Topological semi-metallic terahertz detector integrated with butterfly antenna and its fabrication method

Abstract

This invention discloses a topological semi-metallic terahertz detector integrated with a butterfly antenna and its fabrication method. The device fabrication steps mainly involve mechanical lift-off, ultraviolet lithography, thermal evaporation coating, point transfer, and ultrasonic wire bonding to form the butterfly antenna-integrated topological semi-metallic terahertz detector. The device structure, from bottom to top, consists of: a first layer of intrinsic silicon substrate, a second layer of oxide layer, a third layer of topological semi-metallic nickel selenide telluride and butterfly antenna electrodes, and a fourth layer of topological semi-metallic graphene. By integrating the butterfly antenna and constructing a terahertz detector using a topological semi-metallic vertical heterojunction, the topological characteristics of the quantum states of the topological semi-metallic material can be tuned. The butterfly antenna can be used to focus the terahertz light field and improve the material's light absorption, ultimately achieving terahertz detection and imaging functions at room temperature. The advantages of this invention are fast detector response speed, self-driven operation at room temperature, low noise equivalent power, and ease of integration.

Description

Technical Field

[0001] This invention relates to a topological semimetal terahertz detector with integrated butterfly antenna, its fabrication method, performance testing, and room temperature imaging. Specifically, it utilizes the high carrier mobility, nontrivial topological properties, and lattice mismatch-free vertical stacking of two-dimensional materials, of the topological semimetals nickel selenide telluride and graphene. By integrating and optimizing the butterfly antenna, terahertz waves are efficiently focused, forming a potential gradient at both ends of different materials to drive the flow of non-equilibrium carriers. This greatly reduces the dark current and noise equivalent power of the device, thereby achieving a self-driven operating mode at room temperature and zero bias voltage and terahertz transmission imaging of metallic objects. Background Technology

[0002] Terahertz electromagnetic spectrum ranges from 0.1 to 10 THz, combining the advantages of both microwave electronics and infrared photonics. Research in terahertz technology involves disciplines such as physics, chemistry, materials science, and semiconductor science and technology, making it a typical interdisciplinary frontier technology field. This provides new technological avenues for atmospheric remote sensing, 6G communications, national defense security, and non-destructive testing. Due to the importance of terahertz technology, it has sparked a research boom worldwide. Undoubtedly, finding photodetectors with high sensitivity, fast response, and room temperature stability in the terahertz band is crucial for the development of terahertz technology. After decades of development, commercially available terahertz photodetectors (Gaolei tubes, Schottky diodes, calorimeters, etc.) still face some application challenges, such as complex device manufacturing processes, poor flexibility, and high prices. These factors limit the widespread application of terahertz technology.

[0003] In recent years, the rapid development of materials science and semiconductor manufacturing technology has prompted researchers to explore new material systems and fabrication methods to achieve highly sensitive and ultrafast terahertz photodetectors operating at room temperature. The unique structure and properties of two-dimensional materials have provided new opportunities for the development of novel photodetector technologies. Among them, topological half-metals possess low-energy electronic states in the terahertz band, enabling terahertz light detection using exotic quantum phenomena. Furthermore, their zero-bandgap structure allows for a response wavelength range from the ultraviolet to the terahertz range. On one hand, the massless Dirac fermions associated with linearly dispersive electron bands in topological half-metals, along with efficient photothermoelectric effects and chiral terahertz field emission, give terahertz photodetectors low dissipation and ultrafast response, making them ideal candidate materials for terahertz photodetectors. In addition, another important factor is the crucial role of antennas in terahertz detectors. Antennas effectively couple terahertz radiation and buffer mismatches in free space, improving the performance of the terahertz detector while enhancing the directivity of the terahertz light field.

