Preparation method of ZTO fiber-based synaptic device with adjustable electrical performance

Abstract

The application discloses a preparation method of a ZTO fiber-based synapse device with adjustable electrical performance. The method is used for preparing orderable ZTO semiconductor fibers through an electrohydrodynamic printer. In the preparation process, the interval between adjacent ZTO fibers is accurately controlled by setting printing parameters according to the demand of electrical performance, the number of ZTO fibers in the same area is accurately controlled, a synapse device is further prepared, and the electrical performance of the synapse device is accurately adjusted. The method adopted by the application realizes the order arrangement of the fiber channel of the ZTO fiber-based synapse device and the accurate adjustment of the fiber interval and number, and the obtained device has the electrical performance which can be accurately prepared according to the demand, thereby providing beneficial guidance for the device design and preparation in the field of neuromorphic electronics and brain-like computing.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor devices, and specifically relates to a method for preparing a ZTO fiber-based synaptic device with tunable electrical properties. Background Technology

[0002] The human nervous system, with its advantages of high compactness, parallelism, and reliability, has attracted widespread attention in fields such as neuromorphic computing, biomimetic sensory-motor systems, brain-computer interfaces, and artificial prostheses. Somatosensory nerves transmit signals through synaptic connections, enabling various sensory, memory, and motor outputs. Therefore, to construct efficient artificial sensory-motor systems, bio-hybrid systems, and neuromorphic chips, it is essential to simulate the functions of biological synapses. Currently, scientists have designed various structures (such as memristors, electrolyte / semiconductor heterojunctions, and multi-terminal transistors) to achieve signal transmission and simulate synaptic behavior. Among these, three-terminal biomimetic synaptic devices, capable of simulating multiple functions of biological synapses, are considered one of the most promising artificial synaptic devices.

[0003] In recent years, metal oxides have attracted widespread attention as semiconductor materials. Metal oxide semiconductors, represented by zinc oxide (ZnO), possess high carrier mobility, chemical stability, and reliability, and are used in solar cells, sensors, and flat panel displays. However, their polycrystalline surface structure leads to scattering during carrier transport, degrading their electrical performance. To address these issues, multi-component oxide semiconductors such as indium zinc oxide (IZO), indium gallium zinc oxide (IGZO), and zinc tin oxide (ZTO) have been developed. Among these, ZTO is inexpensive and exhibits good compatibility with certain crystal planes of ZnO and SnO2 nanocrystals, making it commonly used in the fabrication of thin-film transistors and ultraviolet detectors. Furthermore, reports on ZTO fiber-based synaptic devices demonstrate its high application value in large-scale, highly integrated neuromorphic systems. The literature "(see IEEE Electron Device Letters, 2019, Vol. 40, pp. 1776-1779)" reports a ZTO fiber-based synaptic device. This method uses zinc chloride (ZnCl2) and stannous chloride (SnCl2) as solutes, with the addition of polyvinylpyrrolidone (PVP), and N,N-dimethylformamide (DMF) as solvent, to prepare ZTO fiber channels via electrospinning. However, the number of ZTO fibers prepared is uncontrollable and they cannot be arranged in an orderly manner. This prevents the precise selection of the number of ZTO fibers to control the electrical performance of the synaptic device, which to some extent limits its application in fields such as neuromorphic computing and artificial nervous systems. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a method for fabricating ZTO fiber-based synaptic devices with tunable electrical properties. This method involves fabricating orderly arranged ZTO semiconductor fibers using an electrohydrodynamic printer. During the fabrication process, the spacing between adjacent ZTO fibers is precisely controlled by setting printing parameters according to the electrical performance requirements (primarily the magnitude of postsynaptic current). This allows for precise control of the number of ZTO fibers within the same area, further enabling the fabrication of synaptic devices and precise control over their electrical properties. The method employed in this invention achieves the orderly arrangement of fiber channels in ZTO fiber-based synaptic devices, as well as precise control over fiber spacing and quantity. The resulting devices possess precisely customizable electrical properties, providing valuable guidance for device design and fabrication in the fields of neuromorphic electronics and brain-like computing.

