Compounds, gas sensors, and preparation methods for detecting DMMP

Abstract

This application discloses a compound for detecting DMMP, a gas sensor, and a preparation method. The compound has the structure shown in Formula 1, where R1, R2, and R3 each independently represent C1-C6 groups, and L1 and L2 each independently represent C1-C12 groups. The compound of this application can specifically bind to DMMP and can be firmly covalently bonded to a silicon substrate to construct a silicon-based gas sensor. After binding to DMMP, the compound generates an electrical response signal, enabling its application in silicon-based gas sensors to specifically identify DMMP. The gas sensor of this application generates an electrical response signal when in a DMMP gas atmosphere, exhibiting a detection limit as low as 556 ppb and a short response time of 13 seconds to a maximum of 110 seconds, meeting the requirements for rapid response, good reversibility, and demonstrating extremely high selectivity for DMMP.

Description

Technical Field

[0001] This application belongs to the field of gas sensor technology, specifically relating to a compound for detecting DMMP, a DMMP sensor, and a preparation method thereof. Background Technology

[0002] To prevent and respond to this invisible airborne poison gas, and to determine its range of influence, the development of gas detection technologies for nerve agents such as sarin is of great significance. Therefore, a large amount of research has focused on DMMP, a sarin simulant.

[0003] Traditional DMMP detection methods mainly include gas chromatography, ion mobility spectrometry, and infrared spectroscopy. These methods are widely used in laboratory environments due to their low detection limits and high accuracy. However, these traditional technologies also have many limitations, such as expensive and bulky equipment, complex operation, and the need for specialized technicians for maintenance and operation. Furthermore, the detection process is usually time-consuming, significantly reducing their applicability in mobile detection and rapid on-site analysis, especially failing to meet the real-time response requirements of single-point toxic gas early warning and wearable warning devices. In practical applications, these shortcomings severely limit the effectiveness of traditional detection technologies in dynamic and complex environments, making the development of portable sensors capable of achieving high selectivity and high sensitivity increasingly urgent. Summary of the Invention

[0004] The purpose of this application is to provide a compound for detecting DMMP, a DMMP sensor, and a preparation method to solve the technical problems of traditional DMMP detection methods, such as long detection time, low applicability in mobile detection and rapid on-site analysis, and difficulty in meeting the requirements of real-time response.

[0005] To achieve the above objectives, the first aspect of this application provides a compound for detecting DMMP, having the structure shown in general formula 1 below;

[0006] [General Formula 1]:

[0007] ;

[0008] In the general formula 1, R1, R2, and R3 each independently represent C1 to C6 groups, and L1 and L2 each independently represent C1 to C12 groups;

[0009] Wherein, the C1-C6 groups are straight-chain, branched, or cyclic groups, and the C1-C6 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C6 groups are optionally substituted with 0, 1, or more fluorine atoms; the C1-C12 groups are straight-chain, branched, or cyclic groups, and the C1-C12 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C12 groups are optionally substituted with 0, 1, or more fluorine atoms.

[0010] In one or more embodiments, the structure shown in general formula 2, general formula 3, general formula 4 or general formula 5 is provided;

[0011]

[0012]

[0013] R1, R2, and R3 each independently represent C1 to C6 groups.

[0014] In one or more embodiments, the C1-C6 groups are selected from methyl, ethyl, propyl, butyl, pentyl, or hexyl; and the C1-C12 groups are selected from methylene, ethylene, propylene, butylene, pentylene, hexylene, phenylene, tolylene, ethylphenylene, propylphenylene, pentylenephenylene, hexylene, fluorophenylene, biphenylene, or naphthylene.

[0015] In one or more embodiments, the C1-C6 groups are methyl groups.

[0016] In one or more embodiments, R1, R2, and R3 are all the same and represent methyl groups.

[0017] To achieve the above objectives, a second aspect of this application provides a method for preparing the compound described in any of the above embodiments, comprising:

[0018] The first reactant having the following general formula 6 and the second reactant having the following general formula 7 are dissolved in a solvent and stirred to react;

[0019] After the reaction is complete, the filtrate is collected by filtration and then post-processed to obtain the compound having general formula 1;

[0020]

[0021] In general formulas 6 and 7, A is selected from either an amino group or an isocyanate group, and when A is an amino group, B is an isocyanate group, and when A is an isocyanate group, B is an amino group.

[0022] R1, R2, and R3 each independently represent C1 to C6 groups, and L1 and L2 each independently represent C1 to C12 groups;

[0023] Wherein, the C1-C6 groups are straight-chain, branched, or cyclic groups, and the C1-C6 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C6 groups are optionally substituted with 0, 1, or more fluorine atoms; the C1-C12 groups are straight-chain, branched, or cyclic groups, and the C1-C12 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C12 groups are optionally substituted with 0, 1, or more fluorine atoms.

[0024] In one or more embodiments, the solvent is dichloromethane.

[0025] In one or more embodiments, the molar ratio of the first reactant to the second reactant is 1:(0.8~1.2).

[0026] In one or more embodiments, the stirring reaction takes 1 to 10 hours.

[0027] To achieve the above objectives, a third aspect of this application provides a gas sensor, comprising: a silicon substrate including a first surface and a second surface disposed opposite to each other; an insulating layer disposed on the first surface; a first silicon epitaxial layer and a second silicon epitaxial layer disposed at intervals on the surface of the insulating layer; a plurality of silicon nanoribbons disposed on the surface of the insulating layer, with their two ends respectively connected to the first silicon epitaxial layer and the second silicon epitaxial layer; a source electrode and a drain electrode disposed on the surface of the first silicon epitaxial layer and the surface of the second silicon epitaxial layer, respectively; and a gate electrode disposed on the second surface; wherein the first silicon epitaxial layer, the second silicon epitaxial layer, and the silicon nanoribbons have the same conductivity type;

[0028] The silicon nanoribbon surface is modified with the compound described above, wherein the R1, R2, and R3 groups of the compound are substituted so that the compound is covalently connected to the silicon nanoribbon.

[0029] In one or more embodiments, the compound is arranged in a monolayer on the surface of the silicon nanoribbon.

[0030] In one or more embodiments, the silicon nanoribbon has an extension length of 10-100 μm in the first direction, an extension width of 100 nm-10 μm in the second direction, and a thickness of 10-200 nm.

