Flexible pressure sensor integrated with carbon nanotube transistor and preparation method

Abstract

The invention provides a flexible pressure sensor integrated with a carbon nanotube transistor, which comprises an elastomer composite gate electrode, a layered composite dielectric layer and a floating gate carbon nanotube transistor, and is characterized in that the elastomer composite gate electrode is formed by compounding an elastomer electrode and a metal electrode; the elastomer electrode is prepared from polydimethylsiloxane and a conductive carbon nanotube, a multi-scale microstructure is formed on the outer surface of the elastomer electrode, and the metal electrode comprises a lower metal layer electrode evaporated on the outer surface of the microstructure and an upper metal layer electrode connected with the upper surface of the elastomer electrode; the layered composite dielectric substance layer is formed by compounding an organic dielectric substance and an inorganic dielectric substance; the length of a floating gate electrode in the floating gate carbon nanotube transistor is prolonged for integration with other parts, and a channel of the floating gate electrode is made of a high-purity semiconductor carbon nanotube film. According to the invention, the working voltage is relatively low, the sensing performance is relatively high, the design flexibility is relatively high, the electrical and mechanical stability is relatively high, and miniaturization and large-scale production of sensor devices are facilitated.

Description

Technical Field

[0001] The present invention relates to the field of pressure sensors, and in particular to a flexible pressure sensor integrated with a carbon nanotube transistor and a preparation method thereof. Background Art

[0002] Transistor-integrated flexible pressure sensors are a new type of mechanically flexible sensor device that integrates transistor electronic circuits with sensitive elements. They can convert pressure signals into electrical changes, such as current or voltage, and then detect external pressure signals. Compared with other types of sensors, transistor-integrated pressure sensors have the characteristics of low power consumption, small device size, and the ability to directly convert pressure signals into electrical signals such as current or voltage that are easy to process. They have broad application prospects in the fields of neural prostheses, intelligent robots, and wearable and implantable health electronic medical care. However, the existing typical transistor-integrated flexible pressure sensors have problems such as relatively high operating voltage, relatively low sensing performance, and relatively poor mechanical and electrical stability.

[0003] The existing transistor-integrated flexible pressure sensor design includes a typical design that integrates a microstructured elastomeric dielectric mechanical sensitive element with an organic semiconductor thin film transistor. This integrated design method, on the one hand, has a relatively weak electrostatic regulation ability due to the relatively thick microstructured elastomeric dielectric and a relatively low dielectric constant, and requires a large gate voltage to make limited adjustments to the source-drain current, that is, the sensing performance is relatively limited; on the other hand, organic semiconductor thin film transistors usually have relatively poor electrical properties, such as low carrier mobility, and also require transistors to work at a relatively large voltage to effectively convert the capacitance change caused by pressure. At the same time, the electrical properties of organic semiconductor transistor thin film devices are prone to further deterioration over time, and the organic semiconductor transistor preparation process is difficult to match the existing photolithography process, and there are also many problems in device miniaturization and scale. In addition, the integration method of transistors in existing design schemes is usually to directly laminate the microstructure of the mechanical sensitive element on the semiconductor film, which easily causes the semiconductor film to be damaged by the microstructure mechanics. Summary of the invention

