N and nanoparticle doped amorphous oxide thin film transistor-based detector

Abstract

The invention discloses a detector based on an amorphous oxide thin film transistor doped with N and nano-particles. The detector comprises a doped polycrystalline silicon substrate, an active layer and a metal electrode layer which are sequentially stacked, the doped polycrystalline silicon substrate comprises a silicon dioxide layer and heavily doped n-type polycrystalline silicon which are stacked; the silicon dioxide layer clings to the active layer; the active layer comprises at least two layers of N-doped amorphous indium gallium zinc oxide thin films; a metal nano-film is arranged on the side surface, facing the silicon dioxide layer, of the amorphous indium gallium zinc oxide film; the metal nano-film is formed by paving metal nano-particles; the metal electrode layer comprises a first metal electrode and a second metal electrode which are patterned and provided with a gap. According to the photoelectric detector, the double-layer metal nano thin film is constructed on the interface of the insulating layer and in the active layer body, and the two layers of amorphous indium gallium zinc oxide thin films are arranged and N doping is introduced, so that the detection rate is improved, the detection range is expanded, and meanwhile, the working stability of the device is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, and in particular to a detector based on an amorphous oxide thin-film transistor doped with N and nanoparticles. Background Technology

[0002] Amorphous oxide semiconductors (AOS) possess advantages such as high field-effect mobility, good uniformity, and low-temperature process compatibility, making them a key candidate material for transparent and flexible electronic devices. Indium gallium zinc oxide (IGZO), a typical AOS material, has been widely used in the fabrication of thin-film transistors (TFTs) and has demonstrated significant value in flat panel displays, neuromorphic computing, and optoelectronic devices. Particularly in photodetection, IGZO TFTs have attracted considerable attention in high-performance ultraviolet (UV) detection due to their wide bandgap. However, the wide bandgap of IGZO limits its photoresponse range primarily to the ultraviolet region, making it difficult to effectively absorb and respond to lower-energy visible light photons, thus restricting its detectivity and detection range.

[0003] In recent years, based on specific-sized metal nanostructures, the spectral response range of semiconductors can be effectively extended without altering their intrinsic band structure. The mechanism lies in the fact that when the incident light frequency matches the local surface plasmon resonance frequency of the metal nanostructure, surface free electrons undergo collective oscillation, generating high-energy "hot electrons" after resonant decay. If these hot electrons encounter a low Schottky barrier at the metal-semiconductor interface, they can be injected into the semiconductor conduction band and ultimately collected to form a photocurrent. This hot electron injection mechanism provides a new approach for the design of novel optoelectronic devices. While the introduction of nanoparticles can bring hot carriers and improve photoresponsivity, it also increases defects in the thin film, leading to increased hysteresis in the photodetector and thus reducing the device's operational stability. Summary of the Invention

[0004] This invention provides a detector based on N-doped and nanoparticle-doped amorphous oxide thin-film transistors, aiming to solve the problems of low detectivity, narrow detection range and poor operational stability of photodetectors based on indium gallium zinc oxide thin-film transistors in existing technologies.

[0005] In a first aspect, embodiments of this application provide a detector based on an amorphous oxide thin-film transistor doped with N and nanoparticles, wherein the photodetector comprises a doped polycrystalline silicon substrate, an active layer, and a metal electrode layer stacked sequentially. The doped polycrystalline silicon substrate includes a stacked silicon dioxide layer and heavily doped n-type polycrystalline silicon; the silicon dioxide layer is disposed in close contact with the active layer; The active layer comprises at least two N-doped amorphous indium gallium zinc oxide thin films; a metal nanofilm is disposed on the side of the amorphous indium gallium zinc oxide thin film facing the silicon dioxide layer; the metal nanofilm is formed by laying metal nanoparticles flat. The metal electrode layer includes a patterned first metal electrode and a second metal electrode, with a gap between the first metal electrode and the second metal electrode.

