Transistor-type photodetector and its manufacturing method

Abstract

The present disclosure provides a transistor-type photodetector, comprising: a first electrode; a second electrode spaced apart from the first electrode; a channel layer disposed at least between the first electrode and the second electrode; a photosensitive layer designed as a p-i-n heterojunction structure, the material of the photosensitive layer being determined by the wavelength band to be detected; and a dielectric layer disposed between the channel layer and the photosensitive layer. The present disclosure also provides a transistor-type photodetector and a method for manufacturing the same.

Description

Technical Field

[0001] The present disclosure relates to a transistor-type photodetector and a method for manufacturing the same. Background Art

[0002] A photodetector is a functional device that converts an optical signal into an electrical signal. According to the wavelength of the detected light, it can be divided into ultraviolet, visible light, infrared, and terahertz detectors. In particular, infrared detectors have important application values in many fields such as military (remote sensing, aiming, night vision, stealth, guidance), aerospace, biological diagnosis, and civilian (automatic driving, infrared lenses for mobile phones, smart homes, wireless sensing, gas monitoring).

[0003] Currently, commercially available photodetectors are based on semiconductor materials such as silicon, germanium, indium gallium arsenide, indium telluride, and mercury cadmium telluride. However, the cut-off wavelength of silicon is short (only 1100 nm), and it can only be used for visible and near-infrared detection. The cut-off wavelength of germanium reaches 1.7 μm, but its performance is poor (indirect bandgap, large dark current, low saturation current), and most of them have been replaced by indium gallium arsenide. Indium gallium arsenide and mercury cadmium telluride need to be epitaxially grown on group III-V, CdTe, or ZnCdTe substrates, with high synthesis difficulty, complex processes, and high costs. Moreover, they are not compatible with silicon-based readout circuits and require heterogeneous bonding with copper pillars or indium pillars, and most of them require additional cooling devices, which results in high prices for current high-performance infrared detectors and chips.

[0004] In order to improve the external quantum efficiency, Photogating-type photodetectors have been designed currently, that is, quantum dots with high absorption coefficients such as PbS and perovskite are used to form type-II heterojunctions with carbon nanotubes, and photo-generated carriers are separated at the interface between the two to form an additional electric field modulation. Such devices can often obtain high gains, but their response and recovery speeds are slow. In 2017, Frank Koppens et al. reported a Photogating-type short-wave infrared detector based on graphene / PbS quantum dots and its 288×388 pixel-scale focal plane image sensor. The responsivity of the device is as high as 10 7 A / W, and the specific detectivity is up to 7×10 13 Jones, but there are problems such as slow speed (response time of 10 ms, and gate voltage pulses are required to force recovery), small dynamic range, and low on-off ratio. In 2021, Sun Dongming et al. from the Institute of Metal Research, Chinese Academy of Sciences, used CsPbBr3 and carbon nanotubes to construct a Photogating-type photodetector. The responsivity to visible light at 405 and 516 nm reached 10 7 A / W, and D* reached 10 16 Jones, but the response time is in the range of dozens of ms-s, and additional gate voltage pulses are still required to force the detector to return to the baseline.

[0005] In addition, with the development of carbon nanotube technology, carbon nanotubes are gradually used in devices. However, practical photodetectors have not been developed in the field of optoelectronic detection such as infrared yet. The main reasons are as follows: 1. The light absorption of single-walled or thin-film carbon nanotubes is limited, and the external quantum efficiency is low; 2. BFBD is an ideal carbon nanotube diode architecture, but the built-in electric field is only in the region of about 50 nm near the source-drain contact. Due to the diffraction limit, the pixel size of infrared detectors is mostly larger than 1 μm. Therefore, it is difficult for BFBD devices to obtain a high signal-to-noise ratio; 3. The Photogating structure is an important way to overcome the low quantum efficiency and the small range of the built-in electric field. However, under the current Photogating device architecture, the performance of photodetectors is poor, and there is a contradiction between the responsivity / external quantum efficiency and the speed.

[0006] Therefore, how to design a new photodetector structure to break through the current dilemma is the problem to be solved. Summary of the Invention

[0007] In order to solve one of the above technical problems, the present disclosure provides a transistor-type photodetector and a preparation method thereof. According to the technical solution of the present disclosure, a faster response speed, a higher responsivity / external quantum efficiency, and a larger signal-to-noise ratio can be obtained.

[0008] According to one aspect of the present disclosure, a transistor-type photodetector includes:

[0009] A first electrode;

[0010] A second electrode, the second electrode being spaced apart from the first electrode;

[0011] A channel layer, the channel layer being disposed at least between the first electrode and the second electrode;

[0012] A photosensitive layer, the photosensitive layer being designed as a p-i-n heterojunction structure, and the material of the photosensitive layer being determined by the wavelength band to be detected; and

[0013] A dielectric layer, the dielectric layer being disposed between the channel layer and the photosensitive layer.

[0014] In the transistor-type photodetector according to at least one embodiment of the present disclosure, the dielectric layer is used to apply the change of the electric field signal of the built-in electric field of the photosensitive layer to the channel layer in a capacitive coupling manner.

[0015] In the transistor-type photodetector according to at least one embodiment of the present disclosure, the dielectric layer is a high-k dielectric layer.

[0016] The transistor-type photodetector according to at least one embodiment of the present disclosure further includes: a gate and a gate insulating layer, and the gate insulating layer is disposed between the channel layer and the gate.

[0017] The transistor-type photodetector according to at least one embodiment of the present disclosure, the transistor-type photodetector is configured as a global bottom-gate structure, and the substrate in the global bottom-gate structure is a doped substrate and serves as the gate; or

[0018] The transistor-type photodetector is configured as a local bottom-gate structure, wherein the local bottom-gate structure includes a substrate, and the gate is formed in the substrate.

[0019] The transistor-type photodetector according to at least one embodiment of the present disclosure, the transistor-type photodetector is configured as a top-gate structure, in the top-gate structure includes a substrate, the substrate is a transparent substrate and is disposed under the photosensitive layer, and the gate insulating layer is disposed above the channel layer.

[0020] The transistor-type photodetector according to at least one embodiment of the present disclosure, a functional layer is designed outside the photosensitive layer, and the functional layer is at least one of a filter layer, an antireflection film, and a packaging layer.

[0021] The transistor-type photodetector according to at least one embodiment of the present disclosure, a functional layer is designed between the p-i junction and the i-n in the p-i-n heterojunction structure of the photosensitive layer, and the functional layer is used to achieve energy band matching or improve mechanical and electrical stability.