[0005] The technical solution of the present invention is as follows:

[0006] A method for fabricating a ZTO fiber-based synaptic device with tunable electrical properties, comprising the following specific steps:

[0007] (1) Clean the substrate to be used with deionized water, isopropanol, acetone and anhydrous ethanol in sequence for 15-30 minutes, and then dry the substrate surface with nitrogen.

[0008] (2) Add polyvinylpyrrolidone, zinc nitrate hydrate and stannous chloride dihydrate to a mixed solvent and stir magnetically at 20-70°C for 0.5-24 hours to obtain a precursor solution;

[0009] The mixed solvent is a mixture of N,N-dimethylformamide and anhydrous ethanol in a mass ratio of 1 to 6:1, the mass ratio of polyvinylpyrrolidone:(zinc nitrate hydrate + stannous chloride dihydrate) is 1:1 to 4, the molar ratio of zinc nitrate hydrate to stannous chloride dihydrate is 7:3 to 3:7, and the mass concentration of polyvinylpyrrolidone in the precursor solution is 5% to 14%.

[0010] (3) Using an electrohydrodynamic printer, the precursor solution prepared in step (2) is printed as ZTO fibers on the substrate;

[0011] The syringe needle is subjected to a high voltage of 0.5 to 4.5 kV, the distance between the syringe needle and the substrate is 0.5 to 20 mm, the liquid flow rate of the syringe is 1 to 250 nL / min, the substrate moving speed is 50 to 1000 mm / s, the substrate temperature is 40 to 80 ℃, the printing length is 0.01 to 20 cm, and the spacing between adjacent fibers is 5 to 1000 μm.

[0012] (4) Calcine the ZTO fiber from step (3) in air at 300-700°C for 30-300 minutes, and remove it after the temperature drops to room temperature;

[0013] (5) Using a mask template, electrodes are deposited on the ZTO fiber surface obtained in step (4) as the source and drain of the synaptic device;

[0014] (6) In step (5), ionomer glue is attached to the fiber surface of the sample as the gate of the synaptic device, and finally a ZTO fiber-based synaptic device with controllable fiber quantity is made.

[0015] The method for adjusting the electrical performance of the ZTO fiber-based synaptic device is as follows: when the spacing of the ZTO fibers decreases by a multiple, the electrical performance tends to increase by a corresponding multiple, thereby increasing the peak EPSC of the ZTO fiber-based synaptic device by a corresponding multiple.

[0016] Specifically, when the spacing between nanofibers decreases by half from 100μm to 50μm, the electrical performance increases by half accordingly. Consequently, the peak EPSC of the ZTO fiber-based synaptic device under a single pulse stimulus doubles from approximately 1.16μA to 2.43μA.

[0017] The substrate in step (1) is Si / SiO2, Al2O3 or glass.

[0018] In step (5), metal electrodes with a thickness of 60-200 nm and spaced apart are deposited on the surface of ZTO fiber using a photomask as the source and drain electrodes. The metals are gold, silver, aluminum, titanium / gold, etc.

[0019] In step (6), the ionomer is chitosan, PVA, or [EMIM][TFSI], with a thickness of 0.05 to 500 μm.

[0020] The essential features of this invention are:

[0021] Fabricating ZTO semiconductor fibers using an electrohydraulic printer requires comprehensive adjustment of precursor formulation parameters and printing process parameters. Precursor formulation parameters include the concentration and proportion of the metal salt, and the mass concentration of polyvinylpyrrolidone (PVP). Printing process parameters include voltage, needle-to-substrate distance, substrate temperature, substrate movement speed, syringe flow rate, print length, and print spacing. To maintain consistent fiber size and morphology, changing one parameter necessitates coordinating the others. Therefore, in this invention, while adjusting the metal salt ratio, it is also necessary to simultaneously adjust parameters such as the mass ratio of metal salt to PPVP, the PPVP mass concentration, voltage, needle-to-substrate distance, substrate temperature, and syringe flow rate to maintain consistent fiber size and morphology.

[0022] The current method used to prepare ZTO fiber-based synaptic devices is electrospinning. The resulting ZTO fibers are randomly distributed, and the spacing between adjacent fibers cannot be precisely controlled, thus making it impossible to customize the electrical properties of the synaptic devices according to requirements.