[0006] Secondly, embodiments of this application also provide a fabrication method, wherein the fabrication method is used to fabricate a detector based on N and nanoparticle doped amorphous oxide thin-film transistors as described in the first aspect above, the fabrication method comprising: A silicon dioxide wafer with heavily doped n-type polycrystalline silicon is used as the doped polycrystalline silicon substrate and cleaned. A silicon dioxide layer is attached to the upper surface of the heavily doped n-type polycrystalline silicon. A metal thin film is thermally evaporated on the silicon dioxide layer of the doped polycrystalline silicon substrate, and then annealed at 320~460 °C for 1.5~3 minutes to form metal nanoparticles; Amorphous indium gallium zinc oxide thin films are deposited on the silicon dioxide layer by magnetron sputtering using a mask, with an argon / nitrogen mixed gas introduced during the sputtering process. Repeat the above steps of thermal evaporation and magnetron sputtering to obtain two stacked N-doped amorphous indium gallium zinc oxide films as active layers; The device with the active layer is placed in a mixed atmosphere and annealed at a first annealing temperature for 20-45 minutes; the mixed atmosphere is composed of a mixture of nitrogen and oxygen. A patterned first metal electrode and a second metal electrode are obtained by thermal evaporation and metal thin film deposition using a mask. The device containing the metal electrodes is placed again in the mixed atmosphere and annealed at a second annealing temperature for 3 to 8 minutes to obtain the photodetector; the second annealing temperature is lower than the first annealing temperature.

[0007] This invention provides a detector based on an amorphous oxide thin-film transistor (SMT) doped with N and nanoparticles. The photodetector includes a doped polycrystalline silicon substrate, an active layer, and a metal electrode layer stacked sequentially. The doped polycrystalline silicon substrate includes a stacked silicon dioxide layer and heavily doped n-type polycrystalline silicon. The silicon dioxide layer is disposed in close proximity to the active layer. The active layer includes at least two N-doped amorphous indium gallium zinc oxide (IGaZO) thin films. A metal nanofilm is disposed on the side of the IGaZO thin film facing the silicon dioxide layer. The metal nanofilm is formed by the planar deposition of metal nanoparticles. The metal electrode layer includes a patterned first metal electrode and a second metal electrode, with a gap between the first and second metal electrodes. This photodetector constructs a double-layer metal nanofilm at the interface of the insulating layer and within the active layer. By setting two layers of amorphous IGaZO thin films and introducing N doping, the oxygen vacancy concentration in the active layer is effectively increased. This not only expands the photoresponse range but also further excites carriers in the channel, thereby enhancing the visible light response characteristics of the device. It improves the detectivity, expands the detection range, and enhances the device's operational stability. Attached Figure Description

[0008] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 A cross-sectional view of a detector based on N-doped and nanoparticle-doped amorphous oxide thin-film transistors provided in an embodiment of the present invention; Figure 2 A partial structural diagram of a detector based on N-doped and nanoparticle-doped amorphous oxide thin-film transistors provided in an embodiment of the present invention; Figure 3 A cross-sectional view of the comparative testing device provided in an embodiment of the present invention; Figure 4 Hysteresis comparison test diagram of the comparative test device provided in the embodiments of the present invention; Figure 5 The comparison test diagram shows the transfer characteristics of the comparative test device provided in the embodiments of the present invention; Figure 6 A comparative test chart of the detectivity of the comparative test device provided in the embodiments of the present invention; Figure 7 This is a schematic flowchart of the preparation method provided in an embodiment of the present invention.

[0010] Figure reference numerals: 1. Doped polycrystalline silicon substrate; 2. Active layer; 3. Metal electrode layer; 11. Silicon dioxide layer; 12. Heavily doped n-type polycrystalline silicon; 21. Metal nanofilm; 31. First metal electrode; 32. Second metal electrode; 33. Electrode channel. Detailed Implementation

[0011] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0012] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0013] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used in this specification and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes such combinations.

[0014] This invention provides a photodetector based on an amorphous oxide semiconductor thin-film transistor doped with N and nanoparticles, such as... Figure 1 and Figure 2 As shown, the photodetector includes a doped polycrystalline silicon substrate 1, an active layer 2, and a metal electrode layer 3 stacked sequentially. The doped polycrystalline silicon substrate 1 includes a silicon dioxide layer 11 and a heavily doped n-type polycrystalline silicon layer 12 stacked together. The silicon dioxide layer 11 is disposed in close contact with the active layer 2. The active layer 2 includes at least two N-doped amorphous indium gallium zinc oxide thin films. A metal nanofilm 21 is disposed on the side of the amorphous indium gallium zinc oxide thin film facing the silicon dioxide layer 11. The metal nanofilm 21 is formed by laying down metal nanoparticles. The metal electrode layer 3 includes a patterned first metal electrode 31 and a second metal electrode 32, with a gap between the first metal electrode 31 and the second metal electrode 32.

