Preparation method of flexible photoelectric synaptic device with data erasing function

Abstract

The invention relates to a preparation method of a flexible photoelectric synapse device, in particular to a preparation method of a flexible photoelectric synapse device with a data erasing function. The flexible photoelectric synapse device is simple in structure and low in cost and has a data erasing function. Defects are generated in the material by bending the device to induce neutralization of ionization oxygen vacancies, so that the conductivity of the thin film is reduced to realize data erasing, and a method for quickly erasing data is provided for the metal oxide semiconductor-based photoelectric synapse device; and a new solution is provided for data erasing of the metal-oxide semiconductor-based photoelectric synapse device with a metal-semiconductor-metal structure. The flexible photoelectric synapse device provided by the invention can simulate the function and behavior of a biological synapse in a highly similar manner, has a storage bit width greater than 5 bits, and shows excellent performance.

Description

Technical Field

[0001] The present invention relates to a method for preparing a flexible optoelectronic synaptic device, and more specifically to a method for preparing a flexible optoelectronic synaptic device with a data erasing function. Background Art

[0002] The digital logic computing system based on von Neumann can efficiently process complex structured data, but its memory and processor are physically separated, which has become a bottleneck that hinders its efficient processing of unstructured data. The human brain is particularly effective in processing unstructured data, so using traditional micro-nanoelectronic devices to simulate human brain functions has become the focus of scientific research.

[0003] Among them, photoelectric synaptic devices are a new type of electronic device that combines the photoelectric effect and synaptic behavior. They can simulate the function of biological synapses (connection points between neurons) and realize the storage, processing and transmission of information through the mutual conversion and transmission of optical signals and electrical signals. Most of the photoelectric synaptic devices prepared by the prior art are three-terminal transistor structures, which change the concentration of carriers in the material through light stimulation or gate voltage, thereby realizing the function of data storage and erasure.

[0004] However, this complex structure leads to high preparation costs and is not suitable for large-scale growth and manufacturing. The two-terminal planar optoelectronic synapse device has a simple structure, which greatly reduces the manufacturing cost. Although the planar optoelectronic synapse device can also simulate the functions and behaviors of many biological synapses, the data stored in it is difficult to erase. Therefore, it is of great significance to develop an optoelectronic synapse device with a simple structure and an erasing function. Summary of the invention

[0005] The present invention provides a method for preparing a flexible optoelectronic synapse device with a data erasing function, aiming to obtain a flexible optoelectronic synapse device with a simple structure, low manufacturing cost and a data erasing function.

[0006] The above purpose is achieved through the following technical solutions:

[0007] A flexible optoelectronic synaptic device with data erasing function includes a flexible polymer substrate, such as a PET substrate or a PI substrate, an amorphous gallium oxide film formed on the flexible substrate, and two symmetrical metal (such as Au, Ag, Cu, etc.) electrodes formed on the amorphous gallium oxide film.

[0008] A flexible optoelectronic synaptic device with data erasing function is applied to light-assisted strain sensors.

[0009] A method for preparing a flexible optoelectronic synaptic device with a data erasing function comprises the following steps:

[0010] Step 1: Pump the growth chamber pressure to 4×10 -5 Pa, oxygen is introduced to make the growth chamber pressure 1-3Pa;

[0011] Step 2: Using a pulsed laser to burn the gallium oxide target material, thereby growing an amorphous gallium oxide film on a flexible substrate;

[0012] Step 3: Deposit a metal electrode on the amorphous gallium oxide film to form a metal electrode with symmetric material and area.

[0013] The flexible substrate was ultrasonically cleaned in deionized water, anhydrous ethanol, acetone and isopropanol in sequence before use.

[0014] Each ultrasonic cleaning lasts 5-15 minutes.

[0015] The pulse laser wavelength is 355nm, the energy is 20-200mJ / pulse, the pulse width is 3-5ns, and the frequency is 5-20Hz.

