Plasmon metasurface-based infrared polarized photoelectric detector and preparation method thereof

Abstract

The invention discloses an infrared polarized photoelectric detector based on a plasmon metasurface and a preparation method thereof, and belongs to the technical field of photoelectric detection. According to the photoelectric detector, coupling resonance is achieved through the bottom metal nano array and the WSe2 / InSe heterojunction, heterojunction infrared light absorption is enhanced, photocarriers are generated, and finally the photocarriers are collected by the top electrode layer to form photocurrent, so that the infrared light detection capacity of the original WSe2 / InSe heterojunction is improved. And optical absorption enhancement at different infrared wavelengths can be realized by adjusting the period, the length and the width of the metal nano array. When 4V bias voltage is applied, compared with an original WSe2 / InSe heterojunction photoelectric detector, the photoelectric responsivity of the photoelectric detector is improved by one order of magnitude, and the detection rate is improved by two orders of magnitude. In the aspect of polarization detection, the anisotropy of the nano array is utilized, and polarization insensitivity is creatively improved to the polarization ratio of 5.2.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical power sources, and in particular relates to an infrared polarization photodetector based on a plasmon metasurface and a preparation method thereof. Background Art

[0002] Heterogeneous integration of 2D layered materials in the form of van der Waals heterojunctions (vdWHs) has attracted extensive attention in research fields ranging from condensed matter physics to optoelectronics due to their intriguing properties such as twist-angle-dependent moiré excitons, ultrafast interlayer charge transfer, and strong light-matter interactions. To date, various types of 2D layered materials have been used to construct vdWHs, including graphene, transition metal dichalcogenides (TMDs), metal chalcogenides, and single-element layered materials. The band gaps of these heterojunctions can be direct or indirect, and their band gap structures vary with the number of layers of the constituent materials, providing considerable versatility and flexibility for emerging photonic and optoelectronic applications. Despite the fascinating properties brought by van der Waals heterostructures, the interlayer absorption in heterojunctions is usually weak, 3 to 4 orders of magnitude lower than the intrinsic intralayer absorption of 2D layered materials, due to the reduced electron-hole wave function overlap. To develop high-performance optoelectronic devices, it is crucial to achieve enhanced light-matter interactions in heterojunctions.

[0003] Plasmonic metastructures provide a viable solution for enhancing local electromagnetic fields. When integrated with two-dimensional materials and heterostructures, they can effectively enhance their optical processes, including PL emission, light absorption, and nonlinear processes. Zhu et al. achieved two orders of magnitude enhancement of interlayer exciton (IX) emission in WS2 / InSe heterojunctions with plasmon-mirror structures [ACS Nano. 2024, 18, 13599-13606]. Guo et al. greatly improved the light absorption of WSe2 / MoS2 heterojunctions over a wide wavelength range by adjusting gold nanoparticles [ACS Appl. Nano. Mater. 2021, 5, 587-596]. However, most previously reported metastructure / vdWH hybrid systems involve the fabrication of noble metal nanostructures on top of vdWH, which inevitably brings surface contamination and defects to two-dimensional layered materials and impairs their optical response. Moreover, at present, plasmon supersurface enhancement of local electromagnetics is only applied in optical scenarios and has not been used in the field of photoelectric detection.

[0004] Based on this, there is an urgent need to combine plasmon metasurfaces with existing two-dimensional material photodetectors in a better way, so as to expand and improve the performance of two-dimensional layered material photodetectors. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above problems and / or the problems existing in the prior art, the present invention is proposed.

[0007] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide an infrared polarization photodetector based on a plasmon metasurface.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions, including: First layer: non-transparent dielectric substrate; The second layer: metal nanoarray, stacked on the first layer of non-transparent dielectric substrate; The third layer: aluminum oxide, covering the second layer of metal nanoarray; The fourth layer: Boron nitride, completely covering the first, second and third layers; The fifth layer: a two-dimensional material heterojunction, stacked directly on top of the fourth layer of boron nitride; And the sixth layer: metal electrodes.