[0004] The present invention solves the problems of existing transistor-integrated flexible pressure sensors, such as high operating voltage, low sensing performance, difficulty in miniaturization and scale-up, and easy damage of semiconductor films by mechanical effects. A flexible pressure sensor with integrated carbon nanotube transistors and a preparation method are provided to solve the above problems.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention provides a flexible pressure sensor with integrated carbon nanotube transistor, comprising an elastomeric composite gate electrode, a layered composite dielectric layer, and a floating gate carbon nanotube transistor, wherein the elastomeric composite gate electrode is composited by an elastomeric electrode and a metal electrode, the elastomeric electrode is an elastomer prepared from a composite material of polydimethylsiloxane and conductive carbon nanotubes, the elastomeric electrode forms a multi-scale microstructure on the outer surface facing the layered composite dielectric, the metal electrode is a lower metal layer electrode evaporated on the outer surface of the elastomeric electrode with the multi-scale microstructure and an upper metal layer electrode connected to the surface of the elastomeric electrode without the multi-scale microstructure; the layered composite dielectric layer is composed of an organic dielectric and an inorganic metal The oxide dielectric forms a composite of an upper and lower structure, which is located between the outer surface of the elastomer composite gate electrode with a multi-scale microstructure and the floating gate in the floating gate carbon nanotube transistor; the floating gate electrode in the floating gate carbon nanotube transistor is extended in length for integration with the elastomer composite gate electrode and the layered composite dielectric layer, the length of the extended section is greater than the length of the elastomer composite gate electrode and the layered composite dielectric layer, the upper surface of the extended section is connected to the inorganic metal oxide dielectric in the layered composite dielectric layer, and the upper surface of the non-extended section is deposited in order from bottom to top: a transistor dielectric layer, a channel, and a source electrode and a drain electrode located at both ends of the channel, and the channel is made of a high-purity semiconductor carbon nanotube film.

[0007] Preferably, the method for preparing the elastomeric electrode from the polydimethylsiloxane and conductive carbon nanocomposite material is: mixing polydimethylsiloxane with a n-hexane solution, dispersing the conductive carbon nanotubes in isopropanol by water bath ultrasound, and finally mixing the two mixed solutions.

[0008] Preferably, the ratio of the polydimethylsiloxane to the n-hexane solution is 1:5-1:10, the ratio of the conductive carbon nanotubes to isopropyl alcohol is 1:200, and the ratio of the polydimethylsiloxane to the conductive carbon nanotubes is 100:1-100:5.

[0009] Preferably, the multi-scale microstructure is a plurality of irregular three-dimensional structures or a plurality of micro-pyramid structures of different sizes.

[0010] Preferably, the metal electrode is made of titanium-gold alloy or chromium-gold alloy by electron beam or thermal evaporation, the thickness of the titanium or chromium is 5 nm, and the thickness of the gold is 50 nm.

[0011] Preferably, the organic dielectric in the layered composite dielectric layer is polyparaxylene or polyimide, with a thickness of less than 200 nm, and the inorganic metal oxide dielectric is hafnium oxide, with a thickness of 10-20 nm.

[0012] Preferably, the transistor dielectric layer in the floating gate carbon nanotube transistor is hafnium oxide with a thickness of 10-20 nm.

[0013] The present invention also provides a method for preparing the above-mentioned flexible pressure sensor integrated with carbon nanotube transistors, the steps of which are as follows:

[0014] S1: thermally depositing polyparaxylene or spin-coating polyimide on a low-resistance silicon wafer to obtain a flexible substrate, vapor-depositing titanium-gold alloy or chromium-gold alloy on the flexible substrate and peeling it off the low-resistance silicon wafer to obtain a flexible upper metal layer electrode; using a mixed solution of polydimethylsiloxane and conductive carbon nanotubes to prepare an elastomeric electrode; forming a multi-scale microstructure on the outer surface of the elastomeric electrode facing the layered composite dielectric, and obtaining a lower metal layer electrode by electron beam or thermal vapor-depositing titanium-gold alloy or chromium-gold alloy on the outer surface of the elastomeric electrode having the multi-scale microstructure, wherein the thickness of the titanium or chromium is 5nm, and the thickness of the gold is 50nm, and finally obtaining an elastomeric composite gate electrode composed of an elastomeric electrode and a metal electrode;

