A two-dimensional Te / ReSe2 variable angle heterojunction photodetector and its preparation method and application

Abstract

The present invention discloses a two-dimensional Te / ReSe2 variable-angle heterojunction photodetector and its preparation method and application, belonging to the technical field of semiconductor devices. The two-dimensional Te / ReSe2 variable-angle heterojunction photodetector comprises an Si / SiO2 substrate, a Te layer, and a ReSe2 layer from bottom to top. Among them, the ReSe2 layer forms van der Waals heterojunctions with different angles with the Te layer. The present invention realizes the customization of the functions of the photodetector through methods such as CVD method, PMMA wet transfer, PVA dry transfer, photolithography gold plating, and high-temperature annealing treatment, and obtains a multi-angle heterojunction device with rich polarization characteristics. Based on the different polarization-sensitive characteristics of the device, functions such as simultaneous detection of the polarization direction and intensity of incident light, encryption and decryption, and polarization imaging can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor devices, and in particular relates to a two-dimensional Te / ReSe2 variable-angle heterojunction photoelectric detector and a preparation method and application thereof. Background Art

[0002] With the rapid development of modern optical technology, the demand for accurate measurement of light is growing, especially in the fields of communication, imaging and sensing. Polarized light is a light wave that carries polarization direction information, and its measurement is crucial to understanding and controlling the propagation characteristics of light. Traditional photodetectors can only measure the intensity of light but cannot directly obtain polarization information, which limits their application in high-precision optical measurements.

[0003] In existing technologies, the measurement of polarized light usually requires complex optical systems, such as wave plates and polarization beam splitters. These devices are not only expensive, but also bulky, difficult to integrate, and have poor portability. In addition, these systems can often only measure the polarization state of light, but cannot simultaneously obtain the intensity information of light, which is inadequate in scenarios where both polarization and intensity of light need to be analyzed simultaneously.

[0004] To overcome these limitations, researchers have been exploring new photodetectors that can simultaneously detect the angle and intensity of polarized light. Such detectors can provide more comprehensive light information, which is of great significance for improving the performance of optical systems and expanding their application range. However, existing solutions still face challenges in terms of sensitivity, response speed, cost and integration. Summary of the invention

[0005] In response to the above technical problems, the present invention proposes a two-dimensional Te / ReSe2 variable angle heterojunction photodetector and its preparation method and application. The photodetector can simultaneously measure the angle and intensity of polarized light, and has the characteristics of high sensitivity, fast response and low cost. And based on its polarized light sensitivity, it can also be applied to encryption and decryption communications and polarization imaging. By utilizing the unique properties of two-dimensional materials, the present invention is expected to achieve efficient detection of polarized light and promote the development of photodetector technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the purposes of the present invention is to provide a two-dimensional Te / ReSe2 variable-angle heterojunction photodetector, which comprises, from bottom to top, a Si / SiO2 substrate, a Te layer and a ReSe2 layer, wherein the ReSe2 layer and the Te layer simultaneously form van der Waals heterojunctions at different angles.

[0008] Two-dimensional layered materials have unique electrical and optical properties. The layers of these materials are bonded by strong chemical bonds, and the layers are coupled by relatively weak van der Waals forces, so they can be easily peeled off or added layer by layer. In addition, there are many anisotropic materials in two-dimensional materials, which have polarization-sensitive properties. The present invention uses two-dimensional layered materials ReSe2 and two-dimensional layered materials Te with polarized light response, and cleverly forms van der Waals heterojunctions of different angles between the upper layer ReSe2 material and the lower layer Te material.

[0009] Furthermore, the electrode on the Te layer is connected to a drain electrode; and / or

[0010] The electrode on the ReSe2 layer is connected to the source electrode; and / or

[0011] The angle is 0-90°; and / or

[0012] The number of the ReSe2 layers is 3 or more; and / or

[0013] The Te layer has a thickness of 40-100 nm, a width of 10-30 μm, and a length of 60-200 μm; and / or

[0014] The ReSe2 layer has a thickness of 40-100 nm, a width of 10-40 μm, and a length of 40-120 μm.

