A Mid-Infrared Detector Based on Microstructure Regulation of Tantalum Nickel Selenide and Its Application

Abstract

A tantalum nickel selenide mid-infrared detector based on microstructure regulation according to the present invention has a silica layer provided on an intrinsic high-resistance silicon substrate. A plasmonic microstructure and a grating structure are provided on the silica layer. The grating structure is arranged at a distance from the plasmonic microstructure. A tantalum nickel selenide nanosheet is covered on the plasmonic microstructure and the grating structure. A hexagonal boron nitride nanosheet protection layer is covered on the tantalum nickel selenide nanosheet. The present invention utilizes the energy band alignment of tantalum nickel selenide and gold, and realizes the synergistic effect of enhanced mid-infrared absorption and asymmetric temperature distribution in the microstructure region with the plasmonic microstructure and the grating microstructure in the microstructure, so as to achieve efficient mid-infrared self-driven detection, high response speed, high efficiency, and high-performance infrared detection.

Description

Technical Field

[0001] The present invention belongs to the technical field of mid-infrared detection, and particularly relates to a mid-infrared detector based on tantalum nickel selenide with microstructure regulation and its application. Background Art

[0002] The mid-infrared band covers multiple transmission windows of the atmosphere and has advantages such as long action distance, strong haze penetration ability, and good anti-interference performance. Therefore, it has extensive applications in civil and military fields such as biomedical imaging, environmental monitoring, industrial detection, and infrared guidance. However, due to the small photon energy in the mid-infrared band, there are many challenges in achieving high-precision and high-sensitivity detection and regulation of it. For example, in the aspect of mid-infrared detectors, traditional detectors based on semiconductor materials such as mercury cadmium telluride usually require cryogenic refrigeration, and face technical bottlenecks such as difficult preparation process, high cost, and large dark count, resulting in problems such as high noise, slow response speed, and inability to achieve high-resolution imaging in current mid-infrared detection. In the aspect of mid-infrared optical modulation devices, in recent years, the rise of two-dimensional materials has provided a new direction for mid-infrared detection. As a representative material among them, black phosphorus has a narrow bandgap, high carrier mobility, and strong light-matter interaction, making it show great application potential in infrared photodetectors. However, due to its air stability problem, it is limited to the laboratory research stage. A new type of ternary sulfur layered compound tantalum nickel selenide Ta2NiSe5 has its layers combined by weak van der Waals forces, and the intra-layer is composed of a periodic zigzag chain formed by two TaSe6 octahedral single chains and NiSe4 tetrahedral single chains. This unique chain structure generates strong planar anisotropy. Different from conventional transition metal dichalcogenides TMDCs, Ta2NiSe5 maintains a constant direct narrow bandgap regardless of its thickness change. This unique atomic and energy band structure endows Ta2NiSe5 with excellent light absorption efficiency and stability. There have been research reports on the broad-spectrum visible to mid-infrared response, polarization sensitivity, and material anisotropy of Ta2NiSe5.

[0003] The optoelectronic response of Ta2NiSe5 mainly depends on the separation and transport of photo-generated carriers. In the mid-infrared band, due to the low photon energy, photo-generated carriers cannot be generated, resulting in a decrease in the responsivity of the detector. A self-powered photodetector requires the material itself to have a high photo-generated carrier mobility and low dark current. Without an external electric field, it is difficult for Ta2NiSe5-based detectors to achieve efficient optoelectronic conversion and signal output, and self-powered photodetection cannot be realized.

[0004] It can be seen that although Ta2NiSe5 has excellent broad-spectrum detection functions, its optoelectronic response mechanism limits its detection ability for mid-infrared radiation, and self-powered photodetection cannot be realized, which will greatly reduce its prospects in various communication and imaging applications.

[0005] Therefore, how to solve the problems of mid-infrared detectors in Ta2NiSe5 and provide a high responsivity and self-driven detection ability are technical problems that those skilled in the art urgently need to solve. Summary of the Invention

[0006] The first object of the present invention is to provide a mid-infrared detector based on tantalum nickel selenide with microstructure regulation for the problems in the prior art.

[0007] To achieve the above object of the present invention, the following technical solutions are adopted:

[0008] A mid-infrared detector based on tantalum nickel selenide with microstructure regulation, characterized in that: a silicon dioxide layer is provided on an intrinsic high-resistance silicon substrate, and a plasmonic microstructure is provided on the silicon dioxide layer, and the whole is rectangular. The plasmonic microstructure includes two cross-shaped plasmonic microstructures, which are arranged in a cross-finger shape with a spacing therebetween, and each cross-shaped plasmonic microstructure is respectively connected to a first positive electrode and a first negative electrode; the cross-shaped plasmonic metal microstructure includes a plurality of cross-shaped resonance structure units, which are uniformly distributed on the cross-finger structure; a grating structure is also provided on the silicon dioxide layer, and the whole is rectangular. The grating structure is arranged with a spacing from the plasmonic microstructure. The grating structure includes two grating microstructures, which are arranged in a cross-finger shape with a spacing therebetween, and each grating microstructure is respectively connected to a second positive electrode and a second negative electrode; a tantalum nickel selenide nanosheet is covered on the plasmonic microstructure and the grating structure, and a hexagonal boron nitride nanosheet protective layer is covered on the tantalum nickel selenide nanosheet;

[0009] The plasmonic microstructure and the grating microstructure are composite metal structures. The upper layer metal is gold. Through the energy band alignment of tantalum nickel selenide in the tantalum nickel selenide nanosheet and gold, and by synergistically enhancing the local resonance enhancement effect generated by the plasmonic microstructure and enhancing the incident light coupling of the grating microstructure, the mid-infrared absorption of the detector is enhanced, the mid-infrared response is enhanced at room temperature, and mid-infrared self-driven detection is achieved at room temperature.