[0022] The transistor-type photodetector according to at least one embodiment of the present disclosure, a first functional layer is designed between the substrate and the photosensitive layer, and the first functional layer is at least one of a filter layer, an antireflection film, and a passivation layer; and / or

[0023] A second functional layer is designed between the photosensitive layer and the dielectric layer, and the second functional layer is used to adjust the threshold voltage of the transistor-type photodetector.

[0024] The transistor-type photodetector according to at least one embodiment of the present disclosure, the dielectric layer is a single-layer dielectric layer made of a high dielectric constant material or two or more dielectric layers made of different high dielectric constant materials.

[0025] According to another aspect of the present disclosure, a transistor-type photodetector includes:

[0026] A first electrode;

[0027] A second electrode, the second electrode being spaced apart from the first electrode;

[0028] A carbon nanotube channel layer, which is disposed at least between the first electrode and the second electrode;

[0029] A photosensitive layer, which is designed as one of a p-i-n heterojunction, a p-n inverse heterojunction, an n-n homojunction, a p-p homojunction, an n-p-n double heterojunction, a p-n-p double heterojunction, and a Schottky junction, and the material of the photosensitive layer is determined by the wavelength band to be detected; and

[0030] A dielectric layer, which is disposed between the carbon nanotube channel layer and the photosensitive layer.

[0031] For the transistor-type photodetector according to at least one embodiment of the present disclosure, the dielectric layer is configured to apply the change in the electric field signal of the built-in electric field of the photosensitive layer to the carbon nanotube channel layer in a capacitive coupling manner.

[0032] For the transistor-type photodetector according to at least one embodiment of the present disclosure, the dielectric layer is a high-k dielectric layer.

[0033] For the transistor-type photodetector according to at least one embodiment of the present disclosure, it further includes: a gate and a gate insulating layer, and the gate insulating layer is disposed between the carbon nanotube channel layer and the gate.

[0034] For the transistor-type photodetector according to at least one embodiment of the present disclosure, the transistor-type photodetector is configured as a global bottom-gate structure, and the substrate in the global bottom-gate structure is a doped substrate and serves as the gate; or

[0035] The transistor-type photodetector is configured as a local bottom-gate structure, and the local bottom-gate structure includes a substrate, and the gate is formed in the substrate.

[0036] For the transistor-type photodetector according to at least one embodiment of the present disclosure, the transistor-type photodetector is configured as a top-gate structure. In the top-gate structure, there is a substrate, the substrate is a transparent substrate and is disposed under the photosensitive layer, and the gate insulating layer is disposed above the carbon nanotube channel layer.

[0037] For the transistor-type photodetector according to at least one embodiment of the present disclosure, a functional layer is designed on the outside of the photosensitive layer, and the functional layer is at least one of a filter layer, an antireflection film, and a packaging layer.

[0038] For the transistor-type photodetector according to at least one embodiment of the present disclosure, a functional layer is designed between the junction structures of the photosensitive layer, and the functional layer is used to achieve band alignment or improve mechanical and electrical stability.

[0039] A transistor-type photodetector according to at least one embodiment of the present disclosure, a first functional layer is designed between the substrate and the photosensitive layer, and the first functional layer is at least one of a filter layer, an antireflection film, and a passivation layer; and / or

[0040] A second functional layer is designed between the photosensitive layer and the dielectric layer, and the second functional layer is used to adjust the threshold voltage of the transistor-type photodetector.

[0041] A transistor-type photodetector according to at least one embodiment of the present disclosure, the dielectric layer is a single-layer dielectric layer made of a high dielectric constant material or two or more dielectric layers made of different high dielectric constant materials.

[0042] According to another aspect of the present disclosure, a method for manufacturing a transistor-type photodetector includes:

[0043] Preparing a gate insulating layer on a doped substrate, wherein the substrate serves as a gate;

[0044] Preparing a channel layer on the gate insulating layer;

[0045] Preparing a first electrode and a second electrode;

[0046] Preparing a high dielectric constant material on the channel layer to form a dielectric layer; and

[0047] Preparing a photosensitive layer on the dielectric layer.

[0048] According to another aspect of the present disclosure, a method for manufacturing a transistor-type photodetector includes:

[0049] Preparing a gate in a substrate;

[0050] Preparing a gate insulating layer on the substrate and the gate;

[0051] Preparing a channel layer on the gate insulating layer;

[0052] Preparing a first electrode and a second electrode;

[0053] Preparing a high dielectric constant material on the channel layer to form a dielectric layer; and

[0054] Preparing a photosensitive layer on the dielectric layer.

[0055] According to another aspect of the present disclosure, a method for manufacturing a transistor-type photodetector includes:

[0056] Preparing a photosensitive layer on a transparent substrate;

[0057] Preparing a high dielectric constant material on the photosensitive layer to form a dielectric layer;

[0058] Fabricate a channel layer over the dielectric layer;

[0059] Fabricate a first electrode and a second electrode;

[0060] Fabricate at least a gate insulating layer over the channel layer; and

[0061] Fabricate a gate over the gate insulation.

[0062] According to the preparation method of at least one embodiment of the present disclosure, the photosensitive layer is a p-i-n heterojunction structure, and the material of the photosensitive layer is determined by the wavelength band to be detected.

[0063] According to the preparation method of at least one embodiment of the present disclosure, the channel layer is a carbon nanotube channel layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] The drawings illustrate exemplary embodiments of the present disclosure and, together with the description thereof, are used to explain the principles of the present disclosure. These drawings are included to provide a further understanding of the present disclosure and are incorporated in this specification and form a part of this specification.

[0065] Figure 1 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

[0066] Figure 2 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

[0067] Figure 3 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

[0068] Figure 4 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

[0069] Figure 5 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

[0070] Figure 6 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

[0071] Figure 7 is a flowchart of a preparation method according to an embodiment of the present disclosure.

[0072] Figure 8 is a flowchart of a preparation method according to an embodiment of the present disclosure.

[0073] Figure 9 is a flowchart of a preparation method according to an embodiment of the present disclosure.

[0074] Figure 10It is a flowchart of a preparation method according to an embodiment of the present disclosure.

[0075] Figure 11 It is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

[0076] Figures 12 to 16 It is a schematic diagram of the performance index of a photodetector according to an embodiment of the present disclosure. Detailed Embodiments

[0077] The present disclosure will be further described in detail below in conjunction with the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the relevant content and do not limit the present disclosure. Additionally, it should be noted that for the sake of description, only parts related to the present disclosure are shown in the drawings.