[0023] This invention fabricates fiber channels for ZTO fiber-based synaptic devices using an electrohydrodynamic printer, achieving precise control over the ordered arrangement of ZTO fibers and the spacing between adjacent fibers. This allows for customization of the electrical properties of the synaptic devices to meet specific requirements. Specifically:

[0024] First, this invention uses an electrohydraulic printer to prepare ZTO fibers. Compared to the high voltage (greater than 10kV) and large needle-to-substrate distance (greater than 10cm) required by traditional electrospinning equipment, this method requires lower voltage (less than 4.5kV) and a closer needle-to-substrate distance (less than 2cm), offering energy-saving advantages. Furthermore, compared to the randomly distributed fibers obtained by electrospinning, this invention achieves ordered ZTO fibers through digital control of printing parameters. The spacing between adjacent ZTO fibers can be precisely controlled by setting the printing parameters. This allows for regulation: as the spacing between ZTO fibers decreases by a factor, the electrical properties increase by a corresponding factor, resulting in a corresponding increase in the EPSC peak value of the ZTO fiber-based synaptic device. Simultaneously, this invention introduces a substrate temperature parameter. Higher substrate temperatures facilitate rapid solvent evaporation in the fibers. Increasing the substrate temperature allows for ordered fiber arrangement even with higher voltage and a larger needle-to-substrate distance, making parameter settings more flexible, expanding the range of parameter selection and printing conditions. This allows for flexible selection of parameter configurations based on changes in ambient temperature and humidity.

[0025] Secondly, in existing technologies, the precursor solution uses only N,N-dimethylformamide as the solvent. This invention uses N,N-dimethylformamide and anhydrous ethanol as a mixed solvent. The boiling point of anhydrous ethanol is much lower than that of N,N-dimethylformamide, which makes the solvent more volatile during the printing process. ZTO fibers can be obtained at lower voltage, closer needle-substrate distance, lower substrate moving speed and substrate temperature, effectively reducing the energy consumption of the experimental process.

[0026] Furthermore, in this invention, the solute providing Zn atoms is zinc nitrate hydrate, whose molecular weight (297.5 g / mol) is much greater than that of zinc chloride (136.3 g / mol). This means that the mass of the solute providing the same number of Zn atoms is increased, which can relatively reduce the amount of polyvinylpyrrolidone added. Consequently, polyvinylpyrrolidone is more likely to completely volatilize during high-temperature calcination, reducing the carbon residue in ZTO fibers and obtaining purer ZTO.

[0027] The beneficial effects of this invention are as follows:

[0028] This invention presents for the first time a method for fabricating ZTO fiber-based synaptic devices with tunable electrical properties. ZTO fibers are prepared using a Huawico electrohydrodynamic printer. Compared to traditional electrospinning, the ZTO fibers prepared by this invention can be arranged in an orderly manner, and the number of fibers can be controlled by adjusting the spacing between adjacent fibers. Furthermore, this invention introduces substrate temperature as a parameter. Increasing the substrate temperature allows for the acquisition of orderly arranged fibers at higher voltages and larger needle-to-substrate distances, thus making the printing parameter settings more flexible, expanding the range of parameter selection and printing conditions. This allows for flexible selection of parameter configurations based on changes in ambient temperature and humidity. The method of this invention is simple, easy to implement, and low in cost. The prepared ZTO fiber-based synaptic devices simulate synaptic behavior, such as excitatory postsynaptic current (EPSC), double-pulse facilitation (PPF), and pulse frequency-dependent plasticity (SFDP).

[0029] By selecting the number of ZTO fibers, the electrical performance of the synaptic device can be controlled, altering the magnitude of the postsynaptic current. Precise printing of the appropriate number of ZTO fibers according to requirements allows for the customization of synaptic devices that meet specific electrical performance specifications. Adding an appropriate amount of anhydrous ethanol to N,N-dimethylformamide to prepare a mixed solvent effectively lowers the solvent's boiling point, thereby reducing the voltage applied to the printing needle, the distance between the needle and the substrate, the substrate's moving speed, and the substrate temperature. This significantly reduces energy consumption during the experiment and yields orderly arranged ZTO fibers. Furthermore, using zinc nitrate hydrate as the solute to provide Zn atoms effectively reduces the amount of polyvinylpyrrolidone used, thus reducing carbon residue in the ZTO fibers after high-temperature calcination and obtaining purer ZTO fibers. This invention overcomes the shortcomings of existing technologies and has significant implications for fields such as neuromorphic computing and artificial nervous systems. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the printing trajectory of ZTO fibers in this invention;

