A photoelectric detector based on micro-nano wrinkled substrate and its preparation method

Abstract

The present invention belongs to the field of semiconductor technology and specifically discloses a photodetector based on a micro-nano corrugated substrate and a method for preparing the same. The method comprises the following steps: pre-treating a silicon wafer to obtain a silicon substrate; wherein the silicon wafer comprises a lower layer of single-crystal silicon and an upper layer of silicon oxide; depositing a magnesium metal layer by vacuum thermal evaporation on the silicon oxide of the silicon substrate; oxidizing the upper surface of the magnesium metal layer with ultraviolet ozone to form a corrugated micro-nano structure; dry-transferring molybdenum sulfide obtained by mechanical exfoliation onto the corrugated micro-nano structure on the upper surface of the magnesium metal layer; and depositing a source electrode and a drain electrode on the surface of the molybdenum sulfide using an electron beam evaporation coating system. The photodetector based on a micro-nano corrugated substrate provided by the present invention has the advantages of a simple preparation process, a fast response rate, good reliability, and high stability.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor technology, and in particular to a photoelectric detector based on a micro-nano wrinkled substrate and a preparation method thereof. Background Art

[0002] The performance optimization of photodetectors has long been limited by the dual constraints of the inherent properties of semiconductor materials and device structure design. In traditional planar devices, the light absorption efficiency of the semiconductor layer is significantly restricted due to the insufficient effective optical path length. At the same time, photogenerated carriers undergo multiple scattering and recombination processes in the extended migration path, resulting in an increase in the transport time of photogenerated carriers. These two factors together restrict the device response speed. Wrinkled micro-nanostructures can reduce carrier scattering and improve carrier mobility. For example, constructing photonic crystal structures on the substrate surface through lithography or nanoimprinting can enhance light absorption efficiency; using epitaxial strain engineering to induce semiconductor lattice distortion can optimize carrier transport characteristics. However, such methods rely on complex processes such as multi-step lithography and high-temperature annealing, which are costly and difficult to achieve uniform processing over large areas. In addition, traditional stress engineering mostly relies on external mechanical loading or heteroepitaxial growth, which can easily introduce interface defects and lead to uncontrollable structures.

[0003] Magnesium, a highly reactive metal, exhibits significant volume expansion and lattice mismatch during oxidation (lattice constant difference Δa = 0.101 nm), offering unique advantages for the self-organization of controllable micro- and nano-wrinkled structures. However, existing research has primarily focused on magnesium's anti-corrosion coatings or energy storage applications, while insufficiently exploring its potential for structural-functional integration in optoelectronics. In particular, the lack of coordinated regulation of magnesium's oxidation stress release mechanism makes it difficult to precisely match the wavelength, amplitude, and spatial distribution of the wrinkled structures to the optical and mechanical requirements of photodetectors. Summary of the Invention

[0004] In view of the above-mentioned shortcomings that currently exist, the present invention provides a photodetector based on a micro-nano corrugated substrate and a preparation method thereof. The present invention forms a corrugated structure by precisely controlling the thickness of the magnesium metal layer, the oxidizing atmosphere and the thermodynamic parameters, and utilizing the compressive stress during the magnesium oxidation process. This structure combines the photonic crystal effect with strain engineering properties to improve mobility. At the same time, the wavy morphology of the corrugated substrate can disperse external mechanical stress. Compared with traditional processes, the present invention abandons complex photolithography and external loading steps to achieve an integrated design of "material-structure-function", providing an innovative solution for the low-cost, large-scale manufacturing of high-performance photodetectors. The photodetector based on a micro-nano corrugated substrate of the present invention has the advantages of simple preparation process, fast response rate, good reliability and high stability.

