Infrared detector sensitive element structure, preparation method and infrared detector

Abstract

The invention discloses an infrared detector sensitive element structure, a preparation method and an infrared detector, and is applied to the field of infrared detection.The infrared detector sensitive element structure comprises a first electrode, a pyroelectric functional layer and a second electrode; the pyroelectric functional layer is a polyvinylidene fluoride based copolymer thin film layer, and the polyvinylidene fluoride based copolymer thin film layer directly absorbs infrared light; the first electrode is arranged on the surface of one side of the pyroelectric functional layer, the second electrode is arranged on the surface of the other side of the pyroelectric functional layer, and the surface, provided with the second electrode, of the pyroelectric functional layer is an infrared light incident surface; the second electrode is a single-layer graphene electrode; and the single-layer graphene electrode has permeability to infrared light. The polyvinylidene fluoride-based copolymer film layer is used as a pyroelectric functional layer, and the single-layer graphene electrode is used as an electrode of an infrared light incidence side, so that the thickness of the functional layer can be reduced, and the functional layer is enabled to directly dominate absorption of infrared radiation, thereby reducing the heat capacity of the device, and improving the response sensitivity and response speed of the device.

Description

Technical Field

[0001] This invention relates to the field of infrared detection, and in particular to a sensitive element structure, fabrication method, and infrared detector. Background Technology

[0002] Taking pyroelectric infrared detectors as an example, these detectors have the advantages of simple structure, excellent performance, and low cost, and are widely used in infrared detection scenarios. Pyroelectric infrared detectors work by absorbing infrared radiation, causing a temperature change in the pyroelectric material within the sensor element, thereby generating a pyroelectric current signal. Therefore, the greater the absorption rate of the sensor element to infrared radiation and the smaller its heat capacity, the greater the temperature change and the better the device's performance.

[0003] Commonly used pyroelectric materials in existing technologies include lead zirconate titanate ceramics, lithium tantalate single crystals, and triglycine sulfate. However, these pyroelectric materials themselves do not absorb infrared radiation, requiring the fabrication of an additional infrared absorption layer. This additional layer increases the overall heat capacity of the device, reducing its performance and responsivity. Furthermore, it increases the fabrication difficulty and cost. Since the infrared radiation is absorbed in the absorption layer, heat needs to be conducted to the pyroelectric functional layer to generate a temperature change and thus a pyroelectric current, further reducing the device's response speed. Existing pyroelectric materials based on polyvinylidene fluoride (PVDF) or its copolymers with trifluoroethylene (hereinafter referred to as PVDF) are high-performance pyroelectric materials. Their processing is simple and pollution-free, making them suitable for fabricating high-performance uncooled infrared detectors. PVDF itself has strong absorption of infrared radiation in the 7-20 micrometer wavelength band, allowing for the use of an interferometric cavity structure without an additional absorption layer, thus achieving the absorption of infrared radiation by the sensor element. This reduces the device's heat capacity, improves its performance, simplifies the fabrication process, and lowers costs. Currently, the commonly used upper electrode in interference cavity structures employs a semi-permeable metal membrane with a thickness of approximately 10 nanometers. Simulation calculations show that further reducing the thickness of the semi-permeable metal membrane can further improve the absorption rate of the sensor for infrared radiation. However, due to limitations in metal thin film fabrication processes, further reducing the metal thickness would prevent the formation of a continuous thin film, reducing the effective area of ​​the upper electrode and consequently degrading the apparent performance of the device.

[0004] Therefore, how to provide a PVDF-based polymer pyroelectric material layer that can directly absorb infrared radiation, avoid the absorption of infrared radiation by an additional absorption layer, and at the same time reduce the heat capacity of the device is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a sensitive element structure, preparation method and infrared detector for an infrared detector, which solves the problem that in the prior art, the pyroelectric material itself does not absorb infrared radiation, so an additional infrared absorption layer needs to be prepared. The additional infrared absorption layer increases the overall heat capacity of the device, reduces the device performance, reduces the device responsivity, increases the difficulty and cost of device preparation and reduces the response speed of the device.

