Preparation method of NiN type two-dimensional heterojunction infrared photodetector

Abstract

The application relates to the technical field of photoelectric detectors, and specifically discloses a preparation method of a NiN type two-dimensional heterojunction infrared photoelectric detector. In view of the problem that the conventional architecture of an existing two-dimensional infrared detector is difficult to consider both dark current suppression and carrier transport efficiency, resulting in the fact that the detection sensitivity, response speed and photoelectric conversion efficiency of the device cannot be simultaneously improved, the core of the detector prepared by the application is an N-i-N heterostructure vertically stacked by ReS2 / 1T'-MoTe2 / WS2, and the preparation process comprises substrate pretreatment, two-dimensional material stripping and transferring and layer-by-layer stacking in an inert atmosphere, electrode patterning and evaporation, annealing treatment, and supporting in-situ phase state stabilization and interface passivation processes. By constructing a back-to-back double built-in electric field architecture, the application synchronously realizes dark current suppression and efficient separation of carriers, the prepared detector has excellent photoelectric performance, the process is simple and controllable, the compatibility with semiconductor processes is high, and the detector can be applied to the fields of intelligent sensing and biological imaging.

Description

Technical Field

[0001] This application relates to the field of photodetector technology, and more specifically, to a method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector. Background Technology

[0002] In the modern optoelectronic information industry, infrared photodetectors are core components for converting optical signals into electrical signals, and they have wide and irreplaceable applications in many fields such as military reconnaissance, environmental monitoring, biomedical imaging, optical communication, and autonomous driving. With the rapid iteration of next-generation information technology, the industry has placed increasingly higher demands on the miniaturization, room-temperature operation, detection sensitivity, response speed, and photoelectric conversion efficiency of infrared photodetectors. Novel infrared detection devices that combine structural simplicity and performance advantages have become an important research direction in the field of optoelectronics. Two-dimensional layered materials, represented by transition metal dichalcogenides, have become the core material system for constructing novel infrared photodetectors due to their atomically thin thickness, tunable band structure, and excellent photoelectric properties. Heterojunction photodetectors based on two-dimensional materials have also become an important technological path to overcome the performance bottlenecks of traditional devices.

[0003] Currently, infrared photodetectors based on two-dimensional materials mostly employ conventional PN junction, PIN junction, or Schottky junction architectures. In practical applications, these devices consistently face the core technical challenge of simultaneously suppressing dark current and improving carrier transport efficiency. Under conventional architectures, the barrier structures designed to suppress dark current often simultaneously hinder the separation and transport of photogenerated carriers, leading to a series of problems such as increased recombination losses of photogenerated electron-hole pairs, slower response speed, and decreased photoelectric conversion efficiency. On the other hand, optimizing carrier transport characteristics can easily result in increased dark current, reduced detection sensitivity, and difficulty in meeting the comprehensive performance requirements of high-performance infrared detection. Summary of the Invention

[0004] To address the problem that existing two-dimensional infrared photodetectors struggle to simultaneously suppress dark current and improve carrier transport efficiency, which can limit device photoelectric conversion efficiency and response speed, this application provides a method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector.

[0005] A method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector includes the following steps:

[0006] S1. Substrate cleaning and pretreatment: The substrate is ultrasonically cleaned to remove surface contaminants. After cleaning, the surface is dried with inert gas and then heated to remove residual moisture.

[0007] S2 and ReS2 contact layer transfer: Under an inert gas protective environment, a combination of mechanical peeling and dry transfer technology is used to transfer a few-layer rhenium disulfide material onto a pretreated substrate to form a bottom contact layer;

[0008] S3, 1T'-MoTe2 barrier layer transfer: Under the inert gas protection environment, a mechanical peeling method combined with dry transfer technology is used to transfer and stack the few-layer metallic phase molybdenum distellide material on the upper surface of the bottom contact layer to form an intermediate barrier absorption layer.

[0009] S4 and WS2 absorption layer transfer: Under the inert gas protection environment, a mechanical peeling method combined with dry transfer technology is used to transfer and stack a few layers of tungsten disulfide material on the upper surface of the intermediate barrier absorption layer to form a top absorption and collection layer, thereby constructing a NiN heterostructure with ReS2 / 1T'-MoTe2 / WS2 vertically stacked.

[0010] S5. Electrode patterning and evaporation: Photoresist is coated on the surface of the prepared heterojunction sample. The patterns of the source electrode and the drain electrode are defined by exposure and development technology. A metal layer is deposited in the pattern using a metal evaporation process to form the source electrode, which is electrically in contact with the bottom contact layer, and the drain electrode, which is electrically in contact with the top absorption and collection layer, respectively.

[0011] S6. Annealing and stabilization treatment: The device with the prepared electrodes is placed in a protective atmosphere for rapid annealing treatment.

[0012] By adopting the above technical solution and using a bottom-up, step-by-step fabrication process, the entire process of substrate pretreatment, heterojunction core structure construction, electrode patterning fabrication, and device annealing and stabilization is completed sequentially. This enables the controllable fabrication of ReS2 / 1T'-MoTe2 / WS2 vertically stacked structures, providing a complete and coherent process path for the formation of NiN-type back-to-back bandgap architectures. The entire process is based on mechanical lift-off and van der Waals integration techniques, is simple and controllable to operate, and has strong compatibility with existing semiconductor microfabrication processes, ensuring that the fabricated devices possess a stable structural foundation and repeatable optoelectronic performance.

[0013] Preferably, in step S1, the substrate is a P-type silicon wafer with a silicon dioxide dielectric layer on its surface; the ultrasonic cleaning is performed sequentially using acetone solution, isopropanol solution and deionized water, and after cleaning and drying in step S1, a heating dehydration treatment is performed.

[0014] By employing the above technical solution, using a P-type silicon wafer with a silicon dioxide dielectric layer on its surface as the device substrate, an atomically flat film-forming substrate can be provided for the transfer of two-dimensional materials. The silicon dioxide layer also provides insulation between the device and the silicon substrate, preventing leakage current interference. Simultaneously, a graded solvent ultrasonic cleaning process using acetone, isopropanol, and deionized water, combined with heated dehydration treatment, sequentially removes organic contaminants, solvent residues, particulate impurities, and adsorbed moisture from the substrate surface. This prevents interface impurities from causing wrinkles, bubbles, and poor adhesion during subsequent two-dimensional material transfer, ensuring the interface quality between the bottom contact layer and the substrate.

