Chemical gas sensor chip based on metal atomic cluster and adopting dielectrophoresis technology
Metal atom cluster sensor chips were prepared on silicon oxide substrates using dielectrophoresis technology, which solved the problems of insufficient stability and sensitivity of nanomaterials in sensors and achieved efficient and low-cost chemical gas detection.
Patent Information
- Application Number
- CN202510814075.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-17
- Publication Date
- 2025-09-16
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The quantum confinement effect of nanomaterials in existing chemical gas sensors is weakened, deposition technology makes it difficult to construct a uniform active layer, device manufacturing is complex and there are many noise sources, resulting in insufficient sensing stability and sensitivity.
The metal atom cluster sensor chip was prepared on a silicon oxide substrate using dielectrophoresis technology. Micro-nano electrodes were formed through electron beam exposure and ultraviolet lithography. Combined with dielectrophoresis technology, high-frequency pulse voltage was applied between the electrodes to assemble metal atom clusters and form an ordered conductive channel.
High-sensitivity chemical gas detection is achieved, costs are reduced, the preparation rate and stability of the sensor are improved, the gas adsorption efficiency and reaction efficiency are enhanced, and the sensitivity of the sensor is improved.
Smart Images
Figure CN120651923A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of gas detection, and in particular relates to a chemical gas sensor chip based on metal atom clusters using dielectrophoresis technology. Background Art
[0002] Chemical gas sensors play an irreplaceable role in monitoring trace amounts of hazardous gases, warning of explosive atmospheres, and analyzing biological metabolism. Existing sensors often rely on metal oxides, conductive polymers, or precious metal nanostructures as sensitive materials. In recent years, scientists have integrated various nanocluster materials into sensors, creating highly stable and sensitive sensors.
[0003] However, the main limitations of current technology stem from three dimensions: first, traditional nanomaterials (such as gold and silver nanoparticles with a particle size >3nm) are weakened due to the quantum confinement effect, and the surface electronic state distribution is close to the bulk metal characteristics, resulting in low charge transfer efficiency when adsorbing gas molecules; second, conventional deposition techniques (such as inkjet printing and spin coating) make it difficult to construct a uniform and dense active layer within the submicron electrode gap, which can easily cause conductive channel breakage or excessive interface contact resistance; third, most nano-atomic cluster materials rely on other conductive materials to form devices, which makes the device manufacturing process complex and introduces additional noise sources and reduces sensing stability.
[0004] However, how to simply and cost-effectively achieve high-density integration of clusters in micro-nano devices while maintaining their catalytic activity and structural integrity, and ultimately realizing highly sensitive chemical gas sensors, remains a technical bottleneck. Existing methods are complex and have extremely high requirements for conductive channel materials and nano-atomic clusters. Summary of the Invention
[0005] The purpose of the present invention is to provide a chemical gas sensor chip based on metal atom clusters using dielectrophoresis technology to improve the detection limit of metal atom cluster-based sensors in the field of chemical gas detection.
[0006] The purpose of the present invention can be achieved through the following technical solutions:
[0007] A chemical gas sensor chip based on metal atom clusters using dielectrophoresis technology comprises, from the inside out, a silicon oxide substrate, an oxide layer, a metal electrode, and a metal atom cluster channel. The chemical gas sensor structure is prepared by the following steps:
[0008] An electron beam direct write exposure device is used to write the pattern of micro-nano metal electrodes 1 on the oxide layer, with gaps between the nano-metal electrodes 1. This pattern is then developed and a chromium alloy is deposited. Next, ultraviolet lithography is used to expose measurement electrodes (2, 3, 4) on the surface. A gap exists between the measurement electrodes on one side (i.e., the bias electrode 2 and the coupling electrode 3). This is then developed and vapor-deposited with a chromium alloy. Finally, the device structure is cleaned with acetone, ethanol, and deionized water, and dried.
[0009] Furthermore, the silicon substrate is a silicon oxide substrate or a silicon oxide wafer.
[0010] Furthermore, the thickness of the chromium alloy metal electrode is 55nm, wherein 5nm of chromium metal is first deposited at a deposition rate of Then 50nm of gold was deposited at a deposition rate of
[0011] Furthermore, the gap between the nanometal electrodes 1 is 50 nm, the electrode width is 50 nm, the gap between the measuring electrodes on one side (ie, the bias electrode 2 and the coupling electrode 3) is 2 μm, and the electrode width is 300 μm.
