A broadband photodetector based on two-dimensional magnetic materials and a preparation method thereof

Abstract

The present invention discloses a broadband photodetector based on two-dimensional magnetic materials and a preparation method thereof, which is prepared with silica as a supporting substrate, a two-dimensional magnetic single-crystal thin film as a channel layer, metal electrodes as an electrode layer, and hBN as a packaging layer, wherein the two-dimensional magnetic single-crystal thin film is obtained by mechanical exfoliation of two-dimensional magnetic single-crystal materials; the response time of the broadband photodetector in the visible light region is 121.7 ms, and the responsivity is 26.1 A / W. By exploring the interaction between the magnetic properties and optoelectronic properties of two-dimensional magnetic materials, the present invention has great potential in the development of advanced spin-optoelectronic device applications.

Description

Technical Field

[0001] The present invention belongs to the technical field of photodetectors, and particularly relates to a broadband photodetector based on two-dimensional magnetic materials and a preparation method thereof. Background Art

[0002] With the rapid development of modern information society, microelectronic devices will continue to develop in the direction of faster speed, smaller size, cheaper price and more perfect functions; in the post-Moore era, chips integrate multiple functions such as computing, storage, communication and information processing, promoting revolutionary changes in information technology. People are constantly moving forward towards miniaturized and multifunctional application devices with higher storage density, faster reading and writing speed and lower energy consumption. For traditional silicon-based semiconductor material processes, the reduction of device size is bound to be restricted by quantum effects, making it difficult to significantly improve performance and reach the theoretical predicted limit. People have gradually turned their attention to new materials at the two-dimensional scale, aiming to endow them with the important mission of continuing Moore's Law. New two-dimensional materials such as graphene and transition metal sulfide compounds with unique optical, electrical and magnetic properties and new quantum physical phenomena have potential application prospects in information, micro-nano optoelectronic devices, etc., promoting the development of chip technology. With the continuous expansion of the two-dimensional material family, more and more new two-dimensional materials have been discovered and shown unique properties, providing a basis for broader research and applications and promising to lead a new industrial revolution.

[0003] Two-dimensional intrinsic magnetic materials can use the spin degree of freedom of electrons as information carriers for data storage and logical operations, with outstanding advantages such as fast data processing speed, high circuit integration and low energy consumption. Their discovery has rapidly developed spintronics into an extremely attractive field. For example, based on these two-dimensional materials, high-density magnetic storage, magnetic tunnel junctions and ultra-thin spintronic devices can be realized, attracting extensive research interest. The weak interaction coupling and atomic-scale thickness of two-dimensional materials make the interfacial magnetic interaction play a prominent role, providing a new research platform for regulating magnetic interface coupling to realize the application of complex magnetic interactions in spintronics and magnetic devices. So far, a large amount of work on the magnetic-optical / electrical properties of two-dimensional materials has been reported. In order to further study two-dimensional magnetic materials and promote their applications, exploring the interaction between magnetic and optoelectronic properties and developing spin-optoelectronic detection devices are promising research strategies. Therefore, it is urgently needed to explore the optoelectronic properties of two-dimensional magnetic materials and develop broadband photodetectors based on magnetic two-dimensional materials. Summary of the Invention

[0004] The object of the present invention is to provide a wide-band photodetector based on two-dimensional magnetic materials and a preparation method thereof, which can develop a spin-optoelectronic device based on the interaction between the magnetic and optoelectronic properties of two-dimensional magnetic materials and has great application prospects.

[0005] To achieve the above object, the present invention provides a wide-band photodetector based on two-dimensional magnetic materials, which is prepared with a silicon dioxide as a supporting substrate, a two-dimensional magnetic single-crystal thin film as a channel layer, metal electrodes as an electrode layer, and hBN as a packaging layer, wherein the two-dimensional magnetic single-crystal thin film is prepared by mechanically exfoliating two-dimensional magnetic single-crystal materials; the response time of the wide-band photodetector in the visible light region is 121.7 ms, and the responsivity is 26.1 A / W.