[0015] Preferably, in steps S2, S3, and S4, the transfer is performed using a dry transfer technique assisted by a polydimethylsiloxane carrier to complete the positioning and stacking.

[0016] By adopting the above technical solution, polydimethylsiloxane is used as a transfer carrier to realize the dry transfer of two-dimensional materials. By utilizing the flexibility of polydimethylsiloxane and its weak van der Waals interaction with two-dimensional materials, the precise positioning and layer-by-layer stacking of two-dimensional materials can be achieved with the help of a micro-alignment system without damaging the crystal structure of few-layer two-dimensional thin films. This ensures the alignment accuracy between each layer of thin film and provides reliable process support for the formation of high-quality interlayer interfaces in heterojunctions.

[0017] Preferably, in step S2, the rhenium disulfide material is a 2H phase n-type semiconductor; in step S3, the metallic phase molybdenum ditelluride material is a 1T' phase intrinsic semiconductor; and in step S4, the tungsten disulfide material is a 2H phase n-type semiconductor.

[0018] By adopting the above technical solution and selecting a three-layer two-dimensional material with specific crystal phase and conductivity type as the core functional layer of the device, the core architecture of NiN-type heterojunction can be accurately constructed. The 2H-phase n-type rhenium disulfide and tungsten disulfide on both sides, stacked with the 1T'-phase intrinsic molybdenum ditelluride in the middle, undergo electron migration due to the Fermi level difference, forming back-to-back built-in electric fields with opposite directions at the interfaces of the two heterojunctions. This provides an internal driving force for the efficient separation and directional transport of photogenerated carriers. Simultaneously, the matched stable crystal phases ensure the stable performance of the photoelectric properties of each layer, providing a stable material basis for the near-infrared light absorption and exciton dissociation processes of the device.

[0019] Preferably, in step S3, after the molybdenum ditelluride material is transferred and stacked, it is immediately subjected to in-situ phase stabilization treatment under an inert gas protective environment; the in-situ phase stabilization treatment adopts a low-energy argon plasma irradiation process, and step S4 is executed immediately after the treatment is completed.

[0020] By adopting the above technical solution, after the 1T'-MoTe2 thin film is transferred and stacked, it is immediately subjected to low-energy argon plasma irradiation in an inert atmosphere. The low-energy irradiation mode can stabilize the intrinsic crystal phase of 1T'-MoTe2 without destroying the integrity of the two-dimensional thin film crystal or affecting the interlayer bonding effect, suppress the crystal phase transformation problem that occurs in subsequent processes, ensure the stability of the band structure and intrinsic semiconductor characteristics of the intermediate barrier absorption layer, and thus maintain the stability of the heterojunction back-to-back band structure.

[0021] Preferably, in steps S2, S3, and S4, after each two-dimensional film is mechanically peeled off and before it is transferred and stacked to the target position, the upper surface of the ReS2 film, the upper and lower surfaces of the 1T'-MoTe2 film, and the lower surface of the WS2 film are subjected to in-situ passivation modification under an inert gas protection environment; the in-situ passivation modification is performed using a chalcogenide saturated gas phase passivation process, and the corresponding film is stacked and transferred immediately after the passivation is completed.

[0022] By adopting the above technical solution, after the mechanical peeling of the two-dimensional thin film and before its transfer and stacking, the surfaces of each layer of material to be contacted to form the heterojunction interface are subjected to in-situ chalcogenide saturated gas-phase passivation treatment in an inert atmosphere. This passivation process is highly compatible with the chalcogenide two-dimensional material system, does not introduce foreign impurities, and can effectively passivate dangling bonds and defect sites on the material surface, reducing the formation of defect states at the heterojunction interface. At the same time, the entire process is isolated from water and oxygen, which can avoid oxidation and contamination of the material surface and interlayer interface, significantly improving the quality of the heterojunction interface and reducing the capture and non-radiative recombination losses of photogenerated carriers at the interface.

[0023] Preferably, in step S5, the photoresist is polymethyl methacrylate photoresist; the deposited metal layer is a chromium-gold stacked structure or a titanium-gold stacked structure.

[0024] By adopting the above technical solution, polymethyl methacrylate (PMMA) is selected as the photoresist material. It has good film-forming properties and high resolution, and is compatible with electron beam lithography and ultraviolet lithography processes, enabling high-precision, high-fidelity patterning of source and drain electrodes. Simultaneously, a chromium-gold or titanium-gold stacked structure is used as the electrode material. Chromium and titanium act as adhesion layers, solving the problem of poor adhesion between the gold layer and the two-dimensional material / substrate, thus improving the stability of the electrode structure. The gold layer, as a conductive layer, can form a low-resistance ohmic contact with the two-dimensional semiconductor material, reducing carrier transport losses at the electrode contact and ensuring efficient collection of photocurrent.

[0025] Preferably, in step S5, after the metal vapor deposition process is completed, the sample is immersed in acetone stripping solution, and the residual photoresist and metal layer in the non-patterned area are removed by gentle fluid impact. After stripping, the sample is rinsed with isopropanol and deionized water in sequence, and then dried with inert gas.

[0026] By adopting the above technical solution, after the metal evaporation process is completed, a lift-off process using acetone as the stripping fluid is used in conjunction with gentle fluid impact to complete the electrode stripping. This can efficiently remove the photoresist in the non-patterned areas and the corresponding redundant metal layer, while avoiding physical damage to the two-dimensional heterojunction film and electrode pattern caused by hard contact operation. The graded rinsing step after stripping can thoroughly remove residual stripping fluid and impurities, ensuring the cleanliness of the device surface and preventing residual impurities from affecting the subsequent optoelectronic performance and stability of the device.

[0027] Preferably, in step S6, the rapid annealing process is carried out in a protective atmosphere of nitrogen or argon, and the furnace is allowed to cool naturally after annealing.

[0028] By adopting the above technical solution, rapid annealing in an inert protective atmosphere of nitrogen or argon can avoid oxidation and degradation of two-dimensional materials and metal electrodes during the annealing process. At the same time, the thermal effect of the annealing process can effectively release the internal stress generated during the thin film preparation process, promote atomic rearrangement at the interface between the metal electrode and the two-dimensional material, optimize the interface contact characteristics, reduce the contact resistance, and repair minor lattice defects generated during the preparation process, ultimately improving the consistency of the optoelectronic performance and the long-term working stability of the device.

