0D / 2D homojunction photoelectric sensor based on MoS2 and preparation method thereof
By integrating MoS2 quantum dots with single-layer MoS2 in a 0D/2D heterojunction structure, the MoS2-based photodetector overcomes the low light absorption issue, achieving high response rates and detection capabilities, enhancing its suitability for intelligent transportation systems and reducing reliance on foreign semiconductor chips.
Patent Information
- Application Number
- CN202411761357.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-03
- Publication Date
- 2025-03-18
AI Technical Summary
Current TPMS systems in China rely heavily on imported semiconductor chips from companies like Infineon and General Electric, limiting domestic competition and increasing costs, while MoS2-based sensors face challenges due to low light absorption capacity, hindering their application in intelligent transportation systems.
A 0D/2D heterojunction photodetector is developed by integrating MoS2 quantum dots with single-layer MoS2, enhancing light absorption and detection performance through a specific fabrication method involving mechanical exfoliation, chemical synthesis, and thermal treatment.
The resulting MoS2-based 0D/2D heterojunction photodetector achieves a response rate of up to 27.6 A/W and a detection rate of 2.13×10^11 Jones at 532nm, significantly improving the sensor's light absorption and application potential in automotive safety monitoring.
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Figure CN119653900A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of optoelectronic devices, and in particular to a 0D / 2D homojunction photoelectric sensor based on MoS2 and a preparation method thereof. Background Art
[0002] Photoelectric sensors can convert optical signals into electrical signals and are widely used in the fields of industry, military, and medicine. In recent years, in response to the requirements of the strategic development plan of the Internet of Things, efficient and safe intelligent traffic management systems have become a key development area in my country. Against this background, the intelligent tire pressure monitoring system (TPMS) came into being. The emergence of TPMS has greatly reduced the risk of tire accidents such as tire blowouts and protected the lives of passengers, so it has received widespread attention and adoption. However, the current TPMS market in my country is mostly monopolized by foreign products. Although there are some TPMS product suppliers in my country, the core TPMS sensor chips are all purchased from foreign semiconductor companies such as Infineon, General Electric (NovaSensor) and Schrader. Not only are the core technologies controlled by others, but the prices are also high, which is not conducive to the promotion and application of TPMS and market competition. Therefore, it is urgent to develop efficient, sensitive and low-cost sensors.
[0003] Among them, MoS2 has attracted extensive attention due to its optoelectronic properties such as high carrier mobility and adjustable band gap, and is considered to be one of the important candidates for high-performance photoelectric sensors. However, the atomic-level thickness (0.65nm) of a single layer of MoS2 results in its weak light absorption ability, which hinders its practical application. Therefore, improving the light absorption ability of MoS2 is a key technology to promote the practical application of MoS2 devices. Summary of the invention
[0004] In view of some deficiencies in the prior art, the present invention provides a photoelectric sensor based on a 0D / 2D homojunction of MoS2 and a preparation method thereof. The present invention provides a photoelectric sensor based on a 0D / 2D homojunction of MoS2 and integrates MoS2 quantum dots with high-efficiency light absorption with a single layer of MoS2 by using a synergistic effect to improve the detection performance of the photoelectric sensor. The photoelectric sensor based on a 0D / 2D homojunction of MoS2 of the present invention has a maximum responsivity of 27.6A / W and a maximum detection rate of 2.13×10 11 Jone.
[0005] A method for preparing a 0D / 2D homojunction photoelectric sensor based on MoS2, characterized in that it comprises the following steps:
[0006] Step 1: preparing a patterned silicon wafer electrode;
[0007] Step 2: Prepare a single-layer MoS2 film by mechanical exfoliation, and transfer the obtained single-layer MoS2 film to the processed patterned silicon wafer electrode by dry method;
[0008] Step 3: Prepare sodium molybdate solution: dissolve sodium molybdate in deionized water, dissolve by ultrasonication, and then add hydrochloric acid to adjust the pH value of the sodium molybdate solution to 6-6.5;
[0009] Prepare L-cysteine solution: dissolve L-cysteine in deionized water and dissolve by ultrasonication;
[0010] Step 4: Mix the sodium molybdate solution and the L-cysteine solution, then transfer to a polytetrafluoroethylene reactor, and react at 180-200° C. for 36-38 hours; after cooling to room temperature, centrifuge at a speed of 11000-12000 r / min for 30-40 minutes to obtain a MoS2 quantum dot supernatant;
[0011] Step 5: Spin-coat the MoS2 quantum dot supernatant onto the monolayer MoS2 film on the patterned silicon wafer electrode, dry at 70-80°C for 10-13 min, pass nitrogen gas and anneal at 200-220°C for 20-30 min to obtain a MoS2-based 0D / 2D homojunction photoelectric sensor.
