A copper tin sulfur (CTS) memristor and its preparation method

Abstract

The present invention provides a copper-tin-sulfur (CTS) memristor and a preparation method thereof. The memristor comprises, from top to bottom, an Al top electrode, a CTS-PMMA resistive switching layer, and a FTO bottom electrode. CTS nanoparticles are prepared using a traditional hydrothermal method, and CTS and PMMA are combined for the first time and applied to the memristor field. Experimental results show that by mixing CTS and PMMA, a memristor device with excellent resistive switching performance and strong stability is obtained. Furthermore, controlling the thickness of the resistive switching film can optimize the resistive switching performance. This memristor device has the advantages of simple structure, easy preparation, low cost, and good reproducibility, and may provide new ideas for the development of chalcogenide-based memristors and their applications.

Description

Technical Field

[0001] The present invention belongs to the technical field of memristors, and more particularly, relates to a copper tin sulfide (CTS) memristor and a preparation method thereof. Background Art

[0002] Resistive random access memory (RRAM) is an emerging and promising non-volatile memory. Due to its advantages such as high endurance, fast switching speed, low power consumption, simple structure, and compact memory, it has attracted widespread attention and is considered the most promising candidate for future storage technology. To meet the stringent requirements and huge demand for higher density, faster speed, and lower power non-volatile memory, research into new memory technologies is necessary. Memristors, as one of the four basic components, have developed rapidly despite a relatively recent development. A typical memristor is a two-terminal device consisting of an electrode / resistive layer / electrode (M / I / M) structure. It achieves non-volatile data storage by reversibly switching between high and low resistance states in the resistive layer when an external field is applied, and retaining the resistive state in real time when the field is removed. While the memristor structure appears simple, variations in the resistive layer material and microstructure, as well as differences in electrode materials and electrode-resistive layer interface properties, can affect its resistive switching performance to varying degrees, leading to complexity and difficulty in identifying the resistive switching mechanism. As we all know, the understanding of the working mechanism and microscopic mechanism of memristors is inseparable from the specific materials used. Experimental studies have found that a variety of materials can be used for the resistive switching layer of memristors. Currently, the research on inorganic materials with resistive switching properties can be divided into binary oxides (such as TiO x 、TaO x ), multi-element oxides (such as SrTiO3 and BiMnO3), binary sulfides (Cu2S and MoS2), and nitrides (such as AlN and SiN), with extensive research on binary oxides. While significant progress has been made in both basic and applied research on memristors, there is still a significant gap to commercialization. The development of new materials and the exploration of new principles and processes for structural modification, such as introducing defects, surface modification, and interface barriers, are still necessary to continuously improve the reliability, stability, and service life of the non-volatile resistive switching performance of memristor materials.

[0003] Copper tin sulfide (Cu3SnS4, CTS) is a p-type direct bandgap polysulfide semiconductor material. Due to its abundant content in the Earth's crust, environmental friendliness, low cost, and high light absorption coefficient, it is widely used in thin-film solar cells and holds great potential for development. However, research on the resistive switching performance of CTS in memristors is rare. Polymethyl methacrylate (PMMA) has garnered widespread attention in electronic device applications due to its low cost, high transparency, and ease of processing. In recent years, numerous memristor devices fabricated using PMMA thin films have been reported. Research has shown that by incorporating metal compounds (such as ZnO, MoSe2, MoS2, and SnO2) into PMMA thin films, memristors with improved resistive switching performance and enhanced stability have been achieved. Summary of the Invention

[0004] The purpose of the present invention is to prepare Cu3SnS4 (CTS) powder by a hydrothermal method, then mix and stir polymethyl methacrylate (PMMA) solution with CTS powder, and then use a spin coating process to deposit a CTS-PMMA resistive layer film on an FTO (fluorine-doped tin oxide) substrate. Finally, a point-shaped Al electrode is deposited by vacuum evaporation to obtain a memristive device with an Al / CTS-PMMA / FTO structure and perform resistive performance testing.

