CN115132919A - Light-operated artificial synapse device and preparation method thereof - Google Patents

Abstract

The invention discloses a light-controlled artificial synapse device and a preparation method thereof. The light-controlled artificial synapse device comprises: an inert electrode; a transparent electrode; , which is used to simulate synapses. The light-controlled artificial synapse device of the invention can apply a positive voltage to the inert electrode, the transparent electrode is grounded, the photoelectric memristive layer forms a conductive channel under the action of the electric field, the conductance rises, and the reversible light-gating control is realized under the control of ultraviolet light and visible light. activate/inhibit. The light-controlled artificial synapse device of the present invention has a two-terminal structure, and the structure is simple, the device size can be reduced to the nanometer level, and the power consumption is small. Brain-like computing systems provide the device foundation. Since the multi-dimensional adjustment of light, electricity, temperature and humidity can be realized based on the composite of common materials, it has a good application prospect in the field of new optoelectronic materials in the future.

Description

A kind of light-controlled artificial synapse device and preparation method thereof

technical field

The invention belongs to the technical field of the field of microelectronic materials and devices, and in particular relates to a light-controlled artificial synapse device and a preparation method thereof.

Background technique

Brain-inspired research is the research frontier in the field of artificial intelligence, and the construction of artificial neural synapses provides a hardware basis for neuromorphic computing. Synaptic systems — also known as artificial neural networks — are computing systems that allow electronic systems to work essentially in a manner similar to a biological brain. Synaptic systems can be composed of various electronic circuits for modeling biological neurons and synapses. Existing artificial synaptic devices are all based on electrical signal synaptic function simulation, with low tunability and accuracy.

SUMMARY OF THE INVENTION

(1) Purpose of the invention

The purpose of the present invention is to provide a light-controlled artificial synapse device and a preparation method thereof so as to solve the technical problem of low adjustability and accuracy of the artificial synapse device in the prior art.

(2) Technical solutions

In order to solve the above problems, the first aspect of the present invention provides a light-controlled artificial synapse device, comprising: an inert electrode; a transparent electrode; between inert electrodes, which are used to simulate synapses.

Further, the photo-memristive layer is a porous titanium oxide-doped silver nanoparticle composite film.

Further, the thickness of the inert electrode is 100±20 nm; the thickness of the photoelectric memristive layer is 900±50 nm.

Further, the silver nanoparticles in the photoelectric memristive layer are spherical and have a diameter of 11±4 nm.

According to another aspect of the present invention, there is provided a method for preparing a light-controlled artificial synapse device, comprising: S1. using a pulling method on a transparent electrode to prepare a transparent electrode with a porous titanium oxide film; S2. The transparent electrode with the porous titanium oxide film is immersed in a 0.1 mol/L silver nitrate solution under ultraviolet light irradiation to deposit silver nanoparticles to obtain a transparent electrode with a photomemristive layer; S3. An inert electrode is deposited on the side of the transparent electrode of the layer away from the transparent electrode to prepare a light-controlled artificial synapse device.

Further, the deposition of the passive electrode in step S3 adopts a thermal evaporation or sputtering process.

Further, after the pulling in step S1, the method further includes: annealing, and the annealing temperature is 450-500°C.

Further, the wavelength of the ultraviolet light irradiated by the ultraviolet light in step S2 is 365 nm, and the illumination time is 15 minutes.

Further, the aperture diameter of the metal mask used for depositing the inert electrode in step S3 is 100-500 μm, and the thickness of the electrode is 100±20 nm.

(3) Beneficial effects

The above-mentioned technical scheme of the present invention has the following beneficial technical effects:

The light-controlled artificial synapse device of the present invention can apply a positive voltage to the inert electrode, the transparent electrode is grounded, the photoelectric memristive layer forms a conductive channel under the action of the electric field, the conductance rises, and the reversible light-gating control is realized under the control of ultraviolet light and visible light. activation/inhibition. The light-controlled artificial synapse device of the present invention has a two-terminal structure, the structure is simple, the size of the device can be reduced to the nanometer level, the power consumption is small, and the reversible adjustment of the conductance variation range can be realized by means of the visible/ultraviolet light signal. Brain-like computing systems provide the device foundation. Since the multi-dimensional adjustment of light, electricity, temperature, and humidity can be realized based on the composite of common materials, it has a good application prospect in the field of new optoelectronic materials in the future.

