Synaptic transistor based on mxene inkjet printing and preparation method thereof
By using MXene inkjet printing technology, the problems of poor electrical performance and high cost of MXene synaptic transistors have been solved, enabling high-precision printing and biological behavior simulation, simplifying the process and reducing the manufacturing cost.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- UNIV OF SCI & TECH BEIJING
- Filing Date
- 2024-10-29
- Publication Date
- 2026-06-26
AI Technical Summary
Existing inkjet printing technology for MXene synaptic transistors is limited by poor electrical performance, thick thin film layers and large pattern sizes, and the use of high-boiling-point solvents leads to device performance degradation and high material costs.
A method for fabricating synaptic transistors using MXene inkjet printing is employed, which includes substrate cleaning, photolithographic patterning, electrode deposition, wet chemical etching and mechanical stripping, preparation of MXene dispersion by liquid-phase cascade centrifugation, hydrophilic treatment and inkjet printing of thin films, and the construction of transistors by combining a solid electrolyte dielectric layer.
It enables high-precision printing of thin continuous patterns, reduces fabrication costs, enhances the non-volatility and bio-behavioral simulation performance of devices, and simplifies the process flow.
Smart Images
Figure CN119451524B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of printed biomimetic electronic devices, specifically to a synaptic transistor based on MXene ink membrane printing and its fabrication method. Background Technology
[0002] Artificial intelligence (AI) is rapidly becoming widespread and transforming how we process everyday information. This rapid development of AI technologies is driven by innovative algorithms for big data processing (software level) and high-performance semiconductor chips (hardware level). However, computing architectures based on traditional semiconductor devices are inefficient when performing massive tasks, primarily because storage and computation are separated—a phenomenon known as the von Neumann bottleneck. Inspired by the structure of the human brain, neuromorphic computing has been developed to achieve parallel computation by simulating the synaptic behavior of biological neural networks. In devices that implement artificial synaptic functions, electrolyte-gated transistors provide a flexible approach to synaptic simulation. The gate electrode can be considered a presynaptic neuron, the channel between the source and drain electrodes can be considered a postsynaptic neuron, and the channel's conductance can be used to simulate synaptic weights.
[0003] Among channel materials used in electrolyte-gated synaptic transistors, two-dimensional MXene materials composed of transition metal carbides, nitrides, or carbonitrides show great potential in neuromorphic computing due to their excellent electrical and mechanical properties, hydrophilicity, and tunable surface end groups. However, the fabrication of most MXene transistors relies on expensive and time-consuming micro / nano fabrication techniques such as photolithography and etching, and the use of organic reagents such as photoresists can also affect the performance of MXene synaptic transistors. Printed electronics technology is gradually demonstrating its advantages due to its economy, adaptability, and compatibility with various substrates and different shape and size. Printable MXene synaptic transistors can improve performance, reduce power consumption, and enhance device characteristics (such as high sensitivity, easy customization of functions, and flexibility), showing great potential in the neuromorphic field.
[0004] Currently, inkjet-printed MXene synaptic crystals are still limited by poor electrical performance, thick thin film layers, and large pattern sizes (millimeter level), mainly due to the difficulty in printing thin, continuous patterns with high precision.
[0005] Most MXene inks use water as a solvent, but the surface tension mismatch between 2D materials and solvents, as well as the imbalance of minute forces between them, often makes it difficult to achieve a stable and uniform printing process. MXene inks that use high-boiling-point solvents, such as N,N-dimethylamide (DMF) and N-methyl-2-pyrrolidone (NMP), are often supplemented with other surfactants, which can lead to degraded device performance, high material costs, and high toxicity, making them unsuitable for large-scale applications. Summary of the Invention
[0006] This invention proposes a method for fabricating synaptic transistors based on MXene inkjet printing, which includes the following steps:
[0007] S1: Select a substrate and clean the substrate;
[0008] S2: The gate, source and drain on the substrate are patterned using photolithography.