[0006] To solve the above-mentioned technical problems, the present invention provides an infrared detector sensitive element structure, comprising:

[0007] A first electrode, a pyroelectric functional layer, and a second electrode; the pyroelectric functional layer is a polyvinylidene fluoride vinyl copolymer film layer, which directly absorbs infrared light;

[0008] The first electrode is disposed on one side surface of the pyroelectric functional layer, the second electrode is disposed on the other side surface of the pyroelectric functional layer, and the surface of the pyroelectric functional layer on which the second electrode is disposed is the infrared light incident surface.

[0009] The second electrode is a single-layer graphene electrode; the single-layer graphene electrode is transparent to infrared light.

[0010] Optionally, the thickness of the pyroelectric functional layer is 1 micrometer to 3 micrometers.

[0011] Optionally, the first electrode includes at least one of an aluminum electrode, a gold electrode, a silver electrode, a platinum electrode, and a nickel-chromium electrode.

[0012] Optionally, the thickness of the first electrode is 50 nanometers to 100 nanometers.

[0013] Optionally, a substrate may also be included;

[0014] The substrate is disposed on the side of the first electrode opposite to the pyroelectric functional layer.

[0015] This invention also provides a method for fabricating a sensitive element structure for an infrared detector, comprising:

[0016] A structure to be processed is provided; the structure to be processed includes at least a polyvinylidene fluoride (PVDF) vinyl copolymer film layer, and a first electrode is prepared on the non-infrared light incident surface of the PVDF vinyl copolymer film layer; the PVDF vinyl copolymer film layer directly absorbs infrared light.

[0017] A monolayer graphene electrode is prepared on the infrared light incident surface of the polyvinylidene fluoride vinyl copolymer film layer; the monolayer graphene electrode is transparent to infrared light.

[0018] Optionally, it is applied to the fabrication of a sensitive elemental structure with a substrate, wherein a structure to be processed is provided, comprising:

[0019] A substrate is provided, and the first electrode is fabricated on the surface of the substrate;

[0020] A polyvinylidene fluoride vinyl copolymer thin film layer is prepared on the surface of the first electrode to obtain the structure to be processed.

[0021] Optionally, the step of preparing the polyvinylidene fluoride vinyl copolymer thin film layer on the surface of the first electrode includes:

[0022] The polyvinylidene fluoride vinyl copolymer thin film layer is prepared on the surface of the first electrode using spin coating, casting, or the Langmuir-Braggette method.

[0023] Optionally, the preparation of a monolayer graphene electrode on the infrared light incident surface of the polyvinylidene fluoride vinyl copolymer film layer includes:

[0024] The monolayer graphene electrode was prepared by mechanical exfoliation or chemical vapor deposition.

[0025] The monolayer graphene electrode was transferred to the infrared light incident surface of the polyvinylidene fluoride vinyl copolymer film using a transfer method.

[0026] Optionally, this method is applied to the fabrication of substrate-free sensitive metastructures, wherein a structure to be processed is provided, comprising:

[0027] Provides the polyvinylidene fluoride vinyl copolymer film layer prepared by a stretching method;

[0028] The first electrode is prepared on the non-infrared light incident surface of the polyvinylidene fluoride vinyl copolymer film layer to obtain the structure to be processed.

[0029] The present invention also provides an infrared detector, including the infrared detector sensitive element structure as described above.

[0030] As can be seen, the infrared detector sensitive element structure provided by this invention includes a first electrode, a pyroelectric functional layer, and a second electrode. The pyroelectric functional layer is a polyvinylidene fluoride (PVDF) vinyl copolymer thin film layer, which directly absorbs infrared light. The first electrode is disposed on one side surface of the pyroelectric functional layer, and the second electrode is disposed on the other side surface of the pyroelectric functional layer, with the surface of the pyroelectric functional layer containing the second electrode being the infrared light incident surface. The second electrode is a single-layer graphene electrode, which is transmissive to infrared light. This invention uses a PVDF vinyl copolymer thin film layer as the pyroelectric functional layer and a single-layer graphene electrode as the electrode on the infrared light incident side. This reduces the thickness of the functional layer and allows it to directly dominate the absorption of infrared radiation, thereby reducing the device's heat capacity. The electrode thickness is also reduced, further reducing the device's heat capacity. Simultaneously, the electrode's absorption of infrared radiation is avoided, thus improving the device's response sensitivity and response speed while maintaining the absorption rate of the pyroelectric functional layer.

