Solar-blind ultraviolet photoelectric artificial visual synaptic device based on aluminum-yttrium-nitrogen thin film and preparation method of solar-blind ultraviolet photoelectric artificial visual synaptic device

Abstract

The invention discloses a solar-blind ultraviolet photoelectric artificial visual synaptic device based on an aluminum-yttrium-nitrogen thin film and a preparation method of the solar-blind ultraviolet photoelectric artificial visual synaptic device, and relates to the field of novel micro-nano electronic materials and functional devices. The synaptic device comprises a substrate, a bottom electrode, a solar blind ultraviolet light response resistive layer and a top electrode, the bottom electrode is arranged on the substrate and is used for introducing a solar blind ultraviolet light signal; the solar blind ultraviolet light response resistive layer is arranged between the bottom electrode and the top electrode and used for simulating synaptic plasticity. Wherein the solar-blind ultraviolet light response resistance change layer is made of an aluminum-yttrium-nitrogen film with a photoconductive effect, and has photoresponse to solar-blind ultraviolet light with the wavelength of 200-280nm; the bottom electrode is a transparent conductive electrode; an electric signal is input through the top electrode and the bottom electrode, and a solar blind ultraviolet light signal is input through the transparent conductive bottom electrode; the synaptic device provided by the invention can realize various photoelectric synaptic plasticity under the excitation of an electric signal and a solar-blind ultraviolet light signal, so that the simulation of an artificial visual function is realized on the basis of the synaptic device.

Description

Technical Field

[0001] The present invention relates to the technical field of microelectronic devices, and in particular to a solar-blind ultraviolet photoelectric artificial visual synapse device based on an aluminum yttrium nitrogen thin film and a preparation method thereof. Background Art

[0002] The human brain, comprised of a vast neural network composed of numerous neurons and synapses, possesses a highly sought-after, efficient, and power-efficient integrated storage and computing architecture. Vision, one of the most crucial functional systems in the human brain, helps humans receive information from the outside world. Over 80% of external information is received through the human visual system. Cones on the retina enable us to distinguish the different wavelengths and intensities of visible light (390-780nm), converting light stimuli into nerve impulses that are transmitted through synapses to the brain for further processing, enabling perception, learning, and memory. Researchers have discovered that brain-inspired computing, a new generation of artificial intelligence technology, can mimic the structure and function of the human brain while simultaneously processing, storing, and transmitting information. To emulate the human visual system, researchers have combined traditional brain-inspired synaptic devices with the optical signal response capabilities of photodetectors to create artificial photoelectric synaptic devices. Based on multiple basic synaptic functions, they have successfully achieved the perception, learning, and memory of information data under photoelectric signal modulation.

[0003] Due to the addition of light signals, optoelectronic synaptic devices not only avoid the problems of traditional electronic synaptic devices such as poor stability, large write noise, and difficulty in controlling the growth of conductive filaments, but also expand the application of synaptic devices to the fields of visual perception and visual memory, and have attracted widespread attention from researchers.

[0004] However, current optoelectronic synaptic devices mostly focus on the memristive effect and photoelectric response characteristics, with little research on photoselectivity. The optical modulation wavelength range is in the near-ultraviolet, visible, and infrared regions. The optical modulation behavior within this wavelength range is susceptible to interference from background sunlight, and optical modulation devices based on this wavelength range lack the ability to resist optical signal interference. Therefore, there is an urgent need to develop a light source with strong interference immunity for use in optically modulated synaptic memristive devices. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to propose a solar-blind ultraviolet photoelectric artificial visual synapse device based on aluminum yttrium nitrogen thin film and a preparation method thereof, so as to solve the problem that current photoelectric synapse devices are easily affected by solar background light noise in practical applications.

[0006] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0007] A solar-blind ultraviolet photoelectric artificial visual synaptic device based on aluminum yttrium nitride thin film. The device achieves multiple light-variable synaptic plasticities under the stimulation of electrical signals and / or solar-blind ultraviolet light signals. This scheme simulates artificial visual functions on this basis. In this scheme, the device includes a substrate, a bottom electrode, a solar-blind ultraviolet light-responsive resistive layer, and a top electrode, which are stacked in sequence.

