Artificial photoelectric neuron memristor with double conductive wires and manufacturing method of artificial photoelectric neuron memristor

Abstract

The invention discloses an artificial photoelectric neuron memristor with double conductive wires and a manufacturing method of the artificial photoelectric neuron memristor. The memristor device sequentially comprises a substrate, a resistance change layer, a light absorption layer and a top electrode from bottom to top, the substrate is a bottom electrode of a P-type highly-doped pure silicon wafer, the resistance change layer is an oxide thin film layer, the light absorption layer is a P-type organic semiconductor polymer thin film layer, and the top electrode is a thermally evaporated silver electrode. According to the artificial photoelectric neuron memristor device manufactured by the invention, the material of the resistance change layer is the oxide, the oxide material is rich in oxygen vacancies, and the oxygen vacancies contribute to the formation of the conductive wires in the process of forming the conductive wires, so that the finally formed conductive wires are formed by the silver clusters and the oxygen vacancies, and compared with pure silver conductive wires, the resistance change layer has the advantages that the resistance change layer is more uniform; the composite conductive wire is formed faster, the required forward threshold voltage is lower, the device can simulate the refractory behavior in neurons, the performance can be adjusted through illumination, and the performance can be improved to a certain extent under the illumination condition.

Description

Technical Field

[0001] The invention belongs to the technical field of organic semiconductor device manufacturing, and in particular relates to an artificial photoelectric neuron memristor with double conductive filaments and a manufacturing method thereof. Background Art

[0002] Due to the rapid development of information technology, there is an urgent need to efficiently process complex tasks such as learning, perception, memory and reasoning. In recent years, neuromorphic computing has attracted widespread attention because of its ability to process massive amounts of data with extremely low power consumption. As an important component of artificial neuromorphic computing, artificial neurons receive and integrate input signals transmitted from synapses, and generate spike signals as outputs when the threshold is exceeded. Usually, the function of artificial neurons is fitted into a threshold function to determine whether the synaptic signal is fully integrated to reach the threshold. Most artificial neurons receive the previous postsynaptic current as input and output voltage to the next synaptic front end in the form of spikes, just like biological neurons discharge, to achieve information exchange. At present, artificial neurons based on memristors have the advantages of high stacking density, low power consumption, and fast switching speed, which are closer to biological neurons in nature.

[0003] In many complex neuromorphic calculations, artificial neurons need to have adjustable performance to adapt to complex environments. Most of the current artificial neurons rely mainly on electrical signal drive. However, electrical stimulation signals have some disadvantages such as high power consumption, limited triggering options, and difficulty in simulating visual systems, making it difficult to further improve computing speed and energy efficiency. Compared with electrical signals, optical signals have significant advantages in high energy efficiency, high bandwidth, low crosstalk, and computing speed. Therefore, memristor neurons can be regulated through the photoelectric synergistic effect. In addition, the formation of conductive filaments during the resistive switching process is particularly important. Most of them form a single conductive filament, which makes it difficult to further improve the performance of the device. Using oxide as the resistive switching layer can form oxygen vacancy conductive filaments and silver conductive filaments. This composite conductive filament is formed faster, requires a lower threshold voltage, and has better performance. Summary of the invention

[0004] The purpose of the present invention is to provide an artificial photoelectric neuron memristor with dual conductive filaments and a method for making the same. An oxide solution is prepared and spin-coated as a resistive switching layer of the memristor. During the resistive switching process of the memristor, oxygen vacancies in the oxide help to form conductive filaments, so that the conductive filaments finally formed are composed of silver atom clusters and oxygen vacancies. Compared with pure silver conductive filaments, the composite conductive filaments are formed faster, require a lower threshold voltage, and have better performance.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows: An artificial photoelectric neuron memristor with double conductive filaments, wherein the memristor device comprises a substrate, a resistive switching layer, a light absorbing layer and a top electrode from bottom to top, wherein the substrate is a bottom electrode of a P-type highly doped pure silicon wafer, the resistive switching layer is an oxide thin film layer, the light absorbing layer is a P-type organic semiconductor polymer thin film layer, and the top electrode is a thermally evaporated silver electrode.

[0006] Furthermore, the oxide film layer is formed of zinc oxide or indium gallium zinc oxide.