[0078] It should be noted that, without conflict, the embodiments in the present disclosure and the features in the embodiments can be combined with each other. The technical solutions of the present disclosure will be described in detail below with reference to the accompanying drawings and embodiments.

[0079] Unless otherwise specified, the exemplary embodiments / Examples shown will be understood to provide exemplary features of various details of some ways in which the technical concept of the present disclosure can be implemented in practice. Therefore, unless otherwise specified, without departing from the technical concept of the present disclosure, the features of various embodiments / Examples can be additionally combined, separated, interchanged, and / or rearranged.

[0080] In the drawings, cross-hatching and / or shading are generally used to make the boundaries between adjacent components clear. Thus, unless stated, the presence or absence of cross-hatching or shading does not convey or imply any preference or requirement for the specific materials, material properties, dimensions, proportions, commonalities between the components shown, and / or any other characteristics, attributes, properties, etc. of the components. Additionally, in the drawings, for clarity and / or descriptive purposes, the dimensions and relative dimensions of the components may be exaggerated. When the exemplary embodiments can be implemented differently, the specific process sequences can be executed in an order different from that described. For example, two consecutively described processes can be executed substantially simultaneously or in an order opposite to that described. Moreover, the same reference numerals denote the same components.

[0081] When a component is referred to as being "on" or "above" another component, "connected to" or "coupled to" another component, the component can be directly on the other component, directly connected to or directly coupled to the other component, or there can be intermediate components. However, when a component is referred to as being "directly on" another component, "directly connected to" or "directly coupled to" another component, there are no intermediate components. For this reason, the term "connected" can refer to a physical connection, an electrical connection, etc., and can have or not have intermediate components.

[0082] For convenience, in the following description, various device geometries according to embodiments of the present invention are described with respect to the device in the orientation shown in the drawings. In cases where terms such as "above", "over", "lateral", "vertical", etc. are used in the description, these should not be construed to mean that such embodiments are limited to the specific directions shown in the drawings. It should be readily understood that the devices described herein will be able to operate correctly regardless of the physical orientation of the device or the physical orientation of the apparatus including the device, and thus the following description should be interpreted accordingly. Additionally, a transistor according to an embodiment of the present invention includes a semiconductor region, which can include a semiconductor, a semimetal, or a degenerately doped semiconductor, or a combination thereof. Accordingly, references to "semiconductor region" in this document should be interpreted accordingly.

[0083] The terms used herein are for the purpose of describing particular embodiments and are not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are also intended to include the plural forms. Additionally, when the terms "comprises" and / or "comprising" and their variants are used in this specification, it is stated that there are the stated features, integers, steps, operations, components, assemblies, and / or groups thereof, but there is no exclusion of the presence or addition of one or more other features, integers, steps, operations, components, assemblies, and / or groups thereof. It should also be noted that, as used herein, the terms "substantially", "about", and other similar terms are used as approximate terms and not as terms of degree, and thus they are used to explain the inherent deviations of measured, calculated, and / or provided values that would be recognized by a person of ordinary skill in the art.

[0084] According to an embodiment of the present disclosure, there is provided a transistor-type photodetector, where the transistor-type photodetector can be an infrared detector, a visible light detector, an ultraviolet detector, a terahertz detector, and so on.

[0085] Figure 1 A schematic diagram of a transistor-type photodetector according to an embodiment of the present disclosure is shown.

[0086] As Figure 1As shown, the photodetector 10 may include a first electrode 110 and a second electrode 120. The first electrode 110 and the second electrode 120 may be spaced apart from each other, where the first electrode 110 may be a source or a drain, and the second electrode 120 may be a drain or a source. A channel layer 130 may be disposed between the first electrode 110 and the second electrode 120.

[0087] The first electrode 110 and the second electrode 120 may be formed of any suitable material or combination of materials. Examples of materials that can be used for the first electrode 110 and the second electrode 120 include, but are not limited to: metals, conductive or semiconductor metal oxides, conductive or semiconductor polymers, doped semiconductors, graphene, and two-dimensional (2D) semiconductors, etc. As a preferred example, the materials of the first electrode 110 and the second electrode 120 may be one or more of metal materials such as Ti (titanium), Pd (palladium), or Au (gold).

[0088] The photodetector 10 may include a channel layer 130. The channel layer 130 is at least disposed in the region between the first electrode 110 and the second electrode 120. Examples of materials that can be used for the channel layer 130 include, but are not limited to: crystalline or amorphous silicon, semiconductor metal oxides, transition metal chalcogenides, graphene, carbon nanotubes, semiconductor nanowires, organic semiconductors, and other two-dimensional materials.

[0089] In the present disclosure, the material of the channel layer 130 is preferably carbon nanotubes. For example, a network-shaped or aligned high-purity carbon nanotube film may be deposited on a wafer. In addition, the density of the carbon nanotubes can also be controlled according to actual needs.

[0090] In addition, after the deposition of the two-dimensional material is completed, the two-dimensional material outside the channel region can be etched to avoid electrical crosstalk between devices.

[0091] The photodetector 10 may include a dielectric layer 140. The dielectric layer 140 may be disposed between the channel layer 130 and the photosensitive layer 150 described below. The dielectric layer 140 may be an insulating dielectric. Examples of materials that can be used for the dielectric layer 140 include, but are not limited to: any one of SiO2, HfO2, ZrO2, Ta2O5, Y2O3, Nb2O5, Al2O3, TiO2, CeO2, In2O3, RuO2, MgO, SrO, B2O3, SnO2, PbO, PbO2, Pb3O4, V2O3, La2O3, Pr2O3, Sb2O3, Sb2O5, CaO, etc. In the present disclosure, the dielectric layer 140 may be a single-layer structure formed of the materials listed above. However, the dielectric layer 140 may also be a structure of two or more layers, such as a multilayer structure formed of different materials listed above. The dielectric layer 140 can be prepared by processes such as exposure, thermal oxidation, or ALD.

[0092] In the present disclosure, the dielectric layer 140 is preferably a high-k dielectric layer. Through the design of this dielectric layer 140, the change in the electric field signal of the built-in electric field of the photosensitive layer 150 can be amplified in a capacitive coupling manner and applied to the channel layer 130. According to the unique device structure of the present disclosure, the effective amplification of the optical signal (optical voltage) can be achieved in a capacitive coupling manner, so that a higher responsivity / external quantum efficiency can be obtained. In the structure of the present disclosure, the photo-generated excitons do not need to be completely separated, and only an electric dipole potential needs to be generated, that is, a potential distribution needs to be generated. Therefore, the photodetector of the present disclosure can have an extremely fast response speed. Therefore, according to the device structure of the present disclosure, the disadvantages of the traditional Photogating type photodetector, in which it is difficult to achieve both high responsivity and speed, can be solved, and the problems such as the contact between the photosensitive layer material and the channel layer material, the influence of the photosensitive layer material on the transport characteristics of the channel layer material, and the complication of the sensing mechanism can also be well solved.

