CN114613873A - Transistor photodetector and preparation method thereof - Google Patents

Abstract

The present disclosure provides a transistor-type photodetector, comprising: a first electrode; a second electrode, the second electrode being spaced apart from the first electrode; a channel layer, the channel layer being disposed at least between the first electrode and the second electrode ; a photosensitive layer, the photosensitive layer 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; and a dielectric layer, the dielectric layer is arranged between the channel layer and the photosensitive layer. The present disclosure also provides a transistor-type photodetector and a preparation method thereof.

Description

Transistor photodetector and preparation method thereof

technical field

The present disclosure relates to a transistor-type photodetector and a preparation method thereof.

Background technique

A photodetector is a functional device that converts optical signals into electrical signals. 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 applications in military (remote sensing, aiming, night vision, stealth, guidance), aerospace, biodiagnosis, civil (autonomous driving, mobile phone infrared lenses, smart home, wireless sensing, gas monitoring) and many other fields. Value.

Commercial photodetectors are currently 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 1100nm) and can only be used for visible and near-infrared detection. The cut-off wavelength of germanium reaches 1.7um, but its performance is poor (indirect band gap, large dark current, low saturation current), and most of them have been replaced by indium gallium arsenide. However, indium gallium arsenide and mercury cadmium telluride need to be epitaxially grown on III-V, CdTe or ZnCdTe substrates, which are difficult to synthesize, complex in process and high in cost, and incompatible with silicon-based readout circuits, requiring copper pillars or indium pillars. Heterogeneous bonding is performed, and additional cooling devices are mostly required, which makes current high-performance infrared detectors and chips expensive.

In order to improve the external quantum efficiency, a Photogating (light-gating) type photodetector is currently designed, that is, quantum dots such as PbS and perovskite with high absorption coefficient are used to form a type II heterojunction with carbon nanotubes. The interface of the two separates to form additional electric field modulation. Such devices tend to achieve higher gain, but slower response and recovery. In 2017, Frank ^Koppens et al. reported a photogating short-wave infrared detector based on graphene/PbS quantum dots and a focal plane image sensor with a scale of 288 × 388 pixels. The highest is 7×10 ¹³ Jones, but there are problems such as slow speed (response time 10ms, forced recovery of gate voltage pulse), small dynamic range, and low switching ratio. In 2021, Sun Dongming and others from the Institute of Metal Research, Chinese Academy of Sciences used CsPbBr ₃ and carbon nanotubes to build a Photogating photodetector, with a responsivity of 10 ⁷ A/W for visible light at 405 and 516 nm, and a D* of 10 ¹⁶ Jones, but the response The time is tens of ms-s, and additional grid voltage pulses are required to force the detector to return to the baseline.

In addition, with the development of carbon nanotube technology, carbon nanotubes are gradually used in devices. However, carbon nanotubes have not yet developed practical photodetectors in the field of photodetection such as infrared. The main reasons are as follows: 1. The light absorption of single or thin-film carbon nanotubes is limited and the external quantum efficiency is low; 2. BFBD It is an ideal carbon nanotube diode structure, but the built-in electric field is only in the area of about 50nm near the source-drain contact, limited by the diffraction limit, the pixel size of infrared detectors is mostly larger than 1um, so it is difficult for BFBD devices to obtain higher. Signal-to-noise ratio; 3. Photogating structure is an important way to overcome low quantum efficiency and small built-in electric field range, but under the current photogating device architecture, the performance of photodetectors is not good, and there is a responsivity/external quantum efficiency conflict with speed.

Therefore, how to design a new photodetector structure to break through the current predicament is a problem that needs to be solved.

SUMMARY OF THE INVENTION

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 corresponding speed, a higher responsivity/external quantum efficiency and a larger signal-to-noise ratio can be obtained.

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

the first electrode;

a second electrode spaced apart from the first electrode;

a channel layer, the channel layer is at least disposed between the first electrode and the second electrode;

A photosensitive layer, the photosensitive layer 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; and

A dielectric layer is provided between the channel layer and the photosensitive layer.

According to the transistor-type photodetector of at least one embodiment of the present disclosure, the dielectric layer is used for applying the electric field signal change of the built-in electric field of the photosensitive layer to the channel layer in a capacitive coupling manner.

According to the transistor-type photodetector of at least one embodiment of the present disclosure, the dielectric layer is a high dielectric constant dielectric layer.

The transistor-type photodetector according to at least one embodiment of the present disclosure further includes a gate electrode and a gate insulating layer, the gate insulating layer being disposed between the channel layer and the gate electrode.

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

The transistor-type photodetector is configured as a partial bottom gate structure, wherein the partial bottom gate structure includes a substrate in which the gate is formed.

A transistor-type photodetector according to at least one embodiment of the present disclosure, the transistor-type photodetector is configured as a top gate structure, the top gate structure includes a substrate, the substrate is a transparent substrate and is disposed on the photosensitive layer Below, the gate insulating layer is disposed on the channel layer.

According to the transistor-type photodetector of at least one embodiment of the present disclosure, a functional layer is designed on the outer side of the photosensitive layer, and the functional layer is at least one of a filter layer, an antireflection film, and an encapsulation layer.

According to the transistor-type photodetector of 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.

According to the transistor-type photodetector of 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 a filter layer, an antireflection film and a passivation layer at least one of; and/or

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.

According to the transistor-type photodetector of 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.