[0004] As is well known, since two-dimensional materials have fewer dangling bonds on their surfaces and are not limited by lattice matching, further integrating different topological half-metals to form van der Waals heterostructures with the combined properties of each component provides an effective way to explore new terahertz detectors. Summary of the Invention

[0005] This invention proposes a room-temperature-controlled, topologically semi-metallic heterojunction terahertz detector integrated with a butterfly antenna and its fabrication method. Under the favorable conditions of efficient terahertz light field focusing by the butterfly antenna, this heterojunction device utilizes a temperature gradient generated by the difference in Seebeck coefficients at both ends to drive unidirectional carrier motion, achieving high-speed, high-sensitivity terahertz detection and imaging capabilities in a self-driven operating mode at room temperature.

[0006] The detector's structure from bottom to top is as follows: the first layer is a high-resistivity silicon substrate 1; the second layer is an oxide layer silicon dioxide 2; the third layer is a topological half-metal selenium tellurium nickel 3 and a butterfly antenna electrode source terminal 4 and a drain terminal 5, wherein the butterfly antenna electrode source terminal 4 is in contact with the selenium tellurium nickel 3, and the butterfly antenna electrode drain terminal 5 is not in contact with the selenium tellurium nickel 3; the fourth layer is graphene 6, wherein the selenium tellurium nickel 3 and the graphene 6 are in contact.

[0007] The substrate 1 is an intrinsically high-resistivity silicon substrate;

[0008] Oxide layer 2 is silicon dioxide;

[0009] The described selenium tellurium nickel 3 is a selenium tellurium nickel nanosheet;

[0010] The butterfly antenna electrode source end 4 and butterfly antenna electrode drain end 5 are metal composite electrodes, with the lower metal being chromium and the upper metal being gold.

[0011] The graphene 6 described herein is multilayered.

[0012] This invention relates to a room-temperature-temperature (RTT) butterfly antenna integrated topological semi-metallic heterojunction terahertz detector and its fabrication method. The device fabrication includes the following steps: First, a topological semi-metallic single-crystal nickel selenide-telluride bulk material is mechanically exfoliated onto a high-resistivity silicon substrate using low-adhesion adhesive tape. Then, a butterfly antenna structure is fabricated using ultraviolet lithography, thermal evaporation coating, and traditional exfoliation processes, at which point the nickel selenide-telluride only contacts one end of the butterfly antenna electrode. Next, single-crystal graphene is mechanically exfoliated onto polydimethylsiloxane using low-adhesion adhesive tape, and multilayer graphene is transferred to the contact between the nickel selenide-telluride and the butterfly antenna electrode using a two-dimensional material transfer platform. Then, the device is attached to a base and encapsulated using ultrasonic wire bonding, finally forming a butterfly antenna integrated topological semi-metallic heterojunction terahertz detector.

[0013] The advantages of this invention patent are:

[0014] 1) The channel material chosen is a topological half-metal. This material has a Dirac band structure and chiral electronic state characteristics, which makes it suitable for use in terahertz detectors with broadband and high-speed optical responses.

[0015] 2) Nickel selenide telluride and graphene materials have advantages such as environmental stability, scalability and low cost of raw materials. High efficiency and low surface contamination heterojunction devices can be prepared through site transfer technology.

[0016] 3) By adopting an easily integrated butterfly antenna structure, electromagnetic waves in the subwavelength channel are super-focused, which can effectively enhance the interaction between terahertz waves and Dirac electron gas.

[0017] 4) Taking advantage of the absence of lattice mismatch in vertical stacking of two-dimensional materials, van der Waals heterojunctions are constructed. Due to the difference in Seebeck coefficients between the two materials, non-equilibrium electrons can flow in one direction, resulting in low power consumption and self-driven operation at room temperature.

[0018] 5) Topological semimetal selenium tellurium nickel and graphene heterojunction devices have the technical advantages of low dark current, low noise equivalent power and response time in the microsecond range, and have successfully realized the application of terahertz transmission imaging of metallic materials at room temperature. Attached Figure Description

[0019] Figure 1 This is a side view schematic diagram of the structural unit of the topological semi-metallic terahertz detector integrated with the butterfly antenna of the present invention.

