A self-calibrating gas sensor and a method of manufacturing and drift compensation thereof

Abstract

The application provides a self-calibration gas sensor and a preparation method and a drift compensation method thereof, comprising three sensing units; the three sensing units each comprise a back gate electrode, a dielectric layer, a source electrode and a drain electrode; the first sensing unit further comprises a first two-dimensional material layer and a first organic semiconductor layer which are sequentially located on the dielectric layer; the second sensing unit further comprises a second two-dimensional material layer which is located on the dielectric layer; and the third sensing unit further comprises a second organic semiconductor layer which is located on the dielectric layer. By integrating three functionally complementary sensing units in the same gas sensor, the concentration of a target gas is accurately obtained by using the response difference of the three sensing units to the target gas and background interference, and real-time drift compensation is realized without the need for a reference gas, thereby solving the problem of how to accurately compensate the drift of the gas sensor in real time.

Description

Technical Field

[0001] This invention relates to the field of gas sensor technology, and in particular to a self-calibrating gas sensor, its preparation method, and drift compensation method. Background Technology

[0002] With the large-scale deployment of gas sensors in environmental monitoring, wearable devices, and food preservation, the long-term stability (i.e., signal drift) of gas sensors has become a key bottleneck restricting their practical application. The sources of signal drift in gas sensors mainly include: aging of the sensitive material, slow desorption of adsorbed gases, changes in ambient temperature and humidity, and the filling / release of charge traps in the gate dielectric. Currently, algorithmic compensation or on-chip integration of reference sensors is commonly used to address the signal drift problem of gas sensors.

[0003] However, existing algorithmic compensation methods require collecting a large number of calibration samples at different time points, or periodically recalibrating the sensor using a reference gas (such as pure nitrogen). This not only increases system complexity and operating costs but also fails to achieve continuous monitoring. Existing on-chip integration of reference sensors, because the reference sensor is also sensitive to the target gas, cannot distinguish whether baseline drift is caused by a genuine change in gas concentration or by changes in the environment or the device's own state. Even if a passivation layer is used to cover the surface of the gas sensor's sensitive material to create a reference sensor that only responds to ambient temperature and humidity, this method can only compensate for common-mode interference (drift caused by temperature and humidity), and cannot compensate for baseline drift caused by the slow release of gas adsorbed by the sensitive material itself. Summary of the Invention

[0004] The purpose of this invention is to provide a self-calibrating gas sensor, its preparation method, and a drift compensation method, so as to solve the problem of how to perform accurate drift compensation of a gas sensor in real time.

[0005] To solve the above-mentioned technical problems, the present invention provides a self-calibrating gas sensor, including at least one first sensing unit, at least one second sensing unit and at least one third sensing unit; The first sensing unit includes a first back gate electrode, a first dielectric layer, a first two-dimensional material layer and a first organic semiconductor layer arranged sequentially from bottom to top. A first source electrode and a first drain electrode are respectively arranged on both sides of the first two-dimensional material layer. The second sensing unit includes a second back gate electrode, a second dielectric layer and a second two-dimensional material layer arranged sequentially from bottom to top. A second source electrode and a second drain electrode are respectively arranged on the top two sides of the second two-dimensional material layer. The third sensing unit includes a third back gate electrode, a third dielectric layer and a second organic semiconductor layer arranged sequentially from bottom to top. A third source electrode and a third drain electrode are respectively arranged on the top two sides of the second organic semiconductor layer.

[0006] Optionally, in the self-calibrating gas sensor, the first sensing unit, the second sensing unit, and the third sensing unit are arranged adjacent to each other.

[0007] Optionally, in the self-calibrating gas sensor, the first two-dimensional material layer and the second two-dimensional material layer are made of the same material.

[0008] Optionally, in the self-calibrating gas sensor, the first two-dimensional material layer and the second two-dimensional material layer are made of TMD group N-type two-dimensional semiconductor material or P-type two-dimensional semiconductor material.

[0009] Optionally, in the self-calibrating gas sensor, the first organic semiconductor layer and the second organic semiconductor layer are made of the same material.

[0010] Optionally, in the self-calibrating gas sensor, the first organic semiconductor layer and the second organic semiconductor layer are made of P-type organic semiconductor material.

[0011] Optionally, in the self-calibrating gas sensor, the first back grid electrode, the second back grid electrode, and the third back grid electrode are made of the same material.

[0012] Optionally, in the self-calibrating gas sensor, the first dielectric layer, the second dielectric layer, and the third dielectric layer are made of the same material.