[0006] The two-dimensional magnetic single-crystal materials are prepared by a flux method or a chemical vapor transport method, and the chemical vapor transport method includes the following steps:

[0007] (1) Mix iron powder, tantalum powder and sulfur powder, heat them to 400-500 °C within 5 h under a closed condition, keep them for 24 h, then continue to heat them to 950-1050 °C within 5 h and keep them for 48 h to obtain a powder crystal material.

[0008] (2) Grind the powder crystal material and mix it with a transport agent, heat it to 600-800 °C within 10 h under a closed condition, keep it warm for 7 d, quickly cool it to room temperature after the reaction ends, and collect two-dimensional magnetic single-crystal materials in the low-temperature region.

[0009] Furthermore, the flux method includes the following steps:

[0010] (1) Mix iron powder, tantalum powder and sulfur powder, heat them to 400-500 °C within 5 h under a closed condition, keep them for 24 h, then continue to heat them to 950-1050 °C within 5 h and keep them for 48 h to obtain a powder crystal material.

[0011] (2) Cool the powder crystal material to room temperature, grind it, mix it with a flux, heat it to 850-950 °C under a closed condition and keep it for 9-12 h, then cool it to 650-750 °C and keep it for 45-50 h.

[0012] (3) After cooling the primary product obtained in step (2) to room temperature, wash and vacuum dry it to obtain the product.

[0013] Furthermore, the stoichiometric ratio of iron powder, tantalum powder and sulfur powder is 0.26-0.8:0.5-1:2, the transport agent is iodine, and the mass ratio of the transport agent to the powder crystal material is 1:10.

[0014] Furthermore, the co-solvent is obtained by mixing sodium salt and potassium salt with a mass ratio of 7:3, and the mass ratio of the co-solvent to the primary product is 4-6:1.

[0015] Furthermore, the cooling rate in step (2) is 1-2 °C / h, and the cleaning solution for cleaning in step (3) is deionized water and absolute ethanol.

[0016] The present invention also discloses a preparation method of the above-mentioned broadband optoelectronic detector based on two-dimensional magnetic materials, including the following steps:

[0017] S1. After heating the sample stage to 55-65 °C, lift the two-dimensional magnetic single crystal thin film on the silica substrate by PC dry transfer;

[0018] S2. Pre-evaporate an electrode layer on another silica substrate, and attach the PC transfer film with the two-dimensional magnetic single crystal thin film in S1 to the electrode layer, and heat to 170-190 °C;

[0019] S3. After dissolving the PC transfer film of the device prepared in S2, cover and package the device by PC dry transfer to complete the preparation.

[0020] Furthermore, the lifting step in S1 is specifically: attach a corner of the PC dry transfer film to the silica substrate with the two-dimensional magnetic single crystal thin film, cool to room temperature, and then lift the glass slide to realize the transfer of the two-dimensional magnetic single crystal thin film.

[0021] Furthermore, the method for dissolving the PC transfer film in S3 is: place the device prepared in S2 in chloroform.

[0022] In summary, the present invention has the following advantages:

[0023] 1. The present invention develops a spin-optoelectronic device for the first time based on the interaction between the magnetic and optoelectronic properties of two-dimensional magnetic materials, and exhibits good broadband optoelectronic response (response time in the visible light region: 121.7 ms, responsivity: 26.1 A / W), and has great potential in the development of advanced spin-optoelectronic device applications.

[0024] 2. Emerging magnetic materials are crucial for the field of spintronics and will revolutionize the development of information technology. Ferromagnetic materials can use spin electrons as the information carriers for device operation instead of electrons, and have outstanding advantages such as high storage density, fast data processing speed, high circuit integration density, and low energy consumption, providing great opportunities for the post-Moore's law era. By combining broadband optoelectronic performance and magnetism, the interaction between magnetism and photocurrent can be explored to develop spin-optoelectronic device applications. Description of the Drawings

[0025] Figure 1 The prepared two-dimensional magnetic material Fe 0.75 Ta 0.5 XRD and SEM images of S2;

