A flexible photoelectric-pole-electric integrated sensor and its fabrication method
By growing three-dimensional nanostructures and graphene layers on a flexible substrate and combining them with conductive electrodes, the fabrication challenge of flexible photoelectric and piezoelectric integrated sensors was solved, realizing flexible and efficient photoelectric and piezoelectric detection of the device.
Patent Information
- Application Number
- CN202211564937.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2022-12-07
- Publication Date
- 2025-12-02
- Estimated Expiration
- 2042-12-07
AI Technical Summary
Existing technologies make it difficult to fabricate flexible photoelectric and voltage integrated sensors based on zinc oxide materials.
A flexible photoelectric sensor was fabricated by growing a three-dimensional nanostructure on a flexible substrate, covering it with a graphene layer, and drawing it out through conductive electrodes, combined with a heavily doped N-type silicon oxide wafer and an indium gallium alloy electrode.
It achieves flexible bending of the device, enhances the device's flexibility and light trapping effect, and improves the performance of piezoelectric sensing and photoelectric detection, making it suitable for industrial application.
Smart Images
Figure CN115996622B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electronic device technology, specifically relating to a flexible opto-pole-electric integrated sensor and its fabrication method. Background Technology
[0002] The main working principle of a piezoelectric sensor is that when a dielectric material with a piezoelectric effect is deformed by an external force in a certain direction, it will generate polarization inside and generate positive and negative charges on its two opposite surfaces. When the external pressure is removed, it will return to a state without charge.
[0003] The main working principle of a photodetector is to excite photogenerated carriers in a semiconductor material by light. Under the influence of a built-in electric field, the photogenerated carriers diffuse and drift to form a photocurrent, thereby realizing the conversion of light to electricity and detection.
[0004] Piezoelectric sensors and photodetectors based on zinc oxide have been proven to have good performance, but how to make flexible photoelectric-piezoelectric integrated sensors based on zinc oxide has become a major challenge for researchers in the industry. Summary of the Invention
[0005] To address the technical problems existing in the prior art, the present invention aims to provide a flexible photoelectric-pole-electric integrated sensor and its fabrication method.
[0006] To achieve the above objectives and technical effects, the technical solution adopted by this invention is as follows:
[0007] A flexible photoelectric-voltage integrated sensor includes a flexible substrate, on which a three-dimensional nanostructure is grown in a junction region. The surface of the three-dimensional nanostructure is covered with several layers of graphene, which are led out through conductive electrodes. A matching bottom electrode is disposed at the bottom of the flexible substrate.
[0008] Furthermore, the flexible substrate is a heavily doped N-type silicon oxide wafer with a (100) orientation.
[0009] Furthermore, the three-dimensional nanostructure is a three-dimensional clustered zinc oxide array.
[0010] Furthermore, the conductive electrode is a gold electrode, the bottom electrode is an indium gallium alloy electrode, and the thicknesses of the conductive electrode and the bottom electrode are 50-500 nm, respectively.
[0011] Furthermore, the number of graphene layers is 1-10.
[0012] This invention also discloses a method for fabricating a flexible opto-pole-electric integrated sensor, comprising the following steps:
[0013] 1) Provide a silicon monoxide wafer, and thin it by wet etching or deep silicon etching to obtain a flexible substrate;
[0014] 2) Spin-coat photoresist onto the surface of the flexible substrate obtained in step 1), and then dry it.
[0015] 3) Expose the junction region using a mask, and then develop it to expose the junction region;
[0016] 4) Perform wet etching or dry etching on the flexible substrate obtained in step 3);
[0017] 5) Deposit a seed layer on the flexible substrate obtained in step 4);
[0018] 6) Remove the photoresist. After removing the photoresist, only the seed layer remains in the junction area. Then, the flexible substrate is annealed.
[0019] 7) Spin-coat electron beam photoresist onto the annealed flexible substrate and expose and develop it to obtain a hole array in the junction region. The spacing of the holes is controlled by the design of the mask pattern.