[0012] Furthermore, the chemical gas sensor chip based on metal atom clusters using dielectrophoresis technology is prepared by the following steps:
[0013] The metal atomic clusters are dispersed in the solution to form a metal atomic cluster solution with a concentration of 3.25mM. The atomic cluster solution is dripped into the area between the nanoelectrodes 1 using a pipette to cover the nanoelectrode 1. A high-frequency pulse voltage is applied between the bias electrode 2 and the counter electrode 4. After half an hour, the metal atomic clusters on the surface are cleaned off with ethylene glycol and ethanol respectively, and then blown dry with nitrogen to obtain a chemical gas sensor chip based on metal atomic clusters using dielectrophoresis technology.
[0014] Furthermore, the applied pulse high-frequency voltage has a frequency of 10 MHz and an amplitude of 1 V.
[0015] Beneficial effects of the present invention:
[0016] The device structure of the present invention has two capacitors. The first capacitor exists between the coupling electrode 3 and the counter electrode 4. Because the electrode pair area is small, the capacitance is small and the capacitive reactance is large. The second capacitor exists between the bias electrode 2 and the coupling electrode 3. Its electrode pair area is large, so the capacitance is relatively large and the capacitive reactance is small. When a high-frequency voltage is applied, a strong electric field is formed between the coupling electrode 3 and the counter electrode 4. The position where the electric field is strongest is the area where the electrode and the oxide layer contact. The metal atom clusters are arranged in an orderly manner under the action of the strong electric field and assembled between the two electrodes, and connected at the bottom to form a conductive channel with only two or three layers. This structure can be assembled into tens of thousands of sensor units on a large scale on a wafer, which plays an important role in improving the preparation rate of the device and reducing costs.
[0017] Metal clusters are recognized as highly efficient catalysts with excellent gas adsorption and desorption properties. Gas molecules can rapidly adsorb and react chemically on the surface of metal clusters, resulting in significant changes in the electrical signal, making them easier to detect. In the presence of gas, electron transfer occurs on the surface of the metal clusters, and the resulting resistance change can be precisely detected and used to quantify the gas concentration. With the assistance of dielectrophoresis, the metal clusters are orderly assembled in the channel without agglomeration, forming a relatively thin and dispersed nanoscale conductive channel, which increases the channel's conductivity. This structure significantly increases the specific surface area of the metal clusters, exposing more metal atoms and increasing the probability of contact with gas molecules. This structure not only improves the gas adsorption efficiency but also promotes the decomposition and reaction of gases on the metal cluster surface, further enhancing the sensitivity of the sensor. Specifically, the channel structure provides more reaction sites, allowing more gas molecules to interact with the metal clusters, resulting in a more significant resistance change, thus achieving highly sensitive detection. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention will be further described below with reference to the accompanying drawings.
[0019] Figure 1 1 is a structural diagram of a sample chemical gas sensor prepared in Example 1 of the present invention.
[0020] Figure 2 This is a graph showing the response of the platinum metal atomic cluster sensor prepared in Example 2 of the present invention to hydrogen of different concentrations. DETAILED DESCRIPTION
[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part 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 shall fall within the scope of protection of the present invention.
[0022] A gas sensor chip based on metal atom clusters using dielectrophoresis technology comprises, from the inside out, a silicon oxide substrate, an oxide layer, a metal electrode, and a metal atom cluster channel. The oxide layer is 300 nm thick.
[0023] Example 1
[0024] This embodiment provides a gas sensor structure, which is prepared by the following steps:
[0025] The silicon oxide substrate was cleaned with acetone, isopropyl alcohol and deionized water, and then 250nm PMMA electron beam glue was spin-coated on the silicon wafer surface. Nano-metal electrode patterns were written on the glue by electron beam exposure. After development, 5nm chromium metal was evaporated on the surface at a deposition rate of Then 50nm of gold was deposited at a deposition rate of After stripping, the measuring electrodes are exposed on the surface by UV lithography. A gap is left between the measuring electrodes on one side. Then, chromium alloy of the same thickness is deposited by development and evaporation. Finally, the device structure is obtained after cleaning with acetone, ethanol and deionized water and drying. Figure 1 shown.