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

the first electrode;

a second electrode spaced apart from the first electrode;

a carbon nanotube channel layer, the carbon nanotube channel layer is at least disposed between the first electrode and the second electrode;

Photosensitive layer, the photosensitive layer is designed in p-i-n heterojunction, p-n inversion heterojunction, n-n homoheterojunction, p-p homoheterojunction, n-p-n double heterojunction, p-n-p double heterojunction and Schottky junction One, the material of the photosensitive layer is determined by the wavelength band to be detected; and

A dielectric layer is provided between the carbon nanotube channel layer and the photosensitive layer.

According to the transistor-type photodetector of at least one embodiment of the present disclosure, the dielectric layer is configured to act on the carbon nanotube channel layer by capacitively coupling the electric field signal change of the built-in electric field of the photosensitive layer.

According to the transistor-type photodetector of at least one embodiment of the present disclosure, the dielectric layer is a high dielectric constant dielectric layer.

The transistor-type photodetector according to at least one embodiment of the present disclosure further includes a gate electrode and a gate insulating layer, the gate insulating layer being disposed between the carbon nanotube channel layer and the gate electrode.

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

The transistor-type photodetector is configured as a partial bottom gate structure, wherein the partial bottom gate structure includes a substrate in which the gate is formed.

A transistor-type photodetector according to at least one embodiment of the present disclosure, the transistor-type photodetector is configured as a top gate structure, the top gate structure includes a substrate, the substrate is a transparent substrate and is disposed on the photosensitive layer Below, the gate insulating layer is disposed on the carbon nanotube channel layer.

According to the transistor-type photodetector of at least one embodiment of the present disclosure, a functional layer is designed on the outer side of the photosensitive layer, and the functional layer is at least one of a filter layer, an antireflection film, and an encapsulation layer.

According to the transistor-type photodetector of 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 energy band matching or improve mechanical and electrical stability.

According to the transistor-type photodetector of 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 a filter layer, an antireflection film and a passivation layer at least one of; and/or

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.

According to the transistor-type photodetector of 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.

According to yet another aspect of the present disclosure, a method for fabricating a transistor-type photodetector includes:

forming a gate insulating layer over the doped substrate, wherein the pedestal serves as a gate;

preparing a channel layer on the gate insulating layer;

preparing a first electrode and a second electrode;

preparing a high dielectric constant material over the channel layer to form a dielectric layer; and

A photosensitive layer is prepared on the dielectric layer.

According to yet another aspect of the present disclosure, a method for fabricating a transistor-type photodetector includes:

preparing the gate in the substrate;

preparing an upper gate insulating layer over the substrate and the gate;

preparing a channel layer on the gate insulating layer;

preparing a first electrode and a second electrode;

preparing a high dielectric constant material over the channel layer to form a dielectric layer; and

A photosensitive layer is prepared on the dielectric layer.

According to yet another aspect of the present disclosure, a method for fabricating a transistor-type photodetector includes:

Prepare a photosensitive layer on a transparent substrate;

preparing a high dielectric constant material on the photosensitive layer to form a dielectric layer;

preparing a channel layer on the dielectric layer;

preparing a first electrode and a second electrode;

Prepare at least a gate insulating layer on the channel layer; and

A gate is fabricated over the gate insulation.

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.

According to the preparation method of at least one embodiment of the present disclosure, the channel layer is a carbon nanotube channel layer.

Description of drawings

The accompanying drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure, are included to provide a further understanding of the disclosure, and are incorporated in and constitute the present specification part of the manual.

FIG. 1 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

FIG. 2 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

FIG. 3 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

FIG. 4 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

FIG. 5 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

FIG. 6 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

FIG. 7 is a flowchart of a preparation method according to an embodiment of the present disclosure.

FIG. 8 is a flowchart of a manufacturing method according to an embodiment of the present disclosure.

FIG. 9 is a flowchart of a preparation method according to an embodiment of the present disclosure.

FIG. 10 is a flowchart of a manufacturing method according to an embodiment of the present disclosure.

11 is a schematic structural diagram of a photodetector according to an embodiment of the present disclosure.

12 to 16 are schematic diagrams of performance indicators of photodetectors according to embodiments of the present disclosure.

Detailed ways

The present disclosure will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the related content, but not to limit the present disclosure. In addition, it should be noted that, for the convenience of description, only the parts related to the present disclosure are shown in the drawings.

It should be noted that the embodiments of the present disclosure and the features of the embodiments may be combined with each other unless there is conflict. The technical solutions of the present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

Unless otherwise stated, the illustrated exemplary embodiments/embodiments are to be understood as exemplary features providing various details of some ways in which the technical concept of the present disclosure may be implemented in practice. Therefore, unless otherwise stated, the features of various embodiments/embodiments may be additionally combined, separated, interchanged and/or rearranged without departing from the technical concept of the present disclosure.

The use of cross-hatching and/or hatching in the drawings is generally used to clarify boundaries between adjacent components. As such, unless stated, the presence or absence of cross-hatching or shading does not convey or represent any particular material, material properties, dimensions, proportions, commonalities between the illustrated components and/or any other characteristics of the components, any preferences or requirements for attributes, properties, etc. Furthermore, in the drawings, the size and relative sizes of components may be exaggerated for clarity and/or descriptive purposes. When example embodiments may be implemented differently, the specific process sequence may be performed in a different order than described. For example, two consecutively described processes may be performed substantially concurrently or in the reverse order of that described. In addition, the same reference numerals denote the same components.