[0015] In the doped polycrystalline silicon substrate 1, the silicon dioxide layer 11 serves as the insulating layer interface. This application technique constructs a double-layer N-doped amorphous indium gallium zinc oxide film as the active layer 2. Furthermore, a double-layer metal nanofilm 21 is constructed between the insulating layer interface and the active layer 2. Each metal nanofilm 21 is formed by the planarization of metal nanoparticles (NPs), as shown in the specific structure below. Figure 1 As shown, the photodetector's optical response band is extended to 360–700 nm by utilizing the localized surface plasmon resonance (LSPR) effect of the metal nanofilm 21. Furthermore, N doping is introduced into the amorphous indium gallium zinc oxide film, effectively increasing the oxygen vacancy concentration in the active layer 2; the sub-bandgap states formed by these oxygen vacancies can absorb visible light and excite carriers in the channel, improving the detectivity and extending the detection range. The first metal electrode 31 and the second metal electrode 32 serve as the source (S) and drain (D) of the detector, respectively.

[0016] In a more specific embodiment, the metal nanofilm 21 is formed by spreading silver nanoparticles, and the thickness of the metal nanofilm 21 is 5-15 nm. Specifically, the thickness of the monolayer amorphous indium gallium zinc oxide film is 15-40 nm. The thickness of the silicon dioxide layer 11 in the doped polycrystalline silicon substrate 1 is 60-200 nm.

[0017] More specifically, the metal nanofilm 21 can be formed by spreading silver nanoparticles, wherein the thickness of the metal nanofilm 21 can be set to 5-15 nm, with a preferred embodiment having a thickness of 8-11 nm and an optimal embodiment having a thickness of 10 nm. The thickness of the monolayer amorphous indium gallium zinc oxide film can be set to 15-40 nm, with a preferred embodiment having a thickness of 18-25 nm and an optimal embodiment having a thickness of 20 nm.

[0018] The thickness of the silicon dioxide layer 11 can be set to 60-200nm, in a preferred embodiment it is set to 75-120nm, and in the optimal embodiment it can be set to 100nm.

[0019] In a more specific embodiment, such as Figure 2 As shown, the first metal electrode 31 and the second metal electrode 32 are arranged in parallel, and the gap between the two sets of metal electrodes forms an electrode channel 33. The length-to-width ratio of the electrode channel 33 is 3~8:1; the length direction of the electrode channel 33 is parallel to the long side direction of the first metal electrode 31.

[0020] Furthermore, both the first metal electrode 31 and the second metal electrode 32 can be elongated strips, and the two sets of metal electrodes can be arranged in parallel; the gap between the two sets of metal electrodes forms an electrode channel 33. The ratio of the length L to the width W of the electrode channel 33 is set to 3~8:1; in a preferred embodiment, the ratio of the length L to the width W can be set to 4~6:1; in the optimal embodiment, the ratio of the length L to the width W can be set to 5:1; wherein the length direction of the electrode channel 33 is parallel to the long side direction of the metal electrode. For example, if the length of the electrode channel 33 is set to 1mm, then the length of the first metal electrode 31 and the second metal electrode 32 is also 1mm, and the width of the electrode channel 33 is set to 0.2mm, then the ratio of the length L to the width W of the electrode channel 33 is 5:1.

[0021] This application discloses a fabrication method in specific embodiments, wherein the fabrication method is used to prepare a detector based on N-doped and nanoparticle-doped amorphous oxide thin-film transistors as described in the above embodiments; please refer to... Figure 7 The preparation method includes steps S1 to S7.

[0022] S1. A silicon oxide wafer with heavily doped n-type polycrystalline silicon is used as the doped polycrystalline silicon substrate and cleaned. A silicon dioxide layer is attached to the upper surface of the heavily doped n-type polycrystalline silicon.