[0009] S3: Deposit the gate, source, and drain on the substrate;
[0010] S4: Few-layer MXene was obtained by wet chemical etching combined with mechanical exfoliation of MAX phase material;
[0011] S5: Obtain an MXene dispersion with a certain flake size distribution by liquid phase cascade centrifugation;
[0012] S6: Prepare MXene ink using the MXene dispersion;
[0013] S7: Perform hydrophilic treatment on the surface of the substrate, set the MXene film printing parameters, and print the MXene film at the channel position using the MXene ink;
[0014] S8: Prepare an electrolyte solution and drop-cast a dielectric layer on the MXene channel layer, the gate, and the exposed substrate. The dielectric layer covers the channel layer and connects to the gate to construct an MXene synaptic transistor.
[0015] A further provision of the present invention is that the substrate in step S1 is selected as an insulating rigid material.
[0016] A further provision of the present invention is that the substrate is selected from any one of silicon oxide wafers, glass, ceramics, and sapphire substrates.
[0017] A further provision of the present invention is that the substrate is sequentially cleaned with acetone, isopropanol, and deionized water, and then dried using nitrogen gas.
[0018] A further setting of the present invention is that the deposition thickness of each electrode in step S3 is 30-60 nm.
[0019] A further feature of the present invention is that the MXene material in step S4 is Ti3C2T. X V2CT X Nb2CT X Ti3CNT X One of them; the ratio of ethanol to water in the MXene ink is 1:9, 2:8, or 3:7.
[0020] A further provision of the present invention is that the printing parameters set in step S7 include amplitude and speed, wherein the amplitude is 0.5-5V and the speed is 0.01-1mms. -1 The thickness of the printed MXene thin film pattern is 5-15nm.
[0021] A further configuration of the present invention is as follows: in step S8, the dielectric layer is Nafion 117 as a proton-donating layer, or PEO / LiTFSI as a lithium-ion-donating layer, wherein the mass ratio of PEO to LiTFSI is 2-5:1.
[0022] This invention also proposes a synaptic transistor based on MXene inkjet printing, which is fabricated using the method described in the figure.
[0023] The beneficial effects of this invention are as follows:
[0024] The use of inkjet printing to fabricate synaptic transistors with MXene as the channel layer avoids the impact of traditional micro-nano fabrication processes such as photolithography and etching on MXene materials, and greatly simplifies the process flow and significantly reduces the fabrication cost. Attached Figure Description
[0025] Figure 1 A schematic diagram of the structure of the MXene synaptic transistor prepared according to the present invention is shown.
[0026] Figure 2 The contact angle between the MXene ink prepared according to the present invention and the silicon oxide wafer is shown.
[0027] Figure 3 The diagram shows a pattern printed on a silicon oxide wafer using the MXene ink prepared according to the present invention.
[0028] Figure 4 An optical mirror image of the MXene synaptic transistor constructed according to the present invention is shown.
[0029] Figure 5 The transfer characteristic curve of the MXene synaptic transistor is shown.
[0030] Figure 6 The response and decay behavior of the excitatory postsynaptic current in the MXene synaptic transistor are shown.
[0031] Figure 7 The response and decay behavior of the excitatory synaptic currents of the MXene synaptic transistor, triggered by a pulse sequence with increasing amplitude, are shown. Detailed Implementation
[0032] Those skilled in the art can refer to the content of this document and appropriately improve the process parameters to achieve the desired results. It should be particularly noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included in this invention. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art can make modifications or appropriate alterations and combinations to the methods and applications described herein without departing from the content, spirit, and scope of this invention to implement and apply the technology of this invention.
[0033] Example 1
[0034] This invention proposes a method for fabricating synaptic transistors based on MXene ink membrane printing, comprising the following steps:
[0035] S1: Select a substrate and clean and dry it;
[0036] S2: The gate, source and drain on the substrate are patterned using photolithography.
[0037] S3: Deposit the gate, source, and drain on the substrate;
[0038] S4: Few-layer MXene was obtained by wet chemical etching combined with mechanical exfoliation of MAX phase material;
[0039] S5: Obtain an MXene dispersion with a certain flake size distribution by liquid phase cascade centrifugation;
[0040] S6: Preparation of MXene ink using MXene dispersion;
[0041] S7: Perform hydrophilic treatment on the surface of the substrate, set the MXene film printing parameters, and print the MXene film with MXene ink at the channel position;
[0042] S8: Prepare an electrolyte solution, and drop-cast a dielectric layer on the MXene channel layer, gate, and exposed substrate. The dielectric layer covers the channel layer and connects to the gate to construct an MXene synaptic transistor.
