Zinc oxide / molybdenum disulfide-based multifunctional photoelectric memristor and preparation method thereof

Abstract

The invention discloses a multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide and a preparation method, the memristor integrates multiple functions of nonvolatile storage, artificial brain-like synapse and wireless communication, and comprises a bottom electrode layer, a resistive function layer and a top electrode layer which are sequentially designed from bottom to top and located on a substrate, the resistive function layer is a heterojunction formed by a zinc oxide film and a molybdenum disulfide film. According to the memristor, the characteristic that molybdenum disulfide inhibits overgrowth of the conductive filaments is utilized, the operation power consumption is reduced, the resistance storage window and the stability are improved, and therefore the performance of the memristor can be remarkably optimized.

Description

Technical Field

[0001] The invention belongs to the technical field of microelectronic devices, and in particular relates to a multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide and a preparation method thereof. Background Art

[0002] As a typical representative of traditional computer architecture, the von Neumann architecture has problems such as memory bottleneck, instruction pipeline limitation, memory access delay, security and concurrency, and scalability due to the "storage-computing" separation architecture. These problems are particularly prominent when processing big data and complex computing tasks, limiting the performance and efficiency of computer systems. In order to break through the bottleneck of the current traditional computer system architecture, it is urgent to develop new computing methods and architectures. The new computer architecture constructed by artificial synapses provides a reliable solution. It introduces neuromorphic computing similar to the computing architecture of the human brain. By integrating storage and computing in the same unit, it fundamentally overcomes the limitations of the von Neumann architecture. In addition, with the advent of the 5G / 6G era, traditional devices for controlling signal channel conversion face problems such as high power consumption, which greatly hinders the improvement of communication efficiency. Memristor, a two-terminal nonlinear element with memory function for the charge flowing through it, has the advantages of low power consumption, low latency, non-volatility, and high integration. It has received great attention in the field of neuromorphic computing and wireless communication.

[0003] In recent years, memristors have shown great potential in the fields of artificial intelligence, high-performance computing, big data storage systems, wearable devices, energy management systems, smart sensor networks, and wireless communications due to their unique properties. In particular, in the field of wireless communications, the application of memristors opens up the possibility of improving signal processing efficiency and data transmission speed, contributing to the development of 5G / 6G and future communication technologies. They are not only suitable for the construction of efficient and energy-optimized neurobionic systems, but also show great potential in the field of data storage due to their non-volatile memory characteristics, improving data storage density and access speed. In addition, the advantages of memristors in the development of low-energy computing devices and smart sensors are particularly critical for promoting the development of the Internet of Things and smart cities. These applications not only promote the advancement of science and technology and industry, but also provide innovative solutions to meet the information processing and storage challenges of modern society.

[0004] At present, the most mature memristors are based on oxide material systems, among which oxide memristors, which mainly use transition metal oxides as the resistive switching functional layer, are regarded as very promising memristive brain-like devices because of their excellent performances such as high speed, low power consumption, easy integration, high storage density, unique resistance change characteristics, and compatibility with CMOS processes. Although oxide memristors have great potential, there are still some problems that limit their development in practical applications, such as device stability, durability, and consistent performance of array units, which need further optimization and improvement. Recently, molybdenum disulfide, as an emerging transition metal chalcogenide, has been widely used in the manufacture of high-performance nanoelectronic devices, and memristive switching behavior has been observed. Applying molybdenum disulfide to oxide memristors can significantly optimize the performance of memristors, such as increasing the resistance storage window, reducing operating power consumption, and improving stability. Summary of the invention

[0005] Purpose of the invention: The present invention aims to provide a multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide to improve the performance of oxide memristors and realize multifunctional applications such as integrated non-volatile storage, brain-like synapses, and wireless communications.

[0006] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is: A multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide, the memristor integrating multiple functions including non-volatile storage, artificial brain-like synapses, and wireless communication, including a bottom electrode layer, a resistive switching functional layer, and a top electrode layer designed sequentially from bottom to top and located on a substrate, wherein the resistive switching functional layer is a heterojunction formed by a zinc oxide thin film and a molybdenum disulfide thin film.

[0007] Preferably, the memristor exhibits typical non-volatility under the stimulation of an excitation signal, and is used for non-volatile storage and artificial convolutional neural networks to improve the accuracy of calculation and recognition results.