[0020] Figure 2 This is a top view schematic diagram of the topological semi-metallic terahertz detector integrated with the butterfly antenna of the present invention.

[0021] Figure 3 This is a schematic diagram of the optical response of the topological semi-metallic terahertz detector integrated with the butterfly antenna of the present invention under different bias voltages and different terahertz bands of radiation.

[0022] Figure 4 This is a schematic diagram of the time-resolved optical response of the topological semi-metallic terahertz detector integrated with the butterfly antenna of the present invention under different bias voltages.

[0023] Figure 5 This is a schematic diagram of the noise current density of the topological semi-metallic terahertz detector integrated with the butterfly antenna of the present invention.

[0024] Figure 6 This is a graph showing the photocurrent changes of the topological semi-metallic terahertz detector integrated with the butterfly antenna of this invention after one month at room temperature. Detailed implementation method:

[0025] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings:

[0026] This invention relates to a method for fabricating, mechanism study, and performance improvement of a room-temperature butterfly antenna integrated topological semi-metallic heterojunction terahertz detector. Specifically, it refers to constructing a vertical van der Waals heterojunction using topological semi-metals selenium telluride nickel and graphene, and using an integrated and optimized butterfly antenna to efficiently focus terahertz waves to form a potential gradient at both ends of different materials to drive the flow of non-equilibrium carriers, which greatly reduces the dark current and noise equivalent power of the device, thereby achieving a self-driven operating mode at room temperature and terahertz transmission imaging applications on metallic objects.

[0027] The specific steps are as follows:

[0028] 1. Substrate selection

[0029] Intrinsic silicon 1 and silicon dioxide 2 covering it were selected as substrates.

[0030] 2. Preparation and transfer of nickel selenium telluride

[0031] High-quality nickel selenide-tellurium single crystals were prepared using a slow cooling method. High-purity nickel powder (99.99%), selenium powder (99.999%), and tellurium powder (99.9999%) were mixed in a 1:1:1 ratio and vacuum-sealed in a conical quartz tube. The quartz tube was heated and then slowly cooled to form nickel selenide-tellurium single crystals. Next, low-tack adhesive tape was used to mechanically exfoliate the nickel selenide-tellurium bulk material to obtain nickel selenide-tellurium flakes, which were then transferred onto a high-resistivity silicon substrate.

[0032] 3. Fabrication of butterfly antenna electrodes

[0033] The butterfly antenna structure electrode was fabricated using ultraviolet lithography, thermal evaporation coating, and traditional lift-off processes. Figure 2 The lower layer of the vapor-deposited metal is chromium, and the upper layer is gold; the selenium tellurium nickel sheet only contacts one end of the butterfly antenna electrode.

[0034] 4. Transfer of graphene

[0035] First, multilayer graphene was obtained by mechanically exfoliating the graphene bulk material using low-tack adhesive tape and transferred onto polydimethylsiloxane. Then, the target graphene on the nickel selenide-telluride substrate and the polydimethylsiloxane substrate was observed using a microscope on a two-dimensional material transfer platform. The side of the polydimethylsiloxane substrate without graphene was attached to a glass slide, and the graphene was transferred to the nickel selenide-telluride substrate and antenna electrode contacts via targeted transfer. During the transfer process, the substrate silicon wafer could be heated to facilitate the detachment of the multilayer graphene from the polydimethylsiloxane.

[0036] 5. Packaged devices

[0037] The device is attached to the base printed circuit board and encapsulated using ultrasonic wire bonding technology.