[0009] As a preferred solution of the infrared polarization photodetector based on plasmon metasurface described in the present invention, the metal nanoarray is periodically arranged on a non-transparent medium substrate, and adjacent nanorods with the same size and arrangement direction are polarization units.

[0010] As a preferred solution of the infrared polarization photodetector based on the plasmon metasurface of the present invention, the material of the metal nanoarray is one or more of aluminum, noble metals and transition metals, preferably one of gold, silver, copper and aluminum; The spacing L between the centers of the polarization units in the metal nanoarray X 540~700 nm; The spacing L between the centers of the polarization units in the metal nanoarray y 540~700 nm; The height range of the polarization unit in the metal nanoarray is 30-60 nm; The length and width of the nanorods constituting the polarization unit in the metal nanoarray are 90 nm and 350 nm.

[0011] As a preferred solution of the infrared polarization photodetector based on the plasmon metasurface of the present invention, wherein: the aluminum oxide completely covers the metal nanoarray; The height of the aluminum oxide is in the range of 3 to 6 nm.

[0012] As a preferred solution of the infrared polarization photodetector based on plasmon metasurface described in the present invention, wherein: the height range of the boron nitride is 5~20 nm.

[0013] As a preferred solution of the infrared polarization photodetector based on plasmon metasurface described in the present invention, the two-dimensional material heterojunction is composed of an InSe material layer and a WSe2 material layer from bottom to top.

[0014] As a preferred solution of the infrared polarization photodetector based on plasmon metasurface described in the present invention, the number of InSe material layers in the two-dimensional material heterojunction ranges from 3 to 6 layers; the number of WSe2 material layers in the two-dimensional material heterojunction ranges from 2 to 4 layers.

[0015] As a preferred solution of the infrared polarization photodetector based on plasmon metasurface described in the present invention, the working band of the photodetector is near infrared.

[0016] As a preferred solution of the infrared polarization photodetector based on plasmon metasurface described in the present invention, the operating wavelength of the photodetector is 1100~1600 nm.

[0017] Another object of the present invention is to overcome the deficiencies in the prior art and provide a method for preparing an infrared polarization photodetector based on a plasmon metasurface.

[0018] In order to solve the above technical problems, the present invention provides the following technical solutions, including: A second layer of metal nanoarray is formed on the first layer of non-transparent dielectric substrate by using focused electron beam exposure and electron beam evaporation technology; A third layer of Al2O3 is grown on the surface of the second metal nanoarray (200) by using atomic layer deposition technology; The fourth layer of boron nitride and the fifth layer of InSe / WSe2 heterojunction were directionally transferred on the third layer of Al2O3 using mechanical exfoliation and PPC / PDMS stamps; Metal electrodes were prepared on the fifth InSe / WSe2 heterojunction using focused electron beam exposure and electron beam evaporation technology.

[0019] As a preferred solution of the method for preparing the infrared polarization photodetector based on plasmon metasurface described in the present invention, wherein: the electron beam current of the focused electron beam exposure is 75 nA and the voltage is 20 KV.

[0020] As a preferred solution of the method for preparing the infrared polarization photodetector based on the plasmon metasurface of the present invention, the electron beam evaporation includes first evaporating 3 nm titanium as an adhesion layer at a rate of 0.5 Å / s, and then evaporating 40 nm gold at a rate of 0.3 Å / s. Finally, soaking in acetone for 2 h to remove the surface photoresist.

[0021] As a preferred solution of the method for preparing the infrared polarization photodetector based on plasmon metasurface described in the present invention, wherein: the atomic layer deposition technology, wherein the temperature of the atomic layer deposition is 80°C, and the growth rate is 0.4Å / r.

