A self-driven artificial tactile sensor array and its fabrication method

Abstract

This invention discloses a self-driven artificial tactile sensor array and its fabrication method, comprising: multiple arrayed units, each unit including a triboelectric nanogenerator and a synaptic transistor; the triboelectric nanogenerator includes a first substrate, a first friction layer, and a second friction layer, the first friction layer including a first branch and a second branch, the first branch being disposed on the first substrate, the second branch being disposed on the first branch, and the second branch being serrated; the synaptic transistor includes a second substrate, an active region, and a gate dielectric layer, the active region being disposed on the second substrate, the gate dielectric layer covering the exposed surface of the active region, and the gate dielectric layer being reused as the second friction layer of the triboelectric nanogenerator; wherein, the second branch of the first friction layer contacts and separates from the second friction layer to generate triboelectricity. This invention can realize self-driven bionic tactile function.

Description

Technical Field

[0001] This invention belongs to the field of communication technology, specifically relating to a self-driven artificial tactile sensor array and its fabrication method. Background Technology

[0002] In recent years, with the rapid development of artificial synaptic devices, researchers have achieved the organic integration of flexible sensors and artificial synaptic devices to simulate the function of biological neural synapses and apply them to the field of biomimetic sensing. This allows them to convert external stimuli (such as light, pressure, and smell) into electrical signals, enabling the system to respond to the external environment in a manner similar to that of biological sensory systems. This has led to a series of attractive research advances in artificial sensory systems such as tactile and visual sensing systems. Transistor-based synaptic biomimetic devices are increasingly prominent due to their good stability, controllable test parameters, and clearer operating mechanisms. Among them, double-layer synaptic transistors, where ions can move freely in the gate dielectric layer and migrate and accumulate under the induction of an electric field, thereby changing the channel conductivity, are particularly noteworthy. The gate electrode in the transistor can be considered as the presynaptic membrane, the channel layer as the postsynaptic membrane, and the channel conductance as the synaptic weight. This synaptic-like working mode holds promise for developing ultra-low-power artificial synaptic devices.

[0003] In 2012, Wang Zhonglin's team first proposed the triboelectric nanogenerator, which, utilizing the characteristics of triboelectric charging and charge transfer, possesses unique advantages in energy harvesting and sensing. By combining the triboelectric nanogenerator with a synaptic transistor, the triboelectric potential can not only act as a power source to drive the synaptic transistor but also link the spatiotemporal information generated by external mechanical stimuli with the output signal. This enables biomimetic applications in synaptic plasticity, logical functions, and artificial touch and neuromorphic learning through active, interactive, self-driven sensing. However, current self-driven tactile sensors present the triboelectric nanogenerator and synaptic transistor as two separate components. The triboelectric signal is simply interconnected with the transistor via wires, resulting in transmission loss and low efficiency. Furthermore, the separate fabrication processes for these two separate components are cumbersome and complex, failing to form a truly unified whole and still presenting limitations in device integration.

[0004] Therefore, there is an urgent need to develop a novel self-driven artificial tactile sensor array and its fabrication method to solve the above-mentioned technical problems. Summary of the Invention

[0005] To address the aforementioned problems in the prior art, this invention provides a self-driven artificial tactile sensor array and its fabrication method. The technical problem to be solved by this invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a self-driven artificial tactile sensor array, comprising: multiple arrayed units, wherein each unit is an integral assembly of a triboelectric nanogenerator and a synaptic transistor;

[0007] The triboelectric nanogenerator includes a first substrate, a first friction layer, and a second friction layer. The first friction layer includes a first branch and a second branch. The first branch is disposed on the first substrate, and the second branch is disposed on the first branch. The second branch is serrated.

[0008] The synaptic transistor includes a second substrate, an active region, and a gate dielectric layer. The active region is disposed on the second substrate, and the gate dielectric layer covers the exposed surface of the active region. The gate dielectric layer is reused as a second triboelectric layer for a triboelectric nanogenerator.

[0009] In this process, the second branch of the first friction layer comes into contact with and separates from the second friction layer, generating triboelectricity.

[0010] Secondly, the present invention also provides a method for fabricating a self-driven artificial tactile sensor array, comprising:

[0011] A tribological layer array is prepared, comprising multiple triboelectric nanogenerators arranged in an array. The triboelectric nanogenerator comprises a first substrate, a first tribological layer, and a second tribological layer. The first tribological layer comprises a first branch and a second branch. The first branch is disposed on the first substrate, and the second branch is disposed on the first branch. The second branch is serrated.