[0008] Preferably: when the excitation signal changes, by repeatedly scanning the memristor multiple times, the response current gradually increases or decreases, which is similar to the enhancement and inhibition behavior of synapses, and can be used to simulate brain-like neural synapses and realize neuromorphic computing.

[0009] Preferably, the excitation signal of the memristor includes an electrical signal, an optical signal or a photoelectric cooperative signal.

[0010] Preferably: by introducing a molybdenum disulfide film and a zinc oxide film to form a heterojunction, the formation of conductive filaments is regulated by utilizing their unique structural characteristics, thereby improving the stability of the device.

[0011] Compared with zinc oxide memristors without molybdenum disulfide, the response speed of zinc oxide / molybdenum disulfide heterojunction memristors after the introduction of molybdenum disulfide has been significantly improved. The response time is in the nanosecond order and can be used in the field of high-frequency electronic information, such as as a signal control device for 5G / 6G wireless communications to control the conversion of signal channels.

[0012] Preferably: the memristor is used as a signal control device. When the excitation signal is changed so that the memristor is in a low-resistance state, the memristor signal control device is in an "ON" state; when the excitation signal is changed so that the memristor is in a high-resistance state, the memristor signal control device is in an "OFF" state. By utilizing the non-volatility of the memristor, when the excitation signal is withdrawn, the memristor signal control device maintains the original "ON" or "OFF" state. Compared with traditional signal control devices that require a bias voltage to be applied during the entire working process, the memristor signal control device can reduce power consumption and save costs.

[0013] Another object of the present invention is to provide a method for preparing a multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide, comprising the following steps: Step S1: preparing a bottom electrode: depositing a bottom electrode on a silicon substrate by using a DC magnetron sputtering method.

[0014] Step S2: preparing a molybdenum disulfide film: depositing molybdenum disulfide on the silicon wafer obtained in step S1 by using a radio frequency magnetron sputtering method.

[0015] Step S3: preparing a zinc oxide layer: depositing zinc oxide on the silicon wafer obtained in step S2 by using a radio frequency magnetron sputtering method.

[0016] Step S4: preparing the top electrode: attaching the mask plate to the silicon wafer obtained in step S3, and depositing the top electrode on the zinc oxide layer by DC magnetron sputtering to obtain an artificial synaptic device based on zinc oxide / molybdenum disulfide memristor.

[0017] Preferably: in the step S1, the bottom electrode is made of one of platinum, gold or tungsten; in the step S4, the top electrode is made of one of silver, iron or copper.

[0018] Preferably, the thickness of the top electrode and the bottom electrode are both 80-100 nanometers; in the step S2, the thickness of the molybdenum disulfide film is 5-20 nanometers; in the step S3, the thickness of the zinc oxide film is 40-60 nanometers.

[0019] Preferably: in the step S4, the top electrode pattern is rectangular or circular, and the size of the top electrode pattern is 100-500 microns.

[0020] Compared with the prior art, the present invention has the following beneficial effects: (1) The integrated multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide and its preparation method proposed in the present invention uses a novel zinc oxide / molybdenum disulfide heterostructure as a functional layer to form an artificial synaptic device with a sandwich structure with a top electrode and a bottom electrode. The preparation method has simple operation steps, low energy consumption and high yield. The memristor using Cu and W as electrode materials can enhance the compatibility of the device's back-end process and is suitable for large-scale production.

[0021] (2) The integrated multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide proposed in the present invention can simultaneously realize multiple functions such as non-volatile storage, artificial brain-like synapses, and wireless communication. It can be used in the fields of big data storage, high-performance neuromorphic computing, high-frequency photonic / electronic devices, etc., and promote the research and development of highly integrated and miniaturized brain-like chips.

[0022] (3) The present invention introduces a new heterojunction composed of molybdenum disulfide material and zinc oxide as the resistive switching functional layer of the memristor. The blocking effect of molybdenum disulfide on metal ions is utilized to inhibit the excessive growth of metal conductive filaments, thereby significantly improving the stability of the memristor.

[0023] The integrated multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide proposed in the present invention has a resistance as low as 18 ohms in a low resistance state, which can significantly reduce power consumption and insertion loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a schematic diagram of the structure and electrical test of a zinc oxide / molybdenum disulfide memristor, in which Ag is silver, ZnO is zinc oxide, MoS2 is molybdenum disulfide, Pt is platinum, and Si is silicon.

