Detection device

Abstract

The utility model discloses a detection device, which comprises a detection unit and a processing unit, and is characterized in that the detection unit comprises a first electrode, a semiconductor nanowire array and a second electrode which are sequentially laminated; a first potential barrier height exists between the first electrode and the nanowire, a second potential barrier height exists between the second electrode and the nanowire, and the first potential barrier height is different from the second potential barrier height. Thus, when adsorption is carried out between the to-be-detected particles and the nanowires and the electronegativity of the to-be-detected particles and the nanowires is different, charge transfer occurs between the to-be-detected particles and the nanowires, and when the to-be-detected particles and the nanowires are desorbed, free charges generated by charge transfer occur in the nanowires. As the height of the first potential barrier is different from the height of the second potential barrier, a built-in electric field can be formed in the nanowire, so that free charges in the nanowire directionally move under the action of the built-in electric field, electric signals are output from the first electrode and the second electrode, and self-driving of the detection unit is realized.

Description

Technical Field

[0001] The utility model relates to the field of detection technology, in particular to a detection device. Background Art

[0002] Common detection devices mainly include two categories. One is traditional high-precision instruments, such as mass spectrometers, chromatographs, etc., which have high manufacturing and use costs, are generally large in size, and are inconvenient to use; the other is detection devices based on electrochemical principles, which are small in size, convenient and efficient, but the detection units in the detection devices often require external energy supply for detection, which limits their scope of application.

[0003] Therefore, how to realize the self-driving of the detection unit in the detection device has become a technical problem that needs to be solved urgently in this field. Utility Model Content

[0004] An embodiment of the present utility model provides a detection device for realizing self-driving of a detection unit in the detection device.

[0005] The embodiment of the present utility model provides a detection device, comprising: a detection unit and a processing unit, wherein the detection unit comprises: a first electrode, a semiconductor nanowire array, and a second electrode stacked in sequence;

[0006] The nanowires in the semiconductor nanowire array extend in a direction that is the arrangement direction of the first electrode and the second electrode; the second electrode is a mesh electrode; a first barrier height exists between the first electrode and the nanowires, and a second barrier height exists between the second electrode and the nanowires, wherein the first barrier height is different from the second barrier height;

[0007] Both the first electrode and the second electrode are connected to the processing unit, and the processing unit is used to: when the second electrode contacts the substance to be detected and receives the electrical signal output through the first electrode and the second electrode, determine the parameters of the substance to be detected based on the electrical signal; wherein the parameters include: at least one of: the type of the substance to be detected, the components of the substance to be detected, and the concentration of the substance to be detected.

[0008] The beneficial effects of the utility model are as follows:

[0009] A detection device provided by an embodiment of the present invention includes: a detection unit and a processing unit, the detection unit includes: a first electrode, a semiconductor nanowire array, and a second electrode stacked in sequence; the extension direction of the nanowires in the semiconductor nanowire array is the arrangement direction of the first electrode and the second electrode; the second electrode is a mesh electrode; there is a first potential barrier height between the first electrode and the nanowires, and there is a second potential barrier height between the second electrode and the nanowires, and the first potential barrier height is different from the second barrier height; the first electrode and the second electrode are both connected to the processing unit, and the processing unit is used to: when the second electrode contacts the substance to be detected and receives the electrical signal output through the first electrode and the second electrode, determine the parameters of the substance to be detected according to the electrical signal; wherein the parameters include: at least one of: the type of the substance to be detected, the component of the substance to be detected, and the concentration of the substance to be detected. In this way, adsorption occurs between the particles to be detected in the substance to be detected and the nanowires, and when the electronegativity of the particles to be detected and the nanowires are different, charge transfer will occur between the two. When the particles to be detected and the nanowires are desorbed, free charges generated by the charge transfer will appear inside the nanowires. Furthermore, since the height of the first potential barrier is different from the height of the second potential barrier, a built-in electric field will be formed in the nanowires, so that the free charges in the nanowires will move in a direction under the action of the built-in electric field, and output electrical signals from the first electrode and the second electrode. Then, the processing unit can identify the type of substance to be detected, determine the components and concentration of the substance to be detected through the electrical signal, thereby realizing the identification and detection of the substance to be detected; and the process of the detection unit generating the electrical signal is carried out spontaneously by the detection unit, without the need to set up additional devices to drive it, thereby realizing self-driving of the detection unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a schematic structural diagram of a detection device provided in an embodiment of the present utility model;