[0031] In one or more embodiments, the silicon nanoribbons extend along a first direction, and the plurality of silicon nanoribbons are uniformly spaced along a second direction; wherein, the first direction is the direction from the first silicon epitaxial layer to the second silicon epitaxial layer, and the second direction is perpendicular to the first direction.

[0032] To achieve the above objectives, a fourth aspect of this application provides a method for preparing a gas sensor according to any of the above embodiments, comprising:

[0033] A field-effect transistor (FET) is provided, comprising a silicon substrate, an insulating layer disposed on the surface of the silicon substrate, a first silicon epitaxial layer and a second silicon epitaxial layer disposed at intervals on the surface of the insulating layer, and a plurality of silicon nanoribbons disposed on the surface of the insulating layer and connected at both ends to the first silicon epitaxial layer and the second silicon epitaxial layer, respectively; the FET is subjected to hydroxylation treatment with a piranha solution comprising concentrated sulfuric acid and hydrogen peroxide to obtain a first silicon wafer; a source and a drain are fabricated on the first silicon wafer to obtain a second silicon wafer; a compound having general formula 1 is grafted onto the surface of the silicon nanoribbons of the second silicon wafer to obtain a third silicon wafer; a gate is fabricated on the third silicon wafer to obtain the gas sensor.

[0034] In one or more embodiments, the piranha solution is obtained by mixing 30% hydrogen peroxide and 98% concentrated sulfuric acid in a volume ratio of 3:(7~9).

[0035] In one or more embodiments, the hydroxylation treatment specifically involves: placing the field-effect transistor in a container, pouring the piranha solution into the container, heating a water bath, and then removing the field-effect transistor, cleaning, and drying; wherein the temperature of the water bath is 70~95 ℃ and the time is 10~60 min.

[0036] In one or more embodiments, the step of grafting a compound having general formula 1 onto the surface of silicon nanoribbons of the second silicon wafer includes: dissolving the compound in a solvent to obtain a modification solution; immersing the second silicon wafer in the modification solution, then removing it and drying it; wherein the concentration of the compound in the modification solution is 0.02~0.5 mol / L, and the immersion time is 0.5~5 h.

[0037] In one or more embodiments, prior to the step of fabricating the gate on the third silicon wafer, the method further includes: immersing the third silicon wafer in water, then removing it and drying it; wherein the immersion time is 3 to 10 hours.

[0038] The advantages of this application, which differ from existing technologies, are:

[0039] The compound of this application can specifically bind to DMMP and can be firmly bonded to a silicon substrate by covalent bonds to construct a silicon-based gas sensor. After binding to DMMP, the compound can generate an electrical response signal, so that the compound can be applied to silicon-based gas sensors to give them the ability to specifically recognize DMMP.

[0040] The gas sensor of this application can generate an electrical response signal when in a DMMP gas atmosphere. It has a short response time and can quickly achieve effective gas detection of DMMP. The gas sensor of this application embodiment can achieve a considerable response to 1-100 ppm DMMP and has a minimum detection limit as low as 556 ppb. The gas sensor of this application embodiment exhibits the characteristic that the response time decreases as the concentration increases, and has a short response time of 110 s at the longest and 13 s at the shortest, which can meet the requirements of rapid response.

[0041] The gas sensor of this application embodiment can completely recover its current value to the initial value in less than 230 seconds after returning to the air environment, indicating its good reversibility; the gas sensor of this application exhibits high selectivity for DMMP; the fabrication process of the gas sensor of this application is highly compatible with the chip fabrication process, providing a new approach for chip-level sarin gas sensors. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0043] Figure 1 This is a schematic flowchart of one embodiment of the method for preparing the compound used to detect DMMP in this application; Figure 2 This is a schematic diagram of the structure of one embodiment of the gas sensor of this application; Figure 3 This is a schematic diagram of the hydrogen bonding interaction between the gas sensor of this application and DMMP molecules; Figure 4 This is a schematic diagram illustrating the principle of one embodiment of the gas sensor of this application; Figure 5 This is a schematic flowchart of one embodiment of the gas sensor fabrication method of this application; Figure 6 This is a flowchart illustrating the fabrication process of one embodiment of the field-effect transistor of this application; Figure 7 yes Figure 5 A flowchart illustrating one embodiment corresponding to S40; Figure 8 This is the hydrogen NMR spectrum of Example 1 of this application; Figure 9 This is the surface chemical composition analysis spectrum of silicon nanoribbons in Example 2 of this application; Figure 10 This is the experimental data graph in Example 3 of the effect of this application; Figure 11 This is a photograph of the customized gas testing platform used in Example 3 of this application; Figure 12 This is a dynamic response diagram of the sensors in Example 1 and Comparative Example 3 of this application to 80 ppm DMMP; Figure 13 This is the dynamic response data of the sensor in Example 1 of Example 4 of this application to different concentrations of DMMP; Figure 14These are the device response data of the sensor in Example 1 of Example 4 of this application at different DMMP concentrations; Figure 15 This is the response-recovery cycle curve of the sensor in Example 1 of Example 4 of this application to 10 ppm DMMP; Figure 16 This is a graph showing the response data of the sensor in Example 1 of Example 5 of this application to 100 ppm DMMP, various VOCs and water; Figure 17 This is the current-voltage characteristic curve in Example 5 of this application. Detailed Implementation

[0044] To address the problems of traditional DMMP detection methods, the applicant has developed a compound that specifically binds to DMMP, exhibiting high selectivity and high sensitivity. This compound can be applied to DMMP detection, enabling real-time response to DMMP concentration.

[0045] Specifically, the compound has the structure shown in general formula 1;

[0046] [General Formula 1]:

[0047] ;

[0048] In general formula 1, R1, R2, and R3 each independently represent C1 to C6 groups; L1 and L2 each independently represent C1 to C12 groups.

[0049] Wherein, the C1-C6 groups are straight-chain, branched, or cyclic groups, and the C1-C6 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C6 groups are optionally substituted with 0, 1, or more fluorine atoms; the C1-C12 groups are straight-chain, branched, or cyclic groups, and the C1-C12 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C12 groups are optionally substituted with 0, 1, or more fluorine atoms.

