Photoelectric detector based on erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction

Abstract

The invention relates to the field of manufacturing of optoelectronic devices, in particular to a photoelectric detector based on an erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction, and a manufacturing method of the photoelectric detector comprises the following steps: growing an erbium-phosphorus co-doped WS2 material on a silicon wafer with an H bond attached on the surface by adopting a normal-pressure chemical vapor deposition method to obtain an erbium-phosphorus co-doped WS2 material sample; spin-coating a photoresist on an erbium-phosphorus co-doped WS2 material sample, fixing the sample, and reserving an electrode pattern on the sample through laser direct writing and developing operation; and coating a film on the reserved electrode pattern by adopting a magnetron sputtering technology, and carrying out photoresist removal operation on a coated sample to obtain the photoelectric detector based on the erbium-phosphorus co-doped WS2 / Si2H Van der Waals heterojunction. By constructing the WS2 / Si2H van der Waals heterojunction, the problem of lattice matching generally existing in a traditional epitaxial layered semiconductor is solved, and the optical frequency response range of the photoelectric detector is expanded by doping materials.

Description

Technical Field

[0001] The present invention relates to the field of optoelectronic device manufacturing, and particularly to a photodetector based on an erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction. Background Art

[0002] In an epitaxial layered semiconductor, atoms are arranged in a certain periodic pattern to form a lattice. When two different materials come into contact, if there is a large difference in their lattice constants or different lattice structures, lattice mismatch will occur. WS2 is a kind of epitaxial layered semiconductor material and belongs to the family of transition metal dichalcogenides (TMDCs), with a typical layered structure. It has attracted wide attention due to its direct bandgap of 1.8 eV, wide light absorption range, and strong light absorption efficiency, and has great potential in the application direction of photodetectors.

[0003] Limited by current calculation methods and the computing performance of supercomputers, computers cannot accurately obtain the solutions of the Schrödinger equation for complex systems. The research and application of epitaxial layered semiconductors in the prior art are limited. Summary of the Invention

[0004] In view of this, the present invention discloses a photodetector based on an erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction to solve the above problems. The photodetector uses an erbium-phosphorus co-doped WS2 material as the light absorption layer of the photodetector. The fabrication of the photodetector includes:

[0005] Using atmospheric pressure chemical vapor deposition method, grow an erbium-phosphorus co-doped WS2 material on a silicon wafer with H bonds on its surface to obtain an erbium-phosphorus co-doped WS2 material sample; spin-coat a photoresist on the erbium-phosphorus co-doped WS2 material sample and fix it, and reserve electrode patterns on the sample through laser direct writing and development operations; use magnetron sputtering technology to coat the reserved electrode patterns, and perform a degumming operation on the coated sample to obtain a photodetector based on an erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction.

[0006] The beneficial effects of the present invention include: By using WS2 and Si to construct a WS2 / Si2H van der Waals heterojunction, the lattice matching problem commonly existing in traditional epitaxial layered semiconductors is avoided; By attaching hydrogen bonds to the surface of the silicon wafer, the surface stability of the silicon wafer is further improved, the influence of environmental changes on the silicon wafer surface is buffered, making the van der Waals heterojunction more stable, and thus enhancing the anti-interference ability and long-term stability of the photodetector; By the way of erbium and phosphorus co-doping, the problem of defects existing in the WS2 / Si2H van der Waals heterojunction is further solved, the carrier mobility of the WS2 / Si2H van der Waals heterojunction is improved, the energy band structure is regulated, the light absorption ability is enhanced, and the absorption spectrum of the photodetector based on this material is broadened; The present invention not only introduces a reliable and promising photodetector based on erbium and phosphorus co-doped WS2 / Si2H van der Waals heterojunction, but also provides a solution idea for the lattice matching problem of epitaxial layered semiconductors. Description of the Drawings

[0007] Figure 1 It is the atomic structure diagram of erbium and phosphorus co-doped WS2 / Si2H in the embodiment of the present invention, where (a) is the atomic structure diagram of WS2 / Si2H, (b) is the atomic structure diagram of WS2(Er) / Si2H(P), and (c) is the atomic structure diagram of WS2(2Er) / Si2H(P);