[0005] In order to achieve the above object, the present invention provides a method for preparing a photodetector based on a micro-nano corrugated substrate, comprising the following steps:

[0006] S1. Pre-treating a silicon wafer to obtain a silicon substrate; wherein the silicon wafer comprises a lower layer of single crystal silicon and an upper layer of silicon oxide;

[0007] S2, depositing a magnesium metal layer on the silicon oxide of the silicon substrate by vacuum thermal evaporation, and oxidizing the upper surface of the magnesium metal layer by ultraviolet ozone to prepare a wrinkled micro-nanostructure;

[0008] S3. The molybdenum sulfide obtained by mechanical stripping is transferred and bonded to the wrinkled micro-nanostructure on the upper surface of the magnesium metal layer by a dry method, and a source electrode and a drain electrode are deposited on the surface of the molybdenum sulfide by an electron beam evaporation coating system.

[0009] According to one aspect of the present invention, in step S1, the pretreatment is: ultrasonically cleaning the silicon wafer with acetone, isopropyl alcohol and deionized water respectively, and then drying it by gradient heating.

[0010] According to one aspect of the present invention, the gradient temperature rise includes a first temperature, a second temperature, a third temperature and a fourth temperature; the first temperature is 40°C, and the holding time at the first temperature is 8-12 min; the second temperature is 55°C, and the holding time at the second temperature is 8~12 min; the third temperature is 80°C, and the holding time at the third temperature is 8~12 min; the fourth temperature is 110°C, and the holding time at the fourth temperature is 8~12 min.

[0011] It should be noted that gradient heating can avoid microcracks in the silicon oxide layer of the silicon wafer or interface delamination of the silicon wafer caused by sudden temperature changes. At the same time, since acetone, isopropyl alcohol and deionized water have different boiling points, we choose gradient heating to avoid leaving water marks on the surface of the silicon wafer during the drying process, which may cause unevenness.

[0012] According to one aspect of the present invention, in step S1, the single crystal silicon is p-heavily doped silicon.

[0013] It should be noted that p-heavily doped silicon serves as a conductive layer and silicon oxide serves as an insulating layer.

[0014] It should be noted that the silicon wafer in step S1 can be directly purchased.

[0015] Exemplarily, the silicon wafer in step S1 is a single-throw oxidized silicon wafer (P-type) produced by Suzhou Jingsi Electronic Technology Co., Ltd.

[0016] According to one aspect of the present invention, in step S2, the speed of the vacuum thermal evaporation deposition is 0.01-0.02 nm / s, and the vacuum degree of the vacuum thermal evaporation deposition is 1×10 -4 ~8×10 -5 Pa, the thickness of the magnesium metal layer is 3-5 nm.

[0017] According to one aspect of the present invention, in step S2, the temperature of the ultraviolet ozone oxidation is 30-60°C, the ozone concentration of the ultraviolet ozone oxidation is 50-100 ppm, the ozone flow rate of the ultraviolet ozone oxidation is 0.5-1.2 L / min, and the time of the ultraviolet ozone oxidation is 3-8 min.

[0018] Exemplarily, the above-mentioned ultraviolet ozone oxidation equipment is an ultraviolet ozone cleaning machine.

[0019] Exemplarily, the above-mentioned ultraviolet ozone oxidation equipment is an SC-UV-I type ultraviolet ozone cleaning machine.

[0020] According to one aspect of the present invention, in step S3, the source electrode and the drain electrode are both composed of two layers of materials, including a lower layer of chromium and an upper layer of gold.

[0021] According to one aspect of the present invention, the electron beam evaporation coating system includes an electron beam exposure system and a thermal evaporation system.

[0022] It should be noted that electron beam evaporation coating equipment consists of two parts (electron beam exposure system and thermal evaporation system).

[0023] According to one aspect of the present invention, the source electrode / drain electrode is first chromium-plated by an electron beam exposure system, and then gold is evaporated on the upper surface of the chromium by a thermal evaporation system.

[0024] Based on the same inventive concept, the present invention also provides a photoelectric detector based on a micro-nano wrinkled substrate, which is prepared by any of the above-mentioned preparation methods.