[0043] In step S1, the substrate is selected from an insulating rigid material, that is, any one of silicon oxide wafer, glass, ceramic, or sapphire substrate.
[0044] The selected substrate needs to be cleaned sequentially with acetone, isopropanol and deionized water, and then dried with nitrogen gas after cleaning.
[0045] In step S3, the deposition method can be either DC magnetron sputtering or electron beam evaporation, and the material of the deposition electrode is Au or Pt, with a deposition thickness of 30-60 nm for each electrode. It should be noted that a 5 nm Cr needs to be deposited before the deposition electrode.
[0046] In step S4, the MXene material is Ti3C2T. X V2CT X Nb2CT X 、T i3CNT X Any of the following. In step S6, the ratio of ethanol to water in the MXene ink is 1:9, 2:8, or 3:7.
[0047] In step S7, the hydrophilic treatment method can be either ultraviolet ozone treatment or plasma treatment. During the printing process, the printing device's needle needs to be in direct contact with the substrate surface. The spraying mode is manually activated by applying voltage to the piezoelectric element connected to the micropipette. The set printing parameters include amplitude and speed, with the amplitude being 0.5-5V and the speed being 0.01-1mms. -1 The thickness of the printed MXene thin film pattern is 5-15 nm.
[0048] In step S8, the dielectric layer is either Nafion 117 as the proton-donating layer or PEO / Li TFSI as the lithium-ion-donating layer, wherein the mass ratio of PEO to LiTFSI is 2.5-5:1.
[0049] Example 2
[0050] refer to Figure 1 In this embodiment, the MXene synaptic transistor is fabricated using the fabrication method disclosed in Example 1, based on Ti3C2T. X The MXene synaptic transistor has a side-gate structure, including a substrate, gate (G), source (S), drain (D), MXene channel layer, and solid electrolyte dielectric layer. The channel layer is printed using inkjet printing with Ti3C2T. X It is made of MXene ink, and the dielectric layer is made by drop-casting an electrolyte solution. The specific steps are as follows:
[0051] S1: Select a silicon oxide wafer as the substrate. The 2×2cm silicon oxide wafer is ultrasonically cleaned in acetone, isopropanol and deionized water for 5 minutes in sequence to remove contaminants on the substrate surface, and then dried with nitrogen.
[0052] S2: Using photolithography, the gate, source, and drain are patterned on the substrate through steps such as spin coating of photoresist negative, pre-baking, ultraviolet exposure, post-baking, development, and fixing. The channel spacing between the source and drain is 5μm and the length is 100μm.
[0053] S3: Cr and Au metal electrodes are deposited on the substrate by electron beam evaporation deposition, with thicknesses of 5 nm and 50 nm respectively.
[0054] S4: Preparation of few-layer Ti3C2T X :
[0055] S4-1: Weigh 1.56g LiF and add it to 20ml of 9M HCl. Stir in a polytetrafluoroethylene beaker for 5 minutes.
[0056] S4-2: Slowly add 1g Ti3AlC2 powder to the solution in step S4-1 above, place the polytetrafluoroethylene beaker in an oil bath at 40°C, and stir continuously for 30 hours.
[0057] S4-3: After the reaction is complete, wash the reaction mixture 5-6 times with deionized water (centrifuged at 5000 rpm for 5 minutes) until the pH reaches 6, finally obtaining a multilayer Ti3C2T precipitate with obvious swelling at the bottom. X ;
[0058] S4-4: Add the precipitate from step S4-3 to 30ml of deionized water, shake manually for 10 minutes, then pour into a gas washing bottle. Connect the long end to an inert gas and sonicate for 50 minutes under aeration and flowing water conditions. At this point, mechanical exfoliation is complete, yielding Ti3C2T. X Dispersion.
[0059] S5: Preparation of few-layer Ti3C2T with different flake size distributions X Dispersion:
[0060] S5-1: Ti3C2T after ultrasound completion X Centrifuge the dispersion at 1000 rpm for 30 min, transfer the supernatant to a new centrifuge tube, and continue centrifuging at 4000 rpm for 30 min. The sediment is retained and recorded as 1-4 krpm.
