A method for preparing an artificial synaptic device with nanochannels

Abstract

The present invention is a method for preparing an artificial synaptic device with a nanochannel. The method uses polyvinyl carbazole and styrene to prepare a precursor solution, and then uses a high-resolution electrofluidic printing device to print a nanowire array on the prepared semiconductor layer. After the electrode is evaporated, the prepared nanoarray is torn off along the edge of the metal electrode using tape to obtain a nanochannel. The nanochannel prepared by the present invention has controllable size and neat arrangement, and can be applied to small-sized electronic devices, solving the problem of size limitation of electronic devices prepared by the prior art, and has the advantages of simple operation, simple process, and large-scale preparation, and the energy consumption of the artificial synaptic device with a nanochannel is greatly reduced.

Description

Technical field:

[0001] The invention belongs to the field of electronic devices, and in particular relates to an artificial synaptic electronic device with a nanochannel. Background technology:

[0002] Neuromorphic engineering is an important means of designing and manufacturing non-biological computing systems with highly parallel computing that is highly similar to the human brain. Artificial neuromorphic systems simulate the human brain's cognition, memory, computing and other complex functions at extremely high speed and efficiency. With the development of electronic and information technology, computers are still inferior to the human brain in terms of size, computing speed, and operating efficiency. Therefore, manufacturing computers with similar structures and functions to the brain may be an important direction for future development.

[0003] Interconnected neurons constitute the nervous system of the brain, which enables the brain to process various complex external problems in real time and make decisions on them. At the same time, the brain can also store and remember external information. Neuromorphic engineering systems inspired by biological nervous systems have attracted extensive research on robots and prostheses. Among them, based on the advantages of extremely small size (micrometer level) and low energy consumption (10fJ per synaptic event), the trillion-level brain basic units from human synapses can process most of the information in complex situations. Therefore, brain-like circuits or electronic devices have attracted a lot of attention recently. Organic core-sheath nanowire array artificial synapses are structurally very similar to biological synapses, and stretchable or optoelectronic synaptic devices have excellent short-term / long-term plasticity and flexible stability. However, these millimeter-scale devices are too large to be comparable to biological synapses, and the micrometer-scale channels of synaptic transistors cannot be comparable to the nanometer-scale biological synaptic gaps. As a result, it is impossible to make a breakthrough in the energy consumption of synaptic transistors, which in turn hinders the development of artificial neural networks. The development of small-sized and low-energy synaptic transistors is urgently needed to realize brain-like neuromorphic networks.

[0004] Based on this problem orientation, we use the independently developed digitally controllable nanowire printing technology to print functional conductive ink onto a substrate with a semiconductor layer to form a conductive channel for electronic components. This technology has the advantages of simple operation, low cost, personalization, and green environmental protection. It solves the problem of size limitation of artificial synaptic devices prepared by existing technologies, greatly reduces production costs, and improves material utilization. Summary of the invention:

[0005] The purpose of the present invention is to provide a method for digitally controllable printing of nanochannels of artificial synaptic devices in view of the shortcomings of the current technology. The method uses polyvinyl carbazole and styrene to prepare a precursor solution, and then uses a high-resolution electrofluidic printing device to print a nanowire array on a prepared semiconductor layer. After the electrode is evaporated, the prepared nanoarray is torn off along the edge of the metal electrode using a high-temperature tape to obtain a nanochannel. The nanochannel prepared by the present invention has controllable size and neat arrangement, and can be applied to small-sized electronic devices, which solves the problem of size limitation of electronic devices prepared by the prior art, has the advantages of simple operation, simple process, and large-scale preparation, and the energy consumption of artificial synaptic devices with nanochannels is greatly reduced.

[0006] The technical solution of the present invention is:

[0007] A method for preparing an artificial synaptic device with a nanochannel, characterized in that the method comprises the following steps:

[0008] (1) The substrate is ultrasonically cleaned with acetone and isopropyl alcohol (IPA) in sequence; the surface of the substrate is then fumigated with isopropyl alcohol hot vapor for 5 seconds to 3 minutes, and then the surface is blown dry with N2;

[0009] (2) cleaning the substrate obtained in step (1) with ultraviolet ozone, and then preparing a semiconductor layer on the substrate, wherein the thickness of the semiconductor layer is 50 to 500 nm;

