A method for preparing a flexible optoelectronic synapse device with data erasing function

Abstract

The present application relates to a preparation method of a flexible optoelectronic synapse device, and more particularly to a preparation method of a flexible optoelectronic synapse device with data erasing function. To obtain a flexible optoelectronic synapse device with simple structure, low cost and data erasing function. By bending the device, defects are generated inside the material, which induces the neutralization of ionized oxygen vacancies, thereby reducing the conductivity of the thin film to achieve data erasing, providing a method for quickly erasing data for metal-oxide-semiconductor-based optoelectronic synapse devices. A new solution is provided for erasing data for metal-oxide-semiconductor-based optoelectronic synapse devices with metal-semiconductor-metal structure. The flexible optoelectronic synapse device provided can highly simulate the function and behavior of biological synapses, and has a storage bit width of more than 5 bits, showing excellent performance.

Description

TECHNICAL FIELD

[0001] The present application relates to a preparation method of a flexible optoelectronic synapse device, and more particularly to a preparation method of a flexible optoelectronic synapse device with data erasing function. BACKGROUND

[0002] The Von Neumann-based digital logic computing system can efficiently process complex structured data, but its memory and processor are physically separated, which becomes a bottleneck for efficient processing of unstructured data. Human brain is particularly effective in processing unstructured data, so simulating the function of human brain with traditional micro-nano electronic devices has become the focus of scientific research.

[0003] Among them, the optoelectronic synapse device is a new type of electronic device combining 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. The optoelectronic synapse devices prepared by the prior art are mostly three-terminal transistor structures, which change the concentration of carriers in the material by light stimulation or gate voltage, thereby realizing the functions of data storage and erasing.

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

[0005] The present application provides a preparation method of a flexible optoelectronic synapse device with data erasing function, which aims to obtain a flexible optoelectronic synapse device with simple structure, low manufacturing cost and data erasing function.

[0006] The above-mentioned purpose is achieved by the following technical solutions:

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

[0008] A flexible optoelectronic synapse device with data erasing function is applied to an optical-assisted strain sensor.

[0009] A preparation method of a flexible optoelectronic synapse device with data erasing function, comprising the following steps:

[0010] Step one, the pressure of the growth chamber is extracted to 4*10 -5 Pa, oxygen is introduced to make the pressure of the growth chamber 1-3 Pa;

[0011] Step two, amorphous gallium oxide film is grown on the flexible substrate by burning the gallium oxide target with pulsed laser;

[0012] Step three, metal electrode deposition is performed on the amorphous gallium oxide film to form material and area symmetrical metal electrodes.

[0013] The flexible substrate is sequentially placed in deionized water, anhydrous ethanol, acetone and isopropanol for ultrasonic cleaning before use.

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

[0015] The pulsed laser has a wavelength of 355 nm, an energy of 20-200 mJ / pulse, a pulse width of 3-5 ns and a frequency of 5-20 Hz.

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

[0017] Metal electrode deposition is performed on the amorphous gallium oxide film by ion beam sputtering, thermal evaporation or electron beam evaporation.

[0018] The flexible polymer substrate has a single edge size of 5-15 mm, and the electrode size is 1*0.7 mm. 2 .

[0019] An optoelectronic synapse device is prepared by the above preparation method, the amorphous gallium oxide film is formed on the flexible polymer substrate, and finally two symmetrical metal electrodes are formed on the amorphous gallium oxide film.

[0020] The preparation method of the flexible optoelectronic synapse device with data erasing function has the following beneficial effects:

[0021] Defects are generated in the material by bending the device, neutralizing ionized oxygen vacancies, thereby reducing the conductivity of the film to achieve data erasing, providing a method for quickly erasing data for metal oxide semiconductor-based optoelectronic synapse devices, and providing a new solution for erasing data for metal- semiconductor-metal structure metal oxide semiconductor-based optoelectronic synapse devices.

[0022] The flexible optoelectronic synapse device can highly simulate the function and behavior of biological synapses, has a storage bit width greater than 5 bits, and exhibits excellent performance. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The structure diagram of the flexible optoelectronic synapse device prepared by the present application;

[0024] Figure 2 Current-time curve of the flexible optoelectronic synapse device prepared by the present application under 254 nm light pulse stimulation for two times in succession;

[0025] Figure 3 PPF index of the flexible optoelectronic synapse device prepared by the present application as a function of pulse time interval and double exponential fitting curve diagram;

[0026] Figure 4 Current-time curve of the flexible optoelectronic synapse device prepared by the present application under 254 nm light pulse stimulation with different (a) pulse width, (b) pulse intensity, (c) and (d) pulse number.