[0011] Figure 2 A top view of a detection unit provided in an embodiment of the present utility model;

[0012] Figure 3 This is a schematic structural diagram of another detection device provided in an embodiment of the present utility model;

[0013] Figure 4 The output characteristic curve of the detection unit provided in the embodiment of the present utility model;

[0014] Figure 5 This is the output curve of the detection unit provided in the embodiment of the present utility model when immersed in water;

[0015] Figure 6 Output current curves of the detection unit for different liquids to be detected provided in the embodiment of the present utility model;

[0016] Figure 7 This is a curve showing how the output current of the detection unit changes with humidity in an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The following is a detailed description of a specific embodiment of a detection device provided by an embodiment of the present invention, in conjunction with the accompanying drawings. It should be noted that the described embodiments are only a portion of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0018] The present invention provides a detection device, such as Figure 1 As shown, it includes: a detection unit and a processing unit CL, the detection unit includes: a first electrode 100, a semiconductor nanowire array 200, and a second electrode 300 stacked in sequence; the extension direction of the nanowires 201 in the semiconductor nanowire array 200 is the arrangement direction of the first electrode 100 and the second electrode 300; the second electrode 300 is a mesh electrode; wherein a first barrier height exists between the first electrode 100 and the nanowires 201, and a second barrier height exists between the second electrode 300 and the nanowires 201, and the first barrier height is different from the second barrier height;

[0019] The first electrode 100 and the second electrode 300 are both connected to the processing unit CL, which is used to: when the second electrode 300 contacts the substance to be detected and receives the electrical signal output through the first electrode 100 and the second electrode 300, determine the parameters of the substance to be detected based on the electrical signal; wherein the parameters include: at least one of: the type of substance to be detected, the components of the substance to be detected, and the concentration of the substance to be detected.

[0020] In this way, adsorption occurs between the particles to be detected in the substance to be detected and the nanowires, and when the electronegativity of the particles to be detected and the nanowires are different, charge transfer will occur between the two. When the particles to be detected and the nanowires are desorbed, free charges generated by the charge transfer will appear inside the nanowires. Furthermore, since the height of the first potential barrier is different from the height of the second potential barrier, a built-in electric field will be formed in the nanowires, so that the free charges in the nanowires will move in a direction under the action of the built-in electric field, and output electrical signals from the first electrode and the second electrode. Then, the processing unit can identify the type of substance to be detected, determine the components and concentration of the substance to be detected through the electrical signal, thereby realizing the identification and detection of the substance to be detected; and the process of the detection unit generating the electrical signal is carried out spontaneously by the detection unit, without the need to set up additional devices to drive it, thereby realizing self-driving of the detection unit.

[0021] It should be understood that the substance to be detected can be in gaseous or liquid state, and can be respectively referred to as the gas to be detected or the liquid to be detected, and the particles to be detected are molecules or ions in the substance to be detected, such as but not limited to: when the substance to be detected is air, the particles to be detected are water molecules in the air; when the substance to be detected is a carbonated beverage, the particles to be detected are carbonate ions in the carbonated beverage. The specific particle types are not limited here.

[0022] In addition, if Figure 2 As shown, Figure 2 for Figure 1 The top view of the detection unit, from Figure 2 The second electrode 300 configured as a mesh electrode can be clearly seen in the figure. The second electrode 300 includes a plurality of through holes K. The through holes K can connect the gaps between the nanowires 201 and the outside world, so that the particles to be detected in the outside world can enter the gaps and undergo adsorption and desorption processes with the nanowires 201 to achieve the output of electrical signals.

[0023] Alternatively, as Figure 2 As shown, the mesh electrode is formed by interweaving multiple wires D, and the width L1 of the wires D is not less than 0.5 mm and not more than 1.5 mm. It should be understood that when manufacturing the mesh electrode, multiple wires D can be first manufactured and then interwoven to form the mesh electrode. Alternatively, holes can be drilled in a planar electrode to form the mesh electrode. The mesh electrode thus formed can also be regarded as being formed by interweaving multiple wires D. The specific manufacturing method is not limited here.