[0050] The above compound has a hexafluoroisopropanol (HFIP) group at its end. DMMP is a hydrogen-bonded basic molecule that tends to form hydrogen bonds with hydrogen-bonded acidic molecules. The strong electronegativity of the fluorine atom in the HFIP group maximizes the hydrogen-bonding acidity of the hydroxyl group, enhancing the ability of the hydroxyl group in the HFIP group to form hydrogen bonds with DMMP. Therefore, this compound can form a DMMP-specific structure.

[0051] Meanwhile, the fluorine atoms in HFIP maximize the hydrogen bond acidity of the hydroxyl group and minimize the hydrogen bond basicity of the hydroxyl oxygen atom through the electron attraction effect, thereby effectively inhibiting the self-aggregation of HFIP groups.

[0052] In addition, the compounds shown in Formula 1 above have three binding sites at the positions of groups R1, R2, and R3, which can be covalently bonded to the silicon substrate to construct a silicon-based gas sensor. After the compound binds to DMMP, it can generate an electrical response signal, which enables the silicon-based gas sensor to specifically identify DMMP.

[0053] Of course, the compound of general formula 1 can also be incorporated into the mass sensor. After the compound adsorbs DMMP, it produces a mass change, which enables the mass sensor to specifically identify DMMP.

[0054] More specifically, in one embodiment, the compound may have the structure shown in general formula 2, in which R1, R2, and R3 each independently represent C1 to C6 groups.

[0055] In another embodiment, the L1 group in the above general formula 1 can be phenyl and the L2 group can be propylidene, so that the compound can have the structure shown in the following general formula 3; in general formula 3, R1, R2, and R3 each independently represent C1 to C6 groups.

[0056] In another embodiment, the L1 group in the above general formula 1 can be methylene and the L2 group can be phenylene, so that the compound can have the structure shown in the following general formula 4; in general formula 4, R1, R2, and R3 each independently represent C1 to C6 groups.

[0057] In another embodiment, the L1 group in the above general formula 1 can be phenylene and the L2 group can be methylene, so that the compound can have the structure shown in the following general formula 5; in general formula 5, R1, R2, and R3 each independently represent C1 to C6 groups.

[0058]

[0059]

[0060] This application also provides a method for preparing the above-mentioned compound; please refer to [link to method]. Figure 1 , Figure 1 This is a schematic flowchart of one embodiment of the method for preparing the compound used in the detection of DMMP according to this application.

[0061] like Figure 1 As shown, the preparation method includes:

[0062] S100. Dissolve the first reactant having general formula 6 and the second reactant having general formula 7 in a solvent and stir to react.

[0063] S200. After the reaction is complete, filter and collect the filtrate, and then process it to obtain a compound with general formula 1.

[0064]

[0065] In general formulas 6 and 7, A is selected from either an amino group or an isocyanate group, and when A is an amino group, B is an isocyanate group, and when A is an isocyanate group, B is an amino group.

[0066] In one embodiment, the solvent can be dichloromethane. In one embodiment, the molar ratio of the first reactant to the second reactant can be 1:1. In one embodiment, the stirring time can be 5 h. In one embodiment, the above-mentioned extraction, washing, and drying steps can specifically be as follows: extracting the filtrate with dichloromethane, then washing with water, collecting the organic phase, and then drying with anhydrous sodium sulfate.

[0067] In one embodiment, the above purification may specifically involve purifying the concentrated crude product by column chromatography (dichloromethane:ethyl acetate = 4:1, v:v).

[0068] Specifically, the reaction formula for the above preparation method can be one of the following formulas:

[0069] ;

[0070] .

[0071] This application also provides a gas sensor based on the above-mentioned compound, specifically a silicon nanoribbon field-effect transistor (SiNW FET) gas sensor, which is capable of high sensitivity and high selectivity detection of DMMP.

[0072] Specifically, please refer to Figure 2 , Figure 2 This is a schematic diagram of one embodiment of the gas sensor of this application.

[0073] like Figure 2 As shown, the sensor includes a silicon substrate 100, which has a first surface and a second surface disposed opposite to each other. An insulating layer 200 is disposed on the first surface, and a first silicon epitaxial layer 300 and a second silicon epitaxial layer 400 disposed on the insulating layer 200 at intervals.

[0074] Multiple silicon nanoribbons 500 are also arranged on the insulating layer 200, and the two ends of the multiple silicon nanoribbons 500 are respectively connected to the first silicon epitaxial layer 300 and the second silicon epitaxial layer 400.

[0075] A source electrode 600 and a drain electrode 700 are respectively arranged on the first silicon epitaxial layer 300 and the second silicon epitaxial layer 400, and a gate electrode 800 is arranged on the second surface.

[0076] In one embodiment, the silicon substrate 100 may be an intrinsic silicon substrate 100, and the insulating layer 200 may be a silicon dioxide insulating layer 200.

[0077] The first silicon epitaxial layer 300, the second silicon epitaxial layer 400, and the silicon nanoribbon 500 have the same conductivity type. For example, the first silicon epitaxial layer 300, the second silicon epitaxial layer 400, and the silicon nanoribbon 500 can be p-type semiconductor layers doped with a first conductivity type dopant, such as Mg, Zn, Ca, Sr, and Ba; or they can be n-type semiconductor layers doped with a second conductivity type dopant, such as Si, Ge, Sn, Se, and Te.

[0078] The surface of the silicon nanoribbon 500 is modified with the compound of any of the above embodiments. During the modification process, the R1, R2, and R3 groups of the compound are replaced so that the compound is covalently connected to the silicon nanoribbon.

[0079] Specifically, the connection structure between the silicon nanoribbons 500 and the above-mentioned compound can be as follows:

[0080]

[0081] In a preferred embodiment, the compound can adopt the structure shown in general formula 2, and the connection structure between the silicon nanoribbon 500 and the above compound can be as follows: .

[0082] Please see Figure 3 , Figure 3 This is a schematic diagram of the hydrogen bonding interaction between the gas sensor of this application and DMMP molecules. When the gas sensor of the above embodiments is in a DMMP gas atmosphere, the hydroxyl groups of the HFIP group can form hydrogen bonds with DMMP molecules, resulting in specific physical adsorption of DMMP molecules.

[0083] Because the phosphorus-oxygen double bond (P=O) in the DMMP molecule is highly polar and exhibits electron-withdrawing properties, it reduces the number of electrons in the silicon nanoribbon, increases the hole concentration, and thus affects the conductivity, generating an electrical response signal.