[0031] In addition, the present invention also provides a method for preparing a sensitive element structure for an infrared detector and an infrared detector, which also have the above-mentioned beneficial effects. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of an infrared detector sensitive element provided in an embodiment of the present invention;

[0034] Figure 2 This is a curve showing the distribution of energy flux density in the sensitive element structure of an infrared detector.

[0035] Figure 3 A curve showing the distribution of energy flux density in the sensitive element structure of an infrared detector, provided for an embodiment of the present invention;

[0036] Figure 4 A graph showing the absorption rate of an infrared detector sensitive element structure as a function of the thickness of a polyvinylidene fluoride vinyl copolymer film layer, provided in an embodiment of the present invention.

[0037] Figure 5 This is a schematic diagram of another infrared detector sensitive element structure provided in an embodiment of the present invention;

[0038] Figure 6A flowchart illustrating a method for fabricating a sensitive element structure for an infrared detector, provided in an embodiment of the present invention;

[0039] Figure 7 A flowchart illustrating the substrate provided in a method for fabricating a sensitive element structure for an infrared detector according to an embodiment of the present invention.

[0040] Figure 8 A flowchart illustrating the fabrication of a first electrode on the surface of a substrate in a method for fabricating a sensitive element structure of an infrared detector provided in an embodiment of the present invention.

[0041] Figure 9 This is an example flowchart illustrating the preparation of a polyvinylidene fluoride vinyl copolymer thin film layer in a method for preparing a sensitive element structure of an infrared detector provided in an embodiment of the present invention.

[0042] Figure 10 A flowchart illustrating the fabrication process of an infrared detector sensitive element structure provided in an embodiment of the present invention;

[0043] Figure 11 In another method for preparing the sensitive element structure of an infrared detector provided in this embodiment of the invention, a flow chart of a polyvinylidene fluoride vinyl copolymer thin film layer prepared by stretching method is provided.

[0044] Figure 12 A flowchart illustrating the process of preparing a first electrode on a polyvinylidene fluoride vinyl copolymer thin film layer in another method for preparing an infrared detector sensitive element structure provided in an embodiment of the present invention.

[0045] Figure 13 A flowchart illustrating the process of preparing a monolayer graphene electrode on a polyvinylidene fluoride vinyl copolymer thin film layer in another method for preparing a sensitive element structure of an infrared detector provided in an embodiment of the present invention.

[0046] The annotations in the attached figures are explained as follows:

[0047] 1-Infrared light, 10-First electrode, 20-Polyvinylidene fluoride vinyl copolymer thin film layer, 30-Monolayer graphene electrode, 40-Substrate. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] Please refer to Figure 1 , Figure 1 This is a schematic diagram of an infrared detector sensitive element structure provided in an embodiment of the present invention. The infrared detector sensitive element structure may include:

[0050] First electrode 10, pyroelectric functional layer and second electrode; the pyroelectric functional layer is a polyvinylidene fluoride vinyl copolymer film layer 20, which directly absorbs infrared light 1.

[0051] The first electrode 10 is disposed on one side surface of the pyroelectric functional layer, and the second electrode is disposed on the other side surface of the pyroelectric functional layer. The surface of the pyroelectric functional layer on which the second electrode is disposed is the infrared incident surface.

[0052] The second electrode is a single-layer graphene electrode 30; the single-layer graphene electrode 30 is transparent to infrared light 1.