[0031] Figure 2 These are ZTO fiber optic microscopy images with different spacings from Example 1; wherein, Figure 2 (a) is an optical microscope image with a fiber spacing of 50 μm. Figure 2 (b) is an optical microscope image with a fiber spacing of 100 μm;

[0032] Figure 3 These are scanning electron microscope images of ZTO fibers prepared using the traditional electrospinning method.

[0033] Figure 4 This is a schematic diagram of the structure of a ZTO fiber-based synaptic device;

[0034] Figure 5 These are excitatory postsynaptic current (EPSC) test diagrams of ZTO fiber-based synaptic devices with different fiber counts in Example 1; wherein, Figure 5 (a) is the EPSC of a ZTO fiber-based synaptic device with a fiber spacing of 50 μm. Figure 5 (b) is the EPSC of a ZTO fiber-based synaptic device with a fiber spacing of 100 μm;

[0035] Figure 6 These are test images of the two-pulse facilitated (PPF) tests of ZTO fiber-based synaptic devices with different fiber counts in Example 1; wherein, Figure 6 (a) is the PPF of a ZTO fiber-based synaptic device with a fiber spacing of 50 μm. Figure 6 (b) is the PPF of a ZTO fiber-based synaptic device with a fiber spacing of 100 μm;

[0036] Figure 7 These are pulse frequency-dependent plasticity (SFDP) test diagrams based on different numbers of ZTO fiber-based synaptic devices in Example 1; wherein, Figure 7 (a) is an SFDP of a ZTO fiber-based synaptic device with a fiber spacing of 50 μm. Figure 7 (b) SFDP of ZTO fiber-based synaptic device with a fiber spacing of 100 μm;

[0037] The present invention will be further described below with reference to the accompanying drawings and embodiments, but is not limited thereto.

[0038] In this invention, the substrate moves at a set high speed to print straight and continuous ZTO fibers. The printing trajectory is a long serpentine shape, as shown in the attached figure. Figure 1 As shown, 'a' represents the length of the printed fiber, and 'b' represents the spacing between adjacent fibers. By setting the distance of segment 'b', the spacing between adjacent fibers can be precisely controlled. The fibers printed along the trajectory are arranged in an orderly manner, and within the same range, the smaller the spacing, the more fibers there are. That is, adjusting the distance of segment 'b' can precisely control the number of printed fibers. Furthermore, the electrical performance of the synaptic device can be controlled by selecting the number of ZTO fibers. By printing an appropriate number of ZTO fibers according to requirements, a biomimetic synaptic device that meets the electrical performance requirements can be customized. Detailed Implementation

[0039] Example 1

[0040] (1) The Si / SiO2 substrate to be used was ultrasonically cleaned for 30 minutes in sequence with deionized water, isopropanol, acetone and anhydrous ethanol, and then the substrate surface was dried with nitrogen.

[0041] (2) Prepare a mixed solvent by mixing N,N-dimethylformamide and anhydrous ethanol in a mass ratio of 2:1; dissolve reagents with a mass ratio of polyvinylpyrrolidone:(zinc nitrate hydrate + stannous chloride dihydrate) = 1:1.5 and a molar ratio of zinc nitrate hydrate:stannous chloride dihydrate = 7:3 in the mixed solvent, and stir at 50°C for 6 hours using a magnetic stirrer to prepare the precursor solution required for printing. The mass concentration of polyvinylpyrrolidone in the precursor solution is 10%.

[0042] (3) Using a Huawico electrohydrodynamic printer, the precursor solution prepared in step (2) was printed into ZTO fibers. During printing, a high voltage of 0.65kV was applied to the syringe needle, the distance from the syringe needle to the substrate was set to 3mm, the liquid flow rate of the syringe was set to 50nL / min, the moving speed of the substrate was set to 350mm / s, the substrate temperature was set to 40℃, the printing length was set to 20cm, and the spacing between adjacent fibers was set to sample A = 50μm and sample B = 100μm, respectively.