Description of drawings

FIG. 1 is a schematic structural diagram of a light-controlled artificial synapse device according to an embodiment of the present invention.

FIG. 2 is a flowchart of a method for fabricating a light-controlled artificial synapse device according to an embodiment of the present invention.

FIG. 3 is a current-voltage curve diagram of the light-controlled artificial synapse device after being irradiated with ultraviolet light according to an embodiment of the present invention.

FIG. 4 is a current-voltage curve diagram of the light-controlled artificial synapse device after being irradiated with visible light according to an embodiment of the present invention.

FIG. 5 is a graph of the conductance change of the light-controlled artificial synapse device after being irradiated with ultraviolet light and visible light by electrical pulse stimulation according to an embodiment of the present invention.

FIG. 6 is a functional diagram of the facilitation of pulses after the light-controlled artificial synapse device is irradiated with ultraviolet light and visible light according to an embodiment of the present invention.

FIG. 7 is a functional diagram of STDP after the light-controlled artificial synapse device is irradiated with ultraviolet light and visible light according to an embodiment of the present invention.

Reference number:

1: Inert electrode; 2: Transparent electrode; 3: Photoelectric memristive layer; 31: Silver nanoparticles.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the specific embodiments and the accompanying drawings. It should be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention. Also, in the following description, descriptions of well-known structures and techniques are omitted to avoid unnecessarily obscuring the concepts of the present invention.

A schematic diagram of a layer structure according to an embodiment of the present invention is shown in the accompanying drawings. The figures are not to scale, some details are exaggerated for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the figures, as well as their relative sizes and positional relationships are only exemplary, and in practice, there may be deviations due to manufacturing tolerances or technical limitations, and those skilled in the art should Regions/layers with different shapes, sizes, relative positions can be additionally designed as desired.

Obviously, the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

The present invention will be described in more detail below with reference to the accompanying drawings. In the various figures, like elements are designated by like reference numerals. For the sake of clarity, various parts in the figures have not been drawn to scale.

FIG. 1 is a schematic structural diagram of a light-controlled artificial synapse device according to an embodiment of the present invention.

As shown in FIG. 1 , according to an embodiment of the present invention, a light-controlled artificial synapse device is provided, including: an inert electrode 1 ; a transparent electrode 2 ; a photoelectric memristive layer 3 , the photoelectric memristive layer 3 is arranged between the transparent electrode 2 and the inert electrode 1, which is used to simulate a synapse. The light-controlled artificial synapse device of the present invention can apply a positive voltage to the inert electrode, the transparent electrode is grounded, the photoelectric memristive layer forms a conductive channel under the action of the electric field, the conductance rises, and the reversible light-gating control is realized under the control of ultraviolet light and visible light. activation/inhibition. The light-controlled artificial synapse device of the present invention has a two-terminal structure, the structure is simple, the size of the device can be reduced to the nanometer level, the power consumption is small, and the reversible adjustment of the conductance variation range can be realized by means of the visible/ultraviolet light signal. Brain-like computing systems provide the device foundation. Since the multi-dimensional adjustment of light, electricity, temperature, and humidity can be realized based on the composite of common materials, it has a good application prospect in the field of new optoelectronic materials in the future.

On the basis of the original electrical signal regulation, the photomemristor layer 3 introduces an optical signal to adjust the conductance state.

The electrical characteristic function of the light-controlled artificial synapse device of the present invention is: after the visible light irradiation, the memristive characteristic of the device is activated, and the synaptic function can be simulated; after the ultraviolet light irradiation, the memristive characteristic of the device is eliminated, simulating the synapse The function disappears; the visible light and ultraviolet light operate alternately, which can realize the reversible activation and inhibition of the memristive synaptic function. The working mechanism of the device is that visible light can induce plasmon resonance of silver nanoparticles 31, promote the oxidation of silver atoms to silver ions, and make it easier to migrate under the action of an electric field, thereby activating the operation of the memristor; ultraviolet light stimulates the valence of titanium oxide With electrons, it promotes the reduction of silver ions to silver atoms and hinders the migration of silver ions, thereby inhibiting the operation of the memristor. The optical signal reversible activation and inhibition memristive synaptic device of the present invention provides a device basis for realizing an optoelectronic brain-like computing system.