[0053] It should be noted that in this embodiment, the first electrode 10 and the second electrode are respectively disposed on both sides of the pyroelectric functional layer. The second electrode is a monolayer graphene electrode 30, which is positioned on the infrared light 1 incident side of the pyroelectric functional layer. Because the monolayer graphene electrode 30 is extremely thin and the infrared light 1 has low energy, its absorption rate is extremely low when it passes through. Therefore, using monolayer graphene as the electrode on the incident surface of the pyroelectric functional layer in this application achieves extremely low absorption of infrared light 1 due to its thickness and molecular structure. (See reference...) Figure 2 and Figure 3 , Figure 2 This is a curve showing the distribution of energy flux density in the sensitive element structure of an infrared detector. Figure 3 This is a curve showing the distribution of energy flux density in the sensitive element structure of an infrared detector, provided as an embodiment of the present invention. Figure 2 and Figure 3 The horizontal axis represents the distance extended from the infrared light incident surface to the backlight side within the sensitive element structure of the infrared detector. Specifically, in this scheme... Figure 2 A nickel-chromium semi-permeable membrane is used as the second electrode, with its upper surface as the zero point, pointing downwards towards the first electrode. Figure 2 The thickness of the polyvinylidene fluoride vinyl copolymer film layer was set to 3.1 micrometers to achieve the maximum absorption rate of the device. Figure 2 The energy flux density drops to half its original value after passing through the nickel-chromium semi-permeable membrane, indicating that half of the infrared light absorption in the sensitive element structure is accomplished by the nickel-chromium semi-permeable membrane. Therefore, the nickel-chromium semi-permeable membrane needs to conduct the generated heat to the polyvinylidene fluoride vinyl copolymer film layer to generate a sufficiently large signal, which affects the device's performance in high-frequency operating scenarios. Figure 3Using the aforementioned monolayer graphene electrode 30 as the second electrode, and taking the upper surface of the monolayer graphene electrode 30 as the zero point, with the direction pointing downwards towards the first electrode 10, and... Figure 3 The thickness of the polyvinylidene fluoride vinyl copolymer thin film layer 20 is set to 2.3 micrometers to achieve the maximum absorption rate of the device. At this time, in the sensitive element structure, most of the energy flux density change is in the polyvinylidene fluoride vinyl copolymer thin film layer 20, indicating that the absorption of infrared light 1 by the sensitive element structure is mainly completed by the polyvinylidene fluoride vinyl copolymer thin film layer 20, which is suitable for high-frequency working scenarios.

[0054] In another aspect, this application sets the pyroelectric functional layer as a polyvinylidene fluoride (PVDF) vinyl copolymer thin film layer 20. This PVDF vinyl copolymer thin film layer 20 can directly absorb infrared light 1 without the need for an additional infrared absorption layer. Combined with the high transmittance of infrared light 1 by the monolayer graphene electrode 30, the infrared light 1 is basically absorbed by the PVDF vinyl copolymer thin film layer 20. On the one hand, there is no need to set an additional absorption layer to absorb infrared light 1 first and then transfer the resulting heat change to the pyroelectric functional layer to reduce the sensitivity of the reaction. On the other hand, by reducing the thickness of the infrared absorption layer, the heat capacity of the device can be reduced, thereby improving the sensitivity of the device and improving the device performance.

[0055] Furthermore, in order to improve the sensitivity of the device, the thickness of the pyroelectric functional layer can be set to 1 micrometer to 3 micrometers.

[0056] This embodiment can be referred to. Figure 4 , Figure 4 This is a curve showing the absorption rate of an infrared detector sensitive element structure as a function of the thickness of the polyvinylidene fluoride (PVDF) vinyl copolymer film layer, provided in an embodiment of the present invention. It can be seen that when a single-layer graphene electrode 30 is used as the sensitive element structure, the thickness of the PVDF vinyl copolymer film layer 20 corresponding to the maximum absorption rate of the sensitive element structure can be reduced. Figure 4Taking the absorption rate of infrared light 1 with a wavelength of 10 micrometers as an example, the dashed line represents the curve of the absorption rate of the sensitive element structure changing with the thickness of the polyvinylidene fluoride vinyl copolymer film layer when the nickel-chromium semi-permeable membrane is used as the second electrode, and the solid line represents the curve of the absorption rate of the sensitive element structure changing with the thickness of the polyvinylidene fluoride vinyl copolymer film layer 20 when the monolayer graphene electrode 30 is used as the second electrode. At this time, the optimal thickness of the polyvinylidene fluoride vinyl copolymer film layer 20 is 2.3 micrometers. It should be noted that, compared to the thickness of existing pyroelectric functional layers, this embodiment uses a polyvinylidene fluoride (PVDF) vinyl copolymer thin film layer 20 as the pyroelectric functional layer, and sets the electrode of the PVDF vinyl copolymer thin film layer 20 facing the incident side of infrared light 1 as a single-layer graphene electrode 30. In this case, the peak absorption rate of the PVDF vinyl copolymer thin film layer 20 for infrared light 1 is reduced, falling between 1 and 3 micrometers. Therefore, setting the thickness of the PVDF vinyl copolymer thin film layer 20 in this application to 1 to 3 micrometers can reduce the device's heat capacity while ensuring the absorption efficiency of the PVDF vinyl copolymer thin film layer 20 for infrared light 1, thereby improving device performance. Preferably, in this embodiment, the thickness of the PVDF vinyl copolymer thin film layer 20 can be set to 2.3 micrometers. This thickness of the PVDF vinyl copolymer thin film layer 20 can achieve the maximum absorption rate for infrared light 1 with a wavelength of 10 micrometers.