[0020] 8) Growing three-dimensional nanostructures in a pore array in a junction region;
[0021] 9) Remove any remaining electron beam photoresist;
[0022] 10) Coat the surface of the three-dimensional nanostructure with several layers of graphene;
[0023] 11) Use a mask to block the junction region, deposit gold on the surface of the graphene layer as a conductive electrode, and coat an indium gallium alloy electrode on the bottom of the flexible substrate as a bottom electrode.
[0024] Furthermore, in step 1), a 30%-60% KOH solution is used for wet etching to thin the substrate, the reaction temperature is 60-90℃, and the thickness of the thinned flexible substrate is 10-100μm.
[0025] Furthermore, in step 5), a ZnO seed layer with a thickness of 50-500 nm is deposited on the flexible substrate 5 obtained in step 4) using a magnetron sputtering coating machine, with a sputtering power of <100 W.
[0026] Furthermore, in step 6), the annealing temperature is 300℃ and the annealing time is 30-60 min.
[0027] Furthermore, in step 8), zinc oxide is grown in the pore array of the junction region using a hydrothermal growth method. The growth temperature is 100±5℃, the pressure is normal, and the growth time is 2-48h. The zinc oxide grown in a single pore is clustered zinc oxide. The solution used in the hydrothermal growth method is zinc nitrate hexahydrate with cyclohexamethylenetetramine.
[0028] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0029] This invention discloses a flexible photoelectric-pole-electric integrated sensor and its fabrication method. The device achieves flexible bending using a flexible substrate, and enhances its flexibility and light-trapping effect through the construction of a three-dimensional clustered zinc oxide array. A graphene layer is used as the top transparent electrode, which can effectively collect separated charges in the piezoelectric sensor. In the photodetector, graphene serves as part of a heterojunction for photogenerated carrier separation, achieving photoelectric detection. The density and length of the three-dimensional zinc oxide nanostructure in the device can be adjusted to regulate its piezoelectric performance, matching different pressure sensing requirements. The device's infrared light detection capability can be controlled by adjusting the number of graphene layers. This invention achieves the construction of a photoelectric-pole-electric integrated sensor with a simple process, suitable for industrial application. Attached Figure Description
[0030] Figure 1 This is a schematic diagram of the structure of the present invention;
[0031] Figure 2 This is a flowchart of the present invention;
[0032] Figure 3 This is a scanning electron microscope image of the present invention. Detailed Implementation
[0033] The present invention will now be described in detail so that its advantages and features can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.
[0034] The following provides a brief overview of one or more aspects to offer a basic understanding of them. This overview is not an exhaustive summary of all conceived aspects, nor is it intended to identify key or decisive elements of all aspects, nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form to prepare for the more detailed descriptions that follow.
[0035] like Figure 1-3 As shown, a flexible photoelectric integrated sensor includes a flexible substrate 5, a three-dimensional nanostructure grown in a junction region on the surface of the flexible substrate 5, a surface silicon oxide 2 formed at the edge of the junction region, the three-dimensional nanostructure preferably being a three-dimensional clustered zinc oxide array 3, the surface of the three-dimensional clustered zinc oxide array 3 being covered with several layers of graphene 4, the graphene layers 4 being placed on the surface silicon oxide 2 and led out through a conductive electrode 1, and a matching bottom electrode 6 being disposed at the bottom of the flexible substrate 5.
[0036] A method for fabricating a flexible opto-pole-electric integrated sensor includes the following steps:
[0037] 1) A silicon monoxide wafer is provided, and it is thinned by wet etching with an alkaline solution or by deep silicon etching to obtain a flexible substrate 5. The silicon oxide layer should be protected during the reaction. When using wet etching, KOH solution is preferably used as the alkaline solution, with a concentration of 30%-60%, preferably 50%, and the reaction temperature is 60-90℃. The final silicon wafer thickness is 10-100μm.