[0015] The second object of the present invention is to provide a method for preparing a two-dimensional Te / ReSe2 variable angle heterojunction photodetector, comprising the following steps:

[0016] The Te material was grown on a mica substrate using chemical vapor deposition (CVD), and then transferred to a Si / SiO2 substrate using a polymethyl methacrylate (PMMA) wet transfer method.

[0017] The ReSe2 material was adhered to another Si / SiO2 substrate by mechanical stripping, and then the ReSe2 material adhered to the Si / SiO2 substrate was transferred to the Si / SiO2 substrate containing Te material at different angles and in different sequences by polyvinyl alcohol (PVA) dry transfer method, thus preparing Te / ReSe2 heterojunction structures with different contact angles.

[0018] The required electrode pattern is prepared on a Si / SiO2 substrate containing a Te / ReSe2 heterojunction structure through maskless lithography and development, and then metal is evaporated on the obtained electrode pattern mask to form an electrode; the photoresist is removed with acetone, and vacuum high-temperature annealing is performed to obtain a Te / ReSe2 device with different contact angles, namely a two-dimensional Te / ReSe2 variable-angle heterojunction photodetector.

[0019] Furthermore, in the process of growing Te material on mica substrate by chemical vapor deposition, In2Te3 powder is used as raw material, mica is used as carrier, carrier gas is Ar / N2 mixed gas, the equipment is a high-temperature tube furnace, and the specific process parameters are: in the first stage, the temperature is increased from room temperature to 720-750°C after 35 minutes, and the carrier gas flow rate is 90-100sccm; in the second stage, it is kept at 720-750°C for 15 minutes, and the carrier gas flow rate is 90-100sccm; in the third stage, it is naturally cooled to room temperature, and the gas flow is adjusted to 30-40sccm before it drops to 100°C, and the carrier gas is turned off when it drops below 100°C.

[0020] Furthermore, the specific operating steps of the polyvinyl alcohol dry transfer method include: dropping a polyvinyl alcohol solution on a polydimethylsiloxane (PMDS) film, drying at 55-70°C for 5-10 minutes, and forming a layer of solidified polyvinyl alcohol film on the polydimethylsiloxane film; and transferring the ReSe2 material to the Te material using the polyvinyl alcohol film through a transfer platform to form a heterojunction.

[0021] Furthermore, the specific preparation steps of the electrode pattern include: spin coating the photoresist using a photoresist spreader, heating on a hot plate at 100-105°C for 3-6 minutes, and exposing; the specific process parameters are: the scanning speed of the photolithography machine is 0.06-0.5mm / s, the power is 6-19mW, the developer concentration is 3-6% tetramethylammonium hydroxide aqueous solution, and the development time is 18-25s.

[0022] Furthermore, the metal evaporation refers to evaporation of Ti / Au to form electrodes.

[0023] Furthermore, the conditions of the high temperature annealing are: temperature 100-200° C., atmosphere Ar / N 2 mixed gas, and time 30-120 min.

[0024] A third object of the present invention is to provide a two-dimensional Te / ReSe2 variable-angle heterojunction photodetector for use in a polarization-sensitive photodetector.

[0025] Compared with the prior art, the present invention has the following advantages and technical effects:

[0026] The present invention prepares high-quality Te material with controllable thickness by a CVD method. The preparation process is simple and controllable, which is conducive to mass production and promotion.

[0027] The heterojunction device disclosed in the present invention sequentially arranges a Te layer (lower layer) and a ReSe2 layer (upper layer) on a conductive substrate from bottom to top, wherein the top layer material ReSe2 with polarization sensitivity is used to absorb photogenerated carriers and is constructed into a multi-angle heterojunction device with the bottom layer Te material with anisotropy. Based on the different polarization sensitivity characteristics of the device, the functions of simultaneous detection, encryption and decryption, and polarization imaging of the polarization direction and intensity of the incident light can be realized. In addition, the device has good rectifying behavior and a wide spectral response, with a spectral response range of 405-1000nm. At the same time, the preparation is simple, the technology is mature, the equipment is easily available, and the cost is low, which is suitable for commercial promotion.