[0026] Figure 2 The prepared two-dimensional magnetic material Fe 0.75 Ta 0.5 Magnetic performance diagram of S2;

[0027] Figure 3 The prepared two-dimensional magnetic material Fe 0.75 Ta 0.5 Field dependence curves of S2 magnetoresistance at different temperatures;

[0028] Figure 4 For the preparation of Fe 0.75 Ta 0.5 Optical images and optoelectronic performance of the S2 photodetector. DETAILED DESCRIPTION

[0029] The principles and features of the present invention are described below in conjunction with the examples, which are only used to explain the present invention and are not intended to limit the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to conventional conditions or the conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments is not specified, they are all conventional products that can be purchased commercially.

[0030] Example 1

[0031] This embodiment provides a broadband photoelectric detector made of a two-dimensional magnetic material, which is manufactured by the following steps:

[0032] 1) In a glove box, high-purity Fe powder, Ta powder and S powder were weighed in a stoichiometric ratio of 0.26:1:2 and fully mixed in a mortar;

[0033] 2) Put the fully ground raw materials into a pre-prepared quartz tube and evacuate and seal it;

[0034] 3) placing the sealed quartz tube in a muffle furnace, raising the temperature to 450° C. within 5 hours and maintaining it for 1 day; then raising the temperature to 1000° C. within 5 hours and maintaining it for 2 days to obtain the corresponding powder crystal material;

[0035] 4) After the powder crystal material is fully ground, 0.5 g of the powder crystal is transferred to the prepared quartz tube (1.3 cm in diameter and 27 cm in length), and 50 mg of iodine is added as a transfer agent; then, the quartz tube is vacuum-sealed. The sealed quartz tube is placed in a dual-temperature zone tube furnace, and the temperature is raised to 750°C within 10 hours and maintained for one week; after the reaction is completed, the quartz tube is removed from the tube furnace and quickly cooled to room temperature;

[0036] 5) Screen out pure Fe using XRD 1 / 4 TaS2 single crystal sample (ferromagnetic);

[0037] 6) Select SiO2 as the supporting substrate, and use the mechanical exfoliation method to obtain few-layer sample flakes from the screened crystals. Find a suitable sample under the assistance of a microscope and make a mark;

[0038] 7) First, heat the sample stage to 60 °C. Under the assistance of a microscope and a three-dimensional displacement stage, slowly and evenly attach one corner of the PC dry transfer film to the SiO2 substrate with the thin-layer sample, slowly cool it to room temperature, and slowly lift the glass slide. The PC film will lift the sample flake;

[0039] 8) Under the assistance of a microscope and a three-dimensional displacement stage, slowly and evenly attach the PC film with the sample flake to the pre-evaporated Cr / Au electrode on the SiO2 substrate, and heat to 180 °C to leave the PC film and the sample flake on the pre-evaporated electrode;

[0040] 9) Place the fabricated device in chloroform to dissolve the PC on the sample surface;

[0041] 10) Using the same method, cover a layer of hBN on the surface of the thin-layer sample to achieve encapsulation protection and complete the preparation of the photodetector;

[0042] 11) Then, the photoelectric properties of the fabricated detector can be measured in detail using a probe station and a semiconductor analyzer.

[0043] Example 2

[0044] This example provides a broadband photodetector for two-dimensional magnetic materials, which is prepared through the following steps:

[0045] 1) Weigh high-purity Fe powder, Ta powder, and S powder in a glove box according to the stoichiometric ratio of 0.34:1:2, and mix them thoroughly in a mortar;

[0046] 2) Put the well-ground raw materials into a pre-prepared quartz tube, evacuate and seal it;

[0047] 3) Place the sealed quartz tube in a muffle furnace, heat it to 450 °C within 5 hours, and keep it for 1 day; then heat it to 1000 °C within 5 hours and maintain it for 2 days to obtain the corresponding powder crystal material;