[0012] A synaptic transistor array is fabricated, comprising multiple synaptic transistors arranged in an array. Each synaptic transistor includes a second substrate, an active region, and a gate dielectric layer. The active region is disposed on the second substrate, and the gate dielectric layer covers the exposed surface of the active region. The gate dielectric layer is reused as a second friction layer for a triboelectric nanogenerator.

[0013] In this process, the second branch of the first friction layer comes into contact with and separates from the second friction layer, generating triboelectricity.

[0014] The beneficial effects of this invention are:

[0015] This invention provides a self-driven artificial tactile sensor array and its fabrication method, comprising 4×4 independent units composed of a triboelectric layer array and a synaptic transistor array. Each independent unit includes a triboelectric nanogenerator and a synaptic transistor. The self-driven artificial tactile sensor includes a flexible substrate, an active region formed on the substrate, and a source and drain formed on the active region, with the source, drain, and active region forming a whole. The whole is covered by a gate dielectric layer made of ionogel. The gate dielectric layer is reused as a second triboelectric layer for the triboelectric nanogenerator, and a first triboelectric layer consisting of the triboelectric nanogenerator is separated from the gate dielectric layer by a certain gap. The first triboelectric layer is attached to the flexible substrate that constitutes the triboelectric nanogenerator. A second branch of the first triboelectric layer contacts and separates from the second triboelectric layer, generating triboelectricity and affecting the conductivity characteristics of the active region. Structurally, the ionogel serves as the gate dielectric layer of the synaptic transistor, and the gate dielectric layer is reused as the second triboelectric layer of the triboelectric nanogenerator. This allows the triboelectric nanogenerator and the synaptic transistor to form a highly integrated unified structure. The first and second triboelectric layers in the triboelectric nanogenerator come into contact or separate to generate pulse voltages, forming corresponding induced charges in the active region and changing the conductivity characteristics of the active region. Synaptic currents are generated between the source and drain without external power supply, realizing self-driven bionic tactile functions. In terms of materials, the ionogel serves as the gate dielectric layer of the synaptic transistor, forming a double-layer structure at the gate dielectric layer / oxide semiconductor interface, generating a huge capacitance, thereby inducing extremely high carrier concentrations, enabling the synaptic transistor to operate at extremely low voltages.

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a self-driven artificial tactile sensor array provided in an embodiment of the present invention;

[0018] Figure 2 This is a schematic diagram of a unit provided in an embodiment of the present invention;

[0019] Figure 3 (a) is a schematic diagram of a first friction layer being a negative friction electrode sequence material provided in an embodiment of the present invention;

[0020] 3(b) is a schematic diagram of a first friction layer being a positive tribological electrode sequence material provided in an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of an equivalent circuit of a self-driven artificial synaptic transistor provided in an embodiment of the present invention;

[0022] Figure 5 This is a schematic diagram of the transfer characteristic curve of an indium oxide transistor provided in an embodiment of the present invention;

[0023] Figure 6 The transistor I provided in this embodiment of the invention d A diagram illustrating how things change over time. Detailed Implementation

[0024] The present invention will be further described in detail below with reference to specific embodiments, but the implementation of the present invention is not limited thereto.

[0025] In existing technologies, Professor Bao Zhenan's research group has fabricated a 2×3 array of flexible artificial synaptic sensors using distributed carbon nanotube pressure sensors, organic ring oscillators, and organic synaptic transistors. Pressure information is converted into input voltage signals for the synaptic transistors through coupling between the piezoresistive sensor and the ring oscillator, realizing artificial nerve fibers that sense minute mechanical movements. However, due to the low sensitivity of the piezoresistive sensor and its requirement for external power supply, and the fact that the three components of the system have different device structures and operating principles, resulting in different fabrication processes and independent functional device structures, it is difficult to fabricate highly integrated and sensitive array tactile sensors, severely limiting their application in human-computer interaction, intelligent sensing, and other fields.

[0026] Sun Qijun's team constructed an artificial tactile sensing device by combining a piezoelectric nanogenerator with an ion-gel-gated graphene transistor. The piezoelectric nanogenerator, acting as a self-powered mechanical sensor, converts external strain amplitude and frequency into specific pulse signals that are transmitted to the transistor gate, further modulating the charge carriers in the graphene channel. This piezoelectric artificial sensory neuron can mimic the biostimulation receptors, transmitting neurons, and synapses in the human sensory nervous system, enabling the perception, transmission, and processing of external stimuli. However, the tactile sensor implemented by combining a piezoelectric nanogenerator with a transistor requires a certain degree of deformation to activate, and has specific requirements for the frequency and amplitude of mechanical motion. Furthermore, the piezoelectric generator and transistor are simply interconnected by wires, resulting in transmission losses and low transmission efficiency. Moreover, the fabrication processes for the two parts are independent, making it difficult to fabricate highly integrated tactile sensor arrays.