[0029] Preferably, in steps S2 to S4, the ReS2 film, 1T'-MoTe2 film, and WS2 film are stacked in a bottom-up order; after each film is transferred, it is subjected to pressure holding and static treatment in the inert gas protection environment.

[0030] By adopting the above technical solution and strictly following the bottom-up, layer-by-layer stacking sequence of ReS2 thin film, 1T'-MoTe2 thin film, and WS2 thin film, the foundation for accurately constructing a NiN-type back-to-back bandgap architecture is established, ensuring the bandgap structure matching of the three functional layers and the stable realization of the device's operating mechanism. Simultaneously, after each thin film transfer is completed, a pressure-holding and static treatment is performed in an inert atmosphere. This promotes the full interaction of van der Waals forces between the upper and lower two-dimensional materials, removes residual trace gases and impurities from the interlayer, improves the contact tightness and uniformity between heterojunction layers, forms a high-quality van der Waals contact interface, and ensures the stability of interlayer carrier transport characteristics.

[0031] In summary, this application has the following beneficial effects:

[0032] 1. This application adopts a NiN heterojunction fabrication method with ReS2 / 1T'-MoTe2 / WS2 vertical stacking. By constructing a back-to-back dual built-in electric field band structure, it achieves efficient separation of photogenerated carriers and local confinement of holes, effectively suppresses dark current and photogenerated carrier recombination loss, and significantly improves the photoelectric conversion efficiency and response speed of infrared photodetectors.

[0033] 2. In this application, a dry transfer process with full inert gas protection is preferred. By performing in-situ passivation modification on the corresponding surfaces of the heterojunction interface before stacking each layer of thin film, the interface dangling bonds and defect states are effectively eliminated, the interface carrier trapping effect is suppressed, and the heterojunction interface bonding quality and long-term device stability are significantly improved.

[0034] 3. The method of this application involves in-situ phase stabilization treatment after the 1T'-MoTe2 thin film is transferred and stacked. The intrinsic properties of the 1T' phase of the material are stabilized by low-energy argon plasma irradiation process, which avoids crystal phase degradation and ensures the stable construction of the back-to-back built-in electric field and the efficient dissociation effect of photogenerated excitons.

[0035] 4. In this application, the preferred method is to use a layer-by-layer stacking pressure holding and static setting, adaptable metal electrode preparation and rapid annealing process, which can realize a high-quality van der Waals contact interface of heterojunction and low-resistance ohmic contact of electrode, optimize the carrier collection efficiency of device, and the preparation process is compatible with existing semiconductor processes, which is simple, controllable and highly repeatable. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the fabrication process of the NiN-type two-dimensional heterojunction infrared photodetector provided in the embodiments of this application;

[0037] Figure 2 This is a schematic diagram of the layered stacked structure of the NiN-type two-dimensional heterojunction infrared photodetector provided in the embodiments of this application;

[0038] Figure 3 These are Raman spectra of the two-dimensional material and heterojunction provided in the embodiments of this application, wherein:

[0039] (a) is the Raman spectrum of the ReS2 thin film;

[0040] (b) is the Raman spectrum of the 1T'-MoTe2 thin film;

[0041] (c) is the Raman spectrum of the WS2 thin film;

[0042] (d) is the Raman spectrum of the ReS2 / 1T'-MoTe2 / WS2 heterojunction. Detailed Implementation

[0043] The present application will be further described in detail below with reference to embodiments and comparative examples. Unless otherwise specified, the experimental methods used below are conventional methods. Unless otherwise specified, the materials, reagents, methods and instruments used are all conventional materials, reagents, methods and instruments in the art, which can be obtained by those skilled in the art through commercial channels or prepared according to literature methods.

[0044] Technical Concept: Infrared photodetectors are core functional devices in optoelectronic information systems. With the rapid development of fields such as intelligent sensing, autonomous driving, and biomedical imaging, the demand for infrared detectors that combine high sensitivity, fast response, and miniaturization at room temperature is becoming increasingly urgent. Two-dimensional layered transition metal chalcogenides, with their atomically thin thickness, tunable band structure, and excellent photoelectric coupling properties, have become a core research and development direction for novel infrared detectors. Currently, infrared detectors based on two-dimensional materials mostly adopt conventional architectures such as PN junctions, PIN junctions, or Schottky junctions, which present an inherent contradiction between suppressing dark current and improving carrier transport efficiency: the barrier design for suppressing dark current hinders carrier separation and transport, exacerbates recombination losses, and reduces response speed and photoelectric conversion efficiency; while the low barrier design for optimizing carrier transport leads to increased dark current and decreased detection sensitivity, failing to meet the comprehensive requirements of high-performance infrared detection.

[0045] This technical solution addresses the aforementioned inherent contradictions by constructing a heterojunction architecture that balances dark current suppression and efficient carrier transport. It employs a NiN-type heterojunction design with ReS2 / 1T'-MoTe2 / WS2 vertically stacked structures. Through band matching, it creates back-to-back built-in electric fields with opposite directions at the heterojunction interface. Simultaneously, an inert atmosphere protection fabrication process ensures the stability of the heterocrystalline phase and interface quality. In the dark state, the dual built-in electric field barriers effectively block thermally excited carriers, suppressing dark current. Under illumination, the dual built-in electric fields synergistically drive efficient carrier separation, combined with hole localization effects to suppress carrier recombination, simultaneously improving device response speed and photoelectric conversion efficiency. This fundamentally resolves the core contradictions of existing technologies.

[0046] Example 1: This example provides a method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector. The specific steps are as follows:

[0047] S1. Substrate cleaning and pretreatment: The substrate is ultrasonically cleaned to remove surface contaminants. After cleaning, the surface is dried with inert gas and then heated to remove residual moisture.

[0048] The substrate is a P-type silicon wafer with a silicon dioxide dielectric layer on its surface, and the thickness of the silicon dioxide dielectric layer is 300nm. Ultrasonic cleaning is performed sequentially using acetone solution, isopropanol solution and deionized water, with each solvent having an ultrasonic cleaning time of 20min. After cleaning and drying, a heating dehydration treatment is performed. The heating dehydration treatment temperature is 125℃ and the heating time is 9min. High-purity nitrogen is used as the inert gas.

[0049] S2 and ReS2 contact layer transfer: Under an inert gas protective environment, a combination of mechanical peeling and dry transfer technology is used to transfer a few-layer rhenium disulfide material onto a pretreated substrate to form a bottom contact layer.