When an element is referred to as being "on" or "over", "connected to" or "coupled to" another element, the element can be directly on, directly connected to, the other element Either directly coupled to the other component, or intermediate components may be present. However, when an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element, there are no intervening elements present. To this end, the term "connected" may refer to a physical connection, electrical connection, etc., with or without intervening components.

For convenience, in the following description, various device geometries according to embodiments of the present invention are described with respect to the devices in the orientations shown in the figures. Where terms such as "above," "over," "lateral," "vertical," etc. are used in the description, these should not be construed to imply that such embodiments are limited to the particular orientation shown in the figures. It should be readily understood that the devices described herein will function correctly regardless of the physical orientation of the device or the device in which it is incorporated, and the following description should be interpreted accordingly. Additionally, transistors according to embodiments of the present invention include semiconductor regions, which may include semiconductors, semi-metals, or degenerately doped semiconductors, or combinations thereof. Accordingly, references herein to "semiconductor regions" should be interpreted accordingly.

The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting. As used herein, the singular forms "a" and "the" are intended to include the plural forms as well, unless the context clearly dictates otherwise. Furthermore, when the terms "comprising" and/or "comprising" and their variants are used in this specification, it is indicated that the stated features, integers, steps, operations, parts, components and/or groups thereof are present, but not excluded One or more other features, integers, steps, operations, parts, components and/or groups thereof are present or additional. Note also that, as used herein, the terms "substantially," "approximately," and other similar terms are used as terms of approximation and not as terms of degree, as they are used to explain what one of ordinary skill in the art would recognize Inherent deviations from measured, calculated and/or provided values.

According to one embodiment of the present disclosure, a transistor-type photodetector is provided, wherein the transistor-type photodetector may be an infrared detector, a visible light detector, an ultraviolet detector, a terahertz detector, and the like.

FIG. 1 shows a schematic diagram of a transistor-type photodetector according to one embodiment of the present disclosure.

As shown in FIG. 1 , 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, wherein the first electrode 110 may be a source electrode or a drain electrode, and the second electrode 120 may be a drain electrode or a source electrode. A channel layer 130 may be disposed between the first electrode 110 and the second electrode 120 .

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 semiconducting metal oxides, conductive or semiconducting polymers, doped semiconductors, graphene, and two-dimensional (2D) semiconductors, among others . 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).

The photodetector 10 may include a channel layer 130 . The channel layer 130 is disposed at least in a 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, two-dimensional materials such as crystalline or amorphous silicon, semiconductor metal oxides, transition metal chalcogenides, graphene, carbon nanotubes, semiconductor nanowires, organic semiconductors, and the like.

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

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.

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 medium. Examples of materials that can be used for the dielectric layer 140 include, but are not limited to: SiO ₂ , HfO ₂ , ZrO ₂ , Ta ₂ O ₅ , Y ₂ O ₃ , Nb ₂ O ₅ , Al ₂ O ₃ , TiO ₂ , CeO ₂ , In ₂ O ₃ , RuO 2 , MgO, SrO, B ₂ O ₃ , SnO ₂ , PbO, PbO ₂ , Pb ₃ O ₄ , V ₂ O ₃ , La ₂ O ₃ , Pr ₂ O ₃ , Sb ₂ O ₃ , Sb ₂ Any of O ₅ , CaO, and the like. 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 can also be a structure with more than two layers, for example, a multi-layer structure formed by different materials listed above. The dielectric layer 140 may be prepared by a process such as exposure, thermal oxidation, or ALD.

In the present disclosure, the dielectric layer 140 is preferably a high dielectric constant dielectric layer. Through the design of the dielectric layer 140 , the electric field signal change of the built-in electric field of the photosensitive layer 150 can be amplified and acted on the channel layer 130 in a capacitive coupling manner. According to the unique device structure of the present disclosure, the effective amplification of the optical signal (photovoltage) can be realized in a capacitive coupling manner, so that higher responsivity/external quantum efficiency can be obtained. In the structure of the present disclosure, the photogenerated excitons do not need to be completely separated, but only need to generate electric dipole potential, that is, to generate potential distribution. 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 high responsivity and speed in the traditional photogating type photodetector can be solved, and the contact between the photosensitive layer material and the channel layer material can also be well solved. The layer material affects the transport properties of the channel layer material and the sensing mechanism becomes complicated.

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 heterojunction, p-n inversion heterojunction, n-n homoheterojunction, p-p homoheterojunction, n-p-n double heterojunction, p-n-p double heterojunction, and Schottky junction. In the present disclosure, preferably, the photosensitive layer 150 can be designed as a p-i-n heterojunction. In the junction structure of the p-i-n heterojunction, the p region and the n region can be set thinner, and the i region can be set thicker. That is to say, the setting thickness of the i region is larger than that of the p region and the n region. This setup can effectively suppress the tunneling effect of majority carriers, with high sensitivity, small junction capacitance and small circuit constant, wide depletion layer, short diffusion and transit time, and fast response.

