Detection device

Abstract

The invention 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] This invention relates to the field of detection technology, and more particularly to a detection device. Background Technology

[0002] Common detection devices mainly fall into two categories. One category consists of traditional high-precision instruments, such as mass spectrometers and chromatographs, which have high manufacturing and usage costs and are generally large in size, making them inconvenient to use. The other category consists of detection devices based on electrochemical principles, which are smaller in size and convenient and efficient. However, the detection units in these devices often require an external energy supply to perform detection, which limits their applicability.

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

[0004] This invention provides a detection device for realizing the self-driving of the detection unit in the detection device.

[0005] This invention provides a detection device, including a detection unit and a processing unit, wherein the detection unit includes a first electrode, a semiconductor nanowire array, and a second electrode arranged in sequence.

[0006] The nanowires in the semiconductor nanowire array extend in the direction of the arrangement of the first electrode and the second electrode; the second electrode is a mesh electrode; there is a first barrier height between the first electrode and the nanowire, and a second barrier height between the second electrode and the nanowire, 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. The processing unit is used to: determine the parameters of the substance to be detected based on the electrical signal when the second electrode contacts the substance to be detected and receives the electrical signal output through the first electrode and the second electrode; wherein the parameters include at least one of the following: 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 this invention are as follows:

[0009] An embodiment of the present invention provides a detection device, comprising: a detection unit and a processing unit. The detection unit includes: a first electrode, a semiconductor nanowire array, and a second electrode stacked sequentially; 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; 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, which is used to: when the second electrode contacts a substance to be detected and receives an electrical signal output through the first electrode and the second electrode, determine 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 composition of the substance to be detected, and the concentration of the substance to be detected. Thus, adsorption occurs between the target particles and nanowires in the substance to be detected. When the target particles and nanowires have different electronegativity, charge transfer occurs between them. When the target particles and nanowires desorb, free charges generated due to charge transfer appear inside the nanowires. Furthermore, since the height of the first barrier is different from the height of the second barrier, a built-in electric field is formed in the nanowires. As a result, the free charges in the nanowires move directionally under the action of the built-in electric field and output electrical signals from the first and second electrodes. The processing unit can then identify the type of the target substance, determine its composition and concentration, and thus realize the identification and detection of the target substance. Moreover, the process of generating electrical signals by the detection unit is spontaneous, without the need for additional devices to drive it, thus realizing the self-driving of the detection unit. Attached Figure Description

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

[0011] Figure 2 This is a top view of a detection unit provided in an embodiment of the present invention;

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

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

[0014] Figure 5 This is the output curve of the detection unit provided in this embodiment of the invention when it is immersed in water;

[0015] Figure 6 The output current curves of the detection unit for different liquids to be detected are provided in the embodiments of the present invention.

[0016] Figure 7The curve showing the change of output current of the detection unit as a function of humidity is shown in the embodiment of the present invention. Detailed Implementation

[0017] The specific embodiments of a detection device provided by the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0018] This 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 sequentially. The extension direction of the nanowires 201 in the semiconductor nanowire array 200 is the same as the arrangement direction of the first electrode 100 and the second electrode 300. The second electrode 300 is a mesh electrode. There is a first barrier height between the first electrode 100 and the nanowires 201, and a second barrier height between the second electrode 300 and the nanowires 201. 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. The processing unit CL is used to: determine the parameters of the substance to be detected based on the electrical signal 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; wherein the parameters include at least one of the following: 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.

[0020] Thus, adsorption occurs between the target particles and nanowires in the substance to be detected. When the target particles and nanowires have different electronegativity, charge transfer occurs between them. When the target particles and nanowires desorb, free charges generated due to charge transfer appear inside the nanowires. Furthermore, since the height of the first barrier is different from the height of the second barrier, a built-in electric field is formed in the nanowires. As a result, the free charges in the nanowires move directionally under the action of the built-in electric field and output electrical signals from the first and second electrodes. The processing unit can then identify the type of the target substance, determine its composition and concentration, and thus realize the identification and detection of the target substance. Moreover, the process of generating electrical signals by the detection unit is spontaneous, without the need for additional devices to drive it, thus realizing the self-driving of the detection unit.

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

[0022] In addition, such as Figure 2 As shown, Figure 2 for Figure 1 Top view of the detection unit, from Figure 2 The second electrode 300, which is configured as a mesh electrode, can be clearly seen. The second electrode 300 includes multiple through holes K, which can connect the gaps between the nanowires 201 and the outside world. Thus, the particles to be detected from the outside world can enter the gaps and undergo adsorption and desorption processes with the nanowires 201, thereby realizing the output of electrical signals.