[0025] The present invention also provides the beneficial effects of the present invention:

[0026] (1) The present invention optimizes the band structure of molybdenum sulfide by creating a wrinkled substrate through stress mismatch induced by oxidation of magnesium metal. This reduces the energy of the bottom of the conduction band of molybdenum sulfide, increases the energy of the top of the valence band, reduces the band gap, and enhances the efficiency of carrier injection, thereby effectively improving carrier mobility. This solves the problem of low carrier concentration in metal oxide transistors and significantly improves transistor performance.

[0027] (2) The wrinkled surface (wrinkled micro-nanostructure) of the present invention acts as a photonic crystal. By scattering and resonating with localized states, the incident light is confined within the active layer, extending the equivalent optical path. The thickness of the molybdenum sulfide layer at the wrinkle trough is reduced, forming a quantum confinement effect, shortening the carrier migration path and reducing the transit time, thereby achieving the effect of improving the light response speed. This invention solves the problem of slow response speed of thin-film transistor photodetectors and significantly improves the performance of photodetectors. The present invention has a simple structure, low production cost, superior performance, and a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 Schematic diagram of a photoelectric detector based on a micro-nano wrinkled substrate according to the present invention;

[0029] Figure 2 These are atomic force microscope scans of the wrinkled micro-nanostructure of the photodetector according to Example 1 of the present invention; (a) is an atomic force microscope scan of the wrinkled micro-nanostructure on the upper surface of the magnesium metal layer according to Example 1; (b) is an atomic force microscope scan of the wrinkled micro-nanostructure after molybdenum sulfide has been transferred onto the wrinkled micro-nanostructure according to Example 1;

[0030] Figure 3 These are atomic force microscope scans of the photodetector of Comparative Example 1 of the present invention; wherein (a) is an atomic force microscope scan of the upper surface of the aluminum metal layer of Comparative Example 1; (b) is an atomic force microscope scan of the upper surface of the aluminum metal layer of Comparative Example 1 after molybdenum sulfide is transferred;

[0031] Figure 4 These are atomic force microscope scans of the photodetector of Comparative Example 2 of the present invention; wherein (a) is an atomic force microscope scan of the silicon oxide surface on the silicon wafer of Comparative Example 2; (b) is an atomic force microscope scan of the silicon oxide surface of Comparative Example 2 after molybdenum sulfide is transferred;

[0032] Figure 5 The present invention provides an atomic force microscope image of the wrinkled micro-nanostructure of the photodetector of Example 1, Comparative Example 1 or Comparative Example 2 of the present invention, and optical performance test and electrical performance test images after the device is prepared; wherein, (a) is an atomic force microscope image and amplitude of the wrinkled micro-nanostructure of the photodetector of Example 1; (b) is the transfer curve of the photodetector of Example 1 and Comparative Example 2 under a voltage of -60 V to 60 V; (c) is a graph showing the change of the transfer characteristic curve of the photodetector of Example 1 under conditions of irradiation with incident light of a wavelength of 457 nm and a source-drain voltage of 1 V; (d) is a graph showing the light response time of the photodetector of Example 1 under conditions of irradiation with incident light of a wavelength of 457 nm and a gate voltage of -60 V; and (e) is the response time of the rising and falling edges of the photocurrent of the photodetector of Example 1.

[0033] Description of reference numerals:

[0034] 1a, single crystal silicon; 1b, silicon oxide; 2, magnesium metal layer; 2a, metallic magnesium after volume expansion; 3, molybdenum sulfide; 4a, source electrode; 4b, drain electrode. DETAILED DESCRIPTION

[0035] To make the present invention easier to understand, the present invention is further described below with reference to specific examples. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Unless otherwise defined, the professional terms used below are consistent with the meanings understood by professional and technical personnel in this field; unless otherwise specified, the raw materials and reagents involved in this article can be purchased from the market or prepared by known methods.

