Van der Waals tellurium nanomaterial with broad-spectrum bulk photovoltaic response, preparation method and application thereof, optoelectronic device and preparation method thereof

Abstract

The present invention relates to the field of optoelectronic materials and devices, and in particular to a van der Waals tellurium nanomaterial with a bulk photovoltaic response, its preparation method and application, and optoelectronic devices and their preparation methods. 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, 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 nitrogen flow conditions. The van der Waals tellurium nanomaterial prepared by this method can enable optoelectronic devices to exhibit a broad bulk photovoltaic response spectrum 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 broad-spectrum bulk photovoltaic response, a preparation method and application thereof, and a 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 a hot topic of intense research due to its great potential in overcoming the inherent Shockley-Queisser effect limit in conventional pn junction photovoltaics. Initially, studies on ferroelectric oxide materials (such as LiNbO3, BaTiO3, and Pb(Zr)) have been conducted. 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 research has 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 have demonstrated outstanding bulk photovoltaic effects. For example, in-plane tensile strain breaks the inversion symmetry of rhombohedral MoS2, generating a high current density of up to 10A·cm under 630nm light. -2 Bulk photovoltaic response current. Due to interband optical transitions in semiconductors and heterostructures, bulk photovoltaic response is currently limited to a limited wavelength range from the ultraviolet to the visible. Although Berry curvature and scattering in semimetals can produce mid-wave infrared bulk photovoltaic response, the low probability of photoelectric transitions generated by polarized single-wavelength lasers leads to a significant decrease in the photocurrent density of the bulk photovoltaic response at the same optical power. Therefore, achieving a bulk photovoltaic response with a broad spectral range and high photocurrent density is a challenge that needs to be addressed. Summary of the Invention

[0003] The present invention aims to provide a van der Waals tellurium nanomaterial with a broad spectral bulk photovoltaic response, a preparation method and application thereof, and a photovoltaic device and a preparation method thereof. The van der Waals tellurium nanomaterial prepared by the preparation method can enable the photovoltaic device to have a broad spectral bulk photovoltaic response and a 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 nitrogen flow conditions.

[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 500 nm to 500 μm.

[0010] Preferably, during the nitrogen flow process, the flow rate of nitrogen is 30 to 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 to 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. 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 nitrogen conditions. Because 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 six other Te chains, and is bound 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 photoelectric device has a broad spectral range, covering the ultraviolet band of 390nm to the mid-wave infrared band of 3.8μm; and the photoelectric device has a high current density of up to 70.4A·cm in the communication band of 1.3μm. -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 structural diagram of the optoelectronic device described in Example 1;

[0027] Figure 4 is the current-voltage curve of the photoelectric device described in Example 1 in the 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] Figure 9The relationship between the photocurrent and the device channel position of the micro-area scanning photoelectric characterization of the optoelectronic device described in Example 1;

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

[0034] Figure 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] Figure 12 This is a schematic structural diagram of the optoelectronic device described in Example 2;

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

[0037] Figure 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] Figure 15 The micro-area scanning photoelectric characterization of the photocurrent and device channel position of the photoelectric device described in Example 2;

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

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

[0041] Figure 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 nitrogen flow conditions.

[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, 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 evacuation. The present invention does not have any special restrictions on the process of evacuating air, and the process can be performed using a process well known to those skilled in the art and ensuring that the ambient pressure is reduced to below 10 Pa.

[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 holding time is preferably 20-60 min, more preferably 30-50 min, and most preferably 30-40 min.

[0052] After the chemical vapor deposition is completed, the present invention preferably further includes cooling. The present invention does not have any special limitation on the cooling process, and the cooling process can be performed 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. Then, electrodes are evaporated and the photoresist is removed to obtain the optoelectronic device.

[0061] In the present invention, the process for preparing the substrate having the van der Waals tellurium nanomaterial on its surface is preferably to transfer the van der Waals tellurium nanomaterial prepared on the substrate surface using the preparation method described in the above technical solution to the surface of a SiO2 / Si substrate. The SiO2 / Si substrate preferably comprises 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 impose any particular restrictions on the transfer method, and methods 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 to 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 performed 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 can be performed using a process well known to those skilled in the art.

[0065] 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. The present invention does not have any particular limitation on the evaporation process, and any 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 soaking in an acetone solution; the soaking 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 a broad-spectrum bulk photovoltaic response, its preparation method and application, and the optoelectronic device and its preparation method provided by the present invention are described in detail below with reference to the embodiments. However, these should not be construed as limiting the scope of protection of the present invention.

[0068] Example 1

[0069] Selenium telluride as a raw material is placed in a ceramic boat at the center of a quartz tube. A 500nm thick silicon substrate is placed downstream of the quartz tube. The air in the quartz tube is then exhausted until the pressure in the quartz tube drops below 10Pa. Nitrogen gas is then introduced at a flow rate of 50sccm. 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. 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 was exposed (located at both ends of the van der Waals tellurium nanomaterial). 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 acetone solution for 5 minutes, 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 tested under a microscope, 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 with a length mainly distributed in the range of 3.73 to 12.28 μm and an average length of 5.19 μm.