[0015] S2: Thermally deposit polyparaxylene or spin-coat polyimide on a low-resistance silicon wafer to obtain a flexible substrate, and obtain 5nm thick hafnium oxide on the flexible substrate by electron beam evaporation to increase the adhesion between the floating gate and the flexible substrate; evaporate titanium-gold alloy on the surface of the hafnium oxide to obtain an extended floating gate; deposit 10-20nm thick hafnium oxide on the surface of the floating gate by electron beam, and divide the hafnium oxide into two parts by photolithography and dry etching, which serve as the inorganic metal oxide dielectric in the layered composite dielectric layer and the transistor dielectric layer in the carbon nanotube transistor; on the surface of the transistor dielectric layer, deposit a titanium-gold alloy on the surface of the hafnium oxide to obtain an extended floating gate; on the surface of the floating gate, deposit 10-20nm thick hafnium oxide by electron beam, and divide the hafnium oxide into two parts by photolithography and dry etching, which serve as the inorganic metal oxide dielectric in the layered composite dielectric layer and the transistor dielectric layer in the carbon nanotube transistor; on the surface of the transistor dielectric layer, deposit a titanium-gold alloy on the surface of the hafnium oxide to obtain an extended floating gate; on the surface of the floating gate, deposit a titanium-gold alloy on the surface of the floating gate; on the surface of the transistor dielectric layer ... A high-purity semiconductor carbon nanotube film is obtained by pulling and photolithography, that is, a channel is obtained; a source electrode and a drain electrode are obtained at both ends of the channel by electron beam or thermal evaporation; finally, polyparaxylene or polyimide is deposited or spin-coated on the surface of the inorganic metal oxide dielectric, the source electrode, and the drain electrode, wherein the polyparaxylene or polyimide on the inorganic metal oxide dielectric serves as an organic dielectric and forms a layered composite dielectric layer with the inorganic metal oxide dielectric; finally, the silicon wafer at the bottom is peeled off to obtain an integrated layered composite dielectric layer and a carbon nanotube floating gate transistor;

[0016] S3: Laminating the elastomer composite gate electrode obtained in S1, the layered composite dielectric layer obtained in S2, and the carbon nanotube floating gate transistor to obtain a flexible pressure sensor integrated with the carbon nanotube transistor.

[0017] Preferably, the forming of the multi-scale microstructure refers to drop-coating a mixed solution of polydimethylsilane and conductive carbon nanotubes onto a hydrophobic substrate, evacuating the substrate and then heating and curing the mixed solution, and irregular microstructures naturally appear on the surface of the mixed solution during the curing process; or etching a silicon wafer by photolithography to obtain a micro-pyramid structure mold of different sizes, after the mold is hydrophobicized, pouring the mixed solution of polydimethylsilane and conductive carbon nanotubes into the mold and evacuating the substrate, heating and curing the mold, and then peeling off the mold to obtain micro-pyramid structures of different sizes.

[0018] Preferably, the source electrode and the drain electrode in S2 are made of a metal alloy of titanium, palladium and gold by electron beam or thermal evaporation, the thickness of the titanium metal layer is 0.3 nm, the thickness of the palladium metal layer is 40 nm, and the thickness of the gold is 50 nm.

[0019] The beneficial effects of the present invention are as follows:

[0020] The present invention provides a flexible pressure sensor with integrated carbon nanotube transistor, comprising an elastomeric composite gate electrode, a layered composite dielectric layer, and a floating gate carbon nanotube transistor, wherein the elastomeric composite gate electrode is composited by an elastomeric electrode and a metal electrode, the elastomeric electrode is an elastomer prepared from a composite material of polydimethylsiloxane and conductive carbon nanotubes, the elastomeric electrode forms a multi-scale microstructure on the outer surface facing the layered composite dielectric, the metal electrode is a lower metal layer electrode evaporated on the outer surface of the elastomeric electrode with the multi-scale microstructure and an upper metal layer electrode connected to the surface of the elastomeric electrode without the multi-scale microstructure; the layered composite dielectric layer is composed of an organic dielectric and an inorganic metal. The invention relates to a composite structure of an upper and lower layer structure formed by an oxide dielectric, which is located between the outer surface of the elastomer composite gate electrode with a multi-scale microstructure and the floating gate in the floating gate carbon nanotube transistor; the floating gate electrode in the floating gate carbon nanotube transistor is extended in length for integration with the elastomer composite gate electrode and the layered composite dielectric layer, the length of the extended section is greater than the length of the elastomer composite gate electrode and the layered composite dielectric layer, the upper surface of the extended section is connected to the inorganic metal oxide dielectric in the layered composite dielectric layer, and the upper surface of the non-extended section is deposited with the following in order from bottom to top: a transistor dielectric layer, a channel, and a source electrode and a drain electrode located at both ends of the channel, wherein the channel is made of a high-purity semiconductor carbon nanotube film.

