Van der Waals tellurium nanometer material with wide-spectrum body photovoltaic response, preparation method and application thereof, photoelectric device and preparation method thereof

Abstract

The invention relates to the technical field of photoelectric materials and devices, in particular to a van der Waals tellurium nanometer material with bulk photovoltaic response, a preparation method and application of the nanometer material, a photoelectric device and a preparation method of the photoelectric device. The invention provides a preparation method of a Van der Waals tellurium nanometer material, which comprises the following steps: by taking selenium telluride as a raw material, carrying out chemical vapor deposition on the surface of a substrate to obtain the Van der Waals tellurium nanometer material, the chemical vapor deposition is carried out under the condition of introducing nitrogen. The van der Waals tellurium nanometer material prepared by the preparation method can enable the bulk photovoltaic response of a photoelectric device to have a wide spectrum band and high photocurrent density.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic materials and devices, and in particular to a van der Waals tellurium nanomaterial with a wide-band bulk photovoltaic response and a preparation method and application thereof, and an optoelectronic device and a preparation method thereof. Background Art

[0002] Efficient photoelectric conversion is crucial in a variety of applications such as imaging, free-space communications, and clean energy. As a second-order optical effect, bulk photovoltaic has become an intensively studied thermoelectric due to its great potential in overcoming the inherent Shockley-Queisser effect limit in conventional pn junction photovoltaics. Initially, bulk photovoltaics were studied in ferroelectric oxide materials such as LiNbO3, BaTiO3, and Pb(Zr) x Ti 1-x The bulk photovoltaic effect observed in )O3) provides unprecedented opportunities for extensive research in a variety of materials. In addition to ferroelectric oxide materials, recent studies have also explored ferroelectric superlattices, perovskite halides, organic crystals, semimetals, and van der Waals materials. Notably, van der Waals materials with low dimensionality, strong symmetry breaking, and high strain compatibility show excellent bulk photovoltaic effects. For example, in-plane tensile strain breaks the inversion symmetry of rhombohedral MoS2 and produces up to 10A cm under 630nm illumination. -2 Bulk photovoltaic response current. Due to interband optical transitions in semiconductors and heterostructures, the current bulk photovoltaic response is mainly concentrated in a limited wavelength range from ultraviolet to visible light. Although Berry curvature and scattering in semimetals can produce mid-wave infrared bulk photovoltaic response, the photoelectric transition probability generated by polarized single-wavelength lasers is low, resulting in a significant decrease in the photocurrent density of the bulk photovoltaic response at the same light power. Therefore, how to achieve a bulk photovoltaic response with a wide spectrum and high photocurrent density is a problem that needs to be solved. Summary of the invention

[0003] The purpose of the present invention is to provide a van der Waals tellurium nanomaterial with a wide-band bulk photovoltaic response, a preparation method and application thereof, a photoelectric device and a preparation method thereof. The van der Waals tellurium nanomaterial prepared by the preparation method can make the bulk photovoltaic response of the photoelectric device have a wide band and high photocurrent density.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides a method for preparing a van der Waals tellurium nanomaterial, comprising the following steps:

[0006] Using selenium telluride as a raw material, chemical vapor deposition is performed on the surface of a substrate to obtain the van der Waals tellurium nanomaterial;

[0007] The chemical vapor deposition is performed under the condition of nitrogen flow.

[0008] Preferably, the substrate includes a silicon substrate, a glass substrate, a mica substrate or a sapphire substrate;

[0009] The thickness of the substrate is 500nm-500μm.

[0010] Preferably, during the nitrogen flow process, the flow rate of nitrogen is 30-80 sccm.

[0011] Preferably, the chemical vapor deposition is carried out under heating conditions;

[0012] The heating temperature is 550-700° C., and the heat preservation time is 20-60 minutes.

[0013] The present invention also provides a van der Waals tellurium nanomaterial prepared by the preparation method described in the above technical solution. The van der Waals tellurium nanomaterial has a length of 3.73 to 12.28 μm and a thickness of less than 200 nm.

[0014] The present invention also provides the application of the van der Waals tellurium nanomaterial described in the above technical solution in optoelectronic devices.

[0015] The present invention also provides a photoelectric device, comprising a van der Waals tellurium nanomaterial and metal electrodes at both ends of the van der Waals tellurium nanomaterial;

[0016] The van der Waals tellurium nanomaterial is the van der Waals tellurium nanomaterial described in the above technical solution.