[0010] While adopting the above technical solutions, the present invention can also adopt or combine the following technical solutions:

[0011] As a preferred technical solution of the present invention: the lower layer metal of the plasmonic microstructure is chromium with a thickness of 10 nm, the upper layer metal is gold with a thickness of 5 nm, and the overall size is 30 μm × 30 μm;

[0012] The cross-shaped plasmonic microstructure includes 6 cross-shaped plasmonic columns, which are arranged in a finger-like form, with a width of 0.2 μm and a spacing of 0.9 μm. The cross-shaped resonant structure units are evenly distributed on each cross-shaped plasmonic column. The dipole length of the plasmon of each cross-shaped resonant structure unit is 1.6 μm, the width is 0.1 μm, and the structural period of the cross-shaped resonant structure unit is 2.5 μm.

[0013] As a preferred technical solution of the present invention: the grating structure is a chromium-gold composite structure, the lower layer metal is chromium, serving as an adhesion layer with a thickness of 10 nm, and the upper layer metal is gold with a thickness of 50 nm. The overall size is 30 μm × 30 μm;

[0014] The grating microstructure includes 6 grating micro-columns, which are arranged in a finger-like form. Each grating micro-column is rectangular with a width of 0.2 μm, and the period of each grating micro-column is 2.5 μm.

[0015] As a preferred technical solution of the present invention: the resistivity of the intrinsic high-resistance silicon substrate is >10000 Ω·cm, and the thickness is 500 μm;

[0016] The thickness of the silicon dioxide layer is 300 nm;

[0017] The thickness of the tantalum nickel selenide nanosheet is 95 nm;

[0018] The thickness of the hexagonal boron nitride nanosheet is 15 nm.

[0019] As a preferred technical solution of the present invention: the first positive electrode, the first negative electrode, the second positive electrode, and the second negative electrode are made of chromium-gold composite electrodes. The lower layer metal is chromium, serving as an adhesion layer with a thickness of 10 nm, and the upper layer metal is gold with a thickness of 50 nm. The overall size of the four contact electrodes is 100 μm × 100 μm.

[0020] The second object of the present invention is to provide an application of a tantalum nickel selenide mid-infrared detector based on microstructure regulation for the problems in the prior art.

[0021] To this end, the above object of the present invention is achieved by the following technical solutions:

[0022] It is applied to a signal receiver for target data stream transmission, converting optical signals into electrical signals. The signals are collected and read by a preamplifier, a lock-in amplifier, and an oscilloscope, and finally the photocurrent is collected by decoding on a computer, and key performance parameters such as the responsivity, response speed, and self-driven detection are evaluated.

[0023] Compared with the prior art, a tantalum nickel selenide mid-infrared detector based on microstructure regulation and its application of the present invention have the following beneficial effects: Under mid-infrared excitation, by utilizing the energy band alignment of tantalum nickel selenide and gold, and the synergistic effect of the mid-infrared absorption enhancement and asymmetric temperature distribution in the microstructure region realized by the plasmonic microstructure and grating structure in the microstructure, the performance of the detector is significantly improved; The metasurface of the plasmonic microstructure introduces a new photoelectric detection mechanism based on hot carrier injection, realizing ultra-high-speed detection of low-energy photons and greatly enhancing the response speed; By utilizing the interfacial charge transfer transition path in the strongly coupled gold / tantalum nickel selenide heterostructure, hot electrons are directly excited by electrons, and through the mutual coupling of the photoelectric and photothermal physical processes, efficient mid-infrared self-driven detection, high response speed, high efficiency, and high-performance infrared detection are realized at room temperature, which has great application prospects in the field of photodetection technology. Description of the Drawings

[0024] Figure 1 is the front view of the structure of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention;

[0025] Figure 2 is the top view of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention;

[0026] Figure 3 In figure (a) is the schematic diagram of the size parameters of the cross-shaped resonance structure unit of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention; Figure 3 In figure (b) is the schematic diagram of the local size parameters of the grating structure of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention;

[0027] Figure 4 is the simulation result and experimental result of the absorption rate of the plasmonic microstructure of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention at a wavelength of 3-6 μm;

[0028] Figure 5 is the simulated electric field intensity amplification factor and temperature distribution of the plasmonic microstructure unit of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention under 4.6 um mid-infrared radiation;