In the present invention, we introduce the titanium oxide/silver material system into the light-controlled artificial synapse device. The silver nanoparticles 31 in the material undergo plasmon resonance under the action of visible light, and are oxidized into silver ions, which are easier to migrate under the action of an electric field; under the action of ultraviolet light, the electrons in the valence band of titanium oxide are excited to reduce the silver ions to atoms, and then Realize the bidirectional regulation of conductance induced by multi-band optical signal. Silver/titanium oxide nanocomposites have good application prospects in the field of new optoelectronic materials in the future because they can realize multi-dimensional adjustment of light, electricity, temperature, and humidity based on common materials.

In an optional embodiment, the photo-memristive layer 3 is a porous titanium oxide-doped silver nanoparticle composite film.

In an optional embodiment, the thickness of the passive electrode 1 is 100±20 nm; the thickness of the photo-memristive layer 3 is 900±50 nm.

In an optional embodiment, the silver nanoparticles 31 in the photo-memristive layer 3 are spherical and have a diameter of 11±4 nm.

In an optional embodiment, the number of silver nanoparticles in the porous titanium oxide-doped silver nanoparticle composite film is reduced in a first direction; the first direction is on the photoelectric memristive layer 3 . The vertical direction from the end close to the inert electrode 1 to the end close to the transparent electrode 2 .

In an optional embodiment, the transparent electrode 2 may be FTO conductive glass.

The conductive glass is SnO2 conductive glass doped with fluorine (SnO2:F), referred to as FTO for short.

In an optional embodiment, the transparent electrode 2 may be ITO conductive glass.

ITO conductive glass is made by coating a layer of indium tin oxide (commonly known as ITO) film by magnetron sputtering on the basis of soda lime base or silicon boron base glass.

In an optional embodiment, the inert electrode 1 may be an inert metal.

In an optional embodiment, the inert electrode 1 may be a metal gold electrode.

In an optional embodiment, the inert electrode 1 may be a metal platinum electrode.

The irradiation conditions of the light-controlled artificial synapse device of the present invention are as follows: the wavelength of visible light is 500-720 nm, and the irradiation time is 5-15 minutes; the wavelength of ultraviolet light is 365 nm, and the irradiation time is 5-15 minutes.

FIG. 2 is a flowchart of a method for fabricating a light-controlled artificial synapse device according to an embodiment of the present invention.

As shown in FIG. 2, according to an implementation in another embodiment of the present invention, a method for preparing a light-controlled artificial synapse device is provided, including:

S1, using the pulling method on the transparent electrode 2 to prepare the transparent electrode 2 with the porous titanium oxide film.

In an optional embodiment, the pulling in step S1 may include: stirring the titanium dioxide sol and the block copolymer PEO20-PPO70-PPO20 on the transparent electrode 2 evenly, and the transparent electrode 2 is on the surface of the transparent electrode 2 by a pulling method. A titanium oxide film is formed.

In an optional embodiment, the pulling in step S1 may further include: annealing, and the annealing temperature is 450-500°C. After annealing, the titanium oxide film on the surface of the transparent electrode 2 forms a porous structure, and the transparent electrode 2 with the porous titanium oxide film is prepared.

In an alternative embodiment, the annealing is performed at 450-500° C. for 30 minutes in an atmospheric environment. Under the regulation of high temperature, the high molecular polymer is completely decomposed to form a titanium oxide film with a porous structure.

In an optional embodiment, step S1 may further include: cleaning, using trichloroethylene, acetone, ethanol, and secondary deionized water in order to ultrasonicate the transparent electrode 2 in an ultrasonic cleaning machine for 10 minutes to remove dust on the surface of the substrate , grease and other impurities, and blow dry.

In an optional embodiment, the pulling in step S1 may include: stirring the titanium dioxide sol and the block copolymer PEO20-PPO70-PPO20 on the cleaned transparent electrode 2 evenly, 2 A layer of titanium oxide film is formed on the surface.

In an optional embodiment, the drying adopts air, and the drying is performed by an air compressor.

In an optional embodiment, nitrogen gas is used for the blow-drying.

