Bimodal piezoelectric electronics transistor and preparation method thereof

Abstract

The invention discloses a bimodal piezoelectric electronics transistor and a preparation method thereof, and belongs to the technical field of flexible electronic devices. According to the bimodal piezoelectric electronics transistor provided by the invention, a flexible substrate material is used as a bottom electrode, a yttrium-doped zinc oxide functional layer is attached to the bottom electrode, a PMMA barrier layer is prepared on the functional layer, a surface dual electrode is prepared on the PMMA barrier layer, and a packaging outer layer is arranged outside the bottom electrode, the functional layer, the barrier layer and the surface dual electrode. According to the invention, a special planar electrode structure and a rare earth ion doping strategy are combined, the unique static force-dynamic force bimodal signal response capability is realized by representing the semiconductor characteristics and piezoelectricity of Y-DPT, a new idea is provided for multi-modal detection, and the sensor has a wide application prospect in flexible artificial intelligence products.

Description

Technical Field

[0001] The present invention belongs to the technical field of flexible electronic devices, and in particular relates to a dual-mode piezoelectric electronic transistor and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of nanotechnology and the emergence of new materials, a large number of new stress / strain sensors have emerged. This type of sensor can convert mechanical energy into electrical energy and has broad application prospects, especially in the fields of human-computer interaction, medical testing, wearable devices, etc. The development goal of sensors has changed from simply improving performance to expanding detection functions to meet the needs of various detection scenarios. The multimodality of sensors has become a general trend. So far, how to achieve multimodal signal detection in sensors is still a problem to be solved.

[0003] In recent years, researchers have often used special structural designs to combine multi-modal sensors, such as stacking two multifunctional layers together to produce a series of dual-modal sensors such as piezoresistive-piezoelectric, piezoresistive-triboelectric, and piezoelectric-triboelectric. However, this composite material also faces many problems such as signal interference, difficulty in decoupling, and high manufacturing cost.

[0004] In the existing technology, researchers have focused on improving its sensitivity, such as doping or surface modification of materials to reduce carrier screening effects, and exploring materials with special functions or high performance. Few studies have focused on its unique dual-mode signal response capability. Although improving sensitivity is important, previous studies have been limited to theory and have no practical applications. How to make these two characteristics compatible and integrate their advantages is the key to applying piezoelectric sensors to practical applications. Therefore, it is urgent to find a new solution to realize piezoelectric transistors with dual-mode signal response. Summary of the invention

[0005] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a dual-mode piezoelectric electronic transistor and a method for preparing the same, so as to solve the problems of signal interference, decoupling difficulties and low accuracy caused by the use of material stacking in the prior art to achieve multi-modal signal detection of a single device.

[0006] The technical solution of the present invention to solve the above technical problems is as follows: a dual-mode piezoelectric electronic transistor is provided, wherein a flexible substrate material is used as a bottom electrode, a functional layer of yttrium-doped zinc oxide is attached to the bottom electrode, a PMMA barrier layer is prepared on the functional layer, a surface double electrode is prepared on the PMMA barrier layer, and an encapsulation outer layer is arranged outside the bottom electrode, the functional layer, the PMMA barrier layer and the surface double electrode.

[0007] The beneficial effects of the present invention are as follows: the present invention dopes yttrium ions into zinc oxide, causing severe lattice distortion and symmetry breaking, significantly enhancing the piezoelectric output of zinc oxide with a hexagonal wurtzite structure, generating a large amount of piezoelectric polarization charge, and relying on a special interface effect, ultimately affecting the carrier transport at the metal-semiconductor interface, and exhibiting good dual-modal force response capability when an external bias is applied. The barrier layer transforms the metal-semiconductor interface into a metal-insulator-semiconductor interface, and utilizes the carrier transition mechanism to effectively increase the sensitivity of the device, while ensuring that the device will not short-circuit. The surface dual-electrode structure makes it easier for the external current to cross the potential barrier when a force load is applied, ensuring that the device has a higher sensitivity under the same force load, further improving its sensing performance.

[0008] On the basis of the above technical solution, the present invention can also be improved as follows:

[0009] Furthermore, the flexible substrate material is a flexible PEN-ITO conductive film, which is prepared by coating ITO on a PEN film, and the thickness of the coated ITO is 185 nm.

[0010] The beneficial effects of adopting the above further technical solution are: using the flexible PEN-ITO substrate as the bottom electrode material of the piezoelectric electronic transistor, while ensuring its low square resistance, making the device flexible, reducing the process requirements, and solving the limitations of traditional zinc oxide rigid devices.

[0011] Furthermore, the thickness of the PMMA barrier layer is 50 nm.

[0012] Furthermore, the functional layer includes a zinc oxide seed layer and a zinc oxide nanorod array attached to the zinc oxide seed layer. The zinc oxide nanorods in the zinc oxide nanorod array have a length of 1 to 2 μm and a diameter of 100 to 500 nm.