[0084] Specifically, please refer to Figure 4 , Figure 4 This is a schematic diagram illustrating the principle of one embodiment of the gas sensor of this application, as shown below. Figure 4As shown, when the silicon nanoribbon 500 is a p-type semiconductor, after surface modification with a compound of general formula 1, the HFIP group exhibits strong electron-withdrawing properties. This property reduces the number of minority electrons in the p-type silicon nanoribbon and increases the concentration of majority holes, thereby improving the conductivity of the silicon nanoribbon 500 and enhancing its current transmission performance. Furthermore, when exposed to a DMMP gas atmosphere and combined with DMMP, the phosphorus-oxygen double bond (P=O) in the DMMP molecule has strong polarity and exhibits electron-withdrawing properties, further increasing the hole concentration in the silicon nanoribbon and improving the conductivity, thereby generating an electrical signal with increased current.

[0085] Of course, in another embodiment, when the silicon nanowire 500 is an n-type semiconductor, its charge carriers are electrons. When exposed to a DMMP gas atmosphere and combined with DMMP, the electron concentration in the silicon nanowire 500 will be reduced due to the electron-withdrawing properties of DMMP, thereby reducing the conductivity and generating an electrical signal with reduced current.

[0086] Preferably, the first silicon epitaxial layer 300, the second silicon epitaxial layer 400, and the silicon nanoribbon 500 can all be p-type silicon, thereby improving the test sensitivity.

[0087] The above embodiments utilize silicon nanoribbon field-effect transistors to achieve effective gas detection of DMMP. The device exhibits good repeatability and selectivity, achieving excellent sensing performance for DMMP. At the same time, the device has the advantages of convenient fabrication and compatibility with modern chip manufacturing processes, laying the foundation for realizing chip-level integrated DMMP gas sensors.

[0088] It should be noted that this application only discloses a silicon nanoribbon field-effect transistor sensor using the above-mentioned compound. This compound can also be applied to other sensors, such as other types of silicon-based electrical signal sensors, or silicon-based mass sensors, etc., and can also achieve specific detection of DMMP. It is understood that the detection sensitivity of different sensors may vary.

[0089] This application also provides a method for manufacturing a gas sensor according to any of the above embodiments. Please refer to [link to relevant documentation]. Figure 5 , Figure 5 This is a schematic flowchart of one embodiment of the gas sensor fabrication method of this application.

[0090] like Figure 5 As shown, the preparation method includes:

[0091] S10 provides a field-effect transistor.

[0092] The field-effect transistor includes a silicon substrate, an insulating layer disposed on the surface of the silicon substrate, a first silicon epitaxial layer and a second silicon epitaxial layer disposed at intervals on the surface of the insulating layer, and a plurality of silicon nanoribbons disposed on the surface of the insulating layer and connected at both ends to the first silicon epitaxial layer and the second silicon epitaxial layer, respectively.

[0093] In one embodiment, the field-effect transistor can be fabricated using SOI wafers as raw materials and a top-down method. (See [link to relevant documentation]). Figure 6 , Figure 6 This is a flowchart illustrating the fabrication process of one embodiment of the field-effect transistor of this application.

[0094] like Figure 6 As shown, an SOI wafer may include a silicon substrate layer, a silicon oxide insulating layer and a p-type silicon layer stacked sequentially from bottom to top. By performing photolithography and etching processes sequentially on the surface of the p-type silicon layer, the p-type silicon layer can be etched to obtain a first silicon epitaxial layer, a second silicon epitaxial layer and silicon nanoribbons.

[0095] Of course, in other embodiments, a silicon substrate can be used as the raw material, and an insulating layer and a p-type silicon layer can be grown sequentially on the silicon substrate. Then, the p-type silicon layer can be subjected to photolithography and etching processes to obtain a field-effect transistor.

[0096] The aforementioned photolithography and etching processes are well known to those skilled in the art and will not be described in detail here.

[0097] S20. The field-effect transistor is hydroxylated using a piranha solution to obtain the first silicon wafer.

[0098] In order for the compound to be covalently bonded to the silicon nanoribbon, the field-effect transistor needs to be hydroxylated first so that hydroxyl groups are formed on the surface of the silicon nanoribbon.

[0099] Specifically, the field-effect transistor can be hydroxylated using a piranha solution, which is obtained by mixing 30% hydrogen peroxide and 98% concentrated sulfuric acid in a volume ratio of 3:(7~9).

[0100] In one embodiment, the hydroxylation treatment specifically involves: placing the field-effect transistor (FET) in a container, pouring a piranha solution into the container, heating it in a water bath, then removing the FET, cleaning it, and drying it; wherein the water bath temperature can be 70~95 °C, and the time can be 10~60 min. Preferably, the water bath temperature can be 90 °C, and the time can be 30 min.

[0101] It should be noted that during the hydroxylation process, the silicon wafer should be placed in a beaker first, and then the piranha solution should be poured in slowly to prevent the generation of too many bubbles, which could affect subsequent processing.

[0102] To avoid damage to the electrode caused by hydroxylation treatment, the hydroxylation treatment step is placed before electrode preparation in this embodiment.

[0103] S30. The source and drain electrodes are fabricated on the first silicon wafer to obtain the second silicon wafer.

[0104] Specifically, a metal mask can be used to cover the surface of the first silicon wafer, and then metal electrodes can be prepared by metal evaporation on the surfaces of the first and second silicon epitaxial layers.

[0105] S40. A compound having general formula 1 is grafted onto the surface of a silicon nanoribbon to obtain a third silicon wafer.

[0106] After the metal electrode is prepared, compounds can be further grafted onto the surface of the silicon nanoribbon.

[0107] In one implementation, please refer to Figure 7 , Figure 7 yes Figure 5 A flowchart of one embodiment corresponding to S40.

[0108] like Figure 7 As shown, a method for grafting a compound having general formula 1 onto the surface of a silicon nanoribbon may include:

[0109] S401. Dissolve the compound in a solvent to obtain a modified solution.

[0110] S402. Immerse the second silicon wafer in the modification solution, then remove it and dry it.

[0111] In one embodiment, the concentration of the compound in the modification solution can be 0.02~0.5 mol / L, and the soaking time can be 0.5~5 h. Preferably, the concentration of the compound in the modification solution is 0.085 mol / L, and the soaking time is 2 h.

