Polarized photoelectric detector, preparation method thereof and imaging device

Abstract

The invention discloses a polarized photoelectric detector, a preparation method thereof and an imaging device, and belongs to the technical field of polarized light detection. A photoelectric conversion layer on the substrate; the nanowire optical waveguide has a polarized light transmission characteristic and is positioned on the photoelectric conversion layer; the electrode is located on the photoelectric conversion layer, and the electrode and the nanowire optical waveguide are arranged at an interval. The electrodes are used for being connected with an external circuit, the nanowire optical waveguide serves as an optical waveguide to achieve selective transmission of polarized light, the photoelectric conversion layer serves as a photosensitive material to achieve photoelectric conversion, and photon-generated carriers generated through photoelectric conversion are transmitted to the two electrodes and guided into the external circuit to form light current. The polarized light response of the device provided by the invention comes from selective light transmission of the nanowire optical waveguide, and the polarized light response can be realized in an in-plane isotropic material. In addition, when the in-plane anisotropic material is used as the photosensitive material, the polarization ratio of the detector can be enhanced.

Description

Technical Field

[0001] The present invention relates to the field of polarized light detection technology, and in particular to a polarized photoelectric detector and a preparation method and an imaging device thereof. Background Art

[0002] Polarization photodetectors can detect the intensity, wavelength, and polarization direction of light simultaneously, which can significantly improve the imaging effect and the ability to detect objects. They are widely used in many fields. The main implementation methods of traditional polarization photodetectors include: (1) extracting the polarization information of light through polarization light path and optical structure design; (2) using the structural anisotropy of the material itself to realize the recognition of the polarization information of light. However, in recent years, with the large-scale and rapid development of artificial intelligence, big data, and smart cities, the demand for information detection and intelligent perception has increased dramatically, and it is urgent to build small-sized, modular, highly integrated polarization photodetection devices. The complex structure and large volume of traditional polarization photodetection devices have greatly reduced the integration of polarization detection systems. Therefore, polarization photodetectors based on the structural anisotropy of the light detection material itself have received widespread attention, including polarization photodetectors based on the polarization sensitivity of one-dimensional nanomaterials themselves and polarization photodetectors constructed based on the in-plane anisotropic photoelectric properties of two-dimensional materials. However, due to the limitations of device structure, material system, etc., the performance and application range of polarization photodetectors are also greatly limited.

[0003] Compared with traditional bulk optoelectronic materials, two-dimensional materials can solve the integration problem faced by photodetectors to a certain extent, and have very high theoretical photoresponsivity. In recent years, polarization detectors based on anisotropic van der Waals materials have received widespread attention and made outstanding progress. However, the types of two-dimensional materials with in-plane anisotropic optoelectronic properties are limited. Among the thousands of van der Waals materials discovered so far, only more than a dozen van der Waals materials have shown the potential for polarized light detection. The light response band and dark current of these materials are affected by their structure and energy band, which greatly limits the application of polarized light detection based on in-plane anisotropic van der Waals materials. Although in-plane isotropic van der Waals materials, such as graphene and molybdenum sulfide, which account for the vast majority of van der Waals materials, are considered to be potential light detection materials, the high symmetry of the in-plane structure of these materials means that when used for light detection, they can only respond to wavelength and light intensity, and cannot identify the polarization information of the light signal. Therefore, how to achieve polarization sensitivity (or polarization light response) of in-plane isotropic materials or further enhance the polarization ratio of detectors based on in-plane anisotropic materials is of great significance for the development of polarization-sensitive detectors based on van der Waals materials. Summary of the invention

[0004] Based on the above-mentioned deficiencies of the prior art, the object of the present invention is to provide a polarization photodetector and a preparation method and imaging device thereof, aiming to achieve the polarization light response of an in-plane isotropic material or further improve the polarization ratio of a polarization photodetector based on an in-plane anisotropic material.

[0005] The technical solution of the present invention is as follows:

[0006] A first aspect of the present invention provides a polarization photodetector, wherein the polarization photodetector comprises:

[0007] substrate;

[0008] A photoelectric conversion layer is located on the substrate;

[0009] A nanowire optical waveguide, located on the photoelectric conversion layer, wherein the nanowire optical waveguide has polarized light transmission characteristics;

[0010] The electrode is located on the photoelectric conversion layer and is spaced apart from the nanowire optical waveguide.