[0012] Furthermore, in step 1, the substrate is a patterned silicon wafer electrode, and the steps of preparing the electrode include:
[0013] Step 1.1 Take a 1cm×1cm×1.5mm silicon wafer with an oxide layer thickness of 300nm;
[0014] Step 1.2: ultrasonically clean the silicon wafer using acetone, anhydrous ethanol and deionized water in sequence to remove oil and impurities on the surface of the silicon wafer. The ultrasonic cleaning time for each cleaning is 5 to 8 minutes.
[0015] Step 1.3 Use nitrogen to blow off the water droplets on the electrode;
[0016] Step 1.4 Drying in a drying oven at 60-80°C to improve the adhesion of the photoresist;
[0017] Step 1.5: Take AZ5214 positive photoresist and drop it on the center of the silicon wafer. Spin it at 500 r / min for 5-10 s, and then spin it at 2000 r / min for 60-65 s.
[0018] Step 1.6: Place the silicon wafer on a heating table and dry it at 120-150°C for 1-2 minutes to solidify the solvent in the photoresist;
[0019] Step 1.7: Place the silicon wafer on the workbench of the electron beam lithography machine and fix it;
[0020] Step 1.8 Import the electrode pattern drawn by I-edit software into the photolithography machine and start the photolithography machine for photolithography;
[0021] Step 1.9: Place the photoresist / silicon wafer after photolithography in a developer and take it out after developing for 1 to 2 minutes;
[0022] Step 1.10: Use deionized water to clean and remove the residual developer in the graphic area;
[0023] Step 1.11: Place the exposed silicon wafer in a buffered hydrofluoric acid solution and etch for 20 to 25 seconds;
[0024] Step 1.12: Rinse the silicon wafer 5 to 6 times with deionized water to remove the etching solution;
[0025] Step 1.13 depositing titanium and gold films on the silicon wafer by electron beam evaporation;
[0026] Step 1.14: Use AZ degumming solution to clean the coated silicon wafer, remove the photoresist-gold film composite structure, and obtain a patterned silicon wafer electrode.
[0027] Furthermore, in step 2, the patterned silicon wafer electrode is subjected to the following treatment before transferring the single-layer MoS2 film:
[0028] Step 2.1: ultrasonically clean the substrate using acetone, anhydrous ethanol and deionized water in sequence to remove oil and impurities on the surface of the silicon wafer, with each ultrasonic cleaning lasting 5 to 8 minutes;
[0029] Step 2.2 Blow off the water droplets on the substrate with nitrogen;
[0030] Step 2.3 Drying in a drying oven at 60-80°C;
[0031] Step 2.4: Plasma or ozone cleaning for 10 to 20 minutes to increase the hydrophilicity of the substrate surface.
[0032] Furthermore, in step 1, the heating temperature of the dry transfer is 70-80° C., and the heating time is 1-2 min.
[0033] Furthermore, in step 2, the amounts of sodium molybdate and deionized water in the sodium molybdate solution are 0.25 g and 25 mL respectively, and the solution is ultrasonicated for 5 to 8 min; and the molar concentration of hydrochloric acid is 0.1 mol / L.
[0034] Furthermore, in step 2, the amounts of L-cysteine and deionized water in the L-cysteine solution are 0.5 g and 50 mL, respectively, and the solution is sonicated for 10 to 12 minutes.
[0035] Furthermore, the spin coating in step 4 is to take 100-200 μL of the supernatant of MoS2 quantum dots and drop it onto the single-layer MoS2 film with a substrate, and spin coat it at a speed of 2000-3000 r / min for 20-30s.
[0036] The 0D / 2D homojunction photoelectric sensor based on MoS2 made by the above preparation method is characterized in that it includes a substrate, an electrode, a single-layer MoS2 thin film layer and a MoS2 quantum dot layer, and the single-layer MoS2 thin film layer and the MoS2 quantum dot layer are stacked in sequence in the channel structure formed by the electrode.
