Self-powered visual adaptive optoelectronic memristor and preparation method thereof

Abstract

This invention discloses a self-powered, visually adaptive opto-memristor and its fabrication method, belonging to the field of microelectronic materials and devices technology. The opto-device includes: a metal electrode; a transparent electrode; and a photoelectric functional layer disposed between the metal bottom electrode and the transparent top electrode. The photoelectric functional layer is composed of zinc oxide (ZnO) and tungsten oxide (WO3). x Heterojunction thin film. The self-powered adaptive photoresistor of this invention, when stimulated by constant ultraviolet light without an applied external voltage, exhibits an adaptive phenomenon where the photocurrent first increases, then decreases, and finally remains stable over time. The self-powered visual adaptive device has a two-end structure, is simple in structure, easy to integrate, and its size can be reduced to the nanometer scale, providing a device foundation for realizing a brain-like neuromorphic visual system.

Description

Technical Field

[0001] This invention belongs to the field of microelectronic materials and artificial vision perception technology, and relates to a self-powered visual adaptive opto-memristor and its preparation method. Background Technology

[0002] Artificial visual perception systems have attracted widespread attention due to their integration of perception, memory, and processing functions, and are expected to play a key role in next-generation robotics and human sensory electronics. With the rapid development of artificial intelligence, there is a growing demand for artificial visual systems to mimic the visual perception capabilities of biological systems. One crucial function is visual adaptation, which automatically adjusts its response to stimuli based on different lighting environments. Visual adaptation enables organisms to process visual information effectively in constantly changing environments, thereby determining more appropriate behaviors. However, current research on visual adaptive devices mainly focuses on circuit construction using silicon-based transistors as logic devices, facing significant challenges such as large-scale integration, high power consumption, and low efficiency. Novel optoelectronic neuromorphic devices combine the advantages of photonics and electronics, showing great potential in the field of neuromorphic computing and attracting widespread attention from researchers both domestically and internationally. Furthermore, the current implementation of visual adaptive functions based on neuromorphic devices largely requires the application of external voltage, leading to additional energy consumption and cost. Therefore, achieving self-powered visual adaptive functions through material selection and structural design may provide a significant opportunity for the development of highly efficient and energy-saving neuromorphic visual systems for complex environments. Summary of the Invention

[0003] The purpose of this invention is to address the problems of large-scale integration, high power consumption, low efficiency, and additional power consumption of novel neuromorphic adaptive devices based on logic circuits in the prior art, by providing a self-powered visual adaptive opto-memristor and its fabrication method.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A visually adaptive memristor device based on an oxide heterojunction is characterized by comprising a transparent electrode, a metal electrode, and a photoresistive layer, wherein the photoresistive layer is disposed between the transparent electrode and the metal electrode; the photoresistive layer is a zinc oxide / tungsten oxide heterojunction thin film.

[0006] The transparent electrode is composed of multiple electrode pillars with a pore size of 100-300μm.

[0007] The thickness of the transparent electrode is 50±10nm; the thickness of the tungsten oxide in the photoresist layer is 180±10nm, and the thickness of the zinc oxide is 140±10nm.

[0008] A method for fabricating a visually adaptive memristor device based on an oxide heterojunction, characterized by comprising the following steps:

[0009] S1: Clean the SiO2 / Si substrate by sequentially ultrasonicating it with acetone, anhydrous ethanol, and deionized water for 15 minutes each, then drying it with nitrogen. Grow a tungsten metal bottom electrode on the SiO2 substrate using magnetron sputtering.

[0010] S2: A heterojunction photomembrane layer is obtained by sequentially growing tungsten oxide and zinc oxide thin films on the bottom electrode using magnetron sputtering.

[0011] S3: A transparent top electrode is prepared on the surface of the opto-memristor layer by sputtering deposition or thermal evaporation;

[0012] In step S2, the growth conditions for tungsten oxide are: 1 Pa pressure, argon and oxygen in a 2:1 ratio, and sputtering the tungsten oxide target at 60 W power for 30 minutes; the growth conditions for zinc oxide are: 1 Pa pressure, argon and oxygen in a 2:1 ratio, and sputtering the zinc oxide target at 80 W power for 30 minutes.

[0013] In step S3, the metal mask used for depositing the transparent electrode has an aperture of 100-300 μm and an electrode thickness of 50 ± 10 nm.

[0014] This invention provides a self-powered, visually adaptive opto-memristor and its fabrication method, belonging to the field of microelectronic materials and devices technology. The opto-device includes: a metal electrode; a transparent electrode; and a photoelectric functional layer disposed between the metal bottom electrode and the transparent top electrode. The photoelectric functional layer is composed of zinc oxide (ZnO) and tungsten oxide (WO3). x Heterojunction thin film. The self-powered adaptive photoresistor of this invention, when stimulated by constant ultraviolet light without an applied external voltage, exhibits an adaptive phenomenon where the photocurrent first increases, then decreases, and finally remains stable over time. The self-powered visual adaptive device has a two-end structure, is simple in structure, easy to integrate, and its size can be reduced to the nanometer scale, providing a device foundation for realizing a brain-like neuromorphic visual system.