[0024] In this way, the problem of excessive resistance caused by the small width of the wire can be avoided, the conductivity of the second electrode is improved, and thus the performance of the detection device is improved; it can also be avoided that the through hole is too small due to the large width of the wire is avoided, which is conducive to the particles to be detected entering the gap between the nanowires, thereby increasing the frequency of adsorption and desorption, and improving the output performance of the detection unit.

[0025] It should be understood that since the diameter of the nanowire is very small and the through hole is relatively large, the number of nanowires exposed in the through hole can be multiple. Figure 2 The figure is only for illustration and does not mean that each through hole includes only one nanowire.

[0026] Optionally, the interface between the first electrode and the nanowire is a Schottky contact, and the interface between the second electrode and the nanowire is a Schottky contact. In this way, while forming a Schottky contact and ensuring that the first barrier height and the second barrier height are different, the first barrier height and the second barrier height can be set to a variety of different values. Furthermore, due to the wide range of options for the first barrier height and the second barrier height, the range of materials for making the first electrode and the second electrode is widened, broadening the range of options for the first electrode and the second electrode and improving the manufacturing flexibility of the detection device.

[0027] Of course, one of the interfaces between the first electrode and the nanowire and the second electrode and the nanowire can be configured as an ohmic contact, while the other can be configured as a Schottky contact. In this case, the first barrier height and the second barrier height can be different, thereby enabling the detection unit to output an electrical signal and determine the parameters of the substance to be detected based on the electrical signal. The specific configuration of the interface between the first electrode and the nanowire and the interface between the second electrode and the nanowire can be selected according to actual needs and is not specifically limited here.

[0028] Optionally, the first electrode and the second electrode can be made of the same material. In this case, the first barrier height and the second barrier height can still be different. For example, when the nanowire is made of silicon carbide, one end of the nanowire is carbon aggregated and the other end is silicon aggregated. Therefore, when the first electrode and the second electrode are in contact with the two ends of the nanowire respectively, the contact interface will be different, thereby forming different first barrier heights and second barrier heights. Of course, the nanowire can also be made of a semiconductor material with an asymmetric structure such as zinc oxide or gallium nitride, which is not limited here. In this way, the first electrode and the second electrode can be made of the same material, which simplifies the production process of the detection device and reduces the production cost.

[0029] Among them, the production material of the first electrode includes but is not limited to: at least one of metal materials such as gold, silver, copper, stainless steel, titanium alloy, etc., and may also include a conductive glue formed by a metal material and a gel; the production material of the second electrode includes but is not limited to: at least one of metal materials such as gold, silver, copper, stainless steel, titanium alloy, etc., and may also include a conductive glue formed by a metal material and a gel; the production material of the nanowire includes but is not limited to: any one of semiconductor materials such as silicon carbide, zinc oxide, gallium nitride, silicon, polyacetylene, polystyrene, etc.

[0030] Optionally, the gaps between the nanowires are no less than 10 nm and no greater than 50 nm. This prevents the gaps between the nanowires from being too small, which would prevent the liquid from entering the gaps, and thus increases the frequency of adsorption and desorption, thereby increasing the intensity of the output electrical signal and improving the performance of the detection device. It also prevents the gaps between the nanowires from being too large, which would prevent the liquid from entering the gaps quickly, thereby increasing the duration of adsorption and desorption, allowing the detection unit to output electrical signals for a longer period of time and improving the practicality of the detection device.

[0031] Optionally, the diameter of the nanowire is not less than 10 nm and not more than 50 nm. This prevents breakage of the nanowire due to a too small diameter, thereby improving the reliability of the detection device. It also prevents a too small specific surface area due to a too large diameter of the nanowire, thereby increasing the number of particles to be detected that are adsorbed and desorbed from the nanowire, thereby increasing the output electrical signal of the detection unit and improving the anti-interference capability of the detection device.

[0032] Optionally, the nanowire length can be set to the micrometer level. This prevents the liquid from quickly filling the gap due to a too-short nanowire length, thereby increasing the duration of adsorption and desorption, and thus improving the practicality of the detection device. It also prevents the nanowire from breaking due to an excessively long nanowire length, thereby improving the reliability of the detection device.