[0008] Figure 2 It is the electronic property of erbium and phosphorus co-doped WS2 / Si2H in the embodiment of the present invention, where (d) is the test result of the thermodynamic stability of WS2 / Si2H, (e) is the test result of the thermodynamic stability of WS2(Er) / Si2H(P), (f) is the test result of the thermodynamic stability of WS2(2Er) / Si2H(P), and (g) is the test result of the layer spacing of WS2 / Si2H;

[0009] Figure 3 It is the average electrostatic potential diagram of erbium and phosphorus co-doped WS2 / Si2H in the embodiment of the present invention, where (a) is the average electrostatic potential diagram of WS2 / Si2H, (b) is the average electrostatic potential diagram of WS2(Er) / Si2H(P), (c) is the average electrostatic potential diagram of WS2(2Er) / Si2H(P), (d) is the bader charge diagram of WS2 / Si2H, (e) is the bader charge diagram of WS2(Er) / Si2H(P), and (f) is the bader charge diagram of WS2(2Er) / Si2H(P);

[0010] Figure 4Charge density maps of Er and P co-doped WS2 / Si2H in the embodiments of the present invention, where (a) is the planar average charge density difference map of WS2 / Si2H, (b) is the planar average charge density difference map of WS2(Er) / Si2H(P), (c) is the planar average charge density difference map of WS2(2Er) / Si2H(P), (d) is the differential charge density map of WS2 / Si2H, (e) is the differential charge density map of WS2(Er) / Si2H(P), and (f) is the differential charge density map of WS2(2Er) / Si2H(P);

[0011] Figure 5 Schematic diagram of the electric field direction regulated by an external electric field in the embodiments of the present invention;

[0012] Figure 6 Optical absorption coefficients of Er and P co-doped WS2 / Si2H at different wavelengths in the embodiments of the present invention;

[0013] Figure 7 Optical absorption coefficients of Er and P co-doped WS2 / Si2H at different wavelengths after being regulated by applying different voltages in the embodiments of the present invention, where (a) is the optical absorption coefficient when different positive voltages are applied to WS2 / Si2H, (b) is the optical absorption coefficient when different negative voltages are applied to WS2 / Si2H, (c) is the optical absorption coefficient when different positive voltages are applied to WS2(Er) / Si2H(P), and (d) is the optical absorption coefficient when different negative voltages are applied to WS2(Er) / Si2H(P);

[0014] Figure 8 Optical absorption coefficients of WS2(2Er) / Si2H(P) at different wavelengths after being regulated by applying different voltages, (e) is the optical absorption coefficient when different positive voltages are applied to WS2(2Er) / Si2H(P), and (f) is the optical absorption coefficient when different negative voltages are applied to WS2(2Er) / Si2H(P). Detailed implementation manners

[0015] In order to make the objectives, technical solutions, features, and advantages of the present invention clearer and more understandable, the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0016] Embodiment 1. This embodiment includes a photodetector based on an Er and P co-doped WS2 / Si2H van der Waals heterojunction. The Er and P co-doped WS2 material is used as the light absorption layer of the photodetector, and the WS2 layer and the Si2H layer form a van der Waals heterojunction.

[0017] The fabrication of the photodetector includes: growing erbium- and phosphorus-codoped WS2 material on a silicon wafer with H bonds on its surface by atmospheric pressure chemical vapor deposition to obtain an erbium- and phosphorus-codoped WS2 material sample; spin-coating and fixing photoresist on the erbium- and phosphorus-codoped WS2 material sample, and reserving electrode patterns on the sample through laser direct writing and development operations; coating the reserved electrode patterns by magnetron sputtering technology, and performing a degluing operation on the coated sample to obtain a photodetector based on erbium- and phosphorus-codoped WS2 / Si2H van der Waals heterojunction.

[0018] Further, the preparation of the silicon wafer with H bonds on its surface includes:

[0019] Step 1: Place the silicon wafer with its rough side facing up on a laser cutting workbench, clean the cut silicon wafer, and store the cleaned silicon wafer in absolute ethanol.

[0020] Specifically, in this embodiment, the set scanning pattern of the laser is a rectangle of 1.2 cm × 2.2 cm.

[0021] Further, the cleaning of the cut silicon wafer includes: placing the cut silicon wafer on a wafer washing rack, placing the wafer washing rack with the silicon wafer in a clean beaker, placing the beaker in an ultrasonic cleaner, and using different solvents to wash the silicon wafer multiple times.