[0027] In summary, (1) most current bionic tactile sensors are capacitive or piezoresistive sensors based on applied voltage. Both types of sensors are not sensitive to external mechanical changes and require external voltage to drive them, which greatly limits their working environment and practicality. Moreover, they require complex circuit design to match with synaptic transistors to achieve bionic tactile functions. (2) Triboelectric nanogenerators, as self-powered mechanical sensing devices, can directly convert external mechanical signals into electrical signals without power supply. However, as tactile sensors, their function is limited and there is a certain gap compared with bionic tactile sensors. At the same time, in the reported self-driven tactile sensors, triboelectric nanogenerators and synaptic transistors are two independent parts. The triboelectric signal is simply interconnected with the transistor through wires, resulting in transmission loss and low transmission efficiency. In addition, the fabrication processes of the functional units of the device are independent of each other and have not achieved a truly unified whole. There are still certain limitations in device integration.

[0028] To address the challenges of biomimetic tactile sensing, there is an urgent need to design a low-power, highly sensitive, and easily integrated artificial tactile sensor array. Specifically, based on a flexible substrate, the tactile sensor can better conform to the surface of a living organism, achieving conformal integration. The gate dielectric layer of the synaptic transistor is reused as a triboelectric layer for a nanogenerator, allowing triboelectricity to directly act on the synaptic transistor, forming a highly integrated unified structure with the triboelectric nanogenerator. The electrolyte serves as the gate dielectric layer, forming an electrical double-layer structure with the oxide semiconductor layer, generating a huge capacitance. This induces extremely high carrier concentration at the interface, enabling the transistor to operate normally at extremely low voltages. The active region and source / drain electrodes of the synaptic transistor are grown in situ using an in-situ growth process, continuously depositing different materials within the same cavity. This effectively improves the surface uniformity and purity of the materials, reduces the interfacial impedance between the electrodes and the active region, enhances the bonding force between the oxide semiconductor and the source / drain electrodes, improves the stability and lifespan of the device, simplifies the process flow, and avoids environmental pollution caused by process separation.

[0029] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of a self-driven artificial tactile sensor array provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of a unit provided in an embodiment of the present invention. The self-driven artificial tactile sensor array provided by the present invention includes: multiple array-arranged units 10, each unit 10 including a triboelectric nanogenerator 20 and a synaptic transistor 30;

[0030] The triboelectric nanogenerator 20 includes a first substrate 21, a first friction layer 22, and a second friction layer. The first friction layer 22 includes a first branch 22-1 and a second branch 22-2. The first branch 22-1 is disposed on the first substrate 21, and the second branch 22-2 is disposed on the first branch 22-1. The second branch 22-2 is serrated.

[0031] Synaptic transistor 30 includes a second substrate 31, an active region 32 and a gate dielectric layer 33. The active region 32 is disposed on the second substrate 31, and the gate dielectric layer 33 covers the exposed surface of the active region 32. The gate dielectric layer is reused as a second friction layer of a triboelectric nanogenerator.

[0032] In this process, the second branch 22-2 of the first friction layer 22 contacts and separates from the second friction layer, generating triboelectricity. It can be understood that the second branch of the first friction layer is serrated, which increases the contact area and thus the output voltage of the triboelectric nanogenerator.

[0033] In an optional embodiment of the present invention, the materials of the first substrate 21 and the second substrate 31 include any one of hydrogel (hyaluronic acid-dopamine gel), polyimide (PI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polydimethylsiloxane (PDMS), and polycarbonate (PC).

[0034] It should be noted that both the first and second substrates are flexible substrates, which makes it easier for the sensor fabricated in this embodiment to conform to the surface of an object and achieve conformal integration.

[0035] It is important to note that the first substrate 21 and the second substrate 31 are made of hydrogel, which allows the first substrate 21 and the second substrate 31 to adhere firmly to the surface of the object, making it easy to achieve conformal integration. In addition, the hydrogel is similar in properties to the extracellular matrix, has excellent biocompatibility, and also has high oxygen permeability and moisturizing properties, which can maintain the comfort of the wearing area for a long time and reduce dryness and hypoxia problems.

[0036] In an optional embodiment of the present invention, the material of the first friction layer 22 includes one of nylon, wool, silk, rubber, nitrile, copper foil, aluminum foil, polytetrafluoroethylene, polypropylene, polyethylene, polydimethylsiloxane, and polyimide.

[0037] In an optional embodiment of the present invention, the synaptic transistor 30 further includes an active region, a source, and a drain (not shown in the figure), the source and drain being located on the active region 32 and spaced apart.