[0033] Optionally, the surface of the nanowire is uneven and / or has cracks. In this way, when the liquid to be detected is applied to the second electrode of the detector, it is difficult to completely fill the liquid to be detected due to the uneven surface and / or cracks on the surface of the nanowire and the small gap, so that there is some air on the side of the gap away from the second electrode. When the liquid to be detected slowly penetrates into the gap, due to the surface tension of the liquid to be detected, the liquid to be detected and the nanowire are adsorbed on each other, and the penetration process will continuously compress the air in the gap, thereby generating a large pressure in the gap, which makes the air in the gap gradually escape to the area with relatively large defects and low pressure, and generate turbulence at the escape position. The flow of this turbulence in the gap will act on the liquid to be detected, thereby breaking the equilibrium state of mutual adsorption between the liquid to be detected and the nanowire, so that some of the particles to be detected in the liquid to be detected are desorbed from the nanowire. The desorbed particles to be detected can be adsorbed on the surface of the nanowire again and desorbed again under the action of turbulence, thereby outputting an electrical signal from the first electrode and the second electrode, realizing the detection of the liquid to be detected by the detection device.

[0034] Of course, the surface of the nanowire can also be a smooth surface. In this case, the particles to be detected can be desorbed by evaporation after being adsorbed on the surface of the nanowire, and then an electrical signal is output from the first electrode and the second electrode, so that the detector can detect the gas to be detected.

[0035] Alternatively, as Figure 3As shown, the detector further includes a semiconductor substrate 400, which is disposed between the first electrode 100 and the semiconductor nanowire array 200. Thus, if the structure formed by the semiconductor material within the detector is considered as a whole, it is referred to as a semiconductor structure. In this case, the semiconductor structure includes the semiconductor nanowire array 200 and the semiconductor substrate 400. The provision of the semiconductor substrate 400 increases the contact area between the semiconductor structure and the first electrode 100, thereby making the connection between the semiconductor structure and the first electrode more stable and improving the stability of the detection unit structure. Furthermore, the larger contact area can reduce current loss when flowing through the contact interface, thereby increasing the output current and enhancing the performance of the detection device.

[0036] It should be understood that the semiconductor nanowire array can be formed by, but is not limited to, micro-nano processing techniques such as photolithography, dry etching, electrochemical etching, and electrolytic deposition. When a semiconductor substrate is provided, the semiconductor nanowire array can be formed by etching on one side of the semiconductor layer, and the etching process does not penetrate the semiconductor layer. In this way, a semiconductor nanowire array can be formed on the etching side, and a semiconductor substrate can be formed on the other side. The semiconductor structure thus formed has high consistency, so that the performance of the semiconductor structure is better, and the performance of the detection device is improved. Of course, when a semiconductor substrate is provided, the semiconductor nanowire array can also be formed by electrolytic deposition on one surface of the semiconductor substrate. When a semiconductor substrate is not provided, a semiconductor layer can be provided on the first electrode, and then the semiconductor layer can be etched, and the etching is stopped when the first electrode is etched. In this way, a semiconductor nanowire array can be formed on the first electrode.

[0037] Furthermore, a semiconductor nanowire array can be fabricated using anodization electrochemical etching. This method, by applying a periodic pulse voltage, can produce a stress-free, free-state semiconductor nanowire array. The stress-free, free-state semiconductor nanowire array exhibits minimal adhesion between nanowires, thereby maintaining a good nanowire morphology and improving the reliability of the detection device. Of course, other fabrication methods can also be used to form stress-free, free-state semiconductor nanowire arrays, which are not limited here.

[0038] In short, no matter which process is used, as long as the semiconductor nanowire array can be formed, the specific manufacturing method of the semiconductor nanowire array can be selected according to actual needs and is not limited here.

[0039] In addition, if Figure 1 As shown, the detection unit also includes a first output terminal A connected to the first electrode 100, and a second output terminal B connected to the second electrode 300, so that the electrical signal generated by the detection unit can be output to the processing unit through the first output terminal A and the second output terminal B, thereby realizing the detection of the substance to be detected.