[0021] Since the present invention introduces the use of an elastomer composite electrode as a mechanical sensitive element and as a transistor gate at the same time, it avoids the problem of high working voltage and limited sensing performance caused by the weak electrostatic control force of the gate electrode due to the thick thickness of the elastomer dielectric layer and the low relative dielectric constant when using a microstructured dielectric design. The microstructure electrode design adopted in this scheme can select a material with a higher dielectric constant and a thinner dielectric layer as the dielectric layer, that is, a thin film dielectric layer with a mechanical and electrical stability of less than micrometer thickness and a relatively high dielectric constant is obtained by atomic layer deposition, thermal deposition and / or spin coating methods, which can significantly enhance the electrostatic control ability of the gate voltage, and then can realize the conversion of the capacitance change caused by pressure and signal amplification at a lower working voltage, improve the sensing performance of the sensor and reduce the working voltage of the transistor. On the other hand, since the present invention does not adopt the design of a microstructured dielectric, the parameters such as the floating gate area and the relative dielectric constant and thickness of the layered composite dielectric on the floating gate can be adjusted, which increases the flexibility of the integrated sensor design and provides the possibility for high-performance transistor integrated sensors.

[0022] The present invention introduces a carbon nanotube transistor with a floating gate structure, extends the length of the floating gate in the semiconductor carbon nanotube transistor, realizes the integration of the elastomer composite electrode and the carbon nanotube transistor, can directly divide the pressure change through the floating gate and then convert it into a current between the source and the drain, and realizes the conversion of the pressure signal into an easy-to-process electrical signal through an ultra-thin, integrated device structure, and avoids the problem of damage to the semiconductor film caused by directly laminating the microstructure of the mechanical sensitive element on the semiconductor film in the existing design scheme, thereby increasing the mechanical stability of the device; at the same time, compared with the organic semiconductor film, the carbon nanotube semiconductor film has excellent electrical properties and stability, can match the standard photolithography process, and is conducive to the miniaturization and scale of the sensor device. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 : Structural diagram of the flexible pressure sensor with integrated carbon nanotube transistors.

[0024] Figure 2 : Circuit diagram of flexible pressure sensor with integrated carbon nanotube transistors. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the present invention clearer, the flexible pressure sensor integrated with carbon nanotube transistors proposed in the present invention is further described in detail below in combination with the accompanying drawings and specific embodiments. According to the following description, the advantages and features of the present invention will be clearer. It should be noted that the drawings are in a very simplified form and use non-precise proportions, which are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention. In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, please refer to the drawings. It should be noted that the structure, proportion, size, etc. illustrated in the drawings of this specification are only used to match the content disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no technical substantive significance. Any modification of the structure, change in the proportional relationship or adjustment of the size, without affecting the effect that the present invention can produce and the purpose that can be achieved, should still fall within the scope of the technical content disclosed in the present invention.

[0026] The technical solution of the present invention is described in detail below in conjunction with the accompanying drawings. The present invention provides a flexible pressure sensor with integrated carbon nanotube transistors, such as Figure 1 As shown, it includes: an elastomer composite gate electrode 1: a flexible substrate 11, an upper metal layer electrode 12 connected to the surface of the elastomer electrode without a multi-scale microstructure, an elastomer electrode 13 composed of a composite material, a multi-scale microstructure 15 formed on the outer surface of the elastomer electrode facing the layered composite dielectric layer, a lower metal layer electrode 14 evaporated on the surface of the multi-scale microstructure, a layered composite dielectric layer 2: an organic dielectric 21, an inorganic metal oxide dielectric 22, a floating gate carbon nanotube transistor 3: a floating gate 31, a transistor dielectric layer 32, a channel 33, a drain electrode 34, a source electrode 35, a flexible substrate 36, and a hafnium oxide metal layer.