[0022] As a preferred solution of the method for preparing the infrared polarization photodetector based on the plasmon metasurface of the present invention, the mechanical peeling and directional transfer technology includes: Use PDMS to find a two-dimensional layered material layer of boron nitride, WSe2 and InSe with a specific thickness. The process of directional transfer is as follows: on a single-sided polished silicon wafer, spin-coat a PPC film at a speed of 1600 r / s, and stick the PPC film to a PDMS substrate to obtain a PDMS / PPC stamp. First, adhere the PPC side of the stamp to the mechanically peeled WSe2 surface, heat it at 40°C for 10s, turn off the heating, cool it to 35°C, and lift the stamp to obtain a WSe2 flake. Then adhere the PDMS / PPC stamp with the WSe2 flake to the InSe flake, heat it at 40°C for 10s, turn off the heating, cool it to 35°C, and lift the stamp to obtain a WSe2 / InSe heterojunction with an electrode position. Then, the PDMS / PPC stamp with WSe2 / InSe heterojunction was adhered to boron nitride, heated at 48 °C for 10 s, then turned off the heating, cooled to 35 °C, and the stamp was lifted to obtain the WSe2 / InSe / boron nitride heterojunction. Then, it was heated at 120 °C for 10 s and lifted while hot to ensure that the three layers of materials were simultaneously and directional transferred to the top of the second layer of metal nanoarray. Finally, after soaking in acetone for 10 min and removing the PPC film, a clean fourth layer of boron nitride and a fifth layer of WSe2 / InSe heterojunction were obtained on the non-transparent dielectric substrate covering the second layer of metal nanoarray and the third layer of aluminum oxide.

[0023] As a preferred embodiment of the method for preparing the infrared polarization photodetector based on the plasmon metasurface of the present invention, the process of the focused electron beam positioning exposure technology is as follows: spin-coating PMMA at a speed of 3000 r / s on a non-transparent dielectric substrate covering the second layer of metal nanoarray, the third layer of aluminum oxide, the fourth layer of boron nitride and the fifth layer of WSe2 / InSe heterojunction, and then spot-exposing the electrode pattern at the reserved position on the fifth layer of WSe2 and InSe. The process of the electron beam evaporation is as follows: first, evaporating 3 nm titanium as an adhesion layer at a rate of 0.2 Å / s, and then evaporating 40 nm gold at a rate of 0.3 Å / s. Finally, soaking in acetone for 2 h to remove the surface photoresist PMMA.

[0024] Beneficial effects of the present invention: By optimizing the stacking order of metal nanoarrays and two-dimensional materials, and placing the metal array below the two-dimensional layered material heterojunction, the pollution and defects caused by the metal nanoarray to the two-dimensional material can be effectively reduced. Moreover, the configuration of the two-dimensional material on top can effectively avoid the scattering of light on the surface of the metal nanoarray, and the external light field directly acts on the effective area of ​​the device, improving the utilization rate of the light source.

[0025] The periodically arranged plasmon metasurface enhances the absorption of infrared light by two-dimensional materials, and enhances the ability to convert optical signals into electrical signals, thereby achieving improved responsiveness. Compared with the original WSe2 / InSe heterojunction photodetector, the present invention has better photodetection performance.

[0026] By utilizing the strong absorption difference of periodically arranged anisotropic metal nanoarrays for infrared polarized light, the polarized light signal is converted into electrical signals of different sizes, thereby better distinguishing the angles of linear polarized light.

[0027] By optimizing the transfer method, the two-dimensional materials are stacked layer by layer in three natural bonding processes, and the three layered materials are transferred to designated positions at the same time, further improving the neatness of the contact interface between different two-dimensional material sheets. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0029] Figure 1Schematic diagram of the structure of an infrared polarization photodetector based on a plasmon metasurface prepared in Example 1, wherein (100) is a non-transparent dielectric substrate, (200) is a metal nanoarray, (300) is an aluminum oxide layer, (400) is a boron nitride layer, (500) is a heterojunction layer, and (600) is a metal electrode layer; Figure 2 The topography of the metal nanoarray in the infrared polarization photodetector based on the plasmon metasurface prepared in Example 1. The left picture is the result of the local array atomic force microscope scan, the upper right picture is the height and spacing data of each rectangular structure along the long axis direction of the rectangular structure, and the lower right picture is the height and spacing data of each rectangular structure along the short axis direction of the rectangular structure.