[0037] The beneficial effects of the present invention are:
[0038] The present invention integrates MoS2 quantum dots with high-efficiency light absorption with a single layer of MoS2 to prepare a MoS2-based 0D / 2D homojunction photoelectric sensor. In this structure, MoS2 is used as a high-mobility carrier transmission channel, while the MoS2 quantum dots act as an effective light absorber to enhance the local electric field around MoS2. The MoS2-based 0D / 2D homojunction photoelectric sensor prepared by the method of the present invention has a maximum response rate of 27.6A / W and a maximum detection rate of 2.13×10 11 Jone.
[0039] The present invention utilizes the synergistic effect of MoS2 quantum dots and monolayer MoS2 to accelerate the separation rate of photogenerated carriers in the homojunction and improve the light absorption capacity of MoS2, making it have great application potential in automobile safety monitoring. BRIEF DESCRIPTION OF THE DRAWINGS
[0040] Figure 1 (a) TEM image and (b) particle size distribution statistics of MoS2 quantum dots;
[0041] Figure 2 (a) Optical microscope image and (b) schematic diagram of the structure of MoS2-based 0D / 2D homojunction photoelectric sensor;
[0042] Figure 3 (a) Photoresponse diagram and (b) photocurrent rise and fall time diagram of MoS2-based 0D / 2D homojunction photosensor;
[0043] Figure 4 (a) Responsivity and (b) detectivity of MoS2-based 0D / 2D homojunction photoelectric sensors in different bands.
[0044] Figure 5 It is the energy band diagram of MoS2-based 0D / 2D homojunction photoelectric sensor. DETAILED DESCRIPTION
[0045] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.
[0046] Embodiment 1:
[0047] (1) Preparation of patterned electrodes
[0048] Take a 1cm×1cm×1.5mm silicon wafer with an oxide layer thickness of 300nm; use acetone, anhydrous ethanol and deionized water to ultrasonically clean the silicon wafer in turn to remove oil and impurities on the surface of the silicon wafer, and the ultrasonic time for each time is 6 minutes; blow off the water droplets on the electrode with nitrogen; dry it in a drying oven at 80℃ to improve the adhesion of the photoresist.
[0049] Take AZ5214 positive photoresist and add it to the center of the silicon wafer. First, spin coat it at a speed of 500 r / min for 5 seconds, and then spin coat it at a speed of 2000 r / min for 65 seconds. Place the silicon wafer on a heating table and dry it at 150°C for 2 minutes to solidify the solvent in the photoresist.
[0050] Place the above silicon wafer on the workbench of the electron beam lithography machine and fix it; import the electrode pattern drawn by I-edit software into the lithography machine, and start the lithography machine for lithography; place the photoresist / silicon wafer after lithography in the developer, and take it out after 2 minutes of development; use deionized water to wash and remove the residual developer in the graphic area; place the exposed silicon wafer in a buffered hydrofluoric acid solution and etch for 25 seconds; use deionized water to wash the silicon wafer 6 times to remove the etching solution.
[0051] Titanium and gold films are deposited on the silicon wafer by electron beam evaporation; the coated silicon wafer is cleaned with AZ degumming liquid to remove the photoresist-gold film composite structure to obtain a patterned electrode.
[0052] (2) Substrate treatment
[0053] Take a 1cm×1cm×1.5mm silicon wafer electrode; use acetone, anhydrous ethanol and deionized water to ultrasonically clean the electrode in turn to remove oil and impurities on the surface of the silicon wafer electrode. Each ultrasonic cleaning time is 6 minutes; blow off the water droplets on the electrode with nitrogen gas, and dry it in a drying oven at 60°C. Then use plasma or ozone cleaning for 15 minutes to increase the hydrophilicity of the substrate surface.
[0054] (3) Preparation of single-layer MoS2 film
[0055] Take a MoS2 block material, place it on a certain length of 3M tape, take another piece of 3M tape to stick it to it, press it gently and peel it off at a uniform speed, repeat this step until the MoS2 sample becomes thinner. Take a 4mm×4mm polydimethylsiloxane (PDMS) sheet and stick it to the center of a clean glass slide; stick the 3M tape with a thin layer of MoS2 to the PDMS surface, press it gently and remove it, and place it under an optical microscope to observe the morphology of MoS2. Repeat the above peeling operation until almost transparent MoS2 is observed on the PDMS, and a single-layer MoS2 film is obtained.