In the present disclosure, the photosensitive layer 150 may be formed in the following manner. As an example, amorphous or polycrystalline thin films, such as thin films of ZnO, TiO ₂ , Si, PbS, PbSe, etc., can be prepared by thermal evaporation, magnetron sputtering, electron beam evaporation, atomic layer deposition, chemical vapor deposition, etc. to form the photosensitive layer 150 . As another example, the photosensitive layer 150 may be formed by a polycrystalline or single crystal colloidal quantum dot film, for example, including Pb-based, Hg-based, Cd-based, Si, oxide, perovskite and other quantum dot systems, such as PbS, Quantum dots of PbSe, HgTe, Si, CdTe, CdS, ZnO and their core-shell structures. As another example, the photosensitive layer 150 may be formed by a thin film composed of single crystal or polycrystalline nanowires, nanosheets, etc., such as GaAs, Te, etc. nanowires and ZnO, HgTe, etc. nanosheets.

As an example, when the transistor-type photodetector is a mid-wave infrared detector, the pin junction of the photosensitive layer 150 may be Ag ₂ Te-HgTe-Bi ₂ Se ₃ . When the transistor-type photodetector is a short-wave infrared detector, the pin junction of the photosensitive layer 150 may be a pi-nGeSn, p-Si/i-Ge/n-Ge, PbS-EDT quantum dot/i-halogen skeleton PbS quantum dots/n-ZnO or n- _TiO2 . When the transistor-type photodetector is a near-infrared wave detector, the pin junction of the photosensitive layer 150 can be a PbS quantum dot/n-ZnO of p-NiOx/i-halogen skeleton, and when the transistor-type photodetector is a visible light detection In the case of a device, the pin junction of the photosensitive layer 150 may be a pin silicon heterojunction. When the transistor-type photodetector is an ultraviolet photodetector, the pin junction of the photosensitive layer 150 may be a ZnO thin film or a pin heterojunction of p-Si/i-ZnO/n-ZnO.

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

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, so the problem of the limited action range of the built-in electric field in the BFBD device can be well solved. In the BFBD device, the action of the built-in electric field The range is only about 50 nm near the source-drain contact, so it is difficult to obtain a high signal-to-noise ratio for BFBD devices.

The photodetector 10 may include a gate insulating layer 160 . The gate insulating layer 160 may be any insulating medium, for example, may be SiO ₂ . A global bottom gate structure is shown in FIG. 1 . In the global bottom gate structure, the doped substrate 170 may serve as a gate, and the gate insulating layer 160 may be disposed between the substrate 170 and the channel layer 130 .

FIG. 2 shows another embodiment according to the present disclosure. The difference between this embodiment and the content described with reference to FIG. 1 is that a functional layer 180 may be provided on the outer side of the photosensitive layer 150, wherein the functional layer 180 may be one layer The structure can also be a multi-layer structure, for example, it can be at least one of a filter layer, an anti-reflection film, an encapsulation layer, and the like. The same content as the related description in FIG. 1 will not be repeated here.

FIG. 3 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 electrode 280 .

The specific description 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 first electrode 110 , the second electrode 120 , the channel layer 130 , the dielectric layer 260 Detailed description of layer 140 , photosensitive layer 150 and gate insulating layer 160 . For the sake of brevity, details are not repeated here.

The main difference between the embodiment of FIG. 3 and the embodiment of FIG. 1 is that a local bottom gate structure is used in FIG. 3 , while a global bottom gate structure is used in FIG. 1 .

In the embodiment of FIG. 3 , the gate electrode 280 may be made of metal materials such as Ti, Al, Sc, Ni, Pd, Au, and Pt, or may be a stacked structure of metal materials. In the present disclosure, the gate metal may be selected in order to achieve the threshold value of the control 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.

In the present disclosure, the substrate material may be silicon, glass, quartz, ITO, etc.; or flexible substrates such as flexible PI, PET, and the like.

In the embodiment of FIG. 3, a functional layer (as described in FIG. 2) can also be provided on the photosensitive layer 250, wherein the functional layer can be a one-layer structure or a multi-layer structure, such as a filter layer, a At least one of a reflective film, an encapsulation layer, and the like.

FIG. 4 shows a schematic diagram of a transistor-type photodetector 30 according to yet another embodiment of the present disclosure. The transistor-type photodetector 30 shown in FIG. 4 may be a back-incidence 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 electrode 380 may be included. The specific description of these parts can refer to the content described above, which is not repeated here.

In the present disclosure, the photosensitive layer 350 may be disposed on the substrate 370 . The substrate 370 may be provided in a transparent form (eg, made of glass, quartz, ITO, etc.), so that light can enter from the lower portion of the substrate 370 as shown in FIG. 4 and be irradiated to 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 between the gate insulating layer 360 and the channel layer 330 .

According to further embodiments of the present disclosure, as shown in FIG. 5 , the transistor-type photodetector 30 may further include a first functional layer 391 , wherein the first functional layer 391 may be a filter layer, an anti-reflection film, a passivation layer, etc. at least one of. 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 can be disposed between the photosensitive layer 350 and the dielectric layer 340, and the second functional layer 392 can be used to adjust the threshold voltage of the transistor-type photodetector, for example, the second functional layer 392 can be a metal layer, In addition, it may be a reflection enhancement film or the like.

According to the device structure of the present disclosure, the channel layer of the transistor photodetector can be biased to the optimum operating point by adjusting the gate voltage of the transistor photodetector to achieve the optimum signal-to-noise ratio. For example, after the circuit connection as shown in FIG. 6 can be used, the applied gate voltage V _GS can be regulated so that the channel layer is biased to the optimum operating point, thereby achieving the optimum signal-to-noise ratio.