[0007] Furthermore, the P-type organic semiconductor polymer is indenodithiophene co-benzothiadiazole copolymer (IDT-BT) or poly-3,6-dithiophene-2-yl-2,5-di(2-decyltetradecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thiophenevinylthiophene-2,5-diyl (PDVT-10) and the like.

[0008] Furthermore, the thickness of the resistive layer is 20-100 nm, the thickness of the light absorption layer is 20-100 nm, and the thickness of the top electrode is 40-60 nm.

[0009] Furthermore, the method for manufacturing the artificial photoelectric neuron memristor with double conductive filaments comprises the following steps: S1: With a P-type highly doped pure silicon wafer as the substrate, the substrate silicon wafer is placed in an ultrasonic cleaning tank and cleaned with acetone, isopropanol and deionized water for 5 to 10 minutes in sequence. Immediately after cleaning, the residual liquid on the surface of the substrate is blown dry with a nitrogen spray gun. The cleaned silicon wafer is then treated with an oxygen plasma power of 640 to 680 W for 10 to 15 minutes to improve the hydrophilicity of the surface. S2: preparing an oxide thin film layer solution as a resistive switching layer material, and spin coating the resistive switching layer material on the substrate processed in step S1. After the resistive switching layer material is spin-coated into a film, the substrate is placed on a heating platform for heating treatment to obtain a resistive switching layer; S3: dissolving a P-type organic semiconductor polymer in an organic solvent, heating and stirring to obtain a light absorbing layer material, spin-coating the light absorbing layer material on the resistive layer, and placing the material on a heating table for heating treatment to obtain a light absorbing layer; S4: Evaporating silver particles onto the light absorbing layer by thermal evaporation to obtain a silver electrode.

[0010] Furthermore, the oxide film layer solution in step S2 is a zinc oxide solution, and its preparation method is: dissolving zinc acetate in dimethyl sulfoxide and stirring to dissolve to obtain liquid A, dissolving tetramethylammonium hydroxide in ethanol, stirring to dissolve to obtain liquid B, mixing liquid A and liquid B, heating in a water bath, then adding ethyl acetate, centrifuging, and finally adding n-butanol to dissolve the precipitate to obtain a zinc oxide solution.

[0011] Furthermore, the oxide film layer solution in step S2 is an indium gallium zinc oxide solution, and its preparation method is: indium nitrate, gallium nitrate and zinc acetate dihydrate are added into ethylene glycol methyl ether as indium source, gallium source and zinc source respectively, and stirred and dissolved, and then ethanolamine is added as a stabilizer. After stirring at room temperature for 4 hours, the solution is allowed to stand overnight to obtain an indium gallium zinc oxide solution.

[0012] Furthermore, in step S3, the organic solvent is chlorobenzene solvent, the temperature of heating and stirring is 60-65° C., and the time is 2-2.5 hours.

[0013] Compared with the prior art, the memristor prepared by the present invention does not require a cumbersome preparation process, and can achieve the function of simulating artificial neurons only through a solution method, and has the following advantages: 1. Oxide materials are rich in oxygen vacancies. In the process of forming conductive filaments, oxygen vacancies help to form conductive filaments, so that the finally formed conductive filaments are composed of silver atom clusters and oxygen vacancies. Compared with pure silver conductive filaments, this composite conductive filament is formed faster, thereby realizing the simulation of artificial neurons.

[0014] 2. The film-forming materials of the device are all solutions, which can be formed by a simple spin coating method and can be carried out in the atmosphere. The preparation process is relatively simple, convenient and low-cost.

[0015] 3. The device can adjust its performance through light, and there will be certain improvements under lighting conditions, which is in line with the current development trend of electronic equipment.

[0016] 4. The device can simulate the refractory period behavior of neurons. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a schematic diagram of the structure of the artificial photoelectric neuron memristor of the present invention: wherein 100 is the bottom electrode, 110 is the resistive layer, 120 is the light absorbing layer, and 130 is the top electrode.

[0018] Figure 2 It is a schematic diagram of the principle of the double conductive wire resistance change characteristics of the artificial photoelectric neuron memristor of the present invention.

[0019] Figure 3 3 is the IV characteristic curve of the artificial photoelectric neuron memristor prepared in Example 1.

[0020] Figure 4 This is the integration-firing behavior of the artificial photoelectric neuron memristor prepared in Example 1.