[0043] (4) The fiber obtained from printing in step (3) is calcined at 500°C in air for 120 minutes to finally obtain ZTO fiber;

[0044] (5) Using a photomask, a 90nm gold electrode is deposited on the ZTO fiber surface obtained in step (4) to serve as the source and drain of the synaptic device.

[0045] (6) In step (5), a 200 μm thick PVDF-HFP / [EMIM][TFSI] ionomer glue is attached to the fiber surface of the sample as the gate of the synaptic device, and finally ZTO fiber-based synaptic device is fabricated.

[0046] (7) Use a semiconductor analyzer to test the electrical performance of the synaptic device in step (6).

[0047] By optimizing experimental parameters, ZTO fiber-based synaptic devices with tunable electrical properties were successfully fabricated. Figure 1 It is the long serpentine printing trajectory of ZTO fibers, where 'a' represents the length of the printed fiber and 'b' represents the spacing between adjacent fibers. By setting the distance of segment 'b', the spacing between adjacent fibers can be precisely controlled. The fibers printed along the trajectory are arranged in an orderly manner, and within the same range, the smaller the spacing, the more fibers there are. That is, adjusting the distance of segment 'b' can precisely control the number of printed fibers. Figure 2 Images of ZTO fiber optic microscopy at different spacings are shown. Figure 2 (a) and Figure 2 (b) It can be seen that the spacing between adjacent fibers is approximately 50 μm for sample A and 100 μm for sample B, which is consistent with the printing settings. Furthermore, the number of fibers in sample A is greater than that in sample B within the same area. Figure 3 The images are scanning electron microscope images of ZTO fibers prepared by the traditional electrospinning method, published in the American academic journal IEEE Electron Device Letters, Volume 40, 2019, pages 1776-1779. As can be seen from the images, the ZTO fibers prepared by this method are randomly distributed and cannot be arranged in an orderly manner, and the spacing between adjacent ZTO fibers cannot be precisely controlled. By comparison, it can be seen that the ZTO fibers prepared by this invention have the advantages of orderly arrangement and precise control of the spacing between adjacent fibers.

[0048] Figure 4 A schematic diagram of a ZTO fiber-based synaptic device is shown, using Si / SiO2 as a substrate, including a gold electrode, an ion-adhesive gate, and a ZTO fiber channel layer. The electrical performance of the ZTO fiber-based synaptic device prepared in Example 1 was tested using a Keithley 4200A-SCS semiconductor analyzer. Figure 5 (a) and Figure 5 (b) The excitatory postsynaptic current (EPSC) of ZTO fiber-based synaptic devices prepared using samples A and B are shown respectively. With a gate voltage of 3V, a drain voltage of 0.1V, and a pulse duration of 50ms, the peak EPSC values ​​(defined as the maximum EPSC minus the resting current value) of samples A and B are 2.43μA and 1.16μA, respectively, demonstrating that the electrical performance of the synaptic device can be tuned by controlling the number of control fibers. Figure 6 (a) and Figure 6 (b) The double-pulse facilitation (PPF) of ZTO fiber-based synaptic devices prepared using sample A and sample B is shown at a gate voltage of 3V, a drain voltage of 0.1V, a pulse duration of 50ms, and a pulse interval of 50ms. It can be seen that the double-pulse facilitation phenomenon was measured in both samples with different fiber numbers. That is, when the second stimulus is applied, the subsequent current is significantly stronger than the current generated by the first stimulus. However, the EPSC peak value of sample B (3.67μA) with more fiber number is higher than that of sample A (1.91μA) during the second consecutive stimulus. Figure 7 (a) and Figure 7 (b) Pulse frequency-dependent plasticity (SFDP) test plots of ZTO fiber-based synaptic devices prepared using samples A and B are shown respectively, at a gate voltage of 3V and a drain voltage of 0.1V. As the pulse frequency gradually increases (1.8Hz, 3.3Hz, 5.0Hz, and 6.7Hz), the postsynaptic current of both samples gradually increases, but the synaptic device with more fibers has a larger current value. The above data demonstrate that the ZTO fiber-based synaptic device prepared in this invention can simulate the function of biological synapses, and the electrical performance of the synaptic device can be controlled by selecting the number of fibers.