[0013] To address the aforementioned technical problems, the present invention also provides a method for fabricating a self-calibrating gas sensor, used to fabricate the self-calibrating gas sensor as described in any of the preceding claims, the method comprising: Provide a substrate to form the back gate electrode; A dielectric layer is formed on the back gate electrode; A first two-dimensional material layer is formed on a first region of a dielectric layer, a first source electrode and a first drain electrode are formed on both sides of the first two-dimensional material layer, and a first organic semiconductor layer is formed on the top surface of the first two-dimensional material layer, the first source electrode and the first drain electrode to obtain a first sensing unit. A second two-dimensional material layer is formed on the second region of the dielectric layer, and a second source electrode and a second drain electrode are formed on the top two sides of the second two-dimensional material layer, respectively, to obtain a second sensing unit. A second organic semiconductor layer is formed on the third region of the dielectric layer, and a third source electrode and a third drain electrode are formed on the top two sides of the second organic semiconductor layer, respectively, to obtain a third sensing unit.

[0014] Optionally, in the method for fabricating the self-calibrating gas sensor, the first two-dimensional material layer and the second two-dimensional material layer are made of the same material, and the method for obtaining the first sensing unit, the second sensing unit, and the third sensing unit includes: Two-dimensional material thin films were grown using chemical vapor deposition (CVD). Two-dimensional material thin films were transferred onto a dielectric layer using PDMS dry transfer. The two-dimensional material film at the third sensing unit is removed using photolithography and oxygen plasma etching processes.

[0015] Optionally, in the method for fabricating the self-calibrating gas sensor, the first organic semiconductor layer and the second organic semiconductor layer are made of the same material, and the method for obtaining the first sensing unit, the second sensing unit, and the third sensing unit includes: Blocking the second sensing unit; Organic semiconductor materials are deposited at the first sensing unit and the third sensing unit using a shadow mask to form a first organic semiconductor layer at the first sensing unit and a second organic semiconductor layer at the third sensing unit.

[0016] To address the aforementioned technical problems, the present invention also provides a drift compensation method applied to the self-calibrating gas sensor described in any of the preceding claims, wherein the drift compensation method comprises: Acquire the response signals of each of the first, second, and third sensing units in the self-calibrating gas sensor under the current environment; A linear regression model is constructed using the response signals of all the first, second, and third sensing units. Based on the linear regression model, the gas concentration and time drift of the self-calibrating gas sensor in the current environment are calculated in real time. The time drift is used to compensate for the drift of the self-calibrating gas sensor.

[0017] Optionally, in the drift compensation method, the method for obtaining the response signal of each of the first sensing unit, the second sensing unit, and the third sensing unit in the self-calibrating gas sensor under the current environment includes: The self-calibrating gas sensor was placed in a clean air environment to obtain the reference current of each of the first, second, and third sensing units. The self-calibrated gas sensor was placed in the current environment, and the steady-state current of each of the first, second, and third sensing units was obtained. Using the reference current and steady-state current, the response values ​​of each of the first, second, and third sensing units are calculated as response signals.

[0018] Optionally, in the drift compensation method, the formula for calculating the response value is:

[0019] Where R represents the response value of the first sensing unit, the second sensing unit, or the third sensing unit. This represents the steady-state current of the first, second, or third sensing unit in the current environment. This represents the reference current of the first, second, or third sensing unit in a clean air environment.

[0020] Optionally, in the drift compensation method, the linear regression model is expressed as:

[0021] Wherein, S represents the response signal corresponding to the first sensing unit, the second sensing unit, or the third sensing unit. The current ambient gas concentration is represented by T, the current ambient temperature is represented by H, and the current ambient humidity is represented by H. Indicates the amount of time drift; , , and The response coefficient is determined through a pre-calibration experiment. This indicates measurement noise.

[0022] The self-calibrating gas sensor, its fabrication method, and drift compensation method provided by this invention include at least one first sensing unit, at least one second sensing unit, and at least one third sensing unit. The first sensing unit comprises, from bottom to top, a first back gate electrode, a first dielectric layer, a first two-dimensional material layer, and a first organic semiconductor layer, with a first source electrode and a first drain electrode respectively disposed on both sides of the first two-dimensional material layer. The second sensing unit comprises, from bottom to top, a second back gate electrode, a second dielectric layer, and a second two-dimensional material layer, with a second source electrode and a second drain electrode respectively disposed on both sides of the top of the second two-dimensional material layer. The third sensing unit comprises, from bottom to top, a third back gate electrode, a third dielectric layer, and a second organic semiconductor layer, with a third source electrode and a third drain electrode respectively disposed on both sides of the top of the second organic semiconductor layer. By integrating three functionally complementary sensing units in the same gas sensor, the concentration of the target gas can be accurately obtained by utilizing the differences in response to the target gas and the differences in response to background interference among the three sensing units. Real-time drift compensation is achieved without the need for a reference gas, solving the problem of how to perform accurate drift compensation for gas sensors in real time. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of the self-calibrating gas sensor provided in this embodiment; Figure 2 This is a flowchart illustrating the fabrication method of the self-calibrating gas sensor provided in this embodiment; Figures 3(A) to 3(E) are schematic diagrams of the device structure corresponding to each step in the preparation method provided in this embodiment; Figure 4 This is a flowchart of the drift compensation method provided in this embodiment; The labels in the accompanying drawings are explained as follows: A - First sensing unit; 110 - First back gate electrode; 120 - First dielectric layer; 130 - First two-dimensional material layer; 140 - First organic semiconductor layer; 151 - First source electrode; 152 - First drain electrode; B - Second sensing unit; 210 - Second back gate electrode; 220 - Second dielectric layer; 230 - Second two-dimensional material layer; 241 - Second source electrode; 242 - Second drain electrode; C - Third sensing unit; 310 - Third back gate electrode; 320 - Third dielectric layer; 330 - Second organic semiconductor layer; 341 - Third source electrode; 342 - Third drain electrode. Detailed Implementation