[0057] Furthermore, in order to ensure the conductivity and stability of the device, the first electrode 10 may include at least one of aluminum electrode, gold electrode, silver electrode, platinum electrode, and nickel-chromium electrode.

[0058] In this embodiment, the first electrode 10 is configured to include at least one of aluminum electrode, gold electrode, silver electrode, platinum electrode, and nickel-chromium electrode, which can achieve high conductivity of the device, ensure low contact resistance of the device electrode, and ensure the stability of the device electrode.

[0059] Furthermore, in order to achieve the effects of low resistance and high frequency response of the device, while also taking into account the effect of low stress, the thickness of the first electrode 10 can be set to 50 nanometers to 100 nanometers.

[0060] In this embodiment, by setting the thickness of the first electrode 10 to between 50 nanometers and 100 nanometers, it is possible to ensure low signal loss and delay in the electrode itself, while effectively controlling the internal stress of the metal thin film to ensure the stability of the first electrode 10.

[0061] Furthermore, to improve the ease of preparation of the aforementioned polyvinylidene fluoride vinyl copolymer film layer 20, reference can be made to... Figure 5 , Figure 5This is a schematic diagram of another infrared detector sensitive element structure provided in an embodiment of the present invention. The above-described infrared detector sensitive element structure may also include a substrate 40;

[0062] The substrate 40 is disposed on the side of the first electrode 10 that is opposite to the pyroelectric functional layer.

[0063] It should be noted that in this embodiment, the polyvinylidene fluoride vinyl copolymer film layer 20 is a structure prepared on the substrate 40, which reduces the complexity of preparing the polyvinylidene fluoride vinyl copolymer film layer 20.

[0064] The infrared detector sensitive element structure provided in this embodiment includes a first electrode 10, a pyroelectric functional layer, and a second electrode. The pyroelectric functional layer is a polyvinylidene fluoride (PVDF) vinyl copolymer thin film 20, which directly absorbs infrared light 1. The first electrode 10 is disposed on one side of the pyroelectric functional layer, and the second electrode is disposed on the other side of the pyroelectric functional layer. The surface of the pyroelectric functional layer with the second electrode is the incident surface of infrared light 1. The second electrode is a single-layer graphene electrode 30, which is transmissive to infrared light 1. This invention uses a PVDF vinyl copolymer thin film 20 as the pyroelectric functional layer and a single-layer graphene electrode as the electrode on the infrared light incident side. This reduces the thickness of the functional layer and allows it to directly dominate the absorption of infrared radiation, thereby reducing the device's heat capacity. The electrode thickness is also reduced, further reducing the device's heat capacity. Simultaneously, the electrode's absorption of infrared radiation is avoided, thus improving the device's response sensitivity and response speed while maintaining the absorption rate of the pyroelectric functional layer.

[0065] Furthermore, by setting the thickness of the pyroelectric functional layer to 1 micrometer to 3 micrometers, the sensitivity of the device is improved; by setting the first electrode 10 to include at least one of aluminum, gold, silver, platinum, and nickel-chromium electrodes, the conductivity and stability of the device are ensured; by setting the thickness of the first electrode 10 to 50 nanometers to 100 nanometers, the device achieves low resistance and high frequency response; by setting the infrared detector sensitive element structure to include a substrate 40, and the substrate 40 being formed on the side of the first electrode 10 facing away from the pyroelectric functional layer, the ease of preparation of the polyvinylidene fluoride vinyl copolymer thin film layer 20 is improved.

[0066] The following describes a method for preparing an infrared detector sensitive element structure according to an embodiment of the present invention. The method for preparing the infrared detector sensitive element structure described below can be referred to in correspondence with the infrared detector sensitive element structure described above.