[0010] (3) mixing polyvinyl carbazole and styrene, stirring at room temperature for 1-12 hours, to obtain a precursor solution; wherein the mass fraction of polyvinyl carbazole is 3%-6%;

[0011] (4) using an electrofluidic printing device to print the precursor solution on the semiconductor layer to obtain a nanowire array;

[0012] Wherein, the voltage between the syringe needle and the receiving surface is 0.8-5 kV, the distance between the syringe needle and the substrate is 2-6 mm, the flow rate of the syringe needle is set to 1-50 nl / min, and the substrate movement speed is set to 200-800 mm / s;

[0013] The diameter of the obtained nanowires is 50 to 5000 nm, and the spacing of the nanowire arrays is 500 to 5000 μm.

[0014] (5) evaporating electrodes, using a mask to evaporate metal electrodes on the surface of the nanowire array prepared in step (4);

[0015] The metal electrode is a gold electrode or an aluminum electrode with a thickness of 80-150 nm, a width of 3-5 mm, and a length of 6-10 mm.

[0016] (6) Use tape to peel off the nanowires to obtain an artificial synaptic device with nanochannels.

[0017] The adhesive tape is preferably made of polyimide.

[0018] The beneficial effects of the present invention are:

[0019] The present invention uses a method for digitally controllably printing nanochannels of artificial synaptic devices, mixes polyvinyl carbazole and styrene to prepare a precursor solution, then uses a high-resolution electrofluidic printing device to print a nanowire array on a prepared semiconductor layer, and after evaporating an electrode, uses a high-temperature adhesive tape to tear off the prepared nanoarray along the edge of the metal electrode to obtain a nanochannel. Different from the traditional method for preparing a conductive channel, the present invention does not require a mask with a specific channel pattern, and can adjust the size of the nanowire by adjusting the concentration of the precursor solution, the parameters during printing, etc., so as to obtain nanochannels with different aspect ratios; the present invention can be applied to electronic devices with small size and low power consumption requirements, solves the problem of size limitation of electronic devices prepared by the prior art, and has the advantages of simple operation, simple process, and large-scale preparation. Description of the drawings:

[0020] Figure 1 is a schematic cross-sectional view of a device obtained after a metal electrode is evaporated on the surface of the printed nanowire array in Example 1;

[0021] Figure 2 This is a schematic structural diagram of an artificial synaptic device with a nanochannel obtained by tearing off the nanowire covered with a metal electrode using adhesive tape in Example 1;

[0022] Figure 3 is a scanning electron microscope image of the nanowire array prepared on the semiconductor layer in Example 1;

[0023] Figure 4 This is a scanning electron microscope image of the nanochannel at 2500 times magnification obtained after evaporating the metal electrode in Example 1;

[0024] Figure 5 This is a scanning electron microscope image of the nanochannel at a magnification of 140,000 obtained after evaporating the metal electrode in Example 1;

[0025] Figure 6 The postsynaptic current performance comparison between the artificial synaptic device with a nanochannel and the artificial synaptic device with a conventional conductive channel in Example 1 is shown in FIG. 1 , and the pulse amplitude is 4V;

[0026] Among them, 1 is the substrate, 2 is the semiconductor layer, 3 is the metal electrode, 4 is the printed nanowire, and 5 is the nanochannel.

[0027] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments: Specific implementation method:

[0028] Embodiment 1:

[0029] (1) 2.0×2.0cm 2 The Si / SiO2 substrate was ultrasonically cleaned in an acetone solution for 15 min, and then ultrasonically cleaned in an isopropyl alcohol (IPA) solution for 15 min. The IPA was then heated to boiling, and the surface of the substrate was fumigated with IPA hot steam for 1 min. The surface was then blown dry with a N2 gun.

[0030] (2) Dissolve diethanolamine (2.45 mL) and tetrabutyl titanate (5.1 mL) in anhydrous ethanol (33.6 mL) in sequence under stirring, and then stir for 2 h. Then add anhydrous ethanol (5 mL) and ultrapure water (0.45 mL) to the solution, and stir the mixture for further 2 h, and then let it stand for 24 h; a transparent TiO2 precursor sol is obtained;

[0031] (3) The obtained 2.0×2.0cm 2 The Si / SiO2 substrate was placed in a UV ozone cleaning machine for 20 min, 100 μL of TiO2 precursor sol was taken on all the sprayed substrates using a pipette, and the reaction mixture was cleaned at 3000 r·min. -1 The silicon substrate was spin-coated at a speed of 30 s. After the spin coating was completed, the substrate was placed in a muffle furnace, calcined at 500 ° C for 60 min, and then cooled to room temperature to obtain a TiO2 film (i.e., semiconductor layer) with a thickness of about 50 nm on the silicon substrate. The entire spin coating process was carried out in a nitrogen glove box.