[0013] Furthermore, the surface double electrodes are parallel double electrodes, and the material is silver.

[0014] Furthermore, the thickness of the metal electrode is 40 to 100 nm.

[0015] Furthermore, the material of the outer packaging layer is polyurethane.

[0016] The beneficial effect of adopting the above further technical solution is: using the PU polyurethane encapsulation outer layer can maintain the stability of the device and withstand a large amount of external loads such as bending and torsion without destroying the device structure.

[0017] The present invention also provides a method for preparing the above-mentioned dual-mode piezoelectric electronic transistor, comprising the following steps:

[0018] S1: Use the flexible substrate material as the bottom electrode, and ultrasonically clean it with acetone, ethylene glycol and alcohol respectively, each cleaning time is 5 to 10 minutes, then rinse it with deionized water, and then ultrasonically clean it twice with deionized water, each cleaning time is 5 to 10 minutes, blow dry it with nitrogen, and then ultrasonically clean it with acetone and ethanol twice, each cleaning time is 5 to 10 minutes, blow dry it with nitrogen, and set it aside;

[0019] S2: Prepare a zinc oxide seed layer on a flexible substrate material by magnetron sputtering, with a radio frequency power of 60 to 80 W and a sputtering time of 1 to 2 h;

[0020] S3: Zn(NO3)2·6H2O, C6H 12 N4 and Y(NO3)3·6H2O are dissolved in water to obtain a precursor solution containing yttrium oxide and zinc oxide; the concentration of yttrium oxide in the precursor solution is 0.01-0.02M, and the concentration of zinc oxide is 0.1-0.2M;

[0021] S4: placing the flexible substrate material with the zinc oxide seed layer obtained in step S2 in the precursor solution prepared in step S3 and heating it at a temperature of 80 to 100° C. for a heating time of 3 to 6 hours to generate a zinc oxide nanorod array and form a functional layer of yttrium-doped zinc oxide on the surface of the flexible substrate material;

[0022] S5: dissolving PMMA in a mixed solution of acetone and N,N-dimethylacetamide to obtain a solution with a PMMA mass fraction of 10wt% to 15wt%, and spin-coating the obtained solution onto the functional layer to form a PMMA barrier layer on the surface of the functional layer; the spin-coating process is firstly spin-coating at a speed of 500 to 1000 rpm for 10 to 15 seconds, then spin-coating at 3000 to 4000 rpm for 30 to 60 seconds, and drying;

[0023] S6: The surface double electrodes are deposited on the PMMA barrier layer by magnetron sputtering, the RF power is 40-50W, the sputtering time is 10-15min, the electrodes are clamped with silver glue and connected to the copper wire, and the external electrodes are led out by wires;

[0024] S7: Encapsulate the above device to form an outer packaging layer on the surface.

[0025] The beneficial effects of adopting the above technical solution are: using magnetron sputtering to first prepare a zinc oxide seed layer on a flexible base material, providing nucleation sites for the subsequent growth of zinc oxide nanorods, while reducing the lattice mismatch between the zinc oxide nanorods and the base material, so that the zinc oxide and the base material are in close contact, which is conducive to the vertical growth of the zinc oxide nanorods.

[0026] With Zn(NO3)2·6H2O, Y(NO3)3·6H2O and C6H 12N4 is used as the raw material for preparing the precursor solution, and Zn(NO3)2·6H2O provides the zinc ions (Zn 2+ ), while C6H 12 N4 adjusts the pH value of the precursor solution to ensure that the hydroxide ions (OH) required for the growth of ZnO nanorods can be slowly released in the solution. - ); C6H 12 OH released slowly by N4 hydrolysis - Zn(NO3)2·6H2O 2+ and Y(NO3)3·6H2O 3+ The reaction generates Zn(OH)2 deposition and Y(OH)3 deposition, which decompose into ZnO and Y2O3 under high temperature conditions, and finally form Y-doped zinc oxide nanorod arrays. The introduction of rare earth elements (yttrium) can cause the symmetry of the original crystal structure of ZnO to break, which helps to enhance piezoelectric polarization; on the other hand, the unique surface electronic state of rare earth elements is used to sharpen the energy band, reduce the metal-semiconductor interface barrier, optimize the effective mass of carriers, increase carrier mobility, and improve semiconductor properties.

[0027] On the basis of the above technical solution, the present invention can also be improved as follows:

[0028] Furthermore, the concentration of yttrium oxide in the precursor solution is 0.01M, and the concentration of zinc oxide is 0.1M.

[0029] Furthermore, the target material for magnetron sputtering in step S6 is metallic silver.