[0008] The bottom electrode is used to introduce a solar-blinding ultraviolet light signal, and the solar-blinding ultraviolet light-responsive resistive layer is used to simulate synaptic plasticity, and has a light response to solar-blinding ultraviolet light with a wavelength of 200-280 nm.

[0009] As a possible implementation method, further, the day-blind ultraviolet light responsive resistive switching layer described in this scheme is composed of a double-layer aluminum yttrium nitrogen film, wherein one aluminum yttrium nitrogen film is in contact with the top electrode, which is used to accumulate migrating ions, and the other aluminum yttrium nitrogen film serves as a resistive switching layer, which is used to promote the stable and orderly migration of ions to form conductive filaments.

[0010] As a preferred embodiment, preferably, in the double-layer aluminum yttrium nitride film of this scheme, the aluminum yttrium nitride film in contact with the top electrode is an oxygen-deficient aluminum yttrium nitride film grown in a composite atmosphere of argon and nitrogen, and its thickness is 30-40nm; the other aluminum yttrium nitride film is an oxygen-rich aluminum yttrium nitride film grown in a composite atmosphere of nitrogen, argon and oxygen, which is arranged on the bottom electrode and has a thickness of 65-75nm.

[0011] As a possible implementation manner, further, the substrate described in this solution is a transparent substrate, and the transparent substrate includes a sapphire substrate; the bottom electrode is made of a transparent conductive electrode, and the transparent conductive electrode includes an ITO electrode, and the thickness of the bottom electrode is 40-80nm.

[0012] As a possible embodiment, the top electrode in this embodiment is made of nickel and has a thickness of 50-100 nm. In this embodiment, if the top electrode thickness exceeds the range of 50-100 nm, it will significantly affect the overall performance of the present invention, including the magnitude of the generated photocurrent, the number of cycles, and the ability of the simulated synapse to "learn" and "forget."

[0013] Based on the above, this solution also proposes a method for preparing a solar-blind ultraviolet photoelectric artificial visual synapse device based on aluminum yttrium nitrogen thin film, which includes the following steps:

[0014] 1) growing an ITO bottom electrode on a substrate;

[0015] 2) growing an oxygen-rich aluminum yttrium nitride film on the bottom electrode, and then growing an oxygen-deficient aluminum yttrium nitride film on the oxygen-rich aluminum yttrium nitride film, the two forming a solar-blind ultraviolet light responsive resistive switching layer;

[0016] 3) Growing a top electrode on the solar-blind ultraviolet light-responsive resistive switching layer to obtain the solar-blind ultraviolet photoelectric artificial visual synapse device.

[0017] As a possible implementation method, further, the growth methods in step 1) and step 2) of this solution both adopt magnetron sputtering technology, and the growth method in step 3) adopts ultra-vacuum thermal evaporation technology.

[0018] As a possible implementation, further, step 1) of this solution includes the following:

[0019] Install the ITO target on the magnetron target position, and place the cleaned, dried and pre-treated sapphire substrate on the substrate tray in the magnetron sputtering chamber, ensuring that the substrate is completely in contact with the bottom of the substrate and there is no foreign matter;

[0020] Pump the pressure in the sputtering chamber to 5×10 -4 Pa, then argon was filled into the sputtering chamber at a flow rate of 20 sccm, and the high valve was adjusted to keep the internal air pressure at 1 Pa. When the air pressure was stable, the sputtering power was adjusted to 105 W. After pre-sputtering for 5 minutes, the baffle was opened and sputtering was continued for 1 minute. Finally, the ITO bottom electrode was obtained.

[0021] In this scheme, as an example, the substrate is sapphire, which needs to be pretreated. The specific steps are: immerse the sapphire substrate in acetone, alcohol and deionized water solution in turn, and use ultrasonic equipment to clean it for 15 minutes, a round of 45 minutes in total, and repeat three rounds to fully remove stains on the surface of the substrate. Then, heat and dry the substrate and store it for future use.