[0021] Figure 5 This is the IV characteristic curve of the artificial photoelectric neuron memristor prepared in Example 1 after illumination.

[0022] Figure 6 This is the refractory period behavior of the neuron simulated by the artificial photoelectric neuron memristor prepared in Example 1. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings.

[0024] like Figure 1 As shown, an artificial optoelectronic neuron memristor with dual conductive filaments, the memristor device includes a substrate 100, a resistive layer 110, a light absorbing layer 120 and a top electrode 130 from bottom to top, the substrate is a bottom electrode of a P-type highly doped pure silicon wafer, the resistive layer is an oxide film layer, the light absorbing layer is a P-type organic semiconductor polymer film layer, and the top electrode is a thermally evaporated silver electrode.

[0025] Furthermore, the oxide film layer is formed of zinc oxide or indium gallium zinc oxide.

[0026] Furthermore, the P-type organic semiconductor polymer is indenodithiophene-benzothiadiazole copolymer IDT-BT or PDVT-10.

[0027] Furthermore, the thickness of the resistive layer is 20-100 nm, the thickness of the light absorption layer is 20-100 nm, and the thickness of the top electrode is 40-60 nm.

[0028] Furthermore, the method for manufacturing the artificial photoelectric neuron memristor with double conductive filaments comprises the following steps: S1: With a P-type highly doped pure silicon wafer as the substrate, the substrate silicon wafer is placed in an ultrasonic cleaning tank and cleaned with acetone, isopropanol and deionized water for 5 to 10 minutes in sequence. Immediately after cleaning, the residual liquid on the surface of the substrate is blown dry with a nitrogen spray gun. The cleaned silicon wafer is then treated with an oxygen plasma power of 640 to 680 W for 10 to 15 minutes to improve the hydrophilicity of the surface. S2: preparing an oxide thin film layer solution to obtain a resistive switching layer material, and spin coating the resistive switching layer material on the substrate processed in step S1. After the resistive switching layer material is spin-coated into a film, the substrate is placed on a heating platform for heating treatment to obtain a resistive switching layer; S3: dissolving a P-type organic semiconductor polymer in an organic solvent, heating and stirring for 2 to 2.5 hours to obtain a light absorbing layer material, spin-coating the light absorbing layer material on the resistive layer, and placing the material on a heating table for heating treatment to obtain a light absorbing layer; S4: Evaporating silver particles onto the light absorbing layer by thermal evaporation to obtain a silver electrode. Example 1

[0029] A method for manufacturing an artificial photoelectric neuron memristor with double conductive filaments comprises the following steps: 1) Place a substrate silicon wafer of approximately 2.0 cm × 2.0 cm in an ultrasonic cleaning tank and clean it with acetone, isopropanol, and deionized water for 5 minutes in sequence. Immediately after cleaning, use a nitrogen spray gun to blow dry any liquid remaining on the substrate surface; 2) The cleaned silicon wafer was treated with 640 W oxygen plasma power for 10 minutes to improve the hydrophilicity of the surface; 3) Prepare ZnO solution as the resistive layer material. Use a weighing balance to take 0.6585g of zinc acetate and 0.9062g of tetramethylammonium hydroxide and pour them into two bottles respectively. Use a pipette to take 30ml of dimethyl sulfoxide and pour it into the bottle containing zinc acetate. Stir and dissolve to obtain liquid A. Take 10ml of ethanol and pour it into the bottle containing tetramethylammonium hydroxide. Stir and dissolve to obtain liquid B. Then slowly drip liquid B into liquid A with a rubber dropper, and then heat it in a water bath at 30℃ for 1 hour to obtain a mixed solution. Then, 40ml of the mixed solution is evenly placed in two centrifuge tubes, 20ml of ethyl acetate is added to each, and the mixture is placed in a centrifuge for centrifugation. After centrifugation, the suspension is poured out, and 5ml of n-butanol is added to each centrifuge tube to dissolve the precipitate. Finally, the zinc oxide solution is filtered out with a syringe filter. The zinc oxide solution was spin-coated on the silicon wafer substrate using a spin coater at 3000 rpm for 40 seconds, and then annealed on a heating table at 100 °C for 0.5 hours to obtain a resistive switching layer with a thickness of 20-100 nm. 4) Prepare a P-type organic semiconductor polymer solution as the light-absorbing layer material, weigh 15 mg of IDT-BT on a weighing balance and put it into a bottle for later use, use a pipette to take 1 ml of chlorobenzene solvent, add it to the above bottle, heat and stir at 60 ° C on a magnetic stirring table for 2 hours, spin-coat 15 mg / ml IDTBT solution at 1500 rpm for 60 seconds to coat the light-absorbing layer material on the resistive layer, and then place it on a heating table for annealing at 120 ° C for 10 minutes to obtain a light-absorbing layer with a thickness of 20~100 nm; 5) Evaporate 40-60nm thick silver on the IDT-BT film through a shadow mask as the top electrode.