[0030] Figure 3 This is the simulated polarization reflection spectrum of the infrared polarization photodetector based on the plasmon metasurface prepared in Example 1.

[0031] Figure 4 This is a schematic diagram of the structure of the infrared polarization photodetector without plasmon metasurface prepared in Comparative Example 1.

[0032] Figure 5 The photoresponsivity curves of photodetectors with and without plasmon metasurface to light of different wavelengths under 4V bias.

[0033] Figure 6 The response curve of the infrared polarization photodetector based on the plasmon metasurface prepared in Example 1 to the 1100-1600 nm band with different polarization directions under a bias voltage of 4 V. DETAILED DESCRIPTION

[0034] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0035] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0036] The raw materials used in the present invention are all commercially available unless otherwise specified.

[0037] The optical and electrical properties of the materials prepared in the embodiments of the present invention were tested as follows: The spectral photocurrent measurement and photocurrent mapping were performed using a photocurrent scanning system (Metatest, Mstarter-200) provided by Nanjing Meta Photonics Technology Co., Ltd. The main instruments include a supercontinuum laser source (NKTPhotonics, SuperK EXR-15) and a semiconductor device analyzer (Keysight, B1500A). The repetition rate of the supercontinuum laser source is 78 MHz and the pulse width is 20 ps.

[0038] Example 1

[0039] This embodiment provides an infrared polarization photodetector based on a plasmon metasurface and a method for preparing the same.

[0040] Structure Figure 1 As shown, from bottom to top, it includes: Non-transparent dielectric substrate 100: a 400 μm thick highly doped silicon layer and a 300 nm thick SiO2 film layer are stacked in sequence from bottom to top; Metal nanoarray 200: spacing L between polarization unit centers X 620 nm; L y is 620 nm; the thickness of the polarization unit is 40 nm; the length and width of the nanorods constituting the polarization unit are 90 and 350 nm; Alumina 300: 5 nm thick aluminum oxide; Boron Nitride 400: 15 nm boron nitride; Two-dimensional material heterojunction 500: 2 layers of WSe2 and 5 layers of InSe; Metal Electrode 600: 3 nm titanium and 40 nm gold.

[0041] The specific preparation method is as follows: The non-transparent dielectric substrate that had been ultrasonically cleaned with acetone, ethanol, and deionized water was dried with a nitrogen gun and then spin-coated with PMMA photoresist. Then, the nanoarray pattern with specific parameters was photolithographically formed using focused electron beam exposure technology. The parameters of focused electron beam exposure were an electron beam current of 75 nA and a voltage of 20 KV.

[0042] By electron beam evaporation technology, 3 nm titanium and 40 nm gold are evaporated from bottom to top on the non-transparent dielectric substrate 100 containing the nanoarray pattern prepared in step (1). The parameters of electron beam evaporation are as follows: the target materials are titanium and gold, the titanium evaporation rate is 0.5 Å / s, the gold evaporation rate is 0.3 Å / s, and the evaporation vacuum is 5×10 -4 Then it was transferred to acetone and allowed to stand to remove the PMMA photoresist to obtain the gold nanoarray.

[0043] 15 nm boron nitride, 5 layers of InSe and 2 layers of WSe2 were obtained by mechanical exfoliation. Combined with PDMS / PPC-assisted site-directed transfer technology, boron nitride, InSe and WSe2 sheets were stacked from bottom to top directly above the gold nanoarray prepared in step (2).