[0011] Optionally, the substrate includes one of a silicon and silicon oxide composite substrate, a polydimethylsiloxane substrate, a polyimide substrate, a sapphire substrate, a quartz glass substrate and a mica substrate;

[0012] The material of the electrode includes at least one of gold, platinum, chromium and copper;

[0013] The electrodes include a first electrode and a second electrode spaced apart at two sides of the nanowire optical waveguide.

[0014] Optionally, the photoelectric conversion layer includes a van der Waals material, the van der Waals material includes an in-plane isotropic van der Waals material or an in-plane anisotropic van der Waals material, and the in-plane isotropic van der Waals material includes at least one of graphene, molybdenum sulfide, lead iodide, tungsten selenide and black phosphorus.

[0015] Optionally, the material of the nanowire optical waveguide is a superlattice nanowire, and the superlattice nanowire includes lead iodide nanowires with a layered structure, and organic molecules inserted between the lead iodide nanowire layers and bonded to the lead iodide nanowires through chemical bonds.

[0016] Optionally, the organic molecule includes at least one of an acetic acid molecule, an N,N-dimethylformamide molecule and an N-methylpyrrolidone molecule.

[0017] A second aspect of the present invention provides a method for preparing a polarization photodetector, comprising the following steps:

[0018] providing a substrate;

[0019] forming a photoelectric conversion layer on the substrate;

[0020] forming a nanowire optical waveguide on the photoelectric conversion layer, wherein the nanowire optical waveguide has a polarized light transmission characteristic;

[0021] An electrode is formed on the photoelectric conversion layer, and the electrode is spaced apart from the nanowire optical waveguide to obtain the polarization photodetector.

[0022] Optionally, lead iodide powder is used as a raw material to prepare superlattice nanowires by chemical vapor deposition, and the superlattice nanowires are directionally transferred to the photoelectric conversion layer to form a nanowire optical waveguide.

[0023] Optionally, the step of preparing superlattice nanowires by chemical vapor deposition using lead iodide powder as a raw material and transferring the superlattice nanowires to the photoelectric conversion layer in a directional manner specifically includes:

[0024] Step a, placing lead iodide powder in a first zone of a double-temperature zone tubular furnace, and placing a substrate in a second zone of the double-temperature zone tubular furnace;

[0025] Step b, continuously introducing an inert gas into the dual-temperature zone tubular furnace, wherein the first zone is located upstream of the inert gas flow direction, and the second zone is located downstream of the inert gas flow direction;

[0026] Step c, setting the temperature of the first region to 400-600° C., setting the temperature of the second region to 300-500° C., performing chemical vapor deposition for 5-30 minutes, stopping the heating of the first region, setting the temperature of the second region to 350-450° C., and passing the inert gas through the organic solvent and then into the double-temperature zone tubular furnace. After 10-120 minutes, stopping ventilation and heating to form superlattice nanowires on the substrate; the superlattice nanowires include lead iodide nanowires with a layered structure, and organic molecules inserted between the lead iodide nanowire layers and chemically bonded to the lead iodide nanowires;

[0027] Step d: transferring the superlattice nanowires from the substrate to the photoelectric conversion layer through an adhesive sheet.

[0028] Optionally, in step a, the distance between the first area and the second area is 10 to 15 cm;

[0029] In step b, an inert gas is continuously introduced into the dual-temperature zone tubular furnace so that the internal pressure of the dual-temperature zone tubular furnace is maintained at 1 to 100 Torr;

[0030] In step c, the organic solvent includes at least one of acetic acid, N,N-dimethylformamide and N-methylpyrrolidone.

[0031] According to a third aspect of the present invention, an imaging device is provided, wherein the imaging device comprises the polarization photodetector of the present invention as described above or the imaging device comprises the polarization photodetector prepared by the preparation method of the present invention as described above.