[0056] (4) Preparation of single-layer MoS2 thin film devices
[0057] The single-layer MoS2 film / PDMS / glass slide prepared above was fixed to the rotating bracket of the three-dimensional transfer platform, the position of the sample to be transferred was found through an optical microscope, and it was moved to the center of the field of view.
[0058] Place the silicon wafer with electrodes on the heating table, turn on the vacuum adsorption device, adjust the knob of the three-dimensional transfer platform, align the sample with the electrode on the silicon wafer and slowly press down; further reduce the pressing speed after the bonding line between PDMS and the silicon wafer appears in the field of view, and heat at 70℃ for 1-2 minutes after PDMS and the silicon wafer are completely bonded. Slowly lift the glass slide and transfer the single-layer MoS2 to the target electrode area to obtain a single-layer MoS2 device.
[0059] The above-mentioned single-layer MoS2 device was placed in a tube furnace and annealed at 220°C for 30 minutes to improve the contact performance between the Au / Cr electrode and the single-layer MoS2 film and reduce the adhesion of molecules such as H2O and O2 to the single-layer MoS2 film.
[0060] (5) Preparation of MoS2 quantum dots
[0061] Prepare sodium molybdate solution: dissolve 0.25 g of sodium molybdate (Na2MoO4·2H2O) in 25 mL of deionized water, ultrasonicate for 5 min to make it evenly dispersed, and add 0.1 M hydrochloric acid to adjust the pH value of the sodium molybdate solution to 6.5.
[0062] Preparation of L-cysteine solution: Dissolve 0.5 g of L-cysteine in 50 mL of deionized water and treat with ultrasound for 10 min.
[0063] The two solutions were mixed and transferred to a 100 mL tetrafluoroethylene liner, then placed in a reactor and reacted at 200°C for 36 hours. After the solution was cooled to room temperature naturally, it was centrifuged at 12000 r / min for 30 minutes, and then the light brown supernatant was collected to obtain MoS2 quantum dots. TEM characterization of quantum dots Figure 1As shown. The quantum dots are close to spherical, and the average size is about 2.8nm, showing a typical quantum confinement effect. At the same time, the HRTEM illustration shows that the synthesized MoS2 quantum dots have clear lattice edges, highly ordered parallel line characteristics, and a lattice spacing of 0.276nm. These results show that MoS2 quantum dots with high crystalline quality have been successfully synthesized.
[0064] (6) Preparation of homojunction photoelectric sensors
[0065] Take 200 μL of the supernatant of MoS2 quantum dots and drop it onto the silicon wafer electrode carrying a single layer of MoS2. -1 The silicon wafer electrode was then placed in a tube furnace, annealed at 220°C for 30 min under nitrogen. The high temperature and oxygen-free environment can eliminate the corrosion effect of the organic solvent in the MoS2 quantum dot solution on the surface of the single-layer MoS2, and a high-quality homojunction photoelectric sensor is obtained. The actual device and the structural schematic are shown in Figure 1. Figure 2 shown.
[0066] The single-layer MoS2 device prepared in step (4) was used as a control example to compare the photoelectric detection performance with the homojunction photoelectric sensor prepared in step (6).
[0067] By testing the dynamic response characteristics of the photoelectric sensor, we can understand the stability of the device and the light response speed of the device under periodic light changes. Figure 3 As can be seen from the light response diagram (a) in the figure, the homojunction photoelectric sensor prepared in this embodiment has good stability and reproducible switching characteristics. The rise time and fall time are used to analyze the light response speed, that is, the duration of the response signal from 20% to 80% of the maximum value. Figure 3 (b) It can be seen that the average rise time of the homojunction photoelectric sensor prepared in this embodiment under the irradiation of a laser with a wavelength of 532nm is 24.06ms, and the fall time is 46.82ms. This phenomenon shows that the addition of quantum dots enables the device to generate and collect more photoelectricity, thereby improving the performance of the device.