[0030] The present invention has the following beneficial effects:

[0031] 1. The present invention successfully prepared a device capable of detecting dual-mode force in a single material through innovations in material modification, manufacturing process and device structure, solving the limitation that previous devices could only rely on composite materials and multi-functional layer stacking. Combined with a special planar electrode structure and rare earth (Y) ion doping strategy, dual-mode response of static and dynamic forces is achieved, while improving the sensitivity of the device.

[0032] 2. The piezoelectric electronic transistor provided by the present invention can be applied to wearable strain sensors. Due to the coupling of piezoelectric and semiconductor carrier transport characteristics, the transistor uses strain-induced charges and the corresponding piezoelectric potential at the interface to linearly adjust the interface barrier height and exponentially control the carrier transport at the piezoelectric semiconductor interface, thereby directly converting mechanical signals into electrical control. At the same time, due to its unique interface effect, when static force is applied to the sample surface, due to the influence of induced polarization charge, the external current is more likely to pass through the metal semiconductor interface, and maintain this interface change after the external force is removed, so that static and dynamic force dual modal response can be achieved.

[0033] 3. The present invention realizes a dual-mode piezoelectric transistor based on Y-ion doped ZnO (Y-DPT). By characterizing the semiconductor properties and piezoelectricity of Y-DPT, its unique dual-modal signal response capability is realized, providing a new idea for multimodal detection, and has broad application prospects in flexible artificial intelligence products. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the structure of the dual-mode piezoelectric electronic transistor of the present invention;

[0035] Figure 2 It is a schematic diagram of the structure of the dual-mode piezoelectric electronic transistor of the present invention;

[0036] Figure 3 is a top view SEM image of the functional layer of the transistor of Example 1;

[0037] Figure 4 is a cross-sectional SEM image of the functional layer of the transistor of Example 1;

[0038] Figure 5 HRTEM images of transistor functional layers of Example 1 and Comparative Example 1, wherein the left image is Comparative Example 1 and the right image is Example 1;

[0039] Figure 6 KPFM diagrams of transistor functional layers of Example 1 and Comparative Example 1, wherein the left diagram is Comparative Example 1 and the right diagram is Example 1;

[0040] Figure 7 is the PFM surface potential diagram of the transistor of Comparative Example 1;

[0041] Figure 8 is the PFM surface potential diagram of Example 1;

[0042] Fig. 9 It is a comparison diagram of static force detection of transistors prepared in Comparative Example 2 and Example 1, wherein the upper diagram is Comparative Example 2 and the lower diagram is Example 1;

[0043] Fig.10 The data diagram of the response of the transistor of Example 1 to the static force and the dynamic force, wherein the upper diagram is the static force and the lower diagram is the dynamic force;

[0044] Fig.11 is a sensitivity diagram of the transistor of Example 1;

[0045] In the figure, 1, bottom electrode; 2, functional layer; 21, zinc oxide seed layer; 22, zinc oxide nanorod array; 3, PMMA barrier layer; 4, surface double electrode; 5, encapsulation outer layer. DETAILED DESCRIPTION

[0046] The flexible PEN-ITO conductive film used in the embodiment of the present invention is purchased from Shenzhen South China Xiangcheng Technology Co., Ltd. The flexible PEN-ITO conductive film is prepared by coating indium tin oxide (ITO) on polyethylene terephthalate (PEN, polyester film). The thickness of the flexible PEN-ITO conductive film is 125 μm, and the thickness of the ITO layer is 185 nm. If the specific conditions are not specified in the embodiment, the conventional conditions or the conditions recommended by the manufacturer are followed. The reagents or instruments used without indicating the manufacturer are all conventional products that can be purchased commercially. The principles and features of the present invention are described below in conjunction with the embodiments. The examples cited are only used to explain the present invention and are not used to limit the scope of the present invention.

[0047] Embodiment 1:

[0048] like Figure 1 and Figure 2 As shown, this embodiment provides a dual-mode piezoelectric electronic transistor, with a flexible PEN-ITO conductive film as a bottom electrode 1, a functional layer 2 of yttrium-doped zinc oxide attached to the bottom electrode, a PMMA barrier layer 3 is arranged on the functional layer, a surface double electrode 4 is arranged on the PMMA barrier layer 3, and an encapsulation outer layer 5 is arranged outside the bottom electrode 1, the functional layer 2, the PMMA barrier layer 3 and the surface double electrode 4.

