Enhanced silicon-based photoelectric detector and preparation method thereof

Abstract

The invention discloses an enhanced silicon-based photoelectric detector and a preparation method thereof, and belongs to the technical field of semiconductor photoelectric detection.The enhanced silicon-based photoelectric detector comprises a bottom electrode film and a top electrode film and further comprises a silicon wafer with a heterojunction structure as a middle layer; the silicon wafer with the heterojunction structure sequentially comprises a silicon wafer with a nano column array structure, a molybdenum disulfide film, a nano magnetic bead layer and a silver nanowire layer from bottom to top. According to the enhanced silicon-based photoelectric detector, the enhanced silicon-based photoelectric detector is prepared through ion beam etching and a magnetron sputtering method, silicon-based interface reflection can be effectively reduced through a nanorod array structure, surface coating is conducted on a microstructure through two-dimensional molybdenum disulfide to form a heterojunction structure, the absorption efficiency of photons is improved, and the photoelectric detector can be applied to the field of photoelectric detection. And in combination with the nano magnetic bead layer on the surface, the detection efficiency is further improved by utilizing the coupling effect of the nano magnetic bead layer.

Description

Technical Field

[0001] The present invention belongs to the technical field of semiconductor photoelectric detection, and in particular relates to an enhanced silicon-based photoelectric detector and a preparation method thereof. Background Art

[0002] Photoelectric detection technology is the core of modern information technology and is of great significance to my country's national defense construction and economic development. At present, silicon-based photodetectors have excellent detection performance and have become the mainstream product in the market, but compared with other types of detectors, they still have some disadvantages. First, silicon-based detectors are limited by the band gap of silicon materials and can only detect up to 1100nm in the near infrared, with a limited detection range. Secondly, surface and bulk defects of silicon-based detectors will lead to higher dark current and noise, affecting their sensitivity and resolution. Furthermore, in the process of photoelectric detection, only part of the incident photons of planar silicon-based devices are absorbed, and the rest of the light is scattered or converted into heat energy, which seriously restricts the efficiency of the detector.

[0003] In recent years, in order to improve the sensitivity and detection efficiency of silicon-based photodetectors and expand their detection range, more research has focused on the construction of silicon-based materials and various heterojunction structures. Although their performance has been improved to a certain extent, the impact of interface defects and interface reflections on detection efficiency cannot be avoided. Therefore, in order to improve the efficiency of photoelectric detection, the existing technology needs to be further improved. Summary of the invention

[0004] In view of the above technical problems, the present invention proposes an enhanced silicon-based photodetector and a preparation method thereof.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] One of the technical solutions of the present invention:

[0007] An enhanced silicon-based photodetector, comprising: a bottom electrode film and a top electrode film, and also comprising a silicon wafer with a heterojunction structure;

[0008] The silicon wafer with a heterojunction structure comprises, from bottom to top, a silicon wafer with a nano-column array structure, a molybdenum disulfide film, a nano-magnetic bead layer and a silver nano-wire layer.

[0009] Optionally, the diameter of the nanocolumns in the nanocolumn array is 200nm-500nm, and the spacing is 200nm-500nm.

[0010] Optionally, the nanomagnetic beads are ferroferric oxide, and the particle size thereof is 100nm to 300nm.

[0011] Optionally, the diameter of the silver in the silver nanowire layer is 20 nm.

[0012] Optionally, the electrode structures of the bottom electrode film and the top electrode film are: Si heterojunction (silicon wafer with heterojunction structure) / Ti (20-25nm) / Cu (280nm-300nm) / Ti (10nm-15nm).

[0013] Optionally, the thickness of the molybdenum disulfide film is 1 to 5 molecular layers. The basic structural unit of molybdenum disulfide is a three-atomic layer consisting of a layer of molybdenum atoms sandwiched between two layers of sulfur atoms, and this structure is called a "molecular layer". Therefore, "1-5 molecular layers" of molybdenum disulfide refers to 1-5 such three-atomic layers stacked together.