[0050] The inert gas protection environment was a nitrogen glove box atmosphere with both water and oxygen content below 0.1 ppm. Mechanical peeling was used to peel off the rhenium disulfide bulk material using blue film tape to prepare a few-layer rhenium disulfide film, which was then transferred to a polydimethylsiloxane carrier. Dry transfer technology used the polydimethylsiloxane carrier to assist in positioning and stacking. The rhenium disulfide material was a 2H phase n-type semiconductor, and the film thickness was controlled to 6 layers. After the rhenium disulfide film was mechanically peeled off and before being transferred and stacked onto the substrate, the process was carried out in a nitrogen glove box atmosphere. The upper surface of the rhenium disulfide thin film was subjected to in-situ passivation modification. The in-situ passivation modification was carried out using a saturated gas phase passivation process of chalcogen elements at a processing temperature of 32.5℃ and a single surface processing time of 15s, forming a single-atom-level passivation modification layer with a thickness of 0.4nm on the material surface. After the passivation treatment was completed, the stacking and transfer operation was performed immediately. After the film was transferred, it was subjected to pressure holding and static treatment in a nitrogen glove box atmosphere for 17.5s. During the process, the substrate temperature was kept stable at 25℃ to ensure the formation of a high-quality van der Waals contact interface between the layers.

[0051] S3, 1T'-MoTe2 barrier layer transfer: Under an inert gas protective environment, a combination of mechanical exfoliation and dry transfer technology is used to transfer and stack the few-layer metallic phase molybdenum distellide material onto the upper surface of the bottom contact layer to form an intermediate barrier absorption layer.

[0052] The inert gas protection environment was a nitrogen glove box atmosphere with both water and oxygen content below 0.1 ppm. Mechanical peeling was used to peel off the 1T'-MoTe2 bulk material using blue film tape to prepare a few-layer molybdenum ditelluride film, which was then transferred to a polydimethylsiloxane carrier. Dry transfer technology used the polydimethylsiloxane carrier to assist in positioning and stacking. The metallic phase molybdenum ditelluride material was a 1T' phase intrinsic semiconductor, and the film thickness was controlled at 9 layers. After mechanical peeling and before transfer and stacking to the bottom contact layer, in-situ passivation modification was performed on the upper and lower surfaces of the molybdenum ditelluride film in a nitrogen glove box atmosphere. The in-situ passivation modification used a chalcogenide saturated vapor phase passivation process at a processing temperature of 32.5℃. The single-surface treatment lasted 15 s, forming a 0.4 nm thick atomic-level passivation modification layer on the material surface. Immediately after passivation, the stacking and transfer operation was performed. After the film was transferred and stacked, it was immediately subjected to in-situ phase stabilization treatment in a nitrogen glove box atmosphere. The in-situ phase stabilization treatment adopted a low-energy argon plasma irradiation process with an irradiation energy of 7.5 eV, an irradiation time of 20 s, and an irradiation dose of 5.5 × 10¹² ions / cm². Immediately after the treatment, the subsequent WS2 film transfer operation was performed. After the film transfer was completed, a pressure holding and static treatment was performed in a nitrogen glove box atmosphere for 17.5 s. During the process, the substrate temperature was stabilized at 25 °C to ensure the formation of a high-quality van der Waals contact interface between the layers.

[0053] S4 and WS2 absorption layer transfer: Under an inert gas protective environment, a combination of mechanical exfoliation and dry transfer technology is used to transfer and stack a few layers of tungsten disulfide material on the upper surface of the intermediate barrier absorption layer to form a top absorption and collection layer, thus constructing a NiN heterostructure with ReS2 / 1T'-MoTe2 / WS2 vertically stacked.

[0054] The inert gas protection environment was a nitrogen glove box atmosphere with both water and oxygen content below 0.1 ppm. Mechanical exfoliation was used to peel off the tungsten disulfide bulk material using blue adhesive tape to prepare a few-layer tungsten disulfide film, which was then transferred to a polydimethylsiloxane carrier. Dry transfer technology used the polydimethylsiloxane carrier to assist in positioning and stacking. The tungsten disulfide material was a 2H phase n-type semiconductor, and the film thickness was controlled to 6 layers. After the mechanical exfoliation of the tungsten disulfide film and before its transfer and stacking to the intermediate barrier absorption layer, the process was carried out in a nitrogen glove box atmosphere. In-situ passivation modification was performed on the lower surface of the tungsten disulfide film. The in-situ passivation modification was performed using a saturated vapor phase passivation process with chalcogen elements at a processing temperature of 32.5℃ and a single-surface processing time of 15s, forming a single-atom-level passivation modification layer with a thickness of 0.4nm on the material surface. Immediately after the passivation treatment was completed, the stacking and transfer operation was performed. After the film transfer was completed, a pressure holding and static treatment was performed in a nitrogen glove box atmosphere for 17.5s. During the process, the substrate temperature was kept stable at 25℃ to ensure the formation of a high-quality van der Waals contact interface between the layers.

[0055] S5. Electrode Patterning and Evaporation: Photoresist is coated on the surface of the prepared heterojunction sample. The patterns of the source electrode and the drain electrode are defined by exposure and development technology. A metal layer is deposited in the pattern using a metal evaporation process to form the source electrode, which is electrically in contact with the bottom contact layer, and the drain electrode, which is electrically in contact with the top absorption and collection layer.

[0056] The photoresist is polymethyl methacrylate (PMMA) photoresist, and the thickness of the photoresist layer after spin coating is 400 nm. The exposure and development technology adopts electron beam exposure technology. The metal evaporation process adopts electron beam evaporation technology. The deposited metal layer is a chromium-gold stacked structure, in which the chromium adhesion layer is 5.5 nm thick and the gold conductive layer is 65 nm thick. After the metal evaporation process is completed, a lift-off electrode stripping step is also included, in which the sample is immersed in acetone stripping solution and gently purged with fluid to remove residual photoresist and metal layers in non-patterned areas. After stripping, the sample is rinsed with isopropanol and deionized water in sequence, and then dried with high-purity nitrogen.

[0057] S6. Annealing and stabilization treatment: The device with the prepared electrodes is placed in a protective atmosphere for rapid annealing treatment.

[0058] The rapid annealing process is carried out in a protective atmosphere of high-purity nitrogen, with an annealing temperature of 200℃ and a holding time of 300s. After annealing, the furnace is allowed to cool naturally to room temperature.

