Grid-control asymmetric bow-tie antenna graphene terahertz detector and preparation method thereof

Abstract

The invention discloses a grid-control asymmetric bow-tie antenna graphene terahertz detector and a preparation method thereof. The grid-control asymmetric bow-tie antenna graphene terahertz detector comprises a graphene layer, an asymmetric bow-tie antenna, an insulating dielectric layer, a grid metal electrode layer and a substrate layer, the asymmetric bow-tie antenna is electrically connected with the graphene layer and comprises a first bow-tie antenna and a second bow-tie antenna which partially cover the two ends of the graphene layer respectively, and the middle of the first bow-tie antenna or the second bow-tie antenna is provided with a plurality of hollow structures used for amplifying the thermal photoelectric effect; an insulating medium layer is arranged on one side, far away from the asymmetric bow-tie antenna, of the graphene layer; the gate metal electrode layer is arranged on one side, far away from the graphene layer, of the insulating dielectric layer; the substrate layer is arranged on the side, away from the insulating dielectric layer, of the gate metal electrode layer. The graphene terahertz wave detector provided by the invention can realize high-response detection and polarization detection at room temperature.

Description

Technical Field

[0001] The present application relates to the technical field of terahertz wave detection, and in particular to a grid-controlled asymmetric bowtie antenna graphene terahertz detector and a preparation method thereof. Background Art

[0002] Terahertz waves refer to electromagnetic waves with a frequency range of 0.1T to 10Thz. They have the characteristics of low photon energy, high penetration, high bandwidth, high resolution and rich molecular fingerprint spectrum, which makes terahertz technology have broad application prospects in communication, bio-imaging, medical diagnosis and security detection. The core functional devices of terahertz technology mainly include terahertz sources, terahertz modulators and terahertz detectors. Existing terahertz detectors mainly include thermal detectors, photonic detectors and electronic detectors. However, the existing terahertz detectors are limited by their structural composition and cannot achieve high response and polarization-dependent terahertz wave detection under normal temperature conditions.

[0003] How to design a terahertz wave detector that works at room temperature so that it has both a high response size and can detect the polarization characteristics of terahertz waves has become a key technical problem that needs to be overcome urgently in this field. Summary of the invention

[0004] The present application provides a grid-controlled asymmetric bowtie antenna graphene terahertz detector and a preparation method to solve the technical problem of how to design a terahertz wave detector that works at room temperature so that it has both a high response size and can detect the polarization characteristics of terahertz waves, reduce the requirements of the terahertz wave detector on the environment, improve the response size of the terahertz wave detector at room temperature, and realize the polarization detection of terahertz signals.

[0005] In a first aspect, the present application provides a gate-controlled asymmetric bowtie antenna graphene terahertz detector, comprising: a graphene layer, an asymmetric bowtie antenna, an insulating dielectric layer, a gate metal electrode layer and a substrate layer; The asymmetric bowtie antenna is electrically connected to the graphene layer, and includes a first bowtie antenna and a second bowtie antenna. A plurality of hollow structures for amplifying the thermophotoelectric effect are provided in the middle of the first bowtie antenna or the second bowtie antenna. The first bowtie antenna partially covers one end of the graphene layer, and the second bowtie antenna partially covers the other end of the graphene layer. The insulating medium layer is provided on a side of the graphene layer away from the asymmetric bowtie antenna; The gate metal electrode layer is arranged on a side of the insulating dielectric layer away from the graphene layer; The substrate layer is arranged on a side of the gate metal electrode layer away from the insulating dielectric layer.

[0006] Preferably, the hollow structure is fan-shaped.

[0007] Preferably, the thickness of the asymmetric bowtie antenna ranges from 0.001 μm to 2 μm.

[0008] Preferably, the asymmetric bowtie antenna is a single material of any one of Al, Ag, Au, Bi, Cr, Ti, Ni and ion gel; or, the asymmetric bowtie antenna is a composite material composed of at least two of Al, Ag, Au, Bi, Cr, Ti, Ni and ion gel.