[0067] Please refer to the details. Figure 6 , Figure 6A flowchart of a method for fabricating a sensitive element structure for an infrared detector, provided in an embodiment of the present invention, may include:

[0068] S101: Provide a structure to be processed; the structure to be processed includes at least a polyvinylidene fluoride vinyl copolymer film layer, and a first electrode is prepared on the non-infrared light incident surface of the polyvinylidene fluoride vinyl copolymer film layer; the polyvinylidene fluoride vinyl copolymer film layer directly absorbs infrared light.

[0069] The execution subject of this embodiment is an infrared detector sensitive element structure fabrication system. In this embodiment, the first electrode 10 is used as an electrode of the pyroelectric functional layer.

[0070] Furthermore, this embodiment is applied to the fabrication of sensitive element structures with a substrate, and may include:

[0071] Step S11: Provide a substrate and fabricate a first electrode on the surface of the substrate.

[0072] This step S11 can be referenced. Figure 7 and Figure 8 , Figure 7 This is a flowchart illustrating the substrate provided in a method for fabricating a sensitive element structure for an infrared detector according to an embodiment of the present invention. Figure 8 This is a flowchart illustrating the process of fabricating a first electrode on the surface of a substrate in a method for preparing a sensitive element structure for an infrared detector, as provided in an embodiment of the present invention.

[0073] Step S12: Prepare a polyvinylidene fluoride vinyl copolymer thin film layer on the surface of the first electrode to obtain the structure to be processed.

[0074] In this embodiment, the substrate 40 is used as a support to prepare each functional layer, which simplifies the preparation of the polyvinylidene fluoride vinyl copolymer thin film layer 20. This step S12 can be referred to... Figure 9 , Figure 9 This is a flowchart illustrating the preparation of a polyvinylidene fluoride vinyl copolymer thin film layer in a method for preparing an infrared detector sensitive element structure according to an embodiment of the present invention. Furthermore, the infrared detector sensitive element structure prepared in this embodiment can be referenced from... Figure 10 , Figure 10 This is a flowchart illustrating the fabrication process of an infrared detector sensitive element structure according to an embodiment of the present invention.

[0075] Furthermore, to ensure the successful preparation of the polyvinylidene fluoride vinyl copolymer thin film layer 20, the preparation of the polyvinylidene fluoride vinyl copolymer thin film layer on the surface of the first electrode to obtain the structure to be processed may include:

[0076] A polyvinylidene fluoride vinyl copolymer thin film layer is prepared on the surface of the first electrode 10 using spin coating, casting, or the Langmuir-Braggette method to obtain the structure to be treated.

[0077] In this embodiment, a polyvinylidene fluoride vinyl copolymer thin film layer 20 is prepared on a substrate 40. Specifically, it can be prepared by spin coating, casting, or Langmuir-Braggette method to ensure the ease of preparation of the polyvinylidene fluoride vinyl copolymer thin film layer 20.

[0078] S102: A monolayer graphene electrode is prepared on the infrared light incident surface of a polyvinylidene fluoride vinyl copolymer film layer; the monolayer graphene electrode is transparent to infrared light.

[0079] This embodiment does not limit the specific method of preparing the single-layer graphene electrode 30, as long as it is placed on the infrared incident surface of the above-mentioned polyvinylidene fluoride vinyl copolymer thin film layer 20.

[0080] Furthermore, to ensure the successful fabrication of the aforementioned polyvinylidene fluoride vinyl copolymer thin film layer 20, the fabrication of a monolayer graphene electrode on the infrared light incident surface of the polyvinylidene fluoride vinyl copolymer thin film layer may include:

[0081] Step S21: Prepare a single-layer graphene electrode 30 using mechanical exfoliation or chemical vapor deposition.

[0082] Step S22: Transfer the monolayer graphene electrode 30 to the infrared incident surface of the polyvinylidene fluoride vinyl copolymer film layer using a transfer method.

[0083] In this embodiment, the monolayer graphene electrode 30 can be prepared by mechanical exfoliation or chemical vapor deposition, and then transferred to the surface of the polyvinylidene fluoride vinyl copolymer film layer 20 by a transfer method to ensure that the monolayer graphene electrode 30 film is successfully prepared.

[0084] Furthermore, this embodiment is applied to the fabrication of substrate-free sensitive elemental structures. The aforementioned structure to be processed may include:

[0085] Step S31: Provide a polyvinylidene fluoride vinyl copolymer film layer prepared by a stretching method.