[0112] In one embodiment, the solvent may be ethanol.

[0113] Based on this step, the R1, R2, and R3 groups of the compound having general formula 1 can react with the hydroxyl groups on the surface of silicon nanoribbons, thereby enabling the compound to be covalently linked to the silicon nanoribbons.

[0114] S50. Immerse the third silicon wafer in water, then remove it and dry it.

[0115] Furthermore, in order to ensure that the compounds with general formula 1 can be arranged in a monolayer on the surface of silicon nanoribbons, thereby ensuring the detection sensitivity of the sensor, in this embodiment, the third silicon wafer is immersed in water to remove compounds that are not directly covalently bonded to silicon.

[0116] In one embodiment, the soaking time can be 3 to 10 hours. Preferably, the soaking time can be 6 hours.

[0117] S60. A gate is fabricated on the third silicon wafer to obtain a gas sensor.

[0118] After the compound grafting is completed, a gate can be fabricated on the back side of the silicon substrate. The gate can be fabricated by bonding a metal thin film or by metal evaporation, both of which can achieve the effect of this embodiment.

[0119] The effects of the technical solution of this application will be further explained in detail below with reference to specific embodiments.

[0120] Example 1:

[0121] A silicon nanoribbon field-effect transistor gas sensor, with the structure as follows: Figure 2 As shown, the silicon nanoribbons are surface-modified with a single layer of compound, and the connection structure is as follows: ;

[0122] The sensor was prepared using the following steps:

[0123] Step (1): Using SOI wafers as raw materials, the top silicon layer of the SOI wafer is p-type with a doping concentration of 10. 15 cm -3 The resistivity is 1~10 Ω·cm and the thickness is 140 nm; the silicon substrate thickness is 450 μm and the buried silicon oxide thickness is 450 nm. The SOI wafer is cut into 2 cm square pieces, then immersed in ultrasonic cleaning, photolithography and etching are performed to etch the top silicon layer to obtain the first silicon epitaxial layer, the second silicon epitaxial layer and 20 silicon nanoribbons located between the two. The length of the silicon nanoribbons is 50 μm and the width is 2 μm, thus obtaining the first silicon wafer;

[0124] Step (2): After cleaning the first silicon wafer, place it in a beaker, heat the piranha washing solution (30% hydrogen peroxide and 98% concentrated sulfuric acid, volume ratio 1:3), and perform hydroxylation in a water bath at 90 ℃ for 30 min. Then take it out and rinse it clean to obtain the second silicon wafer.

[0125] Step (3): The metal mask is attached to the surface of the second silicon wafer, and the source and gate are prepared by metal evaporation.

[0126] Step (4): Add (3-propyl isocyanate)trimethoxysilane (0.8 g, 3.9 mmol), 4-(hexafluoro-2-hydroxyisopropyl)aniline (1 g, 3.9 mmol), and dichloromethane (50 mL) to a 100 mL round-bottom flask. After sonication to dissolve, stir at room temperature for 5 h. After the reaction is complete, filter out the precipitate and extract the filtrate with dichloromethane (100 mL × 3), then wash with water (300 mL × 3). Collect the organic phase and dry it with anhydrous sodium sulfate. After filtration and concentration, the crude product is purified by column chromatography (dichloromethane:ethyl acetate = 4:1, v:v) to obtain 590 mg of white powder.

[0127] Dissolve 86.1 mg of the product in 2 ml of ethanol to prepare an ethanol solution with a concentration of 0.085 mol / L as a modification solution; immerse the second silicon wafer in the modification solution, soak for 2 h, remove it, rinse with deionized water, and dry in a drying oven at 120 ℃ for 2 h to obtain the third silicon wafer.

[0128] Step (5): The third silicon wafer is immersed in deionized water for 6 hours to hydrolyze it in order to remove molecules on the surface that are not directly covalently bonded to silicon, and then dried with nitrogen gas.

[0129] Step (6): An indium gallium alloy layer is attached to the back of the silicon substrate to prepare the gate.

[0130] Example 2:

[0131] A silicon nanoribbon field-effect transistor gas sensor, with the structure as follows: Figure 2 As shown, the silicon nanoribbons are surface-modified with a single layer of compound, and the connection structure is as follows:

[0132] ;

[0133] The preparation method of this sensor is basically the same as that in Example 1, except that:

[0134] In step (4), 3.9 mmol of isocyanate-based methyltrimethoxysilane and 3.9 mmol of The reaction was carried out to obtain the product, and then the product was dissolved in ethanol to prepare an ethanol solution with a product concentration of 0.085 mol / L as a modification solution.

[0135] Example 3:

[0136] A silicon nanoribbon field-effect transistor gas sensor, with the structure as follows: Figure 2 As shown, the silicon nanoribbons are surface-modified with a single layer of compound, and the connection structure is as follows:

[0137] ;

[0138] The preparation method of this sensor is basically the same as that in Example 1, except that:

[0139] In step (4), 3.9 mmol of aminomethyltrimethoxysilane and 3.9 mmol of The reaction was carried out to obtain the product, which was then dissolved in ethanol to prepare an ethanol solution with a product concentration of 0.085 mol / L as a modification solution.

[0140] Example 4:

[0141] A silicon nanoribbon field-effect transistor gas sensor, with the structure as follows: Figure 2 As shown, the silicon nanoribbons are surface-modified with a single layer of compound, and the connection structure is as follows:

[0142] ;

[0143] The preparation method of this sensor is basically the same as that in Example 1, except that:

[0144] In step (4), 3.9 mmol of 1-isocyanate-4-(trimethoxysilyl)benzene and 3.9 mmol of The reaction was carried out to obtain the product, and then the product was dissolved in ethanol to prepare an ethanol solution with a product concentration of 0.085 mol / L as a modification solution.

[0145] Comparative Examples 1 and 2:

[0146] A silicon nanoribbon field-effect transistor gas sensor is prepared using a method basically the same as in Example 1, except that:

[0147] In the preparation method of Comparative Example 1, step (2) is omitted, while in step (2) of Comparative Example 2, the water bath temperature is 25°C.

[0148] Comparative Example 3:

[0149] A silicon nanoribbon field-effect transistor gas sensor is prepared using a method basically the same as in Example 1, except that:

[0150] No steps (2), (4), (5).