[0017] Preferably, the distance between the metal electrodes at both ends of the van der Waals tellurium nanomaterial is 2.5 to 14.5 μm;

[0018] The width of the van der Waals tellurium nanomaterial is 0.2-7.8 μm.

[0019] Preferably, the material of the metal electrode is one or more of gold, platinum and palladium.

[0020] The present invention also provides a method for preparing the optoelectronic device described in the above technical solution, comprising the following steps:

[0021] After coating photoresist on a substrate having a van der Waals tellurium nanomaterial on its surface, a van der Waals tellurium nanomaterial is selected, and electron beam lithography and development are performed in sequence until positions for preparing electrodes are exposed at both ends of the selected van der Waals tellurium nanomaterial, and then electrodes are evaporated and the photoresist is removed to obtain the optoelectronic device.

[0022] The present invention provides a method for preparing a van der Waals tellurium nanomaterial, comprising the following steps: using selenium telluride as a raw material, performing chemical vapor deposition on the surface of a substrate to obtain the van der Waals tellurium nanomaterial; the chemical vapor deposition is performed under the condition of nitrogen. Since each Te atom in the van der Waals tellurium nanomaterial is covalently bonded to its two nearest neighbors, a spiral chain is formed. The Te bond is surrounded and stacked by the other six Te chains, and is combined into a hexagonal structure by weak van der Waals forces. Te belongs to the non-centrosymmetric P21 space group, and this asymmetric center will lead to a bulk photovoltaic effect. The van der Waals tellurium grown by the preparation method of the present invention has high crystal quality and stronger spatial asymmetry, thereby exhibiting a more excellent bulk photovoltaic effect.

[0023] The present invention also provides a photoelectric device, comprising a van der Waals tellurium nanomaterial and metal electrodes at both ends of the van der Waals tellurium nanomaterial; the van der Waals tellurium nanomaterial is the van der Waals tellurium nanomaterial described in the above technical solution. The bulk photovoltaic effect of the photoelectric device has a wide spectrum, covering the ultraviolet band of 390nm to the mid-wave infrared band of 3.8μm; and the photoelectric device has a high current density in the communication band of 1.3μm, up to 70.4A·cm -2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a microstructure diagram of the van der Waals tellurium nanomaterial prepared in Example 1;

[0025] Figure 2 This is a particle size distribution diagram of the van der Waals tellurium nanomaterial prepared in Example 1;

[0026] Figure 3 This is a schematic diagram of the structure of the optoelectronic device described in Example 1;

[0027] Figure 4 is a current-voltage curve of the photoelectric device described in Example 1 in a dark state;

[0028] Figure 5 The photocurrent-time curve of the photoelectric device described in Example 1;

[0029] Figure 6 is the current-voltage curve of the photoelectric device described in Example 1;

[0030] Figure 7 Micro-area scanning photoelectric characterization of the photoelectric device described in Example 1 under a light source with a wavelength of 1.31 μm;

[0031] Figure 8 Micro-area scanning photoelectric characterization of the photoelectric device described in Example 1 under a light source with a wavelength of 1.55 μm;

[0032] Fig. 9The relationship between the photocurrent and the device channel position of the photoelectric device micro-area scanning photoelectric characterization described in Example 1;

[0033] Fig.10 The bulk photovoltaic response wavelength spectrum of the optoelectronic device described in Example 1;

[0034] Fig.11 The relationship between the 1.31 μm optical power density and the bulk photovoltaic response current of the optoelectronic device described in Example 1;

[0035] Fig.12 It is a schematic diagram of the structure of the optoelectronic device described in Example 2;

[0036] Fig.13 The micro-area scanning photoelectric characterization of the photoelectric device described in Example 2 under a light source with a wavelength of 830 nm;

[0037] Fig.14 Micro-area scanning photoelectric characterization of the photoelectric device described in Example 2 under a light source with a wavelength of 1.31 μm;

[0038] Fig.15 The micro-area scanning photoelectric characterization of the photocurrent and the device channel position of the photoelectric device described in Example 2;

[0039] Fig.16 is a graph of photocurrent versus time of the optoelectronic device described in Example 2 under 1.31 μm light irradiation;

[0040] Fig.17 is a graph of photocurrent versus time of the optoelectronic device described in Example 2 under 1.55 μm light irradiation;

[0041] Fig.18 This is an atomic force microscope characterization image of the van der Waals tellurium nanomaterial described in Example 1. DETAILED DESCRIPTION

[0042] The present invention provides a method for preparing a van der Waals tellurium nanomaterial, comprising the following steps:

[0043] Using selenium telluride as a raw material, chemical vapor deposition is performed on the surface of a substrate to obtain the van der Waals tellurium nanomaterial;

[0044] The chemical vapor deposition is performed under the condition of nitrogen flow.