[0022] Preferably, the cleaning solvents are sequentially deionized water, absolute ethanol, acetone, and isopropanol, and the cleaning time is set to 10 minutes. Among them, deionized water is used to initially remove the water-soluble impurities on the silicon wafer surface, absolute ethanol is used to remove organic impurities and hydrophilic impurities, acetone is used to remove organic matter impurities and hydrophobic impurities, and isopropanol is used to further remove the organic impurities on the silicon wafer surface and remove the acetone remaining from the previous cleaning step.

[0023] Further, the performance of the device formed after attaching hydrogen bonds to the silicon wafer surface is more stable and has better predictability.

[0024] Step 2: Take out the silicon wafer from absolute ethanol, use high-purity nitrogen to blow off the absolute ethanol on the silicon wafer surface, and immerse the silicon wafer in a BOE (Buffered Oxide Etch) solution to obtain a silicon wafer with H bonds on its surface.

[0025] Specifically, in the BOE solution, HF:NH4F = 1:9, and the soaking time of the silicon wafer is 5 - 10 minutes.

[0026] Further, the growth of erbium- and phosphorus-codoped WS2 material on a silicon wafer with H bonds on its surface by atmospheric pressure chemical vapor deposition method includes: preparing two quartz boats, cleaning them with anhydrous ethanol respectively; evenly spreading 500 mg of sublimed sulfur powder in the first quartz boat; mixing 60 mg of tungsten trioxide powder, 5 mg of erbium chloride powder and 3 mg of sodium chloride powder evenly, and spreading the mixed powder evenly in the second quartz boat; taking out a silicon wafer with H bonds on its surface, drying the surface of the silicon wafer with high-purity nitrogen, and placing the polished surface of the silicon wafer with H bonds downward on the second quartz boat; placing the two quartz boats in a tube furnace for reaction, taking out the quartz boats from the tube furnace after the reaction ends, and taking out the silicon wafer to obtain a WS2(Er) / Si2H(P) sample.

[0027] Specifically, the tube furnace includes a two-inch quartz tube with openings at both ends. Push the second quartz boat to the high-temperature zone of the quartz tube, and place the first quartz boat in the low-temperature zone 25 cm away from the high-temperature zone. After placing the two quartz boats, use a flange ring to tighten both ends of the quartz tube for subsequent operations. Tighten the inlet and outlet of both ends of the tube furnace, open the vacuum pump connected to the tube furnace to start pumping air. When the air pressure in the tube furnace drops to 1 Torr, close the vacuum pump and open the inlet, and introduce high-purity argon into the tube furnace at a flow rate of 1000 sccm to restore the air pressure in the tube furnace to atmospheric pressure, then close the inlet. Then open the vacuum pump again to start pumping air, and then open the inlet to restore atmospheric pressure again; perform such cyclic operations three times in total. When the atmospheric pressure is restored for the last time, adjust the argon flow rate at the inlet to 80 sccm, and open the outlet. The cyclic operation is used to remove the residual impurity gases in the tube. After the impurity gas removal operation is completed, heat up the tube furnace; preferably, the heating program is set as follows: set the high-temperature zone to rise from room temperature to the reaction temperature of 970 °C in 50 minutes, and keep it at 970 °C for 12 minutes, then stop heating and let the high-temperature zone cool naturally to room temperature; set the low-temperature zone to keep at room temperature for 30 minutes, rise to 220 °C in 20 minutes and keep it at 220 °C for 12 minutes, then stop heating and let the low-temperature zone cool naturally to room temperature. Further, when the high-temperature zone rises to 875 °C, replace the argon at the inlet with an argon-hydrogen mixture with a flow rate of 60 sccm and a volume ratio of 9:1. When it cools to 500 °C after the reaction ends, replace the argon-hydrogen mixture with argon with a flow rate of 100 sccm. After the tube furnace continues to cool to room temperature, close the inlet and outlet, take out the quartz boats from the tube furnace, and take out the silicon wafer to obtain a WS2(Er) / Si2H(P) sample.