[0024] The self-calibrating gas sensor, its preparation method, and drift compensation method proposed in this invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that the drawings are all in a very simplified form and use non-precise scales, used only to facilitate and clarify the illustration of the embodiments of this invention. Furthermore, the structures shown in the drawings are often part of the actual structure. In particular, different figures may emphasize different aspects and sometimes use different scales.

[0025] It should be noted that the terms "first," "second," etc., used in the specification, claims, and drawings of this invention are used to distinguish similar objects in order to describe embodiments of the invention, and are not used to describe a specific order or sequence. It should be understood that such uses of terminology are interchangeable where appropriate. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] This embodiment provides a self-calibrating gas sensor, such as... Figure 1 As shown, it includes at least one first sensing unit A, at least one second sensing unit B, and at least one third sensing unit C; wherein, The first sensing unit A includes a first back gate electrode 110, a first dielectric layer 120, a first two-dimensional material layer 130 and a first organic semiconductor layer 140 arranged sequentially from bottom to top. A first source electrode 151 and a first drain electrode 152 are respectively arranged on both sides of the first two-dimensional material layer 130. The second sensing unit B includes a second back gate electrode 210, a second dielectric layer 220 and a second two-dimensional material layer 230 arranged sequentially from bottom to top. A second source electrode 241 and a second drain electrode 242 are respectively arranged on the top two sides of the second two-dimensional material layer 230. The third sensing unit C includes a third back gate electrode 310, a third dielectric layer 320 and a second organic semiconductor layer 330 arranged sequentially from bottom to top. A third source electrode 341 and a third drain electrode 342 are respectively arranged on the top two sides of the second organic semiconductor layer 330.

[0027] In this embodiment, the channel of the first sensing unit A comprises a vertical heterojunction formed by a first two-dimensional material layer 130 and a first organic semiconductor layer 140. Therefore, the first sensing unit A can utilize the first two-dimensional material layer 130 to provide high mobility and photoresponse, and the first organic semiconductor layer 140 to provide high gas adsorption capacity and selectivity. The response amplitude of the first sensing unit A is typically greater than that of the second sensing unit B and the third sensing unit C, and the first sensing unit A is significantly affected by interface effects.

[0028] Furthermore, in this embodiment, the channel of the second sensing unit B includes a second two-dimensional material layer 230. Therefore, the response of the second sensing unit B to the target gas mainly originates from the surface charge transfer of the second two-dimensional material layer 230. The second sensing unit B has a moderate response amplitude and a fast response speed, but is sensitive to humidity.

[0029] Furthermore, in this embodiment, the channel of the third sensing unit C includes a second organic semiconductor layer 330. The interaction between the second organic semiconductor layer 330 and the gas is primarily through physical adsorption and π electron donor-acceptor interactions. Its responses to NH3 (electron-donating gas) and NO2 (electron-withdrawing gas) exhibit opposite polarities and typically have longer recovery times.

[0030] The self-calibrating gas sensor provided in this embodiment integrates three complementary sensing units in the same gas sensor. By utilizing the differences in the response of the three sensing units to the target gas and the differences in their response to background interference, the concentration of the target gas can be accurately obtained. Real-time drift compensation can be achieved without the need for a reference gas, thus solving the problem of how to perform accurate drift compensation for gas sensors in real time.

[0031] Specifically, in this embodiment, the first sensing unit A, the second sensing unit B, and the third sensing unit C are arranged adjacent to each other, so that the three sensing units are in the same environmental conditions. The environmental conditions include temperature, humidity, gas, light, electrical bias history, etc. In this way, the common-mode interference (such as temperature drift, power fluctuation, etc.) experienced by the three sensing units is shown to have a certain correlation in the response signal.