According to the technical solution of the present disclosure, the problem that the action range of the built-in electric field of the BFBD device is limited and it is difficult to obtain a high signal-to-noise ratio can be effectively solved, and the responsivity/external quantum efficiency and The paradox of speed.

Especially in the case where the channel layer is made of carbon nanotube material, the technical solution of the present disclosure can simultaneously obtain faster response speed, higher responsivity/external quantum efficiency and larger signal-to-noise ratio. Specifically, network or array carbon nanotubes are deposited on wafers to achieve mass production of high-quality bottom-gate transistors. Due to the excellent charge transport properties of carbon nanotubes, rapid carrier transport can be achieved. ALD, thermal oxidation, etc. are used to deposit a high-k dielectric on the carbon nanotubes as a dielectric layer. The design of this dielectric layer can amplify the electric field signal change in a capacitive coupling way and act on the carbon nanotubes; Quantum thin films deposited by spin coating, sputtering, etc. are used as photosensitive layers, which have high external quantum efficiency and can achieve effective light absorption; p-p homo-heterojunction, n-p-n double heterojunction, p-n-p double heterojunction, Schottky junction, to achieve effective and rapid separation of photogenerated carriers to form photovoltage; by regulating the gate applied on the carbon nanotube bottom gate transistor pressure to bias the carbon nanotubes at the optimal working point to achieve the best signal-to-noise ratio.

According to yet another embodiment of the present disclosure, a method for fabricating a transistor-type photodetector is provided. FIG. 7 shows a flowchart of a preparation method M700 according to an embodiment of the present disclosure, and may include the following contents.

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 is 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.

According to specific embodiments of the present disclosure, the following method for fabricating a transistor-type photodetector is provided, wherein in the following description, carbon nanotubes are used as the channel layer for description.

FIG. 8 shows a flow chart of a specific preparation method M800. The method M800 may correspond to the global bottom gate structure in the embodiment of FIG. 1 , and the specific content of the method may refer to the description related to FIG. 1 .

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

In step S804, a channel layer may be deposited on the gate insulating layer, for example, a network-like or aligned high-purity carbon nanotube thin film may be deposited. As explained above, other two-dimensional materials such as crystalline or amorphous silicon, semiconductor metal oxides, transition metal chalcogenides, graphene, semiconductor nanowires, organic semiconductors, etc. can 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 nanotube deposition is completed, high temperature annealing may be performed, and a cleaning technique such as yttrium oxide may be used to remove organic polymers on the surface of the carbon nanotubes.

In step S806, the first electrode and the second electrode may be prepared. Specifically, the first electrode and the second electrode can be prepared by depositing a metal material by using a micro-machining process such as exposure and electron beam coating. The material of the first electrode and the second electrode may be one or more of metal materials such as Ti, Pd or Au.

In step S808, the carbon nanotube film may be patterned by processes such as exposure, dry etching, etc., and the carbon nanotubes outside the channel region are etched, so as to avoid electrical crosstalk between devices.

In step S810, a dielectric layer may be formed on the carbon nanotube thin film, wherein the material of the dielectric layer may be as described above. For example, metal yttrium can be deposited by electron beam evaporation and then thermally oxidized to form yttrium oxide on the carbon nanotube film as a high dielectric constant dielectric layer. In addition, an oxide of a multilayer structure can also be formed to form a high dielectric constant dielectric layer.

In step S812, a photosensitive layer may be prepared on the dielectric layer. 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 band. And the photoactive layer is prepared to promote the effective separation of photogenerated carriers. The photosensitive layer can be prepared into p-i-n heterojunction, p-n inverse heterojunction, n-n homoheterojunction, p-p homoheterojunction, n-p-n double heterojunction, p-n-p double heterojunction, Schottky junction and other junction structures.

In the present disclosure, the photoactive layer is preferably a pin heterojunction. For example, in the case of medium-wave infrared detection, the pin junction of the photosensitive layer can be Ag ₂ Te-HgTe-Bi ₂ Se ₃ . When the transistor-type photodetector is a short-wave infrared detector, the pin junction of the photosensitive layer can be pin GeSn, p-Si/i-Ge/n-Ge, p-PbS-EDT quantum dots/i-halogen skeleton PbS quantum dots/n-ZnO or n- _TiO2 . When the transistor-type photodetector is a near-infrared wave detector, the pin junction of the photosensitive layer can be p-NiOx/i-halogen skeleton PbS quantum dots/n-ZnO, and when the transistor-type photodetector is a visible light detector In the case of , the pin junction of the photosensitive layer may be a pin silicon heterojunction. When the transistor-type photodetector is an ultraviolet photodetector, the pin junction of the photosensitive layer can be a ZnO thin film or a pin heterojunction of p-Si/i-ZnO/n-ZnO.

In this embodiment, one or more functional layers may also be prepared on the photosensitive layer, such as at least one of a filter layer, an antireflection film, an encapsulation layer, and the like. Further, the circuit connection as shown in FIG. 6 may be performed, corresponding photoelectric performance tests are performed, and the optimal signal-to-noise ratio can be obtained by adjusting the operating voltage of the bottom gate.

FIG. 9 shows a flow chart of a specific preparation method M900. The method M900 may correspond to the local bottom gate structure of the embodiment of FIG. 3 , and the specific content of the method may refer to the description related to FIG. 3 .