[0029] Figure 6 In figure (a) is the optical micrograph of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention, Figure 6 In figure (b) is the 4.6 um mid-infrared photocurrent scanning image of the plasmonic microstructure and grating structure regions of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention under a 0.1 V bias voltage;

[0030] Figure 7The photocurrent magnitudes of the plasmonic microstructure and grating structure of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention at 0.1 V bias voltage at 520 nm, 638 nm, 940 nm, 1064 nm, 1310 nm, 1550 nm, and 4.6 μm;

[0031] Figure 8 In FIG. (a) therein is the 4.6 μm mid-infrared response time of the plasmonic microstructure of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention at 0.1 V bias voltage;

[0032] Figure 8 In FIG. (b) therein is the 4.6 μm mid-infrared response time of the grating structure of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention at 0.1 V bias voltage;

[0033] Figure 9 The 4.6 μm mid-infrared responsivity of the plasmonic microstructure and grating structure of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention at 0.1 V bias voltage varying with the incident power;

[0034] Figure 10 In FIG. (a) therein is the 4.6 μm mid-infrared photocurrent scanning image of the plasmonic microstructure and grating structure of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention at 0 V bias voltage; Figure 10 In FIG. (b) therein is the photocurrent distribution at the mid-line of the 4.6 μm mid-infrared photocurrent of the plasmonic microstructure and grating structure of a tantalum nickel selenide mid-infrared detector based on microstructure regulation of the present invention at 0 V bias voltage;

[0035] In the attached drawings, there are an intrinsic high-resistance silicon substrate 1, a silicon dioxide layer 2, a first positive electrode 3, a first negative electrode 4, a second positive electrode 5, a second negative electrode 6, a plasmonic microstructure 7, a grating structure 8, a tantalum nickel selenide nanosheet 9, and a hexagonal boron nitride nanosheet 10. Detailed implementation manners

[0036] The present invention will be further described in detail with reference to the attached drawings and specific embodiments.

[0037] The present invention relates to a tantalum nickel selenide mid-infrared detector based on microstructure regulation and its applications. The tantalum nickel selenide detector can enhance the mid-wave infrared optoelectronic performance of the device through microstructure. By combining the tantalum nickel selenide two-dimensional material with plasmons, high responsivity, high degrees of freedom, fast response, and self-driven detection capabilities are achieved. At the same time, the combination of the electromagnetic structure and the light-responsive material realizes the improvement of detection performance and the expansion of functions, providing an effective way to regulate the multifunctionality of two-dimensional optoelectronic materials.

[0038] A mid-infrared detector based on tantalum nickel selenide with microstructure regulation according to the present invention has a silicon dioxide layer 2 on an intrinsic high-resistance silicon substrate 1, four chromium-gold contact electrodes, a plasmonic microstructure 7 and a grating structure 8 on the silicon dioxide layer 2. Above the plasmonic microstructure 7 and the grating structure 8 is a tantalum nickel selenide nanosheet 9, and on it is a protective layer of hexagonal boron nitride nanosheet 10. The first positive electrode 3, the first negative electrode 4, the second positive electrode 5 and the second negative electrode 6 are externally connected to different circuits according to different functions for various optoelectronic tests.

[0039] The intrinsic high-resistance silicon substrate high-resistance silicon layer "1 is intrinsic high-resistance silicon with a resistivity of >10000 Ω·cm and a thickness of 500 μm; covered on it is a silicon dioxide layer 2 with a thickness of 300 nm;

[0040] The tantalum nickel selenide nanosheet 9 has a thickness of 95 nm; the hexagonal boron nitride nanosheet 10 has a thickness of 15 nm;

[0041] The four contact electrodes, the plasmonic microstructure and the grating microstructure are all composed of chromium and gold. The lower layer metal is chromium, serving as an adhesion layer with a thickness of 10 nm, and the upper layer metal is gold with a thickness of 50 nm. The overall size of the four contact electrodes is 100 μm×100 μm, and the overall size of the plasmonic microstructure region and the grating structure region is 30 μm×30 μm.

[0042] A mid-infrared detector based on tantalum nickel selenide with microstructure regulation according to the present invention is fabricated through the following technical solutions:

[0043] Step 1: First, use acetone, isopropanol, ethanol and deionized water to ultrasonically clean the surface of the silicon substrate covered with silicon dioxide, and cut the substrate into 1 cm×1 cm samples through precision cutting technology;

[0044] Step 2: Use a hot plate to bake and a spin coater to spin coat the photoresist AZ5350 to uniformly adhere to the above substrate;

[0045] Step 3: Combine ultraviolet lithography, electron beam evaporation method and traditional lift-off process to prepare the pre-designed contact electrodes;

[0046] Step 4: Use a hot plate to bake and a spin coater to spin coat the PMMA 950K-A4 to uniformly adhere to the substrate with the prepared contact electrodes;

[0047] Step 5: Combine electron beam lithography, electron beam evaporation method and traditional lift-off process to prepare the designed plasmonic microstructure and grating microstructure at the center of the contact electrodes;

[0048] Step 6: Using the micro-region positioning method of the transfer platform and the dry transfer technique, mechanically exfoliate the tantalum nickel selenide bulk material with blue tape, and then transfer it above the micro-structure for numbered positioning and marking;

[0049] Step 7: Using the micro-region positioning method of the transfer platform and the dry transfer technique, mechanically exfoliate hexagonal boron nitride with blue tape, and then transfer it onto the tantalum nickel selenide nanosheet for numbered positioning and marking;

[0050] Step 8: Attach the silicon substrate of tantalum nickel selenide with integrated micro-structure regulation to the PCB base, lead, and package to complete the directly testable detection device for enhancing mid-infrared response and achieving self-driven fast photodetection at room temperature.