[0032] Furthermore, in order to avoid the difference in response between the first sensing unit A and the second sensing unit B due to the different materials of the first two-dimensional material layer 130 and the second two-dimensional material layer 230, and in order to reduce the difficulty of the process, in this embodiment, the first two-dimensional material layer 130 and the second two-dimensional material layer 230 are made of the same material.

[0033] Specifically, in this embodiment, the first two-dimensional material layer 130 and the second two-dimensional material layer 230 are made of TMD (Transition Metal Dichalcogenides) group N-type two-dimensional semiconductor materials or P-type two-dimensional semiconductor materials. For example, they can be one or more of MoS2, WS2, WSe2, MoSe2, MoTe2, and PdSe2 to obtain a single-layer structure or a multi-layer structure for the first two-dimensional material layer 130 and the second two-dimensional material layer 230.

[0034] Furthermore, in this embodiment, the first two-dimensional material layer 130 and the second two-dimensional material layer 230 have the same thickness, for example, the thickness can be 1~20nm.

[0035] Furthermore, in order to avoid the response difference between the first sensing unit A and the third sensing unit C due to the different materials of the first organic semiconductor layer 140 and the second organic semiconductor layer 330, and in order to reduce the difficulty of the process, in this embodiment, the first organic semiconductor layer 140 and the second organic semiconductor layer 330 are made of the same material.

[0036] Specifically, in this embodiment, the first organic semiconductor layer 140 and the second organic semiconductor layer 330 are made of P-type organic semiconductor materials. For example, they can be C8-BTBT, pentacene, DNTT, or P3HT.

[0037] Furthermore, in this embodiment, the first organic semiconductor layer 140 and the second organic semiconductor layer 330 have the same thickness, for example, the thickness can be 1~50nm.

[0038] Furthermore, to reduce manufacturing complexity, in this embodiment, the first back gate electrode 110, the second back gate electrode 210, and the third back gate electrode 310 are made of the same material. For example, they are metals (such as Ti, Au, Cr, Pt, W, etc.), metal stacks (such as Ti / Au stacks, Cr / Au stacks, Ti / Pt stacks, Cr / Pt stacks, etc.), or indium tin oxide (ITO).

[0039] Furthermore, the first back gate electrode 110, the second back gate electrode 210, and the third back gate electrode 310 have the same thickness. Specifically, when the back gate electrode is made of metal, its thickness is 50-80 nm; when the back gate electrode is made of a metal stack, its thickness is 55-95 nm, wherein the bottom layer (Ti or Cr) serves as an adhesion layer with a thickness of 5-15 nm, and the top layer (Au or Pt) serves as the gate electrode with a thickness of 50-80 nm; and when the back gate electrode is made of indium tin oxide, its thickness is 50-200 nm.

[0040] In practical applications, the first sensing unit A, the second sensing unit B, and the third sensing unit C can share a single back gate electrode or form their own independent back gate electrodes. This application does not impose any restrictions on this.

[0041] Furthermore, to reduce manufacturing complexity, in this embodiment, the first dielectric layer 120, the second dielectric layer 220, and the third dielectric layer 320 are made of the same material. For example, they are silicon oxide, aluminum oxide, or organic insulating materials, wherein the organic insulating material can specifically be PMMA, PPC, etc.

[0042] Furthermore, the first dielectric layer 120, the second dielectric layer 220, and the third dielectric layer 320 have the same thickness, for example, the thickness can be 10~50nm.

[0043] Furthermore, in this embodiment, the first source electrode 151 is made of metal or a metal stack; the first drain electrode 152 is made of metal or a metal stack; the thickness of the first source electrode 151 is 50~80nm; and the thickness of the first drain electrode 152 is 50~80nm.

[0044] Furthermore, the material of the second source electrode 241 is metal or a metal stack; the material of the second drain electrode 242 is metal or a metal stack; the thickness of the second source electrode 241 is 50~80nm; and the thickness of the second drain electrode 242 is 50~80nm.

[0045] Furthermore, the material of the third source electrode 341 is metal or a metal stack; the material of the third drain electrode 342 is metal or a metal stack; the thickness of the third source electrode 341 is 50~80nm; and the thickness of the third drain electrode 342 is 50~80nm.

[0046] Preferably, the first source electrode 151, the first drain electrode 152, the second source electrode 241, the second drain electrode 242, the third source electrode 341, and the third drain electrode 342 are made of the same material.

[0047] More preferably, the thicknesses of the first source electrode 151, the first drain electrode 152, the second source electrode 241, the second drain electrode 242, the third source electrode 341, and the third drain electrode 342 can be made consistent, thereby reducing the complexity of the process.