[0025] Figure 2 Current-voltage curve based on ZnO / MoS2 memristor.

[0026] Figure 3 Resistance distribution of ZnO / MoS2-based memristor under multiple switching cycles.

[0027] Figure 4 The present invention provides a method for simulating excitatory postsynaptic currents based on a zinc oxide / molybdenum disulfide memristor under light stimulation of different durations.

[0028] Figure 5 The invention discloses a method for simulating double-pulse alienation characteristics of a zinc oxide / molybdenum disulfide memristor under two consecutive light pulses.

[0029] Figure 6 This is a signal transmission curve of a zinc oxide / molybdenum disulfide memristor in an on state according to the present invention.

[0030] Figure 7This is a signal transmission curve of a zinc oxide / molybdenum disulfide memristor in an off state according to the present invention. DETAILED DESCRIPTION

[0031] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0032] This embodiment provides a multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide, such as Figure 1 As shown, the memristor integrates multiple functions such as non-volatile storage, artificial brain-like synapses, and wireless communication, including a bottom electrode layer, a resistive switching functional layer, and a top electrode layer designed from bottom to top and located on a substrate, wherein the electrode layer and the functional layer are prepared by magnetron sputtering or electron beam evaporation, and the resistive switching functional layer is a heterojunction composed of a zinc oxide thin film and a molybdenum disulfide thin film.

[0033] In another embodiment, the memristor exhibits typical non-volatility under the stimulation of an excitation signal, and is used in non-volatile storage and artificial convolutional neural networks to improve the accuracy of calculation and recognition results.

[0034] In another embodiment, when the excitation signal changes, by repeatedly scanning the memristor, the response current gradually increases or decreases, which is similar to the enhancement and inhibition behavior of synapses. Positive electrical signals and optical signals can achieve synaptic enhancement, and negative electrical signals can achieve synaptic inhibition. It can be used to simulate brain-like neural synapses and realize neuromorphic computing.

[0035] In another embodiment, the excitation signal of the memristor includes an electrical signal, an optical signal, or an optoelectronic cooperative signal.

[0036] The device in this embodiment is based on the electrochemical metallization (ECM) mechanism, and the resistance switching is achieved by the on and off of the silver conductive filaments. Since the mobility of silver ions in molybdenum disulfide is low, the introduction of molybdenum disulfide as a barrier layer between the zinc oxide dielectric layer and the bottom electrode can effectively inhibit the silver ions from entering the bottom electrode, thereby inhibiting the excessive growth of the conductive filaments, inhibiting the negative turn-on phenomenon of the device, and improving the stability of the device. At the same time, the introduction of the molybdenum disulfide film and the zinc oxide film to form a type II heterojunction increases the interface barrier, which helps to achieve the photoelectric synapse regulation of the device.

[0037] In another embodiment, compared with a zinc oxide memristor without molybdenum disulfide, the response speed of the zinc oxide / molybdenum disulfide heterojunction memristor after introducing molybdenum disulfide is significantly improved, and the response time is in the nanosecond order, and can be used in the field of high-frequency electronic information, such as as a signal control device for 5G / 6G wireless communications to control the conversion of signal channels.

[0038] The memristor is used as a signal control device. When the excitation signal is changed to make the memristor in a low-resistance state, the memristor signal control device is in an "ON" state; when the excitation signal is changed to make the memristor in a high-resistance state, the memristor signal control device is in an "OFF" state. By utilizing the non-volatility of the memristor, when the excitation signal is withdrawn, the memristor signal control device maintains the original "ON" or "OFF" state. Compared with traditional signal control devices that require a bias voltage to be applied during the entire working process, the memristor signal control device can reduce power consumption and save costs.

[0039] The present invention utilizes the property of molybdenum disulfide to inhibit excessive growth of conductive filaments, so that the device has excellent electrical properties, lower operating voltage, lower energy consumption and stronger stability. The memristor integrates multiple functions of non-volatile storage, artificial brain-like synapses, and wireless communication, and is applied to the fields of big data storage, high-performance neuromorphic computing, high-frequency photon / electronic devices, etc., providing a technical feasibility for the research and development of highly integrated, miniaturized, and multifunctional brain-like chips, and the preparation method has simple operation steps, low energy consumption, high yield, and is suitable for large-scale production.

