A graphene-based piezoresistive vacuum gauge and a manufacturing method thereof

Abstract

The present invention relates to the field of pressure sensors, and discloses a graphene-based piezoresistive vacuum gauge, a plurality of graphene sensor elements, including a plurality of stacked graphene sheets; a carrier, including a flexible carrier, the flexible carrier is coated on the outer surface of the graphene sensor element and is tightly fitted with the graphene sensor element; an electrode, the electrode is connected to the outer surface of the graphene sensor element to form a circuit for monitoring current. The present invention also discloses a method for making a graphene-based piezoresistive vacuum gauge, including making a graphene sensor element, connecting electrodes and carrier wrapping. The present invention provides a graphene-based piezoresistive vacuum gauge and a method for making the same, which uses a graphene sensor element to measure vacuum degree, and has the advantages of high sensitivity, low cost, fast response speed, small measurement error, etc., and has broad market application value and prospects.

Description

Technical Field

[0001] The present invention relates to the field of pressure sensors, and in particular to a graphene-based piezoresistive vacuum gauge and a manufacturing method thereof. Background Art

[0002] Vacuum technology is widely used in many industries and scientific research, such as semiconductor technology, surface engineering and space science. Therefore, accurate measurement of vacuum pressure is crucial for advanced research and production. The vacuum gauges commonly used in the industry include capacitive, thermal conductive and ionization types. For capacitive direct measurement vacuum gauges, the pressure difference between vacuum and atmospheric environment can be measured very accurately, but the measurable vacuum range is limited to three to four orders of magnitude of the vacuum range (for example, 10 -3 -1, 1-1000, 10 -1 -100Torr), but it is difficult to measure below 10 -5 Torr pressure. The other two most commonly used vacuum gauges are thermal conductivity and ionization, with pressure measurement ranges of 1-10 -4 Torr and 10 -2 -10 -12 Torr. The measurement errors of these vacuum gauges are very high, with the error of thermal conductivity vacuum gauges being about 30% and that of ionization vacuum gauges exceeding 10%. In addition, the current vacuum sensors are large in size and high in power, making it difficult to achieve wireless measurement or measurement of small cavities. Current vacuum gauges cannot directly measure the speed at which gas molecules diffuse from outside the cavity to inside the cavity. Therefore, it is urgent to develop a vacuum pressure gauge with a micro-nano structure, low cost and high sensitivity. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] The purpose of the present invention is to provide a graphene-based piezoresistive vacuum gauge and a method for manufacturing the same, so as to solve the problems of low measurement sensitivity, large error, high cost, large footprint and high energy consumption of vacuum gauges in the prior art.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, the present invention provides a graphene-based piezoresistive vacuum gauge, which is characterized by comprising:

[0007] A plurality of graphene sensing elements, including a plurality of stacked graphene sheets;

[0008] A carrier, comprising a flexible carrier, wherein the flexible carrier is coated on the outer surface of the graphene sensor element and is closely attached to the graphene sensor element;

[0009] An electrode is connected to the outer surface of the graphene sensor element to form a loop for monitoring current.

[0010] Wherein, the carrier also includes a rigid carrier, and the flexible carrier is adhered to the rigid carrier or placed between two pieces of the rigid carrier.

[0011] Wherein, the electrodes include wires led out through metal interconnections or sputtered metal electrodes.

[0012] Wherein, the graphene sensor element is located at the mechanical center of the flexible carrier.

[0013] Wherein, the graphene sensor element is one or more arrays.

[0014] The multiple graphene sheets are stacked in an aligned manner or staggered manner.

[0015] Wherein, the graphene sheet is a micro-nano structure.

[0016] The graphene sensor element further comprises a positioning device and a lead-out device, wherein the positioning device is used to position the graphene sheet, and the electrode is connected to the outer surface of the graphene sensor element through the lead-out device to form a loop for monitoring current.

[0017] The present invention also discloses a method for manufacturing a graphene-based piezoresistive vacuum gauge, which is characterized by comprising:

[0018] S1. Using chemical method and laser direct writing method to prepare stacked graphene sheets to form graphene sensing elements;

[0019] S2, making electrodes from wires derived from metal interconnects and sputtered metal electrodes, and connecting them to the outer surface of the graphene sensor element;

[0020] S3. Wrap the flexible carrier on the outer surface of the graphene sensor element and fit it tightly with the graphene sensor element.

[0021] Among them, it also includes:

[0022] S4. Adhere the flexible carrier to the rigid carrier or place the flexible carrier between two rigid carriers.

[0023] (III) Beneficial effects

[0024] The present invention provides a graphene-based piezoresistive vacuum gauge and a manufacturing method thereof, which uses a graphene sensor element to measure the vacuum degree, and has the advantages of high sensitivity, low cost, fast response speed, small measurement error, etc., and has broad market application value and prospects. The present invention can accurately and quickly measure the vacuum pressure; and the use of a graphene sheet structure can greatly reduce the tailing of the response time; it can also improve the durability of the vacuum gauge, and the power loss is also lower; it is suitable for thin and small devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the three-dimensional structure of a graphene-based piezoresistive vacuum gauge according to an embodiment of the present invention;

[0026] Figure 2 This is a schematic diagram of the front structure of a graphene-based piezoresistive vacuum gauge according to an embodiment of the present invention;

[0027] Figure 3 This is a schematic diagram of a top view of a graphene-based piezoresistive vacuum gauge according to an embodiment of the present invention;

[0028] Figure 4 The present invention is a schematic diagram of an array structure of a graphene-based piezoresistive vacuum gauge according to an embodiment of the present invention.