[0051] Among them, in Steps 5, 6, and 7, Raman spectroscopy, optical microscopy, atomic force microscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy are used to characterize the morphology, size, and composition of the metal micro-structure, tantalum nickel selenide, and hexagonal boron nitride samples.

[0052] In the mid-infrared detector based on tantalum nickel selenide with micro-structure regulation of the present invention, based on the synergistic effect of the energy band alignment between tantalum nickel selenide and gold and the micro-structure, the transfer speed of hot electrons generated under mid-infrared excitation is fast enough, less than 100 fs, effectively avoiding the energy loss and the extension of the response time caused by the relaxation and recombination of carriers, and achieving an improved mid-infrared response speed at room temperature.

[0053] Compared with the prior art, the present invention has the following beneficial effects: A mid-infrared detector based on microstructure regulation and its application, which prepares an asymmetric microstructure on a substrate by means of electron beam lithography and electron beam evaporation. The asymmetric microstructure includes a plasmonic microstructure and a grating structure. The difference between the plasmonic microstructure and the grating structure lies in the presence or absence of dipoles that achieve plasmon resonance, realizing enhanced mid-infrared absorption and asymmetric temperature distribution in the microstructure region. Moreover, the plasmonic metasurface introduces a new photoelectric detection mechanism based on hot carrier injection, realizing ultra-high-speed detection of low-energy photons and greatly improving the response speed. At the same time, the tantalum nickel selenide two-dimensional material with room-temperature stability, easy cleavage and narrow bandgap grown by chemical vapor deposition is used as the channel photosensitive medium. Its bandgap can basically stably maintain a direct bandgap of 0.36 eV with the change of material thickness, and this material is a layered material stacked by weak van der Waals interactions. The inside of the layer is composed of a periodic sawtooth wave chain. Due to this unique atomic structure, while maintaining stability, regular long strips are prone to appear during mechanical peeling, which is beneficial to the integration and design of the device. The tantalum nickel selenide nanosheets are integrated at the microstructure by using the micro-region positioning method of the transfer platform and the dry transfer technology. Hexagonal boron nitride is used as a protective layer, which can further improve the stability of the device. The mid-infrared detector based on microstructure regulation of the present invention has a relatively simple structure and mature process. Under the regulation of the microstructure, the responsivity and response speed of tantalum nickel selenide are greatly improved, and self-driven detection of mid-wave infrared at room temperature is realized. The combination of the electromagnetic structure and the light-responsive material realizes the improvement of detection performance and the expansion of functions, providing an effective way to regulate the multifunctionality of two-dimensional optoelectronic materials, enhancing the mid-infrared response at room temperature, improving the mid-infrared response speed at room temperature, and realizing mid-infrared self-driven detection at room temperature.

[0054] In the present invention, based on the energy band alignment and synergistic effect of tantalum nickel selenide and metal cross-shaped plasmonic microstructures, through the mutual coupling of optoelectronic and photothermal physical processes, efficient mid-infrared self-driven detection is achieved. In the present invention, when mid-infrared light irradiates the plasmonic microstructure region, the microstructure induces local surface plasmon resonance, greatly enhancing the local electromagnetic field intensity and significantly improving the mid-infrared light absorption efficiency of tantalum nickel selenide in this region; under the enhanced light absorption effect, the density of photo-generated carriers in the tantalum nickel selenide nanosheets increases rapidly. At the same time, due to the energy band alignment and the thermal effect of the plasmonic microstructure, obvious photothermal conversion occurs in the tantalum nickel selenide material within the cross-shaped microstructure region. This photothermal conversion causes a significant increase in temperature in this region and forms a clear temperature gradient between the cross-shaped resonance structure unit region and other regions. The formation of the temperature gradient further drives the diffusion and drift processes of hot carriers: hot electrons migrate from the high-temperature region - the cross-shaped resonance structure unit region to the low-temperature region - the non-microstructure region along the temperature gradient direction, thus forming a stable thermal electric field within the tantalum nickel selenide nanosheet. This thermal electric field can drive photo-generated carriers to move in a specific direction without an external power supply and generate a detectable electrical signal between the electrodes, realizing mid-infrared self-driven optoelectronic detection.

[0055] In the present invention, the asymmetry of the microstructure is used to generate a temperature difference in the response material, thereby realizing the self-driven detection of the device in the mid-infrared. The transfer time of hot electrons excited by plasmons is on the order of femtoseconds, effectively improving the response speed. The advantages of the present invention include easy integration, high response rate, high degree of freedom, fast response, and self-driven detection ability. At the same time, the combination of the electromagnetic structure and the light-responsive material realizes the improvement of detection performance and the expansion of functions, providing an effective way to regulate the multifunctionality of two-dimensional optoelectronic materials.