[0049] This embodiment also provides a method for preparing the above-mentioned dual-mode piezoelectric electronic transistor, comprising the following steps:

[0050] S1: Use a flexible PEN-ITO conductive film (20 mm×20 mm) as the bottom electrode 1, and ultrasonically clean it with acetone, ethylene glycol and alcohol respectively, each cleaning time is 5 minutes, then rinse with deionized water, and then put it into a beaker filled with deionized water for ultrasonic cleaning for 5 minutes; then put it into another beaker filled with deionized water for ultrasonic cleaning for 5 minutes, then take it out, and immediately blow it dry with a nitrogen gun; then put it into acetone for ultrasonic cleaning for 5 minutes, then take it out, and immediately put it into a beaker filled with ethanol, ultrasonically clean it for 5 minutes, then take it out, and immediately blow it dry with a nitrogen gun for standby use;

[0051] S2: Using magnetron sputtering, a zinc oxide seed layer 21 is prepared on the flexible PEN-ITO conductive film, the flow rate of nitrogen and oxygen is 40:1, the RF power is 60W, and the sputtering time is 2h;

[0052] S3: Add zinc nitrate hexahydrate (Zn(NO3)2·6H2O), hexamethylenetetramine (C6H 12 N4) and Y(NO3)3·6H2O are dissolved in water and stirred to obtain a precursor solution containing zinc oxide and yttrium oxide, wherein the concentration of yttrium oxide in the precursor solution is 0.01M and the concentration of zinc oxide is 0.1M;

[0053] S4: placing the PEN-ITO conductive film with the zinc oxide seed layer 21 obtained in step S2 in the precursor solution prepared in step S3, heating in an oven at a temperature of 85° C. for 6 hours, generating a zinc oxide nanorod array 22, and forming a yttrium-doped zinc oxide functional layer 2 on the surface of the PEN-ITO conductive film; the zinc oxide nanorods have a length of 1 to 2 μm and a diameter of 200 to 500 nm;

[0054] S5: PMMA solid particles are dissolved in a mixed solution of acetone and N,N-dimethylacetamide (the mass ratio of acetone to N,N-dimethylacetamide is 1:1) to obtain a solution with a PMMA mass fraction of 10 wt%, and the obtained solution is spin-coated onto the zinc oxide nanorod array 22 of the functional layer. The spin coating process is firstly spin-coated at a speed of 500 rpm for 15 s, then spin-coated at 3500 rpm for 45 s, and then baked at 80°C for 1 h to form a PMMA barrier layer 3 on the surface of the functional layer. ， The thickness of the PMMA barrier layer 3 is 50 nm;

[0055] S6: Deposit the metallic silver target solution on the PMMA barrier layer 3 by magnetron sputtering to obtain parallel source / drain Ag electrodes 4 (4 mm×5 mm), with a sputtering power of 40 W, a time of 10 min, and an electrode thickness of 50 nm. Clamp the electrodes with silver glue and connect them to the copper wire, and lead out the external electrodes with wires;

[0056] S7: Encapsulate the above device with a commercial PU film to form an encapsulation outer layer 5 on the surface.

[0057] Embodiment 2:

[0058] like Figure 1 and Figure 2 As shown, this embodiment provides a dual-mode piezoelectric electronic transistor, with a flexible PEN-ITO conductive film as a bottom electrode 1, a functional layer 2 of yttrium-doped zinc oxide attached to the bottom electrode, a PMMA barrier layer 3 is arranged on the functional layer 2, a surface double electrode 4 is arranged on the PMMA barrier layer 3, and an encapsulation outer layer 5 is arranged outside the bottom electrode 1, the functional layer 2, the PMMA barrier layer 3 and the surface double electrode 4.

[0059] This embodiment also provides a method for preparing the above-mentioned dual-mode piezoelectric electronic transistor, comprising the following steps:

[0060] S1: Use the flexible PEN-ITO conductive film (20 mm×20 mm) as the bottom electrode 1, and ultrasonically clean it with acetone, ethylene glycol and alcohol respectively, each cleaning time is 10 minutes, then rinse it with deionized water, and then put it into a beaker filled with deionized water for ultrasonic cleaning for 10 minutes; then put it into another beaker filled with deionized water for ultrasonic cleaning for 10 minutes, then take it out, and immediately blow it dry with a nitrogen gun; then put it into acetone for ultrasonic cleaning for 10 minutes, then take it out, and immediately put it into a beaker filled with ethanol, and then take it out after ultrasonic cleaning for 10 minutes, and immediately blow it dry with a nitrogen gun for standby use;

[0061] S2: Using magnetron sputtering, a zinc oxide seed layer 21 is prepared on the flexible PEN-ITO conductive film, the flow rate of nitrogen and oxygen is 40:1, the RF power is 80W, and the sputtering time is 1h;

[0062] S3: Add zinc nitrate hexahydrate (Zn(NO3)2·6H2O), hexamethylenetetramine (C6H 12 N4) and Y(NO3)3·6H2O are dissolved in water and stirred to obtain a precursor solution containing zinc oxide and yttrium oxide, wherein the concentration of yttrium oxide in the precursor solution is 0.02M and the concentration of zinc oxide is 0.2M;