[0029] In the figure, 1. Graphene sensor element; 2. Carrier; 3. Electrode. DETAILED DESCRIPTION

[0030] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0031] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0032] like Figure 1 As shown, several graphene sensing elements 1 include multiple stacked graphene sheets;

[0033] The carrier 2 includes a flexible carrier, which is coated on the outer surface of the graphene sensor element 1 and is closely attached to the graphene sensor element 1;

[0034] Electrode 3, which is connected to the outer surface of the graphene sensor element 1, forms a loop for monitoring current.

[0035] Specifically, a plurality of stacked graphene sheets are used to form a graphene sensor element 1. When the carrier 2 is subjected to external pressure, the carrier 2 transfers the force load to the graphene sensor element 1. The graphene sheets in the graphene sensor element 1 are subjected to force to change the spacing between the graphene sheets, resulting in compression deformation of the graphene sensor element. Since the graphene sensor element has a high resistance strain sensitivity coefficient, the deformation of the graphene sensor element will cause its resistance to change. The electrodes are connected to the two ends of the graphene sensor element to form a loop for monitoring the current. When the resistance of the graphene sensor element changes, the monitoring current in the loop changes, thereby measuring the ambient air pressure. Among them, the structure of stacked graphene sheets can produce a more sensitive response to pressure, with smaller measurement errors and greatly reduced size; the flexible carrier can be a cubic structure or a thin film. The flexible carrier should have the characteristics of plasticity, insulation, and excellent elastic deformation ability. The flexible carrier can not only transmit the force load, but also protect the graphene sensor element from external environmental pollution and extend the service life of the vacuum gauge. Specifically, the flexible carrier can be made of PDMS (polydimethylsiloxane polymer material), woven fabric, etc. The gaps between the graphene sheets can seal a certain amount of air, or can be evacuated. Adjusting the air pressure between the graphene sheets can play a role in adjusting the range of the vacuum meter.

[0036] The present invention adopts a graphene sheet structure to greatly reduce the tailing of the response time, because this structure reduces the diffusion path of gas molecules, and the path is based on the nanometer level; the use of a graphene sheet structure can improve the durability of the vacuum gauge and reduce power loss, because when the graphene sheet is deformed due to changes in gas pressure, the movement of the graphene sheet is based on the nanometer level.

[0037] The present invention provides a graphene-based piezoresistive vacuum gauge and a manufacturing method thereof, which uses a graphene sensor element to measure the vacuum degree, and has the advantages of high sensitivity, low cost, fast response speed, small measurement error, etc., and has broad market application value and prospects. The present invention can accurately and quickly measure the vacuum pressure; and by using the graphene sheet stacking method, the reaction response speed is very fast, and the tailing of the reaction time is greatly reduced, the sensitivity is significantly improved, and the lower limit of the range is significantly reduced, so that lower air pressure can be measured, and the measurement is more accurate; the volume and power consumption of the vacuum gauge stacked with graphene sheets are very small, and it can be used in thin and small devices.

[0038] The carrier 2 also includes a rigid carrier, the flexible carrier is adhered to the rigid carrier or placed between two rigid carriers, and the rigid carrier can not only transfer the load but also provide support for the vacuum gauge of the present invention. Specifically, the material of the rigid carrier is a glass substrate, a VCD disk, etc.

[0039] The electrode 3 includes a wire led out through a metal interconnection or a sputtered metal electrode.

[0040] Preferably, the material of the metal interconnection is copper, silver or gold.

[0041] The graphene sensor element 1 is located at the mechanical center of the flexible carrier to ensure more accurate measurement.

[0042] like Figure 1 , Figure 2 , Figure 3 and Figure 4 As shown, the graphene sensor element 1 is one or more arrays. Preferably, multiple graphene sheets are stacked in an aligned manner or staggered manner. Figure 1 As shown, there are three graphene sensor elements 1, namely, left, middle and right. The graphene sensor element 1 in the middle overlaps with the graphene sensor elements 1 on its left and right. Figure 1 In the figure, three graphene sensor elements 1 are arranged in an array, and the graphene sheets have a structure of being stacked in an aligned manner or staggered in an aligned manner. Figure 2 As shown, it is a structure in which each graphene sheet is staggered and stacked. Figure 2 As shown, a plurality of graphene sensor elements 1 are arranged in an array, and the graphene sheets have a structure of being stacked in an aligned manner or staggered in an aligned manner. Figure 4 As shown, the graphene sensor elements 1 are divided into two rows of arrays, and each row has five graphene sensor elements 1 .