[0048] The self-calibrating gas sensor provided in this embodiment utilizes the inherent response differences of the three sensing units to decouple gas concentration from interference / drift in real time, significantly reducing maintenance costs. Simultaneously, by using the three sensing units for dynamic drift estimation, it can still provide accurate concentration readings even as sensitive materials slowly age, extending the lifespan of the gas sensor. The self-calibrating gas sensor provided in this embodiment has automatic suppression capabilities against common-mode interference such as temperature, humidity, and light, making it particularly suitable for outdoor environmental monitoring and wearable devices. The self-calibrating gas sensor provided in this embodiment features a feature vector dimension of 3 for the three sensing units, and the differentiated responses to polar gases significantly enhance the ability to distinguish mixed gases. The self-calibrating gas sensor provided in this embodiment integrates the three sensing units onto a single chip, which is beneficial for miniaturization and low-power design.

[0049] This embodiment also provides a method for preparing a self-calibrating gas sensor, used to prepare the self-calibrating gas sensor as described above, such as... Figure 2 As shown, the preparation method includes: S1 provides a substrate to form the back gate electrode.

[0050] In practical applications, the substrate can be a silicon substrate, a silicon oxide substrate, or a PET (polyethylene terephthalate) substrate. This application does not specify the specific material of the substrate. Specifically, a physical vapor deposition (PVD) process can be used to deposit metal, metal stacks, or indium tin oxide on the substrate to form the back gate electrode.

[0051] When the substrate material is PET, ITO (indium tin oxide) can be formed on the substrate as the back gate electrode.

[0052] In this embodiment, as shown in FIG3(A), the substrate is highly doped to obtain the back gate electrode. For example, the silicon substrate is heavily p-doped, such as a boron-doped silicon substrate, so that the heavily doped substrate serves as the back gate electrode.

[0053] In practical applications, as shown in Figure 3(A), the first back gate electrode 110 of the first sensing unit A, the second back gate electrode 210 of the second sensing unit B, and the third back gate electrode 310 of the third sensing unit C can share the same back gate electrode.

[0054] In the process of forming independent first back gate electrodes 110, second back gate electrodes 210, and third back gate electrodes 310 in the first sensing unit A, the second sensing unit B, and the third sensing unit C, after forming complete back gate electrodes on the substrate, photolithography can be used to remove the back gate electrodes outside the regions of the first sensing unit A, the second sensing unit B, and the third sensing unit C according to the regions divided on the substrate, so that independent first back gate electrodes 110, second back gate electrodes 210, and third back gate electrodes 310 are correspondingly obtained on the regions of the first sensing unit A, the second sensing unit B, and the third sensing unit C on the substrate.

[0055] S2, a dielectric layer is formed on the back gate electrode.

[0056] Specifically, in this embodiment, as shown in FIG3(B), a dielectric layer is formed on the back gate electrode using atomic layer deposition (ALD), spin coating, or plasma-enhanced chemical vapor deposition (PECVD) processes. Specifically, a first dielectric layer 120 is formed on the region where the first back gate electrode 110 is located (the region of the first sensing unit A), a second dielectric layer 220 is formed on the region where the second back gate electrode 210 is located (the region of the second sensing unit B), and a third dielectric layer 320 is formed on the region where the third back gate electrode 310 is located (the region of the third sensing unit C).

[0057] In practical applications, after forming a complete dielectric layer on the complete back gate electrode, a photolithography etching process can be used to remove the back gate electrode and dielectric layer outside the regions of the first sensing unit A, the second sensing unit B, and the third sensing unit C, according to the regions defined on the substrate. This results in independent first back gate electrodes 110, 210, and 310, and independent first dielectric layers 120, 220, and 320 on the regions of the first sensing unit A, the second sensing unit B, and the third sensing unit C on the substrate. Alternatively, a self-aligned process can be used to form the first dielectric layer 120, the second dielectric layer 220, and the third dielectric layer 320 on the first back gate electrode 110, the second back gate electrode 210, and the third back gate electrode 310, respectively.

[0058] S3, a first two-dimensional material layer is formed on the first region of the dielectric layer, a first source electrode and a first drain electrode are formed on both sides of the first two-dimensional material layer, and a first organic semiconductor layer is formed on the top surface of the first two-dimensional material layer, the first source electrode and the first drain electrode to obtain the first sensing unit.

[0059] S4, a second two-dimensional material layer is formed on the second region of the dielectric layer, and a second source electrode and a second drain electrode are formed on the top two sides of the second two-dimensional material layer respectively to obtain a second sensing unit; S5, a second organic semiconductor layer is formed on the third region of the dielectric layer, and a third source electrode and a third drain electrode are formed on the top two sides of the second organic semiconductor layer respectively to obtain a third sensing unit.