[0038] 2) Spin-coat photoresist onto the surface of the flexible substrate 5 obtained in step 1), using positive photoresist, and dry it after spin coating. The drying conditions are 100±5℃ for >1min.
[0039] 3) Use a mask to expose the junction area. The exposure time and the area of the junction area can be flexibly set according to actual needs. After exposure, develop the mask to expose the junction area.
[0040] 4) The flexible substrate 5 obtained in step 3) is wet-etched using HF solution or dry-etched using RIE until all silicon oxide in the junction region disappears.
[0041] 5) Deposit a ZnO seed layer with a thickness of 50-500 nm on the flexible substrate 5 obtained in step 4) using a magnetron sputtering coating machine, with a sputtering power of <100 W;
[0042] 6) Use acetone to soak and remove the photoresist. After removing the photoresist, only the ZnO seed layer remains in the junction area. Then, the flexible substrate 5 is annealed. The purpose of annealing is to improve the crystal quality of the ZnO seed layer. The annealing temperature is 300℃ and the annealing time is 30-60min.
[0043] 7) Spin-coat electron beam photoresist onto the annealed flexible substrate 5, using positive photoresist, and perform exposure and development to obtain a hole array in the junction region. The spacing of the holes can be controlled by the design of the mask pattern.
[0044] 8) Zinc oxide is grown in the junction hole array using a hydrothermal growth method to form a three-dimensional cluster zinc oxide array 3. Due to the incomplete fit between the (100)-axis silicon and zinc oxide lattice, the zinc oxide grown in a single hole is a cluster zinc oxide. In this step, the solution used for hydrothermal growth is zinc nitrate hexahydrate with cyclohexanethyltetramine, the growth temperature is 100±5℃, the pressure is normal, and the growth time is 2-48h.
[0045] 9) Remove the remaining electron beam photoresist by soaking in ethanol and acetone respectively;
[0046] 10) The graphene layer 4 is transferred to the junction surface using the standard PMMA transfer method. The area of the graphene layer 4 should be larger than the area of the junction region and cover the surface of the three-dimensional clustered zinc oxide array 3. The number of graphene layers 4 affects the device's ability to detect infrared light and its conductivity. It is recommended that the number of layers be 1-10, preferably 3.
[0047] 11) Use a mask to block the junction region, deposit gold on the surface around the graphene layer 4 as conductive electrode 1, the thickness of conductive electrode 1 is 50-500nm, and coat an indium gallium alloy electrode with a thickness of 50-500nm on the bottom of the flexible substrate 5 as bottom electrode 6.
[0048] The working principle of this invention is as follows:
[0049] Piezoelectric part: Under the action of external force or the deformation caused by substrate bending, the clustered zinc oxide expands outward and deforms. Due to the non-centrosymmetry of the crystal structure, the two ends of the clustered zinc oxide will generate positive and negative charges. The positive and negative charges are captured by the graphene layer 4 and the heavily doped silicon covering the surface, respectively, and are led out by the conductive electrode 1 to form an induced current.
[0050] In the optoelectronic section: Graphene possesses excellent electrical conductivity and exhibits good light absorption, particularly in the infrared band, especially communication wavelengths. Graphene layer 4 covers the surface of clustered zinc oxide, forming wrinkles that effectively trap light. When infrared light is incident, graphene layer 4 generates photogenerated carriers, which separate into electrons and holes in the heterojunction constructed from n-type zinc oxide and p-type graphene. These electrons and holes are captured and discharged by the bottom heavily doped silicon (with electrode 6) and the top graphene layer 4 (with conductive electrode 1), respectively. Similarly, when ultraviolet light is incident, it can generate photogenerated carriers in the clustered zinc oxide, which can also be separated and collected by the heterojunction to generate current, thus achieving photoelectric detection.
[0051] Depend on Figure 3 It can be seen that the surface of the three-dimensional cluster zinc oxide array 3 is equipped with a graphene layer 4 and forms a good light-trapping wrinkled structure.