[0032] Beneficial effects: The present invention provides a nanowire optical waveguide integrated polarization-sensitive photodetector with a simple structure, wherein the electrode is used to connect to an external circuit, the nanowire optical waveguide acts as an optical waveguide to realize the selective transmission of polarized light, the photoelectric conversion layer acts as a photosensitive material to realize photoelectric conversion, and the photogenerated carriers generated by the photoelectric conversion are transmitted to the two electrodes and introduced into the external circuit to form a photocurrent. The polarized light response of the device provided by the present invention originates from the selective light transmission of the nanowire optical waveguide, and the polarized light response can be realized in an in-plane isotropic material (such as an in-plane isotropic van der Waals material). In addition, when an in-plane anisotropic material (such as an in-plane anisotropic van der Waals material) is used as a photosensitive material, the polarization ratio of the detector can be enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 Schematic diagram of the structure of the polarization photodetector.

[0034] Figure 2 This is the optical morphology of the superlattice nanowires prepared in Example 1.

[0035] Figure 3 These are the SEM and EDS results of the superlattice nanowires prepared in Example 1, where (a) is the SEM image, (b) is the I element distribution map, (c) is the Pb element distribution map, (d) is the C element distribution map, (e) is the O element distribution map, and (f) is the N element distribution map.

[0036] Figure 4 This is the single crystal diffraction result of the superlattice nanowire prepared in Example 1.

[0037] Figure 5 These are graphs of the nanowire optical waveguide and its 520nm wavelength polarized light selective optical transmission characteristics in Example 1, where (a) is a real picture of the nanowire optical waveguide, and (b) is a graph of the nanowire optical waveguide's 520nm wavelength polarized light selective optical transmission characteristics.

[0038] Figure 6 This is an optical photograph of the polarization photodetector prepared in Example 2.

[0039] Figure 7 This is the light response diagram of the polarization photodetector prepared in Example 2 to polarized light with a wavelength of 520 nm.

[0040] Figure 8This is the light response diagram of the polarized photodetector prepared in Example 3 to polarized light with a wavelength of 785 nm.

[0041] Fig. 9 Schematic diagram of the optical path of the imaging system in Example 4.

[0042] Fig.10 Light imaging diagram of the polarized photodetector prepared in Example 4 at a wavelength of 1550 nm, wherein (a) is 0 degrees and (b) is 90 degrees. DETAILED DESCRIPTION

[0043] The present invention provides a polarization photodetector and a method for preparing the same and an imaging device. To make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0045] Traditional polarization photodetectors achieve polarized light response based on polarization optical elements and optical path design. The device structure is complex and the integration is low. Polarization photodetectors based on the anisotropy of low-dimensional nanomaterial structures are limited by polarization materials and have extremely limited application range. Among a large number of two-dimensional materials, most are isotropic in the plane and do not have the ability to detect polarized light. In addition, photodetectors using low-dimensional nanomaterials as photoelectric conversion materials are limited by material thickness and absorbance. Only a small part of the light can be absorbed by the photoelectric conversion material and converted into photocurrent, resulting in low efficiency of the device. Based on this, an embodiment of the present invention provides a polarization photodetector, wherein, as Figure 1 As shown, the polarization photodetector comprises:

[0046] Base 1;

[0047] A photoelectric conversion layer 2 is located on the substrate 1;

[0048] A nanowire optical waveguide 3, located on the photoelectric conversion layer 2, wherein the nanowire optical waveguide has polarized light transmission characteristics;

[0049] The electrode 4 is located on the photoelectric conversion layer 2 and spaced apart from the nanowire optical waveguide 3 .

[0050] The present invention provides a nanowire optical waveguide integrated polarization-sensitive photodetector with a simple structure, wherein an electrode is used to connect an external circuit, the nanowire optical waveguide is used as an optical waveguide to realize the selective transmission of polarized light, the photoelectric conversion layer is used as a photosensitive material to realize photoelectric conversion, and the photogenerated carriers generated by the photoelectric conversion are transmitted to two electrodes and introduced into the external circuit to form a photocurrent. The polarized light response of the device provided by the present invention originates from the selective light transmission of the nanowire optical waveguide, and the polarized light response can be realized in an in-plane isotropic material (such as an in-plane isotropic van der Waals material). In addition, when an in-plane anisotropic material (such as an in-plane anisotropic van der Waals material) is used as a photosensitive material, the polarization ratio of the detector can be enhanced.