[0028] Compared with the traditional method of constructing heterojunction devices, this structure forms devices with different contact angles with the Te layer at different angles, aligning or deviating the anisotropic crystal orientation, and integrating the anisotropic photon absorption and photocarrier extraction, thereby achieving different responses to polarized light at a fixed angle.

[0029] (4) The Te / ReSe2 heterostructure has a type II band arrangement with reverse band bending, which promotes the rapid and efficient separation of photocarriers and forms a fast response time. Combining the response characteristics of multiple devices, precise synchronous detection of polarized light angle and intensity can be achieved, and encrypted communication and polarization imaging can also be realized. This invention not only introduces a reliable and promising method to develop simplified and miniaturized polarization-sensitive photodetectors, but also provides a new idea for potential applications in the next generation of ultra-compact optoelectronic systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0031] Figure 1 The planar structure diagram of the two-dimensional Te / ReSe2 variable angle heterojunction photodetector prepared in Example 1, wherein the angles between ReSe2 and Te are 0°, 30°, 60°, and 90°, S1-S4 are source electrodes, and D is a drain electrode;

[0032] Figure 2 This is an optical image of the two-dimensional Te / ReSe2 variable-angle heterojunction photodetector prepared in Example 1, where the angles between ReSe2 and Te are 0°, 30°, 60°, and 90°, S1-S4 are source electrodes, and D is a drain electrode;

[0033] Figure 3 This is the Raman graph of the two-dimensional Te / ReSe2 variable angle heterojunction photodetector prepared in Example 1;

[0034] Figure 4 Polarization Raman graphs of the two-dimensional Te / ReSe2 variable-angle heterojunction photodetector prepared in Example 1; wherein (A) is the polarization Raman graph of ReSe2; (B) is the polarization Raman graph of Te;

[0035] Figure 5 The polarization performance test diagram of the two-dimensional Te / ReSe2 variable angle heterojunction photodetector prepared in Example 1, wherein (AD) polarization light response diagram of S1-S4 devices under 808 nm light, (EH) fitting diagram of the angle-dependent device current value extracted from (AD), (IL) polar coordinate diagram of normalized photocurrent changing with polarization angle;

[0036] Figure 6 This is the wide spectrum response graph of the two-dimensional Te / ReSe2 variable-angle heterojunction photodetector prepared in Example 1. DETAILED DESCRIPTION

[0037] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0038] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0039] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0040] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0041] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0042] The present invention realizes customization of the photodetector function through methods such as CVD method, PMMA wet transfer, PVA dry transfer, photolithography gold plating, high temperature annealing treatment, etc. That is, Te is transferred to Si / SiO2 through CVD method and PMMA wet transfer, and then multi-angle in-situ heterojunction is constructed on the Si / SiO2 substrate through PVA dry transfer, and finally Ti / Au electrodes are prepared by photolithography, metal evaporation, and high temperature annealing treatment to obtain a multi-angle heterojunction device with rich polarization characteristics.

[0043] The specific technical solution includes the following steps:

[0044] (1) Te material was grown on a mica substrate using chemical vapor deposition (CVD), and then the Te material was transferred to a Si / SiO2 substrate using a polymethyl methacrylate (PMMA) wet transfer method;

[0045] (2) Select the ReSe2 single crystal material, adhere the ReSe2 material to a new Si / SiO2 substrate by mechanical exfoliation, and then use the polyvinyl alcohol (PVA) dry transfer method to transfer the ReSe2 material adhered to the Si / SiO2 substrate to the Si / SiO2 substrate containing Te material at different angles and in different sequences to build multiple heterojunctions at different angles; wherein, the Te layer and ReSe2 layers at different angles are formed on the Si / SiO2 substrate from bottom to top;