[0023] First, a silicon oxide wafer with heavily doped n-type polycrystalline silicon (n++Si) can be used as the doped polycrystalline silicon substrate to fabricate the bottom-gate top-contact device. Before the actual fabrication process, the doped polycrystalline silicon substrate can be cleaned. A silicon oxide layer is attached to the top surface of the heavily doped n-type polycrystalline silicon, and its specific structure is as follows: Figure 1 As shown.

[0024] In a specific embodiment, the step of cleaning the doped polycrystalline silicon substrate includes: sequentially performing ultrasonic cleaning of the doped polycrystalline silicon substrate with DECON-90 cleaning agent, ultrasonic cleaning with ethanol, and ultrasonic cleaning with deionized water; and drying the doped polycrystalline silicon substrate at 90~135°C for 1.5~3 hours to remove surface moisture.

[0025] The doped polycrystalline silicon substrate is ultrasonically cleaned sequentially using DECON-90 cleaning agent, ultrasonically cleaned with ethanol, and ultrasonically cleaned with deionized water. The ultrasonically cleaned doped polycrystalline silicon substrate is then dried at 90~135℃ for 1.5~3 hours to remove surface moisture. In a preferred embodiment, the drying temperature can be set to 120℃ and the drying time to 2 hours.

[0026] S2. A metal thin film is thermally evaporated on the silicon dioxide layer of the doped polycrystalline silicon substrate, and then annealed at 320~460°C for 1.5~3 minutes to form metal nanoparticles.

[0027] Furthermore, a metal thin film is thermally evaporated onto the silicon dioxide layer of a doped polycrystalline silicon substrate. For example, a 5 nm thick silver metal thin film can be thermally evaporated onto the silicon dioxide layer. Afterward, the doped polycrystalline silicon substrate is annealed at 320–460 °C for 1.5–3 minutes. During annealing, the metal in the thin film agglomerates and forms metal nanoparticles. The flattened metal nanoparticles after cooling constitute the metal nanofilm. In a preferred embodiment, the doped polycrystalline silicon substrate can be annealed at 400 °C for 2 minutes.

[0028] S3. Amorphous indium gallium zinc oxide thin film is deposited on the silicon dioxide layer by magnetron sputtering through a mask, and an argon / nitrogen mixed gas is introduced during the sputtering process.

[0029] Subsequently, an amorphous indium gallium zinc oxide (IGaZO) thin film is deposited on the surface of the silicon dioxide layer by magnetron sputtering using a mask. The thickness of the IGaZO thin film can be 20 nm. During the sputtering deposition process, an argon / nitrogen mixed gas is introduced to achieve N doping during the deposition of the IGaZO thin film. In this case, the sputtered deposition results in an N-doped IGaZO thin film.

[0030] In a specific embodiment, the magnetron sputtering power is 65~100W, and the target atomic ratio is In:Ga:Zn = 1:1:1. Specifically, the flow rates of argon and nitrogen in the mixed gas are 28.5 sccm: 3.5~6 sccm.

[0031] The magnetron sputtering power can be set to 65~100W, and in a preferred embodiment, the sputtering power can be set to 80W. The target atomic ratio is In:Ga:Zn = 1:1:1. Furthermore, to improve the N doping effect, the flow rates of argon and nitrogen in the mixed gas can be set to 28.5 sccm:3.5~6 sccm, and in a preferred embodiment, the flow rates of argon and nitrogen are set to 28.5 sccm:4.5 sccm.

[0032] In existing technologies, the sputtering atmosphere for amorphous indium gallium zinc oxide (IGaZN) thin films is a mixture of argon and oxygen. Argon is used to ionize into argon ions, which bombard the target material, causing surface target atoms to detach and completing the sputtering process. Oxygen is used to replenish oxygen atoms and fill oxygen vacancies. However, in the preparation method of this application, O2 is completely replaced with N2 during sputtering deposition, and no oxygen is used during the sputtering process. Since the diameter of O atoms is not significantly different from that of N atoms, N atoms will substitute for O and bond with the metal. Simultaneously, due to the oxygen-deficient environment during sputtering, oxygen vacancies are generated within the thin film. The substituted N atoms and the generated oxygen vacancies will have different effects.

[0033] S4. Repeat the above steps of thermal evaporation and magnetron sputtering to obtain two stacked N-doped amorphous indium gallium zinc oxide films as active layers.