[0051] In some embodiments, the material of the nanowire optical waveguide is a superlattice nanowire, and the superlattice nanowire (i.e., superlattice organic molecule intercalated lead iodide) includes lead iodide nanowires with a layered structure, and organic molecules inserted between the lead iodide nanowire layers and bonded to the lead iodide nanowires through chemical bonds (such as Pb-O bonds).

[0052] The superlattice nanowire has a large band gap and no obvious absorption in the ultraviolet-near infrared band, making it a good optical waveguide material. In addition, the superlattice nanowire is anisotropic. When polarized light with different polarization directions is coupled into the superlattice nanowire, the intensity of the polarized light output from the end of the superlattice nanowire will change.

[0053] In some embodiments, the organic molecule includes at least one of an acetic acid molecule, an N,N-dimethylformamide (DMF) molecule, and an N-methylpyrrolidone (NMP) molecule.

[0054] In some embodiments, the substrate includes one of a silicon and silicon oxide composite substrate (i.e., a stacked silicon layer and a silicon oxide layer), a polydimethylsiloxane substrate, a polyimide substrate, a sapphire substrate, a quartz glass substrate, and a mica substrate, but is not limited thereto.

[0055] In some embodiments, the photoelectric conversion layer includes a photoelectric conversion material without polarization light response or a photoelectric conversion material with polarization light response, the photoelectric conversion material without polarization light response includes an in-plane isotropic photoelectric conversion material, and the photoelectric conversion material with polarization light response includes an in-plane anisotropic photoelectric conversion material.

[0056] In some specific embodiments, the photoelectric conversion layer includes an in-plane isotropic van der Waals material or an in-plane anisotropic van der Waals material, and the in-plane isotropic van der Waals material includes at least one of graphene, molybdenum sulfide (specifically molybdenum sulfide two-dimensional nanosheets), lead iodide (specifically lead iodide two-dimensional nanosheets), tungsten selenide (specifically tungsten selenide two-dimensional nanosheets) and black phosphorus (specifically black phosphorus two-dimensional nanosheets), but is not limited thereto. Although the in-plane isotropic van der Waals material has no difference in absorption of different polarized light, and the photocurrent does not have polarization-sensitive characteristics, after integrating the nanowire optical waveguide on the photodetector, the output light intensity has polarization-dependent characteristics after the polarized light is transmitted through the nanowire optical waveguide, so that the in-plane isotropic van der Waals material can generate polarization-sensitive photocurrent.

[0057] In some embodiments, the material of the electrode includes at least one of gold, platinum, chromium and copper, but is not limited thereto;

[0058] The electrodes include a first electrode and a second electrode spaced apart on both sides of the nanowire optical waveguide, and materials of the first electrode and the second electrode include at least one of gold, platinum, chromium and copper, but are not limited thereto.

[0059] The present invention also provides a method for preparing a polarization photodetector, which comprises the following steps:

[0060] S1. providing a substrate;

[0061] S2, forming a photoelectric conversion layer on the substrate;

[0062] S3, forming a nanowire optical waveguide on the photoelectric conversion layer, wherein the nanowire optical waveguide has polarized light transmission characteristics;

[0063] S4. Forming an electrode on the photoelectric conversion layer, wherein the electrode is spaced apart from the nanowire optical waveguide.

[0064] In step S1, the selection of the substrate can be referred to as described above and will not be repeated here.

[0065] In step S2, the material of the photoelectric conversion layer can be referred to as described above and will not be described in detail here.

[0066] In step S3, in some embodiments, lead iodide powder is used as a raw material to prepare superlattice nanowires by chemical vapor deposition, and the superlattice nanowires are directionally transferred to the photoelectric conversion layer to form a nanowire optical waveguide.

[0067] The present invention prepares superlattice nanowires by chemical vapor deposition, and the process is simple. Of course, other methods (such as solution method) can also be used to prepare superlattice nanowires.