[0027] In some embodiments of the present invention, the elastomeric composite gate electrode 1 is composed of an elastomeric electrode 13 and metal electrodes 12 and 14, wherein the elastomeric electrode 13 is an elastomer made of a composite material of polydimethylsiloxane and conductive carbon nanotubes, and the elastomeric electrode 13 forms a multi-scale microstructure 15 on the outer surface facing the layered composite dielectric layer 2, and the metal electrode is a metal layer 14 evaporated on the outer surface of the elastomeric electrode with a multi-scale microstructure and an upper metal layer electrode 11 connected to the surface of the elastomeric electrode without a multi-scale microstructure; the layered composite dielectric layer 2 is located on the inner surface of the elastomeric composite gate electrode with a multi-scale microstructure 15 and the floating gate electrode in the carbon nanotube crystal 3. 31, an organic dielectric 21 and an inorganic metal oxide dielectric 22 form a composite upper and lower structure; the floating gate 31 in the floating gate carbon nanotube transistor 3 is extended in length for integration with the elastomeric composite gate electrode 1 and the layered composite dielectric layer 2, the length of the extended section is greater than the length of the elastomeric composite gate electrode 1 and the layered composite dielectric layer 2, the upper surface of the extended section is connected to the inorganic metal oxide dielectric 22 in the layered composite dielectric layer 2, and the upper surface of the non-extended section is deposited in sequence from bottom to top: a transistor dielectric layer 32, a channel 33, and a source electrode 35 and a drain electrode 34 located at both ends of the channel, and the channel 33 is made of a high-purity semiconductor carbon nanotube film.

[0028] In some embodiments of the present invention, the preparation method of the polydimethylsiloxane and conductive carbon nanocomposite material for preparing the elastomeric electrode 13 is: mixing polydimethylsiloxane with a n-hexane solution, dispersing the conductive carbon nanotubes in isopropanol by water bath ultrasound, and finally mixing the two solutions; in some embodiments of the present invention, the ratio of polydimethylsiloxane to n-hexane solution is 1:5-1:10, the ratio of conductive carbon nanotubes to isopropanol is 1:200, and the ratio of polydimethylsiloxane to conductive carbon nanotubes is 100:1-100:5.

[0029] In some embodiments of the present invention, the multi-scale microstructure 15 is a plurality of irregular three-dimensional structures; in other embodiments of the present invention, the multi-scale microstructure 5 is a plurality of micro-pyramid structures of different sizes.

[0030] In some embodiments of the present invention, the metal electrodes in the elastomeric composite gate electrode 1: the upper metal layer electrode 12 and the lower metal layer electrode 15 are obtained by electron beam evaporation of titanium-gold alloy, the thickness of titanium is 5nm, and the thickness of gold is 50nm; in other embodiments of the present invention, the metal electrodes in the elastomeric composite gate electrode: the upper metal layer electrode 12 and the lower metal layer electrode 15 are obtained by thermal evaporation of titanium-gold alloy, the thickness of titanium is 5nm, and the thickness of gold is 50nm; in some embodiments of the present invention, the metal electrodes in the elastomeric composite gate electrode 1: the upper metal layer electrode 12 and the lower metal layer electrode 15 are obtained by electron beam evaporation of chromium-gold alloy, the thickness of chromium is 5nm, and the thickness of gold is 50nm; in other embodiments of the present invention, the metal electrodes in the elastomeric composite gate electrode: the upper metal layer electrode 12 and the lower metal layer electrode 15 are obtained by thermal evaporation of chromium-gold alloy, the thickness of chromium is 5nm, and the thickness of gold is 50nm.

[0031] In some embodiments of the present invention, the organic dielectric 21 in the layered composite dielectric layer 2 is polyparaxylene with a thickness of 150 nm, and the inorganic metal oxide dielectric 22 is hafnium oxide with a thickness of 15 nm; in other embodiments of the present invention, the organic dielectric 21 in the layered composite dielectric layer 2 is polyimide with a thickness of 150 nm, and the inorganic metal oxide dielectric 22 is hafnium oxide with a thickness of 15 nm.

[0032] In some embodiments of the present invention, the transistor dielectric layer 32 is made of hafnium oxide and has a thickness of 15 nm.