[0015] The above-described technical solution of the present invention has the following beneficial technical effects:

[0016] The self-powered visual adaptive photoelectric memristor of this invention exhibits an adaptive phenomenon in which the photocurrent first increases, then decreases, and finally remains stable under constant ultraviolet light irradiation without external voltage. The visual adaptive device has a two-end structure, is simple in design, easy to integrate, and its size can be reduced to the nanometer scale. Furthermore, it can operate in a self-powered manner, providing a device foundation for realizing a brain-like neuromorphic visual system. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a self-powered, vision-adaptive opto-memristor; where 100 is the metal bottom electrode, 101 is the tungsten oxide layer, 102 is the zinc oxide layer, and 103 is the transparent top electrode.

[0018] Figure 2 This is a flowchart illustrating the fabrication process of a self-powered, vision-adaptive opto-memristor device constructed according to the present invention.

[0019] Figure 3 The current-voltage (IV) characteristic curve of the self-powered visual adaptive opto-memristor constructed in accordance with the present invention under dark conditions is shown.

[0020] Figure 4 The current-voltage (IV) characteristic curve of the self-powered visual adaptive opto-memristor constructed in accordance with the present invention under ultraviolet light irradiation is shown.

[0021] Figure 5 This describes the adaptive phenomenon of a self-powered, visually adaptive opto-memristor constructed according to the present invention under constant ultraviolet light irradiation.

[0022] Figure 6 This is a schematic diagram illustrating the working mechanism of the self-powered visual adaptive opto-memristor constructed according to the present invention. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0024] Example 1:

[0025] A self-powered visual adaptive opto-memristor device includes a transparent electrode, an opto-functional layer, and a metal electrode, wherein the opto-functional layer is disposed between the transparent electrode and the metal electrode.

[0026] The transparent electrode is an ITO thin film; the photoelectric functional layer is a zinc oxide / tungsten oxide heterojunction thin film; and the metal electrode is W.

[0027] The tungsten oxide film has a thickness of 180±10 nm; the zinc oxide film has a thickness of 140±10 nm; and the transparent electrode has a thickness of 50±10 nm.

[0028] Example 2:

[0029] A method for fabricating a self-powered, visually adaptive opto-memristor includes the following steps:

[0030] S1: Clean the SiO2 / Si substrate by sequentially ultrasonicating it with acetone, anhydrous ethanol, and deionized water in an ultrasonic cleaner for 15 minutes each, then drying it with nitrogen. A metal W-type substrate electrode is then grown on the SiO2 substrate using magnetron sputtering.

[0031] S2: Using magnetron sputtering, tungsten oxide thin films and zinc oxide thin films are sequentially grown on the bottom electrode to obtain a heterojunction optoelectronic functional layer;

[0032] More specifically, the magnetron sputtering conditions are as follows: the growth conditions for tungsten oxide are: 1 Pa pressure, argon and oxygen in a 2:1 ratio, sputtering the tungsten oxide target at 60 W power for 30 minutes; the growth conditions for zinc oxide are: 1 Pa pressure, argon and oxygen in a 2:1 ratio, sputtering the zinc oxide target at 80 W power for 30 minutes.

[0033] S3: A transparent top electrode is fabricated on the surface of the optoelectronic functional layer by magnetron sputtering, and a metal mask is used for masking during the fabrication process;

[0034] More specifically, the metal mask used for depositing transparent electrodes has an aperture of 100-300 μm and an electrode thickness of 50±10 nm.

[0035] Under the above conditions, a self-powered visual adaptive opto-memristor device with the effects described in this invention can be prepared.

[0036] Figure 1 This is a schematic diagram of the structure of a self-powered visual adaptive photoresistor constructed according to the present invention. The specific structure is as follows: a bottom electrode 100, which is a metal W; photoelectric functional layers 101 and 102 are prepared on the bottom electrode, which are tungsten oxide thin film and zinc oxide thin film, respectively; and a top electrode 103 is prepared on the photoelectric functional layer 102, which is a transparent electrode ITO.

[0037] Figure 2 This is a flowchart illustrating the fabrication method of a self-powered, visually adaptive opto-memristor constructed according to the present invention. The specific fabrication process is as follows:

[0038] Step 200: Clean the SiO2 / Si by ultrasonically cleaning it sequentially with acetone, anhydrous ethanol, and deionized water in an ultrasonic cleaner for 15 minutes each, then drying it with nitrogen. Grow a metal W-type substrate electrode on the SiO2 using magnetron sputtering.