[0016] The target burning time is 30-90min.

[0017] The metal electrode is deposited on the amorphous gallium oxide film by ion beam sputtering, thermal evaporation or electron beam evaporation.

[0018] Flexible polymer substrate The single side size of the substrate is 5-15mm, and the electrode size is 1×0.7mm 2 .

[0019] A photoelectric synaptic device is prepared by the above preparation method, forming an amorphous gallium oxide film on a flexible polymer substrate, and finally forming two symmetrical metal electrodes on the amorphous gallium oxide film.

[0020] The beneficial effects of the method for preparing a flexible optoelectronic synaptic device with data erasing function of the present invention are:

[0021] By bending the device, defects are generated inside the material, inducing the neutralization of ionized oxygen vacancies, thereby reducing the conductivity of the film to achieve data erasure. This provides a method for quickly erasing data in metal oxide semiconductor-based optoelectronic synaptic devices; and provides a new solution for erasing data in metal oxide semiconductor-based optoelectronic synaptic devices with a metal-semiconductor-metal structure.

[0022] The provided flexible optoelectronic synaptic device can simulate the functions and behaviors of biological synapses with a high degree of similarity, and has a storage bit width greater than 5 bits, showing excellent performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of the flexible optoelectronic synapse device prepared by the present invention;

[0024] Figure 2 This is a current-time curve diagram of the flexible optoelectronic synaptic device prepared by the present invention under two consecutive 254nm light pulse stimulations;

[0025] Figure 3 The curve of the change of the PPF index of the flexible optoelectronic synaptic device prepared by the present invention with the pulse time interval and the double exponential fitting curve diagram;

[0026] Figure 4 Current-time curves of the flexible optoelectronic synaptic device prepared in the present invention under stimulation of 254 nm light pulses with (a) different pulse widths, (b) different pulse intensities, (c) and (d) different pulse numbers.

[0027] Figure 5 The dark current-voltage curve of the flexible optoelectronic synaptic device prepared by the present invention at different bending degrees;

[0028] Figure 6 The current-voltage curve of the flexible optoelectronic synaptic device prepared by the present invention under different bending degrees at 254nm illumination;

[0029] Figure 7 This is a storage-erase cycle test diagram of the flexible optoelectronic synaptic device prepared by the present invention;

[0030] Figure 8 The photoresponse performance of optoelectronic synaptic devices under different reaction pressures. DETAILED DESCRIPTION

[0031] A method for preparing a flexible optoelectronic synaptic device with a data erasing function, in Embodiment 1, comprises the following steps:

[0032] Step 1: Make the size of 10×10mm 2 Flexible polymer substrates (such as PET) of different sizes are ultrasonically cleaned in deionized water, anhydrous ethanol, acetone and isopropanol in turn, each ultrasonic cleaning lasts for 10 minutes, and then blown dry with a dry nitrogen flow to obtain a clean PET substrate.

[0033] Step 2: The clean PET substrate is transferred to the growth chamber, and the gallium oxide is used as the target. The growth chamber pressure is pumped to 4×10 -5 During growth, turn on the oxygen cylinder switch, adjust the flow rate to 20 sccm, and adjust the gate valve until the pressure in the growth chamber is 1-3 Pa, and blue glow will be generated in the growth chamber.

[0034] The growth chamber may adopt a low-pressure molecular beam epitaxy growth device (model LMBE 450) produced by Shen Ke Instruments.

[0035] Step 3: At room temperature, use a pulsed laser to burn the target for 60 minutes using a pulsed laser with a wavelength of 355 nm, an energy of 120 mJ / pulse, a pulse width of 5 ns, and a frequency of 10 Hz, thereby completing the growth of the amorphous gallium oxide film.