[0034] Repeating steps S2 to S3 above, another N-doped amorphous indium gallium zinc oxide (IGaZO) film is formed on top of the first N-doped IGaZO film. The resulting two stacked N-doped IGaZO films serve as the active layer. Each IGaZO film has a metal nanofilm on its side facing the silicon dioxide layer.

[0035] S5. Place the device with the active layer in a mixed atmosphere and anneal it at the first annealing temperature for 20-45 minutes; the mixed atmosphere is composed of nitrogen and oxygen.

[0036] The device with the active layer is further placed in a mixed atmosphere and annealed at a first annealing temperature for 20-45 minutes. In a preferred embodiment, the annealing time can be set to 30 minutes. The annealing process eliminates film stress in the amorphous indium gallium zinc oxide film and optimizes film defects. The annealing process is carried out in a mixed atmosphere composed of nitrogen and oxygen, such as setting the ratio of nitrogen to oxygen in the mixed atmosphere to be 4:1.

[0037] S6. A patterned first metal electrode and a second metal electrode are obtained by using a thermal evaporation method combined with a mask to deposit a metal thin film.

[0038] After annealing, a metal thin film is deposited using a thermal evaporation method combined with a photomask. If an aluminum metal thin film can be deposited in a specific area, each Al metal thin film can serve as a set of metal electrodes. The patterned first and second metal electrodes formed constitute the metal electrode layer. The thickness of the metal thin film can be set to 20-45 nm, and in a preferred embodiment, the thickness of the metal thin film can be set to 30 nm.

[0039] S7. Place the device containing the metal electrode back into the mixed atmosphere and anneal it at the second annealing temperature for 3 to 8 minutes to obtain the photodetector; the second annealing temperature is lower than the first annealing temperature.

[0040] Furthermore, the device containing the metal electrodes is placed again in the same mixed atmosphere as in step S5, and annealed at the second annealing temperature for 3-8 minutes to obtain a photodetector; in a preferred embodiment, the annealing time can be set to 5 minutes. The second annealing temperature can be set to be lower than the first annealing temperature.

[0041] In a specific embodiment, the first annealing temperature is 220~300℃, and the second annealing temperature is 175~240℃.

[0042] Specifically, the first annealing temperature can be set to 220~300℃, and the second annealing temperature can be set to 175~240℃; in a preferred embodiment, the first annealing temperature can be set to 250℃, and the second annealing temperature can be set to 200℃.

[0043] The technical method of this application also improves the nanoparticle size and film quality, and explores the optimal fabrication process of this photodetector, thereby achieving a better performance-yield balance between light absorption gain and film coverage quality.

[0044] For comparative testing, this application used several different structures during the testing process, including those with and without bilayer nanoparticles and those with and without N doping in the amorphous indium gallium zinc oxide film. Figure 3 As shown, Figure 3 Figure (c) shows a photoelectric sensor containing a double-layer nanofilm and an amorphous indium gallium zinc oxide film doped with N, prepared according to the above preparation method. This photoelectric sensor is an embodiment of this scheme. Figure 3 Figure (a) shows the device as a comparative example 1, in which the double-layer nanofilm is removed from the example and the amorphous indium gallium zinc oxide film is not doped with N. Figure 3 Figure (b) shows a device based on the embodiment, using an amorphous indium gallium zinc oxide thin film without N doping, which serves as Comparative Example 2.

[0045] Different voltages were applied to the devices in Comparative Example 1, Comparative Example 2, and the embodiment, and the changes in current of the devices were measured. The test results obtained are as follows: Figure 4 As shown, where, Figure 4 (a) Corresponding ratio 1, Figure 4 (b) Corresponding ratio 2, Figure 4 (c) Corresponding embodiment. Vertical axis I DS Represents drain current, x-axis V GS Indicates the gate voltage. (By...) Figure 4 It can be seen that amorphous indium gallium zinc oxide films under conventional sputtering atmosphere (Ar+O2) readily react with air to produce oxygen absorption / desorption effects, which leads to a certain hysteresis effect. However, nitrogen atoms form more stable metal-nitrogen bonds than oxygen atoms, thus reducing the hysteresis effect in darkness. It can be observed that doping with nanoparticle structures in the embodiments increases the device hysteresis effect, while doping with nitrogen in the amorphous indium gallium zinc oxide film repairs this effect. Therefore, compared to the two comparative examples, the embodiments in this application can reduce the hysteresis effect of the photodetector, thereby improving the device's operational stability.