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

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

In step S906, a channel layer may be deposited on the gate insulating layer, for example, a network-like or aligned high-purity carbon nanotube thin film may be deposited. As explained above, other two-dimensional materials such as crystalline or amorphous silicon, semiconductor metal oxides, transition metal chalcogenides, graphene, semiconductor nanowires, organic semiconductors, etc. can 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 nanotube deposition is completed, high temperature annealing may be performed, and a cleaning technique such as yttrium oxide may be used to remove organic polymers on the surface of the carbon nanotubes.

In step S908, a first electrode and a second electrode may be prepared. The first electrode and the second electrode can be prepared by depositing the metal material by using microfabrication processes such as exposure and electron beam coating. The material of the first electrode and the second electrode may be one or more of metal materials such as Ti, Pd or Au.

In step S910, the carbon nanotube thin film may be patterned by processes such as exposure, dry etching, etc., and the carbon nanotubes outside the channel region are etched, so as to avoid electrical crosstalk between devices.

In step S912, a dielectric layer may be formed on the carbon nanotube thin film, wherein the material of the dielectric layer may be as described above. For example, metal yttrium can be deposited by electron beam evaporation and then thermally oxidized to form yttrium oxide on the carbon nanotube film as a high dielectric constant dielectric layer. In addition, an oxide of a multilayer structure can also be formed to form a high dielectric constant dielectric layer.

In step S914, a photosensitive layer may be prepared on the dielectric layer. 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 desired detection band. And the photoactive layer is prepared to promote the effective separation of photogenerated carriers. The photosensitive layer can be prepared into p-i-n heterojunction, p-n inverse heterojunction, n-n homoheterojunction, p-p homoheterojunction, n-p-n double heterojunction, p-n-p double heterojunction, Schottky junction and other junction structures.

In the present disclosure, the photoactive layer is preferably a pin heterojunction. For example, in the case of medium-wave infrared detection, the pin junction of the photosensitive layer can be Ag ₂ Te-HgTe-Bi ₂ Se ₃ . When the transistor-type photodetector is a short-wave infrared detector, the pin junction of the photosensitive layer can be pin GeSn, p-Si/i-Ge/n-Ge, p-PbS-EDT quantum dots/i-halogen skeleton PbS quantum dots/n-ZnO or n- _TiO2 . When the transistor-type photodetector is a near-infrared wave detector, the pin junction of the photosensitive layer can be p-NiOx/i-halogen skeleton PbS quantum dots/n-ZnO, and when the transistor-type photodetector is a visible light detector In the case of , the pin junction of the photosensitive layer may be a pin silicon heterojunction. When the transistor-type photodetector is an ultraviolet photodetector, the pin junction of the photosensitive layer can be a ZnO thin film or a pin heterojunction of p-Si/i-ZnO/n-ZnO.

In this embodiment, one or more functional layers may also be prepared on the photosensitive layer, such as at least one of a filter layer, an antireflection film, an encapsulation layer, and the like. Further, the circuit connection as shown in FIG. 6 may be performed, corresponding photoelectric performance tests are performed, and the optimal signal-to-noise ratio can be obtained by adjusting the operating voltage of the bottom gate.

FIG. 10 shows a flow chart of a specific preparation method M1000. The method M1000 may correspond to the global bottom gate structure in the embodiment of FIG. 4 , and the specific content of the method may refer to the description about FIG. 4 .

In step S1002, a photosensitive layer may 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 band. And the photoactive layer is prepared to promote the effective separation of photogenerated carriers. The photosensitive layer can be prepared into pin heterojunction, pn inversion heterojunction, nn homoheterojunction, pp homoheterojunction, npn double heterojunction, pnp double heterojunction, Schottky junction and other junction structures. In the present disclosure, the photoactive layer is preferably a pin heterojunction. For example, in the case of medium-wave infrared detection, the pin junction of the photosensitive layer can be Ag ₂ Te-HgTe-Bi ₂ Se ₃ . When the transistor-type photodetector is a short-wave infrared detector, the pin junction of the photosensitive layer can be pin GeSn, p-Si/i-Ge/n-Ge, p-PbS-EDT quantum dots/i-halogen skeleton PbS quantum dots/n-ZnO or n- _TiO2 . When the transistor-type photodetector is a near-infrared wave detector, the pin junction of the photosensitive layer can be p-NiOx/i-halogen skeleton PbS quantum dots/n-ZnO, and when the transistor-type photodetector is a visible light detector In the case of , the pin junction of the photosensitive layer may be a pin silicon heterojunction. When the transistor-type photodetector is an ultraviolet photodetector, the pin junction of the photosensitive layer can be a ZnO thin film or a pin heterojunction of p-Si/i-ZnO/n-ZnO.

In step S1004, a dielectric layer may be prepared on the photosensitive layer, wherein the material of the dielectric layer may be as described above. For example, metal yttrium can be deposited by electron beam evaporation and then thermally oxidized to form yttrium oxide on the carbon nanotube film as a high dielectric constant dielectric layer. In addition, an oxide of a multilayer structure can also be formed to form a high dielectric constant dielectric layer.

In step S1006, a channel layer may be deposited on the dielectric layer, for example, a network-like or aligned high-purity carbon nanotube thin film may be deposited. As explained above, other two-dimensional materials such as crystalline or amorphous silicon, semiconductor metal oxides, transition metal chalcogenides, graphene, semiconductor nanowires, organic semiconductors, etc. can 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 nanotube deposition is completed, high temperature annealing may be performed, and a cleaning technique such as yttrium oxide may be used to remove organic polymers on the surface of the carbon nanotubes.