[0061] S5-2: Continue centrifuging the supernatant at 8000 rpm for 30 min, retain the sediment and record it as 4-8 krpm;
[0062] S5-3: The last supernatant was centrifuged at 12000 rpm for 30 min, and the precipitate was retained and recorded as 8-12 krpm;
[0063] S5-4: After the above cascade centrifugation process, three types of Ti3C2T can be obtained: 1-4k, 4-8k, and 8-12krpm. X After precipitation, 10 mL of deionized water was added to each, and the mixture was shaken by hand for 10 min to redisperse the precipitate in the water. This yielded Ti3C2T with three different size distributions. X Dispersion.
[0064] S6: Preparation of Ti3C2T X Ink, Ti3C2T XA solution with a solute concentration of 1 mg / ml and anhydrous ethanol:deionized water in a ratio of 1:9 was prepared by hand-shaking to disperse the solution evenly and set aside for later use.
[0065] S7: Inkjet Printing
[0066] S7-1: Place the substrate in the ultraviolet ozone generator and irradiate it with ultraviolet lamps for 20 minutes;
[0067] S7-2: The needle diameter used is 20μm. The pre-designed printing pattern program is invoked, and the printing parameters are adjusted: nozzle amplitude is 1.5V, nozzle frequency is 450kHz, and speed is 0.1mm / s. -1 The printed MXene film area is 20μm×100μm. The printed MXene film is heat-treated at 90℃ for 30 minutes in a vacuum drying oven to enhance the adhesion between the substrate and MXene, and at the same time promote the evaporation of solvent.
[0068] S8: Constructing Ti3C2T X Synaptic transistor:
[0069] S8-1: Weigh 250g of polyethylene oxide and 100g of lithium bis(fluorosulfonyl)imide salt, add them to 10ml of anhydrous acetonitrile, and stir overnight at 60℃ until the solution is clear;
[0070] S8-2: Use a pipette to drop 2 μL of electrolyte solution onto the channel layer, gate, and exposed substrate. The dielectric layer covers the channel layer and connects to the gate.
[0071] S8-3: Place the device in a vacuum drying oven and heat it at 90°C for 20 minutes to remove unvolatile acetonitrile.
[0072] refer to Figure 2 It can be seen that the prepared Ti3C2T X The contact angle of the ink on the silicon oxide wafer is 45°, reference. Figure 3 The pattern continuously printed with this ink under the parameters of step S7 shows that the pattern is stable and uniform, without coffee ring cloning or Rayleigh instability effects. (Reference) Figure 4 For the prepared Ti3C2T X Optical mirror image of a synaptic transistor.
[0073] refer to Figure 5 To test the transfer characteristics of the synthesized synaptic transistor using a semiconductor parameter analyzer, a small DC voltage V is applied between the source and drain. DS =100mV, making the gate voltage V G Scan the range from 3V to -3V and then back to 3V once, setting different scan speeds, and record the channel current I. D As you can see, VG At 0V, there is a significant hysteresis phenomenon, indicating that the channel conductivity has undergone a non-volatile change under electrochemical doping, which is crucial for the simulation of synaptic performance.
[0074] Example 3
[0075] This embodiment uses the fabrication method disclosed in Example 1 to fabricate MXene synaptic transistors based on V2CT. X The MXene synaptic transistor has a side-gate structure, including a substrate, gate (G), source (S), drain (D), MXene channel layer, and solid electrolyte dielectric layer. The channel layer is printed using inkjet printing of V2CT. X It is made of MXene ink, and the dielectric layer is made by drop-casting an electrolyte solution. The specific steps are as follows:
[0076] S1: Select a glass slide as the substrate. The 2×2cm glass slide is ultrasonically cleaned in acetone, isopropanol and deionized water for 5 minutes in sequence to remove contaminants on the substrate surface, and then dried with nitrogen.
[0077] S2: Using photolithography, the gate, source, and drain are patterned on the substrate through steps such as spin coating of photoresist negative, pre-baking, ultraviolet exposure, post-baking, development, and fixing. The channel spacing between the source and drain is 5μm and the length is 100μm.