[0063] S4: placing the PEN-ITO conductive film with the zinc oxide seed layer 21 obtained in step S2 in the precursor solution prepared in step S3, heating in an oven at a temperature of 95° C. for 4 hours, generating a zinc oxide nanorod array 22, and forming a yttrium-doped zinc oxide functional layer 2 on the surface of the PEN-ITO conductive film; the zinc oxide nanorods have a length of 1 to 2 μm and a diameter of 200 to 500 nm;

[0064] S5: PMMA solid particles are dissolved in a mixed solution of acetone and N,N-dimethylacetamide (the mass ratio of acetone to N,N-dimethylacetamide is 1:1) to obtain a solution with a PMMA mass fraction of 15wt%, and the obtained solution is spin-coated onto the zinc oxide nanorod array 22 of the functional layer. The spin coating process is firstly spin-coated at a speed of 1000 rpm for 10 seconds, then spin-coated at 4000 rpm for 30 seconds, and then baked at 80°C for 1 hour to form a PMMA barrier layer 3 on the surface of the functional layer. ， The thickness of the PMMA barrier layer 3 is 50 nm;

[0065] S6: Deposit the metallic silver target solution on the PMMA barrier layer 3 by magnetron sputtering to obtain parallel source / drain Ag electrodes 4 (4 mm×5 mm), with a sputtering power of 50 W, a time of 15 min, and an electrode thickness of 80 nm. Clamp the electrodes with silver glue and connect them to the copper wire, and lead out the external electrodes with wires;

[0066] S7: Encapsulate the above device with a commercial PU film to form an encapsulation outer layer 5 on the surface.

[0067] Embodiment 3:

[0068] like Figure 1 and Figure 2 As shown, this embodiment provides a dual-mode piezoelectric electronic transistor, with a flexible PEN-ITO conductive film as a bottom electrode 1, a functional layer 2 of yttrium-doped zinc oxide attached to the bottom electrode, a PMMA barrier layer 3 is arranged on the functional layer 2, a surface double electrode 4 is arranged on the PMMA barrier layer 3, and an encapsulation outer layer 5 is arranged outside the bottom electrode 1, the functional layer 2, the PMMA barrier layer 3 and the surface double electrode 4.

[0069] This embodiment also provides a method for preparing the above-mentioned dual-mode piezoelectric electronic transistor, comprising the following steps:

[0070] S1: A flexible PEN-ITO conductive film (20 mm × 20 mm) was used as the bottom electrode 1, and ultrasonically cleaned with acetone, ethylene glycol and alcohol respectively, each cleaning time was 8 min, and then rinsed with deionized water, and then placed in a beaker filled with deionized water for ultrasonic treatment for 8 min; then placed in another beaker filled with deionized water for ultrasonic treatment for 8 min, then taken out, and immediately dried with a nitrogen gun; then placed in acetone for ultrasonic treatment for 8 min, then taken out, and immediately placed in a beaker filled with ethanol, and then taken out for ultrasonic treatment for 8 min, then immediately dried with a nitrogen gun, and set aside;

[0071] S2: Using magnetron sputtering, a zinc oxide seed layer 21 is prepared on the flexible PEN-ITO conductive film, the flow rate of nitrogen and oxygen is 40:1, the RF power is 70W, and the sputtering time is 1.5h;

[0072] S3: Add zinc nitrate hexahydrate (Zn(NO3)2·6H2O), hexamethylenetetramine (C6H 12 N4) and Y(NO3)3·6H2O are dissolved in water and stirred to obtain a precursor solution containing zinc oxide and yttrium oxide, wherein the concentration of yttrium oxide in the precursor solution is 0.015M and the concentration of zinc oxide is 0.15M;

[0073] S4: placing the PEN-ITO conductive film with the zinc oxide seed layer 21 obtained in step S2 in the precursor solution prepared in step S3, and heating in an oven at a heating temperature of 90° C. for a heating time of 5 hours to generate a zinc oxide nanorod array 22, and forming a yttrium-doped zinc oxide functional layer 2 on the surface of the PEN-ITO conductive film; the zinc oxide nanorods have a length of 1 to 2 μm and a diameter of 200 to 500 nm;

[0074] S5: PMMA solid particles are dissolved in a mixed solution of acetone and N,N-dimethylacetamide (the mass ratio of acetone to N,N-dimethylacetamide is 1:1) to obtain a solution with a PMMA mass fraction of 12 wt%, and the obtained solution is spin-coated onto the zinc oxide nanorod array 22 of the functional layer. The spin coating process is firstly spin-coated at a speed of 800 rpm for 12 s, then spin-coated at 3000 rpm for 60 s, and then baked at 80°C for 1 h to form a PMMA barrier layer 3 on the surface of the functional layer. ， The thickness of the PMMA barrier layer 3 is 50 nm;

[0075] S6: Deposit the metallic silver target solution on the PMMA barrier layer 3 by magnetron sputtering to obtain parallel source / drain Ag electrodes 4 (4 mm×5 mm), with a sputtering power of 45 W, a time of 12 min, and an electrode thickness of 60 nm. Clamp the electrodes with silver glue and connect them to the copper wire, and lead out the external electrodes with wires;

[0076] S7: Encapsulate the above device with a commercial PU film to form an encapsulation outer layer 5 on the surface.