[0060] Specifically, in this embodiment, as shown in Figure 3(C), a two-dimensional material thin film is first grown using chemical vapor deposition; then, the two-dimensional material thin film is transferred onto the dielectric layer using PDMS (polydimethylsiloxane) dry transfer; finally, the two-dimensional material thin film at the third sensing unit C is removed using photolithography and oxygen plasma etching processes. At this time, the first two-dimensional material layer 130 and the second two-dimensional material layer 230 are simultaneously obtained at the first sensing unit A and the second sensing unit B.

[0061] Then, in this embodiment, as shown in FIG3(D), the second sensing unit B is shielded; then, organic semiconductor materials are deposited at the first sensing unit A and the third sensing unit C using a shadow mask to form a first organic semiconductor layer 140 at the first sensing unit A and a second organic semiconductor layer 330 at the third sensing unit C; finally, the shielding material is removed. At this time, the first organic semiconductor layer 140 and the second organic semiconductor layer 330 are simultaneously obtained at the first sensing unit A and the third sensing unit C.

[0062] Finally, in this embodiment, as shown in FIG3(E), electron beam lithography is used to define the first source electrode 151 and the first drain electrode 152 at the first sensing unit A, the second source electrode 241 and the second drain electrode 242 at the second sensing unit B, and the third source electrode 341 and the third drain electrode 342 at the third sensing unit C. The first source electrode 151 and the first drain electrode 152 are formed on both sides of the first two-dimensional material layer 130, the second source electrode 241 and the second drain electrode 242 are formed on both sides of the top of the second two-dimensional material layer 230, and the third source electrode 341 and the third drain electrode 342 are formed on both sides of the top of the second organic semiconductor layer 330.

[0063] In one specific embodiment, silicon oxide is used as the substrate, with a thickness of 300 nm and a length and width of 1 cm. A 50 nm thick Ti layer is deposited as the back gate electrode (shared gate electrode) using a PVD process. A 30 nm thick aluminum oxide layer is deposited as the dielectric layer using an ALD process. A 1 nm thick MoS2 film grown by a CVD process is transferred to the target position surface of the dielectric layer using a PDMS dry transfer method. The MoS2 film at the second sensing unit B is removed using photolithography and oxygen plasma etching. The second sensing unit B is masked, and a 30 nm thick C8-BTBT layer is deposited at the first sensing unit A and the third sensing unit C using a shadow mask. The source and drain electrodes of the first sensing unit A, the second sensing unit B, and the third sensing unit C are defined using electron beam lithography, resulting in a 50 nm thick Ti / Au material first source electrode, first drain electrode, second source electrode, second drain electrode, third source electrode, and third drain electrode.

[0064] The self-calibrating gas sensor fabrication method provided in this embodiment is fully compatible with CMOS technology, exhibits high process consistency, is easy to mass-produce, and has a simple manufacturing process and high yield. The fabricated self-calibrating gas sensor accurately obtains the concentration of the target gas by utilizing the differences in response to the target gas and the differences in response to background interference among the three sensing units. It also achieves real-time drift compensation without the need for a reference gas, solving the problem of how to perform accurate drift compensation for gas sensors in real time.

[0065] Furthermore, this embodiment also provides a drift compensation method, applied to the self-calibrating gas sensor described above, such as... Figure 4 As shown, the drift compensation method includes: P1 acquires the response signals of each of the first, second, and third sensing units in the self-calibrating gas sensor under the current environment.

[0066] Specifically, in this embodiment, the self-calibrating gas sensor is first placed in a clean air environment to acquire the reference current of each of the first sensing unit A, the second sensing unit B, and the third sensing unit C. It should be noted that the reference current of different sensing units needs to be acquired and recorded separately.

[0067] Then, the self-calibrating gas sensor is placed in the current environment, and the steady-state current of each of the first sensing unit A, the second sensing unit B, and the third sensing unit C is acquired. It should be noted that the steady-state current of different sensing units also needs to be acquired and recorded individually. Furthermore, the self-calibrating gas sensor needs to be restored before changing the environment to ensure the accuracy of the measurement results.

[0068] In practical applications, the gate voltage and drain voltage used for the reference current and the steady-state current are kept constant. Specifically, the gate voltage and drain voltage of all sensing units can be made consistent to facilitate the control of the gate and drain voltages and ensure the accuracy of subsequent calculation results.

[0069] The methods for obtaining the reference current and steady-state current are well known to those skilled in the art, and will not be described in detail here.

[0070] Finally, using the reference current and steady-state current, the response values ​​of each of the first, second, and third sensing units are calculated as response signals. This embodiment provides the formula for calculating the response values ​​as follows:

[0071] Where R represents the response value of the first sensing unit, the second sensing unit, or the third sensing unit. This represents the steady-state current of the first, second, or third sensing unit in the current environment. This represents the reference current of the first, second, or third sensing unit in a clean air environment.