[0038] The active region is made of any one of In2O3, IZO, IGO, or IGZO, and its thickness is 20–30 nm. The source and drain are made of the same material, including any one of aluminum, ITO, Au, Cr-Au, or Ti-Au, and their thicknesses are the same, ranging from 35 to 50 nm. The channel length between the source and drain is 60–200 μm, and its width is 800–6000 μm.

[0039] In an optional embodiment of the present invention, the material of the gate dielectric layer 33 includes one or more of the following: electrolyte solution, ionic liquid, ionic gel, ionic conductive polymer or proton conductive polymer.

[0040] Specifically, the self-driven artificial tactile sensor array provided in this embodiment includes a 4×4 independent unit 10 composed of a triboelectric layer array 40 and a synaptic transistor array 50. Each independent unit 10 includes a triboelectric nanogenerator 20 and a synaptic transistor 30. The self-driven artificial tactile sensor includes a flexible substrate, an active region 32 formed on the substrate, and a source and drain electrode (not shown in the figure) formed on the active region 32. The source, drain, and active region 32 form a whole. A gate dielectric layer 33 is integrally covered; the gate dielectric layer 33 is made of ionogel. The gate dielectric layer 33 is reused as a second triboelectric layer for the triboelectric nanogenerator. A certain gap is spaced between the gate dielectric layer 33 and the first triboelectric layer 22 constituting the triboelectric nanogenerator 20. The first triboelectric layer 22 is attached to the triboelectric nanogenerator 20. The generator 20 is mounted on a flexible substrate. Furthermore, an elastic medium is disposed around the flexible substrate of the triboelectric nanogenerator 20. This elastic medium is also disposed on the flexible substrate of the synaptic transistor 30, allowing the triboelectric nanogenerator 20 and the synaptic transistor 30 to be movably connected. Alternatively, the triboelectric nanogenerator 20 and the synaptic transistor 30 can be understood as moving relative to each other. They move closer together via the elastic medium, i.e., the second branch 22-2 of the first friction layer 22 contacts the second friction layer. They also move away from each other via the elastic medium, i.e., the second branch 22-2 of the first friction layer 22 separates from the second friction layer. This generates triboelectricity, affecting the conductivity of the active region 32. The elastic medium can be any one of spring, rubber, silicone, or elastic fiber. In this structure, ion gel serves as the gate dielectric layer 33 of the synaptic transistor and the second friction layer of the triboelectric nanogenerator 20, thus organically combining the triboelectric nanogenerator 20 with the synaptic transistor 30. This structure is simple, lightweight, and flexible. When the first friction layer 22 and the second friction layer come into contact and separate, a pulse voltage is generated, forming a corresponding induced charge in the active region 32. This alters the conductivity of the active region 32, allowing synaptic current to flow between the source and drain without external power supply, thus achieving a self-driven bionic tactile function.

[0041] It should be noted that, Figure 1The illustrated embodiment only schematically shows the positional relationship between the friction layer array and the synaptic transistor array, and does not represent the actual dimensions. Figure 2 The embodiments shown are only schematic representations of the positional relationships of the various film layers included in the unit and do not represent their actual dimensions.

[0042] Based on the same inventive concept, such as Figure 3 As shown, Figure 3 (a) is a schematic diagram of a first friction layer being a negative friction electrode sequence material provided in an embodiment of the present invention; (b) is a schematic diagram of a first friction layer being a positive friction electrode sequence material provided in an embodiment of the present invention. The present invention also provides a method for preparing a self-driven artificial tactile sensor array, used to prepare the self-driven artificial tactile sensor array provided in the above embodiments of the present invention. For embodiments of the self-driven artificial tactile sensor array, please refer to the above description, which will not be repeated here; please continue to refer to... Figure 1 and Figure 2 As shown, the preparation method includes:

[0043] A friction layer array 40 is fabricated. The first friction layer 22 array includes multiple arrays of triboelectric nanogenerators 20. The triboelectric nanogenerator 20 includes a first substrate 21, a first friction layer 22, and a second friction layer. The first friction layer 22 includes a first branch 22-1 and a second branch 22-2. The first branch 22-1 is disposed on the first substrate 21, and the second branch 22-2 is disposed on the first branch 22-1. The second branch 22-2 is serrated.

[0044] A synaptic transistor array 50 is fabricated, which includes a plurality of synaptic transistors 30 arranged in an array. Each synaptic transistor 30 includes a second substrate 31, an active region 32, and a gate dielectric layer 33. The active region 32 is disposed on the second substrate 31, and the gate dielectric layer 33 covers the exposed surface of the active region 32. The gate dielectric layer is reused as a second friction layer of a triboelectric nanogenerator.