[0027] Figure 5 Dark state current-voltage curve of the flexible optoelectronic synapse device prepared by the present application under different bending degrees;

[0028] Figure 6 254 nm light state current-voltage curve of the flexible optoelectronic synapse device prepared by the present application under different bending degrees;

[0029] Figure 7 Storage-erase cycle test diagram of the flexible optoelectronic synapse device prepared by the present application;

[0030] Figure 8 Optical response performance of the optoelectronic synapse device under different reaction pressures. DETAILED DESCRIPTION

[0031] A preparation method of a flexible optoelectronic synapse device with data erasing function, embodiment one, comprising the following steps:

[0032] Step one, a flexible polymer substrate (such as PET) with a size of 10x10mm 2 is sequentially ultrasonically cleaned in deionized water, anhydrous ethanol, acetone and isopropanol, each time for 10 minutes, and then blown dry with a dry nitrogen stream to obtain a clean PET substrate.

[0033] Step two, the clean PET substrate is transferred to a growth chamber, and the oxidation alloy is used as a target material. A turbo molecular pump is used to pump the pressure of the growth chamber to below 4x10 -5 Pa; during growth, the oxygen bottle switch is opened, the flow rate is adjusted to 20 sccm, and the plug valve is adjusted until the pressure in the growth chamber is 1-3 Pa, and a blue glow is generated in the growth chamber.

[0034] Among them, the growth chamber can adopt a low-pressure molecular beam epitaxy growth device (model LMBE 450) of Shenke Instrument.

[0035] Step three, at room temperature, using a pulse laser, with a wavelength of 355 nm, energy of 120 mJ / pulse, pulse width of 5 ns, frequency of 10 Hz, the target is burned for 60 min, thus completing the growth of amorphous gallium oxide film.

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

[0037] Metal oxide semiconductor material will inevitably produce a large number of oxygen vacancies in the growth process, resulting in the persistent photoconductivity (PPC) phenomenon of the device, which gives the device the ability to store optical information. The ionization of oxygen vacancies induced by light excitation is the intrinsic mechanism of the PPC effect of metal oxide semiconductor devices. The ionization of oxygen vacancies will release excess carriers and increase the conductivity of the film. The neutralization of oxygen vacancies needs to overcome an energy barrier, so the neutralization of oxygen vacancies is a relaxation process under natural conditions. Under the action of bending stress, slip planes will be generated in the material, and a large number of defects will be generated on the slip planes. These defects can act as recombination centers for ionized oxygen vacancies and electrons, promoting the neutralization of ionized oxygen vacancies and reducing the conductivity of the film. This is the basis for realizing the data erasing function by bending the device. Reference Figure 7 For example one, storage-erasing cycle test.

[0038] When the reactor pressure is adjusted to 4 Pa or above during the growth of amorphous gallium oxide, example two is obtained. As shown in Figure 8 The test found that the device of example two had large resistance and fast optical response characteristics, and did not have optoelectronic synapse characteristics.

[0039] As shown in Figure 5 The flexible optoelectronic synapse device provided has obvious differences in photocurrent under different bending degrees, and the reason is that the strain of the material 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 high-sensitivity optical auxiliary strain sensor.

Claims

1. A method for preparing a flexible optoelectronic synapse device with data erasing function, characterized in that, The method comprises the following steps: Step one, the pressure of the growth chamber is extracted to 4x10 -5 Pa, and oxygen is introduced to control the pressure of the growth chamber to 1-3 Pa; Step 2: at room temperature, the target is burned by a pulse 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 for 60 min, thus completing the growth of the amorphous gallium oxide film, and the amorphous gallium oxide film is grown on the flexible polymer substrate; Step 3: metal electrode deposition is performed on the amorphous gallium oxide film to form a metal electrode with symmetrical electrode material and electrode area, and a flexible optoelectronic synapse device with data erasing function is obtained, and data erasing is realized by bending the device.

2. The production method according to claim 1, wherein The flexible substrate is sequentially placed in deionized water, anhydrous ethanol, acetone and isopropanol for ultrasonic cleaning before use.

3. The preparation method according to claim 2, characterized in that, Each ultrasonic cleaning lasts for 5-15 minutes.

4. The method of claim 1 wherein the step of forming the first and second layers comprises the step of: Metal electrode deposition is performed on the amorphous gallium oxide film by ion beam sputtering, thermal evaporation or electron beam evaporation. ​ 5. The preparation method according to claim 1, characterized in that, Flexible polymer substrates with one side dimensions of 5-15 mm and electrode dimensions of 1 x 0.7 mm 2 .

6. A flexible optoelectronic synapse device with data erasing function, characterized in that, The method for preparing the flexible optoelectronic synapse device with data erasing function is prepared by the method of claim 1, comprising 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.

7. An optically assisted strain sensor, characterized in that The flexible optoelectronic synapse device with data erasing function is prepared by the method of claim 6.

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