S2. The transparent electrode 2 with the porous titanium oxide film is immersed in a 0.1 mol/L silver nitrate solution under ultraviolet light irradiation to deposit silver nanoparticles 31 to prepare a transparent electrode 2 with a photomemristive layer 3 .

In an optional embodiment, the wavelength of the ultraviolet light irradiated by the ultraviolet light in step S2 is 365 nm, and the illumination time is 15 minutes.

In an optional embodiment, in step S2, the silver nanoparticles 31 are immersed in a 0.1 mol/L silver nitrate solution under ultraviolet light irradiation to deposit silver nanoparticles 31, and after the reduction is completed, the silver nanoparticles 31 are rinsed with deionized water and dried to obtain a photoelectric memristive layer. 3 transparent electrodes 2.

S3, depositing an inert electrode 1 on the side of the transparent electrode 2 with the photo-memristive layer 3 away from the transparent electrode 2 to prepare a photo-controlled artificial synapse device.

In an optional embodiment, the deposition of the passive electrode 1 in step S3 adopts a thermal evaporation or sputtering process.

In an optional embodiment, the aperture diameter of the metal mask used for depositing the passive electrode 1 in step S3 is 100-500 μm, and the electrode thickness is 100±20 nm.

In the preparation method of the light-controlled artificial synapse device of the present invention, the silver particles deposited in the porous titanium oxide film by means of ultraviolet light have photo-induced redox properties. Under the action of visible light, silver nanoparticles undergo plasmon resonance, and silver atoms are oxidized into silver ions; under the action of ultraviolet light, electrons in the valence band of titanium oxide are excited to reduce silver ions into silver atoms. Among them, the thickness of the silver/titanium oxide film is 900±50 nm, and the silver particles in the film are spherical and have a diameter of 11±4 nm.

FIG. 3 is a current-voltage curve diagram of the light-controlled artificial synapse device after being irradiated with ultraviolet light according to an embodiment of the present invention.

FIG. 4 is a current-voltage curve diagram of the light-controlled artificial synapse device after being irradiated with visible light according to an embodiment of the present invention.

Electrical test: Figures 3 and 4 show the memristive properties (current-voltage) of the light-controlled artificial synapse device after irradiation with ultraviolet light (365 nm) and visible light (500-720 nm).

As shown in Figure 3, for the device irradiated by ultraviolet light for 15 minutes, the conductance of the device will not change with positive and negative voltage sweeps, and the conductance of the device does not change regularly under continuous positive or negative voltage sweeps. .

As shown in Fig. 4, for the light-controlled artificial synapse device irradiated with visible light for 15 minutes, the resistive-switching behavior with continuous resistance change appeared under the same voltage sweep. Under the continuous positive voltage sweep, the device conductance kept rising; under the continuous negative voltage sweep, the device conductance kept decreasing.

FIG. 5 is a graph of the conductance change of the light-controlled artificial synapse device after being irradiated with ultraviolet light and visible light by electrical pulse stimulation according to an embodiment of the present invention.

Figure 5 shows the response of the light-controlled artificial synapse device to specific electrical signal stimulation after being sequentially modulated by visible light (500-720 nm) and ultraviolet light (365 nm). The initial device (ie, the photo-controlled artificial synapse device after UV reduction) did not change significantly in conductance under five consecutive electrical pulses (0.5 V, 100 μs). After being irradiated with visible light and stimulated by the same electrical pulse, the conductance of the device increased significantly, and there was an obvious facilitation phenomenon between the pulses. After the device was irradiated with ultraviolet light again, under the same pulse stimulation, the response amplitude became smaller, and quickly returned to the initial state after the pulse stimulation.

FIG. 6 is a functional diagram of the facilitation of pulses after the light-controlled artificial synapse device is irradiated with ultraviolet light and visible light according to an embodiment of the present invention.

Figure 6 shows the pulse facilitation phenomenon of the light-controlled artificial synapse device in the initial state and after 5/10/15 minutes of visible light irradiation. Under the same conditions, the longer the visible light irradiation time, the more obvious the facilitation effect between adjacent pulses, that is, the greater the change in PPF.

FIG. 7 is a functional diagram of STDP after the light-controlled artificial synapse device is irradiated with ultraviolet light and visible light according to an embodiment of the present invention.