[0086] In this embodiment, the polyvinylidene fluoride vinyl copolymer thin film layer is prepared by stretching, eliminating the need for a substrate for support, thus reducing preparation costs and improving preparation efficiency. Step S31 can be referred to... Figure 11 , Figure 11 The following is a flowchart illustrating the process of preparing a polyvinylidene fluoride vinyl copolymer thin film layer using a stretching method, as provided in another method for preparing an infrared detector sensitive element structure according to an embodiment of the present invention.

[0087] Step S32: Prepare a first electrode on the non-infrared light incident surface of the polyvinylidene fluoride vinyl copolymer thin film to obtain the structure to be processed.

[0088] This step S32 can be referenced. Figure 12 , Figure 12 This is an example flowchart illustrating the process of fabricating a first electrode on a polyvinylidene fluoride vinyl copolymer thin film layer in another method for preparing an infrared detector sensitive element structure according to an embodiment of the present invention. Furthermore, the completed infrared detector sensitive element structure can be referenced from... Figure 13 , Figure 13 This is a flowchart illustrating the process of preparing a monolayer graphene electrode on a polyvinylidene fluoride vinyl copolymer thin film layer in another method for preparing a sensitive element structure of an infrared detector provided in an embodiment of the present invention.

[0089] The method for fabricating the sensitive element structure of an infrared detector provided in this invention includes S101: providing a structure to be processed; the structure to be processed includes at least a polyvinylidene fluoride (PVDF) vinyl copolymer thin film layer, and a first electrode is fabricated on the non-infrared light incident surface of the PVDF vinyl copolymer thin film layer; the PVDF vinyl copolymer thin film layer directly absorbs infrared light; S102: fabricating a monolayer graphene electrode on the infrared light incident surface of the PVDF vinyl copolymer thin film layer; the monolayer graphene electrode is transmissive to infrared light. This invention uses a PVDF vinyl copolymer thin film layer 20 as a pyroelectric functional layer and a monolayer graphene electrode as the electrode on the infrared light incident side. This reduces the thickness of the functional layer and allows it to directly dominate the absorption of infrared light, thereby reducing the device's heat capacity. The electrode thickness is also reduced, further reducing the device's heat capacity. Simultaneously, the electrode's absorption of infrared light is avoided, thus improving the device's response sensitivity and response speed while ensuring the absorption rate of the pyroelectric functional layer.

[0090] Furthermore, in this embodiment of the invention, a polyvinylidene fluoride (PVDF) vinyl copolymer thin film layer 20 is prepared on the surface of the first electrode 10 on the substrate 40 using a substrate 40 as support, which is used to prepare the sensitive element structure with the substrate 40, reducing the complexity of the preparation. The PVDF vinyl copolymer thin film layer 20 is prepared on the surface of the first electrode 10 using spin coating, casting, or Langmuir-Braggette method, and a monolayer graphene electrode 30 is prepared using mechanical exfoliation or chemical vapor deposition. Then, the monolayer graphene electrode 30 is transferred to the infrared incident surface of the PVDF vinyl copolymer thin film layer 20 using a transfer method, ensuring the successful preparation of the PVDF vinyl copolymer thin film layer 20 and the monolayer graphene electrode 30. The PVDF vinyl copolymer thin film layer 20 prepared by stretching method can complete the preparation of the sensitive element structure without the need for a substrate 40, reducing the preparation cost and the thickness of the sensitive element structure.

[0091] The infrared detector provided in the embodiments of the present invention will be described below. The infrared detector described below and the infrared detector sensitive element structure described above can be referred to each other.

[0092] The infrared detector provided in this embodiment of the invention may include the infrared detector sensitive element structure as described above.

[0093] In this embodiment, a single infrared detector may include only one infrared detector sensitive element structure, or it may include multiple infrared detector sensitive element structures as described above.