[0030] The resistance switching characteristics of the double conductive wire of the artificial optoelectronic neuron memristor prepared in Example 1 are as follows: Figure 2 As shown, it shows that the oxide acts as a resistive switching layer. During the resistive switching process of the memristor, the oxygen vacancies in the oxide help to form a conductive filament, so that the conductive filament finally formed is a double conductive filament composed of silver atom clusters and oxygen vacancies. The IV characteristic curve of the memristor is shown in Figure 3 As shown, the threshold voltage is 1.99V. The integration-ignition behavior is as follows Figure 4 As shown in the figure, under the stimulation of a certain number of electrical pulses, the neuron device reaches the threshold and is activated, changing from a high-resistance state to a low-resistance state. The IV characteristic curve after illumination is shown in the figure below. Figure 5As shown in Figure 2, the threshold voltage of the memristor is reduced from 1.99V to 1.62V, indicating that the performance of the device can be adjusted by light. The refractory period behavior of the simulated neuron is shown in Figure 2. Figure 6 As shown in the figure, it means that after the neuron is activated, the neuron device will not respond even if the stimulus is continued for a certain period of time, and the device will continue to be activated after a period of time, which corresponds to the refractory period behavior of the neuron, indicating that the device can simulate the neuron well. Therefore, this work provides a new form of artificial neurons and brings new development ideas to neural network computing. Example 2

[0031] A method for manufacturing an artificial photoelectric neuron memristor with double conductive filaments comprises the following steps: 1) Place a substrate silicon wafer of approximately 2.0 cm × 2.0 cm in an ultrasonic cleaning tank and clean it with acetone, isopropanol, and deionized water for 5 minutes in sequence. Immediately after cleaning, use a nitrogen spray gun to blow dry any liquid remaining on the substrate surface; 2) The cleaned silicon wafer was treated with 640 W oxygen plasma power for 10 minutes to improve the hydrophilicity of the surface; 3) According to the molar ratio of In:Ga:Zn=1:24:5, weigh 24.07 mg of indium nitrate, 491.02 mg of gallium nitrate and 87.8 mg of zinc acetate dihydrate respectively for use. Then use a 1000 microliter pipette to take 1 ml of ethylene glycol methyl ether into a reagent bottle. Then, add gallium nitrate to the solvent ethylene glycol methyl ether, add a stirrer and stir with a magnetic stirrer until it is clear and transparent, then add indium nitrate and continue stirring until it is clear and transparent, and finally add zinc acetate dihydrate and stir until the solution is clear and transparent. After the three raw materials are completely dissolved, add 30 microliters of stabilizer ethanolamine and stir at room temperature for 4 hours. Let the stirred solution stand overnight to obtain a colorless and transparent IGZO precursor solution. After that, use a rubber-tipped dropper to absorb an appropriate amount of precursor solution and drop it on the cleaned silicon wafer. Set up multi-step spin coating. The first step is set at 500rpm for 5s to evenly spread the solution on the silicon wafer. The second step is set at 3000rpm for 40s to obtain a uniform wet film. Then place the coated silicon wafer on a heating table at 180℃ for 10min pre-annealing, and then place it on a heating table at 350℃ for high-temperature annealing for 1h, and finally obtain a uniform IGZO film with a thickness of about 20~100nm.

[0032] 4) Prepare a P-type organic semiconductor polymer solution as the light-absorbing layer material. Weigh 15 mg of PDVT-10 on a weighing balance and put it into a bottle for later use. Use a pipette to take 1 ml of chlorobenzene solvent and add it to the above bottle. Heat and stir at 60 °C on a magnetic stirring table for 2 hours. Spin coat the 15 mg / ml PDVT-10 solution at 1000 rpm for 60 seconds to evenly coat the light-absorbing layer material on the resistive layer. Then place it on a heating table and anneal it at 100 °C for 10 minutes to obtain a light-absorbing layer with a thickness of 20~100 nm.