[0005] In the present invention, the terms "copper tin sulfur" and "CTS" both refer to Cu3SnS4.

[0006] To achieve this goal, this technology employs a simple, low-cost method for preparing CTS powder. This method produces a CTS-PMMA composite film on a FTO substrate, which exhibits excellent memristive properties under applied voltage. The resulting memristive device exhibits a novel structure, stable resistive switching performance, and a large switching ratio. The switching ratio and resistive switching stability can be adjusted by controlling the CTS and PMMA composite concentrations and the number of spin-coating cycles.

[0007] The present invention adopts the following technical solutions:

[0008] A method for preparing a copper tin sulfide memristor comprises the following steps:

[0009] Step 1: preparing a copper-tin-sulfur precursor solution: dissolving a copper source, a tin source, and a sulfur source in an organic solvent and stirring to obtain a copper-tin-sulfur precursor solution;

[0010] Step 2: Preparing copper, tin, and sulfur powder: Pour the copper, tin, and sulfur precursor solution prepared in step 1 into a hydrothermal reactor and place it in a hydrothermal box for hydrothermal reaction. After the reaction is completed, the mixture is naturally cooled, the supernatant is discarded, and the remaining mixture is centrifuged, washed, and dried to obtain a black powder. The black powder is ground to obtain copper, tin, and sulfur nanoparticles;

[0011] Step 3: preparing a polymethyl methacrylate solution: dissolving polymethyl methacrylate particles in an organic solvent to obtain a polymethyl methacrylate solution;

[0012] Step 4: preparing a copper-tin-sulfur and polymethyl methacrylate composite solution: adding the copper-tin-sulfur nanoparticles prepared in step 2 to the polymethyl methacrylate solution prepared in step 3, stirring at room temperature to obtain a copper-tin-sulfur and polymethyl methacrylate composite solution;

[0013] Step 5: Clean the FTO conductive glass substrate;

[0014] Step 6: Preparing a copper-tin-sulfur-polymethyl methacrylate composite resistive film: dripping the copper-tin-sulfur and polymethyl methacrylate composite solution prepared in step 4 onto the conductive surface of the FTO conductive glass substrate cleaned in step 5, spin coating, and drying at room temperature to prepare a copper-tin-sulfur-polymethyl methacrylate composite resistive film, thereby obtaining a copper-tin-sulfur-polymethyl methacrylate composite resistive film / FTO structure; wherein the conductive surface of the FTO conductive glass substrate is the back electrode;

[0015] Step 7: Assembling Al / copper tin sulfur-polymethyl methacrylate composite resistive film / FTO memristive device: further depositing an upper electrode on the copper tin sulfur-polymethyl methacrylate composite resistive film / FTO structure obtained in step 6, wherein the upper electrode is deposited on the copper tin sulfur-polymethyl methacrylate composite resistive film; the upper electrode is made of Al.

[0016] Furthermore, in step 1, the copper source is Cu(CH3COO)2·H2O.

[0017] Preferably, in step 1, the tin source is SnCl2.

[0018] Preferably, in step 1, the sulfur source is CH4-N2S.

[0019] Preferably, in step 1, the organic solvent is N-N-dimethylamide.

[0020] Preferably, in step 1, the copper tin sulfur is Cu3SnS4.

[0021] Furthermore, in step 2, the temperature of the hydrothermal reaction is 170-190°C.

[0022] Preferably, in step 2, the hydrothermal reaction time is 23 to 25 hours.

[0023] Furthermore, in step 3, the organic solvent is chloroform.

[0024] Preferably, in step 3, the concentration of the polymethyl methacrylate solution is 1 to 6 mg / mL.

[0025] Furthermore, in step 4, the mass ratio of the added copper, tin, and sulfur powder to the added polymethyl methacrylate is 1 to 4. For example, 1, 1.5, 2, 2.5, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, or 4.