[0022] As a possible implementation, further, step 2) of this solution includes the following:

[0023] Install the aluminum target and the yttrium target on the target position of the magnetron, and place the sapphire substrate with the ITO bottom electrode prepared in step 1) on the substrate tray in the magnetron sputtering chamber, ensuring that the substrate is completely in contact with the bottom of the substrate and there is no foreign matter;

[0024] Cut the tin foil into appropriate size, place it close to the surface of part of the ITO bottom electrode, and stick the edge of the tin foil to the substrate tray with tape;

[0025] Pump the pressure in the sputtering chamber to 5×10 -4 After the pressure reaches 1 Pa, high-purity argon (99.999%) and high-purity nitrogen (99.999%) are charged into the sputtering chamber at a flow rate of 20 sccm, and high-purity oxygen (99.999%) is charged into the sputtering chamber at a flow rate of 15 sccm. The high valve is then adjusted to maintain the internal pressure at 1 Pa. When the pressure stabilizes, the two sputtering powers are adjusted to 100 W. After pre-sputtering for 5 minutes, the baffle is opened and the formal sputtering is carried out for 15 minutes. Finally, an oxygen-rich aluminum yttrium nitrogen film is obtained.

[0026] After the sputtering time for obtaining the oxygen-rich aluminum yttrium nitrogen film is reached, the film sputtering is stopped, and the introduction of nitrogen, argon and oxygen gases is suspended, and the process is continued for 20 minutes; after 20 minutes, high-purity argon (99.999%) and high-purity nitrogen (99.999%) are again filled into the sputtering chamber at a flow rate of 20 sccm, and the high valve is adjusted to maintain the internal air pressure at 1 Pa. When the air pressure is stable, the two sputtering powers are adjusted to 100 W. After pre-sputtering for 5 minutes, the baffle is opened and formal sputtering is carried out for 15 minutes to obtain the oxygen-deficient aluminum yttrium nitrogen film; the oxygen-rich aluminum yttrium nitrogen film and the oxygen-deficient aluminum yttrium nitrogen film constitute a day-blind ultraviolet light responsive resistive switching layer.

[0027] As a possible implementation, further, step 3) of this solution includes the following:

[0028] Nickel metal particles are placed in a tungsten boat, and ultra-high vacuum evaporation coating equipment is used to evaporate a metal nickel electrode on the surface of the aluminum yttrium nitrogen day-blind ultraviolet light responsive resistive layer using a circular hole mask with a diameter of 500 μm. The thickness of the nickel electrode is 100 nm.

[0029] In this scheme, steps 1) to 3) can all be performed at room temperature.

[0030] In this scheme, the wavelength band of solar-blind ultraviolet light is 200-280nm. Solar radiation in this band is almost completely absorbed by the Earth's ozone layer, and the background radiation in this band in the atmosphere is almost zero. This provides a good communication background for optical communication systems operating in this band. Therefore, photodetectors based on solar-blind ultraviolet light are often used as prototype optical communication devices. Furthermore, solar-blind ultraviolet light offers advantages such as high confidentiality, strong environmental adaptability, high flexibility and reliability, and all-weather operation. It is widely used in military and civilian fields such as missile tracking, fire warning, and deep space exploration. As can be seen, optical modulation behavior within the solar-blind ultraviolet band will have extremely low background noise. In the solar-blind ultraviolet optoelectronic artificial visual synapse device based on aluminum yttrium nitride thin film provided in this scheme, the solar-blind ultraviolet light-responsive resistive switching layer based on the aluminum yttrium nitride thin film exhibits a significant positive photoresponse to solar-blind ultraviolet light with a wavelength of 200-280nm. This addresses the problem that the optical modulation signals of most current optoelectronic synapse devices are susceptible to solar background noise.

[0031] By adopting the above-mentioned technical solution, the present invention has the following beneficial effects compared with the prior art: the day-blind ultraviolet photoelectric artificial visual synaptic device of the present invention can realize a variety of synaptic plasticity under the modulation of electric pulses and day-blind ultraviolet light pulses. Under the joint modulation of photoelectric pulses, not only can light enhancement and electrical erasure behaviors be realized, but also a variety of advanced synaptic neuromorphic functions including short-term and long-term memory, learning-forgetting-relearning can be successfully simulated. In addition, under the stimulation of day-blind ultraviolet light, the photoelectric synaptic device exhibits strong "learning and memory" capabilities, realizing human visual perception and memory functions. More importantly, the output current signal of the device does not change at all under the interference of light signals (white light), which ensures the security of information transmission. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 This is a schematic structural diagram of a day-blind ultraviolet photoelectric artificial visual synapse device provided by an embodiment of the present invention; in Figure 1, the reference numbers refer to: 1, substrate; 2, bottom electrode; 3, day-blind ultraviolet light-responsive resistive layer; 4, top electrode; 31, oxygen-rich aluminum yttrium nitride film; 32, oxygen-deficient aluminum yttrium nitride film.