[0032] (4) mixing polyvinyl carbazole and styrene, and stirring at room temperature for 4 hours to obtain a precursor solution; wherein the mass fraction of polyvinyl carbazole is 3.5%;

[0033] (5) using an electro-hydraulic jet printing device (E-Jet) to digitally controllably print a nanowire array on the prepared semiconductor layer with the mixed solution, controlling the voltage between the syringe needle and the receiving surface to be 1.2 kV, the distance between the syringe needle and the substrate to be 2.5 mm, the flow rate of the syringe needle to be 20 nl / min, and the substrate movement speed to be 300 mm / s; in the obtained nanowire array, the diameter of the nanowire is 500 nm, the spacing of the nanowire array is 1500 μm, and the length of the nanowire is 2.0 cm;

[0034] (6) Using a mask, evaporate a gold electrode with a thickness of 80 nm, a width of 3 mm, and a length of 10 mm on the surface of the nanowire array of the device obtained in the previous step, such as Figure 1 As shown; wherein the length direction of the gold electrode is perpendicular to the direction of the nanowire, as shown Figure 2 shown.

[0035] (7) Use a 3 mm wide tape to stick to the nanowire from the edge of the metal electrode outward and along the direction of the nanowire. Then tear off the tape from the end away from the metal electrode from the outside to the inside along the edge of the metal electrode, that is, peel off the nanowires on the nanowire array on the semiconductor layer one by one (when peeling off the nanowires covered by the metal electrode, the gold covering them is also torn off linearly). The empty groove behind each peeled nanowire forms a conductive channel (thin semiconductor, which plays a conductive role). The metals on both sides of the nanowire serve as source and drain electrodes respectively, and an artificial synaptic device with a nanowire channel is obtained.

[0036] The structure of the obtained artificial synaptic device is, from bottom to top, a substrate, a TiO2 film (semiconductor layer), on which conductive channels (arrays) are distributed, and the upper surfaces on both sides of each conductive channel are source and drain metal electrodes.

[0037] The adhesive tape is specifically a gold finger high temperature resistant adhesive tape made of polyimide material, which has good viscosity, good conformability, short-term temperature resistance of 300°C, and long-term temperature resistance of 250°C.

[0038] Figure 3 This is a scanning electron microscope image of the nanowire array prepared on the semiconductor layer in Example 1. It can be seen that the printed nanowire array is evenly arranged, the spacing between the nanowires is about 1500 microns, and the diameter is about 500 nm.

[0039] Figure 4 and Figure 5 These are scanning electron microscope images of the nanochannels obtained after the metal electrodes are evaporated at different magnifications and the nanowires are torn off with tape. It can be seen that the width of the prepared nanochannels is uniform, about 500nm.

[0040] Figure 6 The postsynaptic current performance of an artificial synaptic device with a nanochannel is compared with that of an artificial synaptic device with a conventional conductive channel (the channel length is 40 μm and the width is 1500 μm, which needs to be obtained through a mask with a special pattern). It can be seen that when subjected to the same pulse amplitude (4V), compared with the artificial synaptic device with a conventional conductive channel, the artificial synaptic device with a nanochannel prepared by the present invention requires a driving voltage of one percent (0.01V) of the aforementioned device, and the value of the postsynaptic current generated is about 150 times that of the aforementioned device. This is due to the fact that the aspect ratio of the obtained nanoconductive channel is relatively large and the channel resistance is relatively small. Therefore, when receiving pulse stimulation, it can generate a large current at a small driving voltage. Among them, the performance of the above-mentioned artificial synaptic device is tested by a semiconductor analyzer with the model of Keithley4200A-SCS.

[0041] Embodiment 2:

[0042] (1) 2.0×2.0cm 2 The Si / SiO2 substrate was ultrasonically cleaned in an acetone solution for 15 min, and then ultrasonically cleaned in an isopropyl alcohol (IPA) solution for 15 min. The IPA was then heated to boiling, and the surface of the substrate was fumigated with IPA hot steam for 1 min. The surface was then blown dry with a N2 gun.