[0036] It should be noted that the V ds 、V gs All of them are common knowledge in this field, namely, V ds is the drain-source voltage; V gs is the gate-source voltage.

[0037] In order to solve the problems of complex preparation process and low response rate of existing photodetectors, the inventors of this application provide a photodetector based on a micro-nano corrugated substrate, specifically Figure 1 As shown, a silicon wafer, a magnesium metal layer 2, a molybdenum sulfide 3, a source electrode 4a / a drain electrode 4b are stacked in sequence from bottom to top; wherein the silicon wafer includes a lower layer of single crystal silicon 1a and an upper layer of silicon oxide 1b; the magnesium metal layer 2 includes a magnesium metal substrate and a wrinkled micro-nanostructure (magnesium metal 2a after volume expansion) on the upper surface of the magnesium metal substrate; the single crystal silicon 1a serves as a gate; and the thickness of the magnesium metal layer 2 is 3-5 nm.

[0038] The inventors of the present application also provide a method for preparing a photodetector based on a micro-nano wrinkled substrate, comprising the following steps:

[0039] S1. Pre-treating a silicon wafer to obtain a silicon substrate; wherein the silicon wafer comprises a lower layer of single crystal silicon 1a and an upper layer of silicon oxide 1b;

[0040] S2, depositing a magnesium metal layer 2 on the silicon oxide 1b of the silicon substrate by vacuum thermal evaporation, and oxidizing the upper surface of the magnesium metal layer 2 by ultraviolet ozone to prepare a wrinkled micro-nanostructure (magnesium metal 2a after volume expansion);

[0041] S3: The molybdenum sulfide 3 obtained by mechanical stripping is transferred and bonded to the wrinkled micro-nanostructure (magnesium metal 2a after volume expansion) on the upper surface of the magnesium metal layer by a dry method, and the source electrode 4a and the drain electrode 4b are deposited on the surface of the molybdenum sulfide by electron beam evaporation.

[0042] Preferably, in step S1, the pretreatment is: ultrasonically cleaning the silicon wafer with acetone, isopropanol and deionized water respectively, and then drying it by gradient heating. The gradient heating includes a first temperature, a second temperature, a third temperature and a fourth temperature; the first temperature is 40 ° C, and the holding time of the first temperature is 8-12 min; the second temperature is 55 ° C, and the holding time of the second temperature is 8~12 min; the third temperature is 80 ° C, and the holding time of the third temperature is 8~12 min; the fourth temperature is 110 ° C, and the holding time of the fourth temperature is 8~12 min. In step S1, the single crystal silicon is p-heavily doped silicon. In step S2, the speed of the vacuum thermal evaporation deposition is 0.01~0.02 nm / s, and the vacuum degree of the vacuum thermal evaporation deposition is 1x10 -4 ~8x10 -5 Pa. In step S2, the temperature of the ultraviolet ozone oxidation is 30-60 ° C, the ozone concentration of the ultraviolet ozone oxidation is 50-100 ppm, the ozone flow rate of the ultraviolet ozone oxidation is 0.5-1.2 L / min, and the time of the ultraviolet ozone oxidation is 3-8 min. In step S3, the source electrode and the drain electrode are both composed of two layers of materials, including a lower layer of chromium and an upper layer of gold. The electron beam evaporation coating system includes an electron beam exposure system and a thermal evaporation system. The source electrode / drain electrode is first chromed by the electron beam exposure system, and then gold is evaporated on the upper surface of the chromium by the thermal evaporation system.

[0043] The following is further described with reference to specific embodiments and comparative examples.

[0044] Example 1

[0045] A method for preparing a photodetector based on a micro-nano wrinkled substrate comprises the following steps:

[0046] Step 1: Ultrasonic cleaning of a silicon wafer (the lower layer of heavily p-doped silicon and the upper layer of silicon oxide, purchased from Suzhou Jingsi Electronic Technology Co., Ltd.) was performed using acetone, isopropanol, and deionized water, respectively. Ultrasonic cleaning was performed in deionized water for 2 minutes. The wafer was then transferred to a vacuum drying oven and dried using a gradient heating process for 20 minutes to obtain a clean silicon substrate. The gradient heating process consisted of maintaining the wafers at 40°C, 55°C, 80°C, and 110°C for 10 minutes each.