[0034] Figure 2 This is a physical picture of the solar-blind ultraviolet photoelectric artificial visual synapse device provided by an embodiment of the present invention.

[0035] Figure 3 This is a cross-sectional SEM image of an ITO bottom electrode provided by an embodiment of the present invention.

[0036] Figure 4 This is an absorption spectrum of the aluminum yttrium nitrogen solar-blind ultraviolet light responsive resistive layer provided by one embodiment of the present invention.

[0037] Figure 5 This is a transmission spectrum diagram of the ITO bottom electrode provided by an embodiment of the present invention.

[0038] Figure 6 This is a memristor IV test curve of the solar-blind ultraviolet photoelectric artificial visual synapse device provided by an embodiment of the present invention under the action of a positive electrical signal.

[0039] Figure 7 This is a memristor IV test curve of the day-blind ultraviolet photoelectric artificial visual synapse device provided by an embodiment of the present invention under the action of a reverse electrical signal.

[0040] Figure 8 This is a memristor IV test curve of the solar-blind ultraviolet photoelectric artificial visual synapse device provided by an embodiment of the present invention under the action of a solar-blind ultraviolet light signal.

[0041] Figure 9 The solar-blind ultraviolet photoelectric artificial visual synapse device provided in one embodiment of the present invention realizes light enhancement and electrical erasure behavior under the joint modulation of photoelectric pulses.

[0042] Figure 10 This is the device conductance of the day-blind ultraviolet photoelectric artificial visual synapse device provided by an embodiment of the present invention under the action of continuous day-blind ultraviolet light pulses.

[0043] Figure 11 The solar-blind ultraviolet photoelectric artificial visual synapse device provided in one embodiment of the present invention simulates the learning-forgetting-relearning process.

[0044] Figure 12 The solar-blind ultraviolet photoelectric artificial visual synapse device array provided in one embodiment of the present invention simulates visual perception and memory functions under solar-blind ultraviolet light. DETAILED DESCRIPTION

[0045] The present invention will be described in further detail below with reference to the accompanying drawings and examples. It is particularly noted that the following examples are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. Similarly, the following examples are only some embodiments of the present invention and are not intended to be exhaustive. All other embodiments obtained by those of ordinary skill in the art without creative effort are intended to fall within the scope of protection of the present invention.

[0046] refer to Figure 1 As shown, this embodiment provides a day-blind ultraviolet photoelectric artificial visual synapse device based on aluminum yttrium nitride thin film, which can achieve multiple photoelectric synaptic plasticities under the stimulation of electrical signals and day-blind ultraviolet light signals, and on this basis realize the simulation of artificial visual functions.

[0047] Structurally, the solar-blind ultraviolet photoelectric artificial visual synapse device based on aluminum yttrium nitride thin film in this scheme includes: a substrate 1, a bottom electrode 2, a solar-blind ultraviolet light-responsive resistive layer 3 and a top electrode 4.

[0048] Among them, the bottom electrode 2 is arranged on the substrate 1, which is a transparent conductive electrode for introducing day-blind ultraviolet light signals; the day-blind ultraviolet light response resistive layer 3 is arranged between the bottom electrode 2 and the top electrode 4, for simulating synaptic plasticity, and has a positive light response to day-blind ultraviolet light with a wavelength of 200-280nm.

[0049] The substrate 1 of this embodiment is a sapphire substrate, which may also be other transparent substrates; the bottom electrode 2 may be made of an ITO electrode or other transparent conductive electrodes, and the thickness of the bottom electrode 2 is 40-80 nm.

[0050] In this embodiment, the solar-blind ultraviolet light-responsive resistive layer 3 is a double-layer aluminum yttrium nitride film, wherein one layer of the double-layer aluminum yttrium nitride film close to the top electrode is an oxygen-deficient aluminum yttrium nitride film grown in a composite atmosphere of argon and nitrogen, with a thickness of 30-40 nm; the other layer is an oxygen-rich aluminum yttrium nitride film grown in a composite atmosphere of argon, nitrogen and oxygen, with a thickness of 65-75 nm, and is arranged on the bottom electrode 2.

[0051] The top electrode is made of metal nickel, and the thickness of the top electrode is 50-100 nm.