[0045] In the present invention, unless otherwise specified, all preparation raw materials are commercially available products well known to those skilled in the art.

[0046] In the present invention, the van der Waals tellurium nanomaterial refers to a tellurium nanomaterial in which tellurium atoms form spiral chains and the chains are bonded by van der Waals forces.

[0047] In the present invention, the substrate preferably includes a silicon substrate, a glass substrate, a mica substrate or a sapphire substrate, and is more preferably a silicon substrate; the thickness of the substrate is preferably 500nm to 500μm, more preferably 500nm to 100μm, and most preferably 500nm to 10μm.

[0048] In the present invention, the substrate is preferably placed downstream of the quartz tube, and the selenium telluride is preferably placed in a ceramic boat at the center of the quartz tube.

[0049] Before the chemical vapor deposition, the present invention preferably performs air exhaust. The present invention has no special limitation on the process of air exhaust, and the process well known to those skilled in the art can be used to ensure that the ambient pressure is reduced to below 10Pa.

[0050] In the present invention, during the nitrogen flow process, the flow rate of nitrogen is preferably 30 to 80 sccm, more preferably 40 to 60 sccm, and most preferably 50 sccm.

[0051] In the present invention, the chemical vapor deposition is preferably carried out under heating conditions; the heating temperature is preferably 550-700°C, more preferably 580-680°C, and most preferably 600-650°C; the heating insulation time is preferably 20-60min, more preferably 30-50min, and most preferably 30-40min.

[0052] After the chemical vapor deposition is completed, the present invention also preferably includes cooling. The present invention does not have any special limitation on the cooling process, and the cooling process can be carried out using a process well known to those skilled in the art.

[0053] The present invention also provides a van der Waals tellurium nanomaterial prepared by the preparation method described in the above technical solution. The van der Waals tellurium nanomaterial has a length of 3.73 to 12.28 μm and a thickness of less than 200 nm.

[0054] The present invention also provides the application of the van der Waals tellurium nanomaterial described in the above technical solution in optoelectronic devices.

[0055] The present invention also provides a photoelectric device, comprising a van der Waals tellurium nanomaterial and metal electrodes at both ends of the van der Waals tellurium nanomaterial;

[0056] The van der Waals tellurium nanomaterial is the van der Waals tellurium nanomaterial described in the above technical solution.

[0057] In the present invention, the distance between the metal electrodes at both ends of the van der Waals tellurium nanomaterial is preferably 2.5 to 14.5 μm, more preferably 3.7 to 6.8 μm; the width of the van der Waals tellurium nanomaterial is preferably 0.2 to 7.8 μm, more preferably 0.32 to 2 μm.

[0058] In the present invention, the material of the metal electrode is preferably one or more of gold, platinum and palladium, more preferably gold. In the present invention, the thickness of the metal electrode is preferably 80 to 200 nm, more preferably 90 to 120 nm, and most preferably 100 nm.

[0059] The present invention also provides a method for preparing the optoelectronic device described in the above technical solution, comprising the following steps:

[0060] After coating photoresist on a substrate having a van der Waals tellurium nanomaterial on its surface, a van der Waals tellurium nanomaterial is selected, and electron beam lithography and development are performed in sequence until positions for preparing electrodes are exposed at both ends of the selected van der Waals tellurium nanomaterial, and then electrodes are evaporated and the photoresist is removed to obtain the optoelectronic device.

[0061] In the present invention, the preparation process of the substrate having the van der Waals tellurium nanomaterial on the surface is preferably to transfer the van der Waals tellurium nanomaterial prepared on the substrate surface by the preparation method described in the above technical solution to the surface of the SiO2 / Si substrate. The SiO2 / Si substrate preferably includes a silicon substrate and a silicon dioxide layer on the surface of the silicon substrate. The van der Waals tellurium nanomaterial is preferably transferred to the surface of the silicon dioxide layer. The present invention does not have any special limitation on the transfer method, and the method well known to those skilled in the art can be used.