[0072] In this way, the response value of each sensing unit can be obtained.

[0073] P2, using the response signals of all the first, second, and third sensing units, constructs a linear regression model.

[0074] Specifically, in this embodiment, a linear regression model can be constructed for each type of sensing unit, and the linear regression model is expressed as follows:

[0075] Wherein, S represents the response signal corresponding to the first sensing unit, the second sensing unit, or the third sensing unit. The current ambient gas concentration is represented by T, the current ambient temperature is represented by H, and the current ambient humidity is represented by H. Indicates the amount of time drift; , , and The response coefficient is determined through a pre-calibration experiment. This indicates measurement noise.

[0076] In other words, the response signals of the first sensing unit A, the second sensing unit B, and the third sensing unit C provided in this embodiment are all linear regression functions of gas concentration, ambient temperature, ambient humidity, time drift, and measurement noise. Thus, linear regression models corresponding to the three sensing units are obtained.

[0077] P3, based on a linear regression model, calculates in real time the gas concentration and time drift of the self-calibrating gas sensor in the current environment.

[0078] Specifically, in this embodiment, there are three types of sensing units, and the response coefficients of the three sensing units are determined through pre-calibration experiments. , , and Since they are linearly independent, when the response values ​​S, ambient temperature T, and humidity H corresponding to the three sensing units are known, the gas concentration can be obtained by simultaneously solving the three linear regression functions corresponding to the three sensing units. and time drift The unique solution, for example, by real-time calculation of gas concentration using the least squares method or Kalman filtering. And estimate the time drift. .

[0079] In practical applications, the gas concentration can be calculated using a decoupling algorithm based on the threshold of an on-chip microcontroller (MCU) and a pre-calibrated response coefficient matrix, based on parameters such as the input response value S, ambient temperature T, and humidity H. and time drift .

[0080] P4 uses time drift to compensate for drift in the self-calibrating gas sensor.

[0081] Specifically, in practical applications, the time drift can be dynamically self-calibrated according to a preset cycle to achieve drift compensation and long-term stable detection.

[0082] Ideally, the reference current of each sensor can be updated periodically according to actual needs to avoid compensation inaccuracies caused by device aging.

[0083] The drift compensation method provided in this embodiment utilizes the inherent response differences among the three sensing units to decouple gas concentration from interference / drift in real time, significantly reducing system maintenance costs. Through dynamic drift estimation, the drift compensation method provided in this embodiment can still provide accurate concentration readings even when sensitive materials are slowly aging, eliminating the need for frequent sensor replacements.

[0084] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to mutually. In addition, different parts between embodiments can also be combined with each other, and this invention does not limit this.

[0085] The self-calibrating gas sensor, its fabrication method, and drift compensation method provided in this embodiment include at least one first sensing unit, at least one second sensing unit, and at least one third sensing unit. The first sensing unit comprises, from bottom to top, a first back gate electrode, a first dielectric layer, a first two-dimensional material layer, and a first organic semiconductor layer. A first source electrode and a first drain electrode are respectively disposed on both sides of the first two-dimensional material layer. The second sensing unit comprises, from bottom to top, a second back gate electrode, a second dielectric layer, and a second two-dimensional material layer. A second source electrode and a second drain electrode are respectively disposed on both sides of the top of the second two-dimensional material layer. The third sensing unit comprises, from bottom to top, a third back gate electrode, a third dielectric layer, and a second organic semiconductor layer. A third source electrode and a third drain electrode are respectively disposed on both sides of the top of the second organic semiconductor layer. By integrating three functionally complementary sensing units in the same gas sensor, the concentration of the target gas can be accurately obtained by utilizing the differences in response to the target gas and the differences in response to background interference among the three sensing units. Real-time drift compensation is achieved without the need for a reference gas, solving the problem of how to perform accurate drift compensation for gas sensors in real time.

[0086] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A self-calibrating gas sensor, characterized in that, It includes at least one first sensing unit, at least one second sensing unit, and at least one third sensing unit; The first sensing unit includes a first back gate electrode, a first dielectric layer, a first two-dimensional material layer and a first organic semiconductor layer arranged sequentially from bottom to top. A first source electrode and a first drain electrode are respectively arranged on both sides of the first two-dimensional material layer. The second sensing unit includes a second back gate electrode, a second dielectric layer and a second two-dimensional material layer arranged sequentially from bottom to top. A second source electrode and a second drain electrode are respectively arranged on the top two sides of the second two-dimensional material layer. The third sensing unit includes a third back gate electrode, a third dielectric layer and a second organic semiconductor layer arranged sequentially from bottom to top. A third source electrode and a third drain electrode are respectively arranged on the top two sides of the second organic semiconductor layer. The first two-dimensional material layer and the second two-dimensional material layer are made of the same material; the first organic semiconductor layer and the second organic semiconductor layer are made of the same material.