[0052] If the thickness of the top electrode 4 exceeds the range of 50-100 nm, it will have a significant impact on the overall performance of this solution, including: the size of the generated photocurrent, the number of cycles, and the "learning" and "forgetting" capabilities of the simulated synapse, etc.

[0053] Based on the above, this embodiment further provides a method for preparing a solar-blind ultraviolet photoelectric artificial visual synapse device based on an aluminum yttrium nitride thin film, which comprises the following steps:

[0054] 1) growing an ITO bottom electrode on a substrate;

[0055] 2) growing an oxygen-rich aluminum yttrium nitrogen film on the bottom electrode;

[0056] 3) growing an oxygen-deficient aluminum yttrium nitride film on an oxygen-rich aluminum yttrium nitride film;

[0057] 4) Growing a top electrode on the solar-blind ultraviolet light-responsive resistive switching layer to obtain the solar-blind ultraviolet photoelectric artificial visual synapse device.

[0058] Refer to the attached Figure 1 As shown, the aluminum-yttrium-nitride thin film-based solar-blind ultraviolet optoelectronic artificial visual synaptic device fabricated using the method of this embodiment comprises, from top to bottom, a metal nickel electrode, an aluminum-yttrium-nitride thin film, an ITO bottom electrode, and a sapphire substrate. The protruding device of this embodiment, stimulated by electrical signals and solar-blind ultraviolet light signals, achieves various optoelectronic synaptic plasticity, thereby simulating artificial visual functions.

[0059] The solar-blind ultraviolet photoelectric artificial visual synapse device in this embodiment can be prepared by the following method:

[0060] (1) Soak the sapphire substrate in acetone, alcohol, and deionized water solution in turn, and use ultrasonic equipment to clean it for 15 minutes. One round lasts for 45 minutes. Repeat three rounds to fully remove stains on the substrate surface. Then heat and dry the substrate and store it for future use.

[0061] (2) Install the ITO target on the magnetron target position, and place the sapphire substrate obtained in step (1) on the substrate tray in the magnetron sputtering chamber, ensuring that the substrate is completely in contact with the bottom of the substrate and there is no foreign matter. Pump the air pressure in the sputtering chamber to 5×10 - 4 Pa, then argon was filled into the sputtering chamber at a flow rate of 20 sccm, and the high valve was adjusted to maintain the internal pressure at 1 Pa. When the pressure stabilized, the RF control panel was turned on. The sputtering power was adjusted to 105W, and after pre-sputtering for 5 minutes, the baffle was opened and sputtering was continued for 1 minute to finally obtain the ITO bottom electrode.

[0062] (3) Install the aluminum target and yttrium target on the target position of the magnetron, and place the sapphire substrate with the ITO bottom electrode grown in step 1) on the substrate tray in the magnetron sputtering chamber, ensuring that the substrate is completely in contact with the bottom of the substrate and free of foreign matter. Cut the tin foil to a suitable size, adhere it to part of the surface of the ITO bottom electrode, and stick the edge of the tin foil to the substrate tray with tape. Pump the air pressure in the sputtering chamber to 5×10 -4 After Pa, high-purity argon (99.999%) and high-purity nitrogen (99.999%) are filled into the sputtering chamber at a flow rate of 20sccm, and high-purity oxygen (99.999%) is filled into the sputtering chamber at a flow rate of 15sccm, and then the high valve is adjusted to keep the internal air pressure at 1Pa. When the air pressure stabilizes, turn on the RF control panel. Adjust the two sputtering powers to 100W, open the baffle after 5 minutes of pre-sputtering, and officially sputter for 15 minutes, and finally obtain the first layer of aluminum yttrium nitrogen film (oxygen-rich aluminum yttrium nitrogen film). After the sputtering time is reached, quickly close the baffle and stop film sputtering. At the same time, suspend the introduction of nitrogen, argon and oxygen gases and wait for 20 minutes. After 20 minutes, high-purity argon (99.999%) and high-purity nitrogen (99.999%) were again introduced into the sputtering chamber at a flow rate of 20 sccm. The high pressure valve was then adjusted to maintain the internal pressure at 1 Pa. When the pressure stabilized, the RF control panel was turned on. Both sputtering powers were adjusted to 100 W. After 5 minutes of pre-sputtering, the baffle was opened and the main sputtering process was continued for 15 minutes, finally obtaining the second layer of aluminum yttrium nitride film (oxygen-deficient aluminum yttrium nitride film).