[0043] (2) Dissolve diethanolamine (2.45 mL) and tetrabutyl titanate (5.1 mL) in anhydrous ethanol (33.6 mL) in sequence under stirring, and then stir for 2 h. Then add anhydrous ethanol (5 mL) and ultrapure water (0.45 mL) to the solution, and stir the mixture for further 2 h, and then let it stand for 24 h; a transparent TiO2 precursor sol is obtained;

[0044] (3) The obtained 2.0×2.0cm 2 The Si / SiO2 substrate was placed in a UV ozone cleaning machine for 20 min, 100 μL of TiO2 precursor sol was taken on all the sprayed substrates using a pipette, and the reaction mixture was cleaned at 3000 r·min. -1 The substrate was spin-coated at a speed of 30 s. After the spin coating, it was placed in a muffle furnace, calcined at 500 ° C for 60 min, and then cooled to room temperature to obtain a TiO2 film on the silicon substrate with a thickness of about 50 nm. The entire spin coating process was carried out in a nitrogen glove box.

[0045] (4) mixing polyvinyl carbazole and styrene, and stirring at room temperature for 6 hours to obtain a precursor solution; wherein the mass fraction of polyvinyl carbazole is 4.5%;

[0046] (5) using an electro-hydraulic jet printing device (E-Jet) to digitally controllably print a nanowire array on the prepared semiconductor layer with the mixed solution, controlling the voltage between the syringe needle and the receiving surface to be 2.0 kV, the distance between the syringe needle and the substrate to be 3 mm, the flow rate of the syringe needle to be 50 nl / min, and the substrate movement speed to be 400 mm / s, the nanowire array having a diameter of 550 nm, a spacing of 2000 μm, and a length of 2.0 cm;

[0047] (6) using a mask to evaporate a gold electrode with a thickness of 80 nm, a width of 3 mm, and a length of 10 mm on the surface of the device nanowire array obtained in the previous step;

[0048] (7) Use a 3 mm wide tape to stick to the nanowire from the edge of the metal electrode outward and along the direction of the nanowire. Then tear off the tape from the end away from the metal electrode from the outside to the inside along the edge of the metal electrode, that is, peel off the nanowires on the nanowire array on the semiconductor layer one by one (when peeling off the nanowires covered by the metal electrode, the gold covering them is also torn off linearly). The empty groove behind each peeled nanowire forms a conductive channel (thin semiconductor, which plays a conductive role). The metals on both sides of the nanowire serve as source and drain electrodes respectively, and an artificial synaptic device with a nanowire channel is obtained.

[0049] The structure of the obtained artificial synaptic device is, from bottom to top, a substrate, a TiO2 film (semiconductor layer), on which conductive channels (arrays) are distributed, and the upper surfaces on both sides of each conductive channel are source and drain metal electrodes.

[0050] The adhesive tape is specifically a gold finger high temperature resistant adhesive tape made of polyimide material, which has good viscosity, good conformability, short-term temperature resistance of 300°C, and long-term temperature resistance of 250°C.

[0051] Embodiment 3:

[0052] (1) 2.0×2.0cm 2 The Si / SiO2 substrate was ultrasonically cleaned in an acetone solution for 15 min, and then ultrasonically cleaned in an isopropyl alcohol (IPA) solution for 15 min. The IPA was then heated to boiling, and the surface of the substrate was fumigated with IPA hot steam for 1 min. The surface was then blown dry with a N2 gun.

[0053] (2) Dissolve diethanolamine (2.45 mL) and tetrabutyl titanate (5.1 mL) in anhydrous ethanol (33.6 mL) in sequence under stirring, and then stir for 2 h. Then add anhydrous ethanol (5 mL) and ultrapure water (0.45 mL) to the solution, and stir the mixture for further 2 h, and then let it stand for 24 h; a transparent TiO2 precursor sol is obtained;

[0054] (3) The obtained 2.0×2.0cm 2 The Si / SiO2 substrate was placed in a UV ozone cleaning machine for 20 min, 100 μL of TiO2 precursor sol was taken on all the sprayed substrates using a pipette, and the reaction mixture was cleaned at 3000 r·min. -1 The substrate was spin-coated at a speed of 30 s. After the spin coating, it was placed in a muffle furnace, calcined at 500 ° C for 60 min, and then cooled to room temperature to obtain a TiO2 film on the silicon substrate with a thickness of about 50 nm. The entire spin coating process was carried out in a nitrogen glove box.