[0077] Comparative Example 1:

[0078] This comparative example provides a dual-mode piezoelectric electronic transistor, with a flexible PEN-ITO conductive film as a bottom electrode, a zinc oxide functional layer attached to the bottom electrode, a PMMA barrier layer arranged on the functional layer, a surface double electrode arranged on the PMMA barrier layer 3, and an encapsulation outer layer arranged outside the bottom electrode, the functional layer, the PMMA barrier layer and the surface double electrode.

[0079] This comparative example also provides a method for preparing the above-mentioned dual-mode piezoelectric electronic transistor, comprising the following steps:

[0080] S1: Use the flexible PEN-ITO conductive film (20mm×20mm) as the bottom electrode, and ultrasonically clean it with acetone, ethylene glycol and alcohol respectively, each cleaning time is 5 minutes, then rinse with deionized water, and then put it into a beaker filled with deionized water for ultrasonic cleaning for 5 minutes; then put it into another beaker filled with deionized water for ultrasonic cleaning for 5 minutes, then take it out and immediately blow it dry with a nitrogen gun; then put it into acetone for ultrasonic cleaning for 5 minutes, then take it out, and immediately put it into a beaker filled with ethanol, and then take it out after ultrasonic cleaning for 5 minutes, and immediately blow it dry with a nitrogen gun for standby use;

[0081] S2: Using magnetron sputtering, a zinc oxide seed layer was prepared on the flexible PEN-ITO conductive film. The flow rate of nitrogen and oxygen was 40:1, the RF power was 60W, and the sputtering time was 2h.

[0082] S3: Add zinc nitrate hexahydrate (Zn(NO3)2·6H2O), hexamethylenetetramine (C6H 12N4), dissolved in water and stirred to obtain a precursor solution containing zinc oxide, wherein the concentration of zinc oxide is 0.1 M;

[0083] S4: placing the PEN-ITO conductive film with the zinc oxide seed layer obtained in step S2 in the precursor solution prepared in step S3, heating in an oven at a temperature of 85° C. for 6 hours, generating a zinc oxide nanorod array, and forming a zinc oxide functional layer on the surface of the PEN-ITO conductive film; the zinc oxide nanorods have a length of 1 to 2 μm and a diameter of 200 to 500 nm;

[0084] S5: PMMA solid particles are dissolved in a mixed solution of acetone and N,N-dimethylacetamide (the mass ratio of acetone to N,N-dimethylacetamide is 1:1) to obtain a solution with a PMMA mass fraction of 10wt%, and the obtained solution is spin-coated onto the zinc oxide nanorod array of the functional layer. The spin coating process is firstly spin-coated at a speed of 500rpm for 15s, then spin-coated at 3500rpm for 45s, and then baked at 80°C for 1h to form a PMMA barrier layer on the surface of the functional layer. The thickness of the PMMA barrier layer is 50nm;

[0085] S6: The metallic silver target solution was deposited on the PMMA barrier layer by magnetron sputtering to obtain parallel source / drain Ag electrodes (4 mm × 5 mm), with a sputtering power of 40 W for 10 min and an electrode thickness of 60 nm. The electrodes were clamped with silver glue and connected to the copper wire, and the external electrodes were led out with wires;

[0086] S7: Encapsulate the above device with a commercial PU film to form an encapsulation outer layer on the surface.

[0087] Comparative Example 2:

[0088] This comparative example provides a traditional zinc oxide piezoelectric device, with a flexible PEN-ITO conductive film as a bottom electrode, a zinc oxide functional layer, a PMMA barrier layer and a top electrode attached to the bottom electrode, and an encapsulation outer layer is arranged outside the bottom electrode, the functional layer, the barrier layer and the top electrode.

[0089] This comparative example also provides a method for preparing the above-mentioned traditional zinc oxide piezoelectric device, comprising the following steps:

[0090] S1: Use the flexible PEN-ITO conductive film (20mm×20mm) as the bottom electrode, and ultrasonically clean it with acetone, ethylene glycol and alcohol respectively, each cleaning time is 8 minutes, then rinse with deionized water, and then put it into a beaker filled with deionized water for ultrasonic cleaning for 8 minutes; then put it into another beaker filled with deionized water for ultrasonic cleaning for 8 minutes, take it out, and immediately blow it dry with a nitrogen gun; then put it into acetone for ultrasonic cleaning for 8 minutes, take it out, and immediately put it into a beaker filled with ethanol, take it out after ultrasonic cleaning for 8 minutes, and immediately blow it dry with a nitrogen gun for use;

[0091] S2: Using magnetron sputtering, a zinc oxide seed layer was prepared on the flexible PEN-ITO conductive film. The flow rate of nitrogen and oxygen was 40:1, the RF power was 50W, and the sputtering time was 0.5h.