[0040] Of course, the detection unit may not be provided with the first output end and the second output end, but the processing unit may be directly connected to the first electrode and the second electrode respectively, which can simplify the structure of the detector and reduce the manufacturing cost.

[0041] The detection device provided by the embodiment of the utility model is explained below with reference to the accompanying drawings.

[0042] like Figure 4 As shown, Figure 4 is the output characteristic curve of the detection unit, from Figure 4 It can be seen that the output characteristic curve of the detection unit is not symmetrical. When the voltage is zero, there is still a weak current flowing through the detection unit, which indicates that there is an inherent built-in electric field in the detection unit. The built-in electric field is generated because the height of the first potential barrier is different from the height of the second potential barrier. Therefore, the detection unit can use the built-in electric field to output electrical signals, thereby realizing the detection of the substance to be detected and realizing self-driving of the detection unit.

[0043] like Figure 5 As shown, Figure 5 (a) is the output voltage curve when the detection unit is placed underwater and immersed for a period of time. Figure 5 (b) shows the curve of the voltage change across the capacitor when the first electrode and the second electrode are connected to the two ends of the same capacitor and the detection unit is placed underwater and immersed for a period of time. Figure 5 (c) is the output current curve when the detection unit is put into water and taken out after being immersed in water for a period of time. Figure 5 In (a), it can be seen that the output voltage is high when the detection unit is just placed underwater. This is because during the process of placing the detection unit underwater, the friction between the semiconductor nanowire array and water produces a strong charge transfer, resulting in a high output voltage. After the detection unit is placed underwater for a period of time, the output voltage tends to be stable. Figure 5 As can be seen in (b), when the detection unit is connected to an external capacitor, the capacitor can be charged; Figure 5 As can be seen in (c), friction generates a high output current when the detection unit is first placed underwater and when it is removed. While the detection unit is underwater, the output current is a steady DC current. This allows the detection unit to not only output an electrical signal to the processing unit to detect the substance being detected, but also, due to its steady output current, it can be used as a power generator to power other devices, broadening its application range.

[0044] The substances to be detected are respectively liquid to be detected and gas to be detected.

[0045] 1. When the substance to be detected is a liquid to be detected, the detection device can be called a liquid detection device.

[0046] The principle by which the liquid detection device can detect liquid parameters is as follows:

[0047] Contact stimulation process: When the semiconductor nanowire array in the detection unit comes into contact with the liquid to be detected, a triboelectric signal is generated due to the friction between the liquid to be detected and the semiconductor nanowire array;

[0048] Internal response process: Subsequently, during the continuous contact between the liquid to be detected and the semiconductor nanowire array, the particles to be detected in the liquid to be detected are continuously adsorbed and desorbed from the nanowires, which will generate continuous charge transfer and thus generate a continuous electrical signal.

[0049] The two processes of contact stimulation and internal response are reflected as two signal peaks on the output current curve, and the peak height and peak width of the signal peak are related to the type of particles to be detected in the liquid to be detected. In this way, after the first processor obtains the output current curve, it can be compared with the output current curves of various liquids stored in the database, so that the content of particles to be detected in the liquid to be detected can be judged according to the intensity of the signal peak, that is, the concentration of the liquid can be judged, and the type of particles to be detected in the liquid to be detected can be judged according to the shape of the signal peak, that is, the composition and type of the liquid can be judged.

[0050] For example, Figure 6 As shown, Figure 6 The output current curves when the liquid to be tested is milk, soda water, and pure water are shown in the figure. Figure 6 It can be seen from the figure that the output current curve changes periodically, and each cycle includes a period of time when the output current is zero. This is because the detection unit is repeatedly placed in and taken out of the liquid to be detected during the experiment, and it will be left to stand for a period of time each time it is taken out. The period when the output current is zero is the period when it is left to stand after being taken out, and the period when the output current is not zero is the period when the detection unit is placed in the liquid to be detected. Figure 6 It can be clearly seen that there are great differences in the signal peaks of different liquids to be detected, so that a single detection unit can be used to detect a variety of different types of liquids, and the detection results are highly accurate. The accuracy of the liquid detection device can be as high as 99.72%.