[0033] In some embodiments of the present invention, a method for preparing a flexible pressure sensor integrated with a carbon nanotube transistor comprises the following steps:

[0034] S1: thermally depositing polyparaxylene or spin-coating polyimide on a low-resistance silicon wafer to obtain a flexible substrate 11, vapor-depositing titanium-gold alloy or chromium-gold alloy on the flexible substrate and peeling it off the low-resistance silicon wafer to obtain an upper metal layer flexible electrode 12; using a mixed solution of polydimethylsiloxane and conductive carbon nanotubes to prepare an elastomer electrode 13; forming a multi-scale microstructure 15 on the outer surface of the elastomer electrode 13 facing the layered composite dielectric 2, and obtaining a metal electrode 14 by electron beam or thermal vapor deposition of titanium-gold alloy or chromium-gold alloy on the outer surface of the elastomer electrode 13 having the multi-scale microstructure 15, wherein the thickness of the titanium or chromium is 5nm, and the thickness of the gold is 50nm, and finally obtaining an elastomer composite gate electrode 1 composed of the elastomer electrode 13 and the metal electrodes 12 and 14;

[0035] S2: thermally depositing polyparaxylene or spin-coating polyimide on a low-resistance silicon wafer to obtain a flexible substrate 36, and obtaining a 5nm thick hafnium oxide 37 on the flexible substrate 36 by electron beam evaporation to increase the adhesion between the floating gate 31 and the flexible substrate 36; then evaporating a titanium-gold alloy on the surface of the hafnium oxide to obtain an extended floating gate 31; electron beam depositing a 10-20nm thick hafnium oxide on the surface of the floating gate 31, and dividing the hafnium oxide into two parts by photolithography and dry etching, which serve as the inorganic metal oxide dielectric 22 in the layered composite dielectric layer 2 and the crystal in the carbon nanotube transistor 3, respectively. A body tube dielectric layer 32; a high-purity semiconductor carbon nanotube film is obtained on the surface of the transistor dielectric layer 32 by pulling and photolithography methods, that is, a channel 33 is obtained; then a source electrode 35 and a drain electrode 34 are obtained at both ends of the channel 33 by electron beam or thermal evaporation methods; finally, polyparaxylene or polyimide is deposited or spin-coated on the surface of the inorganic metal oxide dielectric 22, the source electrode 35, and the drain electrode 34, which together with the inorganic metal oxide dielectric 22 constitute a layered composite dielectric layer 2; finally, the silicon wafer at the bottom is peeled off, that is, an integrated layered composite dielectric layer 2 and a carbon nanotube transistor 3 are obtained;

[0036] S3: The elastomer composite gate electrode 1 obtained in S1 and the layered composite dielectric 2 and the carbon nanotube floating gate transistor 3 obtained in S2 are bonded together to obtain a flexible pressure sensor with integrated carbon nanotube transistors.

[0037] In some embodiments of the present invention, the method for forming the multi-scale microstructure 15 is to drop a mixed solution of polydimethylsiloxane and conductive carbon nanotubes onto a hydrophobic substrate, evacuate the substrate and heat and cure it, and during the curing process of the mixed solution, irregular microstructures naturally appear on the surface; in other embodiments of the present invention, the method for forming the multi-scale microstructure 15 is to etch a silicon wafer by photolithography to obtain micro-pyramid structure molds of different sizes, and after hydrophobic treatment of the mold, pour the mixed solution of polydimethylsiloxane and conductive carbon nanotubes into the mold and evacuate the substrate, heat and cure it, and then peel off the mold to obtain micro-pyramid structures of different sizes.

[0038] In some embodiments of the present invention, the source electrode 35 and the drain electrode 34 are made of titanium, palladium and gold alloy by electron beam or thermal evaporation, the thickness of the titanium metal layer is 0.3nm, the thickness of the palladium metal layer is 40nm, and the thickness of the gold is 50nm.