2. The self-calibrating gas sensor according to claim 1, characterized in that, The first sensing unit, the second sensing unit, and the third sensing unit are arranged adjacent to each other.

3. The self-calibrating gas sensor according to claim 1, characterized in that, The first two-dimensional material layer and the second two-dimensional material layer are made of TMD family N-type two-dimensional semiconductor material or P-type two-dimensional semiconductor material.

4. The self-calibrating gas sensor according to claim 1, characterized in that, The first organic semiconductor layer and the second organic semiconductor layer are made of P-type organic semiconductor material.

5. The self-calibrating gas sensor according to claim 1, characterized in that, The first back gate electrode, the second back gate electrode, and the third back gate electrode are made of the same material.

6. The self-calibrating gas sensor according to claim 1, characterized in that, The first dielectric layer, the second dielectric layer, and the third dielectric layer are made of the same material.

7. A method for preparing a self-calibrating gas sensor, used to prepare the self-calibrating gas sensor as described in any one of claims 1 to 6, characterized in that, The preparation method includes: Provide a substrate to form the back gate electrode; A dielectric layer is formed on the back gate electrode; A first two-dimensional material layer is formed on a first region of a dielectric layer, a first source electrode and a first drain electrode are formed on both sides of the first two-dimensional material layer, and a first organic semiconductor layer is formed on the top surface of the first two-dimensional material layer, the first source electrode and the first drain electrode to obtain a first sensing unit. A second two-dimensional material layer is formed on the second region of the dielectric layer, and a second source electrode and a second drain electrode are formed on the top two sides of the second two-dimensional material layer, respectively, to obtain a second sensing unit. A second organic semiconductor layer is formed on the third region of the dielectric layer, and a third source electrode and a third drain electrode are formed on the top two sides of the second organic semiconductor layer, respectively, to obtain a third sensing unit.

8. The method for preparing a self-calibrating gas sensor according to claim 7, characterized in that, The method for obtaining the first sensing unit, the second sensing unit, and the third sensing unit, wherein the first two-dimensional material layer and the second two-dimensional material layer are made of the same material, includes: Two-dimensional material thin films were grown using chemical vapor deposition (CVD). Two-dimensional material thin films were transferred onto a dielectric layer using PDMS dry transfer. The two-dimensional material film at the third sensing unit is removed using photolithography and oxygen plasma etching processes.

9. The method for preparing a self-calibrating gas sensor according to claim 7, characterized in that, The first organic semiconductor layer and the second organic semiconductor layer are made of the same material. The method for obtaining the first sensing unit, the second sensing unit, and the third sensing unit includes: Blocking the second sensing unit; Organic semiconductor materials are deposited at the first sensing unit and the third sensing unit using a shadow mask to form a first organic semiconductor layer at the first sensing unit and a second organic semiconductor layer at the third sensing unit.

10. A drift compensation method, applied to a self-calibrating gas sensor as described in any one of claims 1 to 6, characterized in that, The drift compensation method includes: Acquire the response signals of each of the first, second, and third sensing units in the self-calibrating gas sensor under the current environment; A linear regression model is constructed using the response signals of all the first, second, and third sensing units. Based on the linear regression model, the gas concentration and time drift of the self-calibrating gas sensor in the current environment are calculated in real time. The time drift is used to compensate for the drift of the self-calibrating gas sensor.

11. The drift compensation method according to claim 10, characterized in that, The method for obtaining the response signals of each of the first sensing unit, the second sensing unit, and the third sensing unit in the self-calibrating gas sensor under the current environment includes: The self-calibrating gas sensor was placed in a clean air environment to obtain the reference current of each of the first, second, and third sensing units. The self-calibrated gas sensor was placed in the current environment, and the steady-state current of each of the first, second, and third sensing units was obtained. Using the reference current and steady-state current, the response values ​​of each of the first, second, and third sensing units are calculated as response signals.

12. The drift compensation method according to claim 11, characterized in that, The formula for calculating the response value is: Where R represents the response value of the first sensing unit, the second sensing unit, or the third sensing unit. This represents the steady-state current of the first, second, or third sensing unit in the current environment. This represents the reference current of the first, second, or third sensing unit in a clean air environment.

13. The drift compensation method according to claim 11, characterized in that, The linear regression model is expressed as follows: Wherein, S represents the response signal corresponding to the first sensing unit, the second sensing unit, or the third sensing unit. The current ambient gas concentration is represented by T, the current ambient temperature is represented by H, and the current ambient humidity is represented by H. Indicates the amount of time drift; , , and The response coefficient is determined through a pre-calibration experiment. This indicates measurement noise.

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