[0051] from Figure 6 It can also be seen that the total width of the two signal peaks corresponding to the contact stimulation and internal response processes is about 120 seconds, or two minutes. Therefore, the liquid detection device can obtain two signal peaks in a very short time, thereby realizing the detection of liquid parameters. The detection process is rapid and highly sensitive.

[0052] In addition, since the detection unit can be made of semiconductor materials and metal materials, and common semiconductor materials and metal materials with strong corrosion resistance and high stability can be selected, such as but not limited to silicon carbide and gold, the liquid detection device can be used to detect strong unknown liquids or detect dangerous components in mixed liquids.

[0053] 2. The substance to be detected is a gas to be detected. In this case, the detection device can be called a gas detection device.

[0054] When the gas detection device is used to detect the humidity of the air, it can be called a humidity detection device. The principle of the humidity detection device is: when the water molecules in the air come into contact with the nanowires, spontaneous adsorption and desorption caused by evaporation will occur, thereby generating an electrical signal. When the humidity of the air increases, the number of water molecules will also increase, and the adsorption and desorption process will also intensify, thereby generating a stronger electrical signal. When the humidity of the air decreases, the number of water molecules will also decrease, and the adsorption and desorption process will also weaken, and the electrical signal will decrease. Therefore, when the electrical signal is output to the processing unit, the processing unit can find the humidity corresponding to the current electrical signal according to the corresponding relationship between the stored humidity and the size of the electrical signal, thereby realizing the detection of humidity.

[0055] For example, Figure 7 As shown, Figure 7 This is the output current curve of the detection unit after long-term humidification using a humidifier. Figure 7 The percentage shown in represents the air humidity, from Figure 7 It can be seen that as the air humidity continues to increase, the output current also tends to increase, so that the processing unit can judge the size of the air humidity based on the output current and can perform detection under various humidity conditions.

[0056] Of course, when the gas detection device is used to detect other gases, such as but not limited to: the hydrogen chloride gas content in the gas tank, the concentration of natural gas in the natural gas pipeline, etc., its working principle is similar to that of detecting air humidity and will not be described in detail here.

[0057] Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if such modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention is intended to include such modifications and variations.

Claims

1. A detection device, characterized in that: include: A detection unit and a processing unit, wherein the detection unit comprises: a first electrode, a semiconductor nanowire array, and a second electrode stacked in sequence; The nanowires in the semiconductor nanowire array extend in a direction that is the arrangement direction of the first electrode and the second electrode; the second electrode is a mesh electrode; a first barrier height exists between the first electrode and the nanowires, and a second barrier height exists between the second electrode and the nanowires, wherein the first barrier height is different from the second barrier height; Both the first electrode and the second electrode are connected to the processing unit, and the processing unit is used to: when the second electrode contacts the substance to be detected and receives the electrical signal output through the first electrode and the second electrode, determine the parameters of the substance to be detected based on the electrical signal; wherein the parameters include: at least one of: the type of the substance to be detected, the components of the substance to be detected, and the concentration of the substance to be detected.

2. The detection device according to claim 1, wherein The interface between the first electrode and the nanowire is a Schottky contact, and the interface between the second electrode and the nanowire is a Schottky contact.

3. The detection device according to claim 1, wherein The material of the first electrode includes at least one of gold, silver, copper, stainless steel, and titanium alloy; Alternatively, the second electrode is made of at least one of gold, silver, copper, stainless steel, and titanium alloy.

4. The detection device according to claim 1, wherein The first electrode and the second electrode are made of the same material.

5. The detection device according to claim 1, wherein The nanowires are made of any one of silicon carbide, zinc oxide, gallium nitride, polyacetylene and polystyrene.

6. The detection device according to claim 1, wherein The surface of the nanowire is uneven and / or has cracks.

7. The detection device according to claim 1, wherein: The gap between the nanowires is not less than 10 nm and not more than 50 nm.

8. The detection device according to claim 1, wherein: The diameter of the nanowire is not less than 10 nm and not more than 50 nm.

9. The detection device according to claim 1, wherein: The mesh electrode is formed by interweaving a plurality of conductive wires, and the width of the conductive wires is not less than 0.5 mm and not more than 1.5 mm.

10. The detection device according to any one of claims 1 to 9, characterized in that: The substance to be detected is in gaseous or liquid state.

Images