[0059] Example 2: This example provides a method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector. The specific steps are as follows:

[0060] S1. Substrate cleaning and pretreatment: The substrate is ultrasonically cleaned to remove surface contaminants. After cleaning, the surface is dried with inert gas and then heated to remove residual moisture.

[0061] The substrate is a P-type silicon wafer with a silicon dioxide dielectric layer on its surface, and the thickness of the silicon dioxide dielectric layer is 280nm. Ultrasonic cleaning is performed sequentially using acetone solution, isopropanol solution and deionized water, with each solvent having an ultrasonic cleaning time of 10min. After cleaning and drying, a heating dehydration treatment is performed. The heating dehydration treatment temperature is 100℃ and the heating time is 3min. High-purity nitrogen is used as the inert gas.

[0062] S2 and ReS2 contact layer transfer: Under an inert gas protective environment, a combination of mechanical peeling and dry transfer technology is used to transfer a few-layer rhenium disulfide material onto a pretreated substrate to form a bottom contact layer.

[0063] The inert gas protection environment was a nitrogen glove box atmosphere with both water and oxygen content below 0.1 ppm. Mechanical peeling was used to peel off the rhenium disulfide bulk material using blue adhesive tape to prepare a few-layer rhenium disulfide film, which was then transferred to a polydimethylsiloxane carrier. Dry transfer technology used the polydimethylsiloxane carrier to assist in positioning and stacking. The rhenium disulfide material was a 2H phase n-type semiconductor, and the film thickness was controlled to be 2 layers. After the rhenium disulfide film was mechanically peeled off and before being transferred and stacked onto the substrate, a nitrogen glove box atmosphere was used. Inside, the upper surface of the rhenium disulfide thin film was subjected to in-situ passivation modification. The in-situ passivation modification was carried out using a saturated gas phase passivation process of chalcogen elements at a processing temperature of 25°C and a single surface processing time of 10s, forming a single-atom-level passivation modification layer with a thickness of 0.3nm on the material surface. After the passivation treatment was completed, the stacking and transfer operation was performed immediately. After the film was transferred, it was subjected to pressure holding and static treatment in a nitrogen glove box atmosphere for 5s. During the process, the substrate temperature was stabilized at 20°C to ensure the formation of a high-quality van der Waals contact interface between the layers.

[0064] S3, 1T'-MoTe2 barrier layer transfer: Under an inert gas protective environment, a combination of mechanical exfoliation and dry transfer technology is used to transfer and stack the few-layer metallic phase molybdenum distellide material onto the upper surface of the bottom contact layer to form an intermediate barrier absorption layer.

[0065] The inert gas protection environment was a nitrogen glove box atmosphere with both water and oxygen content below 0.1 ppm. Mechanical peeling was used to peel the 1T'-MoTe2 bulk material using blue film tape to prepare a few-layer molybdenum ditelluride film, which was then transferred to a polydimethylsiloxane carrier. Dry transfer technology used the polydimethylsiloxane carrier to assist in positioning and stacking. The metallic phase molybdenum ditelluride material was a 1T' phase intrinsic semiconductor, and the film thickness was controlled to 3 layers. After mechanical peeling and before transfer and stacking to the bottom contact layer, in-situ passivation modification was performed on the upper and lower surfaces of the molybdenum ditelluride film in a nitrogen glove box atmosphere. The in-situ passivation modification used a chalcogenide saturated vapor phase passivation process at a processing temperature of 2°C. At 5℃, a single-surface treatment time of 10s was used to form a 0.3nm thick atomic-level passivation modification layer on the material surface. Immediately after passivation, the stacking and transfer operation was performed. After the film was transferred and stacked, it was immediately subjected to in-situ phase stabilization treatment in a nitrogen glove box atmosphere. The in-situ phase stabilization treatment adopted a low-energy argon plasma irradiation process with an irradiation energy of 5eV, an irradiation time of 10s, and an irradiation dose of 1×10¹²ions / cm². Immediately after the treatment, the subsequent WS2 film transfer operation was performed. After the film transfer was completed, a pressure holding and static treatment was performed in a nitrogen glove box atmosphere for 5s. During the process, the substrate temperature was stabilized at 20℃ to ensure the formation of a high-quality van der Waals contact interface between the layers.

[0066] S4 and WS2 absorption layer transfer: Under an inert gas protective environment, a combination of mechanical exfoliation and dry transfer technology is used to transfer and stack a few layers of tungsten disulfide material on the upper surface of the intermediate barrier absorption layer to form a top absorption and collection layer, thus constructing a NiN heterostructure with ReS2 / 1T'-MoTe2 / WS2 vertically stacked.

[0067] The inert gas protection environment was a nitrogen glove box atmosphere with both water and oxygen content below 0.1 ppm. Mechanical exfoliation was used to peel off the tungsten disulfide bulk material using blue adhesive tape to prepare a few-layer tungsten disulfide film, which was then transferred to a polydimethylsiloxane carrier. Dry transfer technology used the polydimethylsiloxane carrier to assist in positioning and stacking. The tungsten disulfide material was a 2H phase n-type semiconductor, and the film thickness was controlled to two layers. After the mechanical exfoliation of the tungsten disulfide film and before its transfer and stacking to the intermediate barrier absorption layer, a nitrogen glove box atmosphere was used. Within the scope, the lower surface of the tungsten disulfide film was subjected to in-situ passivation modification. The in-situ passivation modification was carried out using a saturated gas phase passivation process with chalcogen elements. The processing temperature was 25℃ and the single-surface processing time was 10s, forming a single-atom-level passivation modification layer with a thickness of 0.3nm on the material surface. After the passivation treatment was completed, the stacking and transfer operation was performed immediately. After the film transfer was completed, the film was subjected to pressure holding and static treatment in a nitrogen glove box atmosphere for 5s. During the process, the substrate temperature was stabilized at 20℃ to ensure the formation of a high-quality van der Waals contact interface between the layers.

[0068] S5. Electrode Patterning and Evaporation: Photoresist is coated on the surface of the prepared heterojunction sample. The patterns of the source electrode and the drain electrode are defined by exposure and development technology. A metal layer is deposited in the pattern using a metal evaporation process to form the source electrode, which is electrically in contact with the bottom contact layer, and the drain electrode, which is electrically in contact with the top absorption and collection layer.