[0026] Example 2
[0027] This embodiment provides a hydrogen sensor chip based on platinum metal atomic clusters using dielectrophoresis technology, which is prepared by the following steps:
[0028] Platinum metal clusters were dispersed into a solution to form a 3.25 mM metal cluster solution. This solution was then pipetted into the area between the nanoelectrodes, covering them. A high-frequency pulse voltage with a frequency of 10 MHz and an amplitude of 1 V was applied between the bias and counter electrodes. After half an hour, the surface platinum clusters were cleaned with ethylene glycol and ethanol, respectively, and dried with nitrogen, resulting in a hydrogen sensor chip based on platinum metal clusters using dielectrophoresis technology.
[0029] Performance test of Example 2:
[0030] The prepared sample is bonded to a chip carrier via aluminum wire. The chip carrier is then placed in a custom-made test base with a sealed chamber. The top of the test base has two air holes, one for admitting the test gas or background gas, and one for exhausting the gas. The test base is connected to a high-precision meter to monitor and capture changes in the electrical signal.
[0031] The test temperature is carried out at room temperature. Different concentrations (20-1000ppb) of the test gas (hydrogen) are introduced and the electrical signal is recorded. Each time hydrogen is introduced for 30 seconds, and then nitrogen is introduced for decomposition and recovery, and the time is also 30 seconds. Different concentrations are changed from low to high. Figure 2 shown.
[0032] The recorded results show that the hydrogen sensor prepared by the present invention can still maintain a high detection effect at extremely low hydrogen concentrations. The pink areas in the figure represent the time periods when different concentrations of hydrogen were introduced.
[0033] The time from the start to the point where the current reaches 10% of the response value is recorded as the response time. The results are shown in Table 1 below:
[0034] Table 1
[0035]
[0036]
[0037] The test results show that the hydrogen sensor structure prepared by the present invention has good sensitivity, low operating temperature requirement, and fast response time to different concentrations of hydrogen.
[0038] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.
[0039] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.
Claims
1. A chemical gas sensor chip based on metal atom clusters using dielectrophoresis technology, comprising, from the inside out, a silicon oxide substrate, an oxide layer, a metal electrode, and a metal atom cluster channel; characterized in that: The gas sensor chip is manufactured from an oxide sheet. The gas sensor structure is prepared by the following steps: using an electron beam direct writing exposure device to write a micro-nano metal electrode pattern on the oxide layer, with gaps between the micro-nano metal electrodes 1, then developing and depositing a chromium alloy, then using ultraviolet lithography to expose measuring electrodes (2, 3, 4) on the surface, with a gap between the measuring electrodes on one side (i.e., the bias electrode 2 and the coupling electrode 3), and then developing and evaporating a chromium alloy. Finally, the device structure is cleaned with acetone, ethanol, and deionized water, and dried. The chemical gas sensor chip based on metal atom clusters using dielectrophoresis technology is prepared by the following steps: The metal atomic clusters are dispersed in the solution to form a metal atomic cluster solution with a concentration of 3.25mM. The atomic cluster solution is dripped into the area between the nanoelectrodes 1 using a pipette to cover the nanoelectrode 1. A high-frequency pulse voltage is applied between the bias electrode 2 and the counter electrode 4. After half an hour, the metal atomic clusters on the surface are cleaned off with ethylene glycol and ethanol respectively, and then blown dry with nitrogen to obtain a chemical gas sensor chip based on metal atomic clusters using dielectrophoresis technology.
2. The chemical gas sensor chip based on metal atom clusters using dielectrophoresis technology according to claim 1, characterized in that: The substrate is a silicon oxide substrate or a silicon oxide wafer.
3. The chemical gas sensor chip based on metal atom clusters using dielectrophoresis technology according to claim 1, characterized in that: The metal atom clusters include but are not limited to gold, silver, platinum, palladium and the like.
4. The chemical gas sensor chip based on metal atom clusters using dielectrophoresis technology according to claim 1, characterized in that: The spacing between the chromium alloy micro-nano metal electrodes 1 is 50 nm, and the electrode width is 50 nm.
5. The chemical gas sensor chip based on metal atom clusters using dielectrophoresis technology according to claim 1, characterized in that: The gap between the nano bias electrode 2 and the coupling electrode 3 is 2 μm, and the electrode width is 300 μm.
6. The chemical gas sensor chip based on metal atom clusters using dielectrophoresis technology according to claim 1, characterized in that: The applied pulse high-frequency voltage has a frequency of 10 MHz and an amplitude of 1 V.