[0063] (4) Nickel metal particles are placed in a tungsten boat, and a metal nickel electrode is evaporated on the surface of the aluminum yttrium nitrogen day-blind ultraviolet light responsive resistive layer obtained in step (3) using an ultra-high vacuum evaporation coating device using a circular hole mask with a diameter of 500 μm, wherein the thickness of the nickel electrode is 100 nm.

[0064] Steps (1) to (4) in the preparation method provided in this embodiment can all be performed at room temperature.

[0065] Combine Figure 2 As shown, it shows a physical picture of a solar-blind ultraviolet photoelectric artificial visual synapse device based on aluminum yttrium nitrogen film provided in an embodiment of this solution. The cross-sectional SEM image of the ITO bottom electrode provided in this embodiment of the solution is as follows: Figure 3 shown.

[0066] Figure 4 The figure shows the absorption spectrum of the aluminum yttrium nitrogen solar-blind ultraviolet light-responsive resistive switching layer provided in this embodiment. It can be seen that the aluminum yttrium nitrogen solar-blind ultraviolet light-responsive resistive switching layer in this embodiment has significant light absorption for solar-blind ultraviolet light with a wavelength of 200-280nm, while weak light absorption for light with a wavelength of 280nm-800nm, indicating that the light modulation signal of the synaptic device in this embodiment is indeed not easily affected by the background light noise of the sun and has a certain anti-interference ability. Since the present invention adopts bottom illumination, in order to eliminate the possible influence of the presence of the bottom electrode on the absorption effect of the aluminum yttrium nitrogen film on solar-blind ultraviolet light, the transmission spectrum of the ITO bottom electrode was tested. The test results are shown in FIG. Figure 5 As shown, the transmission curve results of the bottom electrode show that the transmittance of ITO under 255nm solar-blind ultraviolet light is as high as 72.64%, which means that the solar-blind ultraviolet light can be fully absorbed by the aluminum yttrium nitrogen film.

[0067] Figure 6 and Figure 7 The following are the memristor IV test curves of the day-blind ultraviolet optoelectronic artificial vision synaptic device provided by this embodiment under the action of forward and reverse electrical signals. 20 cycles of forward sweep voltage (0→5→0V) and reverse sweep voltage (0→-5→0V) were applied continuously to the synaptic device. It can be observed that under the action of the forward sweep voltage in the first cycle, the device's conductance at 5→0V is generally greater than that at 0→5V. Similarly, under the action of the reverse sweep voltage in the first cycle, the device's conductance at -5→0V is generally smaller than that at 0→-5V. In addition, under a series of forward and reverse sweep voltages, as the number of sweep cycles increases, the device's conductance gradually increases under the application of the forward sweep voltage and gradually decreases under the application of the reverse sweep voltage.

[0068] Figure 8 The memristor IV test curve of the solar-blind ultraviolet photoelectric artificial visual synaptic device provided in this embodiment under the action of solar-blind ultraviolet light signal is shown in Figure 2. ... 2) under day-blinding ultraviolet light pulses, the conductance of the synaptic device increased with the increase of light intensity, had a good positive response to day-blinding ultraviolet light, and maintained a high memory level after the light pulse was withdrawn.

[0069] Figure 9 The solar-blind ultraviolet photoelectric artificial visual synaptic device provided in this embodiment realizes light enhancement and electrical erasure under the co-modulation of photoelectric pulses. 2 The current under irradiation of 255nm day-blind ultraviolet light pulse with a pulse width of 5s is significantly enhanced, and the corresponding conductance of the synaptic device gradually increases. Under the action of the reverse voltage pulse (pulse amplitude: -5V, pulse width: 5s), the current decreases rapidly, and the conductance returns to the level before light irradiation, achieving electrical erasure, and the reading voltage is: 0.05V.

[0070] Figure 10 The device conductivity of the day-blind ultraviolet photoelectric artificial visual synaptic device provided in this embodiment is under the action of continuous day-blind ultraviolet light pulses. The inset is a partial enlarged view (light intensity: 2.93mW / cm 2 , pulse width: 5s, interval: 5s). As shown in the figure, the conductance of the synaptic device rises rapidly under continuous light pulse illumination and maintains good conductance for at least 300s after the light pulse is removed. Furthermore, this data demonstrates the high reproducibility of the synaptic device in light-induced tunable synaptic behavior.