[0026] Furthermore, in step 5, the FTO conductive glass is placed in a container filled with detergent water, and then placed in an ultrasonic tank for ultrasonic treatment. The detergent water in the container is then replaced with an alcohol solution and ultrasonic treatment is continued. The glass is then rinsed with deionized water and blown dry with nitrogen.

[0027] Furthermore, in step 6, the rotation speed of the spin coating is 2000-4000 rpm.

[0028] Preferably, in step 6, the spin coating time is 10 to 60 seconds.

[0029] Furthermore, in step 7, the deposition is performed by vacuum evaporation.

[0030] Preferably, step 7 specifically includes: first placing the copper tin sulfur-polymethyl methacrylate composite resistive film / FTO structure into a dotted Al electrode deposition mask, and vacuum coating, thereby obtaining a memristive device of the Al / copper tin sulfur-polymethyl methacrylate composite resistive film / FTO structure.

[0031] Preferably, in step 7, there are a plurality of upper electrodes, and the plurality of upper electrodes are dispersedly arranged on the copper-tin-sulfur-polymethyl methacrylate composite resistive film.

[0032] An Al / copper tin sulfur-polymethyl methacrylate composite resistive film / FTO memristive device prepared by the method as described in any of the above items, wherein the memristive device includes an FTO conductive glass conductive layer, a copper tin sulfur-polymethyl methacrylate composite resistive film layer arranged on the FTO conductive layer, and an upper electrode arranged on the composite resistive film layer.

[0033] Furthermore, the thickness of the composite resistive film layer is 300-700 nm.

[0034] For example, the thickness of the composite resistive film layer is 300nm, 310nm, 320nm, 330nm, 340nm, 350nm, 360nm, 370nm, 380nm, 390nm, 400nm, 410nm, 420nm, 430nm, 440nm, 450nm, 460nm, 470nm, 480nm, 490nm, 500nm, 550nm, 600nm, 650nm or 700nm.

[0035] Specifically, a method for preparing a copper tin sulfide memristor is carried out according to the following steps:

[0036] Step 1: Preparation of CTS precursor solution: Dissolve Cu(CH3COO)2·H2O, SnCl2, and CH4-N2S in 30 mL of N-N-dimethylamide in sequence and stir at room temperature for 12 hours to obtain the precursor solution for hydrothermal growth of CTS.

[0037] Step 2: Hydrothermal growth of CTS nanoparticles. Transfer all the precursor solution prepared in step 1 to a hydrothermal reactor with a volume of 35 mL. Then seal the hydrothermal reactor and place it in a hydrothermal box. The temperature of the hydrothermal box is set to 180°C and the reaction time is 24 hours. Thereafter, remove the hydrothermal reactor from the hydrothermal box, cool it naturally to room temperature, pour out the supernatant, place the remaining mixture in a centrifuge tube and centrifuge it four times with water, alcohol, water, and alcohol, and then dry it to obtain a black powder. Finally, grind it several times to obtain CTS nanoparticles.

[0038] Step 3: Preparation of PMMA solution: 5 mL of chloroform solvent was added to a 20 mL glass bottle, followed by 20 mg of PMMA particles and thorough stirring to obtain a PMMA solution with a concentration of 4 mg / mL.

[0039] Step 4: Preparation of CTS-PMMA composite solution: 0.0742 g of the CTS powder prepared in step 2 was added to the PMMA solution in step 3 and stirred at room temperature for 24 hours to obtain a CTS-PMMA composite solution with a mass ratio of CTS nanoparticles to PMMA particles of 3.7.

[0040] Step 5: Cutting and Cleaning the FTO Substrate: Cut the FTO conductive glass into 2cm x 2cm pieces. Place the cut FTO conductive glass into a beaker filled with detergent and water. Ultrasonicate the glass in an ultrasonic bath for 15 minutes. Replace the detergent water with anhydrous ethanol and continue ultrasonicating for another 15 minutes. Rinse with deionized water and dry with nitrogen.