[0040] In another embodiment, a method for preparing a multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide is provided, comprising the following steps: Step S1: Prepare the bottom electrode: Deposit the bottom electrode on the silicon substrate (Si substrate) by DC magnetron sputtering, and the bottom electrode thickness is 80-100 nanometers. In this embodiment, the bottom electrode is made of platinum. In another embodiment, the bottom electrode is made of gold. In another embodiment, the bottom electrode is made of tungsten.

[0041] Step S2: preparing a molybdenum disulfide film: depositing molybdenum disulfide (MoS2) on the silicon wafer obtained in step S1 by radio frequency magnetron sputtering to obtain a molybdenum disulfide film having a thickness of 5 to 20 nanometers.

[0042] Step S3: preparing a zinc oxide layer: depositing zinc oxide (ZnO) on the silicon wafer obtained in step S2 by radio frequency magnetron sputtering to obtain a zinc oxide film with a thickness of 40 to 60 nanometers.

[0043] Step S4: preparing the top electrode: attaching the mask plate to the silicon wafer obtained in step S3, and depositing the top electrode on the zinc oxide layer by DC magnetron sputtering to obtain an artificial synaptic device based on zinc oxide / molybdenum disulfide memristor. In this embodiment, the top electrode is made of silver (Ag). In another embodiment, the top electrode is made of iron. In another embodiment, the top electrode is made of copper. The thickness of the top electrode is 80 to 100 nanometers. The top electrode pattern is rectangular or circular, and the size of the top electrode pattern is 100 to 500 micrometers.

[0044] In another embodiment, a specific example of a method for preparing a multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide is provided, comprising the following steps: Step S1: preparing a bottom electrode: depositing bottom electrode platinum on a silicon substrate by DC magnetron sputtering, and controlling the electrode thickness to be 100 nanometers; Step S2: preparing molybdenum disulfide: depositing molybdenum disulfide on the silicon wafer obtained in step S1 by using radio frequency magnetron sputtering; Step S3: preparing zinc oxide: depositing zinc oxide on the silicon wafer obtained in step S2 by radio frequency magnetron sputtering; Step S4: preparing the top electrode: attaching the mask plate to the silicon wafer obtained in step S4, and depositing the top electrode silver on the zinc oxide layer by DC magnetron sputtering to obtain an artificial synaptic device based on zinc oxide / molybdenum disulfide memristor.

[0045] Specifically, the method firstly deposits a 100-nanometer-thick platinum film on a 500-micron-thick silicon wafer using a DC magnetron sputtering method, and the entire platinum film serves as a bottom electrode; Next, a 5-nanometer-thick molybdenum disulfide film was deposited on the platinum film using radio frequency magnetron sputtering; Then, a 60-nanometer-thick zinc oxide film was deposited on the molybdenum disulfide film by radio frequency magnetron sputtering; Finally, a silver electrode is plated on the zinc oxide layer. First, a mask is attached to the zinc oxide, which is placed in a magnetron sputtering chamber and plated with a 100-nanometer silver film to obtain a multifunctional device based on zinc oxide / molybdenum disulfide memristor. The top electrode pattern is a rectangle of 450 microns × 450 microns. The structure of the device is silver top electrode / zinc oxide film / molybdenum disulfide film / platinum bottom electrode (such as Figure 1 as shown).

[0046] The electrical performance of the device is tested below. During the test, the bottom electrode is grounded and the top electrode is connected to a positive voltage. Figure 1 shown.

[0047] Figure 2 yes Figure 1Figure 1 shows the current-voltage characteristic curve of the device in Figure 2. By sweeping the bias voltage (0 V → 1.5 V → -1.6 V → 0 V), the current shows a significant jump, indicating that the device is switching from a high-resistance state to a low-resistance state. When the voltage is swept back, the current suddenly drops to nearly zero, indicating that the device is returning from a low-resistance state to a high-resistance state.

[0048] Figure 3 yes Figure 1 The resistance distribution of the device after multiple switching cycles. The figure shows that the resistance distribution of the device has good uniformity, and it can still maintain stable switching after nearly 600 cycles, and the low-resistance state resistance is as low as 18 ohms.

[0049] Figure 4 yes Figure 1 The device simulates the characteristics of excitatory postsynaptic current under light stimulation of different durations. When light stimulation of different durations is applied to the device, the response current of the device increases with the increase of light exposure time. When the light is removed, the current of the device slowly drops back, which well simulates the characteristics of excitatory postsynaptic current in biological synapses.