[0072] The van der Waals tellurium nanomaterials were characterized by atomic force microscopy, and the test results were as follows: Figure 18 As shown by Figure 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 two electrodes of the photoelectric device is zero volt. First, the photocurrent and time are tested. 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 the illumination of 1.31μm, 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 open-circuit voltage increase simultaneously 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 pn junction devices (the curve formula is I = I0 [exp(qV / kT)-1], which is an 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 Micro-area scanning photoelectric characterization of the photoelectric device at a light source with a wavelength of 1.31 μm, Figure 8 The photoelectric device is characterized by micro-area scanning 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 between the electrode and the tellurium nanomaterial;

[0076] Figure 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 Figure 9 As can be seen, as the micro-area infrared light moves from one end contact electrode and away from the contact electrode, the photocurrent gradually increases, reaching a maximum almost in the middle of the optoelectronic device channel. As the micro-area infrared light approaches the other end contacting the single electrode, the photocurrent gradually decreases. The micro-area scanning photoelectric characterization results rule out other photoelectric effects, and the optoelectronic device exhibits a bulk photovoltaic effect.

[0077] The photoelectric device was subjected to Fourier photocurrent characterization, and the voltage applied to the electrodes at both ends of the photoelectric device was zero volt. The characterization results are as follows Figures 10-11 As shown, Figure 10 is the bulk photovoltaic response wavelength spectrum of the optoelectronic device, Figure 11 is the relationship between the 1.31 μm optical power density and the bulk photovoltaic response current of the photoelectric device; Figure 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; and compared with 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 spectrum ranges observed in BFO (BiFeO3), BFCO (Bi2FeCrO6), and BTO (barium titanate), the bulk photovoltaic response band of the optoelectronic device is significantly broadened. Figure 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 bulk photovoltaic response photocurrent density of optoelectronic devices within the infrared communication band is not only comparable to that 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 as a raw material is placed in a ceramic boat at the center of a quartz tube. A 500nm thick silicon substrate is placed downstream of the quartz tube. The air in the quartz tube is then exhausted until the pressure in the quartz tube drops below 10Pa. Nitrogen gas is then introduced at a flow rate of 50sccm. 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. 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 was exposed (located at both ends of the van der Waals tellurium nanomaterial). 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 acetone solution for 5min, and the PMMA glue was removed to obtain a photoelectric device (structure as shown in FIG). Figure 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 Figure 13 The photoelectric characterization of the photoelectric device by micro-area scanning under a light source with a wavelength of 830 nm is performed. Figure 14 The photoelectric device is characterized by micro-area scanning 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 between the electrode and the tellurium nanomaterial;

[0082] Figure 15 The micro-area scanning photoelectric characterization of the photocurrent and the device channel position relationship of the photoelectric device is Figure 15 As can be seen, when the micro-area infrared light moves from one end contact electrode and away from the contact electrode, the photocurrent gradually increases, reaching a maximum almost in the middle of the optoelectronic device channel. When the micro-area infrared light approaches the other end contact single electrode, the photocurrent gradually decreases. 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 a bulk photovoltaic effect.

[0083] The photoelectric device was subjected to Fourier photocurrent characterization, and the voltage applied to the electrodes at both ends of the photoelectric device was zero volt. The characterization results are as follows Figures 16-17 As shown, Figure 16 This is a graph of photocurrent versus time under 1.31 μm light irradiation. Figure 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, and the generated photocurrent is as high as 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 principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. Application of a van der Waals tellurium nanomaterial in an optoelectronic device, characterized in that: The method for preparing the van der Waals tellurium nanomaterial comprises the following steps: 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 carried out under nitrogen conditions; During the nitrogen process, the nitrogen flow rate was 30 ~ 80sccm; The van der Waals tellurium nanomaterial has a rod-like structure; The chemical vapor deposition is carried out under heating conditions; The heating temperature is 650° C. and the holding time is 30 minutes.

2. The use 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 500 nm to 500 μm.

3. The use according to claim 1 or 2, characterized in that The van der Waals tellurium nanomaterial has a length of 3.73 to 12.28 μm and a thickness of less than 200 nm.

4. 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 method for preparing the van der Waals tellurium nanomaterial comprises the following steps: 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 carried out under nitrogen conditions; During the nitrogen process, the nitrogen flow rate was 30 ~ 80sccm; The van der Waals tellurium nanomaterial has a rod-like structure; The chemical vapor deposition is carried out under heating conditions; The heating temperature is 650° C. and the holding time is 30 minutes.

5. The optoelectronic device according to claim 4, wherein The distance between the metal electrodes at both ends of the van der Waals tellurium nanomaterial is 2.5-14.5 μm; The width of the van der Waals tellurium nanomaterial is 0.2-7.8 μm.

6. The optoelectronic device according to claim 4, wherein The material of the metal electrode is one or more of gold, platinum and palladium.

7. The method for preparing a photoelectric device according to any one of claims 4 to 6, 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. Then, electrodes are evaporated and the photoresist is removed to obtain the optoelectronic device.

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