[0033] 5) Evaporate 40-60nm thick silver on the PDVT-10 film through a shadow mask as the top electrode.

[0034] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be regarded as equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An artificial photoelectric neuron memristor with double conductive filaments, characterized in that: The memristor device comprises a substrate, a resistive switching layer, a light absorbing layer and a top electrode from bottom to top, wherein the substrate is a bottom electrode of a P-type highly doped pure silicon wafer, the resistive switching layer is an oxide thin film layer, the light absorbing layer is a P-type organic semiconductor polymer thin film layer, and the top electrode is a thermally evaporated silver electrode.

2. The artificial photoelectric neuron memristor with double conductive filaments according to claim 1, characterized in that: The oxide film layer is formed of zinc oxide or indium gallium zinc oxide.

3. The artificial photoelectric neuron memristor with double conductive filaments according to claim 1, characterized in that: The P-type organic semiconductor polymer is an indenodithiophene co-benzothiadiazole copolymer or poly-3,6-dithiophene-2-yl-2,5-di(2-decyltetradecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thienylvinylthiophene-2,5-diyl (PDVT-10).

4. The artificial photoelectric neuron memristor with double conductive filaments according to claim 1, characterized in that: The thickness of the resistive layer is 20-100 nm, the thickness of the light absorption layer is 20-100 nm, and the thickness of the top electrode is 40-60 nm.

5. The method for manufacturing a double conductive filament artificial optoelectronic neuron memristor according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: Using a P-type highly doped pure silicon wafer as the substrate, the substrate silicon wafer is placed in an ultrasonic cleaning tank for cleaning. Immediately after cleaning, a nitrogen spray gun is used to blow dry the residual liquid on the substrate surface. The cleaned silicon wafer is then treated with an oxygen plasma power of 640-680W for 10-15 minutes to improve the hydrophilicity of the surface. S2: preparing an oxide thin film layer solution as a resistive switching layer material, and spin coating the resistive switching layer material on the substrate processed in step S1. After the resistive switching layer material is spin-coated into a film, the substrate is placed on a heating platform for heating treatment to obtain a resistive switching layer; S3: dissolving a P-type organic semiconductor polymer in an organic solvent, heating and stirring to obtain a light absorbing layer material, spin-coating the light absorbing layer material on the resistive layer, and placing the material on a heating table for heating treatment to obtain a light absorbing layer; S4: Evaporating silver particles onto the light absorbing layer by thermal evaporation to obtain a silver electrode.

6. A method for manufacturing a dual conductive filament artificial optoelectronic neuron memristor according to claim 5, characterized in that: The substrate silicon wafer is placed in an ultrasonic cleaning tank and cleaned with acetone, isopropanol and deionized water in sequence for 5 to 10 minutes.

7. A method for manufacturing a dual conductive filament artificial optoelectronic neuron memristor according to claim 5, characterized in that: The oxide film layer solution in step S2 is a zinc oxide solution, and its preparation method is as follows: zinc acetate is dissolved in dimethyl sulfoxide and stirred to dissolve to obtain liquid A, tetramethylammonium hydroxide is dissolved in ethanol, stirred to dissolve to obtain liquid B, liquid A and liquid B are mixed and heated in a water bath, then ethyl acetate is added, centrifuged, and finally n-butanol is added to dissolve the precipitate to obtain a zinc oxide solution.

8. A method for manufacturing a dual conductive filament artificial optoelectronic neuron memristor according to claim 5, characterized in that: The oxide film layer solution in step S2 is an indium gallium zinc oxide solution, and its preparation method is as follows: indium nitrate, gallium nitrate and zinc acetate dihydrate are added into ethylene glycol methyl ether as indium source, gallium source and zinc source respectively, and stirred and dissolved, and then ethanolamine is added as a stabilizer. After stirring at room temperature for 4 hours, the solution is allowed to stand overnight to obtain an indium gallium zinc oxide solution.

9. A method for manufacturing a double conductive filament artificial optoelectronic neuron memristor according to claim 5, characterized in that: In step S3, the organic solvent is chlorobenzene solvent, the heating and stirring temperature is 60-65° C., and the time is 2-2.5 hours.

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