[0078] S3: Cr and Au metal electrodes are deposited on the substrate by DC magnetron sputtering, with thicknesses of 5 nm and 60 nm respectively.
[0079] S4: Preparation of few-slice V2CT X :
[0080] S4-1: Slowly add 2g of V2A l C powder to 40ml of HF with a mass fraction of 49%, place the polytetrafluoroethylene beaker in an oil bath at 40℃, and stir continuously for 72 hours;
[0081] S4-2: After the reaction is complete, wash the reaction mixture 5-6 times with deionized water (centrifuged at 8000 rpm for 5 minutes) until the pH reaches 6. The final precipitate is a multilayer V2CT. X ;
[0082] S4-3: Add 1g of the precipitate obtained in step S4-2 to 20ml of 5wt% tetrabutylammonium hydroxide solution and stir at 25℃ for 6 hours;
[0083] S4-4: After stirring, transfer the solution to a certain amount of deionized water, centrifuge at 5000 rpm for 5 minutes, discard the supernatant, disperse the precipitate in the deionized water and shake by hand for 5 minutes. Repeat the centrifugation and shaking steps until the color of the supernatant becomes darker.
[0084] S5: Preparing few-slice V2CT with different slice size distributions X Dispersion:
[0085] S5-1: V2CT after ultrasound completion X Centrifuge the dispersion at 1000 rpm for 30 min, transfer the supernatant to a new centrifuge tube, and continue centrifuging at 4000 rpm for 30 min. The sediment is retained and recorded as 1-4 krpm.
[0086] S5-2: Continue centrifuging the supernatant at 8000 rpm for 30 min, retain the sediment and record it as 4-8 krpm;
[0087] S5-3: The last supernatant was centrifuged at 12000 rpm for 30 min, and the precipitate was retained and recorded as 8-12 krpm;
[0088] S5-4: After the above cascade centrifugation process, three V2CT values can be obtained: 1-4k, 4-8k, and 8-12k rpm. X After precipitation, 10 mL of deionized water was added to each, and the mixture was shaken by hand for 10 minutes to redisperse the precipitate in the water. This yielded V2CT with three size distributions. X Dispersion.
[0089] S6: Preparing V2CT X Ink, V2CT X A solution with a solute concentration of 1 mg / ml is prepared by mixing anhydrous ethanol and deionized water in a ratio of 2:8. The solution is then shaken by hand to disperse it evenly and set aside for later use.
[0090] S7: Inkjet Printing
[0091] S7-1: Place the substrate in a plasma etching machine and treat it with oxygen plasma for 3 minutes;
[0092] S7-2: The needle diameter used is 20μm. The pre-designed printing pattern program is invoked, and the printing parameters are adjusted: nozzle amplitude is 2V, nozzle frequency is 450kHz, and speed is 0.3mm / s. -1 The printed MXene film area is 20μm×100μm. The printed MXene film is heat-treated at 90℃ for 30 minutes in a vacuum drying oven to enhance the adhesion between the substrate and MXene, and at the same time promote the evaporation of solvent.
[0093] S8: Constructing V2CT XSynaptic transistor:
[0094] S8-1: Use a pipette to drop 2 μL of Nafion 117 solution onto the channel layer, gate, and exposed substrate. The dielectric layer covers the channel layer and connects to the gate.
[0095] S8-2: Place the device in a vacuum drying oven and heat it at 90°C for 20 minutes to remove any unevaporated solvent.
[0096] Replace the channel material with V2CT X The electrolyte solution was replaced with Nafion 117 to provide protons for the channel layer. The V2CT fabricated above was analyzed using a semiconductor parameter analyzer. X MXene synaptic transistors are subjected to pulse testing. (Reference) Figure 6 A pulse voltage of 3V was applied to the gate with a pulse width of 100ms, and the voltage between the source and drain was set to 100mV. The excitatory postsynaptic current reached its maximum value at the moment the pulse ended, and then gradually decreased, but did not return to its initial value, exhibiting long-term memory (10). 2 s) characteristics. (See reference) Figure 7 When a series of linearly increasing pulses (0.5-3V) are applied to the gate, the current response increases with the increase of the pulse amplitude. This electrical property is similar to the signal behavior in biological excitatory synapses.