[0068] Use semiconductor parameter analyzer to study the electrical properties of homojunction at different wavelengths, such as Figure 4 As shown in the figure, after adding quantum dots, the photosensor shows outstanding responsiveness in the visible light range, and the light absorption and electron transport processes are significantly improved, thereby increasing the sensitivity to light signals. In particular, under the irradiation of light with a wavelength of 532nm, the responsiveness of the homojunction device reaches 27.6AW -1 , the detection rate reaches 2.13×10 11Jones. After hybridizing quantum dots at the same time, the device's responsiveness and detection rate are improved across the entire wavelength spectrum. This is because MoS2 quantum dots have a strong light absorption capacity in the ultraviolet band due to their small size and discrete energy levels, while single-layer MoS2 exhibits a strong absorption capacity from visible light to near-infrared light. The combination of the two materials to form a composite structure will produce a synergistic effect, expanding the material's light absorption range, thereby achieving a wide-spectrum light response from ultraviolet to near-infrared.
[0069] from Figure 5 The principle of the homojunction device can be further explored in the energy band diagram shown. The monolayer MoS2 and MoS2 quantum dots form a type I band arrangement at the interface. Since the Fermi level of MoS2 quantum dots is higher than that of monolayer MoS2, in the process of forming an internal electric field, the free electrons in the MoS2 quantum dots will move toward the monolayer MoS2 until an equilibrium state with the same Fermi level is reached. This band arrangement enables the device to effectively collect charge carriers under the action of an external electric field. At the same time, due to the difference in Fermi level, a local electric field is generated at the interface, which helps the separation of charge carriers. Therefore, this improves the response performance of the photosensor.
[0070] Embodiment 2:
[0071] (1) Preparation of patterned electrodes
[0072] Take a 1cm×1cm×1.5mm silicon wafer with an oxide layer thickness of 300nm; use acetone, anhydrous ethanol and deionized water to ultrasonically clean the silicon wafer in turn to remove oil and impurities on the surface of the silicon wafer, and the ultrasonic time for each time is 6 minutes; blow off the water droplets on the electrode with nitrogen; dry it in a drying oven at 80℃ to improve the adhesion of the photoresist.
[0073] Take AZ5214 positive photoresist and add it to the center of the silicon wafer. First, spin coat it at a speed of 500 r / min for 5 seconds, and then spin coat it at a speed of 2000 r / min for 65 seconds. Place the silicon wafer on a heating table and dry it at 150°C for 2 minutes to solidify the solvent in the photoresist.
[0074] Place the above silicon wafer on the workbench of the electron beam lithography machine and fix it; import the electrode pattern drawn by I-edit software into the lithography machine, and start the lithography machine for lithography; place the photoresist / silicon wafer after lithography in the developer, and take it out after 2 minutes of development; use deionized water to wash and remove the residual developer in the graphic area; place the exposed silicon wafer in a buffered hydrofluoric acid solution and etch for 25 seconds; use deionized water to wash the silicon wafer 6 times to remove the etching solution.
[0075] Titanium and gold films are deposited on the silicon wafer by electron beam evaporation; the coated silicon wafer is cleaned with AZ degumming liquid to remove the photoresist-gold film composite structure to obtain a patterned electrode.
[0076] (2) Substrate treatment
[0077] Take a 1cm×1cm×1.5mm silicon wafer electrode;
[0078] Use acetone, anhydrous ethanol and deionized water to ultrasonically clean the electrode in turn to remove oil and impurities on the surface of the silicon wafer electrode. The ultrasonic cleaning time is 8 minutes each time. Blow off the water droplets on the electrode with nitrogen. Dry in a drying oven at 70°C. Then plasma or ozone cleaning for 10 minutes to increase the hydrophilicity of the substrate surface.
[0079] (3) Preparation of single-layer MoS2 film
[0080] Take a MoS2 block material, place it on a certain length of 3M tape, take another piece of 3M tape to stick it to it, press it gently and peel it off at a uniform speed, repeat this step until the MoS2 sample becomes thinner. Take a 4mm×4mm polydimethylsiloxane (PDMS) sheet and stick it to the center of a clean glass slide; stick the 3M tape with a thin layer of MoS2 to the PDMS surface, press it gently and remove it, and place it under an optical microscope to observe the morphology of MoS2. Repeat the above peeling operation until almost transparent MoS2 is observed on the PDMS, and a single-layer MoS2 film is obtained.