[0044] The surface of the product prepared in step (3) was spin-coated with photoresist PMMA and air-dried; then, the photolithographic electrode patterns were positioned on the WSe2 and InSe thin films respectively by focused electron beam exposure technology. The parameters of focused electron beam exposure include: electron beam current of 75 nA and voltage of 20 KV.

[0045] The product prepared in step (4) was evaporated from bottom to top with 3 nm titanium and 40 nm gold by electron beam evaporation technology. The parameters of electron beam evaporation include: the target materials are titanium and gold, the titanium evaporation rate is 0.5 Å / s, the gold evaporation rate is 0.3 Å / s, and the evaporation vacuum is 5×10 -4 Pa. Then it was transferred to acetone and allowed to stand to remove the PMMA photoresist, and finally an infrared polarization photodetector based on the plasmon metasurface was obtained.

[0046] like Figure 2 As shown, the shape of the gold nanoarray is demonstrated by atomic force microscopy testing, and it is shown that the gold nanoarray prepared in Example 1 has good periodicity and the prepared size is consistent with the expected result.

[0047] like Figure 3 As shown in the figure, the infrared polarization photodetector based on the plasmon metasurface prepared in Example 1 has an obvious reflection peak in one polarization direction in the 950-1650nm infrared region, and no reflection peak in the other polarization direction. It can be seen that the photodetector can achieve polarization selective absorption in the near-infrared band. The polarization ratio of the photodetector was measured to be 5.2, the responsivity was 1.9 mA / W, and the specific detection rate was 1.8 × 10 10 Jones.

[0048] Comparative Example 1 This comparative example provides a primitive device without a metal nanoarray.

[0049] The structural diagram is as follows Figure 4 , from bottom to top include: Non-transparent dielectric substrate 100: a 400 μm thick highly doped silicon layer and a 300 nm thick SiO2 film layer are stacked in sequence from bottom to top; Boron Nitride 400: 15 nm boron nitride; Two-dimensional material heterojunction 500: 2 layers of WSe2 and 5 layers of InSe; Top metal electrode 600: 3 nm titanium and 40 nm gold.

[0050] The difference between this comparative example and Example 1 is that there is no metal nanoarray, and the rest of the preparation process is the same as that of Example 1, and an infrared polarization photodetector without a plasmon metasurface is prepared.

[0051] like Figure 5 As shown in the figure, the photoresponse curves of photodetectors with and without plasmon metasurfaces to light of different wavelengths under 4V bias, with a wavelength range of 1100 nm to 1600 nm and an interval of 10 nm. As can be seen from the figure, compared with the detector without plasmon metasurface, when the other structures and preparation methods of the detector are the same, the detector containing plasmon metasurface has better photoresponse to near-infrared light of 1100 nm to 1600 nm, and the responsivity is one order of magnitude higher, which shows that metal nanoarrays help improve the responsivity of photodetectors.

[0052] In order to better verify and illustrate the technical effect of the linear polarization photodetector of the present invention, the polarization light response of the device can be obtained by incident vertical polarization light and horizontal linear polarization light of different wavelengths.

[0053] like Figure 6 As shown in the figure, under the irradiation of vertical linear polarized light and horizontal linear polarized light, in the wavelength range of 1100-1600 nm, the responsivity of the infrared photodetector of the plasmon metasurface in two polarization directions is obtained respectively. By comparing the two, it can be found that the responsivity of the photodetector under the irradiation of vertical linear polarized light is much greater than that under the irradiation of horizontal linear polarized light, which shows that the metal nanoarray is helpful to realize the polarized light detection of the photodetector.

[0054] Example 2

[0055] The difference between this embodiment and embodiment 1 is that the distance L between the centers of the polarization units is adjusted. X The wavelength of the infrared polarization photodetector is 580 nm, and the rest of the preparation process is the same as that in Example 1 to obtain an infrared polarization photodetector.