[0151] Example of effect 1:

[0152] The white powder product obtained in step 4 of Example 1 was subjected to 1H NMR spectroscopy. Its chemical shift and coupling were tested by dissolving it in deuterated dimethyl sulfoxide (DMSO-d6) solvent. Figure 8 , Figure 8 This is the hydrogen NMR spectrum of Example 1 of this application.

[0153] like Figure 8 As shown, hydrogen atom peaks from the urea group appeared at δ 8.65 and δ 8.48 ppm, hydrogen atom peaks from the benzene ring appeared at δ 7.49 ppm, and hydrogen atom peaks from the carbon-oxygen single bond appeared at δ 6.18 ppm. These 1H NMR spectroscopy results are consistent with the expected molecular structure, and the urea group peaks, in particular, indicate the successful conduct of the isocyanate-amine reaction. These results demonstrate that the target molecule was successfully synthesized.

[0154] Example 2:

[0155] XPS analysis was performed on the surface chemical composition of the silicon nanoribbons of the sensor prepared in Example 1, and the results were obtained. Figure 9 , Figure 9 The image shows the surface chemical composition analysis spectrum of the silicon nanoribbon in Example 2 of this application, where a is the XPS full spectrum, b is the C 1s elemental spectrum and peak fitting results, and c is the F 1s elemental spectrum and peak fitting results.

[0156] like Figure 9 As shown in Figure a, untreated silicon nanoribbons contain three elements: Si, C, and O. In addition to the aforementioned three elements, HFIP-modified silicon nanoribbons also show two elements: F and N, which is consistent with the elements of the modified molecule.

[0157] like Figure 9 As shown in Figures b and c, a fine fitting of the elemental peaks for carbon and fluorine reveals a distinct urea group (-NH-CO-NH-) peak at 288.5 eV, a trifluoromethyl peak from the HFIP group at 292.7 eV, and a peak representing the -C-OH portion of the HFIP group at 286.3 eV. A distinct trifluoromethyl peak is also present in the fluorine elemental spectrum.

[0158] The full spectrum and elemental spectrum of XPS above both indicate that the hexafluoroisopropanol group was successfully modified on the surface of the silicon nanoribbon.

[0159] Example of effect 3:

[0160] Using the second silicon wafer prepared in step (2) of Example 1 and Comparative Examples 1 to 2 as samples, the water contact angle on the surface of the second silicon wafer was measured to obtain... Figure 10 , Figure 10 These are experimental data graphs from Example 3 of this application, where a is the water contact angle image of Comparative Example 1, b is the water contact angle image of Comparative Example 2, c is the water contact angle image of Example 1, and d is a statistical graph of water contact angle.

[0161] like Figure 10As shown, the surface of the second silicon wafer in Comparative Example 1 that has not undergone hydroxylation treatment has a water contact angle of approximately 55°, and this surface contains a certain amount of hydroxyl groups provided by the native oxide layer.

[0162] In Comparative Example 2, after being soaked in a piranha solution at 25 °C for 30 minutes, the water contact angle on the surface of the second silicon wafer decreased to about 45°, and the hydroxyl density increased.

[0163] In Example 1, after immersion in a piranha solution at 90 °C for 30 min, the water contact angle on the surface of the second silicon wafer further decreased to approximately 14°, and the hydroxyl density significantly increased. These results indicate that the hydroxylation process employed in Example 1 has a significant effect on improving the surface hydroxyl density.

[0164] Example of effect 4:

[0165] use Figure 11 The customized gas testing platform shown was used for gas-sensing performance testing. Figure 11 These are photographs of the customized gas testing platform used in Example 4 of this application, where a is a top view of the testing platform with the lid open; and b is a side view of the testing platform with the lid closed.

[0166] This custom gas testing platform includes a sample stage and a heating stage located in a sealed chamber with a fixed volume. The desired DMMP gas concentration atmosphere is created by adding a certain amount of DMMP liquid to the heating stage and accelerating the evaporation of the liquid through the heating stage.

[0167] Specifically, the performance parameters tested include responsivity, minimum detection limit, response time, recovery time, repeatability, and selectivity. The electrical signal responsivity is calculated using the following formula:

[0168]

[0169] Response time and recovery time are calculated as the time required to reach 90% of the maximum responsiveness and the time required for the responsiveness to decrease to 90%, respectively.

[0170] First, the sensors from Example 1 and Comparative Example 3 were placed on the sample stage, respectively. DMMP liquid was then delivered to the heated platform using a microsyringe, and their electrical response to 80 ppm DMMP was tested. Figure 12 , Figure 12 This is a dynamic response diagram of the sensor in Example 1 and Comparative Example 3 of this application to 80 ppm DMMP (the light background in the figure is the air atmosphere, and the dark background is the DMMP atmosphere).

[0171] like Figure 12As shown, the unmodified silicon nanoribbons in Comparative Example 3 exhibited the chemical inertness of silicon itself and showed no response signal to 80 ppm DMMP. In contrast, the surface-functionalized silicon nanoribbons in Example 1 showed significant response-recovery performance to DMMP, displaying a typical response-recovery curve of the device to 80 ppm DMMP.

[0172] HFIP-modified silicon nanoribbons exhibit a 45% response to 80 ppm DMMP. Furthermore, they are able to recover to their initial state after a period of time, demonstrating good reversibility.

[0173] Furthermore, the sensor from Example 1 was placed on the sample stage, and DMMP liquid was delivered to the heating platform using a microsyringe. Its electrical response to different concentrations of DMMP was tested, and the results were obtained. Figure 13 , Figure 13 The following are the dynamic response data of the sensor in Example 1 of this application to different concentrations of DMMP. Among them, a is the dynamic response-recovery curve of the sensor in Example 1 to 1-100 ppm DMMP (the light background in the figure is the air atmosphere, and the dark background is the DMMP atmosphere, and its concentration is marked in the figure in ppm), b is the dot plot of the response of the sensor in Example 1 to 1-100 ppm DMMP, and c is the fitting curve of the response of the sensor in Example 1 to 1-15 ppm DMMP.

[0174] like Figure 13 As shown in Figure a, within the concentration range of 100 ppm to 1 ppm, the sensor of Example 1 exhibited good response and recovery performance for both higher and lower concentrations of DMMP.