[0046] (3) forming an electrode pattern on the substrate by photolithography and development, that is, forming electrode patterns on the Te layer and the ReSe2 layers at different angles respectively;

[0047] (4) evaporating metal on the electrode pattern mask to form electrodes on the Te layer and the ReSe2 layer at different angles, and removing the photoresist with acetone;

[0048] (5) The electrodes are subjected to high-temperature annealing treatment to make the contact between the two electrodes and the materials more stable and to fully dry the device, thereby obtaining a Te / ReSe2 device with different contact angles, namely a two-dimensional Te / ReSe2 variable-angle heterojunction photodetector.

[0049] In the following embodiments of the present invention, in step (1), during the chemical vapor deposition process, In2Te3 powder is used as raw material, mica is used as carrier, the carrier gas is Ar / N2 mixed gas, the equipment is a high-temperature tube furnace, and the specific process parameters are: in the first stage, the temperature is raised from room temperature to 720-750°C in 35 minutes, and the carrier gas flow rate is 90-100sccm; in the second stage, the temperature is kept at 720-750°C for 15 minutes, and the carrier gas flow rate is 90-100sccm; in the third stage, the temperature is naturally cooled to room temperature, and the gas flow is adjusted to 30-40sccm before it drops to 100°C, and the carrier gas is turned off when it drops below 100°C. Illustratively, in the following embodiments of the present invention, specific process parameters can be selected: in the first stage, the temperature is raised from room temperature to 720°C after 35 minutes, and the carrier gas flow rate is 90 sccm; in the second stage, the temperature is kept at 720°C for 15 minutes, and the carrier gas flow rate is 90 sccm; in the third stage, the temperature is naturally cooled to room temperature, and the gas flow is adjusted to 30 sccm before it drops to 100°C, and the carrier gas is turned off when it drops below 100°C.

[0050] In the following embodiments of the present invention, in step (2), the specific operation steps of the polyvinyl alcohol dry transfer method include: dropping a polyvinyl alcohol solution on a polydimethylsiloxane (PMDS) film, drying at 55-70°C for 5-10 minutes (exemplarily, in the following embodiments of the present invention, drying at 60°C for 8 minutes) to form a layer of solidified polyvinyl alcohol film on the polydimethylsiloxane film; and transferring the ReSe2 material to the Te material using the polyvinyl alcohol film via a transfer platform to form a heterojunction.

[0051] In the following embodiments of the present invention, in step (3), the specific preparation steps of the electrode pattern include: using a coating machine to spin-coat the Te layer and the ReSe2 layer with photoresist, and then heating at a hot plate of 100-105°C for 3-6 minutes, and exposing; the specific process parameters are: the scanning speed of the photolithography machine is 0.06-0.5 mm / s, the power is 6-19 mW, the developer concentration is 3-6% tetramethylammonium hydroxide aqueous solution, and the development time is 18-25 seconds to obtain the electrode pattern. Exemplarily, in the following embodiments of the present invention, the specific process parameters can be selected as: the scanning speed of the photolithography machine is 0.3 mm / s, the power is 19 mW, the developer concentration is 4% tetramethylammonium hydroxide aqueous solution, and the development time is 19 seconds to obtain the electrode pattern.

[0052] In the following embodiments of the present invention, in step (3), the different angles can be selected from 0-90°. For example, in the following embodiments of the present invention, the different angles can be selected from 0°, 30°, 60° or 90°. The combination of different angles determines how many groups of ReSe2 materials are used. Therefore, considering the effect, in the following embodiments of the present invention, it is appropriate to select 4 groups of ReSe2 materials, which form heterojunctions with the Te layer at 0°, 30°, 60°, and 90° respectively.