[0056] Example 3

[0057] The difference between this embodiment and embodiment 1 is that the distance L between the centers of the polarization units is adjusted. X The wavelength of the infrared polarization photoelectric detector is 660 nm, and the rest of the preparation process is the same as that in Example 1 to obtain an infrared polarization photoelectric detector.

[0058] The optical and electrical properties of the materials obtained in Examples 2-3 were tested, and the results compared with those of Example 1 are shown in the following table.

[0059] Table 1 , As can be seen from the table above, the spacing L between the centers of the polarization units is adjusted X The performance of infrared polarization photodetectors is significantly affected by the center spacing L of the polarization units. X The change of will significantly affect the resonance peak position of the overall structure. Only when the resonance peak position of the structure is consistent with the absorption peak position of the two-dimensional material heterojunction can the best effect be achieved. According to the results in the above table, the spacing L between the centers of the polarization units in the present invention is X The best technical effect can be obtained at 620 nm.

[0060] Example 4 The difference between this embodiment and embodiment 1 is that the distance L between the centers of the polarization units is adjusted. y The wavelength of the infrared polarization photodetector is 560 nm, and the rest of the preparation process is the same as that in Example 1 to obtain an infrared polarization photodetector.

[0061] Example 5 The difference between this embodiment and embodiment 1 is that the distance L between the centers of the polarization units is adjusted. y The wavelength of the infrared polarization photodetector is 680 nm, and the rest of the preparation process is the same as that in Example 1 to obtain an infrared polarization photodetector.

[0062] The optical and electrical properties of the materials prepared in the above-mentioned Examples 4-5 were tested, and the comparison results with those in Example 1 are shown in the following table.

[0063] Table 2 , As can be seen from the table above, the spacing L between the centers of the polarization units is adjusted y The performance of infrared polarization photodetectors is significantly affected by the spacing L between the centers of the polarization units. y The change of will significantly affect the resonance peak position of the overall structure. Only when the resonance peak position of the structure is consistent with the absorption peak position of the two-dimensional material heterojunction can the best effect be achieved. According to the results in the above table, the spacing L between the centers of the polarization units in the present invention is y The best technical effect can be obtained at 620 nm.

[0064] Example 6 The difference between this embodiment and Embodiment 1 is that the number of layers of WSe2 in the two-dimensional material heterojunction is adjusted to 3 layers, and the rest of the preparation process is the same as that of Embodiment 1 to obtain an infrared polarization photodetector.

[0065] Example 7 The difference between this embodiment and Embodiment 1 is that the number of WSe2 layers in the two-dimensional material heterojunction is adjusted to 1 layer, and the rest of the preparation process is the same as that in Embodiment 1 to obtain an infrared polarization photodetector.

[0066] The optical and electrical properties of the materials prepared in the above embodiment were tested, and the comparison results with those in embodiment 1 are shown in the following table.

[0067] Table 3 , It can be seen from the above table that adjusting the number of WSe2 layers in the two-dimensional material heterojunction has a significant effect on the performance of the infrared polarization photodetector. This is because in the two-dimensional material heterojunction, the number of WSe2 layers will significantly affect the light absorption characteristics of the overall heterojunction, including changing the position and intensity of the absorption peak, so that it cannot be consistent with the resonance peak of the polarization unit and cannot achieve the best effect. According to the results in the above table, the best technical effect can be obtained when the number of WSe2 layers in the two-dimensional material heterojunction in the present invention is 2 layers.

[0068] Example 8 The difference between this embodiment and embodiment 1 is that the number of InSe layers in the two-dimensional material heterojunction is adjusted to 4 layers, and the rest of the preparation process is the same as that of embodiment 1 to obtain an infrared polarization photodetector.

[0069] Example 9 The difference between this embodiment and embodiment 1 is that the number of InSe layers in the two-dimensional material heterojunction is adjusted to 6 layers, and the rest of the preparation process is the same as that of embodiment 1 to obtain an infrared polarization photodetector.