In step S1008, a first electrode and a second electrode may be prepared. Specifically, the first electrode and the second electrode can be prepared by depositing a metal material by using a micro-machining process such as exposure and electron beam coating. The material of the first electrode and the second electrode may be one or more of metal materials such as Ti, Pd or Au.

In step S1010, the carbon nanotube thin film may be patterned by a process such as exposure, dry etching, etc., and the carbon nanotubes outside the channel region are etched, so as to avoid electrical crosstalk between devices.

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

In step S1014, a gate electrode may be prepared on the gate insulating layer, and a metal material is deposited by micro-processing techniques such as exposure and electron beam coating to form the gate electrode.

It may also include making circuit connections as shown in FIG. 6 , conducting corresponding optoelectronic performance tests, and obtaining the best signal-to-noise ratio by adjusting the operating voltage of the bottom gate. Furthermore, as described above, a step of preparing the first functional layer and/or the second functional layer may also be included. The first functional layer may be at least one of a filter layer, an antireflection film, a passivation layer, etc., and may 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 the second functional layer can be used to adjust the threshold voltage of the transistor. For example, the second functional layer can be a metal layer, and can also be a reflection enhancement film.

FIG. 11 shows a device schematic diagram of the global bottom gate structure described in accordance with the present disclosure. The dielectric layer 140 is a high dielectric constant dielectric layer. Through the design of the dielectric layer 140 , the electric field signal change of the built-in electric field of the photosensitive layer 150 can be applied to the channel layer 130 in a capacitive coupling manner. According to the unique device structure of the present disclosure, the effective amplification of the optical signal (photovoltage) can be realized in a capacitive coupling manner, so that higher responsivity/external quantum efficiency can be obtained. Moreover, in this structure, the photogenerated excitons do not need to be completely separated, but only need to generate electric dipole potential, that is, to generate potential distribution, so 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 high responsivity and speed in the traditional photogating type photodetector can be solved, and the contact between the photosensitive layer material and the channel layer material can be well solved, so that the The photosensitive layer material affects the transport properties of the channel layer material and the sensing mechanism becomes complex.

In the present disclosure, the photosensitive layer 150 is designed to realize the separation of photogenerated carriers through a built-in electric field to form a photovoltage signal, and the dielectric layer 10 is designed to amplify the photovoltage signal through capacitive coupling and act on the channel layer 130 .

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 area, so 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 The range of the built-in electric field in the device is only about 50 nm near the source-drain contact, so it is difficult to obtain a high signal-to-noise ratio for BFBD devices.

Herein, a short-wave infrared detector is used as an example for description. The photosensitive layer 150 may be a two-layer or three-layer junction structure composed of PbS quantum dots and ZnO. For example, it is preferably a p-n junction composed of a PbS quantum dot layer of EDT ligand and a ZnO layer, wherein a ZnO layer is assembled on the dielectric layer 140, and then a PbS quantum dot film of EDT ligand is spin-coated on the ZnO layer. More preferably, the photosensitive layer 150 may be a p-i-n junction structure. A ZnO layer can be assembled on the dielectric layer 140, a PbS quantum dot film with halogen skeletons is formed on the ZnO layer, and a PbS quantum dot film with EDT ligands is formed on the ZnO layer to form a photosensitive layer.

Figures 12 to 16 show the p-i-n junction where the channel layer adopts network carbon nanotubes, the dielectric layer adopts yttrium oxide, and the photosensitive layer adopts p-PbS-EDT quantum dots/i-halogen skeleton PbS quantum dots/n-ZnO p-i-n junction Schematic diagram of the performance indicators of the fabricated SWIR detection device.

Figure 12 shows the real-time photoelectric response of the device under 1300nm illumination conditions and different optical powers (wherein V _GS =0V, V _DS =-0.1V), according to the test results, it can be clearly seen that according to the technical solution of the present disclosure The fabricated device can realize the detection of very weak light with an optical power density below 130 nW/cm ² .

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

Figure 14 shows the response speed (left) and recovery speed (right) of the device under 1300nm illumination (V _GS =0V, V _DS =-0.1V), it can be clearly seen that the response speed and recovery speed can reach sub-ms level.

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

FIG. 16 shows a schematic diagram of the performance comparison between the device prepared 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 better than the existing device in terms of response speed and specific detection rate.

In the description of this specification, references to the terms "one embodiment/mode", "some embodiments/modes", "example", "specific example", or "some examples", etc. are intended to be combined with the description of the embodiment/mode A particular feature, structure, material, or characteristic described by way of example or example is included in at least one embodiment/mode or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment/mode or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments/means or examples. Furthermore, those skilled in the art may combine and combine the different embodiments/modes or examples described in this specification and the features of the different embodiments/modes or examples without conflicting each other.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present application, "plurality" means at least two, such as two, three, etc., unless expressly and specifically defined otherwise.

Those skilled in the art should understand that the above-mentioned embodiments are only for clearly illustrating the present disclosure, rather than limiting the scope of the present disclosure. For those skilled in the art, other changes or modifications may also be made on the basis of the above disclosure, and these changes or modifications are still within the scope of the present disclosure.

Claims (10)

1. 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;

the photosensitive layer is designed into a p-i-n heterojunction structure, and the material of the photosensitive layer is determined by a waveband to be detected; and

a dielectric layer disposed between the channel layer and the photosensitive layer.