[0041] Step 6: Deposition of the CTS-PMMA resistive thin film. This resistive thin film is deposited using a spin coating method. The specific steps are as follows: Use a disposable plastic dropper to draw up the CTS-PMMA composite solution and drip it onto the conductive surface of the FTO conductive glass, completely covering the surface. Start the spin coater at 3000 rpm for 30 seconds, and dry it at room temperature for 2 minutes. This spin coating and drying process can be repeated multiple times to obtain resistive thin films of varying thicknesses.

[0042] Step 7: Assembly of Al / CTS-PMMA / FTO memristor device. The top electrode is further deposited on the CTS-PMMA / FTO structure obtained in step 6. The Al top electrode is deposited by vacuum evaporation. First, the CTS-PMMA / FTO structure is placed in a dot-shaped Al electrode deposition mask, fixed in a vacuum coating machine, and the vacuum coating machine is started. When the vacuum degree reaches 2.1×10 -3 Pa, the coating process begins and is maintained for 15 minutes, thereby obtaining a memristive device with Al / CTS-PMMA / FTO structure.

[0043] The excellent results of the present invention are: using Cu, Sn, and S compounds as raw materials, the raw materials are easy to obtain and the price is low; the CTS compound is synthesized by a traditional hydrothermal method, and the preparation method is easy to operate and low in cost; the present invention is the first to composite CTS and PMMA and apply it to the field of memristors. Test results show that it has excellent resistive switching performance and photoelectric field response, and the switching ratio and the stability of the resistive switching performance can be adjusted by controlling the concentration of CTS and the thickness of the CTS-PMMA composite film. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 Schematic diagram of the Al / CTS-PMMA / FTO memristor structure provided by Example 1 and Example 2 of the present invention.

[0045] Figure 2 This is a current-voltage characteristic curve of the CTS-PMMA film prepared by repeating the spin coating process 5 times in Example 1, and then assembling the Al / CTS-PMMA / FTO structure memristor.

[0046] Figure 3 This is a current-voltage characteristic curve of the CTS-PMMA film prepared by repeating the spin coating process 7 times in Example 2, and then assembling the Al / CTS-PMMA / FTO structure memristor. DETAILED DESCRIPTION

[0047] In order to make the preparation sequence and other contents of the present invention more clearly understood, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0048] First, according to the invention, the CTS powder described in the summary is prepared using a traditional hydrothermal method, which is easy to operate and low-cost. This invention provides a novel memristor comprising a bottom electrode, an inorganic chalcogenide and polymer composite layer, and a top electrode layer arranged from bottom to top. The bottom electrode is made of transparent FTO conductive glass; the resistive switching layer is a CTS and PMMA composite film. During the resistive switching layer preparation process, the thickness of the composite film and the CTS concentration can be manipulated to improve the stability of the resistive switching performance and increase the on / off ratio. The top electrode is an aluminum electrode layer. Finally, the resistive switching performance of the Al / CTS-PMMA / FTO memristor was tested using an electrochemical workstation to obtain current-voltage curves.

[0049] Figure 1 This is a schematic diagram of the Al / CTS-PMMA / FTO memristor structure provided in Examples 1 and 2 of the present invention. As shown, the Al / CTS-PMMA / FTO memristor includes an FTO conductive glass layer, a copper-tin-sulfur-polymethyl methacrylate composite resistive film layer disposed on the FTO conductive glass layer, and a top electrode disposed on the composite resistive film layer. Optionally, multiple top electrodes are dispersed across the copper-tin-sulfur-polymethyl methacrylate composite resistive film layer.