[0009] Preferably, an annular patch is provided in the bow tie groove of the asymmetric bow tie antenna.

[0010] Preferably, the asymmetric bowtie antenna further includes an asymmetric coplanar waveguide feeding structure connected to the bowtie slot.

[0011] Preferably, the graphene layer is a single layer or a multi-layer graphene layer.

[0012] Preferably, the insulating dielectric layer is a single material of any one of SiO2, Al2O3, HfO2, Si3N4, MgO, MnO2, h-BN, diamond, mica and polymer material films; or, the insulating dielectric layer is a composite material composed of at least two of SiO2, Al2O3, HfO2, Si3N4, MgO, MnO2, h-BN, diamond, mica and polymer material films.

[0013] In a second aspect, the present application further provides a method for preparing a gate-controlled asymmetric bowtie antenna graphene terahertz detector, which is used to prepare the gate-controlled asymmetric bowtie antenna graphene terahertz detector as described above, and the preparation method comprises: Performing sputtering, deposition or evaporation treatment on one surface of the obtained substrate layer to form a gate metal electrode layer; Performing oxidation and deposition treatment on the surface of the substrate on which the gate metal electrode layer is prepared to form an insulating dielectric layer; Transferring a graphene layer on a side of the insulating dielectric layer away from the substrate to obtain a graphene layer; Photolithography, sputtering, deposition or evaporation treatment is performed on two opposite ends of the graphene layer to form an asymmetric bowtie antenna, so as to obtain the gate-controlled asymmetric bowtie antenna graphene terahertz detector.

[0014] The present application provides a grid-controlled asymmetric bowtie antenna graphene terahertz detector and a preparation method. Compared with the prior art, the embodiments of the present application have the following beneficial effects: The graphene terahertz wave detector provided in the present application uses the graphene layer, the asymmetric bowtie antenna and the gate metal electrode layer as the effective detection parts, so as to effectively improve the response size of the graphene terahertz wave detector at room temperature and realize polarization detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the main structure of a grid-controlled asymmetric bowtie antenna graphene terahertz detector provided by a preferred embodiment of the present invention; Figure 2 It is a schematic diagram of a top view of a graphene terahertz detector with a grid-controlled asymmetric bowtie antenna provided by a preferred embodiment of the present invention; Figure 3 It is a schematic diagram of the light response size of the gate-controlled asymmetric bowtie antenna graphene terahertz detector provided by a preferred embodiment of the present invention under 2.52THz laser irradiation at different gate voltages; Figure 4 It is a schematic diagram of the ratio of the optical response to the maximum optical response of a grid-controlled asymmetric bowtie antenna graphene terahertz detector under 2.52THz laser irradiation at different polarization angles provided by a preferred embodiment of the present invention; Figure 5 It is a graphene Raman scattering spectrum diagram of a gate-controlled asymmetric bowtie antenna graphene terahertz detector provided by a preferred embodiment of the present invention; Figure 6 It is a schematic diagram of the steps of a method for preparing a grid-controlled asymmetric bowtie antenna graphene terahertz detector provided by a preferred embodiment of the present invention; 1-first bowtie antenna, 2-graphene layer, 3-second bowtie antenna, 4-insulating dielectric layer, 5-gate metal electrode layer, 6-substrate layer. DETAILED DESCRIPTION

[0016] The following is a detailed description of the implementation mode of the present application in conjunction with the accompanying drawings. The embodiments are provided only for illustrative purposes and cannot be understood as limiting the present application. The accompanying drawings are only for reference and illustration purposes and do not constitute a limitation on the scope of patent protection of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application. In the description of the present application, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0017] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used in this article are only for illustrative purposes, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. The term "and / or" used in this article includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0018] In the description of this application, it should be noted that, unless otherwise defined, all technical and scientific terms used in this application have the same meaning as those commonly understood by those skilled in the art. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood by specific circumstances.