[0070] The optical and electrical properties of the materials obtained in Examples 8-9 were tested, and the results compared with those in Example 1 are shown in the following table.

[0071] Table 4 , As can be seen from the above table, adjusting the number of InSe layers in the two-dimensional material heterojunction has a significant effect on the performance of the infrared polarization photodetector. This is because in the two-dimensional material heterojunction, the number of InSe layers will significantly affect the light absorption characteristics of the overall heterojunction, including changing the position and intensity of the absorption peak, so that it cannot be consistent with the resonance peak of the polarization unit and cannot achieve the best effect. According to the results in the above table, the best technical effect can be obtained when the number of InSe layers in the two-dimensional material heterojunction in the present invention is 6 layers.

[0072] Comparative Example 2 This comparative example provides a method for constructing a GeSe / MoS2 heterojunction photodetector by dry transfer. GeSe and MoS2 flakes are peeled off from commercial bulk crystals. In this process, the MoS2 layer is first transferred to a silicon wafer covered with a 300 nm SiO2 film. Then, the GeSe is peeled off onto a transparent polydimethylsiloxane (PDMS) film using scotch tape and aligned with the MoS2 under an optical microscope (OLYMPUS BX51). By slight pressing, the GeSe is separated from the PDMS film and stacked on the previously transferred MoS2 flakes. The Ti / Au electrodes are positioned by electron beam lithography and electron beam evaporation. The detector has a responsivity of 590 mA / W, a polarization ratio of 2.95, and a specific detectivity of 1.03 × 10 10 Jones and the detection wavelength is 532nm.

[0073] Comparative Example 3 This comparative example provides a method for preparing a PdSe2 / GaN Schottky junction device.

[0074] First, a PdSe2 layer was in situ prepared on a pre-patterned n-GaN film (resistivity: ~ 0.5 Ω·cm), and then an insulating Al2O3 film (~ 30 nm) was deposited on a portion of it by a magnetron sputtering system. Then, Ni / Au (10 / 50 nm) electrodes were evaporated on top of the PdSe2 film. The detector has a polarization ratio of 4.5, a responsivity of 249.9 mA / W, and a detection wavelength of 360 nm.

[0075] Comparative Example 4 Through mechanical exfoliation, 5 layers of InSe thin sheets and 2 layers of WSe2 thin sheets were obtained, and the InSe / WSe2 two-dimensional material heterojunction was obtained by combining PDMS / PPC assisted fixed-point transfer technology. The heterojunction was then transferred to a gold nanoarray covered with 15 nm boron nitride. The spacing L between the centers of the polarization units in the gold nanoarray is X is 750 nm; the spacing between the centers of the polarization units is L y The polarization ratio of the detector is 0, the responsivity is 0.12 mA / W, and the specific detectivity is 0.08 × 10 10 Jones.

[0076] The optical and electrical properties of the materials prepared in the above comparative example were tested, and the comparison results with those of Example 1 are shown in the following table.

[0077] Table 5 , As can be seen from the above table, a well-designed metal nanoarray can significantly enhance the photoelectric detection capability of a two-dimensional material heterojunction photodetector. At the same time, the use of anisotropic units in the metal nanoarray can give the polarization-insensitive detector the ability to detect polarized light. More importantly, the polarization detection effect given by the metal nanoarray is much better than that of the two-dimensional material heterojunction that has the ability to detect polarized light, which can be proved by the higher polarization ratio of the present invention.