[0023] Optionally, such as Figure 2 As shown, the mesh electrode is formed by interlacing 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 the mesh electrode can be fabricated by first fabricating multiple wires D and then interlacing them to form the mesh electrode, or by drilling holes in a planar electrode to form a mesh electrode. The resulting mesh electrode can also be regarded as being formed by interlacing multiple wires D in terms of morphology. The specific fabrication method is not limited here.

[0024] In this way, excessive resistance due to too small wire width can be avoided, improving the conductivity of the second electrode and thus improving the performance of the detection device; it can also avoid the through-hole being too small due to too large wire width, which is conducive to the entry of the particles to be detected into the gaps 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 because the nanowires have a very small diameter while the vias are relatively large, the number of nanowires exposed within the vias can be multiple. Figure 2 The image is for illustrative purposes only and does not represent that each via contains 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 also a Schottky contact. Thus, while forming Schottky contacts and ensuring that the first and second barrier heights are different, the first and second barrier heights can be set to various different values. Furthermore, because there are many choices for the first and second barrier heights, the range of materials used to fabricate the first and second electrodes is broadened, increasing the selectable range of the first and second electrodes 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 set as an ohmic contact and the other as a Schottky contact. In this case, the heights of the first and second potential barriers can be different, thereby enabling the output of an electrical signal from the detection unit and determining the parameters of the substance to be detected based on the electrical signal. The specific settings of the interfaces between the first electrode and the nanowire, and the second electrode and the nanowire, can be selected according to actual needs and are not specifically limited here.

[0028] Optionally, the first and second electrodes can be made of the same material. In this case, it's still possible to achieve different first and second barrier heights. For example, when the nanowire is made of silicon carbide, one end of the nanowire is composed of carbon aggregates, and the other end is composed of silicon aggregates. Therefore, when the first and second electrodes contact the two ends of the nanowire respectively, the contact interfaces will be different, resulting in different first and second barrier heights. Of course, the nanowire can also be made of semiconductor materials with asymmetric structures, such as zinc oxide or gallium nitride, and is not limited here. Thus, using the same material to fabricate both the first and second electrodes simplifies the fabrication process of the detection device and reduces manufacturing costs.

[0029] The materials used to fabricate the first electrode include, but are not limited to, at least one of the following metals: gold, silver, copper, stainless steel, titanium alloy, etc., and may also include a conductive adhesive formed by metal materials and gel; the materials used to fabricate the second electrode include, but are not limited to, at least one of the following metals: gold, silver, copper, stainless steel, titanium alloy, etc., and may also include a conductive adhesive formed by metal materials and gel; the materials used to fabricate the nanowires include, but are not limited to, any one of the following semiconductor materials: silicon carbide, zinc oxide, gallium nitride, silicon, polyacetylene, polystyrene, etc.

[0030] Optionally, the gap between the nanowires is not less than 10 nm and not more than 50 nm. This prevents the liquid from being too small to enter the gap when the analyte is liquid and applied to the detection unit, thus increasing the frequency of adsorption and desorption and consequently increasing the strength of the output electrical signal and improving the performance of the detection device. It also prevents the liquid from entering the gap too quickly due to excessively large gaps, increasing the duration of adsorption and desorption, allowing the detection unit to output an electrical signal for a longer period 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 avoids nanowire breakage caused by too small a diameter, improving the reliability of the detection device. It also avoids nanowire breakage caused by too large a diameter, resulting in too small a specific surface area, increasing the number of detectable particles that can be adsorbed and desorbed with the nanowire, thereby improving the output electrical signal of the detection unit and enhancing the anti-interference capability of the detection device.

[0032] Optionally, the length of the nanowires can be set to the micrometer scale. This avoids the liquid to be detected from quickly filling the gap due to the nanowires being too short, thus increasing the duration of adsorption and desorption and improving the practicality of the detection device; it also avoids the nanowires from breaking due to their excessive length, thus improving the reliability of the detection device.

[0033] Optionally, the nanowires have an uneven surface and / or cracks. Thus, when the liquid to be tested is applied to the second electrode of the detector, due to the uneven surface and / or cracks in the nanowires and the small gaps, it is difficult to completely fill the gap with the liquid. Consequently, some air remains on the side of the gap furthest from the second electrode. As the liquid slowly permeates into the gap, due to the surface tension of the liquid, the liquid and nanowires are mutually adsorbed, and the permeation process continuously compresses the air within the gap, generating significant pressure. This causes the air to gradually escape to areas with relatively larger defects and lower pressure, creating turbulence at the escape points. This turbulence acts on the liquid, disrupting the equilibrium of mutual adsorption between the liquid and nanowires. This causes some of the particles in the liquid to desorb from the nanowires. The desorbed particles can then re-adsorb onto the surface of the nanowires and desorb again under the influence of turbulence, thereby outputting an electrical signal from the first and second electrodes, enabling the detection device to detect the liquid.