[0055] (4) Mix polyvinyl carbazole and styrene, and stir at room temperature for 8 hours to obtain a precursor solution; wherein the mass fraction of polyvinyl carbazole is 6.0%

[0056] (5) using an electro-hydraulic jet printing device (E-Jet) to digitally controllably print a nanowire array on the prepared semiconductor layer with the mixed solution, controlling the voltage between the syringe needle and the receiving surface to be 2.2 kV, the distance between the syringe needle and the substrate to be 2.5 mm, the flow rate of the syringe needle to be 80 nl / min, and the substrate movement speed to be 300 mm / s, the nanowire array having a diameter of 800 nm, a spacing of 2000 μm, and a length of 2.0 cm;

[0057] (6) using a mask to evaporate a gold electrode with a thickness of 80 nm, a width of 3 mm, and a length of 10 mm on the surface of the device nanowire array obtained in the previous step;

[0058] (7) Use a 3 mm wide tape to stick it on the nanowire from the edge of the metal electrode outward and along the direction of the nanowire. Then tear off the tape from the end away from the metal electrode from the outside to the inside along the edge of the metal electrode. That is, the nanowires on the nanowire array on the semiconductor layer are peeled off one by one (when peeling off the nanowires covered by the metal electrode, the gold covering them is also torn off linearly). The empty groove behind each peeled nanowire forms a conductive channel (thin semiconductor, which plays a conductive role). The metals on both sides of the nanowire serve as source and drain electrodes respectively, and an artificial synaptic device with a nanowire channel is obtained.

[0059] The structure of the obtained artificial synaptic device is, from bottom to top, a substrate, a TiO2 film (semiconductor layer), on which conductive channels (arrays) are distributed, and the upper surfaces on both sides of each conductive channel are source and drain metal electrodes.

[0060] The adhesive tape is specifically a gold finger high temperature resistant adhesive tape made of polyimide material, which has good viscosity, good conformability, short-term temperature resistance of 300°C, and long-term temperature resistance of 250°C.

[0061] Matters not covered by the present invention are known technologies.

Claims

1. A method for preparing an artificial synaptic device having a nanochannel, characterized in that the method comprises the following steps: (1) The substrate is ultrasonically cleaned with acetone and isopropyl alcohol (IPA) in sequence; the surface of the substrate is then fumigated with isopropyl alcohol hot vapor for 5 seconds to 3 minutes, and then the surface is blown dry with N2; (2) cleaning the substrate obtained in step (1) with ultraviolet ozone, and then preparing a semiconductor layer on the substrate, wherein: The thickness of the semiconductor layer is 50 to 500 nm; (3) mixing polyvinyl carbazole and styrene, stirring at room temperature for 1-12 hours, to obtain a precursor solution; wherein the mass fraction of polyvinyl carbazole is 3%-6%; (4) using an electrofluidic printing device to print the precursor solution on the semiconductor layer to obtain a nanowire array; Wherein, the voltage between the syringe needle and the receiving surface is 0.8-5 kV, the distance between the syringe needle and the substrate is 2-6 mm, the flow rate of the syringe needle is set to 1-50 nl / min, and the substrate movement speed is set to 200-800 mm / s; (5) evaporating electrodes, using a mask to evaporate metal electrodes on the surface of the nanowire array prepared in step (4); (6) Use tape to peel off the nanowires to obtain an artificial synaptic device with nanochannels.

2. The method for preparing an artificial synaptic device with a nanochannel according to claim 1, characterized in that The diameter of the nanowires obtained in step (4) is 50 to 5000 nm, and the spacing of the nanowire array is 500 to 5000 μm.

3. The method for preparing an artificial synaptic device with a nanochannel according to claim 1, characterized in that The metal electrode in step (5) is a gold electrode or an aluminum electrode with a thickness of 80-150 nm. The metal electrode is 3-5 mm wide and 6-10 mm long.

4. The method for preparing an artificial synaptic device with a nanochannel as claimed in claim 1, wherein the tape in step (6) is preferably made of polyimide.

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