[0056] In the present invention, the design of the staggered cross-shaped plasmonic microstructures provides a uniform distribution of the electric field, and the rectangular interdigitated structure provides more gaps between the cross-shaped resonance structure units: 1. By increasing the gaps between the cross-shaped resonance structure units, multiple parallel light-responsive units are formed, providing a larger light incident area, enhancing the interaction between light and plasmonic microstructures, and improving the light trapping efficiency. The tantalum nickel selenide material in the gap region is exposed to a higher-intensity local electromagnetic field, making the light absorption more sufficient; 2. The wider gap makes the drift path of photo-generated carriers shorter and reduces the charge recombination probability at the same time, thereby improving the optoelectronic conversion efficiency; 3. In the electrode gap, due to the more obvious local temperature gradient caused by the plasmonic microstructure, it promotes the rapid transfer of hot electrons and further improves the self-driven ability of the device; 4. The larger gap can effectively reduce the breakdown risk that may be caused by the over-concentration of the local electric field and improve the service life of the device.

[0057] In the present invention, the functions of the rectangular structure of the grating structure are as follows: 1) Enhance incident light coupling. Through the Bragg diffraction effect, the rectangular structure of the grating redistributes the path of the incident mid-infrared light, guiding more light energy to concentrate near the cross-shaped plasmonic structure. 2) Form light field modulation. The grating structure produces a diffraction enhancement effect at a specific wavelength, making the light field distribution more uniform and creating a better optical environment for the local surface plasmon resonance (LSPR) of the cross-shaped plasmonic microstructures.

[0058] Functions of the cross-shaped resonance structure unit:

[0059] 1) Local surface plasmon resonance (LSPR). Through precisely designed geometric dimensions: aspect ratio and period, the cross-shaped resonance structure unit can produce a significant enhancement of the local electromagnetic field in the mid-infrared band. 2) Carrier and hot electron management. Under the action of the enhanced local electric field, the cross-shaped resonance structure unit accelerates the generation and separation of photo-generated carriers, and at the same time improves the mid-infrared photothermal conversion efficiency through its thermal effect.

[0060] Synergistic effects of the two:

[0061] 1) The rectangular structure of the grating structure is distributed throughout the microstructure region. Through its guiding and collimating effects, the light energy is effectively concentrated in the local area where the cross-shaped structure is located, significantly enhancing the light trapping ability of the plasmon resonance. 2) The grating structure is mainly responsible for the coupling and modulation of the macroscopic light field, while the cross-shaped structure focuses on the enhancement of the local electromagnetic field and the improvement of the carrier efficiency. The combination of the two can improve the light absorption efficiency and charge separation efficiency in both directions.

[0062] In this application, the tantalum nickel selenide nanosheet only contacts the upper gold local area of the plasmonic microstructure and the grating structure, leaving non-contact areas. The energy band alignment between tantalum nickel selenide and gold mainly occurs at their directly contacting interfaces, resulting in interface energy band bending, and the interface effect plays a major role. 1. Tantalum nickel selenide is a two-dimensional layered material, and its optoelectronic properties are mainly concentrated on the surface; 2. The semi-contact structure of gold and tantalum nickel selenide mainly realizes its main functions through surface local effects: electromagnetic field enhancement, charge accumulation, heat diffusion, etc. For example, the enhancement effect of local surface plasmon resonance (LSPR) is limited to the nanoscale range near the surface, and the tantalum nickel selenide material in the non-contact area participates in the light absorption and carrier generation processes; 3. After the surface absorbs light energy, it will be converted into heat through the surface plasmon effect and diffuse to the non-contact tantalum nickel selenide area.

[0063] A mid-infrared detector based on micro-structure regulation and its application, disclosed by the present invention. The device preparation steps are as follows: First, four contact electrodes are fabricated using ultraviolet lithography technology and electron beam evaporation technology. Then, through electron beam lithography technology and electron beam evaporation technology, the designed metal micro-structure is filled at the channel to enhance the light absorption at specific wavelengths. After that, the tantalum nickel selenide nanosheet is dry-transferred above the micro-structure, and a boron nitride nanosheet is transferred as a protective layer to isolate the tantalum nickel selenide nanosheet from air. Finally, the preparation of the tantalum nickel selenide mid-infrared detector is completed through a bonding process. The tantalum nickel selenide mid-infrared detector of the present invention can achieve various functions such as enhanced mid-wave infrared light response and self-driven mid-infrared detection through different circuit designs. In addition, the present invention breaks through the bandgap limitation of traditional optoelectronic detection, thus showing obvious advantages in mid-infrared detection. The advantages of the present invention include high stability, self-driven detection, high responsivity, and fast response. At the same time, the degree of freedom provided by the device structure is conducive to integration and the construction of complex logic circuits, and is expected to be applied in aspects such as intelligent chips, image processing, and optical computing in the future.