[0039] Step 201: Grow a tungsten oxide film on the bottom electrode using magnetron sputtering. The tungsten oxide growth conditions are: 1 Pa pressure, argon and oxygen in a 2:1 ratio, and sputtering the tungsten oxide target with 60 W power for 30 minutes.

[0040] Step 202: A zinc oxide film is grown on a tungsten oxide film using magnetron sputtering. The growth conditions for zinc oxide are: 1 Pa pressure, argon and oxygen in a 2:1 ratio, and sputtering the zinc oxide target at 80 W power for 30 minutes.

[0041] Step 203: A transparent ITO top electrode is prepared by magnetron sputtering. During the deposition process, a metal mask with a 200 μm aperture is used for masking, and finally multiple independent top electrodes with a thickness of 50 ± 10 nm are formed.

[0042] Figure 3 This is a graph showing the current-voltage (IV) characteristics of a self-powered, vision-adaptive opto-memristor under dark conditions.

[0043] Figure 4 This is a current-voltage (IV) characteristic curve of a self-powered visual adaptive opto-memristor under ultraviolet light irradiation;

[0044] Electrical testing: Figure 3 and Figure 4 The comparison of the IV characteristics of the device under dark conditions and under ultraviolet light irradiation is shown. For example... Figure 3 As shown, for the initial device (i.e., without illumination), rectification can be observed by applying a continuous scan voltage from -2 V to 2 V, proving the existence of the zinc oxide / tungsten oxide heterojunction. Figure 4 As shown, the device under ultraviolet light irradiation produced a significant photocurrent, and there was still a photocurrent of 0.7 nA when the voltage was 0 V, which proves the self-powered capability of the photomemristor.

[0045] Figure 5 This describes the adaptive phenomenon of a self-powered, visually adaptive opto-memristor under constant ultraviolet light irradiation. Under zero bias, when a constant-intensity ultraviolet light pulse is applied to the device, the photocurrent response exhibits a behavior that first increases, then decreases, and finally stabilizes with the duration of illumination. This behavior is consistent with the visual adaptive behavior of humans suddenly entering a strong light environment. This indicates that the self-powered, visually adaptive opto-memristor proposed in this invention possesses the ability to simulate visual adaptive functions.

[0046] Figure 6 This is a schematic diagram illustrating the working mechanism of a self-powered, visually adaptive photoresistor. Zinc oxide and tungsten oxide form a type II heterojunction, which generates a photovoltaic-induced photocurrent under ultraviolet light stimulation. Photogenerated electrons are trapped by defects at the heterojunction interface, causing the photocurrent to gradually decrease over time, thus achieving visually adaptive behavior.

Claims

1. A self-powered, vision-adaptive opto-memristor, characterized in that: It includes a transparent top electrode, a metal bottom electrode, and a photoelectric functional layer, wherein the photoelectric functional layer is disposed between the transparent electrode and the metal electrode; The photoelectric functional layer consists of tungsten oxide and zinc oxide layers from bottom to top.

2. The self-powered visual adaptive photomemristor according to claim 1, characterized in that: The transparent electrode is composed of multiple electrode pillars.

3. A self-powered visual adaptive photomemristor according to claim 1 or 2, characterized in that: The transparent top electrode is indium tin oxide (ITO), and the metal bottom electrode is W or Ti.

4. The self-powered visual adaptive photomemristor according to claim 3, characterized in that: The tungsten oxide thickness of the optoelectronic functional layer is 180±10nm, and the zinc oxide thickness is 140±10nm.

5. A method for fabricating a self-powered visual adaptive opto-memristor, comprising the following steps: S1: Clean the SiO2 / Si substrate by sequentially ultrasonicating it with acetone, anhydrous ethanol, and deionized water for 15 minutes each, then drying it with nitrogen. Grow a tungsten metal bottom electrode on the SiO2 substrate using magnetron sputtering. S2: Using magnetron sputtering, tungsten oxide thin films and zinc oxide thin films are sequentially grown on the bottom electrode to obtain a heterojunction optoelectronic functional layer; S3: Prepare a transparent top electrode by sputtering deposition or thermal evaporation on the surface of the optoelectronic functional layer.

6. The method for fabricating a self-powered visual adaptive photomemristor according to claim 5, characterized in that: In step S2, the growth conditions for tungsten oxide are: 1 Pa pressure, argon and oxygen in a 2:1 ratio, and sputtering the tungsten oxide target at 60 W power for 30 minutes; the growth conditions for zinc oxide are: 1 Pa pressure, argon and oxygen in a 2:1 ratio, and sputtering the zinc oxide target at 80 W power for 30 minutes.

7. A method for fabricating a self-powered visual adaptive photomemristor according to claim 5 or 6, characterized in that: In step S3, the metal mask used for depositing the transparent electrode has an aperture of 100-300 μm and an electrode thickness of 50 ± 10 nm.

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