[0014] The second technical solution of the present invention:

[0015] A method for preparing an enhanced silicon-based photodetector comprises the following steps:

[0016] The nanorod array structure was prepared on the surface of the silicon wafer by ion beam etching to obtain sample 1;

[0017] A layer of molybdenum disulfide film is coated on the surface of the sample 1 by combining magnetron sputtering and high vacuum chemical vapor vulcanization to obtain sample 2;

[0018] Spraying an alcohol solution containing nano-magnetic beads onto the surface of the sample 2 and drying the sample to obtain a sample 3;

[0019] Spin-coating a silver nanowire solution on the surface of the sample 3 to obtain a silicon wafer with a heterojunction structure;

[0020] A top electrode film and a bottom electrode film are formed on the upper and lower surfaces of the silicon wafer with the heterojunction structure to prepare the enhanced silicon-based photodetector.

[0021] Optionally, the ion beam etching method comprises the following steps:

[0022] The silicon wafer is cleaned, coated, exposed, developed and etched in sequence;

[0023] In the etching process, the silicon wafer needs to be placed on a rotating sample holder.

[0024] Furthermore, the conditions in the etching process are: at 2.0×10 -4 Etching was performed in MP mode under Pa conditions, where the MP mode was microwave plasma for fine etching of materials. The specific condition parameters of the process were: 12sccm of Ar was continuously introduced into the etching chamber, and under the action of a 350W RF power supply, high-density Ar was generated by discharging through a vacuum cathode tube. + Plasma was used to perform five cycles of etching for 30 seconds and stopping for 60 seconds to complete the etching of the target object.

[0025] Optionally, the magnetron sputtering method comprises the following steps:

[0026] The etched silicon wafer is subjected to a process combining metal molybdenum magnetron sputtering with high vacuum chemical vapor sulfurization.

[0027] Furthermore, during the magnetron sputtering of the metal molybdenum, the silicon wafer needs to be placed on a rotating sample holder;

[0028] The parameters of the molybdenum magnetron sputtering process are as follows: using high purity Mo with a purity of 99.99% as the target material; the vacuum is less than 2.0×10 -5 Pa, the sputtering gas Ar flow rate is 20 sccm, the sputtering gas pressure is 1.0 Pa, the sputtering power is 15 W, and the metal Mo film deposition time is 5-80 s.

[0029] Furthermore, the conditions in the high vacuum chemical vapor vulcanization process are: the vulcanization reaction sources are sodium chloride and sublimated sulfur, and the mass ratio of the two is 1.5:4; the vulcanization temperature is 700-900° C.; and the reaction time is 30 minutes.

[0030] Optionally, the concentration of the alcohol solution of the nanomagnetic beads is 0.1 g / 10 mL.

[0031] Optionally, the conditions during the drying process are:

[0032] Bake at 100℃ for 3min.

[0033] Optionally, the concentration of the silver nanowire solution is 4 mg / mL.

[0034] Compared with the prior art, the present invention has the following advantages and technical effects:

[0035] The present invention provides an enhanced silicon-based photodetector, in which a nanocolumn microstructure can effectively reduce silicon-based interface reflection, and the microstructure is surface-coated with a two-dimensional material, molybdenum disulfide, to form a heterojunction structure, thereby improving the absorption efficiency of photons, and then combined with nanomagnetic beads prepared on the surface, the coupling effect is utilized to further improve its detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0037] Figure 1 The sample holder used in the ion beam etching and sputtering process in Example 1 of the present invention;

[0038] Figure 2 This is an electron microscope photograph of sample 2 in Example 1 of the present invention;

[0039] Figure 3 is the Raman spectrum of sample 2 in Example 1 of the present invention;

[0040] Figure 4 The magnetic bead sprayer used in the preparation process of Example 1 of the present invention;

[0041] Figure 5 This is an electron microscope photograph of sample 3 in Example 1 of the present invention;

[0042] Figure 6 This is the ultraviolet diffuse reflectance spectrum of the photoelectric detectors prepared in Example 1 and Comparative Examples 1-3 for light waves in the range of 200nm to 900nm. DETAILED DESCRIPTION

[0043] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0044] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0045] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0046] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0047] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0048] An embodiment of the present invention provides a method for preparing an enhanced silicon-based photodetector, comprising the following steps:

[0049] (1) Using the template method and ion beam etching, a uniform nanopillar array structure is prepared on the surface of the silicon wafer, which effectively reduces the scattering effect of the substrate on light waves and increases the absorption of light. In order to make the bottom structure of the nanopillars more flat and complete, the wafer (circular silicon wafer substrate, the same below) is placed on the sample holder during ion beam etching. The sample holder is centered on the main axis and rotates around the axis in a gyroscopic manner at a side angle of 10° to 15° while etching.