[0028] Further, spin-coat and fix photoresist on the erbium- and phosphorus-codoped WS2 material sample, and reserve electrode patterns on the sample through laser direct writing and development operations, including:

[0029] Step 1, Spin-coating the support layer: Spin-coat a layer of LOR resist on the WS2(Er) / Si2H(P) sample using a spin coater. Set the rotation speed of the spin coater to 500 r / s for 5 s, and then set the speed to 3500 r / s for 35 s.

[0030] Step 2, Baking: Place the sample on a heating platform and set the temperature to 170 °C. Bake for 10 min. After baking, remove the sample and let it stand for 1 minute.

[0031] Step 3, Spin-coating photoresist: Use a spin coater to spin-coat another layer of S1805 photoresist on the first layer of resist. Set the rotation speed of the spin coater to 500 r / s for 5 s, and then set it to 2000 r / s for 25 s.

[0032] Step 4, Baking: Place the sample on another heating platform and set the temperature to 100 °C. Bake for 10 min. After baking, remove the sample and let it stand for 1 minute.

[0033] Step 5, Laser direct writing: Import the pre-drawn electrode pattern into the laser direct writing instrument. After selecting the area, execute the exposure command. The instrument uses ultraviolet light to deteriorate the photoresist for subsequent development operations.

[0034] Step 6, Development: Place the sample in AZ300MIF developer for 60 s. After completion, rinse the sample with deionized water and dry the surface moisture of the sample with high-purity nitrogen.

[0035] Furthermore, use magnetron sputtering technology to coat the reserved electrode pattern, and perform a degluing operation on the coated sample. The obtained photodetector based on the erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction includes:

[0036] Use a sputtering coater to coat the reserved electrode pattern. The metal electrodes used in this embodiment are chromium and gold, with thicknesses of 5 nm and 50 nm respectively. In this embodiment, acetone is used to remove the S1805 photoresist, and AZ300MIF developer is used to remove the LOR resist. Finally, place the sample in deionized water for cleaning, and blow off the surface moisture of the sample with high-purity nitrogen to obtain a photodetector based on the erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction.

[0037] Example 2, this example includes a photodetector based on an erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction. The erbium-phosphorus co-doped WS2 material is used as the light absorption layer of the photodetector, and the WS2 layer and the Si2H layer form a van der Waals heterojunction.

[0038] The difference from Example 1 is that in this example, the erbium chloride powder is 10 mg, and the WS2(2Er) / Si2H(P) sample is prepared by a tube furnace.

[0039] Furthermore, data analysis was carried out on erbium and phosphorus co-doped WS2 / Si2H, as Figure 1 shown in the atomic structure schematic diagram of erbium and phosphorus co-doped WS2 / Si2H. The ab initio molecular dynamics (AIMD) method was used to calculate the thermal stability of the van der Waals heterojunctions in WS2 / Si2H, WS2(Er) / Si2H(P), and WS2(2Er) / Si2H(P) at 300 K. It can be seen from Figure 2 that the energy oscillates slightly with the increase of time, and there is no obvious structural change, indicating that the structures of the three heterojunctions are relatively stable.

[0040] Furthermore, as Figure 3 shown, the work functions of the van der Waals heterojunctions of WS2 / Si2H, WS2(Er) / Si2H(P), and WS2(2Er) / Si2H(P) are respectively as Figure 3 shown, and their work functions are 4.466 eV, 6.1871 eV, and 6.5086 eV respectively. The Bader charge diagram can more clearly represent the electron transfer. It can be seen from the figure that in the WS2 / Si2H van der Waals heterojunction, 0.712|e| is transferred from the WS2 monolayer to the Si2H monolayer.

[0041] Furthermore, due to the different work functions of the WS2 and Si2H monolayers, electrons are transferred from WS2 to Si2H. Since the Si2H monolayer has a higher work function, when the WS2 monolayer is stacked on the Si2H monolayer, electrons can diffuse from WS2 to Si2H, and holes can diffuse from Si2H to WS2, further promoting the accumulation of electrons and holes in the Si2H monolayer and the WS2 monolayer. When one Er atom and one P atom are doped, 0.472|e| is transferred from the WS2 monolayer to the Si2H monolayer. When two Er atoms and one P atom are doped, 0.436|e| is transferred from the WS2 monolayer to the Si2H monolayer. The doping of Er increases the work function of the WS2 monolayer, while the doping of P decreases the work function of the Si2H monolayer, so the electron transfer from the WS2 monolayer to the Si2H monolayer is weakened. In summary, the charge transfer between the WS2 monolayer and the Si2H monolayer forms a built-in electric field, which promotes the boundary separation of photo-generated carriers and inhibits their recombination, thus enhancing the light absorption ability of the photodetector.