[0068] In some embodiments, lead iodide powder is used as a raw material to prepare superlattice nanowires by chemical vapor deposition, and the step of directionally transferring the superlattice nanowires to the photoelectric conversion layer specifically includes:

[0069] Step a, placing lead iodide powder (for example, 20 to 500 mg of lead iodide powder, but not limited thereto, the amount can be selected according to actual needs) in a first area of ​​a double-temperature zone tubular furnace, and placing a substrate (for example, a mica sheet) in a second area of ​​the double-temperature zone tubular furnace; wherein the distance between the first area and the second area is 10 to 15 cm;

[0070] Step b, continuously introducing an inert gas (such as nitrogen or argon) into the dual-temperature zone tubular furnace so that the internal pressure of the dual-temperature zone tubular furnace is maintained at 1 to 100 Torr (for example, 1 Torr, 2 Torr, 5 Torr, 10 Torr, 20 Torr, 30 Torr, 40 Torr, 50 Torr, 60 Torr, 70 Torr, 80 Torr, 90 Torr or 100 Torr, etc.), the first area is located upstream of the inert gas flow direction, and the second area is located downstream of the inert gas flow direction;

[0071] Step c, setting the temperature of the first region to 400-600° C. (for example, 400° C., 450° C., 500° C., 550° C. or 600° C., etc.), setting the temperature of the second region to 300-500° C., performing chemical vapor deposition for 5-30 min (for example, 5 min, 10 min, 15 min, 20 min, 25 min or 30 min, etc.), stopping the heating of the first region, setting the temperature of the second region to 350-450° C., and passing the inert gas through an organic solvent (the organic solvent includes at least one of acetic acid, DMF and NMP) and then passing it into a double-temperature zone tubular furnace. After 10-120 min, stopping ventilation and heating to form superlattice nanowires on the substrate; the superlattice nanowires include lead iodide nanowires having a layered structure, and organic molecules inserted between the lead iodide nanowire layers and bonded to the lead iodide nanowires through chemical bonds;

[0072] Step d: transferring the superlattice nanowires from the substrate to the photoelectric conversion layer through an adhesive sheet (such as a polydimethylsiloxane (PDMS) sheet).

[0073] A third aspect of the present invention provides an imaging device, wherein the imaging device comprises the polarization photodetector of the present invention as described above or the polarization photodetector prepared by the preparation method of the present invention as described above.

[0074] The present invention will be further described below by means of specific examples.

[0075] Example 1

[0076] This embodiment provides a method for preparing a superlattice nanowire, comprising the following steps:

[0077] (1) Weighing 50 g of lead iodide powder and placing it in zone 1 of a dual-temperature zone tube furnace as a raw material for growing superlattice nanowires;

[0078] The mica sheet was placed in zone 2 of the dual-temperature zone tube furnace, with the distance between zone 1 and zone 2 being 15 cm.

[0079] (2) Use a vacuum pump to evacuate the tube furnace to a vacuum state to completely remove moisture, oxygen, etc., and then introduce nitrogen. By controlling the nitrogen flow rate, the internal pressure of the tube furnace is maintained at 50 Torr.

[0080] (3) The temperature of area 1 where the lead iodide powder is located is set to 500° C., and the temperature of area 2 where the mica sheet is located is set to 350° C. The tube furnace is heated, and the heating time is set to 10 min.

[0081] (4) After the temperature of the tube furnace reaches the set temperature, the set temperature is maintained for 20 minutes to grow the superlattice nanowires, and then the heating of area 1 is stopped, and area 2 is still maintained at 350°C.

[0082] (5) Through gas line control, nitrogen is first passed through a gas cylinder containing DMF and then enters a dual-temperature zone tubular furnace to maintain the temperature of zone 2 where the mica sheet is located at 350° C. After keeping the temperature for 20 minutes, ventilation and heating are stopped.

[0083] (6) After the dual-temperature zone tube furnace is cooled to room temperature, the mica sheet is taken out, and superlattice nanowires (i.e., superlattice DMF-intercalated lead iodide nanowires) are formed on the surface of the mica sheet.

[0084] The optical morphology of the superlattice nanowire is as follows Figure 2 As shown, the scanning electron microscope (SEM) and energy spectrum (EDS) images of the cross section of the superlattice nanowire are as follows Figure 3 As shown in FIG. 1 , it can be seen that carbon, oxygen and nitrogen elements (derived from DMF) are present, indicating that DMF molecules are inserted between the lead iodide nanowire layers. The single crystal diffraction results of the superlattice nanowire are shown in FIG. Figure 4 As shown, it can be seen that the organic molecule DMF molecule is inserted into the lead iodide nanowire layer, and the two are combined through the Pb-O bond.