[0064] The mid-infrared detector based on micro-structure regulation and its application of the present invention has the following beneficial effects:

[0065] 1. Asymmetric micro-structures, including plasmonic micro-structures and grating micro-structures, are prepared on the substrate by electron beam lithography and electron beam evaporation. The difference between the two lies in the presence or absence of dipoles for achieving plasmon resonance, which can enhance mid-infrared absorption in the micro-structure region and result in an asymmetric temperature distribution. And the plasmonic metasurface introduces a new optoelectronic detection mechanism based on hot carrier injection, achieving ultra-high-speed detection of low-energy photons and greatly improving the response speed.

[0066] 2. The two-dimensional material of tantalum nickel selenide, which is room-temperature stable, easy to cleave, and has a narrow bandgap, grown by chemical vapor deposition is used as the channel photosensitive medium. Its bandgap can basically stably maintain a direct bandgap of 0.36 eV with the change of material thickness, and this material is a layered material stacked by weak van der Waals interactions. The layer is composed of a periodic zigzag chain. Due to this unique atomic structure, while maintaining stability, it is easy to appear as relatively regular long strips during mechanical exfoliation, which is beneficial to the integration and design of the device. The tantalum nickel selenide nanosheet is integrated at the micro-structure using the micro-region positioning method of the transfer platform and dry transfer technology. Hexagonal boron nitride is used as a protective layer, which can further improve the stability of the device.

[0067] 3. The structure of this tantalum nickel selenide mid-infrared detector is relatively simple and the process is mature. Under the regulation of the microstructure, the responsivity and response speed of tantalum nickel selenide are greatly improved, and self-driven detection in the mid-wave infrared band at room temperature is achieved. The combination of the electromagnetic structure and the light-responsive material realizes the improvement of detection performance and the expansion of functions, providing an effective way to regulate the multifunctionality of two-dimensional optoelectronic materials.

[0068] As a sub-wavelength patterned surface with strong light interaction, the microstructure has become a promising candidate for the subsequent iteration of photodetectors. Carefully designed sub-wavelength nano-microstructures can achieve local field enhancement and optimal absorption at the desired wavelength, resulting in a significant increase in responsivity. It is worth noting that the plasmonic metasurface introduces a new type of photodetection mechanism based on hot carrier injection, enabling ultra-high-speed detection of low-energy photons. So far, plasmon-enhanced multilayer MoS2 and InSe have been successfully demonstrated in the visible light range. However, for some new two-dimensional materials such as Ta2NiSe5, the high responsivity of plasmon enhancement in the mid-infrared band is still under exploration. Based on the research background above, in this invention, a tantalum nickel selenide mid-infrared detector based on microstructure regulation encapsulated by hexagonal boron nitride nanosheets is innovatively proposed, and further research is carried out on its preparation method and multifunctional optoelectronic properties.

[0069] An application of a tantalum nickel selenide mid-infrared detector based on microstructure regulation for high-performance multifunctional detection in the mid-wave infrared. The laser is focused through the optical path, and an input control signal is used to make the mechanical shutter achieve data stream transmission. The tantalum nickel selenide mid-infrared detector based on microstructure regulation is used as a signal receiver to transmit the target data stream, convert the optical signal into an electrical signal, and the preamplifier, lock-in amplifier, and oscilloscope collect and read the signal. Finally, the photocurrent is collected by decoding on the computer side, and key performance parameters such as responsivity, response speed, and self-driven detection are evaluated. Example 1

[0070] The thickness of the silicon substrate covered with silicon dioxide is 500 μm; the thickness of the tantalum nickel selenide nanosheet is 95 nm, and the thickness of the hexagonal boron nitride nanosheet is 15 nm; the overall size of the four contact electrodes is 100 μm × 100 μm, and the overall sizes of the plasmonic microstructure region and the grating structure region are both 30 μm × 30 μm; the thicknesses of the above-mentioned microstructure and electrodes are both 60 nm, the thickness of chromium is 10 nm, and the thickness of gold is 50 nm; the first positive electrode 3, the first negative electrode 4, the second positive electrode 5, and the second negative electrode 6 are externally connected to different circuits according to different functions for various optoelectronic tests. The front view and top view of the tantalum nickel selenide mid-infrared detector are as shown in Figure 1 and Figure 2As shown, contact electrodes and microstructures are fabricated on a pre-prepared silicon substrate through processes such as electron beam lithography. After that, tantalum nickel selenide nanosheets are dry-transferred above the microstructures, and boron nitride nanosheets are transferred as a protective layer to isolate the tantalum nickel selenide nanosheets from air. Figure 3 Shows a schematic diagram of the size parameters of different microstructural units - plasmonic microstructures and grating structures in a tantalum nickel selenide mid-infrared detector. The length L2 of the dipole generating plasmons is 1.6 μm, the width W is 0.1 μm, the grating width L1 is 0.2 μm, and the structural periods of the two microstructures are P1 = P2 = 2.5 μm. The optical absorption rate of 3 - 6 μm for the plasmonic microstructures among them is simulated and tested. As Figure 4 shown, the good consistency between the experimental results and the simulation results demonstrates the reliability of the microstructure design. At the same time, the electric field intensity amplification factor and temperature distribution of the plasmonic microstructure unit at an incident wavelength of 4.6 μm are simulated. The results are as Figure 5 shown, indicating that the plasmonic microstructure can effectively amplify the electric field and increase the temperature, providing a theoretical basis for subsequent mid-infrared detection and proving the feasibility of the device design. Example 2

