This application is based upon and claims priority to Chinese Patent Application No. 201811367908.0, filed on Nov. 16, 2018, the entire contents of which are incorporated herein by reference.
The present invention relates to the technical field of neuro-bionic devices, in particular to a neuro-bionic device based on a two-dimensional Ti3C2 material and a preparation method thereof.
In traditional electronic computers, the bottleneck caused by Von Neumann architecture is the separation of a computing module from a storage module. This makes CPU read data from the storage module, and then process the data when executing a command, which results in excessive consumption of time and power for reading the data. In the face of this serious problem, previous studies found that the human brain had solved the problem. Because of the inherent fusion between storage and computing, interconnected neurons in the human brain can effectively handle complex tasks. Therefore, in order to simulate the characteristics of the brain, academia and industry personnel are exploring systems similar to the human brain. Thus, a non-conventional device is required for realizing an information storage and processing different from that of the Von Neumann architecture.
Memristor is a kind of non-linear resistor with a memory function, and is a device capable of simulating the brain and simulating to realize artificial synapses after extensive research. The memristor has an excellent data processing capability far superior than that of the current digital architecture. Moreover, the memristor can better simulate and calculate information on a biological scale. Currently, there are some reports on the memristor, i.e., a kind of synaptic bionic device. However, the bionic effect of the memristor is not ideal as per expectation, especially, when the pulse width is reduced to a predetermined degree, the memristor is hard to be turned on for regulation. Therefore, it is of great significance to develop an ultrafast synaptic bionic device with a simple structure and a good bionic effect.
Two-dimensional materials have many unique properties, touching off a research upsurge. Due to the potential application of two-dimensional layered materials in the fields such as electrochemistry, researchers have been looking for new two-dimensional layered materials. In 2011, Naguib. M and other researchers used hydrofluoric acid to etch Ti3AlC2Tx to remove the Al therein, thus forming a novel two-dimensional metal carbide known as Ti3C2Tx. At present, there is no report on the application of Ti3C2 material in the preparation of synaptic bionic device with a relatively good bionic effect.
The first objective of the present invention is to provide a neuro-bionic device based on a two-dimensional Ti3C2 material, so as to solve the problem that the bionic effect of the existing device is not satisfactory.
The second objective of present invention is to provide a method of preparing a neuro-bionic device based on a two-dimensional Ti3C2 material.
The first objective of the present invention is realized as follows. A neuro-bionic device includes a Pt/Ti/SiO2/Si substrate, a neuro-bionic layer formed on a Pt film layer of the Pt/Ti/SiO2/Si substrate, and an Al electrode layer formed on the neuro-bionic layer. The neuro-bionic layer is made of a two-dimensional Ti3C2 material.
The neuro-bionic layer is prepared by a drop-coating method, and a thickness of the neuro-bionic layer is 5 nm-200 nm.
The Al electrode layer is prepared by an evaporation method, and the Al electrode layer includes a plurality of circular electrodes with a diameter of 80 μm-300 μm uniformly distributed on the neuro-bionic layer.
A thickness of each circular electrode is 50 nm-200 nm.
The Pt/Ti/SiO2/Si substrate includes a Si layer, a SiO2 layer, a Ti layer and a Pt layer from bottom to top.
The neuro-bionic device can be an electronic artificial synapse device.
The second objective of the present invention is realized as follows. A method of preparing a neuro-bionic device includes the following steps:
In the step d, a thickness of the neuro-bionic layer is about 5 nm to 200 nm.
In the step e, circular holes with a diameter of 80 μm-300 μm are uniformly arranged on the mask, and a thickness of the Al electrode layer is 50 nm -200 nm.
In the step e, the evaporation bombardment voltage is slowly increased until a reading of an ammeter is 50 A for an evaporation coating.