[0046] Since the bandgap of undoped intrinsic amorphous indium gallium zinc oxide (IGaZO) films is typically greater than 3.2 eV (corresponding to a cutoff wavelength of approximately 385 nm), they only respond to ultraviolet light, and may exhibit a weak response at the ultraviolet-visible boundary due to band tail states. During the sputtering fabrication of amorphous IGaZO films in a nitrogen atmosphere, the concentration of oxygen vacancies (Vo) within the film is significantly increased. These oxygen vacancies form sub-bandgap states within the bandgap. When the N2-treated device is exposed to visible light, these sub-bandgap states greatly increase the probability of excited electron transitions, facilitating photon absorption and exciting electrons from oxygen vacancies into the conduction band, while the oxygen vacancies are converted into Vo states. 2+ This leads to an increase in the flow of charge carriers in the conduction band, thereby increasing the carrier concentration in the channel of the amorphous indium gallium zinc oxide thin film under illumination.

[0047] Meanwhile, the pre-annealing atmosphere (annealing treatment at the first annealing temperature) is also related to the N-doping process in this application. If pre-annealing is performed in pure nitrogen, the carrier concentration will continue to rise, causing the device to fail to turn off. If pre-annealing is performed in pure oxygen, excessive O atoms will re-enter the amorphous indium gallium zinc oxide film to fill oxygen vacancies, causing the photoresponse effect to disappear. However, actual tests showed that annealing in an atmosphere with an N2:O2 ratio of 4:1 preserved the photoresponse and did not cause problems with device turn-off.

[0048] Therefore, the core of the N-doping process lies in adjusting the atmosphere during sputtering to argon and nitrogen. Since excessively high nitrogen flow rates can significantly reduce the quality of the sputtered film, the argon-to-nitrogen flow rate is 28.5 sccm:4.5 sccm. Multi-wavelength response tests were performed on Comparative Example 1, Comparative Example 2, and the examples. The test results are as follows: Figure 5 and Figure 6 As shown, Figure 5 Mid-horizontal axis V GS Represents gate voltage, vertical axis I DS Indicates drain current. Figure 5 The medium curve is also the transfer characteristic curve of the device under different illumination conditions; Figure 6 The horizontal axis represents wavelength, and the vertical axis D * This represents the specific detectivity. The higher the specific detectivity value, the stronger the detector's ability to detect weak signals. Figure 5 (a) Corresponding ratio 1, Figure 5 (b) Corresponding ratio 2, Figure 5 In embodiment (c), Dark represents the test curve under no-light conditions. The tests show that doping amorphous indium gallium zinc oxide thin films with N improves the photoresponse in the 360-700 nm wavelength range compared to the comparative example; the embodiments of this application exhibit a significant advantage in photoresponse within the 450-700 nm wavelength range.

[0049] This invention provides a detector based on an amorphous oxide thin-film transistor (TIV) doped with N and nanoparticles. The photodetector includes a doped polycrystalline silicon substrate, an active layer, and a metal electrode layer stacked sequentially. The doped polycrystalline silicon substrate includes a stacked silicon dioxide layer and heavily doped n-type polycrystalline silicon. The silicon dioxide layer is disposed in close proximity to the active layer. The active layer includes at least two N-doped amorphous indium gallium zinc oxide (IGaZO) thin films. A metal nanofilm is disposed on the side of the IGaZO thin film facing the silicon dioxide layer. The metal nanofilm is formed by the planar deposition of metal nanoparticles. The metal electrode layer includes a patterned first metal electrode and a second metal electrode, with a gap between the first and second metal electrodes. This photodetector constructs a double-layer metal nanofilm at the interface of the insulating layer and within the active layer. By setting two layers of amorphous IGaZO thin films and introducing N doping, the oxygen vacancy concentration in the active layer is effectively increased. This not only expands the photoresponse range but also further excites carriers in the channel, thereby enhancing the visible light response characteristics of the device. It improves the detectivity and expands the detection range, while also enhancing the device's operational stability. The aforementioned photodetector can be applied to flexible, large-area, low-cost optical detection fields, as well as broadband ultraviolet-visible light detection fields.