[0047] Step 2: Deposit the silicon oxide insulating layer on the upper surface of the silicon substrate using a thermal resistance evaporation coating system (the temperature in the vacuum chamber is maintained at 25 °C and the pressure in the vacuum chamber is maintained at 1×10 -4 The magnesium metal layer was deposited at a deposition rate of 0.1 nm / s) and then transferred to an SC-UV-I ultraviolet ozone cleaning machine. Under the conditions of a UV lamp with a main wavelength of 185 nm and a secondary wavelength of 254 nm, oxygen was introduced with an oxygen flow rate of 0.8 L / min, the discharge power was adjusted to 45 W, the ozone concentration was controlled to 70 ppm, and the chamber temperature was set at 40 °C for oxidation for 6 min, obtaining a wrinkled micro-nanostructure on the upper surface of the magnesium metal layer.

[0048] Step 3: Use your fingers to gently press the tape with molybdenum sulfide crystals (Scotch tape, purchased from 3M) to attach the molybdenum sulfide to the prepared wrinkled micro-nanostructure and let it stand for 15 minutes. Use the source / drain electrode to first chromium-plated by an electron beam exposure system, and then evaporate gold on the upper surface of the chromium by a thermal evaporation system. The thickness of the lower chromium layer of the source / drain electrode is 10 nm, and the thickness of the upper gold layer of the source / drain electrode is 50 nm.

[0049] Comparative Example 1 (Replacing Mg with Metal Al)

[0050] A method for preparing a photodetector comprises the following steps:

[0051] Step 1: Ultrasonic cleaning of a silicon wafer (the lower layer of heavily p-doped silicon and the upper layer of silicon oxide, purchased from Suzhou Jingsi Electronic Technology Co., Ltd.) was performed using acetone, isopropanol, and deionized water, respectively. Ultrasonic cleaning was performed in deionized water for 2 minutes. The wafer was then transferred to a vacuum drying oven and dried using a gradient heating process for 20 minutes to obtain a clean silicon substrate. The gradient heating process consisted of maintaining the wafers at 40°C, 55°C, 80°C, and 110°C for 10 minutes each.

[0052] Step 2: Deposit the silicon oxide insulating layer on the upper surface of the silicon substrate using a thermal resistance evaporation coating system (the temperature in the vacuum chamber is maintained at 25 °C and the pressure in the vacuum chamber is maintained at 1×10 -4 Pa, deposition rate of 0.1 nm / s) and then transferred it to an SC-UV-I ultraviolet ozone cleaning machine. Under the conditions of ultraviolet lamp main wavelength of 185 nm and auxiliary wavelength of 254 nm, oxygen was introduced with an oxygen flow rate of 0.8 L / min, the discharge power was adjusted to 45 W, the ozone concentration was controlled to 70 ppm, and the chamber temperature was 40 ℃ for oxidation for 6 min to obtain an aluminum oxide layer on the upper surface of the aluminum metal layer.

[0053] Step 3: Use your fingers to gently press the tape with molybdenum sulfide crystals (Scotch tape, purchased from 3M) to attach the molybdenum sulfide to the prepared aluminum oxide layer. Let it stand for 15 minutes. Use the source / drain electrode to first chromium-plated by an electron beam exposure system, and then evaporate gold on the upper surface of the chromium by a thermal evaporation system. The thickness of the lower chromium layer of the source / drain electrode is 10 nm, and the thickness of the upper gold layer of the source / drain electrode is 50 nm.