[0053] In the following embodiments of the present invention, in step (4), the evaporated metal refers to the evaporated Ti / Au metal, the Ti layer is in contact with the insulating dielectric layer SiO2, and the thickness can be 10-50 nm, such as 10 nm; the thickness of the Au layer can be 50-100 nm, such as 100 nm, and electrodes are formed on the Te layer and the ReSe2 layer at different angles respectively.

[0054] In the following embodiments of the present invention, in step (5), the conditions of the high temperature annealing are: temperature 100-200°C, atmosphere Ar / N2 mixed gas, time 30-120 min. Exemplarily, in the following embodiments of the present invention, the annealing can be selected to be annealing at 150°C for 120 min.

[0055] The electrode on the Te layer can be connected to the source electrode or the drain electrode, and the electrode on the ReSe2 layer can be connected to the source electrode or the drain electrode. Exemplarily, in the following embodiments of the present invention, the electrode on the Te layer is selectively connected to the drain electrode, and the electrode on the ReSe2 layer is selectively connected to the source electrode. Between the source electrode and the drain electrode is the device junction region.

[0056] A two-dimensional Te / ReSe2 variable angle heterojunction photodetector can be prepared by the above preparation method. In the detector, the thickness of the Te layer is 40-100nm, such as 73 nm; the width is 10-30μm, such as 29 μm; the length is 60-400μm, such as 291 μm; the thickness of the ReSe2 layer is 40-100nm, such as 75 nm; the width is 10-40μm, such as 14 μm; the length is 40-120 μm, such as 45 μm. The ReSe2 layer can also be replaced by other semiconductors with polarization response characteristics such as ReS2 and GeSe.

[0057] Unless otherwise specified, the "normal temperature" and "room temperature" mentioned in the present invention refer to 20-30°C.

[0058] The raw materials used in the present invention are all purchased from the market.

[0059] The technical solution of the present invention is further illustrated by the following embodiments. Example

[0060] A method for preparing a two-dimensional Te / ReSe2 variable angle heterojunction photodetector comprises the following steps:

[0061] (1) In2Te3 powder was used as raw material, mica was used as carrier, Ar / N2 was used as carrier gas, and chemical vapor deposition (CVD) was used to deposit In2Te3 powder on the mica carrier in a high-temperature tube furnace, so that a Te layer material was grown on the mica carrier. The thickness of the formed Te layer was 73 nm, the width was 29 μm, and the length was 291 μm. The temperature control method during the deposition process was:

[0062] The first stage: from room temperature to 720°C in 35 minutes, with a carrier gas flow rate of 90 sccm;

[0063] The second stage: keep at 720℃ for 15min, with a carrier gas flow rate of 90sccm;

[0064] The third stage: naturally cool down to room temperature, adjust the gas flow to 30 sccm before it drops to 100°C, and turn off the carrier gas when it drops below 100°C;

[0065] (2) The Te layer material on the mica carrier is wet-transferred to the Si / SiO2 substrate using polymethyl methacrylate (PMMA). The Te layer formed on the Si / SiO2 substrate is specifically operated as follows:

[0066] S1. Prepare PMMA solution: weigh 25 g of PMMA powder and put it into a container, add 100 mL of anisole as solvent, and stir magnetically at room temperature for 1 h until the PMMA particles are completely dissolved to form a uniform PMMA solution;

[0067] S2, spin coating PMMA solution: Place the Te layer material on the mica carrier on a spin coater, drop the PMMA solution on the surface of the Te layer material, then increase the speed from 500 rpm to 2500 rpm, and then spin coat at 2500 rpm for 120 s to form a PMMA thin film layer with a thickness of 300 nm;

[0068] S3, baking: Place the sample coated with the PMMA layer on a hot plate at 120°C and bake for 3 minutes to make the PMMA and the Te layer material layer closely attached;

[0069] S4, removing the mica carrier: slowly immerse the sample coated with the PMMA layer into a container filled with deionized water. Since PMMA is hydrophobic, use tweezers to separate the PMMA layer from the mica layer, and it will float on the surface of the solution, thereby achieving the separation of the Te material and the mica carrier;