[0175] Furthermore, the applicant calculated the response values ​​of the sensor in Example 1 at various concentrations and displayed them in the form of a dot plot, as shown below. Figure 13 As shown in Figure b, the response value is not linearly related to the concentration in the wide range of 1 ppm to 100 ppm. Instead, it shows a trend of gradually decreasing response value increment as the concentration increases. This is mainly attributed to the fact that at high concentrations, most adsorption sites are occupied, and the number of effective sites that can improve the response value decreases.

[0176] Furthermore, the applicant performed linear fitting on the response values ​​of the five lowest concentration points to determine the lowest detection limit for DMMP, such as... Figure 13 As shown in Figure c, below a concentration of 15 ppm, there is an approximately linear relationship between the concentration and the response value. By extrapolating the functional relationship between the response sensitivity and the DMMP concentration through the linear relationship, the theoretical detection limit of the sensor in Example 1 for DMMP is approximately 556 ppb.

[0177] Response time of gas sensor (T)res ) and recovery time (T) rec The response time and recovery time of the sensor in Example 1 to different concentrations of DMMP are important indicators for evaluating sensor performance, typically used to assess its response speed to gas changes and its ability to recover to a baseline state. Therefore, the applicant further calculated the response time and recovery time of the sensor in Example 1 to different concentrations of DMMP, obtaining... Figure 14 , Figure 14 These are the device response data of the sensor in Example 1 of Example 4 of this application under different DMMP concentrations, where a is the device response time under different DMMP concentrations and b is the device recovery time under different DMMP concentrations.

[0178] like Figure 14 As shown in Figure a, at high concentrations (60-100 ppm), the device response time is relatively short, all below 15 s; however, starting from 40 ppm, the response time increases significantly as the concentration decreases further, reaching a maximum of 110 s. This phenomenon can be attributed to the lower probability of DMMP adsorption at the active sites on the silicon nanoribbon surface at lower concentrations, thus increasing the response time accordingly. In summary, the device response time is between 13-110 s, with higher concentrations resulting in shorter response times, indicating a faster response speed.

[0179] like Figure 14 As shown in Figure b, the recovery time initially increases and then decreases with increasing concentration, with the shortest recovery time being 76 s and the longest being 230 s. This phenomenon can be attributed to the fact that at low concentrations, due to the smaller adsorption amount, desorption is faster and the recovery time is shorter. However, at high concentrations, when the DMMP concentration reaches a certain level, most of the effective adsorption sites are occupied. As the concentration further increases, more DMMP molecules are attached to the silicon nanoribbon surface in a less stable state. These molecules rapidly detach when the environment is changed to air. Since the recovery time calculation is not based on complete desorption, the rapid desorption of these unstable connections shortens the time to reach 90% total desorption.

[0180] Furthermore, the sensors from Examples 2 to 4 were placed on the sample stage, and DMMP liquid was delivered to the heating platform using a microsyringe. Their electrical response to 80 ppm DMMP was tested, and the data in the table below were obtained.

[0181]

[0182] As shown in the table above, the gas sensor obtained by molecularly modifying the surface of a silicon nanoribbon field-effect transistor using the design of this application can effectively detect DMMP gas. When in contact with DMMP gas, the current signal increases significantly, and the response time is on the order of tens of seconds, enabling timely and rapid detection of DMMP gas.

[0183] To verify the repeatability of the sensor, the applicant conducted five consecutive cycles of testing on the sensor of Example 1 at a concentration of 10 ppm DMMP, and obtained the results. Figure 15 , Figure 15 This is the response-recovery cycle curve of the sensor in Example 1 of Example 4 of this application to 10 ppm DMMP.

[0184] like Figure 15 As shown in the figure, in five consecutive tests, the current values ​​in a 10 ppm DMMP atmosphere were 0.556 μA, 0.555 μA, 0.548 μA, 0.558 μA, and 0.549 μA, respectively, with minimal differences between the five results. Furthermore, the response and recovery curves are quite consistent across the five cycles, with similarly small differences in response and recovery times. The device exhibits good consistency with the same DMMP concentration, indicating its stable operation.

[0185] To verify the selectivity of the sensor, the response of the sensor in Example 1 to ethanol, methanol, dichloromethane, acetone, isopropanol, water, and DMMP was tested, and the results were obtained. Figure 16 , Figure 16 This is a graph showing the response data of the sensor in Example 1 of Example 5 of this application to 100 ppm DMMP, various VOCs and water.

[0186] like Figure 16 As shown, thanks to the chemical inertness of silicon and the excellent selectivity of the HFIP group for DMMP molecules, the device exhibits extremely low responsiveness to volatile organic compounds other than DMMP, demonstrating high selectivity for DMMP gas. Furthermore, the device's complete lack of response to water indicates its insensitivity to humidity, enabling it to operate under varying humidity conditions.

[0187] To investigate the sensor's response mechanism to DMMP, the applicant conducted electrical performance tests on the unmodified bare silicon nanoribbon in Comparative Example 3, the silicon nanoribbon of Example 1 placed in an air atmosphere, and the silicon nanoribbon of Example 1 placed in a DMMP atmosphere. The source-drain voltage was varied in 0.5 V steps between -10 V and 10 V to measure the relationship between the drain current and the source-drain voltage. Figure 17 , Figure 17 This is the current-voltage characteristic curve in Example 5 of this application.

[0188] like Figure 17 As shown, under the same voltage, the current of bare silicon nanoribbons gradually increases after surface modification and further adsorption of DMMP molecules, which is consistent with... Figure 4Matching the principles shown, when silicon nanoribbons are p-type semiconductors, after surface modification of silicon nanoribbons, the HFIP groups at the ends of the modified molecules exhibit strong electron-withdrawing properties. This property reduces the number of minority electrons in p-type silicon nanoribbons and increases the concentration of majority holes, thereby improving the conductivity of silicon nanoribbons and enhancing current transport performance. When exposed to a DMMP atmosphere, due to the strong polarity of the phosphorus-oxygen double bond (P=O) in DMMP molecules, it exhibits electron-withdrawing properties, further increasing the hole concentration in silicon nanoribbons and improving conductivity.