[0062] In the present invention, the photoresist is preferably PMMA photoresist, and the thickness of the photoresist is preferably 300-700 nm, more preferably 500 nm. The present invention does not have any special limitation on the coating process, and the process well known to those skilled in the art can be used.

[0063] In the present invention, the method of selecting a van der Waals tellurium nanomaterial is preferably to select it using a microscope. The length of the selected van der Waals tellurium nanomaterial is preferably 3 to 120 μm.

[0064] The present invention does not have any special limitation on the process of electron beam lithography and development, and the process well known to those skilled in the art can be used.

[0065] In the present invention, the thickness of the metal electrode is preferably 80-200 nm, more preferably 90-120 nm, and most preferably 100 nm. The present invention does not have any special limitation on the evaporation process, and the process well known to those skilled in the art can be used.

[0066] In the present invention, the process of removing the photoresist is preferably performed by immersing in an acetone solution; the immersion time is preferably 3 to 15 minutes, more preferably 3 to 8 minutes, and most preferably 5 minutes.

[0067] The van der Waals tellurium nanomaterial with wide-band bulk photovoltaic response, its preparation method and application, optoelectronic device and its preparation method provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0068] Example 1

[0069] Selenium telluride is placed as a raw material in a ceramic boat at the center of a quartz tube, a 500 nm thick silicon substrate is placed downstream of the quartz tube, and then the air in the quartz tube is exhausted until the pressure of the quartz tube drops below 10 Pa, nitrogen is introduced at a flow rate of 50 sccm, and the tube is heated to 650° C. and kept warm for 30 minutes. After natural cooling, van der Waals tellurium nanomaterials are obtained on the surface of the Si substrate;

[0070] The van der Waals tellurium nanomaterial on the surface of the Si substrate was transferred to a silicon substrate with a 280nm thick silicon dioxide layer on the surface, and then a layer of PMMA photoresist with a thickness of 500nm was thrown off. The van der Waals tellurium nanomaterial with a length of 9.68μm was found under a microscope. After electron beam lithography and development process, the position of the evaporated electrode (located at both ends of the van der Waals tellurium nanomaterial) was exposed. Gold electrodes with a thickness of 100nm were evaporated by thermal evaporation to overlap the two ends of the van der Waals tellurium nanomaterial. The gold electrodes were soaked in an acetone solution for 5min, and the PMMA glue was removed to obtain a photoelectric device (structure as shown in FIG. Figure 3 As shown, the channel length (the distance between the two gold electrodes) of the optoelectronic device is 6.1 μm, and the width (the width of the van der Waals tellurium nanomaterial) is 2.8 μm);

[0071] The van der Waals tellurium nanomaterial was subjected to a microscope test, and the test results were as follows: Figures 1-2 As shown, Figure 1 is a microstructure diagram of the van der Waals tellurium nanomaterial, Figure 2 is the particle size distribution diagram of the van der Waals tellurium nanomaterial, Figures 1-2 It can be seen that the van der Waals tellurium nanomaterial is a rod-like structure, the length of which is mainly distributed in the range of 3.73 to 12.28 μm, and the average length is 5.19 μm;

[0072] The van der Waals tellurium nanomaterials were characterized by atomic force microscopy. The test results are as follows: Fig.18 As shown by Fig.18 It can be seen that the thickness of the van der Waals tellurium nanomaterial is 198.2 nm.

[0073] The current-voltage curve of the photoelectric device in the dark state is tested. The test results are as follows: Figure 4 As shown by Figure 4 It can be seen that the current-voltage characteristics of the photoelectric device indicate that a good ohmic contact is formed between gold and tellurium;

[0074] The photoelectric device is subjected to photoelectric characterization. The voltage applied to the electrodes at both ends of the photoelectric device is zero volt. First, a photocurrent and time test is performed. The test results are as follows: Figures 5-6 As shown, Figure 5 is the photocurrent-time curve of the photoelectric device, Figure 6 is the current-voltage curve of the photoelectric device; Figure 5 It can be seen that under 1.31μm light, a stable photocurrent can be generated quickly, and the generated photocurrent is as high as tens of microamperes. When the light power is from 157mW / mm 2 Change to 3.5mW / mm 2 , the photocurrent gradually decreases; Figure 6 It can be seen that under dark conditions, the current-voltage curve of the van der Waals tellurium photoelectric device passes through the origin. As the power density of the incident light increases, the short-circuit current and the open-circuit voltage increase and deviate from the origin. This non-zero characteristic may be attributed to the photovoltaic effect, but this linear characteristic of the photoelectric device is very different from the exponential curve observed in the pn junction device (the curve formula is I = I0 [exp (qV / kT) -1], which is an e exponential relationship);