[0019] The asymmetric bowtie antenna is a variation of the bowtie antenna. The shape of its upper and lower arms is similar to a bowtie, but the geometric structure or size of the two arms are not exactly the same, thus forming an asymmetry. The cross-sectional width of the two arms of the asymmetric bowtie antenna gradually widens from the middle to both sides, and the two arms overlap in the middle of the substrate. Therefore, the asymmetric bowtie antenna is actually an electric dipole, consisting of two equal but opposite charges. The two charges are separated by a certain distance at the center of the antenna to form an electric dipole with opposite polarity. The asymmetric bowtie antenna has a wide frequency band characteristic, the electric field is perpendicular to the antenna axis, and its intensity is the largest in two directions, making its radiation characteristics superior.

[0020] The graphene layer is a composite material structure composed of graphene and other materials, and has unique electrical, thermal, optical and other physical properties.

[0021] In view of this, in an embodiment of the present application, a gate-controlled asymmetric bowtie antenna graphene terahertz detector is provided, see Figure 1, including a graphene layer 2, an asymmetric bowtie antenna, an insulating dielectric layer 4, a gate metal electrode layer 5 and a substrate layer 6; the asymmetric bowtie antenna is electrically connected to the graphene layer 2, including a first bowtie antenna 1 and a second bowtie antenna 3, a plurality of hollow structures for amplifying the thermophotoelectric effect are provided in the middle of the first bowtie antenna 1 or the second bowtie antenna 3, the first bowtie antenna 1 partially covers one end of the graphene layer 2, and the second bowtie antenna 3 partially covers the other end of the graphene layer 2; an insulating dielectric layer 4 is provided on the side of the graphene layer 2 away from the asymmetric bowtie antenna; the gate metal electrode layer 5 is provided on the side of the insulating dielectric layer 4 away from the graphene layer 2; the substrate layer 6 is provided on the side of the gate metal electrode layer 5 away from the insulating dielectric layer 4.

[0022] Graphene has excellent electrical conductivity. When combined with other materials, the electrical conductivity of the heterojunction can be regulated, such as regulating the band gap size, enhancing the carrier transport performance, etc. The effective detection layer of the gate-controlled asymmetric bowtie antenna graphene terahertz detector provided in the present application uses a combination of a graphene layer 2, an asymmetric bowtie antenna and a gate metal electrode layer 5 to detect terahertz waves.

[0023] During the terahertz wave detection process, the terahertz wave is irradiated on the first bowtie antenna 1 and the second bowtie antenna 3, generating a photohot spot effect, and obtaining a current signal or a voltage signal on the asymmetric bowtie antenna. The voltage signal or the current signal excites hot carriers in the graphene layer 2 through the band, and the graphene hot carriers are cooled by the acoustic phonons of the graphene. After the graphene electrons absorb the terahertz wave, a temperature gradient is quickly formed, and the temperature difference with the metal lattice is maintained during the electron-phonon relaxation time. Under the action of the non-equilibrium electron temperature gradient, the graphene electrons produce a directional flow to form a measurable photocurrent. The asymmetric bowtie antenna includes the first bowtie antenna 1 and the second bowtie antenna 3. The middle part of the first bowtie antenna 1 or the second bowtie antenna 3 is provided with a plurality of hollow structures for amplifying the thermophotoelectric effect of the asymmetric bowtie antenna. The first bowtie antenna 1 partially covers one end of the graphene layer 2, and the second bowtie antenna 3 partially covers the other end of the graphene layer 2, and is electrically connected to the graphene layer 2. Due to the asymmetry of the asymmetric bow tie antenna, the temperatures at both ends are different. The different temperature gradients generate a photovoltage difference under the influence of the photothermoelectric effect, and a current signal or a voltage signal is obtained. Applying a voltage on the gate metal electrode layer 5 can change the size and polarity of the voltage signal or the current signal, such as Figure 3 The figure shows the optical response size of the gate-controlled asymmetric bowtie antenna graphene terahertz detector under 2.52THz laser irradiation at different gate voltages. The maximum optical response signal can be generated when the terahertz signal is polarized parallel to the asymmetric bowtie antenna, such as Figure 4Schematic diagram of the ratio of the optical response to the maximum optical response of a grid-controlled asymmetric bowtie antenna graphene terahertz detector under 2.52THz laser irradiation at different polarization angles provided by a preferred embodiment of the present invention. Figure 5 This is the graphene Raman scattering spectrum of the graphene terahertz detector with a gate-controlled asymmetric bowtie antenna.