[0045] In this process, the second branch 22-2 of the first friction layer 22 comes into contact with and separates from the second friction layer, generating triboelectricity.

[0046] In an optional embodiment of the present invention, the fabrication process of the triboelectric nanogenerator 20 includes:

[0047] The surface of the first substrate 21 is ultrasonically cleaned using organic solvents and deionized water respectively to remove organic contaminants adhering to the surface of the first substrate 21. The thickness of the first substrate 21 is 150 μm. The organic solvents can be acetone or isopropanol.

[0048] Polydimethylsiloxane (PDMS) and curing agent were mixed in a mass ratio of 10:1 and stirred for 20 minutes. The mixture was then degassed under vacuum for 20 minutes to remove air bubbles, thus forming a mixture.

[0049] The mixture was spin-coated on a serrated groove mold at 500 rpm for 60 s, and then heat-cured at 85°C for 1 hour. After that, the mixture was peeled off to obtain a first friction layer 22 with a serrated surface microstructure. The serrated surface microstructure has a height of 5 μm and a bottom square side length of 5 μm. The height of the serrated surface microstructure refers to the dimension along the direction perpendicular to the first substrate 21.

[0050] The first friction layer 22 is prepared on the first substrate 21.

[0051] In an optional embodiment of the present invention, the fabrication process of the synaptic transistor 30 includes:

[0052] The surface of the second substrate 31 is ultrasonically cleaned using organic solvents and deionized water respectively to remove organic contaminants adhering to the surface of the second substrate 31. The thickness of the second substrate 31 is 150 μm. The organic solvents can be acetone or isopropanol.

[0053] An active region 32 with a thickness of 25 nm was deposited on the surface of the second substrate 31 using an RF magnetron sputtering system. The active region 32 was made of indium oxide (In2O3). During magnetron sputtering, the RF power was 100 W, the sputtering pressure in the cavity was 0.3 Pa, the sputtering gas was argon, the argon flow rate was 30 sccm, and the deposition rate was 2.5 nm / min.

[0054] A 40 nm thick layer of ITO (In2O3:SnO2 = 90:10 wt%) was deposited on the upper surface of the active region 32 using an RF magnetron sputtering system to form the source and drain electrodes, respectively. The channel between the source and drain electrodes was 125 μm long and 1600 μm wide. During magnetron sputtering, the ignition pressure was 2 Pa, the RF power was 50 W, the sputtering gas pressure inside the cavity was 0.65 Pa, the sputtering gas was argon, the argon flow rate was 20 sccm, and the deposition rate was 7 nm / min.

[0055] The ionic liquid 1-ethyl-3-methylimidazoline bis(trifluoromethanesulfonyl)imine [(EMI)(TFSA)] was dried in a vacuum drying oven at 70°C for 24 h. Polyvinylidene fluoride-hexafluoropropylene [P(VDF-HFP)], the ionic liquid [(EMI)(TFSA)], and acetone were mixed in a mass ratio of 1:4:7 and stirred at 50°C and 500 rpm for about 4 hours using a magnetically heated stirrer to obtain an ion gel precursor solution. The ion gel precursor solution was then screen-printed onto the active region 32, the source electrode, and the drain electrode to form a gate dielectric layer. This gate dielectric layer was reused as the second friction layer of the triboelectric nanogenerator.

[0056] Specifically, in this embodiment, please continue to refer to Figure 3 A self-driven artificial tactile sensor composed of a triboelectric nanogenerator 20 and a synaptic transistor 30 is described. The ion gel gate dielectric layer 33 is reused as the second friction layer of the triboelectric nanogenerator. The second friction layer and the upper first friction layer 22 form a triboelectric nanogenerator 20. When the interfaces of the first friction layer 22 and the second friction layer come into contact, due to the different attraction abilities of different materials for electrons, opposite charges are induced on both sides of the interface. Figure 3 As shown in (a), when the first tribological layer 22 is a negative tribological electrode sequence material, due to the principle of electrostatic induction, the ion gel gate dielectric layer 33 will induce a positive charge. When the gap in the middle of the triboelectric nanogenerator 20 changes, there is a potential difference between the surface charge and the interior of the ion gel, causing ions in the electrolyte to migrate. Oriented positive ions appear at the interface between the ion gel gate dielectric layer 33 and the semiconductor layer, which is equivalent to providing a positive gate voltage for the In2O3 semiconductor layer, causing the Fermi level of In2O3 to rise. Figure 3 As shown in (b), when the first friction layer 22 is a positive friction electrode sequence material, due to the principle of electrostatic induction, the ion gel gate dielectric layer 33 will induce a negative charge. A potential difference exists between the surface charge and the interior of the ion gel, causing ions in the electrolyte to migrate. Directed negative ions appear at the interface between the ion gel gate dielectric layer 33 and the semiconductor layer, which is equivalent to providing a negative gate voltage to the In2O3 semiconductor layer, causing the Fermi level of In2O3 to decrease. Since the ion gel serves as the gate dielectric layer 33, the ion concentration and distribution within it are controlled by the gate voltage, thereby regulating the transistor's conductivity. This regulation is similar to the neurotransmitter release and receptor binding process in biological synapses, thus achieving a function similar to that of biological synapses.