[0048] 4) After sufficiently grinding the obtained pink crystal material, weigh 0.5 g of the pink crystal and transfer it to a prepared quartz tube (1.3 cm in diameter and 27 cm in length), and add 50 mg of iodine as a transport agent; subsequently, evacuate and seal the quartz tube; place the sealed quartz tube in a two-temperature-zone tube furnace, and raise the temperature to 750 °C within 10 hours and maintain it for one week; after the reaction is completed, take out the quartz tube from the tube furnace and quickly cool it to room temperature;

[0049] 5) Use XRD to screen out pure Fe 1 / 3 TaS2 single crystal sample (ferromagnetic);

[0050] 6) Select SiO2 as the supporting substrate, and obtain few-layer sample flakes from the screened crystals by mechanical exfoliation method. Find a suitable sample under the assistance of a microscope and make a mark;

[0051] 7) First, heat the sample stage to 60 °C. Under the assistance of a microscope and a three-dimensional displacement stage, slowly and evenly attach one corner of the PC dry transfer film to the SiO2 substrate with a thin-layer sample, slowly cool it to room temperature, and slowly lift the glass slide. The PC film will lift the sample flake;

[0052] 8) At room temperature, under the assistance of a microscope and a three-dimensional displacement stage, slowly and evenly attach the PC film with the sample flake to the pre-evaporated Cr / Au electrode on the SiO2 substrate, and heat it to 180 °C to leave the PC film and the sample flake on the pre-evaporated electrode;

[0053] 9) Place the prepared device in chloroform to dissolve the PC on the sample surface;

[0054] 10) Using the same method, cover a layer of hBN on the surface of the thin-layer sample to achieve encapsulation protection and complete the preparation of the photodetector;

[0055] 11) Then, the photoelectric properties of the prepared detector can be tested in detail using a probe station and a semiconductor analyzer.

[0056] Example 3

[0057] This example provides a broadband photodetector for two-dimensional magnetic materials, which is prepared through the following steps:

[0058] 1) In a glove box, weigh high-purity Fe powder, Ta powder and S powder according to the stoichiometric ratio of 0.41:1:2, and mix them thoroughly in a mortar;

[0059] 2) Put the sufficiently ground raw materials into a prepared quartz tube, evacuate and seal it;

[0060] 3) placing the sealed quartz tube in a muffle furnace, raising the temperature to 450° C. within 5 hours and maintaining it for 1 day; then raising the temperature to 1000° C. within 5 hours and maintaining it for 2 days to obtain the corresponding powder crystal material;

[0061] 4) After the powder crystal material is fully ground, 0.5 g of the powder crystal is transferred to the prepared quartz tube (1.3 cm in diameter and 27 cm in length), and 50 mg of iodine is added as a transfer agent; then, the quartz tube is vacuum-sealed. The sealed quartz tube is placed in a dual-temperature zone tube furnace, and the temperature is raised to 750°C within 10 hours and maintained for one week; after the reaction is completed, the quartz tube is removed from the tube furnace and quickly cooled to room temperature;

[0062] 5) Use XRD to screen out pure Fe 0.4 TaS2 single crystal sample (antiferromagnetic);

[0063] 6) SiO2 was selected as the support substrate, and a few-layer sample slices were obtained from the screened crystals by mechanical exfoliation. The appropriate samples were found and marked with the help of a microscope;

[0064] 7) First, heat the sample stage to 60°C. With the help of a microscope and a three-dimensional translation stage, use a corner of the PC dry transfer film to slowly and evenly attach it to the SiO2 substrate with the thin layer of sample. Slowly cool it to room temperature, slowly lift the glass sheet, and the PC film will lift the sample slice.

[0065] 8) At room temperature, with the aid of a microscope and a three-dimensional translation stage, slowly and evenly attach the PC film with the sample flakes to the pre-evaporated Cr / Au electrode on the SiO2 substrate, and heat to 180°C to leave the PC film and the sample flakes on the pre-evaporated electrode;

[0066] 9) Place the prepared device in chloroform to dissolve the PC on the surface of the sample;

[0067] 10) Using the same method, a layer of hBN is covered on the surface of the thin layer sample to achieve encapsulation protection and complete the preparation of the photodetector;

[0068] 11) Use a probe station and semiconductor analyzer to conduct detailed tests on the photoelectric performance of the prepared detector.