[0049] Example 2

[0050] (1) The Si / SiO2 substrate to be used was ultrasonically cleaned for 15 minutes in sequence with deionized water, isopropanol, acetone and anhydrous ethanol, and then the substrate surface was dried with nitrogen.

[0051] (2) Prepare a mixed solvent by mixing N,N-dimethylformamide and anhydrous ethanol in a mass ratio of 1.5:1; dissolve reagents with a mass ratio of polyvinylpyrrolidone:(zinc nitrate hydrate + stannous chloride dihydrate) = 1:2 and a molar ratio of zinc nitrate hydrate:stannous chloride dihydrate = 1:1 in the mixed solvent, and stir at 25°C for 12 hours using a magnetic stirrer to prepare the precursor solution required for printing; the mass concentration of polyvinylpyrrolidone in the precursor solution is 12%.

[0052] (3) Using a Huawico electrohydrodynamic printer, the precursor solution prepared in step (2) was printed into ZTO fibers. During printing, a high voltage of 1.0 kV was applied to the syringe needle, the distance from the syringe needle to the substrate was set to 3.3 mm, the liquid flow rate of the syringe was set to 60 nL / min, the moving speed of the substrate was set to 150 mm / s, the substrate temperature was set to 42 °C, the printing length was set to 20 cm, and the spacing between adjacent fibers was set to sample A = 20 μm and sample B = 1000 μm, respectively.

[0053] (4) The fiber obtained by printing in step (3) is calcined at 600°C in air for 60 minutes to finally obtain ZTO fiber;

[0054] (5) Using a photomask, a 120nm titanium / gold electrode is deposited on the ZTO fiber surface obtained in step (4) as the source and drain of the synaptic device.

[0055] (6) In step (5), a 200 μm thick PVDF-HFP / [EMIM][TFSI] ionomer glue is attached to the fiber surface of the sample as the gate of the synaptic device, and finally ZTO fiber-based synaptic device is fabricated.

[0056] (7) Use a semiconductor analyzer to test the electrical performance of the synaptic device in step (6).

[0057] Example 3

[0058] (1) The Si / SiO2 substrate to be used was ultrasonically cleaned for 30 minutes in sequence with deionized water, isopropanol, acetone and anhydrous ethanol, and then the substrate surface was dried with nitrogen.

[0059] (2) Prepare a mixed solvent by mixing N,N-dimethylformamide and anhydrous ethanol in a mass ratio of 2:1; dissolve reagents with a mass ratio of polyvinylpyrrolidone:(zinc nitrate hydrate + stannous chloride dihydrate) = 1:1.5 and a molar ratio of zinc nitrate hydrate:stannous chloride dihydrate = 3:7 in the mixed solvent, and stir at 25°C for 12 hours using a magnetic stirrer to prepare the precursor solution required for printing; the mass concentration of polyvinylpyrrolidone in the precursor solution is 9%.

[0060] (3) Using a Huawico electrohydrodynamic printer, the precursor solution prepared in step (2) was printed into ZTO fibers. During printing, a high voltage of 1.1kV was applied to the syringe needle, the distance from the syringe needle to the substrate was set to 3.7mm, the liquid flow rate of the syringe was set to 30nL / min, the moving speed of the substrate was set to 450mm / s, the substrate temperature was set to 43℃, the printing length was set to 20cm, and the spacing between adjacent fibers was set to sample A = 80μm and sample B = 400μm, respectively.

[0061] (4) The fiber obtained from the printing in step (3) is calcined in air at 450°C for 120 minutes to finally obtain ZTO fiber.

[0062] (5) Using a photomask, a 90nm gold electrode is deposited on the ZTO fiber surface obtained in step (4) to serve as the source and drain of the synaptic device.

[0063] (6) In step (5), chitosan ionomer glue is attached to the fiber surface of the sample as the gate of the synaptic device, and finally ZTO fiber-based synaptic device is made.

[0064] (7) Use a semiconductor analyzer to test the electrical performance of the synaptic device in step (6).