[0057] In an optional embodiment of the present invention, the growth of the active region 32 and the deposition of the source and drain electrodes on the upper surface of the active region 32 are both carried out using in-situ growth technology, and different materials are continuously deposited in the same cavity.

[0058] Specifically, in this embodiment, the active region 32, source electrode, and drain electrode of the synaptic transistor are all fabricated using an in-situ growth process. On the one hand, the same measurement and control sputtering process is used to continuously deposit different materials in the same cavity, simplifying the process flow while avoiding environmental pollution caused by process separation. On the other hand, the in-situ growth process can improve the uniformity and purity of the material surface, reduce the interface impedance between the electrode and the active region, enhance the bonding force between the oxide semiconductor and the source and drain electrodes, and improve the stability and lifespan of the device.

[0059] The in-situ growth process for fabricating the active region, source, and drain is as follows:

[0060] S1. Equipment Start-up and Sample Loading: Start the cold water chamber and main power supply, open the nitrogen inlet valve, and wait for the internal pressure to reach 10... 5 Pa, close the air inlet valve, and place the sample in.

[0061] S2. Sequentially start the mechanical pump and molecular pump to create a vacuum, raising the internal pressure to 10. -4 Pa.

[0062] S3. Growth of indium oxide in the active region: Select indium oxide target, preheat RF source, and adjust ignition pressure; set argon flow rate to 30 sccm, and adjust gate valve to make the internal pressure of the chamber approximately 2 Pa; open target baffle, turn on RF power to ignite, and observe glow discharge phenomenon inside the chamber; set power to 100W, and adjust gate valve to reduce chamber pressure to 0.3 Pa; start sample stage rotation for indium oxide pre-sputtering for 5 minutes to clean target surface and ensure uniform deposition; after pre-sputtering, open sample baffle for formal indium oxide sputtering for 10 minutes to ensure uniformity and thickness of the active region film; after sputtering, close sample baffle, stop argon flow, stop sample stage rotation, and turn off RF source.

[0063] S4. Replace the target and mask in situ; while maintaining the cavity vacuum, use the target rotation mechanism to switch from the indium oxide target to the ITO (indium tin oxide) target for source and drain deposition; within the cavity, use the automatic mask switching system to replace the mask used for the active region with the source and drain masks to ensure that the deposition is in the correct position.

[0064] S5. In-situ growth of ITO at the source and drain; preheat the RF source and adjust the ignition pressure; set the argon flow rate to 20 sccm and adjust the gate valve to make the internal pressure of the chamber 2 Pa; open the target baffle and start the RF power supply; set the RF power supply power to 50W and adjust the gate valve to reduce the chamber pressure to 0.65 Pa, and begin the deposition of ITO at the source and drain; start the sample stage rotation for ITO pre-sputtering for 5 min to remove possible oxide layers or contaminants on the target surface; after pre-sputtering, open the sample baffle and perform formal ITO sputtering for 7 min to ensure the uniformity and sufficient conductivity of the film; after sputtering, close the sample baffle, set the argon flow rate to 0, stop the sample stage rotation, and turn off the RF source.

[0065] S6. Close the argon pressure reducing valve and the inlet valve; open the gate valve and evacuate for 5 minutes; after evacuation is complete, close the gate valve, gradually reduce the system pressure, stop the molecular pump, and after it has completely stopped, close the fore-stage valve and the mechanical pump in sequence, and inject protective gas pressure for sampling.

[0066] In an optional embodiment of the present invention, please refer to Figures 4-6 , Figure 4 This is a schematic diagram of an equivalent circuit of a self-driven artificial synaptic transistor provided in an embodiment of the present invention. Figure 5 This is a schematic diagram of the transfer characteristic curve of the indium oxide synaptic transistor provided in an embodiment of the present invention. Figure 6 The indium oxide synaptic transistor I provided in this embodiment of the invention d A diagram illustrating how it changes over time, from Figure 5 As can be seen, the curve exhibits a parabolic shape, with the source-drain voltage fixed at 0.5V and the gate voltage cycling from -5V to 2V. Due to the charge trapping effect, the transistor's transfer curve forms a storage window. Figure 6 This demonstrates the process of transistor I reciprocatingly contacting and separating from the first friction layer 22 and the ion-gel gate dielectric layer 33 on a PET substrate. d The curve showing the change of source-drain voltage V over time, where V is the source-drain voltage V. ds =0.5V, by Figure 6 It can be seen that when the contact separation frequency is low, I d It stabilizes over time; as the frequency increases, I... d I increases steadily over time when no contact separation is performed. d It remains stable and unchanged.