[0075] The photoelectric device was subjected to micro-area scanning photoelectric characterization. The voltage applied to the electrodes at both ends of the photoelectric device was zero volt. The wavelength of the test light source was 1.31 μm and 1.55 μm, and the power density was 1.64 and 0.65 mW / mm respectively. 2 .in Figure 7 The photoelectric characterization of the photoelectric device by micro-area scanning under a light source with a wavelength of 1.31 μm is performed. Figure 8 The photoelectric device is characterized by micro-area scanning photoelectricity at a light source with a wavelength of 1.55 μm. Figures 7-8 It can be seen that a larger photocurrent is observed in the channel of the optoelectronic device rather than in the interface region where the electrode contacts the tellurium nanomaterial;

[0076] Fig. 9 The relationship between the photocurrent and the device channel position of the micro-area scanning photoelectric characterization of the photoelectric device is given by Fig. 9 It can be seen that when the micro-area infrared light starts to move from one end contact electrode and moves away from the contact electrode, the photocurrent represented gradually increases and almost reaches the maximum in the middle of the channel of the photoelectric device. When the micro-area infrared light approaches the other end contacting the single electrode, the photocurrent gradually decreases; the micro-area scanning photoelectric characterization results exclude other photoelectric effects, and the photoelectric device has a bulk photovoltaic effect;

[0077] The photoelectric device is subjected to Fourier photocurrent characterization, and the voltage applied to the electrodes at both ends of the photoelectric device is zero volt. The characterization results are as follows Figures 10-11 As shown, Fig.10 is the bulk photovoltaic response wavelength spectrum of the optoelectronic device, Fig.11 is the relationship between the 1.31 μm optical power density and the bulk photovoltaic response current of the optoelectronic device; Fig.10 It can be seen that the optoelectronic device has a very wide photovoltaic response band, covering the ultraviolet band of 390nm to the mid-wave infrared band of 3.8μm; it is similar to the reported semiconductors (MoS2, WS2, PZTO lead zirconate titanate, OMPH (perovskite-type organometallic halide), MPI (MAPbI3), KBNNO ([KNbO3] 1-x [BaNi 1 / 2 Nb 1 / 2 O 3-δ ] x Compared with the ultraviolet and visible light spectral ranges observed in BFO (BiFeO3), BFCO (Bi2FeCrO6), and BTO (barium titanate), the bulk photovoltaic response band of the optoelectronic device is significantly broadened. Fig.11 It can be seen that the bulk photovoltaic effect of the optoelectronic device has a high current density of 70.4A·cm in the communication band of 1.3μm. -2 The photocurrent density of the photovoltaic response of optoelectronic devices within the infrared communication band is not only comparable to the photoelectric density of current ultraviolet and visible light materials, but also exceeds the photocurrent generated by mid-wave infrared semi-metals.

[0078] Example 2

[0079] Selenium telluride is placed as a raw material in a ceramic boat at the center of a quartz tube, a 500 nm thick silicon substrate is placed downstream of the quartz tube, and then the air in the quartz tube is exhausted until the pressure of the quartz tube drops below 10 Pa, nitrogen is introduced at a flow rate of 50 sccm, and the tube is heated to 650° C. and kept warm for 30 minutes. After natural cooling, van der Waals tellurium nanomaterials are obtained on the surface of the Si substrate;

[0080] The van der Waals tellurium nanomaterial on the surface of the Si substrate was transferred to a silicon substrate with a 280nm thick silicon dioxide layer on the surface, and then a layer of PMMA photoresist with a thickness of 500nm was thrown off. The van der Waals tellurium nanomaterial with a length of 11.68μm was found under a microscope. After electron beam lithography and development process, the position of the evaporated electrode (located at both ends of the van der Waals tellurium nanomaterial) was exposed. Gold electrodes with a thickness of 100nm were evaporated by thermal evaporation to overlap the two ends of the van der Waals tellurium nanomaterial. The gold electrodes were soaked in an acetone solution for 5min, and the PMMA glue was removed to obtain a photoelectric device (structure as shown in FIG. Fig.12 As shown, the channel length (the distance between the two gold electrodes) of the optoelectronic device is 3.8 μm, and the width (the width of the van der Waals tellurium nanomaterial) is 0.23 μm);