[0092] S3: Add zinc nitrate hexahydrate (Zn(NO3)2·6H2O), hexamethylenetetramine (C6H 12 N4), dissolved in water and stirred to obtain a precursor solution containing zinc oxide, wherein the concentration of zinc oxide is 0.15M;

[0093] S4: placing the PEN-ITO conductive film with the zinc oxide seed layer obtained in step S2 in the precursor solution prepared in step S3, heating in an oven at a temperature of 80° C. for 3 hours to generate a zinc oxide nanorod array, and forming a zinc oxide functional layer on the surface of the PEN-ITO conductive film; the zinc oxide nanorods have a length of 1 to 2 μm and a diameter of 200 to 500 nm;

[0094] S5: PMMA solid particles are dissolved in a mixed solution of acetone and N,N-dimethylacetamide (the mass ratio of acetone to N,N-dimethylacetamide is 1:1) to obtain a solution with a PMMA mass fraction of 15wt%, and the obtained solution is spin-coated onto the zinc oxide nanorod array of the functional layer. The spin coating process is firstly spin-coated at a speed of 300rpm for 10s, then spin-coated at 3000rpm for 60s, and then baked at 80°C for 1h to form a PMMA barrier layer on the surface of the functional layer. The thickness of the PMMA barrier layer is 60nm;

[0095] S6: The metallic silver target solution was deposited on the PMMA barrier layer by magnetron sputtering to obtain a single-electrode Ag electrode (4 mm × 5 mm), with a sputtering power of 45 W, a time of 12 min, and an electrode thickness of 60 nm. The electrode was clamped with silver glue and connected to the copper wire, and the external electrode was led out with a wire;

[0096] S7: Encapsulate the above device with a commercial PU film to form an encapsulation outer layer on the surface.

[0097] Experimental example:

[0098] The performances of the transistors prepared in Examples 1-3 of the present invention are similar, and Example 1 and Comparative Examples 1 and 2 are selected for experimental analysis and testing.

[0099] The functional layers of the transistors prepared in Example 1 and Comparative Example 1 were observed by SEM using a JSM-7800F, Japan Electronics Co., Ltd electron microscope. Figure 3 and Figure 4The second is the SEM images of the cross section and top of the functional layer. The microscopic morphology of the zinc oxide nanorod array can be clearly observed from the images. The diameter of the zinc oxide nanorods is 200-500nm and the length is 1-2μm.

[0100] Figure 5 This is the result of HRTEM observation of the transistor functional layer prepared in Example 1 and Comparative Example 1 using a FEI, USA transmission electron microscope. It can be seen from the figure that the crystal plane spacing changes before (left) and after (right) yttrium doping, proving that doping causes lattice distortion. Lattice distortion greatly enhances piezoelectricity by attracting a large number of free carriers and reducing the piezoelectric shielding effect, thereby reducing the difficulty of external loads passing through the interface barrier, thereby improving the sensitivity of the device.

[0101] Figure 6 These are the KPFM images of Example 1 and Comparative Example 1 before (left) and after (right) yttrium-doped zinc oxide. It can be seen from the figures that the work function is improved after yttrium doping. The improvement of the work function also proves that doping can reduce the carrier concentration and improve the piezoelectric output, thereby enhancing the interface effect and improving the response of the device.

[0102] Figure 7 and Figure 8 The data result diagram is obtained by observing the surface piezoelectric response of the transistors prepared in Example 1 and Comparative Example 1. It can be seen from the figure that compared with the surface piezoelectric response of the transistors prepared in Example 1 and Comparative Example 1, the surface piezoelectric response of the transistors prepared in Example 1 and Comparative Example 1 is better than that of the transistors prepared in Example 1 and Comparative Example 1. Figure 7 ), after yttrium doped zinc oxide ( Figure 8 ), the surface potential is increased, and the increase in surface potential helps the external current to cross the interface barrier.

[0103] Fig. 9 The result diagram is obtained by comparing the force response curves of the conventional device provided in comparative example 2 (upper figure) and the transistor provided in embodiment 1 of the present invention (lower figure) using a linear motor and a 6514 test system. It can be seen from the figure that the transistor provided by the present invention has a static force response capability, while the conventional device cannot do this;

[0104] Fig.10 This is a result graph obtained by testing the static force (upper figure) output and dynamic force (lower figure) output of the transistor provided in Example 1 of the present invention using a linear motor and a 6514 test system. It can be seen from the figure that the device can respond well to static force and dynamic force, there is no obvious attenuation in 5 cycles, and the signal can be well consistent with the external force.