[0050] Example 1:

[0051] First, 0.06g Cu(CH3COO)2·H2O, 0.0274g SnCl2, and 0.03g CH4-N2S were dissolved in 30mL NN dimethylamide and stirred thoroughly at room temperature to form a CTS hydrothermal growth precursor solution; then all the precursor solution was transferred to a hydrothermal reactor with a volume of 35mL, and then the hydrothermal reactor was closed and placed in a hydrothermal box. The temperature of the hydrothermal box was set to 180℃, and the precursor solution was placed in the hydrothermal reactor at a temperature of 180℃ for 24 hours; then, the hydrothermal reactor was taken out from the hydrothermal box, naturally cooled to room temperature, the supernatant was poured out, and the remaining mixture was placed in a centrifuge tube and centrifuged and washed four times with water, alcohol, water, and alcohol. After drying, a black powder was obtained, and finally, CTS nanoparticles with an average particle size of about 170nm were obtained by grinding; then 5mL of chloroform solvent was added to a 20mL glass bottle, and then 20mg PMMA particles (average particle size 2.5 mm, Aladdin reagent, specification MW35000) were added and stirred thoroughly to obtain a PMMA solution with a concentration of 4 mg / mL; then 0.0742 g of the prepared CTS nanoparticles were added to the PMMA solution and stirred at room temperature for 24 hours to obtain a CTS-PMMA composite solution with a CTS to PMMA mass ratio of 3.7; then the FTO glass was cut into 2 cm × 2 cm pieces, the cut FTO glass was placed in a beaker filled with detergent water, and then placed in an ultrasonic tank for ultrasonic treatment for 15 minutes, and then the detergent water in the beaker was replaced with anhydrous ethanol and ultrasonicated for another 15 minutes, and then rinsed with deionized water and finally dried with nitrogen. The conductive layer of FTO conductive glass was used as the back electrode. A disposable plastic dropper was used to absorb the CTS-PMMA composite solution and drop it onto the FTO back electrode to completely cover the surface. The spin coating machine was started at a speed of 3000 rpm and a spin coating time of 30 seconds. The coating was dried at room temperature for 2 minutes. The spin coating and drying process was repeated 5 times to obtain a CTS-PMMA resistive switching film with a thickness of about 400 nm. An Al top electrode was deposited on the surface of the film structure by vacuum evaporation. First, the CTS-PMMA / FTO structure was placed in a dot-shaped Al electrode deposition mask and fixed in a vacuum coating machine (Beijing Beiyi Innovation Vacuum Technology Co., Ltd., Model DM-300B). When the vacuum degree reached 2.1×10 -3 Pa, the coating process began and was maintained for 15 minutes, thereby obtaining an Al / CTS-PMMA / FTO structured memristive device with a top electrode thickness of 80 nm. Finally, the current-voltage characteristics of the prepared memristive device were tested by cyclic voltammetry using an electrochemical workstation (Metrohm, model PGSTAT302N) to study its resistive switching performance.

[0052] Figure 2The current-voltage characteristic curve of the memristor device prepared in this embodiment (scan step size: 3mV, scan direction: 0V→-3V→0V→3V→0V), including 100 cycle curves, is shown. Analysis of the test curve data shows that the memristor has obvious set and reset voltages, and when a positive voltage is applied, a negative differential resistance phenomenon occurs, that is, the current decreases as the voltage increases. Compared with the curve in Example 2, although the cycle stability of this memristor is slightly worse, the on-off ratio is larger. Analysis shows that this is because the resistive switching layer is thin, and the current channel is more easily damaged or broken down as the number of cycles increases. It can be concluded that the memristor has relatively stable resistive switching performance, with an on-off ratio of 475.

[0053] Example 2:

[0054] First, 0.06g Cu(CH3COO)2·H2O, 0.0274g SnCl2, and 0.03g CH4-N2S were dissolved in 30mL NN dimethylamide and stirred thoroughly at room temperature to form a CTS hydrothermal growth precursor solution; then all the precursor solution was transferred to a hydrothermal reactor with a volume of 35mL. The hydrothermal reactor was then closed and placed in a hydrothermal box. The temperature of the hydrothermal box was set to 180℃. The precursor solution was placed in the hydrothermal reactor at a temperature of 180℃ for 24 hours; then, the hydrothermal reactor was removed from the hydrothermal box, cooled naturally to room temperature, the supernatant was poured out, and the remaining mixture was placed in a centrifuge tube and centrifuged four times with water, alcohol, water, and alcohol. After drying, a black powder was obtained. Finally, CTS nanoparticles with an average particle size of 170nm were obtained after multiple grinding; then 5mL of chloroform solvent was added to a 20mL glass bottle, and then 20mg PMMA particles (average particle size 2.5 mm, Aladdin reagent, specification MW35000) were mixed and stirred thoroughly to obtain a PMMA solution with a concentration of 4 mg / mL; then 0.0742 g of the prepared CTS powder was added to the PMMA solution and stirred at room temperature for 24 hours to obtain a CTS-PMMA composite solution with a CTS to PMMA mass ratio of 3.7; then the FTO glass was cut into 2 cm × 2 cm pieces, the cut FTO glass was placed in a beaker filled with detergent water, and then placed in an ultrasonic tank for ultrasonic treatment for 15 minutes, and then the detergent water in the beaker was replaced with anhydrous ethanol and ultrasonicated for another 15 minutes, and then rinsed with deionized water and finally dried with nitrogen. The conductive surface of FTO glass was used as the back electrode. A disposable plastic dropper was used to absorb the CTS-PMMA composite solution and drop it on the FTO back electrode to completely cover the surface. The spin coating machine was started and the spin coating speed was 3000 rpm. The spin coating time was 30 seconds and the film was dried at room temperature for 2 minutes. The spin coating and drying process was repeated 7 times to obtain a CTS-PMMA resistive switching film with a thickness of 480 nm. An Al top electrode was deposited on the surface of the film structure by vacuum evaporation. First, the CTS-PMMA / FTO structure was placed in a dot-shaped Al electrode deposition mask and fixed in a vacuum coating machine. The vacuum coating machine (Beijing Beiyi Innovation Vacuum Technology Co., Ltd., model DM-300B) was started. When the vacuum degree reached 2.1×10 -3 Pa, the coating work started and was maintained for 15 minutes, thereby obtaining an Al / CTS-PMMA / FTO structured memristive device with a top electrode thickness of 80 nm; finally, the current-voltage characteristics of the prepared memristive device were tested by cyclic voltammetry using an electrochemical workstation (Metrohm, Switzerland, model PGSTAT302N) to study its resistive switching performance.

[0055] Figure 3The current-voltage characteristic curve of the memristor device prepared in this example (step size: 3mV; scanning direction: 0V→-3V→0V→3V→0V), including 100 cycle curves, is shown. Through analysis of the test curve data, the memristor has obvious set voltage and reset voltage, and when a positive voltage is applied, a negative differential resistance phenomenon occurs, that is, the current decreases as the voltage increases. Compared with the curve in Example 1, the resistive switching performance has better cyclic stability. Analysis shows that this is because the resistive switching layer is thicker, and the original current channel is difficult to be destroyed or broken down after multiple cycles. It can be concluded that the memristor has stable resistive switching performance and an on-off ratio of 60.

[0056] Obviously, the technology of the present invention is a simple, low-cost new memristor preparation process, and the prepared Al / CTS-PMMA / FTO memristor device has a novel structure, stable resistive switching performance, low set voltage and reset voltage, and the switching ratio can be adjusted by regulating the number of spin coating times of the composite film. It has great application value in artificial neural synaptic computing systems.