[0093] The photodetector 10 may include a photosensitive layer 150. The photosensitive layer 150 is disposed adjacent to the dielectric layer 140. The material of the photosensitive layer 150 is determined by the wavelength band to be detected. The photosensitive layer 150 can be designed into junction structures such as p-i-n heterojunctions, p-n inverse heterojunctions, n-n homojunctions, p-p homojunctions, n-p-n double heterojunctions, p-n-p double heterojunctions, Schottky junctions, etc. In the present disclosure, preferably, the photosensitive layer 150 can be designed into a p-i-n heterojunction. In the junction structure of this p-i-n heterojunction, the p-region and the n-region can be set to be relatively thin, and the i-region can be set to be relatively thick, that is, the set thickness of the i-region is greater than the set thickness of the p-region and the n-region. Through this setting, the tunneling effect of majority carriers can be effectively suppressed, and it has high sensitivity, small junction capacitance, small circuit constants, wide depletion layer, short diffusion and transit times, and fast response speed.

[0094] In the present disclosure, the photosensitive layer 150 can be formed in the following manner. As an example, an amorphous or polycrystalline thin film prepared by methods such as thermal evaporation, magnetron sputtering, electron beam evaporation, atomic layer deposition, chemical vapor deposition, etc., such as ZnO, TiO2, Si, PbS, PbSe, etc. thin films, can be used to form the photosensitive layer 150. As another example, a polycrystalline or single-crystalline colloidal quantum dot thin film can be used to form the photosensitive layer 150, such as quantum dot systems including Pb-based, Hg-based, Cd-based, Si, oxides, perovskites, etc., such as PbS, PbSe, HgTe, Si, CdTe, CdS, ZnO and their core-shell structure quantum dots. As still another example, a thin film composed of single-crystalline or polycrystalline nanowires, nanosheets, etc. can be used to form the photosensitive layer 150, such as GaAs, Te and other nanowires and ZnO, HgTe and other nanosheets.

[0095] For example, when the transistor-type photodetector is a mid-wave infrared detector, the p-i-n junction of the photosensitive layer 150 can be Ag2Te-HgTe-Bi2Se3. When the transistor-type photodetector is a short-wave infrared detector, the p-i-n junction of the photosensitive layer 150 can be p-i-nGeSn, p-Si / i-Ge / n-Ge, PbS-EDT quantum dots / i-halogen framework PbS quantum dots / n-ZnO, or n-TiO2. When the transistor-type photodetector is a near-infrared wave detector, the p-i-n junction of the photosensitive layer 150 can be p-NiOx / i-halogen framework PbS quantum dots / n-ZnO. When the transistor-type photodetector is a visible light detector, the p-i-n junction of the photosensitive layer 150 can be a p-i-n silicon heterojunction. When the transistor-type photodetector is an ultraviolet light detector, the p-i-n junction of the photosensitive layer 150 can be a ZnO thin film, a p-i-n heterojunction of p-Si / i-ZnO / n-ZnO.

[0096] In addition, for the p-i-n junction structure, a functional layer can be designed between p-i or i-n to better achieve energy band matching, or improve mechanical and / or electrical stability, etc. For example, a p-NiOx / i-PbS quantum dots / C60 / n-ZnO structure can be designed as the photosensitive layer for near-infrared detection, where C60 serves as the functional layer; a p-Si / SiOx / i-ZnO / n-ZnO can be designed as the photosensitive layer for ultraviolet photodetection, where SiOx serves as the functional layer.

[0097] In the structure of the present disclosure, the action range of the built-in electric field can be formed in the region of the entire junction structure, thus well solving the problem of the limited action range of the built-in electric field of the BFBD device. In the BFBD device, the action range of the built-in electric field is only in the region of about 50 nm near the source-drain contact, so it is difficult for the BFBD device to obtain a high signal-to-noise ratio.

[0098] The photodetector 10 may include a gate insulating layer 160. The gate insulating layer 160 can be any insulating medium, for example, it can be SiO2. Figure 1 The global bottom gate structure is shown. In this global bottom gate structure, the doped substrate 170 can serve as the gate, and the gate insulating layer 160 can be disposed between the substrate 170 and the channel layer 130.

[0099] Figure 2 Another embodiment according to the present disclosure is shown. The difference between this embodiment and the content described with reference to Figure 1 is that a functional layer 180 can be disposed outside the photosensitive layer 150, where the functional layer 180 can be a single-layer structure or a multi-layer structure, for example, it can be at least one of a filter layer, an antireflection film, a packaging layer, etc. ForFigure 1 The content that is the same as the relevant description will not be elaborated here.

[0100] Figure 3 FIG. shows a schematic diagram of a transistor-type photodetector 20 according to another embodiment of the present disclosure. In this embodiment, the photodetector 20 may include a first electrode 210, a second electrode 220, a channel layer 230, a dielectric layer 240, a photosensitive layer 250, a gate insulating layer 260, a substrate 270, and a gate 280.

[0101] Among them, the specific descriptions of the first electrode 210, the second electrode 220, the channel layer 230, the dielectric layer 240, the photosensitive layer 250, and the gate insulating layer 260 may refer to the detailed descriptions of the first electrode 110, the second electrode 120, the channel layer 130, the dielectric layer 140, the photosensitive layer 150, and the gate insulating layer 160. For the sake of brevity, they will not be elaborated here.

[0102] Figure 3 The embodiment of Figure 1 The main difference from the embodiment of Figure 3 is that a local bottom-gate structure is adopted in Figure 1 while a global bottom-gate structure is adopted in

[0103] In Figure 3 's embodiment, the gate 280 can be made of metal materials such as Ti, Al, Sc, Ni, Pd, Au, Pt, etc., or can be a stacked structure of metal materials. In the present disclosure, the gate metal can be selected to achieve the regulation of the threshold of the transistor. By regulating the voltage applied to the bottom-gate metal, the transistor can be biased at the optimal operating point to achieve the best signal-to-noise ratio.

[0104] In the present disclosure, the substrate material can be silicon, glass, quartz, ITO, etc.; or flexible substrates such as flexible PI, PET, etc.

[0105] In Figure 3 's embodiment, a functional layer (such as Figure 2 's description) can also be provided on the photosensitive layer 250, where the functional layer can be a single-layer structure or a multi-layer structure, and can be at least one of, for example, a filter layer, an antireflection film, a packaging layer, etc.