[0105] Fig.11 This is an IV curve result diagram obtained by measuring the transistor of Example 1 using a 4200 semiconductor test system. It can be seen from the diagram that the sensitivity performance of the device is relatively good under different forces and switching ratios under different bias voltages.

[0106] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A dual-mode piezoelectric electronic transistor, characterized in that: A flexible substrate material is used as a bottom electrode (1), a functional layer (2) of yttrium-doped zinc oxide is attached to the bottom electrode (1), a PMMA barrier layer (3) is prepared on the functional layer, a surface double electrode (4) is prepared on the PMMA barrier layer (3), and an encapsulation outer layer (5) is arranged outside the bottom electrode (1), the functional layer (2), the PMMA barrier layer (3) and the surface double electrode (4).

2. The bimodal piezoelectric electronic transistor according to claim 1, characterized in that: The flexible substrate material is a flexible PEN-ITO conductive film, which is prepared by coating ITO on a PEN film, and the thickness of the coated ITO is 185 nm.

3. The bimodal piezoelectric electronic transistor according to claim 2, characterized in that: The thickness of the PMMA barrier layer (3) is 50 nm.

4. The bimodal piezoelectric electronic transistor according to claim 1, characterized in that: The functional layer (2) comprises a zinc oxide seed layer (21) and a zinc oxide nanorod array (22) attached to the zinc oxide seed layer (21); the zinc oxide nanorods in the zinc oxide nanorod array (22) have a length of 1 to 2 μm and a diameter of 100 to 500 nm.

5. The bimodal piezoelectric electronic transistor according to claim 1, characterized in that: The surface double electrodes (4) are parallel double electrodes, and the material is silver.

6. The bimodal piezoelectric electronic transistor according to claim 5, characterized in that: The thickness of the metal electrode is 40-100 nm.

7. The bimodal piezoelectric electronic transistor according to claim 1, characterized in that: The material of the packaging outer layer (5) is polyurethane.

8. The method for preparing the dual-mode piezoelectric electronic transistor according to any one of claims 1 to 7, characterized in that: The following steps are involved: S1: The flexible substrate material is used as the bottom electrode (1), and ultrasonically cleaned with acetone, ethylene glycol and alcohol respectively, each cleaning time is 5 to 10 minutes, then rinsed with deionized water, ultrasonically cleaned twice with deionized water, each cleaning time is 5 to 10 minutes, blown dry with nitrogen, and then ultrasonically cleaned twice with acetone and ethanol respectively, each cleaning time is 5 to 10 minutes, blown dry with nitrogen, and set aside; S2: preparing a zinc oxide seed layer (21) on a flexible substrate material by magnetron sputtering, with a radio frequency power of 60 to 80 W and a sputtering time of 1 to 2 h; S3: Zn(NO3)2·6H2O, C6H 12 N4 and Y(NO3)3·6H2O are dissolved in water to obtain a precursor solution containing yttrium oxide and zinc oxide; the concentration of yttrium oxide in the precursor solution is 0.01-0.02M, and the concentration of zinc oxide is 0.1-0.2M; S4: placing the flexible substrate material with the zinc oxide seed layer (21) obtained in step S2 in the precursor solution prepared in step S3 and heating it at a temperature of 80 to 100° C. for a heating time of 3 to 6 hours to generate a zinc oxide nanorod array (22) and form a yttrium-doped zinc oxide functional layer (2) on the surface of the flexible substrate material; S5: dissolving PMMA in a mixed solution of acetone and N,N-dimethylacetamide to obtain a solution with a PMMA mass fraction of 10 wt% to 15 wt%, and spin-coating the obtained solution onto the functional layer (2) to form a PMMA barrier layer (3) on the surface of the functional layer (2); the spin-coating process is firstly spin-coating at a speed of 500 to 1000 rpm for 10 to 15 seconds, then spin-coating at a speed of 3000 to 4000 rpm for 30 to 60 seconds, and drying; S6: depositing a surface double electrode (4) on the PMMA barrier layer (3) by magnetron sputtering, the radio frequency power is 40-50W, the sputtering time is 10-15min, the electrode is clamped with silver glue and connected to the copper wire, and the external electrode is led out by a wire; S7: Encapsulate the above device to form an encapsulation outer layer (5) on the surface.

9. The preparation method according to claim 8, characterized in that: The concentration of yttrium oxide in the precursor solution is 0.01M, and the concentration of zinc oxide is 0.1M.

10. The preparation method according to claim 8, characterized in that: The target material for magnetron sputtering in step S6 is metallic silver.

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