[0069] Example 4

[0070] This embodiment provides a broadband photoelectric detector made of a two-dimensional magnetic material, which is manufactured by the following steps:

[0071] 1) In a glove box, high-purity Fe powder, Ta powder and S powder were weighed in a stoichiometric ratio of 0.75:0.5:2 and fully mixed in a mortar;

[0072] 2) Put the well-ground raw materials into a pre-prepared quartz tube, evacuate and seal it.

[0073] 3) Place the sealed quartz tube into a muffle furnace, heat it to 450 °C within 5 hours and keep it for 1 day; then heat it to 1000 °C within 5 hours and maintain it for 2 days to obtain the corresponding powder crystal material.

[0074] 4) After thoroughly grinding the obtained powder crystal material, weigh 0.2 g of the powder crystal and transfer it to a prepared quartz tube. Add a certain amount of NaCl / KCl (7:3) cosolvent to about 1 / 3 (the mass ratio of the raw material to the cosolvent is 1:5). Then, evacuate and seal the quartz tube. Put the sealed quartz tube into a muffle furnace, slowly heat it to 900 °C and keep it for 10 hours; then cool the quartz tube at a rate of 1 °C / h to 700 °C and keep it at 700 °C for 2 days; after the reaction is completed, take out the quartz tube from the muffle furnace and quickly cool it to room temperature. Wash the cosolvent with deionized water and absolute ethanol many times, and vacuum dry to obtain single crystal samples.

[0075] 5) Use XRD to screen out pure Fe 0.75 Ta 0.5 S2 single crystal samples (coexistence of spin glass and antiferromagnetism);

[0076] 6) Select SiO2 as the supporting substrate, and obtain few-layer sample flakes from the screened crystals by mechanical exfoliation method. Find suitable samples under the assistance of a microscope and make marks.

[0077] 7) First, heat the sample stage to 60 °C. Under the assistance of a microscope and a three-dimensional displacement stage, slowly and evenly attach one corner of the PC dry transfer film to the SiO2 substrate with a thin-layer sample, slowly cool it to room temperature, and slowly lift the glass slide. The PC film will lift the sample flake.

[0078] 8) At room temperature, under the assistance of a microscope and a three-dimensional displacement stage, slowly and evenly attach the PC film with the sample flake to the pre-evaporated electrode on the SiO2 substrate, and heat it to 180 °C to leave the PC film and the sample flake on the pre-evaporated electrode.

[0079] 9) Place the prepared device in chloroform to dissolve the PC on the sample surface.

[0080] 10) Using the same method, cover a layer of hBN on the surface of the thin-layer sample to achieve encapsulation protection and complete the preparation of the photodetector.

[0081] 11) Use a probe station and a semiconductor analyzer to conduct a detailed test on the optoelectronic performance of the prepared detector.

[0082] Example 5

[0083] This embodiment provides a broadband photodetector based on two-dimensional magnetic materials, which is prepared through the following steps:

[0084] 1) Weigh high-purity Fe powder, Ta powder, and S powder in a glove box according to a stoichiometric ratio of 0.81:0.5:2, and mix them thoroughly in a mortar.

[0085] 2) Put the well-ground raw materials into a pre-prepared quartz tube, evacuate and seal it.

[0086] 3) Place the sealed quartz tube in a muffle furnace, heat it to 450 °C within 5 hours, and keep it for 1 day; then heat it to 1000 °C within 5 hours and maintain it for 2 days to obtain the corresponding powder crystal material.

[0087] 4) After thoroughly grinding the obtained powder crystal material, weigh 0.2 g of the powder crystal and transfer it to a prepared quartz tube. Add a certain amount of NaCl / KCl (7:3) flux to about 1 / 3 (the mass ratio of the raw material to the flux is 1:5). Then, evacuate and seal the quartz tube; put the sealed quartz tube into a muffle furnace, slowly heat it to 900 °C and keep it for 10 hours; then cool the quartz tube at a rate of 1 °C / h to 700 °C and keep it at 700 °C for 2 days; after the reaction is completed, take out the quartz tube from the muffle furnace and quickly cool it to room temperature. Wash the flux with deionized water and anhydrous ethanol multiple times, and vacuum dry to obtain a single crystal sample.