[0106] Figure 4 FIG. shows a schematic diagram of a transistor-type photodetector 30 according to yet another embodiment of the present disclosure. Figure 4The transistor-type photodetector 30 shown may be a back-incident photodetector of a top-gate structure. In the photodetector of this embodiment, a first electrode 310, a second electrode 320, a channel layer 330, a dielectric layer 340, a photosensitive layer 350, a gate insulating layer 360, a substrate 370 and a gate 380 may be included. The specific description of these parts may refer to the above description, and will not be repeated here.

[0107] In the present disclosure, the photosensitive layer 350 may be disposed on a substrate 370. The substrate 370 may be provided in a transparent form (eg, made of glass, quartz, ITO, etc.) so that light can be transmitted from the substrate 370. Figure 4 The lower portion of the substrate 370 shown enters and irradiates the photosensitive layer 350. A dielectric layer 340 may be disposed on the photosensitive layer 350. The channel layer 330 is formed between the first electrode 310 and the second electrode 320, and is located between the gate insulating layer 360 and the channel layer 330.

[0108] According to a further embodiment of the present disclosure, Figure 5 As shown, the transistor-type photodetector 30 may further include a first functional layer 391, wherein the first functional layer 391 may be at least one of a filter layer, an anti-reflection film, a passivation layer, etc. The first functional layer 391 may be disposed between the photosensitive layer 350 and the transparent substrate 370. In addition, the transistor-type photodetector 30 may further include a second functional layer 392. The second functional layer 392 may be disposed between the photosensitive layer 350 and the dielectric layer 340, and the second functional layer 392 may be used to adjust the threshold voltage of the transistor-type photodetector, for example, the second functional layer 392 may be a metal layer, and may also be an anti-reflection film, etc.

[0109] According to the device structure disclosed in the present invention, the gate voltage of the transistor photodetector can be adjusted to bias its channel layer to the optimal operating point to achieve the best signal-to-noise ratio. Figure 6 After the circuit is connected as shown, the gate voltage V can be adjusted. GS , so that the channel layer is biased to the optimal operating point, thereby achieving the best signal-to-noise ratio.

[0110] According to the technical solution disclosed in the present invention, the problem that the built-in electric field of the BFBD device has a limited range of action and is difficult to obtain a high signal-to-noise ratio can be effectively solved, and the contradiction between the responsivity / external quantum efficiency and speed of the Photogating type device can also be well solved.

[0111] Particularly, in the case where the channel layer is made of carbon nanotube material, the technical solution of the present disclosure can simultaneously achieve a relatively fast response speed, a relatively high responsivity / external quantum efficiency, and a relatively large signal-to-noise ratio. Specifically: deposit network-shaped or array carbon nanotubes on a wafer to realize batch production of high-quality bottom-gate transistors. Since carbon nanotubes have excellent charge transport properties, rapid carrier transport can be achieved. Deposit a high-k dielectric on the carbon nanotubes by means of ALD, thermal oxidation, etc. as the dielectric layer. The design of this dielectric layer can amplify the change of the electric field signal by means of capacitive coupling and act on the carbon nanotubes; deposit a quantum thin film, etc. as the photosensitive layer on the dielectric layer by means of spin coating, sputtering, etc., which has a high external quantum efficiency and can achieve effective light absorption; design p-i-n heterojunctions, p-n inverse heterojunctions, n-n homojunctions, p-p homojunctions, n-p-n double heterojunctions, p-n-p double heterojunctions, Schottky junctions in the photosensitive layer to achieve effective and rapid separation of photo-generated carriers and form a photo-voltage; by regulating the gate voltage applied to the carbon nanotube bottom-gate transistor, bias the carbon nanotubes at the optimal operating point to achieve the optimal signal-to-noise ratio.

[0112] According to another embodiment of the present disclosure, a method for manufacturing a transistor-type photodetector is provided. Figure 7 A flowchart of a manufacturing method M700 according to an embodiment of the present disclosure is shown and may include the following.

[0113] In step S702, a photosensitive layer or a channel layer is prepared; in step S704, a dielectric layer is prepared, and in step S706, a channel layer or a photosensitive layer is prepared. If the photosensitive layer is prepared in step S702, the channel layer is prepared in step S706, and if the channel layer is prepared in step S702, the photosensitive layer is prepared in step S706. The photosensitive layer has a p-i-n heterojunction structure, and the material of the photosensitive layer is determined by the wavelength band to be detected. Alternatively, the channel layer is a carbon nanotube channel layer.

[0114] According to a specific embodiment of the present disclosure, the following method for manufacturing a transistor-type photodetector is provided, where in the following description, carbon nanotubes are used as the channel layer for description.

[0115] Figure 8 A flowchart of a specific manufacturing method M800 is shown. Method M800 may correspond to the global bottom-gate structure of the embodiment as Figure 1 described, and the specific content of this method may refer to the description of Figure 1 the embodiment.

[0116] In step S802, a gate insulating layer may be deposited on the wafer. The gate insulating layer may be any insulating medium, and the wafer may be a doped substrate and may be used as the gate of the transistor-type photodetector.

[0117] In step S804, a channel layer may be deposited on the gate insulating layer. For example, a network-shaped or aligned high-purity carbon nanotube thin film may be deposited. As described above, other two-dimensional materials such as crystalline or amorphous silicon, semiconductor metal oxides, transition metal chalcogenides, graphene, semiconductor nanowires, and organic semiconductors may also be used for deposition to form the channel layer. In the present disclosure, the density of the deposited carbon nanotubes can be correspondingly controlled. In addition, after the carbon nanotube deposition is completed, high-temperature annealing may be performed, and an organic polymer on the surface of the carbon nanotubes may be removed by using, for example, a yttrium oxide cleaning technique.

[0118] In step S806, the first electrode and the second electrode may be prepared. Specifically, microfabrication processes such as exposure and electron beam coating may be used to deposit a metal material to prepare the first electrode and the second electrode. The materials of the first electrode and the second electrode may be one or more of metal materials such as Ti, Pd, or Au.

[0119] In step S808, processes such as exposure and dry etching may be used to pattern the carbon nanotube thin film, and the carbon nanotubes outside the channel region may be etched to avoid electrical crosstalk between devices.

[0120] In step S810, a dielectric layer may be formed on the carbon nanotube thin film, and the material of the dielectric layer may be as described above. For example, electron beam evaporation of yttrium metal may be used, followed by thermal oxidation, to form yttrium oxide on the carbon nanotube thin film as a high dielectric constant dielectric layer. In addition, a multi-layer structure of oxides may also be formed to form a high dielectric constant dielectric layer.