[0050] (2) A magnetron sputtering method is used to sputter a metal molybdenum seed layer on the surface of a wafer having a silicon nanocolumn microstructure, and then a high vacuum chemical vapor sulfurization annealing method is used to sulfurize the metal molybdenum film into a molybdenum disulfide film. In order to make the molybdenum disulfide film completely and evenly coated on the surface of the nano-microstructure, a sample holder is also used in the magnetron sputtering process. The wafer having the microstructure is placed on the sample holder, and the metal Mo film is sputtered during the rotation process to ensure the uniformity of the metal Mo film after sulfurization.

[0051] (3) In order to increase the light absorption efficiency of the heterojunction structure, Fe3O4 nanomagnetic beads with a particle size of 100nm to 300nm are used as sensitizing materials and are dispersed around the columnar structure in the sample prepared in step (2). The micromagnetic field of the Fe3O4 nanomagnetic beads is coupled to the electromagnetic wave to effectively improve the light absorption efficiency of the heterojunction structure. Among them, the distribution of the Fe3O4 nanomagnetic beads on the surface of the nano-microstructure has a significant effect on light absorption. In order to make the Fe3O4 nanomagnetic beads more evenly distributed on the surface of the heterojunction structure, the present invention adopts the following method: Figure 4 The magnetic bead sprayer shown is used to disperse the nano-magnetic beads in anhydrous ethanol solution before spin coating. The sprayer is inverted and the mixing and stirring mode is turned on. It is then turned over and 1.0 Pa of inert gas is introduced to spray out the nano-magnetic bead dispersion. The nano-magnetic beads are then evenly dispersed on the surface of the nano-microstructure by spin coating with a coater to obtain a silicon wafer with a heterojunction structure.

[0052] (4) A top electrode film and a bottom electrode film are formed on the upper and lower surfaces of a silicon wafer having a heterojunction structure to prepare the enhanced silicon-based photodetector.

[0053] The raw materials used in the present invention are all purchased from the market.

[0054] The technical solution of the present invention is further illustrated by the following embodiments.

[0055] Example 1

[0056] A method for preparing an enhanced silicon-based photodetector comprises the following steps:

[0057] 1. Preparation of Silicon-based Surface Nanostructures

[0058] (1) Substrate cleaning: Use acetone, anhydrous ethanol, and deionized water at 40 kHz to clean an area of ​​20.25 cm 2 The silicon wafer substrate (silicon wafer, the same below) was ultrasonically cleaned for 15 minutes, dried with N2, baked on a hot plate at 120°C for 3 minutes, and then cooled;

[0059] (2) Glue coating on silicon wafer surface: Place the cleaned silicon wafer in the center of the coating machine tray, add 20 mL of 5214 photoresist in the center of the silicon wafer, set the speed to 2000 rpm for 3 seconds, accelerate to 5000 rpm for 5 seconds, and maintain it at 5000 rpm for 10 seconds, then reduce the speed to 0 rpm for 2 seconds; and bake it on a hot plate at 100 °C for 90 seconds;

[0060] (3) Exposure: Using a circular array structure with a diameter of 500 nm and a pitch of 500 nm as a mask, the coated wafer is exposed using an exposure machine in a non-contact mode at 15 mW for 4.5 s.

[0061] (4) Development: The exposed silicon wafer was placed in developer NMD-3 and developed in a shaking manner for 190 seconds, then rinsed with running deionized water and quickly dried with N2;

[0062] (5) Etching: The exposed and developed silicon wafer is placed on the sample holder in the vacuum chamber of the ion etcher. -4 Under the conditions of Pa, in MP mode (12sccm of Ar is continuously introduced into the etching chamber, and high-density Ar is generated by discharge through the vacuum cathode tube under the action of 350W RF power). + Plasma, 5 cycles of etching for 30s and stopping for 60s are performed to complete the etching of the target object), that is, 5 cycles of etching for 30s and stopping for 60s are performed at a radio frequency medium power of 400W to obtain sample 1;

[0063] (6) Degumming: The etched sample 1 was placed in NMP degumming solution and ultrasonically degummed at a power of 40 W for 2 min.