2. The transistor-type photodetector of claim 1,

optionally, the dielectric layer is configured to apply an electric field signal change of a built-in electric field of the photosensitive layer to the channel layer in a capacitive coupling manner; or

Optionally, the dielectric layer is a high dielectric constant dielectric layer.

3. The transistor-type photodetector of claim 1 or 2,

optionally, the method further comprises: a gate electrode and a gate insulating layer disposed between the channel layer and the gate electrode; or

Optionally, the transistor-type photodetector is configured as a global bottom gate structure, and a substrate in the global bottom gate structure is a doped substrate and serves as the gate; or

Optionally, the transistor-type photodetector is configured as a partial bottom gate structure, wherein the partial bottom gate structure includes a substrate in which the gate electrode is formed; or

Optionally, the transistor-type photodetector is configured as a top-gate structure, where the top-gate structure includes a substrate, the substrate is a transparent substrate and is disposed below the photosensitive layer, and the gate insulating layer is disposed above the channel layer; or

Optionally, a functional layer is designed on the outer side of the photosensitive layer, and the functional layer is at least one of a filter layer, an antireflection film and an encapsulation layer; or alternatively

Optionally, a functional layer is designed between a p-i junction and i-n in a p-i-n heterojunction structure of the photosensitive layer, and the functional layer is used for realizing energy band matching or improving mechanical and electrical stability; or

Optionally, 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 anti-reflection film and a passivation layer; and/or a second functional layer is designed between the photosensitive layer and the dielectric layer, and the second functional layer is used for adjusting the threshold voltage of the transistor type photoelectric detector; or

Optionally, the dielectric layer is a single-layer dielectric layer made of a high-dielectric-constant material or two or more layers made of different high-dielectric-constant materials.

4. A transistor-type photodetector, comprising:

a first electrode;

a second electrode spaced apart from the first electrode;

a carbon nanotube channel layer disposed at least between the first electrode and the second electrode;

the light-sensitive layer is designed to be one of a p-i-n heterojunction, a p-n inversion heterojunction, an n-n homotype heterojunction, a p-p homotype heterojunction, an n-p-n double heterojunction, a p-n-p double heterojunction and a Schottky junction, and the material of the light-sensitive layer is determined by a waveband to be detected; and

and the dielectric layer is arranged between the carbon nano tube channel layer and the photosensitive layer.

5. The transistor-type photodetector of claim 4,

optionally, the dielectric layer is configured to apply an electric field signal change of a built-in electric field of the photosensitive layer to the carbon nanotube channel layer in a capacitive coupling manner; or alternatively

Optionally, the dielectric layer is a high dielectric constant dielectric layer.

6. The transistor-type photodetector of claim 4 or 5,

optionally, the method further comprises: the gate insulating layer is arranged between the carbon nano tube channel layer and the gate; or

Optionally, the transistor-type photodetector is configured as a global bottom gate structure, and a substrate in the global bottom gate structure is a doped substrate and serves as the gate; or alternatively

Optionally, the transistor-type photodetector is configured as a partial bottom gate structure, wherein the partial bottom gate structure includes a substrate in which the gate electrode is formed; or

Optionally, the transistor-type photodetector is configured as a top-gate structure, where the top-gate structure includes a substrate, the substrate is a transparent substrate and is disposed below the photosensitive layer, and the gate insulating layer is disposed above the carbon nanotube channel layer; or alternatively

Optionally, a functional layer is designed on the outer side of the photosensitive layer, and the functional layer is at least one of a filter layer, an antireflection film and an encapsulation layer; or

Optionally, a functional layer is designed between the junction structures of the photosensitive layer, and the functional layer is used for realizing energy band matching or improving mechanical and electrical stability; or

Optionally, 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 anti-reflection film and a passivation layer; and/or a second functional layer is designed between the photosensitive layer and the dielectric layer, and the second functional layer is used for adjusting the threshold voltage of the transistor type photoelectric detector; or

Optionally, the dielectric layer is a single-layer dielectric layer made of a high-dielectric-constant material or two or more layers made of different high-dielectric-constant materials.

7. A method for manufacturing a transistor type photodetector is characterized by comprising the following steps:

preparing a gate insulating layer over the doped substrate, wherein the base serves as a gate;

preparing a channel layer on the gate insulating layer;

preparing a first electrode and a second electrode;

preparing a high dielectric constant material on the channel layer to form a dielectric layer; and

and preparing a photosensitive layer on the dielectric layer.

8. A method for manufacturing a transistor photodetector includes:

preparing a grid electrode in a substrate;

preparing an upper gate insulating layer on the substrate and the gate;

preparing a channel layer on the gate insulating layer;

preparing a first electrode and a second electrode;

preparing a high-dielectric-constant material on the channel layer to form a dielectric layer; and

and preparing a photosensitive layer on the dielectric layer.

9. A method for manufacturing a transistor photodetector includes:

preparing a photosensitive layer on a transparent substrate;

preparing a high dielectric constant material on the photosensitive layer to form a dielectric layer;

preparing a channel layer on the dielectric layer;

preparing a first electrode and a second electrode;

preparing at least a gate insulating layer on the channel layer; and

and preparing a grid electrode on the grid insulation.

10. The production method according to any one of claims 7 to 9,

optionally, 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; or

Optionally, the channel layer is a carbon nanotube channel layer.

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