[0057] The present invention does not describe in detail parts that belong to the common knowledge of those skilled in the art. The above-described embodiments are merely descriptions of preferred embodiments of the present invention. The preferred embodiments do not describe all details in detail, nor do they limit the invention to the specific embodiments described. Without departing from the spirit of the present invention, various modifications and improvements made by those skilled in the art to the technical solution of the present invention should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a copper tin sulfide memristor, characterized in that: The following steps are involved: Step 1: preparing a copper-tin-sulfur precursor solution: dissolving a copper source, a tin source, and a sulfur source in an organic solvent and stirring to obtain a copper-tin-sulfur precursor solution; Step 2: Preparing copper, tin, and sulfur powder: Pour the copper, tin, and sulfur precursor solution prepared in step 1 into a hydrothermal reactor and place it in a hydrothermal box for hydrothermal reaction. After the reaction is completed, cool naturally, remove the supernatant, centrifuge and wash the remaining mixture, dry it, and obtain a black powder. Grind the black powder to obtain copper, tin, and sulfur nanoparticles. Step 3: preparing a polymethyl methacrylate solution: dissolving polymethyl methacrylate particles in an organic solvent to obtain a polymethyl methacrylate solution; Step 4: preparing a copper-tin-sulfur and polymethyl methacrylate composite solution: adding the copper-tin-sulfur nanoparticles prepared in step 2 to the polymethyl methacrylate solution prepared in step 3, stirring at room temperature to obtain a copper-tin-sulfur and polymethyl methacrylate composite solution; Step 5: Clean the FTO conductive glass substrate; Step 6: Preparing a copper-tin-sulfur-polymethyl methacrylate composite resistive film: dripping the copper-tin-sulfur and polymethyl methacrylate composite solution prepared in step 4 onto the conductive surface of the FTO conductive glass substrate cleaned in step 5, spin coating, and drying at room temperature to prepare a copper-tin-sulfur-polymethyl methacrylate composite resistive film, thereby obtaining a copper-tin-sulfur-polymethyl methacrylate composite resistive film / FTO structure; wherein the conductive surface of the FTO conductive glass substrate is the back electrode; Step 7: Assembling Al / copper tin sulfur-polymethyl methacrylate composite resistive film / FTO memristive device: further depositing an upper electrode on the copper tin sulfur-polymethyl methacrylate composite resistive film / FTO structure obtained in step 6, wherein the upper electrode is deposited on the copper tin sulfur-polymethyl methacrylate composite resistive film; the upper electrode is made of Al.

2. The method according to claim 1, characterized in that In step 1, the copper source is Cu(CH3COO)2•H2O; The tin source is SnCl2; The sulfur source is CH4-N2S; The organic solvent is NN dimethylamide; The copper tin sulfur is Cu3SnS4.

3. The method according to claim 1, characterized in that In step 2, the temperature of the hydrothermal reaction is 170° C. to 190° C.; The hydrothermal reaction time is 23 hours to 25 hours.

4. The method according to claim 1, wherein In step 3, the organic solvent is chloroform; and the concentration of the polymethyl methacrylate solution is 1 mg / mL to 6 mg / mL.

5. The method according to claim 1, wherein In step 4, the mass ratio of the added copper, tin and sulfur powder to the added polymethyl methacrylate is 1 to 4.

6. The method according to claim 1, characterized in that In step 5, the FTO conductive glass is placed in a container filled with detergent water, and then placed in an ultrasonic tank for ultrasonic treatment. The detergent water in the container is then replaced with an alcohol solution and ultrasonic treatment is continued. The glass is then rinsed with deionized water and dried with nitrogen.

7. The method according to claim 1, characterized in that In step 6, the spin coating speed is 2000~4000rpm; The spin coating time is 10 to 60 seconds.

8. The method according to claim 1, characterized in that Step 7 specifically includes: firstly placing a copper-tin-sulfur-polymethyl methacrylate composite resistive film / FTO structure into a dot-shaped Al electrode deposition mask, and vacuum coating the film, thereby obtaining a memristive device of the Al / copper-tin-sulfur-polymethyl methacrylate composite resistive film / FTO structure; There are multiple upper electrodes, and the multiple upper electrodes are dispersedly arranged on the copper-tin-sulfur-polymethyl methacrylate composite resistive film.

9. The Al / copper tin sulfur-polymethyl methacrylate composite resistive film / FTO memristive device prepared by the method according to any one of claims 1 to 8, characterized in that: The memristor device comprises an FTO conductive glass layer, a copper tin sulfur-polymethyl methacrylate composite resistive film layer arranged on the FTO conductive glass layer, and an upper electrode arranged on the composite resistive film layer.

10. The device according to claim 9, characterized in that The thickness of the composite resistive film layer is 300-700 nm.

Images