[0081] (4) Preparation of single-layer MoS2 thin film devices
[0082] The single-layer MoS2 film / PDMS / glass slide prepared above was fixed to the rotating bracket of the three-dimensional transfer platform, the position of the sample to be transferred was found through an optical microscope, and it was moved to the center of the field of view.
[0083] Place the silicon wafer with electrodes on the heating table, turn on the vacuum adsorption device, adjust the knob of the three-dimensional transfer platform, align the sample with the electrode on the silicon wafer and slowly press down; further reduce the pressing speed after the bonding line between PDMS and the silicon wafer appears in the field of view, and heat at 80℃ for 1-2 minutes after PDMS and the silicon wafer are completely bonded. Slowly lift the glass slide and transfer the single-layer MoS2 to the target electrode area to obtain a single-layer MoS2 device.
[0084] The above-mentioned single-layer MoS2 device was placed in a tube furnace and annealed at 220°C for 25 minutes to improve the contact performance between the Au / Cr electrode and the single-layer MoS2 film and reduce the adhesion of molecules such as H2O and O2 to the single-layer MoS2 film.
[0085] (5) Preparation of MoS2 quantum dots
[0086] Prepare sodium molybdate solution: dissolve 0.25 g of sodium molybdate (Na2MoO4·2H2O) in 25 mL of deionized water, perform ultrasonic treatment for 10 min to make it evenly dispersed, and add 0.1 M hydrochloric acid to adjust the pH value of the sodium molybdate solution to 6.5.
[0087] To prepare an L-cysteine solution, 0.5 g of L-cysteine was dissolved in 50 mL of deionized water and ultrasonically treated for 15 min.
[0088] The two solutions were mixed and transferred to a 100 mL tetrafluoroethylene liner, then placed in a reactor and reacted at 210°C for 36 hours. After the solution was cooled to room temperature naturally, it was centrifuged at 11000 r / min for 30 minutes, and then the light brown supernatant was collected to obtain MoS2 quantum dots.
[0089] (6) Preparation of homojunction photoelectric sensors
[0090] Take 150 μL of the supernatant of MoS2 quantum dots and drop it onto the silicon wafer electrode containing a single layer of MoS2. -1 The silicon wafer was spin-coated at a speed of 30s, transferred to a heating table, and dried at 80℃ for 10min. The silicon wafer electrode was then placed in a tube furnace, ventilated with nitrogen, and annealed at 220℃ for 30min. High-temperature oxygen-free treatment can eliminate the corrosion effect of organic solvents in the MoS2 quantum dot solution on the surface of the monolayer MoS2, and obtain high-quality homojunction photoelectric sensors.
[0091] The embodiments are preferred implementations of the present invention, but the present invention is not limited to the above-mentioned implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essential content of the present invention belong to the protection scope of the present invention.
Claims
1. A method for preparing a 0D / 2D homojunction photoelectric sensor based on MoS2, characterized in that: The steps include: Step 1: preparing a patterned silicon wafer electrode; Step 2: Prepare a single-layer MoS2 film by mechanical exfoliation, and transfer the obtained single-layer MoS2 film to the processed patterned silicon wafer electrode by dry method; Step 3: Prepare sodium molybdate solution: dissolve sodium molybdate in deionized water, dissolve by ultrasonication, and then add hydrochloric acid to adjust the pH value of the sodium molybdate solution to 6-6.5; Prepare L-cysteine solution: dissolve L-cysteine in deionized water and dissolve by ultrasonication; Step 4: Mix the sodium molybdate solution and the L-cysteine solution, then transfer to a polytetrafluoroethylene reactor, and react at 180-200° C. for 36-38 hours; after cooling to room temperature, centrifuge at a speed of 11000-12000 r / min for 30-40 minutes to obtain a MoS2 quantum dot supernatant; Step 5: Spin-coat the MoS2 quantum dot supernatant onto the monolayer MoS2 film on the patterned silicon wafer electrode, dry at 70-80°C for 10-13 min, pass nitrogen gas and anneal at 200-220°C for 20-30 min to obtain a MoS2-based 0D / 2D homojunction photoelectric sensor.