[0121] In step S812, a photosensitive layer may be prepared on the dielectric layer. The photosensitive layer may be prepared into a two-layer to three-layer structure, and the material of the photosensitive layer is determined according to the desired detection wavelength band. And the photosensitive layer is prepared to promote the effective separation of photo-generated carriers. The photosensitive layer may be prepared into junction structures such as p-i-n heterojunctions, p-n inverse heterojunctions, n-n homojunctions, p-p homojunctions, n-p-n double heterojunctions, p-n-p double heterojunctions, and Schottky junctions.

[0122] In the present disclosure, the photosensitive layer is preferably a p-i-n heterojunction. For example, in the case of mid-wave infrared detection, the p-i-n junction of the photosensitive layer can be Ag2Te-HgTe-Bi2Se3. When the transistor-type photodetector is a short-wave infrared detector, the p-i-n junction of the photosensitive layer can be p-i-n GeSn, p-Si / i-Ge / n-Ge, p-PbS-EDT quantum dots / i-halogen framework PbS quantum dots / n-ZnO or n-TiO2. When the transistor-type photodetector is a near-infrared wave detector, the p-i-n junction of the photosensitive layer can be p-NiOx / i-halogen framework PbS quantum dots / n-ZnO. When the transistor-type photodetector is a visible light detector, the p-i-n junction of the photosensitive layer can be a p-i-n silicon heterojunction. When the transistor-type photodetector is an ultraviolet light detector, the p-i-n junction of the photosensitive layer can be a ZnO thin film, a p-i-n heterojunction of p-Si / i-ZnO / n-ZnO.

[0123] In this embodiment, one or more functional layers may also be prepared on the photosensitive layer, for example, at least one of a filter layer, an antireflection film, a packaging layer, etc. Further, it may also include performing circuit connections as shown in Figure 6 to perform corresponding optoelectronic performance tests, and obtaining the best signal-to-noise ratio by adjusting the bottom gate operating voltage.

[0124] Figure 9 The flowchart of a specific preparation method M900 is shown. The method M900 may correspond to the local bottom gate structure of the embodiment as shown in Figure 3 and the specific content of this method can be referred to the description of Figure 3

[0125] In step S902, a gate structure is processed on the wafer, and gate metal is deposited to prepare the gate.

[0126] In step S904, a gate insulating layer may be deposited on the wafer and the gate structure. The gate insulating layer can be any insulating medium.

[0127] In step S906, a channel layer may be deposited on the gate insulating layer, for example, a network-shaped or aligned high-purity carbon nanotube thin film may be deposited. As described above, other two-dimensional materials such as crystalline or amorphous silicon, semiconductor metal oxides, transition metal chalcogenides, graphene, semiconductor nanowires, organic semiconductors, etc. may also be used for deposition to form the channel layer. In the present disclosure, the density of the deposited carbon nanotubes can be controlled accordingly. In addition, after the carbon nanotubes are deposited, high-temperature annealing may be performed, and an organic polymer on the surface of the carbon nanotubes may be removed by using, for example, a yttrium oxide cleaning technique.

[0128] In step S908, the first electrode and the second electrode can be fabricated. Microfabrication processes such as exposure and electron beam coating can be used to deposit metal materials to fabricate the first electrode and the second electrode. The materials of the first electrode and the second electrode can be one or more of metal materials such as Ti, Pd, or Au.

[0129] In step S910, processes such as exposure and dry etching can be used to pattern the carbon nanotube film, and the carbon nanotubes outside the channel region are etched to avoid electrical crosstalk between devices.

[0130] In step S912, a dielectric layer can be formed on the carbon nanotube film, and the material of the dielectric layer can be as described above. For example, electron beam evaporation of yttrium metal can be used, followed by thermal oxidation, to form yttrium oxide on the carbon nanotube film as a high dielectric constant dielectric layer. In addition, a multi-layer structure of oxides can also be formed to form a high dielectric constant dielectric layer.

[0131] In step S914, a photosensitive layer can be fabricated on the dielectric layer. The photosensitive layer can be fabricated into a two-layer to three-layer structure, and the material of the photosensitive layer is determined according to the required detection wavelength band. And the photosensitive layer is fabricated to promote the effective separation of photo-generated carriers. The photosensitive layer can be fabricated into junction structures such as p-i-n heterojunction, p-n inverse heterojunction, n-n homojunction, p-p homojunction, n-p-n double heterojunction, p-n-p double heterojunction, Schottky junction, etc.

[0132] In the present disclosure, the photosensitive layer is preferably a p-i-n heterojunction. For example, in the case of mid-wave infrared detection, the p-i-n junction of the photosensitive layer can be Ag2Te-HgTe-Bi2Se3. When the transistor-type photodetector is a short-wave infrared detector, the p-i-n junction of the photosensitive layer can be p-i-n GeSn, p-Si / i-Ge / n-Ge, p-PbS-EDT quantum dots / i-halogen framework PbS quantum dots / n-ZnO or n-TiO2. When the transistor-type photodetector is a near-infrared wave detector, the p-i-n junction of the photosensitive layer can be p-NiOx / i-halogen framework PbS quantum dots / n-ZnO. When the transistor-type photodetector is a visible light detector, the p-i-n junction of the photosensitive layer can be a p-i-n silicon heterojunction. When the transistor-type photodetector is an ultraviolet light detector, the p-i-n junction of the photosensitive layer can be a ZnO film, a p-i-n heterojunction of p-Si / i-ZnO / n-ZnO.

[0133] In this embodiment, one or more functional layers can also be fabricated on the photosensitive layer, for example, at least one of a filter layer, an antireflection film, a packaging layer, etc. Further, it can also include Figure 6Perform corresponding optoelectronic performance tests on the circuit connection shown, and obtain the best signal-to-noise ratio by regulating the bottom gate operating voltage.

[0134] Figure 10 The flowchart of a specific preparation method M1000 is shown. Method M1000 can correspond to the global bottom gate structure of an embodiment such as Figure 4 The specific content of this method can be referred to the description of Figure 4 .