[0085] The superlattice nanowire is used as a nanowire optical waveguide and its 520nm wavelength polarized light selective optical transmission characteristics are shown in the figure Figure 5 As shown, it can be seen that the superlattice nanowire has polarization-selective optical transmission characteristics.

[0086] Example 2

[0087] This embodiment provides a method for preparing a polarization photodetector, such as Figure 6 As shown, the following steps are included:

[0088] Providing a quartz glass substrate 11;

[0089] Placing the lead iodide two-dimensional nanosheet 21 on a quartz glass substrate 11;

[0090] The metal electrode is deposited on the surface of the lead iodide two-dimensional nanosheet by using directional transfer and micro-nano processing technology. Specifically, a layer of photoresist film is evenly spin-coated on the quartz glass substrate 11 with the lead iodide two-dimensional nanosheet 21 on the surface, and a photolithography method of ultraviolet exposure is used to construct the following structure on the surface of the film: Figure 6 The electrode pattern shown is developed and the resist is removed to expose the area where the electrode needs to be deposited.

[0091] On the exposed surface of the lead iodide two-dimensional nanosheet, a layer of Au is deposited by electron beam evaporation to form a first electrode 41 and a second electrode 42, and the photoresist is removed by cleaning with acetone;

[0092] A PDMS sheet is pasted on the surface of the mica sheet having the superlattice DMF intercalated lead iodide nanowires on the surface obtained in Example 1, and the superlattice DMF intercalated lead iodide nanowires on the surface of the mica sheet are peeled off by electrostatic adsorption force, so that the superlattice DMF intercalated lead iodide nanowires remain on the PDMS sheet;

[0093] By using the directional transfer technology, the superlattice DMF intercalated lead iodide nanowires 31 on the surface of the PDMS sheet are transferred to the above-mentioned lead iodide two-dimensional nanosheet and located between the first electrode 41 and the second electrode 42 to obtain a polarized photodetector.

[0094] The light response of the polarized photodetector prepared in Example 2 to polarized light of 520 nm wavelength is shown in FIG. Figure 7 shown.

[0095] If the detector does not contain DMF-intercalated lead iodide nanowires, it will not have polarized light response.

[0096] Example 3

[0097] This embodiment provides a method for preparing a polarization photodetector, which is different from Embodiment 2 only in that the lead iodide two-dimensional nanosheets are replaced by tungsten selenide two-dimensional nanosheets.

[0098] The light response of the polarized photodetector prepared in Example 3 to polarized light of 785 nm wavelength is shown in FIG. Figure 8 shown.

[0099] If the detector does not contain DMF-intercalated lead iodide nanowires, it will not have polarized light response.

[0100] Example 4

[0101] This embodiment provides a method for preparing a polarization photodetector, which is different from Embodiment 2 only in that the lead iodide two-dimensional nanosheets are replaced by black phosphorus two-dimensional nanosheets.

[0102] Use Fig. 9 The imaging system described above, wherein the polarization photodetector forms an imaging image of polarized light at a wavelength of 1550nm as shown in FIG. Fig.10 shown.

[0103] If the detector does not contain DMF-intercalated lead iodide nanowires, it will not have polarized light response.

[0104] In summary, the present invention provides a nanowire optical waveguide integrated polarization-sensitive photodetector with a simple structure, wherein the electrode is used to connect to an external circuit, the nanowire optical waveguide is used as an optical waveguide to realize the selective transmission of polarized light, the photoelectric conversion layer is used as a photosensitive material to realize photoelectric conversion, and the photogenerated carriers generated by the photoelectric conversion are transmitted to the two electrodes and introduced into the external circuit to form a photocurrent. The polarized light response of the device provided by the present invention originates from the selective light transmission of the nanowire optical waveguide, and the polarized light response can be realized in an in-plane isotropic van der Waals material. In addition, when an in-plane anisotropic van der Waals material is used as a photosensitive material, the polarization ratio of the detector can be enhanced.

[0105] It should be understood that the application of the present invention is not limited to the above examples. For ordinary technicians in this field, improvements or changes can be made based on the above description. All these improvements and changes should fall within the scope of protection of the claims attached to the present invention.