[0071] The thickness of the silicon substrate covered with silicon oxide is 500 μm; the thickness of the tantalum nickel selenide nanosheets is 95 nm, and the thickness of the hexagonal boron nitride nanosheets is 15 nm; the overall size of the four contact electrodes is 100 μm × 100 μm, and the overall sizes of the plasmonic microstructure region and the grating microstructure region are both 30 μm × 30 μm; the thicknesses of the above microstructures and electrodes are both 60 nm (10 nm of chromium / 50 nm of gold); the first positive electrode 3, the first negative electrode 4, the second positive electrode 5, and the second negative electrode 6 are externally connected to different circuits according to different functions for various optoelectronic tests. First, the morphology of the device structure is characterized by a microscope and an optoelectronic test system is used. By connecting the first positive electrode 3, the first negative electrode 4, the second positive electrode 5, and the second negative electrode 6 respectively, mid-infrared photocurrent scanning tests are carried out on the 4.6 μm of the plasmonic microstructure and grating microstructure regions under a 0.1 V bias voltage. The results are as Figure 6 shown. The difference in the colors of the two corresponds to the strength of the photocurrent. By comparison, it is found that the plasmonic microstructure is significantly enhanced compared to the grating microstructure, proving the enhanced effect of plasmons on mid-infrared response. In addition Figure 7It shows the photocurrent magnitudes of the plasmonic microstructure and grating microstructure of the tantalum nickel selenium mid-infrared detector at a bias voltage of 0.1 V at 520 nm, 638 nm, 940 nm, 1064 nm, 1310 nm, 1550 nm, and 4.6 μm. As the wavelength gradually approaches the target mid-infrared band, the enhancement effect of the photocurrent reaches its maximum, and the enhancement of the optical response can be more intuitively observed, indicating that the designed plasmonic microstructure can effectively improve the mid-infrared response of the tantalum nickel selenium two-dimensional material. Example 3

[0072] The thickness of the silicon substrate covered with silicon dioxide is 500 μm; the thickness of the tantalum nickel selenium nanosheet is 95 nm, and the thickness of the hexagonal boron nitride nanosheet is 15 nm; the overall size of the four contact electrodes is 100 μm × 100 μm, and the overall sizes of the plasmonic microstructure region and the grating microstructure region are both 30 μm × 30 μm; the thicknesses of the above microstructures and electrodes are all 60 nm (10 nm of chromium / 50 nm of gold); the first positive electrode 3, the first negative electrode 4, the second positive electrode 5, and the second negative electrode 6 are externally connected to different circuits according to different functions for various optoelectronic tests. The waveform diagram of the photocurrent of the tantalum nickel selenium mid-infrared detector was read through a lock-in amplifier and an oscilloscope, and the 4.6-μm mid-infrared response times of the plasmonic microstructure and the grating microstructure at a bias voltage of 0.1 V were extracted as Figure 7 shown in Figures (a) and (b) therein. The response time of the plasmonic microstructure was shortened by nearly an order of magnitude, demonstrating that the hot electrons generated by the plasmons can effectively improve the mid-infrared response speed. Subsequently, the responsivity of the tantalum nickel selenium mid-infrared detector was calculated, and the 4.6-μm mid-infrared responsivity of the plasmonic microstructure and the grating microstructure varying with the incident power at a bias voltage of 0.1 V as shown in Figure 9 was obtained. As the power changes, the mid-infrared responsivity of the plasmonic microstructure is always higher than that of the grating microstructure. As a core index of optoelectronic detection, the improvement of the responsivity fully indicates that the regulation of the plasmonic microstructure is an important means to improve the optoelectronic performance of the material itself. Example 4

[0073] The thickness of the silicon substrate covered with silicon dioxide is 500 μm; the thickness of the tantalum nickel selenium nanosheet is 95 nm, and the thickness of the hexagonal boron nitride nanosheet is 15 nm; the overall size of the four contact electrodes is 100 μm × 100 μm, and the overall sizes of the plasmonic microstructure region and the grating microstructure region are both 30 μm × 30 μm; the thicknesses of the above-mentioned microstructures and electrodes are both 60 nm (10 nm of chromium / 50 nm of gold); the first positive electrode 3, the first negative electrode 4, the second positive electrode 5, and the second negative electrode 6 are externally connected to different circuits according to different functions for various optoelectronic tests. The overall microstructure was characterized by a 4.6-μm photocurrent scan at a 0 V bias by connecting the first positive electrode 3 and the second negative electrode 6, and the results are as Figure 10 shown. It can be observed that there is an obvious asymmetric distribution of the photocurrent. To more intuitively compare its magnitude, the photocurrent distribution at the middle intercept line is also shown. The directions of the photocurrent on its left and right sides are opposite, and the magnitude of the photocurrent generated by the plasmonic microstructure is significantly larger than that of the grating structure. This not only realizes self-driven mid-infrared detection but also illustrates the enhancement effect of the plasmonic microstructure, proving that the asymmetric microstructure can effectively expand the mid-infrared detection performance.