[0135] In step S1002, a photosensitive layer can be prepared on the wafer. The photosensitive layer can be prepared into a two-layer to three-layer structure, and the material of the photosensitive layer is determined according to the required detection wavelength range. And the photosensitive layer is prepared to promote the effective separation of photo-generated carriers. The photosensitive layer can be prepared into junction structures such as p-i-n heterojunction, p-n inverse heterojunction, n-n homojunction, p-p homojunction, n-p-n double heterojunction, p-n-p double heterojunction, Schottky junction, etc. In the present disclosure, the photosensitive layer is preferably a p-i-n heterojunction. For example, in the case of mid-wave infrared detection, the p-i-n junction of the photosensitive layer can be Ag2Te-HgTe-Bi2Se3. When the transistor-type photodetector is a short-wave infrared detector, the p-i-n junction of the photosensitive layer can be p-i-n GeSn, p-Si / i-Ge / n-Ge, p-PbS-EDT quantum dots / i-halogen framework PbS quantum dots / n-ZnO or n-TiO2. When the transistor-type photodetector is a near-infrared wave detector, the p-i-n junction of the photosensitive layer can be p-NiOx / i-halogen framework PbS quantum dots / n-ZnO. When the transistor-type photodetector is a visible light detector, the p-i-n junction of the photosensitive layer can be a p-i-n silicon heterojunction. When the transistor-type photodetector is an ultraviolet light detector, the p-i-n junction of the photosensitive layer can be a ZnO thin film, a p-i-n heterojunction of p-Si / i-ZnO / n-ZnO.

[0136] In step S1004, a dielectric layer can be prepared on the photosensitive layer, where the material of the dielectric layer can be as described above. For example, electron beam evaporation of yttrium metal can be used and then thermal oxidation is carried out to form yttrium oxide on the carbon nanotube film as a high dielectric constant dielectric layer. In addition, a multi-layer structure of oxides can also be formed to form a high dielectric constant dielectric layer.

[0137] In step S1006, a channel layer can be deposited on the dielectric layer. For example, a network-shaped or aligned high-purity carbon nanotube thin film can be deposited. As described above, other two-dimensional materials such as crystalline or amorphous silicon, semiconductor metal oxides, transition metal chalcogenides, graphene, semiconductor nanowires, and organic semiconductors can also be used for deposition to form the channel layer. In the present disclosure, the density of the deposited carbon nanotubes can be correspondingly controlled. In addition, after the carbon nanotube deposition is completed, high-temperature annealing can be performed, and an organic polymer on the surface of the carbon nanotubes can be removed by using, for example, a yttrium oxide cleaning technique.

[0138] In step S1008, a first electrode and a second electrode can be prepared. Specifically, microfabrication processes such as exposure and electron beam coating can be used to deposit a metal material to prepare the first electrode and the second electrode. The materials of the first electrode and the second electrode can be one or more of metal materials such as Ti, Pd, or Au.

[0139] In step S1010, processes such as exposure and dry etching can be used to pattern the carbon nanotube thin film, and the carbon nanotubes outside the channel region can be etched to avoid electrical crosstalk between devices.

[0140] In step S1012, a gate insulating layer can be deposited on the channel layer. The gate insulating layer can be any insulating medium.

[0141] In step S1014, a gate electrode can be prepared on the gate insulating layer, and microfabrication processes such as exposure and electron beam coating can be used to deposit a metal material to form the gate electrode.

[0142] It may also include performing circuit connections as shown in Figure 6 and conducting corresponding optoelectronic performance tests, obtaining the best signal-to-noise ratio by regulating the bottom gate operating voltage, etc. In addition, as described above, it may also include steps of preparing a first functional layer and / or a second functional layer. The first functional layer can be at least one of a light filtering layer, an antireflection film, a passivation layer, etc., and can be disposed between the photosensitive layer and the transparent substrate. The second functional layer can be disposed between the photosensitive layer and the dielectric layer, and this second functional layer can be used to adjust the threshold voltage of the transistor. For example, this second functional layer can be a metal layer, and in addition, it can be an antireflection film, etc.

[0143] Figure 11A device schematic diagram of the global bottom gate structure described according to the present disclosure is shown. Among them, the dielectric layer 140 is a high-k dielectric layer. Through the design of this dielectric layer 140, it is possible to achieve that the change in the electric field signal of the built-in electric field of the photosensitive layer 150 acts on the channel layer 130 in a capacitive coupling manner. According to the unique device structure of the present disclosure, it is possible to effectively amplify the optical signal (optical voltage) in a capacitive coupling manner, so that a higher responsivity / external quantum efficiency can be obtained. Moreover, in this structure, photo-generated excitons do not need to be completely separated, and only an electric dipole potential needs to be generated, that is, a potential distribution needs to be generated. Therefore, the photodetector of the present disclosure can have an extremely fast response speed. Therefore, according to the device structure of the present disclosure, it is possible to solve the drawback that it is difficult to achieve both high responsivity and speed in traditional Photogating-type photodetectors, and it can also well solve the problems that the photosensitive layer material contacts the channel layer material, making the transport characteristics of the channel layer material and the sensing mechanism complicated due to the influence of the photosensitive layer material.

[0144] In the present disclosure, the photosensitive layer 150 is designed to form a photo-voltage signal by separating photo-generated carriers through the built-in electric field, and the dielectric layer 10 is designed to amplify the photo-voltage signal by capacitive coupling and act on the channel layer 130.

[0145] In the structure of the present disclosure, the action range of the built-in electric field 154 (shown by the dotted line in the figure) can be formed in the entire junction region. Therefore, the problem of the limited action range of the built-in electric field of the BFBD device can be well solved, because in the BFBD device, the action range of the built-in electric field is only in the region of about 50 nm near the source-drain contact. Therefore, it is difficult for the BFBD device to obtain a high signal-to-noise ratio.

[0146] Here, taking a short-wave infrared detector as an example for illustration, the photosensitive layer 150 can be a two-layer or three-layer junction structure composed of PbS quantum dots and ZnO. For example, preferably, it can be a p-n junction composed of a PbS quantum dot layer with EDT ligand and a ZnO layer. Among them, the ZnO layer is assembled on the dielectric layer 140, and then a PbS quantum dot thin film with EDT ligand is spin-coated on the ZnO layer. More preferably, the photosensitive layer 150 can be a p-i-n junction structure. The ZnO layer can be assembled on the dielectric layer 140, a PbS quantum dot thin film with a halogen skeleton is formed on the ZnO layer, and then a PbS quantum dot thin film with EDT ligand is formed to form the photosensitive layer.

[0147] Figures 12 to 16 A schematic diagram of the performance indicators of a short-wave infrared detection device made with a channel layer of network-shaped carbon nanotubes, a dielectric layer of yttrium oxide, and a photosensitive layer of a p-PbS-EDT quantum dot / i-halogen skeleton PbS quantum dot / n-ZnO p-i-n junction is shown.