Claims

1. A polarization photodetector, characterized in that: The polarization photodetector comprises: substrate; A photoelectric conversion layer is located on the substrate; A nanowire optical waveguide, located on the photoelectric conversion layer, wherein the nanowire optical waveguide has polarized light transmission characteristics; The electrode is located on the photoelectric conversion layer and is spaced apart from the nanowire optical waveguide.

2. The polarization photodetector according to claim 1, characterized in that: The substrate includes one of a silicon and silicon oxide composite substrate, a polydimethylsiloxane substrate, a polyimide substrate, a sapphire substrate, a quartz glass substrate and a mica substrate; The material of the electrode includes at least one of gold, platinum, chromium and copper; the electrode includes a first electrode and a second electrode spaced apart at both sides of the nanowire optical waveguide.

3. The polarization photodetector according to claim 1, characterized in that: The photoelectric conversion layer includes a van der Waals material, the van der Waals material includes an in-plane isotropic van der Waals material or an in-plane anisotropic van der Waals material, and the in-plane isotropic van der Waals material includes at least one of graphene, molybdenum sulfide, lead iodide, tungsten selenide and black phosphorus.

4. The polarization photodetector according to claim 1, characterized in that: The material of the nanowire optical waveguide is a superlattice nanowire, which includes a lead iodide nanowire with a layered structure and an organic molecule inserted between the lead iodide nanowire layers and combined with the lead iodide nanowire through a chemical bond.

5. The polarization photodetector according to claim 4, characterized in that: The organic molecule includes at least one of an acetic acid molecule, an N,N-dimethylformamide molecule and an N-methylpyrrolidone molecule.

6. A method for preparing a polarization photodetector, characterized in that: The steps include: providing a substrate; forming a photoelectric conversion layer on the substrate; forming a nanowire optical waveguide on the photoelectric conversion layer; the nanowire optical waveguide has polarized light transmission characteristics; An electrode is formed on the photoelectric conversion layer, and the electrode is spaced apart from the nanowire optical waveguide to obtain the polarization photodetector.

7. The preparation method according to claim 6, characterized in that: Lead iodide powder is used as a raw material to prepare superlattice nanowires by chemical vapor deposition, and the superlattice nanowires are directionally transferred to a photoelectric conversion layer to form a nanowire optical waveguide.

8. The preparation method according to claim 7, characterized in that: The steps of preparing superlattice nanowires by chemical vapor deposition using lead iodide powder as a raw material and transferring the superlattice nanowires to the photoelectric conversion layer in a directional manner specifically include: Step a, placing lead iodide powder in a first zone of a double-temperature zone tubular furnace, and placing a substrate in a second zone of the double-temperature zone tubular furnace; Step b, continuously introducing an inert gas into the dual-temperature zone tubular furnace, wherein the first zone is located upstream of the inert gas flow direction, and the second zone is located downstream of the inert gas flow direction; Step c, setting the temperature of the first region to 400-600° C., setting the temperature of the second region to 300-500° C., performing chemical vapor deposition for 5-30 minutes, stopping the heating of the first region, setting the temperature of the second region to 350-450° C., and passing the inert gas through the organic solvent and then into the double-temperature zone tubular furnace. After 10-120 minutes, stopping ventilation and heating to form superlattice nanowires on the substrate; the superlattice nanowires include lead iodide nanowires with a layered structure, and organic molecules inserted between the lead iodide nanowire layers and chemically bonded to the lead iodide nanowires; Step d: transferring the superlattice nanowires from the substrate to the photoelectric conversion layer through an adhesive sheet.

9. The preparation method according to claim 8, characterized in that: In step a, the distance between the first area and the second area is 10 to 15 cm; In step b, an inert gas is continuously introduced into the dual-temperature zone tubular furnace so that the internal pressure of the dual-temperature zone tubular furnace is maintained at 1 to 100 Torr; In step c, the organic solvent includes at least one of acetic acid, N,N-dimethylformamide and N-methylpyrrolidone.

10. An imaging device, characterized in that: The imaging device comprises the polarization photodetector according to any one of claims 1 to 5, or the imaging device comprises the polarization photodetector prepared by the preparation method according to any one of claims 6 to 9.

Images