[0054] Comparative Example 2 (No magnesium metal layer is deposited and no UV-ozone oxidation is performed)

[0055] A method for preparing a photodetector comprises the following steps:

[0056] Step 1: Ultrasonic cleaning of a silicon wafer (the lower layer of heavily p-doped silicon and the upper layer of silicon oxide, purchased from Suzhou Jingsi Electronic Technology Co., Ltd.) was performed using acetone, isopropanol, and deionized water, respectively. Ultrasonic cleaning was performed in deionized water for 2 minutes. The wafer was then transferred to a vacuum drying oven and dried using a gradient heating process for 20 minutes to obtain a clean silicon substrate. The gradient heating process consisted of maintaining the wafers at 40°C, 55°C, 80°C, and 110°C for 10 minutes each.

[0057] Step 2: Use your fingers to gently press the tape with molybdenum sulfide crystals (Scotch tape, purchased from 3M) to adhere the molybdenum sulfide to the silicon oxide insulating layer of the silicon wafer. Let it stand for 15 minutes. Use the source / drain electrodes to first chromium through an electron beam exposure system, and then evaporate gold on the upper surface of the chromium through a thermal evaporation system. The thickness of the lower chromium layer of the source / drain electrodes is 10 nm, and the thickness of the upper gold layer of the source / drain electrodes is 50 nm.

[0058] Performance testing and result analysis:

[0059] The photodetectors prepared in Example 1 and Comparative Examples 1-2 were analyzed by atomic force scanning electron microscopy. The results are as follows: Figures 2-4 As shown. Figure 2 (a) and Figure 2 (b) By comparison, it can be seen that the surface of the magnesium metal layer oxidized by ultraviolet ozone in Example 1 of the present invention forms obvious wrinkles, and after the molybdenum sulfide is transferred on the wrinkles, the molybdenum sulfide also has a relatively obvious wrinkle-type structure. Figure 3 (a) and Figure 3 (b) By comparison, it can be seen that the surface of the aluminum metal layer after UV ozone oxidation in Comparative Example 1 of the present invention has only slight wrinkles, and after the molybdenum sulfide is transferred on the wrinkles, the molybdenum sulfide also has only a slight wrinkle-type structure. Figure 4 (a) and Figure 4(b) By comparison, it can be seen that the silicon oxide on the silicon substrate has no wrinkles, and after the molybdenum sulfide is transferred to the silicon oxide, the molybdenum sulfide also has no obvious wrinkle structure. The photodetectors prepared in Example 1 and Comparative Examples 1-2 were tested for wrinkle amplitude, carrier mobility and light response time. The results are shown in Tables 1 and Figure 5 shown.

[0060] Table 1 Detection results of wrinkle amplitude, carrier mobility and photoresponse time of the photodetectors of Example 1 and Comparative Examples 1-2

[0061] ;

[0062] As can be seen from Table 1, the magnesium oxide wrinkled substrate on the magnesium metal layer of Example 1 of the present application significantly improves the carrier mobility and light response speed through its unique surface structure and magnesium layer design. However, due to the smooth substrate structure of Comparative Example 1 and Comparative Example 2 (aluminum oxide for Comparative Example 1 and silicon oxide for Comparative Example 2), the carrier mobility is low and the light response is slow due to severe interface scattering or insufficient light absorption. This result also shows the importance of material micro-nanostructure in device optimization. Figure 5 (a) It can be seen that the amplitude of the photodetector of Example 1 is 3-6 nm, showing periodic fluctuations, which indicates the high roughness and wrinkled interface characteristics of the upper surface of the magnesium metal layer. Figure 5 (b) It can be seen that the carrier mobility of the device based on the magnesium oxide wrinkled substrate of Example 1 is significantly higher than that of the device based on the silicon oxide substrate of Comparative Example 2. Figure 5 (c) It can be seen that under 457 nm light, the transfer curve of the photodetector of Example 1 shifts significantly and the current amplitude increases, indicating that the photogenerated carriers of the photodetector of Example 1 can be effectively separated and controlled. Figure 5 (d)- Figure 5 (e) Compared with Reference 1 (Ding S, Liu C, LiZ, et al. Ag-assisted dry exfoliation of large-scale and continuous 2Dmonolayers[J]. ACS nano, 2023, 18(1): 1195-1203.), it can be seen that the photocurrent rise time (7 ms) and fall time (22 ms) of the photodetector of Example 1 are much faster than those of the silicon oxide substrate device in Reference 1, and the response curve has high repeatability, indicating the reliability and stability of the photodetector of the present application under dynamic working conditions.