[0024] The photothermoelectric effect is a representative photoelectric response mechanism in the gate-controlled asymmetric bowtie antenna graphene terahertz detector provided by the present application. Since the energy of the terahertz wave is at the meV level, which is much smaller than the energy of inter-band excitation, the voltage signal or current signal generated by the asymmetric bowtie antenna excites hot carriers in the graphene layer 2 through the band. At the same time, the small Fermi surface and the law of conservation of momentum limit the scattering of acoustic phonons on electrons, that is, the scattering effect of electrons and phonons in the graphene layer 2 is weak, while the scattering effect of electrons and electrons is relatively strong, and the interaction between graphene electrons and electrons is also shorter than the interaction between electrons and phonons. Since the electronic heat capacity of graphene is much smaller than the lattice heat capacity, the electrons quickly form a temperature gradient after absorbing the terahertz wave, and maintain the temperature difference with the lattice during the electron-phonon relaxation time. Under the action of this temperature difference, the electrons produce a directional flow to form a measurable photocurrent, so that the theoretical limit response speed of the gate-controlled asymmetric bowtie antenna graphene terahertz detector of the present application reaches the PS level.

[0025] In the preferred embodiment of the present application, the thickness of the graphene layer 2 ranges from 1 μm to 500 μm, and a single-layer graphene layer or a multi-layer graphene layer can be selected. The single-layer graphene layer has an extremely high electron mobility, which further improves the response size of the gate-controlled asymmetric bowtie antenna graphene terahertz detector provided by the present application. According to actual needs, the parameters of the graphene layer 2, such as the number of layers of the graphene layer 2 and the doping polarity and concentration, are adjusted to optimize the performance of the terahertz wave detector in a targeted manner, so as to improve the response size of the terahertz wave detection, and improve the sensitivity and stability of the gate-controlled asymmetric bowtie antenna graphene terahertz detector.

[0026] In the preferred embodiment of the present application, the graphene layer 2 may also adopt a graphene-molybdenum disulfide heterostructure, which is a vertical van der Waals heterostructure composed of graphene and molybdenum disulfide in transition metal disulfide compounds. Graphene and molybdenum disulfide are both two-dimensional layered materials. When they are combined in the form of a heterostructure, new interfaces and energy band structures can be formed, thereby exhibiting unique electrical and optical properties. For example, under light excitation, the charge transfer between graphene and molybdenum disulfide is achieved to improve the photoelectric response and energy conversion efficiency. The addition of molybdenum disulfide can further improve the response size of the gate-controlled asymmetric bowtie antenna graphene terahertz detector.

[0027] In a preferred embodiment of the present application, a terahertz wave signal is irradiated on an asymmetric bowtie antenna, and a current signal or a voltage signal can be obtained on the asymmetric bowtie antenna. A voltage is applied to the gate metal electrode layer to change the magnitude and polarity of the voltage signal or the current signal, thereby regulating the response magnitude of the gate-controlled asymmetric bowtie antenna graphene terahertz detector to the terahertz wave. The bowtie antenna itself has the characteristic of wide bandwidth, and the asymmetric design makes the hot carriers generated by the photothermoelectric effect of the two bowties different, further making different photovoltages or photocurrents generated at both ends of the asymmetric bowtie antenna, further improving the response magnitude of the gate-controlled asymmetric bowtie antenna graphene terahertz detector to terahertz wave detection.

[0028] In the preferred embodiment of the present application, Figure 2 As shown, one of the bow ties of the asymmetric bow tie antenna is a complete fan-shaped bow, and the other bow tie is also fan-shaped, but a number of hollow structures are opened in the middle for amplifying the thermophotoelectric effect. The fan-shaped antenna has a wide beam angle and can cover a larger area. The asymmetric design can further optimize the beam pattern of the antenna, giving it a stronger polarization measurement performance.