[0043] The graphene sensor element 1 further includes a positioning device and a lead-out device. The positioning device is used to position the graphene sheet. The electrode 3 is connected to the outer surface of the graphene sensor element 1 through the lead-out device to form a loop for monitoring current.

[0044] Among them, graphene sheets are micro-nano structures.

[0045] The present invention also discloses a method for manufacturing a graphene-based piezoresistive vacuum gauge, which is characterized by comprising:

[0046] S1. Using chemical method and laser direct writing method to prepare stacked graphene sheets to form graphene sensing elements;

[0047] S2, making electrodes from wires derived from metal interconnects and sputtered metal electrodes, and connecting them to the outer surface of the graphene sensor element;

[0048] S3. Wrap the flexible carrier on the outer surface of the graphene sensor element and fit it tightly with the graphene sensor element.

[0049] Specifically, the chemical method for preparing stacked graphene sheets includes:

[0050] (1) Sputtering electrodes on a substrate;

[0051] (2) Place 1 g of carbon nanotubes in an ice bath, then add 150 ml of H2SO4 (98%) and 20 ml of H3PO4 (85%), and then add 12 g of KMnO4;

[0052] (3) After standing for 10 minutes, the mixture was heated to 45°C and stirred for 24 hours;

[0053] (4) Add 30 ml of distilled water, let stand for 30 minutes, and then add H2O2 until the bubbles in the mixture disappear;

[0054] (5) Separate using a centrifuge and wash three times with 5% HCl;

[0055] (6) The residue is then dissolved with an appropriate amount of HCl and separated using a centrifuge, and this process is repeated until the supernatant is slightly yellowish brown;

[0056] (7) Dialysis with distilled water to remove impurities;

[0057] (8) Mix 5 ml of the sample with 1 ml of hydrazine solution, then drop an appropriate amount of the mixture between the electrodes on the substrate, dry at 60°C, and then heat at 200°C in air for 1 h or at 450°C in vacuum for 1 h.

[0058] Preparation of stacked graphene sheets by laser direct writing:

[0059] A film is formed on the substrate using a solution film forming method, and then a laser of appropriate power is used for direct writing to carve out a certain shape, and then an electrode is formed using silver paste or the like.

[0060] Among them, it also includes:

[0061] S4. Adhere the flexible carrier to the rigid carrier or place the flexible carrier between two rigid carriers.

[0062] The present invention provides a graphene-based piezoresistive vacuum gauge and a manufacturing method thereof, which uses a graphene sensor element to measure the vacuum degree, and has the advantages of high sensitivity, low cost, fast response speed, small measurement error, etc., and has broad market application value and prospects. The present invention can accurately and quickly measure the vacuum pressure; and the use of a graphene sheet structure can greatly reduce the tailing of the response time; it can also improve the durability of the vacuum gauge, and the power loss is also lower; it is suitable for thin and small devices.

[0063] 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 graphene-based piezoresistive vacuum gauge, characterized in that: include: A plurality of graphene sensing elements (1), comprising a plurality of stacked graphene sheets; A carrier (2) comprising a flexible carrier, wherein the flexible carrier is coated on the outer surface of the graphene sensor element (1) and is closely attached to the graphene sensor element (1); An electrode (3), the electrode (3) being connected to the outer surface of the graphene sensor element (1) to form a circuit for monitoring current; The graphene sensor element (1) is a plurality of arrays, the plurality of graphene sheets have a structure of being stacked in an aligned manner or in a staggered manner, and there are gaps between the plurality of graphene sheets.

2. The graphene-based piezoresistive vacuum gauge according to claim 1, characterized in that: The carrier (2) also includes a rigid carrier, and the flexible carrier is adhered to the rigid carrier or placed between two pieces of the rigid carrier.

3. The graphene-based piezoresistive vacuum gauge according to claim 1, characterized in that: The electrode (3) comprises a wire led out through a metal interconnect or a sputtered metal electrode.

4. The graphene-based piezoresistive vacuum gauge according to claim 1, characterized in that: The graphene sensor element (1) is located at the mechanical center of the flexible carrier.

5. The graphene-based piezoresistive vacuum gauge according to claim 1, characterized in that: The graphene sheet is a micro-nano structure.

6. The graphene-based piezoresistive vacuum gauge according to claim 1, characterized in that: The graphene sensor element (1) further comprises a positioning device and a lead-out device, wherein the positioning device is used to position the graphene sheet, and the electrode (3) is connected to the outer surface of the graphene sensor element (1) via the lead-out device to form a loop for monitoring current.

7. A method for manufacturing a graphene-based piezoresistive vacuum gauge according to any one of claims 1 to 6, characterized in that: include: S1. Using chemical method and laser direct writing method to prepare stacked graphene sheets to form graphene sensing elements; S2, making electrodes from wires derived from metal interconnects and sputtered metal electrodes, and connecting them to the outer surface of the graphene sensor element; S3. Wrap the flexible carrier on the outer surface of the graphene sensor element and fit it tightly with the graphene sensor element.

8. The method for manufacturing a graphene-based piezoresistive vacuum gauge according to claim 7, characterized in that: Also includes: S4. Adhere the flexible carrier to the rigid carrier or place the flexible carrier between two rigid carriers.

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