[0070] S5, transfer Te material: drag the PMMA film onto the Si / SiO2 substrate with tweezers to make it contact with the Si / SiO2 substrate;

[0071] S6. Heating the Si / SiO2 substrate: slowly heating the Si / SiO2 substrate to 100°C to remove moisture adsorbed on the sample surface and promote full adsorption of the PMMA polymer film and the Si / SiO2 substrate;

[0072] S7, removing the PMMA film: immersing the Si / SiO2 substrate in an acetone solution to remove the PMMA polymer film, thus completing the wet transfer of the Te layer material;

[0073] (3) Select a second Si / SiO2 substrate and use a mechanical stripping method to adhere the ReSe2 material to the Si / SiO2 substrate. The thickness of the ReSe2 layer formed on the Si / SiO2 substrate is 50-100 nm, the width is 10-40 μm, and the length is 40-120 μm. Repeat 4 times to obtain four identical ReSe2 layer materials, whose thicknesses are S1: 99 nm, S2: 67 nm, S3: 75 nm, S4: 60 nm; their widths are S1: 14 μm, S2: 17 μm, S3: 15 μm, S4: 16 μm; their lengths are S1: 54 μm, S2: 53 μm, S3: 45 μm, S4: 38 μm;

[0074] (4) 5 g of polyvinyl alcohol (PVA) particles were mixed with 80 mL of deionized water to obtain a polyvinyl alcohol solution, and the polyvinyl alcohol solution was dropped onto a polydimethylsiloxane (PMDS) film and dried at 55 °C for 10 min until a layer of solidified polyvinyl alcohol film was formed on the polydimethylsiloxane film; the ReSe2 layer was transferred to a Si / SiO2 substrate containing a Te layer using the polyvinyl alcohol film through a transfer platform, thus forming a structure in which the substrate was Si / SiO2, the bottom layer was a Te layer, and the upper layer was a ReSe2 layer;

[0075] Repeat the operation to form four van der Waals heterojunctions with the Te layer at four angles of 0°, 30°, 60° and 90° respectively.

[0076] (5) Spin-coat the photoresist on the Te layer and the ReSe2 layer using a photoresist spreader, then heat on a hot plate at 105°C for 4 min and expose. The specific process parameters are: the scanning speed of the photolithography machine is 0.3 mm / s, the power is 19 mW, the developer concentration is 4% tetramethylammonium hydroxide aqueous solution, and the development time is 19 s. Electrode patterns are obtained on the Te layer and the ReSe2 layer.

[0077] (6) Deposit metal Ti / Au on the obtained electrode pattern mask by electron beam thermal evaporation, wherein the Ti layer is in contact with the insulating dielectric layer SiO2 and has a thickness of 10 nm, and the Au layer has a thickness of 100 nm; the specific evaporation method is as follows: first, place the Ti and Au materials in the corresponding crucibles respectively and turn on the circulating cooling water switch of the equipment, place the device to be evaporated in the inner cavity of the equipment, and then evacuate the equipment and preheat the electron gun: before starting the evaporation, preheat the cathode filament of the electron gun, usually the preheating current is 0.6 A, and the preheating time of the new cathode is not less than 5 min; first, pre-melt the Ti and Au materials to remove impurities on the surface of the materials and ensure uniform melting of the materials; first evaporate Ti (10 nm): adjust the power and beam current of the electron gun to start evaporating the Ti layer; then evaporate the Au layer (70 nm): After the Ti layer is evaporated, adjust the power and beam current of the electron gun to start evaporating the Au layer; after the evaporation is completed, turn off the electron beam, wait for the device to cool to room temperature, take out the device, and then remove the excess photoresist with acetone solution;

[0078] (7) The electrode on the two-dimensional material Te is connected to the drain electrode, and the electrode on the two-dimensional material ReSe2 is connected to the source electrode. The two-dimensional Te / ReSe2 variable-angle heterojunction photodetector is obtained by high-temperature annealing at 150°C for 120 min in an Ar / N2 mixed atmosphere.