[0050] Figure 5 yes Figure 1 The device simulates the double pulse factorization (PPF) characteristic. When two consecutive light pulses are applied to the device, the response current of the second pulse is larger than that of the first pulse, which simulates the PPF characteristic well.

[0051] Figure 6 and Figure 7 yes Figure 1 The transfer characteristic curves of the device in the on and off states. First, a DC pulse is applied to the device to keep it in the on or off state. Then, an AC sinusoidal signal with a frequency of 1 MHz and a peak-to-peak value of 100 mV is applied to one end of the device, and the other end is connected to an oscilloscope. It can be observed that when the device is in the on state, the signal at the input end can be completely output by the device at the output end ( Figure 6 ), while in the off state, the input signal is blocked by the device and there is no output signal at the output ( Figure 7 ), which proves that the device has good transmission capability for input signals and can be applied in the field of high-speed wireless communications.

[0052] In the present invention, the device preparation method has simple operation steps, low energy consumption, high yield rate, and is suitable for large-scale production. The present invention utilizes the excellent characteristics of molybdenum disulfide / zinc oxide materials to design and prepare a new type of memristor, aiming to overcome the problems in the prior art and realize a multifunctional integrated device with low power consumption, high stability and scalability to meet the needs of processing large-scale data and complex tasks.

[0053] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide, characterized in that: It comprises a bottom electrode layer, a resistive switching functional layer and a top electrode layer which are designed in sequence from bottom to top and are located on a substrate. The resistive switching functional layer is a heterojunction formed by a zinc oxide film and a molybdenum disulfide film.

2. The multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide according to claim 1, characterized in that: The memristor exhibits typical non-volatility under the stimulation of an excitation signal and is used for non-volatile storage and artificial convolutional neural networks.

3. The multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide according to claim 2, characterized in that: When the excitation signal changes, by repeatedly scanning the memristor, the response current gradually increases or decreases, which is similar to the enhancement and inhibition behavior of synapses. It can be used to simulate brain-like neural synapses and realize neuromorphic computing.

4. The multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide according to claim 3, characterized in that: The excitation signal of the memristor includes an electrical signal, an optical signal or a photoelectric cooperative signal.

5. The multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide according to claim 4, characterized in that: By introducing molybdenum disulfide film and zinc oxide film to form a heterojunction and utilizing their unique structural properties, the formation of conductive filaments can be regulated to improve the stability of the device.

6. The multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide according to claim 5, characterized in that: The memristor is used as a signal control device. When the excitation signal is changed to make the memristor in a low-resistance state, the memristor signal control device is in an "on" state; when the excitation signal is changed to make the memristor in a high-resistance state, the memristor signal control device is in an "off" state. By utilizing the non-volatility of the memristor, when the excitation signal is withdrawn, the memristor signal control device maintains the original "on" or "off" state.

7. A method for preparing a multifunctional photoelectric memristor based on zinc oxide / molybdenum disulfide according to claim 1, characterized in that: The steps include: Step S1: preparing a bottom electrode: depositing a bottom electrode on a silicon substrate by using a DC magnetron sputtering method; Step S2: preparing a molybdenum disulfide film: depositing molybdenum disulfide on the silicon wafer obtained in step S1 by using a radio frequency magnetron sputtering method; Step S3: preparing a zinc oxide layer: depositing zinc oxide on the silicon wafer obtained in step S2 by using a radio frequency magnetron sputtering method; Step S4: preparing the top electrode: attaching the mask plate to the silicon wafer obtained in step S3, and depositing the top electrode on the zinc oxide layer by DC magnetron sputtering to obtain an artificial synaptic device based on zinc oxide / molybdenum disulfide memristor.

8. The preparation method according to claim 7, characterized in that: In the step S1, the bottom electrode is made of one of platinum, gold or tungsten; in the step S4, the top electrode is made of one of silver, iron or copper.

9. The preparation method according to claim 7, characterized in that: The thickness of the top electrode and the bottom electrode are both 80-100 nanometers; in the step S2, the thickness of the molybdenum disulfide film is 5-20 nanometers; in the step S3, the thickness of the zinc oxide film is 40-60 nanometers.

10. The preparation method according to claim 7, characterized in that: In the step S4, the top electrode pattern is rectangular or circular, and the size of the top electrode pattern is 100-500 microns.

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