[0039] Attached Figure 2 The circuit diagram of the flexible pressure sensor with integrated carbon nanotube transistor provided by the present invention. Specifically, according to the circuit diagram, the equivalent gate voltage can be expressed as: In the formula, C s is the capacitance of the mechanical sensitive element; C gis the gate capacitance of the transistor; V gs is the gate voltage. According to the above formula, the change in the equivalent gate voltage can be expressed as: It can be seen from the above formula that the increase in the capacitance change of the mechanical sensitive element, i.e., the elastomer composite gate electrode, can increase the change of the equivalent gate, thereby improving the gate voltage's ability to regulate the source-drain current, that is, this design method allows the sensor to operate at a lower operating voltage.

[0040] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0041] The above-mentioned embodiment only expresses one implementation mode of the present invention, and its description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

Claims

1. A flexible pressure sensor with integrated carbon nanotube transistor, comprising an elastomeric composite gate electrode, a layered composite dielectric layer, and a floating gate carbon nanotube transistor, characterized in that The elastomeric composite gate electrode is composed of an elastomeric electrode and a metal electrode. The elastomeric electrode is an elastomer made of a composite material of polydimethylsiloxane and conductive carbon nanotubes. The elastomeric electrode forms a multi-scale microstructure on the outer surface facing the layered composite dielectric. The metal electrode is a lower metal layer electrode evaporated on the outer surface of the elastomeric electrode with a multi-scale microstructure and an upper metal layer electrode connected to the surface of the elastomeric electrode without a multi-scale microstructure. The layered composite dielectric layer is composed of an organic dielectric and an inorganic metal oxide dielectric to form an upper and lower layer structure. It is located on the elastomeric composite gate electrode. The outer surface with multi-scale microstructure is between the floating gate in the floating gate carbon nanotube transistor; the floating gate electrode in the floating gate carbon nanotube transistor is extended in length for integration with the elastomer composite gate electrode and the layered composite dielectric layer, the length of the extended section is greater than the length of the elastomer composite gate electrode and the layered composite dielectric layer, the upper surface of the extended section is connected to the inorganic metal oxide dielectric in the layered composite dielectric layer, and the upper surface of the non-extended section is deposited in order from bottom to top: a transistor dielectric layer, a channel, and a source electrode and a drain electrode located at both ends of the channel, wherein the channel is made of a high-purity semiconductor carbon nanotube film.

2. The flexible pressure sensor with integrated carbon nanotube transistor according to claim 1, characterized in that The method for preparing the elastomer electrode of the polydimethylsiloxane and conductive carbon nanocomposite material is as follows: polydimethylsiloxane is mixed with a n-hexane solution, conductive carbon nanotubes are dispersed in isopropanol by water bath ultrasound, and finally the two mixed solutions are mixed.

3. The flexible pressure sensor with integrated carbon nanotube transistor according to claim 2, characterized in that The ratio of the polydimethylsiloxane to the n-hexane solution is 1:5-1:10, the ratio of the conductive carbon nanotubes to the isopropanol is 1:200, and the ratio of the polydimethylsiloxane to the conductive carbon nanotubes is 100:1-100:

5.

4. The flexible pressure sensor with integrated carbon nanotube transistor according to claim 1, characterized in that The multi-scale microstructure is a plurality of irregular three-dimensional structures or a plurality of micro-pyramid structures of different sizes.

5. The flexible pressure sensor with integrated carbon nanotube transistor according to claim 1, characterized in that The metal electrode is obtained from titanium-gold alloy or chromium-gold alloy by electron beam or thermal evaporation. The thickness of the titanium or chromium is 5 nm, and the thickness of the gold is 50 nm.

6. The flexible pressure sensor with integrated carbon nanotube transistor according to claim 1, characterized in that: The organic dielectric in the layered composite dielectric layer is polyparaxylene or polyimide, with a thickness of less than 200 nm, and the inorganic metal oxide dielectric is hafnium oxide, with a thickness of 10-20 nm.

7. The flexible pressure sensor with integrated carbon nanotube transistor according to any one of claims 1 to 6, characterized in that: The transistor dielectric layer in the floating gate carbon nanotube transistor is hafnium oxide with a thickness of 10-20 nm.