[0074] The above specific implementation manners are used to explain the present invention. They are only the preferred embodiments of the present invention and do not limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and scope of the claims of the present invention fall within the protection scope of the present invention.

Claims

1. A mid-infrared detector based on tantalum nickel selenide with microstructure regulation, characterized in that: A silicon dioxide layer is provided on an intrinsic high-resistance silicon substrate, and a plasmonic microstructure is provided on the silicon dioxide layer. The overall shape is rectangular. The plasmonic microstructure includes two cross-shaped plasmonic microstructures, which are arranged in a cross-finger pattern with a spacing therebetween. Each cross-shaped plasmonic microstructure is respectively connected to a first positive electrode and a first negative electrode; the cross-shaped plasmonic metal microstructure includes a plurality of cross-shaped resonance structure units, which are uniformly distributed on the cross-finger structure; a grating structure is also provided on the silicon dioxide layer, and the overall shape is rectangular. The grating structure is arranged at a spacing from the plasmonic microstructure. The grating structure includes two grating microstructures, which are arranged in a cross-finger pattern with a spacing therebetween. Each grating microstructure is respectively connected to a second positive electrode and a second negative electrode; a tantalum nickel selenide nanosheet is covered on the plasmonic microstructure and the grating structure, and a hexagonal boron nitride nanosheet protective layer is covered on the tantalum nickel selenide nanosheet; The plasmonic microstructure and the grating structure are composite metal structures. The upper-layer metal is gold. Through the energy band alignment of tantalum nickel selenide in the tantalum nickel selenide nanosheet and gold, the local resonance enhancement effect generated by the plasmonic microstructure and the grating structure that enhances the incident light coupling are synergistically used to enhance the mid-infrared absorption of the detector, enhance the mid-infrared response at room temperature, and realize mid-infrared self-driven detection at room temperature; Among them, the grating structure redistributes the path of the incident mid-infrared light, guiding more light energy to concentrate near the cross-shaped plasmonic structure. The tantalum nickel selenide material generates obvious photothermal conversion in the cross-shaped microstructure region. This photothermal conversion causes a significant increase in temperature in this region, and a clear temperature gradient is formed between the cross-shaped resonance structure unit region and other regions. Hot electrons migrate from the high-temperature region - the cross-shaped resonance structure unit region to the low-temperature region - the non-microstructure region along the temperature gradient direction, thereby forming a stable thermal electric field in the tantalum nickel selenide nanosheet.

2. The mid-infrared detector based on tantalum nickel selenide with microstructure regulation according to claim 1, characterized in that: The lower-layer metal of the plasmonic microstructure is chromium, with a thickness of 10 nm, and the upper-layer metal is gold, with a thickness of 50 nm. The overall size is 30 μm×30 μm; The cross-shaped plasmonic microstructure includes 6 cross-shaped plasmonic columns, which are arranged in a finger-like form, with a width of 0.2 μm and a spacing of 0.9 μm. The cross-shaped resonance structure units are uniformly distributed on each cross-shaped plasmonic column. The length of the dipole of the plasmon of each cross-shaped resonance structure unit is 1.6 μm, and the width is 0.1 μm. The structural period of the cross-shaped resonance structure unit is 2.5 μm.

3. The mid-infrared detector based on microstructure regulation as described in claim 1, characterized in that: The grating structure is a chromium-gold composite structure. The lower-layer metal is chromium, serving as an adhesion layer, with a thickness of 10 nm, and the upper-layer metal is gold, with a thickness of 50 nm. The overall size is 30 μm×30 μm; The grating microstructure includes 6 grating micro-columns, which are arranged in a finger-like form. Each grating micro-column is rectangular, with a width of 0.2 μm, and the period of each grating micro-column is 2.5 μm.

4. The mid-infrared detector based on microstructure regulation according to claim 1, characterized in that: The resistivity of the intrinsic high-resistance silicon substrate is >10000 Ω·cm, and the thickness is 500 μm; The thickness of the silicon dioxide layer is 300 nm; The thickness of the tantalum nickel selenide nanosheet is 95 nm; The thickness of the hexagonal boron nitride nanosheet is 15 nm.

5. The mid-infrared detector based on microstructure regulation as described in claim 1, wherein: The first positive electrode, the first negative electrode, the second positive electrode and the second negative electrode are made of chromium-gold composite electrodes. The lower layer metal is chromium, serving as an adhesion layer with a thickness of 10 nm, and the upper layer metal is gold with a thickness of 50 nm. The overall size of the four contact electrodes is 100 μm × 100 μm.

6. Use of the mid-infrared detector based on microstructure regulation according to any one of claims 1-5, characterized in that: It is applied to a signal receiver for target data stream transmission, converting optical signals into electrical signals. The preamplifier, lock-in amplifier and oscilloscope are used to collect and read the signals, and finally the photocurrent is collected by decoding on the computer side. Moreover, the responsivity, response speed and self-driven detection performance parameters are evaluated.

Images