[0052] Thanks to the extremely thin flexible substrate 5, the sensor device can achieve good flexibility. Through reasonable structural design, the device can realize photoelectric and piezoelectric integrated detection, providing a blueprint for the further development of wearable devices.
[0053] Example 1
[0054] like Figure 1-3As shown, a flexible photoelectric integrated sensor includes a flexible substrate 5, a three-dimensional clustered zinc oxide array 3 grown on the surface junction region of the flexible substrate 5, a number of graphene layers 4 covering the surface of the three-dimensional clustered zinc oxide array 3, the graphene layers 4 being attached to the surface silicon oxide 2 at the edge of the junction region on the surface of the flexible substrate 5 and led out through a conductive electrode 1, and a matching indium gallium alloy electrode 6 being disposed at the bottom of the flexible substrate 5 as a bottom electrode.
[0055] A method for fabricating a flexible opto-pole-electric integrated sensor includes the following steps:
[0056] 1) Provide a heavily doped N-type silicon oxide wafer with a crystal orientation of (100). Thin the heavily doped N-type silicon oxide wafer by wet etching with KOH solution or by deep silicon etching to obtain a flexible substrate 5. The silicon oxide layer should be protected during the reaction. When using wet etching, the concentration of KOH solution is 50%, the reaction temperature is 90℃, and the final silicon wafer thickness is 100μm.
[0057] 2) Spin-coat photoresist onto the surface of the flexible substrate 5 obtained in step 1), using positive photoresist, at a spin coating speed of 800 rpm, and then dry it at 100°C for 1 min.
[0058] 3) Expose the junction area using a mask for 0.2 seconds. The junction area here is a circle with a diameter of 2 mm. After exposure, develop the image to expose the junction area. It should be noted that the exposure time is related to the equipment used and users can set it flexibly according to actual needs. There is no area requirement for the junction area.
[0059] 4) The flexible substrate 5 obtained in step 3) is wet-etched using a 5% HF solution or dry-etched using RIE until all silicon oxide in the junction region disappears.
[0060] 5) A ZnO seed layer with a thickness of 50 nm is deposited on the flexible substrate 5 obtained in step 4) using a magnetron sputtering coating machine with a sputtering power of <100 W;
[0061] 6) Use acetone to soak and remove the photoresist. After removing the photoresist, only the ZnO seed layer remains in the junction area. Then, the flexible substrate 5 is annealed. The purpose of annealing is to improve the crystal quality of the ZnO seed layer. The annealing temperature is 300℃ and the annealing time is 30min.
[0062] 7) Spin-coat electron beam photoresist onto the annealed flexible substrate 5, using positive photoresist, and perform exposure and development to obtain a hole array in the junction region. The spacing of the holes can be controlled by the design of the mask pattern.
[0063] 8) Zinc oxide was grown in the junction pore array using a hydrothermal growth method to form a three-dimensional cluster zinc oxide array 3. Due to incomplete lattice fit, the zinc oxide grown in a single pore was clustered zinc oxide. In this step, the solution used for the hydrothermal growth method was zinc nitrate hexahydrate with cyclohexamethylenetetramine, the growth temperature was 100℃, the pressure was normal, and the growth time was 24h.
[0064] 9) Remove the remaining electron beam photoresist by soaking in ethanol and acetone respectively;
[0065] 10) The graphene layer 4 is transferred to the junction surface using the standard PMMA transfer method. The area of the graphene layer 4 should be larger than the area of the junction region and cover the surface of the three-dimensional clustered zinc oxide array 3. The number of graphene layers 4 affects the device's ability to detect infrared light and its conductivity. It is recommended that the number of layers be 1-10, preferably 3.
[0066] 11) Use a mask to block the junction region, deposit a layer of gold on the surface of the graphene layer 4 as the top conductive electrode 1 with a thickness of 100nm, and coat the bottom of the flexible substrate 5 with an indium gallium alloy electrode with a thickness of 50-500nm as the bottom electrode 6.