[0071] The above results show that the device can be transformed from short-term memory to long-term memory by changing the number of light pulse irradiations and the light intensity.

[0072] Figure 11 The day-blind ultraviolet optoelectronic artificial visual synaptic device provided in this embodiment simulates the learning-forgetting-relearning process. It can be seen that the device's "memory" level is significantly improved after every 1 second of "learning," and slightly decreases during the 10 seconds of "forgetting." After each "learning-forgetting" cycle, the device's "memory" level is better than the previous one. The device's "memory" level after five cycles (ΔI5) is 5.625 times higher than the "memory" level after the first cycle (ΔI1).

[0073] Figure 12 The solar-blind ultraviolet optoelectronic artificial visual synaptic device array provided in this embodiment simulates visual perception and memory functions under solar-blind ultraviolet light. Solar-blind ultraviolet light is transmitted through a mask printed with a "double F" shape, irradiating the 5×5 array from the bottom. The light intensity of the large F is 3.95mW / cm 2 The light intensity of small F is 3.54mW / cm 2The light intensity of the remaining part not directly exposed to the solar-blinding ultraviolet light is 2.93mW / cm 2 After the device array was no longer illuminated, the photocurrent response of the array was read at 0s, 5s, and 10s, with a reading voltage of 0.05V. As can be seen from the figure, the "double F" image was clearly perceived, and the photocurrent response decreased slightly over time, but it could still be remembered after 10s. This result indicates that the device array has the potential to simulate human visual perception and persistent memory functions under day-blind ultraviolet light signals.

[0074] The above descriptions are only some embodiments of the present invention and do not limit the scope of protection of the present invention. Any equivalent device or equivalent process transformation made by using the contents of the description and drawings of the present invention, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A solar-blind ultraviolet optoelectronic artificial visual synapse device based on aluminum yttrium nitrogen film, characterized in that: The device realizes multiple light-variable synaptic plasticity under the stimulation of electrical signals and / or solar-blind ultraviolet light signals; The device comprises a substrate, a bottom electrode, a solar-blind ultraviolet light-responsive resistive switching layer and a top electrode which are stacked in sequence; The bottom electrode is used to introduce a solar-blind ultraviolet light signal, and the solar-blind ultraviolet light-responsive resistive layer is used to simulate synaptic plasticity, and has a light response to solar-blind ultraviolet light with a wavelength of 200-280 nm.

2. The solar-blind ultraviolet optoelectronic artificial visual synapse device based on aluminum yttrium nitrogen film according to claim 1, characterized in that: The solar-blind ultraviolet light responsive resistive layer is composed of a double-layer aluminum yttrium nitride film, one of which is in contact with the top electrode and is used to accumulate migrating ions, and the other aluminum yttrium nitride film serves as a resistive layer and is used to promote stable and orderly migration of ions to form conductive filaments.

3. The solar-blind ultraviolet optoelectronic artificial visual synapse device based on aluminum yttrium nitrogen film according to claim 2, characterized in that: In the double-layer aluminum yttrium nitride film, the aluminum yttrium nitride film in contact with the top electrode is an oxygen-deficient aluminum yttrium nitride film grown in a composite atmosphere of argon and nitrogen, and its thickness is 30-40nm; the other aluminum yttrium nitride film is an oxygen-rich aluminum yttrium nitride film grown in a composite atmosphere of nitrogen, argon and oxygen, which is arranged on the bottom electrode and has a thickness of 65-75nm.

4. The solar-blind ultraviolet optoelectronic artificial visual synapse device based on aluminum yttrium nitride film according to claim 1, characterized in that: The substrate is a transparent substrate, and the transparent substrate includes a sapphire substrate; the bottom electrode is made of a transparent conductive electrode, and the transparent conductive electrode includes an ITO electrode, and the thickness of the bottom electrode is 40-80 nm.

5. The solar-blind ultraviolet optoelectronic artificial visual synapse device based on aluminum yttrium nitride film according to claim 1, characterized in that: The top electrode is made of metal nickel and has a thickness of 50-100 nm.