[0050] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A detector based on an amorphous oxide thin-film transistor doped with N and nanoparticles, characterized in that, The photodetector comprises a doped polycrystalline silicon substrate, an active layer, and a metal electrode layer stacked sequentially. The doped polycrystalline silicon substrate includes a stacked silicon dioxide layer and heavily doped n-type polycrystalline silicon; the silicon dioxide layer is disposed in close contact with the active layer; The active layer comprises at least two N-doped amorphous indium gallium zinc oxide thin films; a metal nanofilm is disposed on the side of the amorphous indium gallium zinc oxide thin film facing the silicon dioxide layer; the metal nanofilm is formed by laying metal nanoparticles flat. The metal electrode layer includes a patterned first metal electrode and a second metal electrode, with a gap between the first metal electrode and the second metal electrode.

2. The detector based on N-doped and nanoparticle-doped amorphous oxide thin-film transistor according to claim 1, characterized in that, The metal nanofilm is formed by spreading silver nanoparticles, and the thickness of the metal nanofilm is 5-15 nm.

3. The detector based on N-doped and nanoparticle-doped amorphous oxide thin-film transistor according to claim 2, characterized in that, The thickness of the single-layer amorphous indium gallium zinc oxide film is 15-40 nm.

4. The detector based on N-doped and nanoparticle-doped amorphous oxide thin-film transistors according to any one of claims 1-3, characterized in that, The thickness of the silicon dioxide layer in the doped polycrystalline silicon substrate is 60-200 nm.

5. The detector based on N-doped and nanoparticle-doped amorphous oxide thin-film transistors according to claim 4, characterized in that, The first metal electrode and the second metal electrode are arranged in parallel, and the gap between the two sets of metal electrodes forms an electrode channel. The length-to-width ratio of the electrode channel is 3 to 8:

1. The length direction of the electrode channel is parallel to the long side direction of the first metal electrode.

6. A preparation method, characterized in that, The preparation method is used to prepare a detector based on N and nanoparticle doping of an amorphous oxide thin-film transistor as described in any one of claims 1-5, the preparation method comprising: A silicon dioxide wafer with heavily doped n-type polycrystalline silicon is used as the doped polycrystalline silicon substrate and cleaned. A silicon dioxide layer is attached to the upper surface of the heavily doped n-type polycrystalline silicon. A metal thin film is thermally evaporated on the silicon dioxide layer of the doped polycrystalline silicon substrate, and then annealed at 320~460 °C for 1.5~3 minutes to form metal nanoparticles; Amorphous indium gallium zinc oxide thin films are deposited on the silicon dioxide layer by magnetron sputtering using a mask, with an argon / nitrogen mixed gas introduced during the sputtering process. Repeat the above steps of thermal evaporation and magnetron sputtering to obtain two stacked N-doped amorphous indium gallium zinc oxide films as active layers; The device with the active layer is placed in a mixed atmosphere and annealed at a first annealing temperature for 20-45 minutes; the mixed atmosphere is composed of a mixture of nitrogen and oxygen. A patterned first metal electrode and a second metal electrode are obtained by thermal evaporation and metal thin film deposition using a mask. The device containing the metal electrodes is placed again in the mixed atmosphere and annealed at a second annealing temperature for 3 to 8 minutes to obtain the photodetector; the second annealing temperature is lower than the first annealing temperature.

7. The preparation method according to claim 6, characterized in that, The steps for cleaning the doped polycrystalline silicon substrate include: The doped polycrystalline silicon substrate was subjected to ultrasonic cleaning with DECON-90 cleaning agent, ultrasonic cleaning with ethanol, and ultrasonic cleaning with deionized water in sequence. The doped polycrystalline silicon substrate was dried at 90~135℃ for 1.5~3 hours to remove surface moisture.

8. The preparation method according to claim 6, characterized in that, The magnetron sputtering power is 65~100W, and the atomic ratio of the target material is In:Ga:Zn = 1:1:

1.

9. The preparation method according to claim 6, characterized in that, The flow rates of argon and nitrogen in the mixed gas are 28.5 sccm: 3.5~6 sccm.

10. The preparation method according to claim 6, characterized in that, The first annealing temperature is 220~300℃, and the second annealing temperature is 175~240℃.

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