Figure 7 presents the results of simulating the learning rule of pulse time-dependent synaptic plasticity (STDP) in the light-controlled artificial synapse device. index relationship. The enhancement/suppression effect increases as the time difference decreases. And under the same conditions, the longer the visible light irradiation time, the more obvious the synaptic weight change.

STDP is the abbreviation of Spike Timing Dependnt Plasticity. (Synaptic device) plasticity based on sequential discharge, or timing dependent plasticity, is one of the synaptic learning rules discovered in experimental biology.

The present invention aims to protect a light-controlled artificial synapse device and a preparation method thereof. The light-controlled artificial synapse device comprises: an inert electrode 1; a transparent electrode 2; Between the transparent electrode 2 and the inert electrode 1, it is used to simulate a synapse. The light-controlled artificial synapse device of the present invention can apply a positive voltage to the inert electrode, the transparent electrode is grounded, the photoelectric memristive layer forms a conductive channel under the action of the electric field, the conductance rises, and the reversible light-gating control is realized under the control of ultraviolet light and visible light. activate/inhibit. The light-controlled artificial synapse device of the present invention has a two-terminal structure, the structure is simple, the size of the device can be reduced to the nanometer level, the power consumption is small, and the reversible adjustment of the conductance variation range can be realized by means of the visible/ultraviolet light signal. Brain-like computing systems provide the device foundation. Since the multi-dimensional adjustment of light, electricity, temperature, and humidity can be realized based on the composite of common materials, it has a good application prospect in the field of new optoelectronic materials in the future.

It should be understood that the above-mentioned specific embodiments of the present invention are only used to illustrate or explain the principle of the present invention, but not to limit the present invention. Therefore, any modifications, equivalent replacements, improvements, etc. made without departing from the spirit and scope of the present invention should be included within the protection scope of the present invention. Furthermore, the appended claims of this invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalents of such scope and boundaries.

Claims (9)

1. a light-controlled artificial synapse device, is characterized in that, comprises: inert electrode (1); transparent electrode (2); A photo memristive layer (3), the photo memristive layer (3) is arranged between the transparent electrode (2) and the inert electrode (1), which is used for simulating a synapse. 2. The light-controlled artificial synapse device according to claim 1, characterized in that, The photo-memristive layer (3) is a porous titanium oxide-doped silver nanoparticle composite film. 3. The light-controlled artificial synapse device according to claim 4, wherein The thickness of the inert electrode (1) is 100±20nm; The thickness of the photo-memristive layer (3) is 900±50 nm. 4. The light-controlled artificial synapse device according to claim 2, wherein The silver nanoparticles (31) in the photoelectric memristive layer (3) are spherical and have a diameter of 11±4 nm. 5. A preparation method of a light-controlled artificial synapse device, characterized in that, comprising: S1, using the pulling method on the transparent electrode (2) to obtain a transparent electrode (2) with a porous titanium oxide film; S2. The transparent electrode (2) with the porous titanium oxide film is immersed in a 0.1 mol/L silver nitrate solution under ultraviolet light irradiation to deposit silver nanoparticles (31) to obtain a photomemristive layer (3). ) of the transparent electrode (2); S3, depositing an inert electrode (1) on the side of the transparent electrode (2) with the photoelectric memristive layer (3) away from the transparent electrode (2) to prepare a photo-controlled artificial synapse device. 6. The preparation method of the light-controlled artificial synapse device according to claim 5, wherein, The deposition of the inert electrode (1) in step S3 adopts a thermal evaporation or sputtering process. 7. The method for preparing a light-controlled artificial synapse device according to claim 5, characterized in that, after pulling in step S1, the method further comprises: Annealing, the annealing temperature is 450-500 ℃. 8. The preparation method of the light-controlled artificial synapse device according to claim 5, wherein, In step S2, the wavelength of the ultraviolet light irradiated by the ultraviolet light is 365 nm, and the irradiation time is 15 minutes. 9. The preparation method of the light-controlled artificial synapse device according to claim 5, wherein, In step S3, the diameter of the metal mask used for depositing the inert electrode (1) is 100-500 μm, and the thickness of the electrode is 100±20 nm.

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