6. A method for preparing a solar-blind ultraviolet optoelectronic artificial visual synapse device based on aluminum yttrium nitrogen film, characterized in that: The steps include: 1) Growing an ITO bottom electrode on a substrate; 2) growing an oxygen-rich aluminum yttrium nitride film on the bottom electrode, and then growing an oxygen-deficient aluminum yttrium nitride film on the oxygen-rich aluminum yttrium nitride film, the two forming a solar-blind ultraviolet light responsive resistive switching layer; 3) Growing a top electrode on the solar-blind ultraviolet light-responsive resistive layer to obtain the solar-blind ultraviolet photoelectric artificial visual synapse device.

7. The method for preparing a solar-blind ultraviolet optoelectronic artificial visual synapse device based on aluminum yttrium nitrogen film according to claim 6, characterized in that: The growth methods in step 1) and step 2) both adopt magnetron sputtering technology, and the growth method in step 3) adopts ultra-vacuum thermal evaporation technology.

8. The method for preparing a solar-blind ultraviolet optoelectronic artificial visual synapse device based on aluminum yttrium nitrogen film according to claim 6, characterized in that: Step 1) includes the following: Install the ITO target on the magnetron target position, and place the sapphire substrate after cleaning, drying and pretreatment on the substrate tray in the magnetron sputtering chamber, ensuring that the substrate is completely fitted to the bottom of the substrate without foreign matter; The pressure in the sputtering chamber was pumped down to 5×10 -4 Pa, and then fill the sputtering chamber with argon at a flow rate of 20 sccm, and then adjust the high valve to keep the internal gas pressure at 1 Pa. When the gas pressure is stable, adjust the sputtering power to 105 W, open the baffle after pre-sputtering for 5 minutes, and sputter for 1 minute, and finally obtain the ITO bottom electrode.

9. The method for preparing a solar-blind ultraviolet optoelectronic artificial visual synapse device based on aluminum yttrium nitrogen film according to claim 8, characterized in that: Step 2) includes the following: Install the aluminum target and the yttrium target on the target position of the magnetron, and place the sapphire substrate with the ITO bottom electrode obtained in step 1) on the substrate tray in the magnetron sputtering chamber to ensure that the substrate is completely in contact with the bottom of the substrate without any foreign matter; Cut the tin foil into appropriate size, attach it to part of the ITO bottom electrode surface, and stick the edge of the tin foil to the substrate tray with tape; The pressure in the sputtering chamber was pumped down to 5×10 -4 After 30 sccm, high-purity argon and high-purity nitrogen are filled into the sputtering chamber at a flow rate of 20 sccm, and high-purity oxygen is filled into the sputtering chamber at a flow rate of 15 sccm. Then the high valve is adjusted to keep the internal gas pressure at 1 Pa. When the gas pressure is stable, the two sputtering powers are adjusted to 100 W. After pre-sputtering for 5 minutes, the baffle is opened and the formal sputtering is performed for 15 minutes. Finally, an oxygen-rich aluminum yttrium nitrogen film is obtained. After the sputtering time for obtaining the oxygen-rich aluminum yttrium nitrogen film is reached, the film sputtering is stopped, and the introduction of nitrogen, argon and oxygen gases is suspended, and the process is continued for 20 minutes; after 20 minutes, high-purity argon and high-purity nitrogen are again filled into the sputtering chamber at a flow rate of 20 sccm, and the high valve is adjusted to keep the internal air pressure at 1 Pa. When the air pressure is stable, the two sputtering powers are adjusted to 100 W. After pre-sputtering for 5 minutes, the baffle is opened, and formal sputtering is performed for 15 minutes to obtain the oxygen-deficient aluminum yttrium nitrogen film; the oxygen-rich aluminum yttrium nitrogen film and the oxygen-deficient aluminum yttrium nitrogen film constitute a day-blind ultraviolet light responsive resistive switching layer.

10. The method for preparing a solar-blind ultraviolet optoelectronic artificial visual synapse device based on aluminum yttrium nitrogen film according to claim 9, characterized in that: Step 3) includes the following: Nickel metal particles are placed in a tungsten boat, and an ultra-high vacuum evaporation coating device is used to evaporate a metal nickel electrode on the surface of the aluminum yttrium nitrogen day-blind ultraviolet light responsive resistive layer using a circular hole mask with a diameter of 500 μm, where the thickness of the nickel electrode is 100 nm.

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