[0065] This invention utilizes a Huawico electro-hydraulic printer to prepare ZTO semiconductor fibers that can be arranged in an orderly manner. During the preparation process, the spacing between adjacent ZTO fibers is precisely controlled by setting printing parameters according to electrical performance requirements. This allows for precise control of the number of ZTO fibers within the same area, further enabling the fabrication of synaptic devices and precise regulation of their electrical properties. Using the control method of this invention, when designing and fabricating integrated circuits containing synaptic devices, the spacing and number of fibers can be customized according to the operational needs of the circuit system. Synaptic devices that meet the electrical requirements of integrated circuits can be fabricated in one step, simplifying the problem of matching the electrical performance of synaptic devices with that of the circuit system. This provides an effective method for device design and fabrication in the fields of neuromorphic electronics and brain-like computing, promoting the development of integrated circuits containing synaptic devices.

[0066] Matters not covered in this invention are common knowledge.

Claims

1. A method for fabricating a ZTO fiber-based synaptic device with tunable electrical properties, characterized by comprising the following steps: (1) Clean the substrate to be used with deionized water, isopropanol, acetone and anhydrous ethanol in sequence for 15-30 minutes, and then dry the substrate surface with nitrogen. (2) Add polyvinylpyrrolidone, zinc nitrate hydrate and stannous chloride dihydrate to a mixed solvent and stir magnetically at 20-70°C for 0.5-24 hours to obtain a precursor solution; in, The mixed solvent is a mixture of N,N-dimethylformamide and anhydrous ethanol in a mass ratio of 1 to 6:1, with a mass ratio of polyvinylpyrrolidone:(zinc nitrate hydrate + stannous chloride dihydrate) of 1:1 to 4 and a molar ratio of zinc nitrate hydrate:stannous chloride dihydrate of 7:3 to 3:

7. The mass concentration of polyvinylpyrrolidone in the precursor solution is 5% to 14%. (3) Using an electrohydrodynamic printer, the precursor solution prepared in step (2) is printed as ZTO fibers on the substrate; The syringe needle is subjected to a high voltage of 0.5 to 4.5 kV, the distance between the syringe needle and the substrate is 0.5 to 20 mm, the liquid flow rate of the syringe is 1 to 250 nL / min, the substrate moving speed is 50 to 1000 mm / s, the substrate temperature is 40 to 80 ℃, the printing length is 0.01 to 20 cm, and the spacing between adjacent fibers is 5 to 1000 μm. (4) Calcine the ZTO fiber from step (3) in air at 300-700°C for 30-300 minutes, and remove it after the temperature drops to room temperature; (5) Using a mask template, electrodes are deposited at both ends of the ZTO fiber surface obtained in step (4) to serve as the source and drain of the synaptic device; (6) In step (5), ionomer glue is attached to the fiber surface as the gate of the synaptic device, and finally a ZTO fiber-based synaptic device with controllable fiber quantity is made.

2. The method for preparing the ZTO fiber-based synaptic device with adjustable electrical properties as described in claim 1, characterized in that the method for adjusting the electrical properties of the ZTO fiber-based synaptic device is such that when the spacing between the ZTO fibers decreases by a multiple, the electrical properties tend to increase by a corresponding multiple, thereby increasing the peak EPSC of the obtained ZTO fiber-based synaptic device by a corresponding multiple.

3. The method for preparing the electrically tunable ZTO fiber-based synaptic device as described in claim 2 is characterized in that: when the nanofiber spacing decreases by half from 100 μm to 50 μm, the electrical performance increases by half accordingly, and the resulting ZTO fiber-based synaptic device increases the EPSC peak value under a single pulse stimulation from 1.16 μA to 2.43 μA.

4. The method for fabricating the electrically tunable ZTO fiber-based synaptic device as described in claim 1, characterized in that: The substrate in step (1) is Si / SiO2, Al2O3, or glass; In step (5), metal electrodes with a thickness of 60-200 nm and spaced apart are deposited on the surface of ZTO fiber using a photomask as the source and drain electrodes. The metal is gold, silver, aluminum, or titanium / gold. In step (6), the ionomer is chitosan, PVA, or [EMIM][TFSI], with a thickness of 0.05 to 500 μm.

Images