[0189] It will be apparent to those skilled in the art that this application is not limited to the details of the exemplary embodiments described above, and that this application can be implemented in other specific forms without departing from the spirit or essential characteristics of this application. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this application is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this application. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0190] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A compound for detecting DMMP, characterized in that, It has the structure shown in the following general formula 1; [General Formula 1]: ； In the general formula 1, R1, R2, and R3 each independently represent C1 to C6 groups, and L1 and L2 each independently represent C1 to C12 groups; Wherein, the C1-C6 groups are straight-chain, branched, or cyclic groups, and the C1-C6 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C6 groups may optionally have 0, 1, or more fluorine atoms substituted; the C1-C12 groups are selected from methylene, ethylene, propylene, butylene, pentylene, hexylene, phenylene, tolylene, ethylphenylene, propylphenylene, pentylene, hexylene, fluorophenylene, biphenylene, or naphthylene.

2. The compound according to claim 1, characterized in that, It has the structure shown in general formula 2, general formula 3, general formula 4 or general formula 5; [General Formula 2]: ； [General Formula 3]: ； [General Formula 4]: ； [General Formula 5]: ； R1, R2, and R3 each independently represent C1 to C6 groups.

3. The compound according to claim 1 or 2, characterized in that, The C1-C6 groups are selected from methyl, ethyl, propyl, butyl, pentyl, or hexyl; the C1-C12 groups are selected from methylene, ethylene, propylene, butylene, pentylene, hexylene, phenylene, tolylene, ethylphenylene, propylphenylene, pentylenephenylene, hexylene, fluorophenylene, biphenylene, or naphthylene.

4. A method for preparing the compound according to any one of claims 1 to 3, characterized in that, include: The first reactant having the following general formula 6 and the second reactant having the following general formula 7 are dissolved in a solvent and stirred to react; After the reaction is complete, the filtrate is collected by filtration and then post-processed to obtain the compound having general formula 1; [General Formula 6]: ; [General Formula 7]: ； In general formulas 6 and 7, A is selected from either an amino group or an isocyanate group, and when A is an amino group, B is an isocyanate group, and when A is an isocyanate group, B is an amino group. R1, R2, and R3 each independently represent C1 to C6 groups, and L1 and L2 each independently represent C1 to C12 groups; Wherein, the C1-C6 groups are straight-chain, branched, or cyclic groups, and the C1-C6 groups are saturated, monounsaturated, or polyunsaturated groups, and the C1-C6 groups may optionally have 0, 1, or more fluorine atoms substituted; the C1-C12 groups are selected from methylene, ethylene, propylene, butylene, pentylene, hexylene, phenylene, tolylene, ethylphenylene, propylphenylene, pentylene, hexylene, fluorophenylene, biphenylene, or naphthylene.

5. The preparation method according to claim 4, characterized in that, The solvent is dichloromethane; and / or, The molar ratio of the first reactant to the second reactant is 1:(0.8~1.2); and / or, The stirring reaction time is 1 to 10 hours.

6. A gas sensor, characterized in that, include: A silicon substrate, including a first surface and a second surface disposed opposite to each other; An insulating layer is disposed on the first surface; A first silicon epitaxial layer and a second silicon epitaxial layer are disposed at intervals on the surface of the insulating layer; Multiple silicon nanoribbons are arranged on the surface of the insulating layer, and their two ends are respectively connected to the first silicon epitaxial layer and the second silicon epitaxial layer; The source and drain are respectively disposed on the surface of the first silicon epitaxial layer and the surface of the second silicon epitaxial layer; A gate is disposed on the second surface; The first silicon epitaxial layer, the second silicon epitaxial layer, and the silicon nanoribbon have the same conductivity type. The silicon nanoribbon surface is modified with any one of the compounds according to claims 1 to 3, wherein the R1, R2, and R3 groups of the compound are substituted so that the compound is covalently connected to the silicon nanoribbon.

7. The gas sensor according to claim 6, characterized in that, The compound is arranged in a single layer on the surface of the silicon nanoribbon.

8. The gas sensor according to claim 6, characterized in that, The silicon nanoribbons extend along a first direction, and the plurality of silicon nanoribbons are uniformly spaced along a second direction; the length of the silicon nanoribbons in the first direction is 10~100 μm, the width of the silicon nanoribbons in the second direction is 100nm~10 μm, and the thickness of the silicon nanoribbons is 10~200 nm. Wherein, the first direction is the direction from the first silicon epitaxial layer to the second silicon epitaxial layer, and the second direction is perpendicular to the first direction.

9. A method for preparing a gas sensor as described in any one of claims 6 to 8, characterized in that, include: A field-effect transistor is provided, the field-effect transistor comprising a silicon substrate, an insulating layer disposed on the surface of the silicon substrate, a first silicon epitaxial layer and a second silicon epitaxial layer disposed at intervals on the surface of the insulating layer, and a plurality of silicon nanoribbons disposed on the surface of the insulating layer and connected at both ends to the first silicon epitaxial layer and the second silicon epitaxial layer, respectively. The field-effect transistor was hydroxylated using a piranha solution to obtain a first silicon wafer, wherein the piranha solution included concentrated sulfuric acid and hydrogen peroxide. A source and a drain are fabricated on the first silicon wafer to obtain a second silicon wafer; A compound having general formula 1 is grafted onto the surface of silicon nanoribbons of the second silicon wafer to obtain a third silicon wafer; A gate is fabricated on the third silicon wafer to obtain the gas sensor.

10. The preparation method according to claim 9, characterized in that, The piranha solution was obtained by mixing 30% hydrogen peroxide and 98% concentrated sulfuric acid in a volume ratio of 3:(7~9); and / or, The hydroxylation treatment specifically involves: placing the field-effect transistor in a container, pouring the piranha solution into the container, heating a water bath, then removing the field-effect transistor, cleaning, and drying it. The temperature of the water bath is 70~95 ℃, and the time is 10~60 min. And / or, The step of grafting a compound having general formula 1 onto the surface of a silicon nanoribbon of the second silicon wafer includes: The compound was dissolved in a solvent to obtain a modified solution; The second silicon wafer is immersed in the modification solution, then removed and dried; Wherein, the concentration of the compound in the modifying solution is 0.02~0.5 mol / L, and the soaking time is 0.5~5 h; and / or, The process further includes, prior to the step of fabricating the gate on the third silicon wafer: The third silicon wafer is immersed in water, then removed and dried; The soaking time is 3 to 10 hours.

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