[0038] 6. Photoelectric response test

[0039] A microwave signal source is used to establish a frequency doubling link, enabling terahertz signal output. The modulation frequency of the microwave source's pulse signal serves as the reference signal for the lock-in amplifier and oscilloscope. Simultaneously, the detector's photoelectric signal, amplified by a preamplifier, is connected to the input port of the lock-in amplifier. The output signal is the signal further amplified by the lock-in amplifier. This system improves the signal-to-noise ratio and enables automated testing of the terahertz detector's response signal and response time. Figure 3 The photocurrent-dependent bias voltage response characteristics of the heterojunction device were shown, and the photodetector exhibited a high responsivity. The results demonstrate that the topological semi-metallic heterojunction detector provided by this invention has good detection capability under zero bias voltage, and that the method for improving the device's detection capability through butterfly antenna integration is feasible. Figure 4 Time-resolved optical response diagrams of the topological semi-metallic heterojunction terahertz detector integrated for a butterfly antenna under different bias voltages are shown. The pulse shape is well preserved, and it exhibits a low signal-to-noise ratio. These results demonstrate that the method for effectively reducing dark current using the topological semi-metallic heterostructure provided in this invention is feasible. Figure 5 Noise current density plot of a topological semi-metallic heterojunction terahertz detector integrated with a room-temperature butterfly antenna.

[0040] 7. Environmental stability test

[0041] Figure 6 The photocurrent changes of a topological semi-metallic heterojunction terahertz detector integrated with a butterfly antenna after one month at room temperature are shown. The natural oxidation process on the surface of nickel selenide-telluride forms a capping layer, protecting the activity of nickel selenide-telluride in the environment. The results demonstrate that the topological semi-metallic heterojunction detector provided by this invention possesses stability and reproducibility.

[0042] The topological semi-metallic heterojunction terahertz detector integrated with a butterfly antenna in this invention can significantly improve the overall optical response of the device, such as reducing dark current noise, achieving a response time in the microsecond range, high responsivity, and low power consumption with self-powered operation. The results indicate that the room-temperature butterfly antenna integrated with a topological semi-metallic heterojunction terahertz detector of this invention may be a promising and ideal approach for realizing quantum material technology applications in the terahertz range.

Claims

1. A topological semi-metallic terahertz detector integrated with a butterfly antenna, comprising an intrinsic silicon substrate (1), an oxide layer (2), nickel selenide telluride (3), a butterfly antenna electrode source terminal (4), a butterfly antenna electrode drain terminal (5), and graphene (6), characterized in that: The structure of the terahertz detector from bottom to top is as follows: the first layer is an intrinsic silicon substrate (1), the second layer is an oxide layer (2), the third layer is a topological half-metal nickel selenide (3), and the source end of the butterfly antenna electrode that contacts the nickel selenide (4) and the drain end of the butterfly antenna electrode that does not contact the nickel selenide (5), and the fourth layer is graphene (6). The substrate (1) is an intrinsically high-resistivity silicon substrate; The oxide layer (2) is silicon dioxide; The aforementioned topological half-metal selenium tellurium nickel (3) is a selenium tellurium nickel nanosheet; The source end (4) and drain end (5) of the butterfly antenna electrode are metal composite electrodes, with chromium as the lower metal and gold as the upper metal. The graphene (6) is multilayered.

2. A method for fabricating a topological semi-metallic terahertz detector integrated with a butterfly antenna as described in claim 1, characterized in that... The steps are as follows: First, a topological semimetal single-crystal nickel selenide-telluride bulk material is mechanically exfoliated onto a high-resistivity silicon substrate using low-tack tape. Then, a butterfly antenna structure is fabricated using ultraviolet lithography, thermal evaporation coating, and a traditional exfoliation process, with the nickel selenide-telluride only contacting one end of the butterfly antenna electrode. Next, single-crystal graphene is mechanically exfoliated onto polydimethylsiloxane using low-tack tape, and then multilayer graphene is transferred to the contact point between the nickel selenide-telluride and the butterfly antenna electrode using a two-dimensional material transfer platform. Finally, the device is attached to a base and encapsulated using ultrasonic wire bonding, ultimately forming a butterfly antenna-integrated topological semimetal heterojunction terahertz detector.

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