[0067] In summary, the self-driven artificial tactile sensor array and its fabrication method provided by this invention have the following beneficial effects:

[0068] 1. A triboelectric nanogenerator 20 and a synaptic transistor 30 are ingeniously combined, with the gate dielectric layer directly reused from the nanogenerator's triboelectric layer, forming a highly integrated unified structure. The triboelectric nanogenerator 20, acting as a sensor, collects external tactile information, exhibiting higher sensitivity and simpler operation compared to traditional piezoresistive and capacitive sensors. The triboelectric nanogenerator 20 converts mechanical signals into electrical pulse signals, which are then input into the synaptic transistor 30, generating a synaptic current between the source and drain electrodes. This allows for the fabrication of a low-power, highly sensitive, integrated artificial bionic tactile sensor.

[0069] 2. Ion gel, acting as the gate dielectric layer 33, forms an electric double layer structure at the interface, generating a huge capacitance. This induces extremely high carrier concentrations on the oxide semiconductor surface, enabling the synaptic transistor to operate at extremely low voltages (V). dsIt operates at 0.1V. At the same time, the ion gel, as the gate dielectric layer 33, also serves as the second friction layer of the triboelectric nanogenerator 20, realizing a true organic combination of the triboelectric nanogenerator 20 and the synaptic transistor 30. By changing the material of the first friction layer 22, the gate voltage is directly generated by friction on the ion gel dielectric layer, further regulating the transistor output characteristics. It has the advantages of simple structure, easy integration, low power consumption, and low latency.

[0070] 3. The ion gel serves as the gate dielectric layer 33, where the ion concentration and distribution are controlled by the gate voltage, thereby regulating the conductivity of the transistor. This regulation is similar to the neurotransmitter release and receptor binding process in biological synapses, thus enabling the realization of biomimetic synapse functions.

[0071] 4. The active region and source and drain electrodes of the synaptic transistor are grown in situ using an in-situ growth process, in which different materials are deposited continuously in the same cavity. This effectively improves the uniformity and purity of the material surface, reduces the interface impedance between the electrode and the active region, enhances the bonding force between the oxide semiconductor and the source and drain electrodes, improves the stability and lifespan of the device, simplifies the process flow, and avoids environmental pollution caused by process separation.

[0072] 5. Using hydrogel polymer as a flexible substrate, it can firmly adhere to the surface of the object and easily achieve conformal integration. In addition, the hydrogel is similar in properties to the extracellular matrix, with excellent biocompatibility. It also has high oxygen permeability and moisturizing properties, which can maintain the comfort of the wearing area for a long time and reduce dryness and hypoxia problems.

[0073] 6. The first friction layer 22 has a serrated surface microstructure, which increases the contact area and enhances the output voltage of the triboelectric nanogenerator 20.

[0074] 7. An artificial tactile sensor based on a triboelectric nanogenerator 20, wherein the first triboelectric layer 22 comprises a material with a positive triboelectric electrode sequence, such as nylon, wool, silk, rubber, nitrile, copper foil, or aluminum foil; and a material with a negative triboelectric electrode sequence, including polytetrafluoroethylene, polypropylene, polyethylene, polydimethylsiloxane, or polyimide.

[0075] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion, such that an article or device comprising a list of elements includes not only those elements but also other elements not expressly listed. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device comprising said element. Terms such as "connected" or "linked" are not limited to physical or mechanical connections but can include electrical connections, whether direct or indirect. The orientations or positional relationships indicated by terms such as "upper," "lower," "left," and "right" are based on the orientations or positional relationships shown in the accompanying drawings and are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as limiting the invention.

[0076] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, those skilled in the art can combine and integrate the different embodiments or examples described in this specification.