[0078] In summary, the present invention optimizes the stacking order of metal nanoarrays and two-dimensional materials, and places the metal array below the heterojunction of two-dimensional layered materials, which can effectively reduce the pollution and defects caused by the metal nanoarray to the two-dimensional material. Moreover, the configuration of the two-dimensional material on top can effectively avoid the scattering of light on the surface of the metal nanoarray, and the external light field directly acts on the effective area of ​​the device, thereby improving the utilization rate of the light source. The present invention uses a periodically arranged plasmon metasurface to enhance the absorption of infrared light by two-dimensional materials, and enhances the ability to convert optical signals into electrical signals, thereby achieving an improvement in responsiveness. Compared with the original WSe2 / InSe heterojunction photodetector, the present invention has better photoelectric detection performance. The present invention also optimizes the transfer method, stacks the two-dimensional materials layer by layer in three natural bonding processes, and transfers the three layered materials to the specified position at a fixed point, further improving the neatness of the contact interface between different two-dimensional material sheets.

[0079] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. An infrared polarization photodetector based on a plasmon metasurface, characterized in that: The photodetector, include, First layer: non-transparent dielectric substrate (100); The second layer: a metal nanoarray (200), stacked on the first non-transparent medium substrate (100); The third layer: aluminum oxide (300), covering the second layer of metal nanoarray (200); The fourth layer: Boron Nitride (400), completely covering the first, second and third layers; The fifth layer: a two-dimensional material heterojunction (500), stacked directly on the fourth layer of boron nitride (400); And a sixth layer: a metal electrode (600).

2. The infrared polarization photodetector based on plasmon metasurface according to claim 1, characterized in that: The metal nanorod array (200) is periodically arranged on a non-transparent medium substrate (100), and adjacent nanorods having the same size and arrangement direction serve as polarization units.

3. The infrared polarization photodetector based on plasmon metasurface according to claim 1 or 2, characterized in that: The material of the metal nanoarray (200) is one or more of aluminum, noble metals and transition metals; The spacing L between the centers of the polarization units in the metal nanoarray (200) is X 540~700 nm; The spacing L between the centers of the polarization units in the metal nanoarray (200) is y 540~700 nm; The height range of the polarization unit in the metal nanoarray (200) is 30-60 nm; The length and width of the nanorods constituting the polarization unit in the metal nanoarray (200) are 90 nm and 350 nm respectively.

4. The infrared polarization photodetector based on plasmon metasurface according to claim 1, characterized in that: The aluminum oxide (300) completely covers the metal nanoarray (200); the height of the aluminum oxide (300) ranges from 3 to 6 nm.

5. The infrared polarization photodetector based on plasmon metasurface according to claim 1, characterized in that: The height range of the boron nitride (400) is 5-20 nm.

6. The infrared polarization photodetector based on plasmon metasurface according to claim 1, characterized in that: The two-dimensional material heterojunction (500) comprises, from bottom to top, an InSe material layer (501) and a WSe2 material layer (502).

7. The infrared polarization photodetector based on plasmon metasurface according to claim 6, characterized in that: The number of InSe material layers (501) in the two-dimensional material heterojunction (500) ranges from 3 to 6 layers; the number of WSe2 material layers (502) in the two-dimensional material heterojunction (500) ranges from 2 to 4 layers.

8. The infrared polarization photodetector based on plasmon metasurface according to claim 1, characterized in that: The working band of the photoelectric detector is near infrared.

9. The infrared polarization photodetector based on plasmon metasurface according to claim 8, characterized in that: The working wavelength of the photodetector is 1100-1600 nm.

10. The method for preparing an infrared polarization photodetector based on a plasmon metasurface according to any one of claims 1 to 2 and 4 to 9, characterized in that: include, Forming a second layer of metal nanoarray (200) on the first layer of non-transparent dielectric substrate (100) by using focused electron beam exposure and electron beam evaporation technology; Growing a third layer of Al2O3 (300) on the surface of the second layer of metal nanoarray (200) using atomic layer deposition technology; The fourth layer of boron nitride (400) and the fifth layer of InSe / WSe2 heterojunction (500) were directionally transferred on the third layer of Al2O3 (300) using mechanical exfoliation and PPC / PDMS stamp; A metal electrode (600) is prepared on the fifth InSe / WSe2 heterojunction (500) by using focused electron beam exposure and electron beam evaporation technology.

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