[0088] 5) Use XRD to screen out pure Fe 0.8 Ta 0.5 S2 single crystal sample (coexistence of spin glass and antiferromagnetism);

[0089] 6) Select SiO2 as the supporting substrate, and use the mechanical exfoliation method to obtain a few-layer sample flake from the screened crystal. Find a suitable sample under the assistance of a microscope and make marks.

[0090] 7) First, heat the sample stage to 60 °C. Under the assistance of a microscope and a three-dimensional displacement stage, slowly and evenly attach a corner of the PC dry transfer film to the SiO2 substrate with a thin-layer sample, slowly cool it to room temperature, and slowly lift the glass slide. The PC film will lift the sample flake.

[0091] 8) At room temperature, under the assistance of a microscope and a three-dimensional displacement stage, slowly and evenly attach the PC film with the sample flake to the pre-evaporated Cr / Au electrode on the SiO2 substrate, and heat it to 180 °C to leave the PC film and the sample flake on the pre-evaporated electrode.

[0092] 9) Place the prepared device in chloroform to dissolve the PC on the sample surface.

[0093] 10) Using the same method, a layer of hBN is covered on the surface of the thin-film sample to achieve encapsulation protection, and the preparation of the photodetector is completed;

[0094] 11) The optoelectronic properties of the prepared detector are tested in detail using a probe station and a semiconductor analyzer.

[0095] Test example

[0096] As Figure 1 shown, Figure 1 is the characterization diagram of the prepared magnetic two-dimensional material Fe 0.75 Ta 0.5 S2, where Figure 1 (a) is the XRD, Figure 1 (b) is the SEM picture. It can be seen that the XRD of the polycrystalline powder after grinding the single crystal is completely coincident with the standard card of the target material, indicating that the target material is successfully obtained. The surface morphology of the SEM shows its typical two-dimensional characteristics.

[0097] As Figure 2 shown, Figure 2 is the magnetic property of the prepared magnetic two-dimensional material Fe 0.75 Ta 0.5 S2. Among them, Figure 2(a) is the zero-field cooling and field-cooling curves when a 1T magnetic field is applied in the out-of-plane and in-plane directions, Figure 2 (b) is the hysteresis loop of the sample when cooled from room temperature to different temperatures under a 7T magnetic field, Figure 2 (c) is the hysteresis loop of the sample after being cooled from room temperature to 2K after applying a 7T magnetic field, Figure 2 (d) is the hysteresis loop when cooled from room temperature to 2K after applying 7T and -7T magnetic fields. It can be seen that, Figure 2 (a) shows its magnetic characteristics, Figure 2 (b)-(d) illustrate that the material has a stable exchange bias field.

[0098] Figure 2 (a) shows the temperature-dependent curves of the magnetization intensity of the Fe 0.75 Ta 0.5 S2 single crystal under zero-field cooling and field cooling, where a 1T magnetic field is applied along the in-plane and out-of-plane directions of the crystal. The zero-field cooling and field-cooling curves separate below ~30K, indicating the presence of a freezing torque in the sample. This is in line with the typical characteristics of spin-glass. Figure 2 (b) shows the Fe 0.75 Ta 0.5Magnetization related to the magnetic field of S2 at different temperatures. At low temperatures, an obvious hysteresis loop appears, and there is still no sign of saturation even when the magnetic field reaches 7 T. This behavior is consistent with the spin-glass characteristics mentioned above. When Fe 0.75 Ta 0.5 When S2 is cooled in a magnetic field of 7 T, the center of the hysteresis loop shows a significant shift towards the negative magnetic field, which is consistent with the exchange bias phenomenon. As the temperature increases, Fe 0.75 Ta 0.5 The exchange bias effect of S2 gradually becomes blurred. At higher temperatures (e.g., 100 K), the M-H curve becomes a linear straight line without a hysteresis loop, and the coercive field (Hc, defined as the half-width of the hysteresis loop at the average value of the zero-field intercept of the hysteresis loop) is basically negligible