[0069] The photoresist is polymethyl methacrylate (PMMA) photoresist, and the thickness of the photoresist layer after spin coating is 300 nm. The exposure and development technology adopts electron beam exposure technology. The metal evaporation process adopts electron beam evaporation technology. The deposited metal layer is a chromium-gold stacked structure, in which the chromium adhesion layer is 3 nm thick and the gold conductive layer is 50 nm thick. After the metal evaporation process is completed, a lift-off electrode stripping step is also included, in which the sample is immersed in acetone stripping solution and gently purged with fluid to remove residual photoresist and metal layers in non-patterned areas. After stripping, the sample is rinsed with isopropanol and deionized water in sequence, and then dried with high-purity nitrogen.

[0070] S6. Annealing and stabilization treatment: The device with the prepared electrodes is placed in a protective atmosphere for rapid annealing treatment.

[0071] The rapid annealing process is carried out in a protective atmosphere of high-purity nitrogen, with an annealing temperature of 150℃ and a holding time of 200s. After annealing, the furnace is allowed to cool naturally to room temperature.

[0072] Example 3: This example provides a method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector. The specific steps are as follows:

[0073] S1. Substrate cleaning and pretreatment: The substrate is ultrasonically cleaned to remove surface contaminants. After cleaning, the surface is dried with inert gas and then heated to remove residual moisture.

[0074] The substrate is a P-type silicon wafer with a silicon dioxide dielectric layer on its surface, and the thickness of the silicon dioxide dielectric layer is 320nm. Ultrasonic cleaning is performed sequentially using acetone solution, isopropanol solution and deionized water, with each solvent's ultrasonic cleaning time being 30min. After cleaning and drying, a heating dehydration treatment is performed. The heating dehydration treatment temperature is 150℃ and the heating time is 15min. High-purity nitrogen is used as the inert gas.

[0075] S2 and ReS2 contact layer transfer: Under an inert gas protective environment, a combination of mechanical peeling and dry transfer technology is used to transfer a few-layer rhenium disulfide material onto a pretreated substrate to form a bottom contact layer.

[0076] The inert gas protection environment was a nitrogen glove box atmosphere with both water and oxygen content below 0.1 ppm. Mechanical peeling was used to peel off the rhenium disulfide bulk material using blue adhesive tape to prepare a few-layer rhenium disulfide film, which was then transferred to a polydimethylsiloxane carrier. Dry transfer technology used the polydimethylsiloxane carrier to assist in positioning and stacking. The rhenium disulfide material was a 2H phase n-type semiconductor, and the film thickness was controlled to 10 layers. After the rhenium disulfide film was mechanically peeled off and before being transferred and stacked onto the substrate, a nitrogen glove box atmosphere was used. Inside, the upper surface of the rhenium disulfide thin film is subjected to in-situ passivation modification. The in-situ passivation modification is carried out using a saturated gas phase passivation process of chalcogen elements, with a processing temperature of 40℃ and a single surface processing time of 20s, forming a single-atom-level passivation modification layer with a thickness of 0.5nm on the material surface. After the passivation treatment is completed, the stacking and transfer operation is performed immediately. After the film transfer is completed, the film is subjected to pressure holding and static treatment in a nitrogen glove box atmosphere for 30s. During the process, the substrate temperature is kept stable at 30℃ to ensure the formation of a high-quality van der Waals contact interface between the layers.

[0077] S3, 1T'-MoTe2 barrier layer transfer: Under an inert gas protective environment, a combination of mechanical exfoliation and dry transfer technology is used to transfer and stack the few-layer metallic phase molybdenum distellide material onto the upper surface of the bottom contact layer to form an intermediate barrier absorption layer.

[0078] The inert gas protection environment was a nitrogen glove box atmosphere with both water and oxygen content below 0.1 ppm. Mechanical peeling was used to peel the 1T'-MoTe2 bulk material using blue film tape to prepare a few-layer molybdenum ditelluride film, which was then transferred to a polydimethylsiloxane carrier. Dry transfer technology used the polydimethylsiloxane carrier to assist in positioning and stacking. The metallic phase molybdenum ditelluride material was a 1T' phase intrinsic semiconductor, and the film thickness was controlled at 15 layers. After mechanical peeling and before stacking the molybdenum ditelluride film to the bottom contact layer, in-situ passivation modification was performed on the upper and lower surfaces of the molybdenum ditelluride film in a nitrogen glove box atmosphere. The in-situ passivation modification used a chalcogenide saturated vapor phase passivation process at a processing temperature of 4°C. At 0℃, a single-surface treatment time of 20s was used to form a 0.5nm thick atomic-level passivation modification layer on the material surface. Immediately after passivation, the stacking and transfer operation was performed. After the film was transferred and stacked, in-situ phase stabilization treatment was performed in a nitrogen glove box atmosphere. The in-situ phase stabilization treatment adopted a low-energy argon plasma irradiation process with an irradiation energy of 10eV, an irradiation time of 30s, and an irradiation dose of 1×10¹³ ions / cm². Immediately after the treatment, the subsequent WS2 film transfer operation was performed. After the film transfer was completed, a pressure holding and static treatment was performed in a nitrogen glove box atmosphere for 30s. During the process, the substrate temperature was stabilized at 30℃ to ensure the formation of a high-quality van der Waals contact interface between the layers.

[0079] S4 and WS2 absorption layer transfer: Under an inert gas protective environment, a combination of mechanical exfoliation and dry transfer technology is used to transfer and stack a few layers of tungsten disulfide material on the upper surface of the intermediate barrier absorption layer to form a top absorption and collection layer, thus constructing a NiN heterostructure with ReS2 / 1T'-MoTe2 / WS2 vertically stacked.

[0080] The inert gas protection environment was a nitrogen glove box atmosphere with both water and oxygen content below 0.1 ppm. Mechanical exfoliation was used to peel off the tungsten disulfide bulk material using blue adhesive tape to prepare a few-layer tungsten disulfide film, which was then transferred to a polydimethylsiloxane carrier. Dry transfer technology used the polydimethylsiloxane carrier to assist in positioning and stacking. The tungsten disulfide material was a 2H phase n-type semiconductor, and the film thickness was controlled to 10 layers. After the mechanical exfoliation of the tungsten disulfide film and before its transfer and stacking to the intermediate barrier absorption layer, a nitrogen glove box atmosphere was used. Within the scope, the lower surface of the tungsten disulfide film was subjected to in-situ passivation modification. The in-situ passivation modification was carried out using a saturated gas phase passivation process with chalcogen elements at a processing temperature of 40℃ and a single-surface processing time of 20s, forming a single-atom-level passivation modification layer with a thickness of 0.5nm on the material surface. Immediately after the passivation treatment was completed, the stacking and transfer operation was performed. After the film transfer was completed, a pressure holding and static treatment was carried out in a nitrogen glove box atmosphere for 30s. During the process, the substrate temperature was kept stable at 30℃ to ensure the formation of a high-quality van der Waals contact interface between the layers.