8. A method for preparing a flexible pressure sensor with integrated carbon nanotube transistor according to any one of claims 1 to 7, comprising the following steps: S1: thermally depositing polyparaxylene or spin-coating polyimide on a low-resistance silicon wafer to obtain a flexible substrate, vapor-depositing titanium-gold alloy or chromium-gold alloy on the flexible substrate and peeling it off the low-resistance silicon wafer to obtain a flexible upper metal layer electrode; using a mixed solution of polydimethylsiloxane and conductive carbon nanotubes to prepare an elastomeric electrode; forming a multi-scale microstructure on the outer surface of the elastomeric electrode facing the layered composite dielectric, and obtaining a lower metal layer electrode by electron beam or thermal vapor-depositing titanium-gold alloy or chromium-gold alloy on the outer surface of the elastomeric electrode having the multi-scale microstructure, wherein the thickness of the titanium or chromium is 5nm, and the thickness of the gold is 50nm, and finally obtaining an elastomeric composite gate electrode composed of an elastomeric electrode and a metal electrode; S2: Thermally deposit polyparaxylene or spin-coat polyimide on a low-resistance silicon wafer to obtain a flexible substrate, and obtain 5nm thick hafnium oxide on the flexible substrate by electron beam evaporation to increase the adhesion between the floating gate and the flexible substrate; evaporate titanium-gold alloy on the surface of the hafnium oxide to obtain an extended floating gate; deposit 10-20nm thick hafnium oxide on the surface of the floating gate by electron beam, and divide the hafnium oxide into two parts by photolithography and dry etching, which serve as the inorganic metal oxide dielectric in the layered composite dielectric layer and the transistor dielectric layer in the carbon nanotube transistor; on the surface of the transistor dielectric layer, deposit a titanium-gold alloy on the surface of the hafnium oxide to obtain an extended floating gate; on the surface of the floating gate, deposit 10-20nm thick hafnium oxide by electron beam, and divide the hafnium oxide into two parts by photolithography and dry etching, which serve as the inorganic metal oxide dielectric in the layered composite dielectric layer and the transistor dielectric layer in the carbon nanotube transistor; on the surface of the transistor dielectric layer, deposit a titanium-gold alloy on the surface of the hafnium oxide to obtain an extended floating gate; on the surface of the floating gate, deposit a titanium-gold alloy on the surface of the floating gate; on the surface of the transistor dielectric layer ... A high-purity semiconductor carbon nanotube film is obtained by pulling and photolithography, that is, a channel is obtained; a source electrode and a drain electrode are obtained at both ends of the channel by electron beam or thermal evaporation; finally, polyparaxylene or polyimide is deposited or spin-coated on the surface of the inorganic metal oxide dielectric, the source electrode, and the drain electrode, wherein the polyparaxylene or polyimide on the inorganic metal oxide dielectric serves as an organic dielectric and forms a layered composite dielectric layer with the inorganic metal oxide dielectric; finally, the silicon wafer at the bottom is peeled off to obtain an integrated layered composite dielectric layer and a carbon nanotube floating gate transistor; S3: Laminating the elastomer composite gate electrode obtained in S1, the layered composite dielectric layer obtained in S2, and the carbon nanotube floating gate transistor to obtain a flexible pressure sensor integrated with the carbon nanotube transistor.

9. The preparation method according to claim 8, characterized in that The forming of the multi-scale microstructure refers to drop-coating a mixed solution of polydimethylsilane and conductive carbon nanotubes onto a hydrophobic substrate, evacuating the substrate and heating and curing the mixed solution, during which irregular microstructures naturally appear on the surface of the mixed solution; or etching a silicon wafer by photolithography to obtain a micro-pyramid structure mold of different sizes, treating the mold hydrophobically, pouring a mixed solution of polydimethylsilane and conductive carbon nanotubes into the mold and evacuating the substrate, heating and curing the mold, and then peeling the mold off to obtain micro-pyramid structures of different sizes.

10. The preparation method according to claim 8 or 9, characterized in that The source electrode and drain electrode in S2 are made of titanium, palladium and gold metal alloys by electron beam or thermal evaporation. The thickness of the titanium metal layer is 0.3nm, the thickness of the palladium metal layer is 40nm, and the thickness of the gold is 50nm.

Images