[0064] During this process, the sample holder rotates in a gyroscopic torsion pendulum (the speed is 30 rpm) to ensure the verticality and flatness of the channel at the bottom of the silicon nanopillar microstructure;

[0065] 2. Silicon-based nanostructures coated with two-dimensional MoS2 thin films

[0066] (1) A silicon wafer with a silicon nanorod microstructure on the surface was used as a substrate, which was cleaned in acetone, anhydrous ethanol and deionized water for 15 min in sequence, and then dried with dry nitrogen;

[0067] (2) The cleaned substrate is placed in a vacuum chamber of magnetron sputtering, and a high-purity Mo with a purity of 99.99% is used as the target material. The vacuum degree is less than 2.0×10 -5 Pa, the sputtering gas Ar flow rate is 20sccm, the sputtering gas pressure is 1.0Pa, the sputtering power is 15W, and the metal Mo film deposition time is 20s; during the sputtering process, the sample holder rotates in a gyro-shaped torsion pendulum (the speed is 30rmp / min) to ensure the uniformity of the deposition of the metal Mo film on the surface and bottom of the silicon nanostructure;

[0068] (3) The metal Mo film is sulfurized using a single temperature zone tube furnace. The microstructure with the metal Mo film deposited is placed in a vacuum chamber of the vacuum tube furnace and evacuated to 2.0×10 -4 Pa, the annealing furnace was placed in a non-sample position and heated at a rate of 2.8°C / min to the reaction temperature (700°C), the annealing furnace was moved to the sample position, the reaction time was 30 min, and then the annealing furnace was moved to a non-sample position, and sample 2 was obtained after rapid cooling;

[0069] The wafer surface of the sample with the metal Mo film deposited was facing away from the airflow direction. During the heating process, the carrier gas flow rate was (80 sccmAr, 20 sccm H2), and during the reaction process, the carrier gas flow rate was reduced (20 sccmAr, 5 sccm H2). During the reaction, the sample was 20 cm away from the catalytic reaction source, and they were located at the two ends of the annealing furnace temperature zone respectively. The catalytic reaction source was 1.5 g of sodium chloride and 4.0 g of sublimated sulfur. During the reaction, the angle valve between the vacuum chamber and the pump was in a closed state.

[0070] 3. Evenly disperse nanomagnetic beads on the surface of heterojunction structure

[0071] (1) Disperse 0.1 g of 100 nm ferroferric oxide nanoparticles in 10 mL of anhydrous ethanol solution and mix well;

[0072] (2) The anhydrous ethanol solution containing the nano-magnetic beads is placed in a sprayer, such as Figure 4 As shown, nitrogen is connected to the upper end of the sprayer, wherein the nitrogen input pressure is 1.0Pa;

[0073] (3) The wafer with MoS2 coated silicon nanostructures is placed at the center of the chuck of the coating machine and adsorbed. After the coating machine is started, the speed increases from 0 rpm to 2000 rpm in 3 s;

[0074] (4) After the rotation speed (2000 rpm) is stabilized, the sprayer is turned on to spray the solution onto the surface of the wafer with the silicon nanostructure coated with MoS2 for spin coating for 5 seconds;

[0075] (5) After the spin coating is completed, the wafer coated with nano-magnetic beads is placed on a heating plate and baked at 100° C. for 3 min to prepare sample 3;

[0076] 4. Preparation of enhanced silicon-based photodetectors

[0077] (1) a silver nanowire solution with a diameter of 20 nm and a concentration of 4 mg / mL was spin-coated at a speed of 1500 rpm for 40 s using a coating machine to form a mesh structure on the surface of the wafer with a microstructure so as to form a bridge structure between the nanopillars, thereby obtaining sample 4;

[0078] (2) Electron beam evaporation was used to prepare a bottom electrode film and a top electrode film on a Si / SiO2 substrate with an area of ​​0.5 cm×0.5 cm. The sacrificial SiO2 layer was then etched by 5% HF to separate the bottom electrode film and the top electrode film from the substrate and transfer them to the edge of the surface of the wafer sample 4 with the heterojunction.