[0081] S5. Electrode Patterning and Evaporation: Photoresist is coated on the surface of the prepared heterojunction sample. The patterns of the source electrode and the drain electrode are defined by exposure and development technology. A metal layer is deposited in the pattern using a metal evaporation process to form the source electrode, which is electrically in contact with the bottom contact layer, and the drain electrode, which is electrically in contact with the top absorption and collection layer.

[0082] The photoresist is polymethyl methacrylate (PMMA) photoresist, and the thickness of the photoresist layer after spin coating is 500 nm. The exposure and development technology adopts electron beam exposure technology. The metal evaporation process adopts electron beam evaporation technology. The deposited metal layer is a chromium-gold stacked structure, in which the chromium adhesion layer is 8 nm thick and the gold conductive layer is 80 nm thick. After the metal evaporation process is completed, a lift-off electrode stripping step is also included, in which the sample is immersed in acetone stripping solution and gently purged with fluid to remove residual photoresist and metal layers in non-patterned areas. After stripping, the sample is rinsed with isopropanol and deionized water in sequence, and then dried with high-purity nitrogen.

[0083] S6. Annealing and stabilization treatment: The device with the prepared electrodes is placed in a protective atmosphere for rapid annealing treatment.

[0084] The rapid annealing process is carried out in a protective atmosphere of high-purity nitrogen, with an annealing temperature of 250℃ and a holding time of 400s. After annealing, the furnace is allowed to cool naturally to room temperature.

[0085] The core structure, working mechanism, characterization method, and expected performance of the NiN-type two-dimensional heterojunction infrared photodetector prepared according to the methods described in Examples 1-3 above are as follows:

[0086] I. Core Structure of the Device

[0087] The overall structure of the infrared photodetector prepared by this invention is as follows: Figure 2 As shown, from bottom to top, the structure includes a SiO2 / Si substrate, a ReS2 bottom contact layer, a 1T'-MoTe2 intermediate barrier absorption layer, a WS2 top absorption and collection layer, and source electrodes forming ohmic contacts with ReS2 and drain electrodes forming ohmic contacts with WS2, ultimately forming a vertically stacked ReS2 / 1T'-MoTe2 / WS2 van der Waals heterojunction core architecture. This structure is based on a back-to-back NiN bandgap architecture design, completely different from the conventional PN junction and PIN junction architectures of traditional photodetectors, providing a novel device structure solution for high-performance near-infrared detection.

[0088] II. Working Principle of the Device

[0089] The ReS2 / 1T'-MoTe2 / WS2 vertical van der Waals heterostructure of this invention achieves high-performance near-infrared photoelectric detection based on the NiN back-to-back bandgap architecture. The core working principle is as follows:

[0090] When n-type ReS2 and n-type WS2 come into contact with intrinsic i-type 1T'-MoTe2, electrons migrate from the higher Fermi level n-type layer to the i-type layer, eventually forming back-to-back built-in electric fields with opposite directions at the ReS2 / 1T'-MoTe2 and 1T'-MoTe2 / WS2 interfaces.

[0091] When near-infrared light illuminates the device, the valence band electrons of the i-type 1T'-MoTe2, which serves as the core light-absorbing layer, absorb photon energy and transition to the conduction band, generating a large number of electron-hole pairs. The two sets of back-to-back built-in electric fields work together to efficiently separate the photogenerated carriers. Electrons are directionally transported to the n-type ReS2 and WS2 layers on both sides, while holes are confined within the i-type 1T'-MoTe2 layer in the middle, significantly suppressing the recombination loss of photogenerated carriers. Finally, the directionally moving electrons form a stable photocurrent. By detecting changes in the photocurrent through an external circuit, high-sensitivity and rapid detection of near-infrared light signals can be achieved.

[0092] Meanwhile, the type II band arrangement formed by the bottom ReS2 and the top WS2 can further promote the effective separation of holes, and work synergistically with the exciton dissociation effect of the middle layer to comprehensively improve the photoelectric conversion efficiency of the device.

[0093] III. Material and Device Characterization Methods

[0094] For the fabricated two-dimensional material thin films and heterojunction devices, the following characterization methods can be used to verify the material structure, heterojunction interface quality, and device fabrication effect:

[0095] Morphology and thickness characterization: Atomic force microscopy (AFM) was used to accurately measure the thickness and surface morphology of ReS2, 1T'-MoTe2, and WS2 monolayer films to confirm the preparation effect of few-layer films;

[0096] Microstructure and interface characterization: Transmission electron microscopy (TEM) was used to characterize the layered stacking structure and interlayer spacing of the heterojunction. At the same time, it was detected whether amorphous oxides were generated during the preparation of the heterojunction and whether there was contamination at the interface, thus verifying the interface quality of the heterojunction.

[0097] Material phase and structure characterization: Raman spectroscopy was used to test each single-layer two-dimensional material and the final stacked heterojunction to verify the crystal phase purity, structural integrity of each layer, and van der Waals coupling effect of the heterojunction.

[0098] IV. Characterization Results and Expected Performance

[0099] (I) Expected Results of Material and Structure Characterization

[0100] Raman spectroscopy results of ReS2, 1T'-MoTe2, WS2 monolayer materials and heterostructures are as follows: Figure 3 As shown, where:

[0101] The Raman spectrum of ReS2 is in ~ and ~ The presence of distinct characteristic peaks at the 2H phase confirms its high-purity structure.

[0102] Raman spectra of 1T'-MoTe2 in The region exhibits multiple characteristic peaks, which confirms the stable existence of its metallic 1T' phase and lays the material foundation for the efficient dissociation of photogenerated excitons in the device.

[0103] The Raman spectrum of WS2 is in ~ The presence of a strong characteristic peak at this location verifies the integrity of its crystal structure.

[0104] In the overall Raman spectrum of the heterojunction, the core characteristic peaks of each layer of the material are completely preserved. At the same time, slight peak position perturbations occur due to the interlayer van der Waals coupling, which proves that the ReS2 / 1T'-MoTe2 / WS2 van der Waals heterojunction has been successfully constructed. Furthermore, the crystal phase structure of each layer of the material did not degrade during the stacking process, providing reliable structural support for the high-performance photoelectric response of the device.