[0042] Furthermore, the charge redistribution and differential charge density at the van der Waals heterojunction interfaces of WS2 / Si2H, WS2(Er) / Si2H(P), and WS2(2Er) / Si2H(P) are as Figure 4 shown, Figure 4 in (a), (b), and (c) of , the accumulation of electrons is positive, while the consumption of electrons is negative;Figure 4 In (d), (e), and (f), electrons move from the WS2 monolayer to the Si2H monolayer. The WS2 monolayer loses electrons while the Si2H monolayer gains electrons.

[0043] Furthermore, carrier mobility is also a key parameter in electronic and optoelectronic devices. The carrier mobility was calculated using the deformation potential theory proposed by Bardeen and Shockley. The formula is as follows:

[0044]

[0045] where k B is the Boltzmann constant, T is the temperature, and 300 K was used in the calculation. m * is the effective mass in the transport direction, m d is the average effective mass of the carriers. E1 represents the deformation potential constant of holes located at the valence band maximum (VBM) or electrons concentrated at the conduction band minimum (CBM) along the transport direction. e is the electron charge, h is the reduced Planck constant, and C 2D is the elastic modulus of the uniformly deformed crystal.

[0046] Table 1. Effective mass, deformation potential constant, elastic modulus, and mobility of carriers in various directions of WS2 / Si2H, WS2(Er) / Si2H(P), and WS2(2Er) / Si2H(P) van der Waals heterojunctions

[0047]

[0048]

[0049] It can be seen from the table that the carrier mobility of the three heterojunctions is anisotropic in the x and y directions. The results show that when doped with one Er and one P, the WS2(Er) / Si2H(P) heterojunction has enhanced carrier mobility in both the x and y directions compared to the intrinsic WS2 / Si2H heterojunction. The hole mobility in the x direction is increased to 7920 cm 2 ·s -1 ·V -1 ; when the concentration of Er is increased, the WS2(2Er) / Si2H(P) heterojunction has lower carrier mobility in both the x and y directions compared to the WS2(Er) / Si2H(P) heterojunction. The reduction in carrier mobility in the x direction is smaller, while the reduction in the y direction is significant. However, compared to the WS2 / Si2H heterojunction, the overall carrier mobility is enhanced, and only the hole mobility in the y direction is reduced, further improving the sensitivity of the WS2 / Si2H van der Waals heterojunction material.

[0050] Furthermore, an external electric field in the vertical direction is adopted. The electronic properties of WS2 / Si2H, WS2(Er) / Si2H(P), and WS2(2Er) / Si2H(P) van der Waals heterojunctions are modulated. It is defined that the positive direction of the electric field is from the Si2H monolayer to the WS2 monolayer, as Figure 5 shown in the schematic diagram of the electric field direction regulated by the external electric field. Figure 6 Shown is the optical absorption coefficient of the material at different wavelengths without electric field regulation. Figure 7 , Figure 8 Shown is the optical absorption coefficient of the material at different wavelengths after applying the external electric field regulation. When an electric field is applied to the van der Waals heterojunction, the energy band structure and material properties can be deeply modulated. Figures 7, Figure 8 The absorption spectra in show that more detailed modulation is performed on the ultraviolet light band under the condition of an external electric field, thereby enhancing the infrared light absorption coefficient of the heterojunction. Strong ultraviolet light absorption and excellent hole mobility mean that the photodetector based on the erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction proposed in the present invention has good application prospects in the field of ultraviolet light detection. By doping with rare earth (Er), the energy band gap and infrared light absorption coefficient can be adjusted, making the heterojunction co-doped with Er and P have application value and application potential in the field of infrared optoelectronic devices.

[0051] Finally, it should be noted that the above only describes some embodiments of the present invention. For those skilled in the art, various changes, modifications, substitutions, and deformations of these embodiments can be conceived without departing from the principle and spirit of the present invention. The protection scope of the present invention is defined by the appended claims and their equivalents, and the above actions should all be covered within the protection scope of the present invention.