[0148] Figure 12 shows the real-time optoelectronic response of the device under 1300 nm light illumination at different optical powers (where V GS = 0 V, V DS = -0.1 V). According to the test results, it can be clearly seen that the device fabricated according to the technical solution of the present disclosure can achieve the detection of extremely weak light with an optical power density lower than 130 nW / cm 2 .

[0149] Figure 13 shows the responsivity and photocurrent extracted from the device under 1300 nm light illumination. According to the test results, it can be clearly seen that the responsivity to 1300 nm weak light is as high as 10 4 A / W

[0150] Figure 14 shows the response speed (left) and recovery speed (right) of the device under 1300 nm light illumination (V GS = 0 V, V DS = -0.1 V). It can be clearly seen that the response speed and recovery speed can reach the sub-ms level.

[0151] Figure 15 shows the noise spectrum and specific detectivity of the device under 1300 nm light illumination. It can be clearly seen that the specific detectivity D* of the device to weak light can be as high as 6×10 13 at 1 Hz; it can be as high as 3×10 14 at 400 Hz; and it can be as high as 6×10 14 at 1000 Hz.

[0152] In Figure 16 shows a schematic diagram of the performance comparison between the device fabricated according to the technical solution of the present disclosure and the existing device. From the comparison results, it can be seen that the device according to the present disclosure is significantly superior to the existing device in terms of both response speed and specific detectivity.

[0153] In the description of this specification, the description with reference to terms such as "one embodiment / way", "some embodiments / ways", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment / way or example are included in at least one embodiment / way or example of this application. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment / way or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments / ways or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments / ways or examples described in this specification and the features of different embodiments / ways or examples.

[0154] In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, "a plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0155] Those skilled in the art should understand that the above embodiments are only for clearly explaining the present disclosure and are not intended to limit the scope of the present disclosure. For those skilled in the art, other changes or modifications can be made based on the above disclosure, and these changes or modifications are still within the scope of the present disclosure.

Claims

1. A transistor-type photodetector, characterized in that, Comprising: A first electrode; A second electrode, which is spaced apart from the first electrode; A channel layer, which is disposed at least between the first electrode and the second electrode; A photosensitive layer, which is designed as a p-i-n heterojunction structure, and the material of the photosensitive layer is determined by the wavelength band to be detected. In the p-i-n heterojunction structure, the set thickness of the i-region is greater than the set thicknesses of the p-region and the n-region; A dielectric layer, which is disposed between the channel layer and the photosensitive layer, and is used to apply the change of the electric field signal of the built-in electric field of the photosensitive layer to the channel layer in a capacitive coupling manner, and the action range of the built-in electric field is formed in the region of the entire p-i-n heterojunction structure; A second functional layer, which is designed between the photosensitive layer and the dielectric layer and is used to adjust the threshold voltage of the transistor-type photodetector; Wherein, the gate voltage of the transistor-type photodetector can be regulated so that the channel layer is biased to the optimal operating point to achieve the optimal signal-to-noise ratio.

2. The transistor-type photodetector according to claim 1, characterized in that, The dielectric layer is a high-k dielectric layer.

3. The transistor-type photodetector according to claim 1, wherein Further comprising: A gate and a gate insulating layer, and the gate insulating layer is disposed between the channel layer and the gate.

4. The transistor-type photodetector according to claim 3, wherein The transistor-type photodetector is configured as a global bottom-gate structure, and the substrate in the global bottom-gate structure is a doped substrate and serves as the gate; or The transistor-type photodetector is configured as a local bottom-gate structure, wherein the local bottom-gate structure includes a substrate, and the gate is formed in the substrate.

5. The transistor-type photodetector according to claim 3, wherein The transistor-type photodetector is configured as a top-gate structure. In the top-gate structure, it includes a substrate, the substrate is a transparent substrate and is disposed under the photosensitive layer, and the gate insulating layer is disposed above the channel layer.

6. The transistor-type photodetector according to claim 5, wherein A first functional layer is designed between the substrate and the photosensitive layer, and the first functional layer is at least one of a filter layer, an antireflection film, and a passivation layer.

7. The transistor-type photodetector according to any one of claims 1 to 6, characterized in that, The dielectric layer is a single-layer dielectric layer made of a high-k material or a dielectric layer of two or more layers made of different high-k materials.

8. A transistor-type photodetector, characterized in that, Comprising: A first electrode; A second electrode, which is spaced apart from the first electrode; A carbon nanotube channel layer, which is disposed at least between the first electrode and the second electrode; A photosensitive layer, which is designed as a p-i-n heterojunction structure, and the material of the photosensitive layer is determined by the wavelength band to be detected. In the p-i-n heterojunction structure, the set thickness of the i-region is greater than the set thicknesses of the p-region and the n-region; A dielectric layer, which is disposed between the carbon nanotube channel layer and the photosensitive layer, and is used to apply the change of the electric field signal of the built-in electric field of the photosensitive layer to the channel layer in a capacitive coupling manner, and the action range of the built-in electric field is formed in the region of the entire p-i-n heterojunction structure; A second functional layer, which is designed between the photosensitive layer and the dielectric layer and is used to adjust the threshold voltage of the transistor-type photodetector; Among them, the gate voltage of the transistor-type photodetector can be regulated so that the channel layer is biased to the optimal operating point to achieve the optimal signal-to-noise ratio.

9. The transistor-type photodetector according to claim 8, characterized in that, The dielectric layer is a high-k dielectric layer.

10. The transistor-type photodetector according to claim 8, characterized in that, It further includes: A gate and a gate insulating layer, and the gate insulating layer is disposed between the carbon nanotube channel layer and the gate.

11. The transistor-type photodetector according to claim 10, wherein The transistor-type photodetector is configured as a global bottom-gate structure, and the substrate in the global bottom-gate structure is a doped substrate and serves as the gate; or The transistor-type photodetector is configured as a local bottom-gate structure, wherein the local bottom-gate structure includes a substrate, and the gate is formed in the substrate.

12. The transistor-type photodetector according to claim 10, wherein The transistor-type photodetector is configured as a top-gate structure. In the top-gate structure, there is a substrate, the substrate is a transparent substrate and is disposed under the photosensitive layer, and the gate insulating layer is disposed on the carbon nanotube channel layer.

13. The transistor-type photodetector according to claim 12, wherein A first functional layer is designed between the substrate and the photosensitive layer, and the first functional layer is at least one of a filter layer, an antireflection film, and a passivation layer.

14. The transistor-type photodetector according to any one of claims 8 to 13, characterized in that, The dielectric layer is a single-layer dielectric layer made of a high-k material or a dielectric layer of two or more layers made of different high-k materials.

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