[0099] As Figure 3 shown, Figure 3 For the prepared magnetic two-dimensional material Fe 0.75 Ta 0.5 Field dependence curves of the magnetoresistance of S2 at different temperatures, Figure 3 (a) shows the field dependence curves of the magnetoresistance of Fe 0.75 Ta 0.5 S2 at different temperatures. After applying a magnetic field, the magnetoresistance of the material shows an obvious negative magnetoresistance effect, and no sign of saturation is found within the entire magnetic field test range. Below the transition temperature, as the magnetic field changes from -9 T to 9 T, Fe 0.75 Ta 0.5 The magnetoresistance of S2 continuously increases with the magnetic field and reaches a maximum value at the coercive field. As the magnetic field further increases, Fe 0.75 Ta 0.5 The magnetoresistance of S2 begins to rapidly decrease. When the direction of the applied magnetic field is reversed, the same magnetoresistance change is observed, resulting in the field dependence curve of the magnetoresistance showing a bow-tie shape at low temperatures (e.g., 20 K), as Figure 3 (b) shown. This is consistent with the M-H loop. When the applied magnetic field is 9 T, Fe 0.75 Ta 0.5 The absolute value of the negative magnetoresistance of S2 shows a monotonically increasing trend with the decrease of temperature and reaches an extreme value (10%) at 20 K.

[0100] As Figure 4 shown, Figure 4 For the prepared Fe 0.75 Ta 0.5 Optical pictures and optoelectronic properties of the S2 photodetector. Among them Figure 4(a) is the photocurrent resolution curve at different positions when the bias voltage is 1 V, the laser wavelength is 532 nm, Figure 4 (b) is the time-resolved curve of photocurrent under different bias voltages, the laser wavelength is 532 nm, Figure 4 (c) is the time-resolved curve of photocurrent within a single cycle, used to estimate the rise time and fall time, Figure 4 (d) is the curve of the optical power density dependence of the device responsivity and detectivity under different bias voltages and the curve of the optical power density dependence of the photocurrent under different laser wavelengths ( Figure 4 (e): 633 nm @ 0.14 W cm -2 ; Figure 4 (f): 10.6 μm @ 0.23 W cm -2 ) time resolution curve of photocurrent.

[0101] Specifically, Figure 4 (a) can show that the photocurrent comes from the entire channel, Figure 4 (b) can show a stable photocurrent, Figure 4 (c) can show a fast optoelectronic response, Figure 4 (d) can show the responsivity and specific detectivity, Figure 4 (e)- Figure 4 (f) can obtain a broadband optoelectronic response.

[0102] Figure 4 (a) is the position-dependent current distribution of the entire channel of the fabricated photodetector. The photocurrent mainly comes from the entire channel of the photodetector, reflecting the photoconductivity mechanism of the Fe 0.75 Ta 0.5 S2 photodetector. Figure 4(b) is the time-resolved photocurrent of the fabricated Fe 0.75 Ta 0.5 S2 photodetector under different bias voltages under the irradiation of a 532 nm laser wavelength. It can be clearly seen that the device current maintains good stability in both the "On" and "Off" states. Even under a large external bias of 2.0 V and a strong laser power of 2.0 mW, a stable and reproducible photocurrent can be clearly observed. Figure 4 (c) is the amplified time-resolved photocurrent of the fabricated Fe 0.75 Ta 0.5 S2 photodetector within one cycle, reflecting a fast optoelectronic response. The rise time and fall time are 121.7 ms and 206.1 ms respectively. Generally, the rise time is defined as the time required for the photocurrent to increase from 10% to 90% of the maximum value; the fall time is defined as the time required for the photocurrent to decrease from 90% to 10% of the maximum value. Figure 4 (d) is for Fe 0.75 Ta 0.5Light intensity dependence of the responsivity and detectivity of the S2 photodetector under different external bias voltages. At a power density of 1600 W m -2 , with an external bias voltage of 2.0 V, Fe 0.75 Ta 0.5 the responsivity of the S2 photodetector reaches a maximum of 26.1 A W at room temperature, which has great advantages among photodetectors based on two-dimensional materials. -1 Figure 4 (e)-(f) are time-resolved photocurrents under 633 nm and 10.6 mm lasers, demonstrating broadband photoelectric response.