[0079] Figure 1 This is a planar structural diagram of the two-dimensional Te / ReSe2 variable-angle heterojunction photodetector prepared in Example 1, wherein the angles between ReSe2 and Te are 0°, 30°, 60°, and 90°, S1-S4 are source electrodes, and D is the drain electrode.

[0080] Figure 2 This is an optical image of the two-dimensional Te / ReSe2 variable-angle heterojunction photodetector prepared in Example 1, where the angles between ReSe2 and Te are 0°, 30°, 60°, and 90°, S1-S4 are source electrodes, and D is the drain electrode.

[0081] Figure 3 This is a Raman graph of the two-dimensional Te / ReSe2 variable angle heterojunction photodetector prepared in Example 1. The Raman spectrum shows that the characteristic peaks of the single material and the heterojunction material are consistent with the characteristics of Te and ReSe2 materials, proving that the materials are Te and ReSe2.

[0082] Figure 4 This is the polarization Raman graph of the two-dimensional Te / ReSe2 variable-angle heterojunction photodetector prepared in Example 1. Figure 4It can be shown that the Raman vibration modes of ReSe2 and Te exhibit strong periodic changes, proving that the materials have polarization properties, laying the foundation for subsequent testing of polarization-sensitive photoelectric responses.

[0083] Figure 5 This is a test diagram of the polarization performance of the two-dimensional Te / ReSe2 variable-angle heterojunction photodetector prepared in Example 1. The polarization ratio of the S1 device is 2.45, the polarization ratio of the S2 device is 2.51, the polarization ratio of the S3 device is 1.83, and the polarization ratio of the S4 device is 1.72. Based on the characteristics of the device, it can be applied to polarization imaging.

[0084] For polarized light of fixed direction and fixed intensity, S1-S4 devices will respond to different signals. The signal of the two-dimensional Te / ReSe2 variable-angle heterojunction photodetector prepared in Example 1 is processed and decoupled to obtain Table 1.

[0085] Table 1

[0086]

[0087] Based on the content in Table 1, it is possible to detect polarization direction and intensity simultaneously, and it can also be applied to encryption / decryption.

[0088] Figure 6 This is the wide-spectrum response graph of the two-dimensional Te / ReSe2 variable-angle heterojunction photodetector prepared in Example 1, indicating that the device responds in the range of 400-1000 nm.

[0089] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A two-dimensional Te / ReSe2 variable angle heterojunction photodetector, characterized in that: From bottom to top, there are Si / SiO2 substrate, Te layer and ReSe2 layer, wherein the ReSe2 layer and the Te layer form van der Waals heterojunctions at different angles; The method for preparing the two-dimensional Te / ReSe2 variable angle heterojunction photoelectric detector comprises the following steps: The Te material was grown on a mica substrate by chemical vapor deposition, and then transferred to a Si / SiO2 substrate by a polymethyl methacrylate wet transfer method. The ReSe2 material was adhered to another Si / SiO2 substrate by mechanical stripping, and then the ReSe2 material adhered to the Si / SiO2 substrate was transferred to the Si / SiO2 substrate containing Te material at different angles and in different sequences by polyvinyl alcohol dry transfer method, thus preparing Te / ReSe2 heterojunction structures with different contact angles. The required electrode pattern is prepared on a Si / SiO2 substrate containing a Te / ReSe2 heterojunction structure through maskless lithography and development, and then metal is evaporated on the obtained electrode pattern mask to form an electrode; the photoresist is removed with acetone, and vacuum high-temperature annealing is performed to obtain a Te / ReSe2 device with different contact angles, namely a two-dimensional Te / ReSe2 variable-angle heterojunction photodetector.