[0081] The photoelectric device was subjected to micro-area scanning photoelectric characterization. The voltage applied to the electrodes at both ends of the photoelectric device was zero volt. The wavelength of the test light source was 830 nm and 1.31 μm, and the power density was 0.12 mW / mm 2 and 0.04mW / mm 2 .in Fig.13 The photoelectric characterization of the photoelectric device by micro-area scanning under a light source with a wavelength of 830 nm is performed. Fig.14 The photoelectric device is characterized by micro-area scanning photoelectricity at a light source with a wavelength of 1.31 μm. Figures 13-14 It can be seen that a larger photocurrent is observed in the channel of the optoelectronic device rather than in the interface region where the electrode contacts the tellurium nanomaterial;

[0082] Fig.15 The micro-area scanning photoelectric characterization of the photocurrent and the device channel position relationship of the photoelectric device is Fig.15 It can be seen that when the micro-area infrared light moves from one end contact electrode and moves away from the contact electrode, the photocurrent gradually increases and almost reaches the maximum in the middle of the photoelectric device channel. When the micro-area infrared light approaches the other end contact single pole, the photocurrent gradually decreases; the micro-area scanning photoelectric characterization results show that the channel length is 3.8μm and the width is 0.23μm. Van der Waals tellurium nanomaterials also have bulk photovoltaic effect;

[0083] The photoelectric device is subjected to Fourier photocurrent characterization, and the voltage applied to the electrodes at both ends of the photoelectric device is zero volt. The characterization results are as follows Figures 16-17 As shown, Fig.16 is a graph of photocurrent versus time under 1.31 μm light irradiation. Fig.17 is a graph of photocurrent versus time under 1.55 μm light irradiation, Figures 16-17 It can be seen that under the irradiation of 1.31μm and 1.55μm light, the optical power increases from 17mW / mm 2 Change to 125mW / mm 2 and from 35.1mW / mm 2 Change to 99.5mW / mm 2 , the device can quickly generate a stable photocurrent, with the generated photocurrent reaching several hundred nanoamperes.

[0084] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a van der Waals tellurium nanomaterial, characterized in that: The following steps are involved: Using selenium telluride as a raw material, chemical vapor deposition is performed on the surface of a substrate to obtain the van der Waals tellurium nanomaterial; The chemical vapor deposition is performed under the condition of nitrogen flow.

2. The preparation method according to claim 1, characterized in that The substrate includes a silicon substrate, a glass substrate, a mica substrate or a sapphire substrate; The thickness of the substrate is 500nm-500μm.

3. The preparation method according to claim 1, characterized in that: During the nitrogen flow, the flow rate of nitrogen is 30-80 sccm.

4. The preparation method according to claim 1, characterized in that: The chemical vapor deposition is carried out under heating conditions; The heating temperature is 550-700° C., and the heat preservation time is 20-60 minutes.

5. The van der Waals tellurium nanomaterial prepared by the preparation method according to any one of claims 1 to 4, characterized in that: The length of the van der Waals tellurium nanomaterial is 3.73-12.28 μm, and the thickness is less than 200 nm.

6. Use of the van der Waals tellurium nanomaterial according to claim 5 in optoelectronic devices.

7. A photoelectric device, characterized in that: It includes a van der Waals tellurium nanomaterial and metal electrodes at both ends of the van der Waals tellurium nanomaterial; The van der Waals tellurium nanomaterial is the van der Waals tellurium nanomaterial according to claim 5.

8. The optoelectronic device according to claim 7, characterized in that The distance between the metal electrodes at both ends of the van der Waals tellurium nanomaterial is 2.5 to 14.5 μm; The width of the van der Waals tellurium nanomaterial is 0.2-7.8 μm.

9. The optoelectronic device according to claim 7, characterized in that: The material of the metal electrode is one or more of gold, platinum and palladium.

10. The method for preparing a photoelectric device according to any one of claims 7 to 9, characterized in that: The following steps are involved: After coating photoresist on a substrate having a van der Waals tellurium nanomaterial on its surface, a van der Waals tellurium nanomaterial is selected, and electron beam lithography and development are performed in sequence until positions for preparing electrodes are exposed at both ends of the selected van der Waals tellurium nanomaterial, and then electrodes are evaporated and the photoresist is removed to obtain the optoelectronic device.

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