[0097] Example 4
[0098] refer to Figure 1 In this embodiment, the MXene synaptic transistor is fabricated using the method disclosed in Example 1, based on Ti3CNT. X The MXene synaptic transistor has a side-gate structure, including a substrate, gate (G), source (S), drain (D), MXene channel layer, and solid electrolyte dielectric layer. The channel layer is printed using inkjet printing with Ti3CNT. X It is made of MXene ink, and the dielectric layer is made by drop-casting an electrolyte solution. The specific steps are as follows:
[0099] S1: Using a sapphire substrate as the substrate, the 2×2cm sapphire substrate is ultrasonically cleaned for 5 minutes in acetone, isopropanol and deionized water in sequence to remove contaminants on the substrate surface, and then dried with nitrogen.
[0100] S2: Using photolithography, the gate, source, and drain are patterned on the substrate through steps such as spin coating of photoresist negative, pre-baking, ultraviolet exposure, post-baking, development, and fixing. The channel spacing between the source and drain is 5μm and the length is 100μm.
[0101] S3: Cr and Au metal electrodes are deposited on the substrate by electron beam evaporation deposition, with thicknesses of 5 nm and 60 nm respectively.
[0102] S4: Preparation of few-layer Ti3CNTs X :
[0103] S4-1: Weigh 1.6g LiF and add it to 20ml of 9M HCl. Stir in a polytetrafluoroethylene beaker for 15 minutes.
[0104] S4-2: Slowly add 1g Ti3AlCN powder to the solution in step S4-1 above, place the polytetrafluoroethylene beaker in an oil bath at 35°C, and stir continuously for 18 hours.
[0105] S4-3: After the reaction is complete, wash the reaction mixture 7-8 times with deionized water (centrifuged at 3500 rpm for 1 minute) until the pH is 6, then filter under vacuum.
[0106] S4-4: Add the precipitate after vacuum filtration back into the centrifuge tube and continue centrifuging until a viscous precipitate appears and the upper layer turns black. Then stop centrifugation and discard the upper layer.
[0107] S4-5: Add the precipitate from step S4-4 to 30ml of deionized water, shake manually for 20 minutes, then pour into a gas washing bottle. Connect the long end to an inert gas and sonicate for 50 minutes under aeration and flowing water conditions. At this point, mechanical exfoliation is complete, and Ti3CNT is obtained. X Dispersion.
[0108] S5: Preparation of few-layer Ti3CNTs with different flake size distributions X Dispersion:
[0109] S5-1: Ti3CNTs after ultrasound treatment X Centrifuge the dispersion at 1000 rpm for 30 min, transfer the supernatant to a new centrifuge tube, and continue centrifuging at 4000 rpm for 30 min. The sediment is retained and recorded as 1-4 krpm.
[0110] S5-2: Continue centrifuging the supernatant at 8000 rpm for 30 min, retain the sediment and record it as 4-8 krpm;
[0111] S5-3: The last supernatant was centrifuged at 12000 rpm for 30 min, and the precipitate was retained and recorded as 8-12 krpm;
[0112] S5-4: After the above cascade centrifugation process, three types of Ti3CNT can be obtained at 1-4k, 4-8k, and 8-12krpm. XAfter precipitation, 10 mL of deionized water was added to each, and the mixture was shaken by hand for 10 min to redisperse the precipitate in the water. This yielded Ti3CNTs with three size distributions. X Dispersion.
[0113] S6: Preparation of Ti3CNT X Ink, Ti3CNT X A solution with a solute concentration of 1 mg / ml is prepared by mixing anhydrous ethanol and deionized water in a ratio of 3:7. The solution is then shaken by hand to disperse it evenly and set aside for later use.
[0114] S7: Inkjet Printing
[0115] S7-1: Place the substrate in the ultraviolet ozone generator and irradiate it with ultraviolet lamps for 20 minutes;
[0116] S7-2: The needle diameter used is 20μm. The pre-designed printing pattern program is invoked, and the printing parameters are adjusted: nozzle amplitude is 0.5V, nozzle frequency is 450kHz, and speed is 0.5mm / s. -1 The printed MXene film area is 20μm×100μm. The printed MXene film is heat-treated at 90℃ for 30 minutes in a vacuum drying oven to enhance the adhesion between the substrate and MXene, and at the same time promote the evaporation of solvent.