2. The two-dimensional Te / ReSe2 variable angle heterojunction photodetector according to claim 1, characterized in that: The electrode on the Te layer is connected to the drain electrode; and / or The electrode on the ReSe2 layer is connected to the source electrode; and / or The angle is 0-90°; and / or The number of ReSe2 layers is more than 3; and / or The Te layer has a thickness of 40-100 nm, a width of 10-30 μm, and a length of 60-200 μm; and / or The ReSe2 layer has a thickness of 40-100 nm, a width of 10-40 μm, and a length of 40-120 μm.

3. A method for preparing a two-dimensional Te / ReSe2 variable angle heterojunction photodetector as claimed in any one of claims 1 to 2, characterized in that: The following steps are involved: The Te material was grown on a mica substrate by chemical vapor deposition, and then transferred to a Si / SiO2 substrate by a polymethyl methacrylate wet transfer method. The ReSe2 material was adhered to another Si / SiO2 substrate by mechanical stripping, and then the ReSe2 material adhered to the Si / SiO2 substrate was transferred to the Si / SiO2 substrate containing Te material at different angles and in different sequences by polyvinyl alcohol dry transfer method, thus preparing Te / ReSe2 heterojunction structures with different contact angles. The required electrode pattern is prepared on a Si / SiO2 substrate containing a Te / ReSe2 heterojunction structure through maskless lithography and development, and then metal is evaporated on the obtained electrode pattern mask to form an electrode; the photoresist is removed with acetone, and vacuum high-temperature annealing is performed to obtain a Te / ReSe2 device with different contact angles, namely a two-dimensional Te / ReSe2 variable-angle heterojunction photodetector.

4. The method for preparing the two-dimensional Te / ReSe2 variable angle heterojunction photodetector according to claim 3, characterized in that: In the chemical vapor deposition process, In2Te3 powder is used as raw material, mica is used as carrier, Ar / N2 mixed gas is used as carrier gas, and the equipment is a high-temperature tube furnace. The temperature control method of the chemical vapor deposition process is: in the first stage, the temperature is raised from room temperature to 720-750°C after 35 minutes, and the carrier gas flow rate is 90-100sccm; in the second stage, the temperature is kept at 720-750°C for 15 minutes, and the carrier gas flow rate is 90-100sccm; in the third stage, the temperature is naturally cooled to room temperature, and the gas flow is adjusted to 30-40sccm before it drops to 100°C, and the carrier gas is turned off when it drops below 100°C.

5. The method for preparing the two-dimensional Te / ReSe2 variable angle heterojunction photodetector according to claim 3, characterized in that: The specific operation steps of the polyvinyl alcohol dry transfer method include: dropping a polyvinyl alcohol solution on a polydimethylsiloxane film, drying at 55-70°C for 5-10 minutes, and forming a layer of solidified polyvinyl alcohol film on the polydimethylsiloxane film; transferring the ReSe2 material to the Te material using the polyvinyl alcohol film through a transfer platform to form a heterojunction.

6. The method for preparing the two-dimensional Te / ReSe2 variable angle heterojunction photodetector according to claim 3, characterized in that: The specific preparation steps of the electrode pattern include: spin coating the photoresist using a photoresist spreader, heating on a hot plate at 100-105°C for 3-6 minutes, and exposing; the specific process parameters are: the scanning speed of the photolithography machine is 0.06-0.5mm / s, the power is 6-19mW, the developer is a tetramethylammonium hydroxide aqueous solution with a concentration of 3-6%, and the development time is 18-25s.

7. The method for preparing the two-dimensional Te / ReSe2 variable angle heterojunction photodetector according to claim 3, characterized in that: The metal evaporation refers to evaporation of Ti / Au to form electrodes.

8. The method for preparing the two-dimensional Te / ReSe2 variable angle heterojunction photodetector according to claim 3, characterized in that: The high temperature annealing conditions are: temperature 100-200° C., atmosphere Ar / N 2 mixed gas, and time 30-120 min.

9. An application of the two-dimensional Te / ReSe2 variable-angle heterojunction photodetector as described in any one of claims 1 to 2 in a polarization-sensitive photodetector.

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