[0094] The infrared detector provided in this invention includes the infrared detector sensitive element structure as described above. This infrared detector sensitive element structure includes at least a first electrode, a pyroelectric functional layer, and a second electrode. The pyroelectric functional layer is a polyvinylidene fluoride (PVDF) vinyl copolymer thin film layer, which directly absorbs infrared light. The first electrode is disposed on one side surface of the pyroelectric functional layer, and the second electrode is disposed on the other side surface of the pyroelectric functional layer. The surface of the pyroelectric functional layer where the second electrode is disposed is the infrared light incident surface. The second electrode is a single-layer graphene electrode. The single-layer graphene electrode is transmissive to infrared light. This invention uses a PVDF vinyl copolymer thin film layer as the pyroelectric functional layer and a single-layer graphene electrode as the electrode on the infrared light incident side. This reduces the thickness of the functional layer and allows it to directly dominate the absorption of infrared radiation, thereby reducing the device's heat capacity. The electrode thickness is also reduced, further reducing the device's heat capacity. Simultaneously, the electrode's absorption of infrared radiation is avoided. While ensuring the absorption rate of the pyroelectric functional layer, the response sensitivity and response speed of the device are improved.

[0095] The various embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0096] Furthermore, it should be noted that in this document, relationships such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprising," "including," or any other variations are intended to cover non-exclusive inclusion.

[0097] The present invention has provided a detailed description of the sensitive element structure, preparation method, and infrared detector provided by the present invention. Specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation and application scope based on the idea of ​​the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A sensitive element structure for an infrared detector, characterized in that, include: A first electrode, a pyroelectric functional layer, and a second electrode; the pyroelectric functional layer is a polyvinylidene fluoride vinyl copolymer film layer, which directly absorbs infrared light; The first electrode is disposed on one side surface of the pyroelectric functional layer, the second electrode is disposed on the other side surface of the pyroelectric functional layer, and the surface of the pyroelectric functional layer on which the second electrode is disposed is the infrared light incident surface. The second electrode is a single-layer graphene electrode; the single-layer graphene electrode is transparent to infrared light.

2. The infrared detector sensitive element structure according to claim 1, characterized in that, The thickness of the pyroelectric functional layer is 1 micrometer to 3 micrometers.

3. The infrared detector sensitive element structure according to claim 1, characterized in that, The first electrode includes at least one of an aluminum electrode, a gold electrode, a silver electrode, a platinum electrode, and a nickel-chromium electrode.

4. The infrared detector sensitive element structure according to claim 3, characterized in that, The thickness of the first electrode is 50 nanometers to 100 nanometers.

5. The infrared detector sensitive element structure according to claim 1, characterized in that, It also includes the substrate; The substrate is disposed on the side of the first electrode opposite to the pyroelectric functional layer.

6. A method for fabricating a sensitive element structure for an infrared detector, characterized in that, include: A structure to be processed is provided; the structure to be processed includes at least a polyvinylidene fluoride (PVDF) vinyl copolymer film layer, and a first electrode is prepared on the non-infrared light incident surface of the PVDF vinyl copolymer film layer; the PVDF vinyl copolymer film layer directly absorbs infrared light. A monolayer graphene electrode is prepared on the infrared light incident surface of the polyvinylidene fluoride vinyl copolymer film layer; the monolayer graphene electrode is transparent to infrared light.

7. The method for fabricating the sensitive element structure of an infrared detector according to claim 6, characterized in that, Applications in fabricating sensitive elemental structures with substrates, wherein a structure to be processed is provided, comprising: A substrate is provided, and the first electrode is fabricated on the surface of the substrate; A polyvinylidene fluoride vinyl copolymer thin film layer is prepared on the surface of the first electrode to obtain the structure to be processed.

8. The method for fabricating the sensitive element structure of an infrared detector according to claim 6, characterized in that, The preparation of a monolayer graphene electrode on the infrared light incident surface of the polyvinylidene fluoride vinyl copolymer film layer includes: The monolayer graphene electrode was prepared by mechanical exfoliation or chemical vapor deposition. The monolayer graphene electrode was transferred to the infrared light incident surface of the polyvinylidene fluoride vinyl copolymer film using a transfer method.

9. The method for fabricating the sensitive element structure of an infrared detector according to claim 6, characterized in that, The method is applied to the fabrication of substrate-free sensitive metastructures, wherein a structure to be processed is provided, comprising: Provides the polyvinylidene fluoride vinyl copolymer film layer prepared by a stretching method; The first electrode is prepared on the non-infrared light incident surface of the polyvinylidene fluoride vinyl copolymer film layer to obtain the structure to be processed.

10. An infrared detector, characterized in that, Including the infrared detector sensitive element structure as described in any one of claims 1 to 5.

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