[0063] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a photodetector based on a micro-nano corrugated substrate, characterized in that: The following steps are involved: S1. Pre-treating a silicon wafer to obtain a silicon substrate; wherein the silicon wafer comprises a lower layer of single crystal silicon and an upper layer of silicon oxide; S2, depositing a magnesium metal layer on the silicon oxide of the silicon substrate by vacuum thermal evaporation, and oxidizing the upper surface of the magnesium metal layer by ultraviolet ozone to prepare a wrinkled micro-nanostructure; S3. The molybdenum sulfide obtained by mechanical stripping is transferred and bonded to the wrinkled micro-nanostructure on the upper surface of the magnesium metal layer by a dry method, and a source electrode and a drain electrode are deposited on the surface of the molybdenum sulfide by an electron beam evaporation coating system.

2. The method for preparing a photodetector based on a micro-nano wrinkled substrate according to claim 1, characterized in that: In step S1, the pretreatment is: ultrasonically cleaning the silicon wafer with acetone, isopropyl alcohol and deionized water respectively, and then drying it by gradient heating.

3. The method for preparing a photodetector based on a micro-nano wrinkled substrate according to claim 2, characterized in that: The gradient temperature rise includes a first temperature, a second temperature, a third temperature and a fourth temperature; the first temperature is 40°C, and the holding time at the first temperature is 8-12 min; the second temperature is 55°C, and the holding time at the second temperature is 8~12 min; the third temperature is 80°C, and the holding time at the third temperature is 8~12 min; the fourth temperature is 110°C, and the holding time at the fourth temperature is 8~12 min.

4. The method for preparing a photodetector based on a micro-nano wrinkled substrate according to claim 1, wherein: In step S1, the single crystal silicon is p-heavily doped silicon.

5. The method for preparing a photodetector based on a micro-nano wrinkled substrate according to claim 1, wherein: In step S2, the speed of the vacuum thermal evaporation deposition is 0.01-0.02 nm / s, and the vacuum degree of the vacuum thermal evaporation deposition is 1×10 -4 ~8×10 -5 Pa, the thickness of the magnesium metal layer is 3-5 nm.

6. The method for preparing a photodetector based on a micro-nano wrinkled substrate according to claim 1, characterized in that: In step S2, the temperature of the ultraviolet ozone oxidation is 30-60° C., the ozone concentration of the ultraviolet ozone oxidation is 50-100 ppm, the ozone flow rate of the ultraviolet ozone oxidation is 0.5-1.2 L / min, and the time of the ultraviolet ozone oxidation is 3-8 min.

7. The method for preparing a photodetector based on a micro-nano wrinkled substrate according to claim 1, characterized in that: In step S3, the source electrode and the drain electrode are both composed of two layers of materials, including a lower layer of chromium and an upper layer of gold.

8. The method for preparing a photodetector based on a micro-nano wrinkled substrate according to claim 7, characterized in that: The electron beam evaporation coating system includes an electron beam exposure system and a thermal evaporation system.

9. The method for preparing a photodetector based on a micro-nano wrinkled substrate according to claim 8, characterized in that: The source electrode / drain electrode is first chromium-plated by an electron beam exposure system, and then gold is evaporated on the upper surface of the chromium by a thermal evaporation system.

10. A photodetector based on a micro-nano corrugated substrate, characterized in that: The invention is prepared by the preparation method according to any one of claims 1 to 9.

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