[0117] S8: Constructing Ti3CNT X Synaptic transistor:
[0118] S8-1: Weigh 250g of polyethylene oxide and 100g of lithium bis(fluorosulfonyl)imide salt, add them to 10ml of anhydrous acetonitrile, and stir overnight at 60℃ until the solution is clear;
[0119] S8-2: Use a pipette to drop 2 μL of electrolyte solution onto the channel layer, gate, and exposed substrate. The dielectric layer covers the channel layer and connects to the gate.
[0120] S8-3: Place the device in a vacuum drying oven and heat it at 90°C for 20 minutes to remove unvolatile acetonitrile.
[0121] Example 5
[0122] This embodiment uses the fabrication method disclosed in Example 1 to fabricate MXene synaptic transistors based on N2CT. X The MXene synaptic transistor has a side-gate structure, including a substrate, gate (G), source (S), drain (D), MXene channel layer, and solid electrolyte dielectric layer. The channel layer is printed using inkjet printing of N2CT. X It is made of MXene ink, and the dielectric layer is made by drop-casting an electrolyte solution. The specific steps are as follows:
[0123] S1: Select a silicon oxide wafer as the substrate. The 2×2cm silicon oxide wafer is ultrasonically cleaned in acetone, isopropanol and deionized water for 5 minutes in sequence to remove contaminants on the substrate surface, and then dried with nitrogen.
[0124] S2: Using photolithography, the gate, source, and drain are patterned on the substrate through steps such as spin coating of photoresist negative, pre-baking, ultraviolet exposure, post-baking, development, and fixing. The channel spacing between the source and drain is 5μm and the length is 100μm.
[0125] S3: Cr and Pt metal electrodes are deposited on the substrate by DC magnetron sputtering, with thicknesses of 5 nm and 50 nm respectively.
[0126] S4: Preparation of few-slice N2CT X :
[0127] S4-1Nb2Al C: Slowly add 1g of Nb2Al C powder to 20ml of HF with a mass fraction of 49%, place the polytetrafluoroethylene beaker in an oil bath at 60℃, and stir continuously for 90 hours.
[0128] S4-2: After the reaction is complete, wash the reaction mixture 5-6 times with deionized water (centrifuged at 5000 rpm for 5 minutes) until the pH reaches 6. The final precipitate is a multilayer N2CT. X ;
[0129] S4-3: Add 0.5g of the precipitate obtained in step S4-2 to 10ml of 5wt% tetra-n-butylammonium hydroxide solution and stir at 25°C for 8 hours;
[0130] S4-4: After stirring, transfer the solution to a certain amount of deionized water, centrifuge at 5000 rpm for 5 minutes, discard the supernatant, disperse the precipitate in the deionized water and shake by hand for 5 minutes. Repeat the centrifugation and shaking steps until the color of the supernatant darkens.
[0131] S5: Preparation of few-slice N2CT with different slice size distributions X Dispersion:
[0132] S5-1: N2CT after ultrasound completion X Centrifuge the dispersion at 1000 rpm for 30 min, transfer the supernatant to a new centrifuge tube, and continue centrifuging at 4000 rpm for 30 min. The sediment is retained and recorded as 1-4 krpm.
[0133] S5-2: Continue centrifuging the supernatant at 8000 rpm for 30 min, retain the sediment and record it as 4-8 krpm;
[0134] S5-3: The last supernatant was centrifuged at 12000 rpm for 30 min, and the precipitate was retained and recorded as 8-12 krpm;
[0135] S5-4: After the above cascade centrifugation process, three types of N2CT can be obtained: 1-4k, 4-8k, and 8-12krpm. X After precipitation, 10 mL of deionized water was added to each, and the mixture was shaken by hand for 10 minutes to redisperse the precipitate in the water. This yielded N2CT with three size distributions. X Dispersion.
[0136] S6: Preparation of N2CT X Ink, N2CT X A solution with a solute concentration of 1 mg / ml is prepared by mixing anhydrous ethanol and deionized water in a ratio of 3:7. The solution is then shaken by hand to disperse it evenly and set aside for later use.