[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 to realize the detection of the gas to be detected by the detector.

[0035] Optionally, such as Figure 3As shown, the detector also 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, referred to as a semiconductor structure, then the semiconductor structure includes the semiconductor nanowire array 200 and the semiconductor substrate 400. By providing the semiconductor substrate 400, the contact area between the semiconductor structure and the first electrode 100 is increased, thereby making the connection between the semiconductor structure and the first electrode more stable, improving the stability of the detection unit structure. Furthermore, the larger contact area can reduce current loss when flowing through the contact interface, increasing the output current and enhancing the performance of the detection device.

[0036] It should be understood that semiconductor nanowire arrays can be formed, but are not limited to, through micro-nano fabrication processes such as photolithography, dry etching, electrochemical etching, and electrolytic deposition. When a semiconductor substrate is present, the semiconductor nanowire array can be formed as follows: etching is performed on one side of the semiconductor layer, without penetrating the semiconductor layer. This allows the semiconductor nanowire array to be formed on the etched side, while a semiconductor substrate is formed on the other side. The resulting semiconductor structure exhibits high consistency, leading to superior semiconductor performance and improved detection device performance. Alternatively, when a semiconductor substrate is present, the semiconductor nanowire array can also be formed by electrolytic deposition on one side of the semiconductor substrate. When no semiconductor substrate is present, a semiconductor layer can be deposited on top of the first electrode, and then the semiconductor layer can be etched until the first electrode is reached, at which point the etching stops, thus forming the semiconductor nanowire array on top of the first electrode.

[0037] Furthermore, semiconductor nanowire arrays can be fabricated using anodic oxidation electrochemical etching. This method, by applying periodic pulsed voltages, can create stress-free, free-state semiconductor nanowire arrays. The nanowires in stress-free, free-state semiconductor nanowire arrays exhibit less adhesion, thus maintaining a better 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; this is not a limitation.

[0038] In short, any process that can form a semiconductor nanowire array is acceptable. The specific fabrication method of the semiconductor nanowire array can be selected according to actual needs and is not limited here.

[0039] In addition, such as 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. In this way, 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 have a first output terminal and a second output terminal. Instead, the processing unit can be directly connected to the first electrode and the second electrode, which can simplify the structure of the detector and reduce the manufacturing cost.

[0041] The detection device provided in the embodiments of the present invention will be explained below with reference to the accompanying drawings.

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

[0043] like Figure 5 As shown, Figure 5 (a) shows the output voltage curve when the detection unit is submerged in water and immersed for a period of time. Figure 5 (b) shows the voltage change curves across the capacitor after the detection unit is submerged in water and immersed for a period of time, with the first and second electrodes connected to the two ends of the same capacitor, respectively. Figure 5 Image (c) shows the output current curve when the detection unit is submerged underwater and immersed for a period of time before being removed from the water. Figure 5 As can be seen in (a), the output voltage is high when the detection unit is first placed underwater. This is because the friction between the semiconductor nanowire array and the water during the underwater process generates strong charge transfer, resulting in a higher output voltage. After the detection unit is submerged for a period of time, the output voltage tends to stabilize. Figure 5 As can be seen in (b), when an external capacitor is connected to the detection unit, the capacitor can be charged; from Figure 5 As shown in (c), a large output current is generated due to friction when the detection unit is first placed underwater and when it is taken out of the water. While the detection unit is underwater, the output current is a stable direct current. Thus, the detection unit can not only output electrical signals to the processing unit to detect the substance to be tested, but also, because the output current of the detection unit is stable, it can also be used as a power generation device to power other equipment, thus broadening the application range of the detection unit.

[0044] The following sections will provide a detailed introduction to the substances to be tested, namely the liquid and the gas.

[0045] 1. If the substance to be tested is a liquid, the testing device can be called a liquid testing device.

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

[0047] Contact stimulation process: When the semiconductor nanowire array in the detection unit begins to come into contact with the liquid to be detected, a triboelectric signal will be 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 tested and the semiconductor nanowire array, the particles to be tested in the liquid to be tested and the nanowires are continuously adsorbed and desorbed, 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 in the output current curve as two signal peaks. The peak height and peak width of the signal peaks are related to the types of particles to be detected in the liquid. Thus, after the first processor obtains the output current curve, it can compare it with the output current curves of various liquids stored in the database. Therefore, the content of particles to be detected in the liquid can be determined based on the intensity of the signal peaks, that is, the liquid concentration can be determined. The types of particles to be detected in the liquid can be determined based on the shape of the signal peaks, that is, the composition and type of the liquid can be determined.