[0103] Although the specific embodiments of the present invention have been described in detail, it should not be construed as a limitation on the protection scope of this patent. Within the scope described in the claims, various modifications and deformations that can be made by those skilled in the art without creative efforts still fall within the protection scope of this patent.​

Claims

1. A preparation method of a broadband photodetector based on two-dimensional magnetic materials, characterized in that, It includes the following steps: S1. After heating the sample stage to 55 - 65 °C, lift the two-dimensional magnetic single-crystal thin film on the silica substrate by PC dry transfer; S2. Pre-evaporate the electrode layer on another silica substrate, attach the PC transfer film with the two-dimensional magnetic single-crystal thin film in S1 to the electrode layer, and heat to 170 - 190 °C; S3. After dissolving the PC transfer film of the device prepared in S2, cover the device with a packaging layer by PC dry transfer to complete the preparation; The broadband photodetector based on two-dimensional magnetic materials is prepared with silica as the supporting substrate, the two-dimensional magnetic single-crystal thin film as the channel layer, the metal electrode as the electrode layer, and hBN as the packaging layer, wherein the two-dimensional magnetic single-crystal thin film is prepared by mechanical exfoliation of two-dimensional magnetic single-crystal materials; The two-dimensional magnetic single-crystal materials are prepared by the flux method or the chemical vapor transport method, wherein the chemical vapor transport method includes the following steps: (1) Mix iron powder, tantalum powder and sulfur powder, and under closed conditions, heat to 400 - 500 °C within 5 h and hold for 24 h, then continue to heat to 950 - 1050 °C within 5 h and hold for 48 h to obtain a powder crystal material; (2) Grind the powder crystal material and mix it with the transport agent, heat to 600 - 800 °C within 10 h under closed conditions, and keep warm for 7 d. After the reaction ends, quickly cool to room temperature, and collect the two-dimensional magnetic single-crystal material in the low-temperature region; The flux method includes the following steps: (1) Mix iron powder, tantalum powder and sulfur powder, and under closed conditions, heat to 400 - 500 °C within 5 h and hold for 24 h, then continue to heat to 950 - 1050 °C within 5 h and hold for 48 h to obtain a powder crystal material; (2) Cool the powder crystal material to room temperature, grind it, mix it with the flux, under closed conditions, heat to 850 - 950 °C and hold for 9 - 12 h, then cool to 650 - 750 °C at a rate of 1 - 2 °C / h and hold for 45 - 50 h; (3) After cooling the primary product prepared in step (2) to room temperature, wash it with deionized water and absolute ethanol and vacuum dry it to obtain; In the chemical vapor transport method and the flux method, the stoichiometric ratios of iron powder, tantalum powder and sulfur powder are all 0.26 - 0.8:0.5 - 1:2, the transport agent is iodine, and the mass ratio of the transport agent to the powder crystal material is 1:10; the flux is obtained by mixing sodium salt and potassium salt with a mass ratio of 7:3, and the mass ratio of the flux to the primary product is 4 - 6:

1.

2. The preparation method of the broadband optoelectronic detector based on two-dimensional magnetic materials according to claim 1, characterized in that, The specific step of lifting in S1 is: Attach a corner of the PC dry transfer film to the silica substrate with the two-dimensional magnetic single-crystal thin film, cool to room temperature, and then lift the glass slide to realize the transfer of the two-dimensional magnetic single-crystal thin film.

3. The preparation method of the broadband photodetector based on two-dimensional magnetic materials according to claim 1, wherein, The method for dissolving the PC transfer film in S3 is: Place the device prepared in S2 in chloroform.

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