[0077] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. A self-driven artificial tactile sensor array, characterized in that, include: Multiple arrays of units, each unit including a triboelectric nanogenerator and a synaptic transistor; The triboelectric nanogenerator includes a first substrate, a first friction layer, and a second friction layer. The first friction layer includes a first branch and a second branch. The first branch is disposed on the first substrate, and the second branch is disposed on the first branch. The second branch is serrated. The material of the first friction layer includes any one of nylon, wool, silk, rubber, nitrile, copper foil, aluminum foil, polytetrafluoroethylene, polypropylene, polyethylene, polydimethylsiloxane, and polyimide. The synaptic transistor includes a second substrate, an active region, and a gate dielectric layer. The active region is disposed on the second substrate, and the gate dielectric layer covers the exposed surface of the active region. The gate dielectric layer is reused as the second triboelectric layer of the triboelectric nanogenerator. The material of the gate dielectric layer includes one or more of electrolyte solution, ionic liquid, ionic gel, ion-conducting polymer, or proton-conducting polymer. In this process, the second branch of the first friction layer comes into contact with and separates from the second friction layer, generating triboelectricity. The synaptic transistor further includes an active region, a source, and a drain, wherein the source and the drain are located on the active region and are spaced apart. The active region is made of any one of In2O3, IZO, IGO, and IGZO, and its thickness is 20-30 nm. The source and drain are made of the same material, including any one of aluminum, ITO, Au, Cr-Au, and Ti-Au, and their thicknesses are the same, ranging from 35 to 50 nm. The channel between the source and drain has a length of 60-200 μm and a width of 800-6000 μm.

2. The self-driven artificial tactile sensor array according to claim 1, characterized in that, The materials of the first substrate and the second substrate include any one of hydrogel, polyimide, polyethylene naphthalate, polyethylene terephthalate, polydimethylsiloxane, and polycarbonate.

3. A method for fabricating a self-driven artificial tactile sensor array, used to fabricate the self-driven artificial tactile sensor array as described in any one of claims 1 to 2, characterized in that, include: A triboelectric layer array is fabricated, comprising multiple triboelectric nanogenerators arranged in an array. Each triboelectric nanogenerator includes a first substrate, a first triboelectric layer, and a second triboelectric layer. The first triboelectric layer includes a first branch and a second branch. The first branch is disposed on the first substrate, and the second branch is disposed on the first branch. The second branch is serrated. The fabrication process of the triboelectric nanogenerator includes: The surface of the first substrate was ultrasonically cleaned using organic solvents and deionized water, respectively, to remove organic contaminants adhering to the surface of the first substrate. The material used to form the first friction layer is mixed with a curing agent in a preset mass ratio and stirred, and then degassed under vacuum to remove air bubbles, forming a mixture. The mixture is spin-coated onto a serrated groove mold at a preset speed, and after being thermo-cured at a preset temperature, it is peeled off to obtain a first friction layer with a serrated surface microstructure, wherein the height of the serrated surface microstructure is 4~6 μm and the side length of the bottom square is 4~6 μm. The first friction layer is prepared on the first substrate; A synaptic transistor array is fabricated, comprising a plurality of synaptic transistors arranged in an array. Each synaptic transistor includes a second substrate, an active region, and a gate dielectric layer. The active region is disposed on the second substrate, and the gate dielectric layer covers the exposed surface of the active region. The gate dielectric layer is reused as the second triboelectric layer of the triboelectric nanogenerator. The fabrication process of the synaptic transistor includes: The surface of the second substrate was ultrasonically cleaned using organic solvents and deionized water, respectively, to remove organic contaminants adhering to the surface of the second substrate. A radio frequency magnetron sputtering system is used to deposit a material of a specific shape on the surface of the second substrate to form an active region. During the magnetron sputtering process, one or more of In2O3, ZnO, and Ga2O3 are selected as sputtering targets, argon is used as an inert carrier gas, the sputtering power is 50~100 W, the sputtering pressure is 0.3~0.5 Pa, and the deposition rate is 2~6 nm / min. A radio frequency magnetron sputtering system is used to deposit materials for forming the source and drain on the upper surface of the active region. During the magnetron sputtering process, one or more of aluminum, ITO, Au, Cr, and Ti are selected as sputtering targets, argon is used as an inert carrier gas, the sputtering power is 50~100 W, the sputtering pressure is 0.5~0.7 Pa, and the deposition rate is 6~8 nm / min. The material used to form the gate dielectric layer is mixed with the corresponding solvent in a preset mass ratio and stirred using a magnetic heating stirrer to obtain a precursor solution. The precursor solution is then applied to the active region, the source electrode, and the drain electrode by screen printing, spin coating, or dropper transfer to form the gate dielectric layer. The gate dielectric layer is reused as the second friction layer of the triboelectric nanogenerator. In this process, the growth of the active region and the deposition of the source and drain electrodes on the upper surface of the active region are both carried out using in-situ growth technology, and different materials are continuously deposited in the same cavity. In this process, the second branch of the first friction layer comes into contact with and separates from the second friction layer, generating triboelectricity.

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