Claims

1. A photodetector based on erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction, characterized in that: The WS2 material co-doped with erbium and phosphorus is used as the light absorption layer of the photodetector, and the WS2 layer and the Si2H layer form a van der Waals heterojunction; the manufacturing method of the photodetector based on the WS2 / Si2H van der Waals heterojunction co-doped with erbium and phosphorus includes: An erbium-phosphorus co-doped WS2 material is grown on a silicon wafer with H bonds on the surface by atmospheric pressure chemical vapor deposition to obtain an erbium-phosphorus co-doped WS2 material sample; a photoresist is spin-coated on the erbium-phosphorus co-doped WS2 material sample and fixed, and an electrode pattern is reserved on the sample by laser direct writing and development operations; a magnetron sputtering technique is used to coat the reserved electrode pattern, and the coated sample is stripped to obtain a photodetector based on the erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction.

2. The photodetector based on erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction according to claim 1, characterized in that: Preparation of silicon wafers with H-bonds on the surface includes: Step 1, placing the silicon wafer with the rough surface facing upward on a laser cutting workbench for cutting, cleaning the cut silicon wafer, and storing the cleaned silicon wafer in anhydrous ethanol; Step 2: Take out the silicon wafer from the anhydrous ethanol, use high-purity nitrogen to blow away the anhydrous ethanol on the surface of the silicon wafer, and immerse the silicon wafer in a buffered oxide etching solution to obtain a silicon wafer with H bonds on the surface.

3. The photodetector based on erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction according to claim 2, characterized in that: The ratio of HF to NH4F in the buffered oxide etching solution is 1:9, and the immersion time of the silicon wafer in the buffered oxide etching solution is 5-10 minutes.

4. The photodetector based on erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction according to claim 1, characterized in that: The method of growing erbium-phosphorus co-doped WS2 material on a silicon wafer with H bonds on the surface includes: cleaning two quartz boats with anhydrous ethanol; evenly spreading sublimated sulfur powder in the first quartz boat; evenly mixing tungsten trioxide powder, erbium chloride powder and sodium chloride powder, and evenly spreading the mixed powder in the second quartz boat; taking out a silicon wafer with H bonds on the surface, using high-purity nitrogen to blow dry the surface of the silicon wafer, and placing the silicon wafer with H bonds on the surface with the polished surface facing down on the second quartz boat; placing the two quartz boats in a tube furnace for reaction, taking out the quartz boats from the tube furnace after the reaction is completed, and taking out the silicon wafer to obtain an erbium-phosphorus co-doped WS2 material sample.

5. The photodetector based on erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction according to claim 4, characterized in that: The reaction in the tube furnace includes: placing the first quartz boat in the low temperature zone of the tube furnace, placing the second quartz boat in the high temperature zone of the tube furnace, setting temperature control programs for the high temperature zone and the low temperature zone, and heating the tube furnace.

6. The photodetector based on erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction according to claim 5, characterized in that: The temperature control program of the high temperature zone includes: rising from room temperature to 970 degrees Celsius within the first 50 minutes, and keeping it at 970 degrees Celsius for 12 minutes, stopping heating and allowing the high temperature zone to cool naturally to room temperature; the temperature control program of the low temperature zone includes: keeping it at room temperature for 30 minutes, raising the temperature to 220 degrees Celsius in 20 minutes and keeping it for 12 minutes, stopping heating and allowing the low temperature zone to cool naturally to room temperature.

7. The photodetector based on erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction according to claim 6, characterized in that: When the reaction is carried out in the tubular furnace, 80 sccm of argon is introduced into the air inlet. When the high-temperature zone is heated to 875 degrees Celsius, the argon at the air inlet is replaced with an argon-hydrogen mixture with a flow rate of 60 sccm. After the reaction is completed and the tubular furnace is cooled to 500 degrees Celsius, the argon-hydrogen mixture is replaced with argon with a flow rate of 100 sccm.

8. The photodetector based on erbium-phosphorus co-doped WS2 / Si2H van der Waals heterojunction according to claim 1, characterized in that: When the reserved electrode pattern is plated, chromium and gold are used as counter electrodes with thicknesses of 5 nm and 50 nm respectively.

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