[0029] In a preferred embodiment of the present application, the number of hollow structures is greater than or equal to 1, and the number of hollow structures can be set according to needs and the shape of the hollow structures so that the gate-controlled asymmetric bowtie antenna graphene terahertz detector has a larger response size.

[0030] The asymmetric bowtie antenna fan-shaped design has a smaller size and weight, which is more convenient in installation and maintenance, especially in space-constrained environments where a compact structure is particularly important.

[0031] The selection of the thickness of the asymmetric bowtie antenna will cause changes in the response of the antenna at different frequencies, thereby affecting its bandwidth. The thickness selection of the asymmetric bowtie antenna should help maintain the stable performance of the antenna within the required frequency range. In a preferred embodiment of the present application, the thickness of the asymmetric bowtie antenna ranges from 0.001μm to 2μm. This thickness range enables the asymmetric bowtie antenna to have higher stability and larger response size in the terahertz band.

[0032] The material used for the asymmetric bowtie antenna also has an important influence on its performance. In the preferred embodiment of the present application, the asymmetric bowtie antenna is a single material of any one of Al, Ag, Au, Bi, Cr, Ti, Ni and ion gel, or a composite material composed of at least two of Al, Ag, Au, Bi, Cr, Ti, Ni and ion gel. Al, Ag, Au, Bi, Cr, Ti, Ni and ion gel all have good electrical conductivity and mechanical properties, which can further improve the stability of the grid-controlled asymmetric bowtie antenna graphene terahertz detector provided in the present application.

[0033] In a preferred embodiment of the present application, an annular patch is provided in the bowtie slot of the asymmetric bowtie antenna. The bowtie slot is located in the central area of ​​the asymmetric bowtie antenna and is shaped like an open bowtie or a bow tie. The annular patch can produce a specific radiation pattern, which is combined with the main radiator of the asymmetric bowtie antenna to optimize the radiation pattern and gain of the antenna. The annular patch can introduce additional resonant modes, thereby increasing the bandwidth of the antenna. The resonant mode introduced by the annular patch can be coupled with the main resonant mode of the asymmetric bowtie antenna to form a wider operating frequency band. The size and shape of the annular patch can be easily adjusted to achieve fine tuning of the antenna resonant frequency, so that the gate-controlled asymmetric bowtie antenna graphene terahertz detector provided by the present application can maintain stable performance over a wider frequency range.

[0034] In a preferred embodiment of the present application, the asymmetric bowtie antenna further includes an asymmetric coplanar waveguide feeding structure, which is connected to the bowtie slot. The asymmetric coplanar waveguide feeding structure can significantly improve the bandwidth of the asymmetric bowtie antenna by optimizing the feeding structure. This design not only improves the radiation efficiency of the asymmetric bowtie antenna, but also increases the frequency adaptability, so that the asymmetric bowtie antenna can communicate seamlessly in a wider frequency band, thereby further improving the response size and stability of the grid-controlled asymmetric bowtie antenna graphene terahertz detector disclosed in the present application.

[0035] In a preferred embodiment of the present application, an insulating dielectric layer 4 is provided on the side of the graphene layer 2 away from the asymmetric bowtie antenna; a gate metal electrode layer 5 is provided on the side of the insulating dielectric layer 4 away from the graphene layer 2; and a substrate layer 6 is provided on the side of the gate metal electrode layer 5 away from the insulating dielectric layer 4. The graphene Fermi level is regulated based on the voltage of the gate metal electrode layer 5, and the photothermoelectric effect of the gate-controlled asymmetric bowtie antenna graphene terahertz detector is regulated at the same time, changing the polarity and magnitude of the photocurrent or photovoltage of the gate-controlled asymmetric bowtie antenna graphene terahertz detector.

[0036] In a preferred embodiment of the present application, the material of the insulating dielectric layer 4 is any single material of SiO2, Al2O3, HfO2, Si3N4, MgO, MnO2, h-BN, diamond, mica and polymer material film, or a composite material composed of at least two of SiO2, Al2O3, HfO2, Si3N4, MgO, MnO2, h-BN, diamond, mica and polymer material film, and has good insulating properties.