2. The method for preparing a 0D / 2D homojunction photoelectric sensor based on MoS2 according to claim 1, characterized in that: In step 1, the substrate is a patterned silicon wafer electrode, and the preparation steps of the electrode include: Step 1.1 Take a 1cm×1cm×1.5mm silicon wafer with an oxide layer thickness of 300nm; Step 1.2: ultrasonically clean the silicon wafer using acetone, anhydrous ethanol and deionized water in sequence to remove oil and impurities on the surface of the silicon wafer. The ultrasonic cleaning time for each cleaning is 5 to 8 minutes. Step 1.3 Use nitrogen to blow off the water droplets on the electrode; Step 1.4 Drying in a drying oven at 60-80°C to improve the adhesion of the photoresist; Step 1.5: Take AZ5214 positive photoresist and drop it on the center of the silicon wafer. Spin it at 500 r / min for 5-10 s, and then spin it at 2000 r / min for 60-65 s. Step 1.6: Place the silicon wafer on a heating table and dry it at 120-150°C for 1-2 minutes to solidify the solvent in the photoresist; Step 1.7: Place the silicon wafer on the workbench of the electron beam lithography machine and fix it; Step 1.8 Import the electrode pattern drawn by I-edit software into the photolithography machine and start the photolithography machine for photolithography; Step 1.9: Place the photoresist / silicon wafer after photolithography in a developer and take it out after developing for 1 to 2 minutes; Step 1.10: Use deionized water to clean and remove the residual developer in the graphic area; Step 1.11: Place the exposed silicon wafer in a buffered hydrofluoric acid solution and etch for 20 to 25 seconds; Step 1.12: Rinse the silicon wafer 5 to 6 times with deionized water to remove the etching solution; Step 1.13 depositing titanium and gold films on the silicon wafer by electron beam evaporation; Step 1.14: Use AZ degumming solution to clean the coated silicon wafer, remove the photoresist-gold film composite structure, and obtain a patterned silicon wafer electrode.
3. The method for preparing the 0D / 2D homojunction photoelectric sensor based on MoS2 according to claim 2, characterized in that: In step 2, the patterned silicon wafer electrode is subjected to the following treatments before transferring the single-layer MoS2 film: Step 2.1: ultrasonically clean the substrate using acetone, anhydrous ethanol and deionized water in sequence to remove oil and impurities on the surface of the silicon wafer, with each ultrasonic cleaning lasting 5 to 8 minutes; Step 2.2 Blow off the water droplets on the substrate with nitrogen; Step 2.3 Drying in a drying oven at 60-80°C; Step 2.4: Plasma or ozone cleaning for 10 to 20 minutes to increase the hydrophilicity of the substrate surface.
4. The method for preparing the 0D / 2D homojunction photoelectric sensor based on MoS2 according to claim 2, characterized in that: In step 1, the heating temperature of the dry transfer is 70-80° C., and the heating time is 1-2 min.
5. The method for preparing a 0D / 2D homojunction photoelectric sensor based on MoS2 according to claim 1, characterized in that: In step 2, the amounts of sodium molybdate and deionized water in the sodium molybdate solution are 0.25 g and 25 mL, respectively, and the solution is ultrasonicated for 5 to 8 min; and the molar concentration of hydrochloric acid is 0.1 mol / L.
6. The method for preparing a 0D / 2D homojunction photoelectric sensor based on MoS2 according to claim 1, characterized in that: In step 2, the amounts of L-cysteine and deionized water in the L-cysteine solution are 0.5 g and 50 mL, respectively, and the solution is sonicated for 10 to 12 minutes.
7. The method for preparing a 0D / 2D homojunction photoelectric sensor based on MoS2 according to claim 1, characterized in that: The spin coating in step 4 is to take 100-200 μL of the supernatant of MoS2 quantum dots and drop it onto the monolayer MoS2 film with a substrate, and spin coat it at a speed of 2000-3000 r / min for 20-30 seconds.
8. The 0D / 2D homojunction photoelectric sensor based on MoS2 prepared by the preparation method according to any one of claims 1 to 7, characterized in that: It comprises a substrate, an electrode, a single-layer MoS2 thin film layer and a MoS2 quantum dot layer, wherein the single-layer MoS2 thin film layer and the MoS2 quantum dot layer are sequentially stacked in a channel structure formed by the electrode.