[0079] The specific preparation parameters are: background vacuum degree 1.0×10 -4 Pa, the electrode structure is Ti (20nm) / Cu (280nmnm) / Ti (10nmnm), the metal Ti evaporation power is 110kW, the rate is 0.1nm / s; the metal Cu evaporation power is 95kW, the rate is 0.5nm / s.

[0080] Figure 1 The sample holder used in the ion beam etching and sputtering process in Example 1 of the present invention; in order to make the bottom structure of the nanocolumn more flat and complete, the wafer is placed as follows during ion beam etching Figure 1 On the sample holder shown in FIG. 1 , the sample holder is centered on the main axis and rotates 10° to 15° around the axis in a gyroscopic manner to perform etching. In addition, in order to make the molybdenum disulfide film completely and evenly coated on the surface of the silicon nanostructure, the magnetron sputtering process is also used as follows Figure 1 The sample holder shown has a wafer with a microstructure placed on it, and a metal Mo film is sputtered during the rotation process to ensure the uniformity of the metal Mo film after sulfurization.

[0081] Figure 2 is an electron microscope photograph of sample 2 in Example 1 of the present invention; Figure 2 It can be seen that the surface of the silicon nanorods has been completely covered by the molybdenum disulfide film.

[0082] Figure 3 This is the Raman spectrum of sample 2 in Example 1 of the present invention; it can be seen from the figure that only molybdenum disulfide has obvious A 1g and E 2g 1 Characteristic peak, the wave number difference is 22.8cm -1, proving that the thickness of the molybdenum disulfide film coated on the surface of the silicon nanorods is approximately 3 molecular layers.

[0083] Figure 4 It is the sprayer used in the preparation process of Example 1 of the present invention; before spin coating, the nano magnetic beads are dispersed in anhydrous ethanol solution, and the mixing and stirring device is turned upside down, then turned over and 1.0Pa inert gas is introduced to spray out the nano magnetic bead dispersion, and the nano magnetic beads are evenly dispersed on the surface of the nano microstructure by spin coating with a coater.

[0084] Figure 5 This is an electron microscope photograph of sample 3 in Example 1 of the present invention. It can be seen from the figure that the nanomagnetic beads are evenly dispersed on the surface of the nano-microstructure.

[0085] The difference between Example 2-12 and Example 1 is that the "metal Mo film deposition time" and "reaction temperature" in step 2 (2) and (3) are different. The specific parameters in the preparation process of Example 1-12 are shown in Table 1:

[0086] Table 1

[0087]

[0088] Comparative Example 1

[0089] A method for preparing a photoelectric detector is different from that of Example 1 in that steps 2 and 3 are not included, and a photoelectric detector having only a silicon nanorod structure is prepared.

[0090] Comparative Example 2

[0091] A method for preparing a photoelectric detector, which is different from Example 1 in that step 3 is not included, and a photoelectric detector having only silicon nanorods + molybdenum disulfide is prepared.

[0092] Comparative Example 3

[0093] A method for preparing a photoelectric detector, which is different from Example 1 in that steps 1 and 2 are not included, and a photoelectric detector having only a silicon+nanosphere structure is prepared.

[0094] The photodetectors prepared in the above comparative examples 1-3 all include a silver nanowire layer.

[0095] Effect verification

[0096] The reflectance of the photoelectric detectors prepared in Example 1 and Comparative Examples 1-3 is tested as a function of wavelength.