[0037] In a preferred embodiment of the present application, the substrate layer 6 is a single material of any one of a polymer flexible film, an intrinsic semiconductor material and a doped semiconductor material containing other elements, or a composite material composed of at least two of the polymer flexible film, an intrinsic semiconductor material and a doped semiconductor material containing other elements, and the thickness of the substrate layer 6 is less than or equal to 1000 μm.

[0038] In a preferred embodiment of the present application, the insulating dielectric layer 4 can also be arranged on the side of the graphene layer 2 close to the asymmetric bowtie antenna, and the corresponding gate metal electrode layer 5 is arranged on the side of the insulating dielectric layer 4 away from the graphene layer 2, and the substrate layer 6 is arranged on the side of the gate metal electrode layer 5 away from the insulating dielectric layer 4. This structure can also regulate the graphene Fermi level based on the voltage of the gate metal electrode layer 5, and at the same time regulate the photothermoelectric effect of the gate-controlled asymmetric bowtie antenna graphene terahertz detector, and change the polarity and size of the photocurrent or photovoltage of the gate-controlled asymmetric bowtie antenna graphene terahertz detector.

[0039] Accordingly, in a preferred embodiment of the present application, based on the gate-controlled asymmetric bowtie antenna graphene terahertz detector of the present application, the present application embodiment also provides a method for preparing a gate-controlled asymmetric bowtie antenna graphene terahertz detector, which is used to prepare the gate-controlled asymmetric bowtie antenna graphene terahertz detector disclosed in the embodiment of the present application, such as Figure 6 As shown, the method includes: S1, performing sputtering, deposition or evaporation treatment on one surface of the obtained substrate layer to form a gate metal electrode layer; S2, performing oxidation and deposition treatment on the surface of the substrate on which the gate metal electrode layer is prepared to form an insulating dielectric layer; S3, transferring a graphene layer on a side of the insulating dielectric layer away from the substrate to obtain a graphene layer; S4. Performing photolithography, sputtering, deposition or evaporation processing on two opposite ends of the graphene layer to form an asymmetric bowtie antenna, so as to obtain the gate-controlled asymmetric bowtie antenna graphene terahertz detector.

[0040] The specific definition of the preparation method of a grid-controlled asymmetric bowtie antenna graphene terahertz detector can be found in the above-mentioned definition of a grid-controlled asymmetric bowtie antenna graphene terahertz detector, which will not be repeated here. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of this application.

[0041] A grid-controlled asymmetric bowtie antenna graphene terahertz detector and a preparation method provided in this embodiment are used to solve the technical problem of how to design a terahertz wave detector to achieve efficient detection of broadband terahertz waves under normal temperature conditions. It includes a graphene layer, an asymmetric bowtie antenna, an insulating dielectric layer, a gate metal electrode layer and a substrate layer; the asymmetric bowtie antenna is electrically connected to the graphene layer, including a first bowtie antenna and a second bowtie antenna, and a plurality of hollow structures for amplifying the thermophotoelectric effect are provided in the middle of the first bowtie antenna or the second bowtie antenna, the first bowtie antenna partially covers one end of the graphene layer, and the second bowtie antenna partially covers the other end of the graphene layer; an insulating dielectric layer is provided on the side of the graphene layer away from the asymmetric bowtie antenna; the gate metal electrode layer is provided on the side of the insulating dielectric layer away from the graphene layer; and the substrate layer is provided on the side of the gate metal electrode layer away from the insulating dielectric layer. The graphene terahertz wave detector provided in the present application uses the graphene layer, the asymmetric bowtie antenna and the gate metal electrode layer as effective detection parts, so as to effectively improve the response size of the graphene terahertz wave detector and realize polarization detection at room temperature.

