal metasurface arrays, the corresponding photolithography mask is designed.

9. The fabrication method of the perovskite-based multipolar photodetector as described in claim 4, characterized in that, Step S5 specifically includes: Spin-coat photoresist onto a single-polished silicon oxide substrate covered with the first and second metal electrodes, and pre-bake at 90-120°C for 5-10 minutes. Align the photomask designed in step S4 with the channel of the single-polished silicon oxide substrate and expose it using electron beam direct writing. After exposure, the single-polished silicon oxide substrate is placed in the developer solution for development. After being taken out, it is rinsed with deionized water and dried with nitrogen gas. Then, the first metal metasurface array and the second metal metasurface array are vapor deposited. The evaporated single-layer polished silicon oxide substrate is immersed in acetone solvent to dissolve the photoresist. After rinsing the dissolved single-sided polished silicon oxide substrate with deionized water and ethanol, it is dried with nitrogen gas. The patterns of the first metal metasurface array and the second metal metasurface array are transferred into the channel between the first metal electrode and the second metal electrode to obtain a single-sided polished silicon oxide substrate covered with the first metal metasurface array, the second metal metasurface array, the first metal electrode and the second metal electrode.

10. The method for fabricating a perovskite-based multipolar photodetector as described in claim 4, characterized in that, Step S6 specifically includes: A single-sided polished silicon oxide substrate covered with a first metal metasurface array, a second metal metasurface array, a first metal electrode, and a second metal electrode is placed in a spin coater. A perovskite precursor solution is added dropwise for spin coating, followed by the addition of chlorobenzene as a spin coating anti-solvent. The substrate is then placed on a heating stage and annealed at 100°C for 15 minutes to form a perovskite light-absorbing and thermoelectric layer. This perovskite light-absorbing and thermoelectric layer is then brought into ohmic contact with the first and second metal electrodes to obtain a multipolar photodetector covered with a perovskite thermoelectric and light-absorbing layer.

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