In the present invention, a specific Al electrode layer is used to simulate a pre-synaptic membrane of a synapse, a Pt film layer is used to simulate a post-synaptic membrane of the synapse, and a corresponding Ti3C2 material is used as a neuro-bionic layer, so that two basic functions of the synapse (spike-timing-dependent plasticity and paired pulse facilitation) are simulated, and the bionic effect is good.
The resistance of the neuro-bionic device of the present invention can be controlled by applying a series of pulse sequences with different amplitudes and widths. The resistance change of the neuro-bionic device of the present invention can be controlled by applying pulses of different directions. Moreover, the neuro-bionic device of the present invention has stability and repeatability. The pulse amplitude can be reduced to 2 V, and the resistance of device can be continuously modulated under a series of pulse sequences with a pulse width and interval of 10 ns, which has a great importance to the application of ultrafast neural modulation.
As shown in
The neuro-bionic layer 2 is a two-dimensional Ti3C2 material with a thickness of 150 nm.
The Al electrode layer 3 includes a plurality of uniformly distributed circular electrodes with a diameter of 90 μm, and a thickness of each circular electrode is 150 nm.
The method of preparing the neuro-bionic device shown in
(1) forming a neuro-bionic layer on a Pt/Ti/SiO2/Si substrate
{circle around (1)} the Pt/Ti/SiO2/Si substrate is washed with acetone under an ultrasonic wave for 10 minutes, put into alcohol for an ultrasonic washing for 10 minutes, put into deionized water using a tweezer for an ultrasonic washing for 5 minutes, and finally placed on a dustless test paper and dried with nitrogen for storage;
{circle around (2)} prepared Ti3C2 powder is dissolved in deionized water at a concentration of 5 mg/mL for shaking evenly, and then dissociated by the ultrasound wave for 30 minutes;
{circle around (3)} a solution after an ultrasonic treatment is taken out, and rinsed with nitrogen for sealing;
{circle around (4)} the solution is taken using a pasteur pipette, and drop coated on a Pt film layer of the Pt/Ti/SiO2/Si substrate, and the Pt/Ti/SiO2/Si substrate is placed overnight in a closed space filled with nitrogen to form the neuro-bionic layer with a thickness of 150 nm;
(2) preparing an Al electrode on the neuro-bionic layer
{circle around (1)} as shown in
{circle around (2)} a bell jar pressure and a system pressure of the evaporation coating machine is adjusted to 1.5 Pa by a mechanical pump, then the mechanical pump is converted into a diffusion pump state for a preheating for 60 minutes, and after the preheating, the bell jar pressure is adjusted to 3×10−3 Pa;
{circle around (3)} when a vacuum degree reaches 3×10−3 Pa, the evaporation coating machine is adjusted to an evaporation state, and a workpiece is rotated;
{circle around (4)} an evaporation bombardment voltage is increased slowly, when a reading of an evaporation bombardment ammeter is 50 A, an evaporation coating is performed to obtain the Al electrode having a thickness of 150 nm.
The Al electrode layer is replaced by the Au electrode layer, and other parameters and preparation methods remain unchanged. The neuro-bionic device with the top layer of Au electrode layer is obtained.
The performance of the devices in Embodiment 1 and contrast example 1 are tested respectively.
As shown in
Al electrode layer of the neuro-bionic device in Embodiment 1 of the present invention. The voltage is increased from 0 V to 6 V, and then gradually reduced to 0 V, then, the voltage changes from 0 V to −6 V, and then changes gradually to 0 V. When the scanning voltage reaches about 4 V, the device suddenly changes from a high-resistance state to a low-resistance state. At this time, the resistance value of the neuro-bionic device remains at the low-resistance state. When the negative voltage applied on the Al electrode layer is increased to −4 V, the neuro-bionic device suddenly changes from the low-resistance state to the high-resistance state, and the device remains at the high-resistance state until the scanning voltage returns to 0 V.
As shown in
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The same pulse test is performed on the neuro-bionic device of Embodiment 1, as shown in
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Number | Date | Country | Kind |
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201811367908.0 | Nov 2018 | CN | national |