[0042] Each embodiment in this specification is described in a progressive manner, and the same or similar parts of each embodiment can be directly referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the method embodiment, since it is basically similar to the system embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the system embodiment. It should be noted that the technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above-mentioned embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0043] The above-described embodiments only express several preferred implementations of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several improvements and substitutions can be made without departing from the technical principles of the present application, and these improvements and substitutions should also be regarded as the protection scope of the present application. Therefore, the protection scope of the patent application shall be based on the protection scope of the claims.

Claims

1. A gate-controlled asymmetric bowtie antenna graphene terahertz detector, characterized in that: It includes a graphene layer, an asymmetric bowtie antenna, an insulating dielectric layer, a gate metal electrode layer and a substrate layer; The asymmetric bowtie antenna is electrically connected to the graphene layer, and includes a first bowtie antenna and a second bowtie antenna. A plurality of hollow structures for amplifying the thermophotoelectric effect are provided in the middle of the first bowtie antenna or the second bowtie antenna. The first bowtie antenna partially covers one end of the graphene layer, and the second bowtie antenna partially covers the other end of the graphene layer. The insulating medium layer is provided on a side of the graphene layer away from the asymmetric bowtie antenna; The gate metal electrode layer is arranged on a side of the insulating dielectric layer away from the graphene layer; The substrate layer is arranged on a side of the gate metal electrode layer away from the insulating dielectric layer.

2. The gate-controlled asymmetric bowtie antenna graphene terahertz detector according to claim 1, characterized in that: The hollow structure is fan-shaped.

3. The gate-controlled asymmetric bowtie antenna graphene terahertz detector according to claim 1, characterized in that: The number of the hollow structures is greater than or equal to 1.

4. The gate-controlled asymmetric bowtie antenna graphene terahertz detector according to claim 1, characterized in that: The thickness of the asymmetric bowtie antenna ranges from 0.001 μm to 2 μm.

5. The gate-controlled asymmetric bowtie antenna graphene terahertz detector according to claim 1, characterized in that: The asymmetric bowtie antenna is a single material of any one of Al, Ag, Au, Bi, Cr, Ti, Ni and ion gel; or, the asymmetric bowtie antenna is a composite material composed of at least two of Al, Ag, Au, Bi, Cr, Ti, Ni and ion gel.

6. The gate-controlled asymmetric bowtie antenna graphene terahertz detector according to claim 1, characterized in that: An annular patch is arranged in the bow tie groove of the asymmetric bow tie antenna.

7. The gate-controlled asymmetric bowtie antenna graphene terahertz detector according to claim 6, characterized in that: The asymmetric bowtie antenna also includes an asymmetric coplanar waveguide feeding structure connected to the bowtie slot.

8. The gate-controlled asymmetric bowtie antenna graphene terahertz detector according to claim 1, characterized in that: The graphene layer is a single layer or a multilayer graphene.

9. The gate-controlled asymmetric bowtie antenna graphene terahertz detector according to claim 1, characterized in that: The insulating dielectric layer is a single material of any one of SiO2, Al2O3, HfO2, Si3N4, MgO, MnO2, h-BN, diamond, mica and polymer material films; or, the insulating dielectric layer is a composite material composed of at least two of SiO2, Al2O3, HfO2, Si3N4, MgO, MnO2, h-BN, diamond, mica and polymer material films.

10. A method for preparing a gate-controlled asymmetric bowtie antenna graphene terahertz detector, used for preparing the gate-controlled asymmetric bowtie antenna graphene terahertz detector according to any one of claims 1 to 9, characterized in that: The preparation method comprises: Performing sputtering, deposition or evaporation treatment on one surface of the obtained substrate layer to form a gate metal electrode layer; Performing oxidation and deposition treatment on the surface of the substrate on which the gate metal electrode layer is prepared to form an insulating dielectric layer; Transferring a graphene layer on a side of the insulating dielectric layer away from the substrate to obtain a graphene layer; Photolithography, sputtering, deposition or evaporation treatment is performed on two opposite ends of the graphene layer to form an asymmetric bowtie antenna, so as to obtain the gate-controlled asymmetric bowtie antenna graphene terahertz detector.

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