[0097] Figure 6The ultraviolet diffuse reflectance spectra of the photodetectors prepared in Example 1 and Comparative Examples 1-3 for the light wave range of 200nm to 900nm are shown, among which the curve of silicon nanopillar + molybdenum disulfide + nanosphere (100nm) corresponds to Example 1, the curve of silicon nanopillar corresponds to Comparative Example 1, the curve of silicon nanopillar + molybdenum disulfide corresponds to Comparative Example 2; the curve of silicon + nanosphere (100nm) corresponds to Comparative Example 3; it can be seen from the figure that when the plane silicon surface is spin-coated with magnetic beads with a particle size of 100nm (Comparative Example 3), its reflectivity is the highest, followed by the nanopillar microstructure prepared only on the silicon surface (Comparative Example 1), and its reflectivity is reduced again when the molybdenum disulfide film is uniformly coated on the silicon pillar surface. The one with the lowest reflectivity is the one in which the surface of the silicon nanostructure is coated with molybdenum disulfide and then spin-coated with Fe4O3 nanomagnetic beads. The coupling effect of Fe4O3 nanomagnetic beads on light significantly reduces the reflection of the material to light and increases its light absorption efficiency.

[0098] The above are only preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An enhanced silicon-based photodetector, comprising a bottom electrode film and a top electrode film, characterized in that: Also included is a silicon wafer having a heterojunction structure; The silicon wafer with a heterojunction structure comprises, from bottom to top, a silicon wafer with a nano-column array structure, a molybdenum disulfide film, a nano-magnetic bead layer and a silver nano-wire layer.

2. The enhanced silicon-based photodetector according to claim 1, characterized in that: The diameter of the nano-columns in the nano-column array structure is 200nm-500nm, and the spacing is 200nm-500nm.

3. The enhanced silicon-based photodetector according to claim 1, characterized in that: The thickness of the molybdenum disulfide film is less than 5 molecular layers.

4. The enhanced silicon-based photodetector according to claim 1, characterized in that: The nano magnetic beads are ferroferric oxide, and the particle size thereof is 100nm to 300nm.

5. The enhanced silicon-based photodetector according to claim 1, characterized in that: The diameter of silver in the silver nanowire layer is 20 nm.

6. A method for preparing an enhanced silicon-based photodetector, characterized in that: The following steps are involved: The nanorod array structure was prepared on the surface of the silicon wafer by ion beam etching to obtain sample 1; A layer of molybdenum disulfide film is coated on the surface of the sample 1 by combining magnetron sputtering with high vacuum chemical vapor vulcanization to obtain sample 2; Spraying an alcohol solution containing nano-magnetic beads onto the surface of the sample 2 and drying the sample to obtain a sample 3; Spin-coating a silver nanowire solution on the surface of the sample 3 to obtain a silicon wafer with a heterojunction structure; A top electrode film and a bottom electrode film are formed on the upper and lower surfaces of the silicon wafer having a heterojunction structure to prepare the enhanced silicon-based photodetector according to any one of claims 1 to 5.

7. The method for preparing an enhanced silicon-based photodetector according to claim 6, characterized in that: The ion beam etching method comprises the following steps: The silicon wafer is cleaned, coated, exposed, developed and etched in sequence; Wherein, the conditions during the etching process are: At 2.0×10 -4 Under Pa conditions, five cycles were performed with etching for 30 s and rest for 60 s.

8. The method for preparing an enhanced silicon-based photodetector according to claim 6, characterized in that: The magnetron sputtering method comprises the following steps: sputtering and sulfurizing the silicon wafer with metal molybdenum; The parameters of the molybdenum sputtering process are as follows: Mo is used as the target material; the vacuum degree is less than 2.0×10 -5 Pa, the sputtering gas Ar flow rate is 20 sccm, the sputtering gas pressure is 1.0 Pa, the sputtering power is 15 W, and the metal Mo film deposition time is 5-80 s; and / or The conditions in the vulcanization process are as follows: the vulcanization reaction sources are sodium chloride and sublimed sulfur, the mass ratio of the two is 1.5:4; the vulcanization temperature is 700-900° C.; and the reaction time is 30 minutes.

9. The method for preparing an enhanced silicon-based photodetector according to claim 7 or 8, characterized in that: During the etching and the metal molybdenum sputtering processes, the silicon wafer needs to be placed on a rotating sample holder.

10. The method for preparing an enhanced silicon-based photodetector according to claim 6, characterized in that: The concentration of the alcohol solution containing nanomagnetic beads is 0.01 g / mL; and / or The concentration of the silver nanowire solution is 4 mg / mL.

Images