[0036] Step 4: Use ion beam sputtering technology to deposit gold (Au) electrodes on the amorphous gallium oxide film: Use a mask to prepare an Au / Au symmetric electrode with a thickness of 60nm, a length of 1mm, a width of 0.7mm, and a channel width of 0.1mm on the amorphous gallium oxide film to obtain a flexible optoelectronic synaptic device with data erasing function.

[0037] During the growth process of metal oxide semiconductor materials, abundant oxygen vacancies will inevitably be generated, leading to the phenomenon of persistent photoconductivity (PPC) in the device, which gives the device the ability to store optical information. The photoexcitation-induced ionization of oxygen vacancies is the intrinsic mechanism of the PPC effect of metal oxide semiconductor devices. The ionization of oxygen vacancies will release excess carriers to increase the conductivity of the film. The neutralization of oxygen vacancies requires overcoming an energy barrier, so under natural conditions, the neutralization of oxygen vacancies is a relaxation process. Under the action of bending stress, slip planes will be generated in the material, and many defects will be generated on the slip planes. These defects can serve as recombination centers for ionized oxygen vacancies and electrons, promote the neutralization of ionized oxygen vacancies, and reduce the conductivity of the film. This is the basis for realizing the function of erasing data by bending the device. Reference Figure 7 , which is a storage-erase cycle test of embodiment 1.

[0038] When the reactor pressure is adjusted to 4 Pa ​​or above during the growth of amorphous gallium oxide, Example 2 is obtained. Figure 8 As shown, the test found that the device of Example 2 has a large resistance and a fast light response characteristic, but does not have a photoelectric synapse characteristic.

[0039] like Figure 5 As shown, the photocurrent of the flexible optoelectronic synaptic device provided at different bending degrees has obvious differences. The reason is that the material strain promotes the neutralization of ionized oxygen vacancies, and the neutralization efficiency is positively correlated with the strain degree. It can also be used as a highly sensitive light-assisted strain sensor.

Claims

1. A flexible optoelectronic synaptic device with data erasing function, characterized in that: The invention comprises a flexible polymer substrate, an amorphous gallium oxide film formed on the flexible substrate, and two symmetrical metal electrodes formed on the amorphous gallium oxide film.

2. A flexible optoelectronic synaptic device with data erasing function, characterized in that: Application in light-assisted strain sensors.

3. A method for preparing a flexible optoelectronic synaptic device with data erasing function, characterized in that: The following steps are involved: Step 1: Pump the growth chamber pressure to 4×10 -5 Pa, oxygen is introduced to control the pressure in the growth chamber at 1-3Pa; Step 2: Using a pulsed laser to burn the gallium oxide target material, thereby growing an amorphous gallium oxide film on a flexible substrate; Step 3: Deposit a metal electrode on the amorphous gallium oxide film to form a metal electrode with symmetrical electrode material and electrode area.

4. The preparation method according to claim 3, characterized in that: The flexible substrate was ultrasonically cleaned in deionized water, anhydrous ethanol, acetone and isopropanol in sequence before use.

5. The preparation method according to claim 4, characterized in that: Each ultrasonic cleaning lasts 5-15 minutes.

6. The preparation method according to claim 3, characterized in that: The pulse laser wavelength is 355nm, the energy is 20-200mJ / pulse, the pulse width is 3-5ns, and the frequency is 5-20Hz.

7. The preparation method according to claim 3 or 6, characterized in that: The target burning time is 30-90min.

8. The preparation method according to claim 3, characterized in that: The metal electrode is deposited on the amorphous gallium oxide film by ion beam sputtering, thermal evaporation or electron beam evaporation.

9. The preparation method according to claim 3, characterized in that: Flexible polymer substrate The single side size of the substrate is 5-15mm, and the electrode size is 1×0.7mm 2 .

10. A photoelectric synaptic device, characterized in that: The method of claim 3 is used to form an amorphous gallium oxide film on a flexible polymer substrate, and finally two symmetrical metal electrodes are formed on the amorphous gallium oxide film.

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