[0105] (II) Expected Effects of Device Optoelectronic Performance

[0106] Based on the NiN back-to-back heterojunction architecture of this invention, combined with the corresponding interface modulation and phase stabilization processes, the fabricated infrared photodetector can achieve the following core performance breakthroughs:

[0107] Achieving ultra-low dark current: In the dark state, the potential barrier formed by the back-to-back dual built-in electric fields can effectively block the diffusion and transport of thermally excited charge carriers, greatly suppressing the dark current of the device and solving the industry pain points of excessive dark current and limited detection sensitivity of traditional two-dimensional infrared detectors.

[0108] Achieving high-efficiency photoelectric conversion and fast response: The synergistic effect of the dual built-in electric fields can achieve efficient separation of photogenerated carriers, while the hole localization binding mechanism can significantly reduce the carrier recombination probability, thereby significantly improving the photoelectric conversion efficiency and response speed of the device.

[0109] It possesses excellent environmental stability and process compatibility: the entire process of inert atmosphere preparation, interface passivation modification, and rapid annealing can effectively ensure the heterojunction interface quality and device stability. Moreover, the entire process adopts mechanical stripping and van der Waals integration technology, which has good compatibility with existing semiconductor integrated circuit processes.

[0110] V. Application Value and Prospects

[0111] The method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector proposed in this invention has the advantages of simple process, low fabrication cost and high reproducibility. It breaks through the limitations of traditional infrared detectors, which require low temperature cooling, are bulky and expensive. At the same time, it solves the technical bottlenecks of conventional two-dimensional heterojunction detectors, such as high dark current, severe carrier recombination and limited response speed.

[0112] Based on its excellent near-infrared photoelectric detection performance, this device can be widely used in many fields such as military reconnaissance, environmental monitoring, biomedical imaging, optical communication, and autonomous driving. It provides core device solutions for a new generation of miniaturized, integrated, and high-performance infrared photoelectric systems, and has extremely high scientific research value and industrial application potential.

[0113] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector, characterized in that: Includes the following steps: S1. Substrate cleaning and pretreatment: The substrate is ultrasonically cleaned to remove surface contaminants. After cleaning, the surface is dried with inert gas and then heated to remove residual moisture. S2 and ReS2 contact layer transfer: Under an inert gas protective environment, a combination of mechanical peeling and dry transfer technology is used to transfer a few-layer rhenium disulfide material onto a pretreated substrate to form a bottom contact layer; S3, 1T'-MoTe2 barrier layer transfer: Under the inert gas protection environment, a mechanical peeling method combined with dry transfer technology is used to transfer and stack the few-layer metallic phase molybdenum distellide material on the upper surface of the bottom contact layer to form an intermediate barrier absorption layer. S4 and WS2 absorption layer transfer: Under the inert gas protection environment, a mechanical peeling method combined with dry transfer technology is used to transfer and stack a few layers of tungsten disulfide material on the upper surface of the intermediate barrier absorption layer to form a top absorption and collection layer, thereby constructing a NiN heterostructure with ReS2 / 1T'-MoTe2 / WS2 vertically stacked. S5. Electrode patterning and evaporation: Photoresist is coated on the surface of the prepared heterojunction sample. The patterns of the source electrode and the drain electrode are defined by exposure and development technology. A metal layer is deposited in the pattern using a metal evaporation process to form the source electrode, which is electrically in contact with the bottom contact layer, and the drain electrode, which is electrically in contact with the top absorption and collection layer, respectively. S6. Annealing and stabilization treatment: The device with the prepared electrodes is placed in a protective atmosphere for rapid annealing treatment.

2. The method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector according to claim 1, characterized in that: In step S1, the substrate is a P-type silicon wafer with a silicon dioxide dielectric layer on its surface; the ultrasonic cleaning is carried out sequentially using acetone solution, isopropanol solution and deionized water, and after cleaning and drying in step S1, a heating dehydration treatment is performed.

3. The method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector according to claim 1, characterized in that: In steps S2, S3, and S4, the transfer is performed using a dry transfer technique assisted by a polydimethylsiloxane carrier to complete the positioning and stacking.

4. The method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector according to claim 1, characterized in that: In step S2, the rhenium disulfide material is a 2H phase n-type semiconductor; in step S3, the metallic molybdenum ditelluride material is a 1T' phase intrinsic semiconductor; in step S4, the tungsten disulfide material is a 2H phase n-type semiconductor.

5. The method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector according to claim 1, characterized in that: In step S3, after the molybdenum ditelluride material is transferred and stacked, it is then subjected to in-situ phase stabilization treatment under an inert gas protective environment. The in-situ phase stabilization treatment employs a low-energy argon plasma irradiation process, and step S4 is executed immediately after the treatment is completed.

6. The method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector according to claim 1, characterized in that: In steps S2, S3, and S4, after each two-dimensional film is mechanically peeled off and before it is transferred and stacked to the target position, in-situ passivation modification is performed on the upper surface of the ReS2 film, the upper and lower surfaces of the 1T'-MoTe2 film, and the lower surface of the WS2 film under an inert gas protection environment. The in-situ passivation modification is performed using a chalcogenide saturated gas phase passivation process. After the passivation is completed, the corresponding film stacking and transfer operation is performed immediately.

7. The method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector according to claim 1, characterized in that: In step S5, the photoresist is polymethyl methacrylate photoresist; the deposited metal layer is a chromium-gold stacked structure or a titanium-gold stacked structure.

8. The method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector according to claim 1, characterized in that: In step S5, after the metal vapor deposition process is completed, the sample is immersed in acetone stripping solution and gently flushed with fluid to remove residual photoresist and metal layers in non-patterned areas. After stripping, the sample is rinsed with isopropanol and deionized water in sequence and then dried with inert gas.

9. The method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector according to claim 1, characterized in that: In step S6, the rapid annealing process is carried out in a protective atmosphere of nitrogen or argon, and the furnace is naturally cooled after annealing.

10. The method for fabricating a NiN-type two-dimensional heterojunction infrared photodetector according to claim 1, characterized in that: In steps S2 to S4, the ReS2 film, 1T'-MoTe2 film, and WS2 film are stacked in a strict bottom-up order; after each film is transferred, it is subjected to pressure holding and static treatment in the inert gas protection environment.

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