[0050] For example, such as Figure 6 As shown, Figure 6 The output current curves are shown for milk, soda water, and purified water, respectively. Figure 6 As can be seen, the output current curve changes periodically, and each cycle includes a period of zero output current. This is because the detection unit was repeatedly placed into and removed from the liquid being tested during the experiment, and was left to stand for a period of time after each removal. The period of zero output current corresponds to the period of standing after removal, while the period of non-zero output current corresponds to the period when the detection unit was placed into the liquid being tested. Figure 6 It is evident that the signal peaks of different liquids to be tested vary greatly, thus enabling the detection of multiple different types of liquids using a single detection unit, with high accuracy. The accuracy of the liquid detection device can reach up to 99.72%.

[0051] from Figure 6 It can also be seen that the total width of the two signal peaks corresponding to the two processes of contact stimulation and internal response is about 120 seconds, or two minutes. Thus, 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 and metal materials, and can be made of common semiconductor and metal materials with strong corrosion resistance and high stability, such as, but not limited to, silicon carbide and gold, the liquid detection device can be used to detect strong unknown liquids or detect hazardous components in mixed liquids.

[0053] 2. If the substance to be detected is a gas, the detection device can be called a gas detection device.

[0054] When a gas detection device is used to detect air humidity, it can be called a humidity detection device. The principle of the humidity detection device is as follows: when water molecules in the air come into contact with nanowires, they will undergo spontaneous adsorption and desorption caused by evaporation, thereby generating an electrical signal. When the air humidity increases, the number of water molecules also increases, thus intensifying the adsorption and desorption processes and generating a stronger electrical signal. When the air humidity decreases, the number of water molecules also decreases, thus weakening the adsorption and desorption processes and lowering the electrical signal. Therefore, when the electrical signal is output to the processing unit, the processing unit can find the humidity corresponding to the current electrical signal based on the stored correspondence between humidity and electrical signal magnitude, thereby realizing humidity detection.

[0055] For example, such as Figure 7 As shown, Figure 7 The output current curve of the detection unit is shown after prolonged humidification using a humidifier. Figure 7 The percentages shown represent air humidity, from Figure 7 As the air humidity increases, the output current also increases. Thus, the processing unit can determine the air humidity based on the output current and can perform detection under various humidity conditions.

[0056] Of course, when gas detection devices are used to detect other gases, such as, but not limited to, the hydrogen chloride content in gas storage tanks and the concentration of natural gas in natural gas pipelines, their working principle is similar to that when detecting air humidity, and will not be described in detail here.

[0057] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A detection device, characterized in that, include: The detection unit includes a detection unit and a processing unit, wherein the detection unit comprises: a first electrode, a semiconductor nanowire array, and a second electrode arranged in sequence; The nanowires in the semiconductor nanowire array extend in the direction of the arrangement of the first electrode and the second electrode; the second electrode is a mesh electrode; there is a first barrier height between the first electrode and the nanowire, and a second barrier height between the second electrode and the nanowire, 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. The processing unit is used to: determine the parameters of the substance to be detected based on the electrical signal when the second electrode contacts the substance to be detected and receives the electrical signal output through the first electrode and the second electrode; wherein the parameters include at least one of the following: 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 as described in claim 1, characterized in that, The interface between the first electrode and the nanowire is a Schottky contact, and the interface between the second electrode and the nanowire is also a Schottky contact.

3. The detection device as described in claim 1 or 2, characterized in that, The material used to manufacture the first electrode includes at least one of the following: gold, silver, copper, stainless steel, and titanium alloy; Alternatively, the material used to make the second electrode may include at least one of the following: gold, silver, copper, stainless steel, and titanium alloy.

4. The detection device according to any one of claims 1-3, characterized in that, The first electrode and the second electrode are made of the same material.

5. The detection device according to any one of claims 1-4, characterized in that, The nanowires are made of any one of the following materials: silicon carbide, zinc oxide, gallium nitride, polyacetylene, and polystyrene.

6. The detection device according to any one of claims 1-5, characterized in that, The nanowires have an uneven surface and / or have cracks on their surface.

7. The detection device according to any one of claims 1-6, characterized in that, The gap between the nanowires is not less than 10 nm and not more than 50 nm.

8. The detection device according to any one of claims 1-7, characterized in that, The diameter of the nanowire is not less than 10 nm and not more than 50 nm.

9. The detection device according to any one of claims 1-8, characterized in that, The mesh electrode is composed of multiple interwoven wires, the width of which is not less than 0.5 mm and not more than 1.5 mm.

10. The detection apparatus according to any one of claims 1-9, characterized in that, The substance to be detected is either gaseous or liquid.

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