[0137] S7: Inkjet Printing
[0138] S7-1: Place the substrate in a plasma chamber and treat it with oxygen plasma for 3 minutes;
[0139] S7-2: The needle diameter used is 20μm. The pre-designed printing pattern program is invoked, and the printing parameters are adjusted: nozzle amplitude is 3V, nozzle frequency is 450kHz, and speed is 0.75mm / s. -1 The printed MXene film area is 20μm×100μm. The printed MXene film is heat-treated at 90℃ for 30 minutes in a vacuum drying oven to enhance the adhesion between the substrate and MXene, and at the same time promote the evaporation of solvent.
[0140] S8: Constructing N2CT X Synaptic transistor:
[0141] S8-1: Use a pipette to drop 2 μL of Nafion 117 solution onto the channel layer, gate, and exposed substrate. The dielectric layer covers the channel layer and connects to the gate.
[0142] S8-3: Place the device in a vacuum drying oven and heat it at 90°C for 20 minutes to remove any unevaporated solution.
[0143] Example 6
[0144] This embodiment discloses a synaptic transistor based on MXene inkjet printing, which is prepared by the fabrication method described in any one of Examples 1-5.
[0145] In summary, this invention utilizes inkjet printing to fabricate synaptic transistors with MXene as the channel layer, avoiding the impact of traditional micro / nano fabrication processes such as photolithography and etching on the MXene material. Furthermore, it significantly simplifies the process flow and greatly reduces fabrication costs. The invention employs a self-developed narrow-diameter MXene material, etched into an ink without additional surfactants, to print uniform, continuous ultrathin patterns (5-15 nm) on various substrates. The inkjet-printed MXene synaptic transistors of this invention exhibit enhanced non-volatile retention time (10 nm). 2 s), and successfully simulated the biological behavior of the human brain.
[0146] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be within the scope of protection of the present invention.
Claims
1. A method for fabricating synaptic transistors based on MXene inkjet printing, characterized in that, It includes the following steps: S1: Select a substrate and clean the substrate; S2: The gate, source and drain on the substrate are patterned using photolithography. S3: Deposit the gate, source, and drain on the substrate; S4: Few-layer MXene was obtained by wet chemical etching combined with mechanical exfoliation of MAX phase material; S5: Obtain an MXene dispersion with a certain flake size distribution by liquid phase cascade centrifugation; S6: Prepare MXene ink using the MXene dispersion; S7: Perform hydrophilic treatment on the surface of the substrate, set the MXene film printing parameters, and print the MXene film at the channel position using the MXene ink; S8: Prepare an electrolyte solution and drop-cast a dielectric layer on the MXene channel layer, gate, and exposed substrate, wherein the dielectric layer covers the channel layer and connects to the gate to construct an MXene synaptic transistor; The deposition thickness of each electrode in step S3 is 30-60 nm; The MXene material mentioned in step S4 is Ti3C2T X V2CT X Nb2CT X Ti3CNT X One of them; the ratio of ethanol to water in the MXene ink is 1:9, 2:8, or 3:7; The printing parameters set in step S7 include amplitude and speed, where the amplitude is 0.5-5V and the speed is 0.01-1mms. -1 The thickness of the printed MXene thin film pattern is 5-15nm; In step S8, the dielectric layer is either Nafion 117 as the proton-donating layer or PEO / LiTFSI as the lithium-ion-donating layer, wherein the mass ratio of PEO to LiTFSI is 2.5-5:
1.
2. The method for fabricating synaptic transistors based on MXene inkjet printing according to claim 1, characterized in that, The substrate in step S1 is selected as an insulating rigid material.
3. The method for fabricating synaptic transistors based on MXene inkjet printing according to claim 2, characterized in that, The substrate can be any one of silicon oxide wafers, glass, ceramics, or sapphire substrates.
4. The method for fabricating synaptic transistors based on MXene inkjet printing according to claim 1 or 3, characterized in that, The substrate was sequentially cleaned with acetone, isopropanol, and deionized water, and then dried with nitrogen gas.
5. A synaptic transistor based on MXene inkjet printing, characterized in that, It is prepared by the preparation method described in any one of claims 1-4.