[0067] Any parts or structures not specifically described in this invention can be made using existing technologies or products, and will not be elaborated upon here.
[0068] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.
Claims
1. A method for fabricating a flexible photoelectric-pole-electric integrated sensor, characterized in that, Includes the following steps: 1) Provide a silicon monoxide wafer, and thin it by wet etching or deep silicon etching to obtain a flexible substrate; 2) Spin-coat photoresist onto the surface of the flexible substrate obtained in step 1), and then dry it. 3) Expose the junction region using a mask, and then develop it to expose the junction region; 4) Perform wet etching or dry etching on the flexible substrate obtained in step 3); 5) Deposit a seed layer on the flexible substrate obtained in step 4); 6) Remove the photoresist. After removing the photoresist, only the seed layer remains in the junction area. Then, the flexible substrate is annealed. 7) Spin-coat electron beam photoresist onto the annealed flexible substrate and expose and develop it to obtain a hole array in the junction region. The spacing of the holes is controlled by the design of the mask pattern. 8) Growing three-dimensional nanostructures in a pore array in a junction region; 9) Remove any remaining electron beam photoresist; 10) Cover the surface of the three-dimensional nanostructure with several layers of graphene; 11) Use a mask to block the junction region, deposit gold on the surface of the graphene layer as a conductive electrode, and coat an indium gallium alloy electrode on the bottom of the flexible substrate as a bottom electrode.
2. The method for fabricating a flexible opto-pole-electric integrated sensor according to claim 1, characterized in that, The flexible substrate is a heavily doped N-type silicon oxide wafer with a (100) orientation.
3. The method for fabricating a flexible opto-pole-electric integrated sensor according to claim 1, characterized in that, The three-dimensional nanostructure is a three-dimensional clustered zinc oxide array.
4. The method for fabricating a flexible opto-pole-electric integrated sensor according to claim 1, characterized in that, The conductive electrode is made of gold, and the bottom electrode is made of indium gallium alloy. The thicknesses of the conductive electrode and the bottom electrode are 50-500 nm, respectively.
5. The method for fabricating a flexible opto-pole-electric integrated sensor according to claim 1, characterized in that, The number of graphene layers is 1-10.
6. The method for fabricating a flexible opto-pole-electric integrated sensor according to claim 1, characterized in that, In step 1), a 30%-60% KOH solution is used for wet etching to thin the substrate. The reaction temperature is 60-90℃, and the thickness of the thinned flexible substrate is 10-100μm.
7. The method for fabricating a flexible opto-pole-electric integrated sensor according to claim 1, characterized in that, In step 5), a ZnO seed layer with a thickness of 50-500 nm is deposited on the flexible substrate obtained in step 4) using a magnetron sputtering coating machine with a sputtering power of <100 W.
8. The method for fabricating a flexible opto-pole-electric integrated sensor according to claim 1, characterized in that, In step 6), the annealing temperature is 300℃ and the annealing time is 30-60min.
9. The method for fabricating a flexible opto-pole-electric integrated sensor according to claim 1, characterized in that, In step 8), zinc oxide is grown in the pore array of the junction region using a hydrothermal growth method. The growth temperature is 100±5℃, the pressure is normal, and the growth time is 2-48h. The zinc oxide grown in a single pore is clustered zinc oxide. The solution used in the hydrothermal growth method is zinc nitrate hexahydrate with cyclohexamethylenetetramine.
10. The flexible photoelectric-pole-electric integrated sensor prepared by the method of any one of claims 1-9 is characterized in that, The flexible photoelectric-voltage integrated sensor includes a flexible substrate, on which a three-dimensional nanostructure is grown in a junction region. The surface of the three-dimensional nanostructure is covered with several layers of graphene, which are led out through conductive electrodes. A matching bottom electrode is disposed at the bottom of the flexible substrate.