Vertical heterojunction rectification antenna based on topological insulator zirconium telluride-graphene and preparation method thereof

Abstract

The invention relates to a vertical heterojunction rectification antenna based on topological insulator zirconium telluride-graphene and a preparation method thereof. The rectifying antenna is structurally characterized in that a silicon dioxide oxide layer is arranged on a silicon substrate, a gold bottom electrode is firstly subjected to electron beam photoetching on the silicon dioxide oxide layer, zirconium telluride and graphene are sequentially transferred on the bottom electrode through a method, a top electrode is subjected to electron beam photoetching on the tops of the zirconium telluride and the graphene, the rectifying antenna is structurally composed of asymmetric vertical antennas, and the distance between a source and a drain is 50-90 nm; and the zirconium telluride and the graphene are positioned in an electrode channel formed by the bottom electrode and the top electrode. Based on unique electrical characteristics of a topological insulator zirconium telluride, high-sensitivity and high-efficiency terahertz wave detection and high-bandwidth and fast-response frequency mixing rear-end application are realized by utilizing strong nonlinear response of Dirac semimetal and a topological insulator material in a terahertz frequency range.

Description

Technical Field

[0001] The present invention relates to the technical field of rectennas, and in particular to a vertical heterojunction rectenna based on topological insulator zirconium telluride-graphene and a preparation method thereof. Background Art

[0002] Terahertz radiation (0.1-10THz) is a bridge between electronic devices and optical devices, covering a wide band of electromagnetic spectrum from microwaves to infrared light. Its unique hybrid characteristics make it have broad application potential in wireless communications, sensing and imaging. In recent years, with the rapid development of emerging two-dimensional materials such as graphene, transition metal chalcogenides (TMDCs), topological materials and three-dimensional Dirac systems, the research on the unique electrical and optical properties of these materials has greatly promoted the technological progress of terahertz optoelectronic devices.

[0003] Among these materials, topological materials exhibit unique broadband response characteristics due to their massless Dirac fermions. With their unique topological surface states and dissipative electron transport characteristics, topological materials have shown important application value in the design of high-performance, broadband, room-temperature-operated optoelectronic devices. According to the topological properties of the electronic band structure in momentum space, topological materials can be divided into topological insulators (TI), Dirac semimetals (DS), Weyl semimetals (WS) and node-linesemimetals (NLS). Among them, topological insulators exhibit ultra-high carrier mobility due to the low energy loss of surface state carriers during transmission, which gives them potential advantages in high-speed, low-energy electronic and optoelectronic devices.

[0004] Although the above advantages make two-dimensional materials have potential in optoelectronic applications in the terahertz band, their development still faces many challenges. This is mainly due to their weak optical absorption, high dark current and inefficient charge separation mechanism, which limit their light detection capabilities in the low photon energy range of the terahertz band. In addition, although traditional thermal and photon photodetectors can be used for low-energy photon detection, they are restricted by problems such as low response speed, low-temperature cooling and high power consumption. Therefore, the development of high-performance terahertz photodetectors with excellent performance at room temperature remains a challenging task. How to effectively overcome the high dark current problem of traditional room-temperature terahertz detectors so that the photocurrent is not submerged in the noise current and a clear electrical signal can be extracted is a major problem in current research. In addition, the limitation of the electron transit time of the detector on the response bandwidth and speed is a key factor in determining the performance of terahertz detectors. Therefore, how to fundamentally optimize the device structure and material properties to improve the response rate and sensitivity of the detector is a technical problem that needs to be solved by technicians in this field.

[0005] For decades, zirconium telluride has attracted extensive research attention due to its excellent thermoelectric properties, resistivity anomaly and its performance in quantum oscillations. The band structure of zirconium telluride is at the phase boundary between weak topological insulators and strong topological insulators, which makes it unique in the field of materials science. Given that the surface states of topological insulators exhibit metallic properties, zirconium telluride may exhibit unconventional electrical behavior similar to that in metal / semimetal interfaces when in contact with metals. This behavior is expected to originate from the low density of states (DOS) of the interface, the linear energy dispersion characteristics and the breaking of spatial symmetry. The low density of states of semimetals can effectively reduce the Fermi level pinning effect, thereby alleviating the formation of Schottky barriers at the semiconductor interface and promoting the realization of ultra-large-scale, low-resistance contacts, which is particularly critical in transistor technology. In addition, this feature provides new possibilities for constructing low-power Dirac source rectennas and other high-performance devices. The linear dispersion characteristics enable zirconium telluride to achieve ultrafast electron transmission and high cutoff frequency in high-frequency devices, which is crucial for the design of modern high-speed electronic devices. At the same time, the breaking of spatial symmetry triggers unique electron transport phenomena, such as nonlinear Hall effect and chiral magnetic effect, which provide far-reaching research and development prospects in exploring new quantum effects and their applications. Summary of the invention

[0006] The purpose of the present invention is to provide a vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene and a preparation method thereof, which aims to solve the technical problems of traditional room temperature terahertz detectors in the prior art. Based on the unique electrical properties of topological insulator zirconium telluride, the strong nonlinear response of Dirac semimetal and topological insulator materials in the terahertz frequency range is utilized to achieve high-sensitivity and high-efficiency terahertz wave detection, as well as high-bandwidth, fast-response mixing back-end applications.

[0007] In order to achieve the above object, the technical solution of the present invention is:

[0008] A vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene, characterized in that: its structure is:

[0009] On the silicon substrate is a silicon dioxide oxide layer, on which a gold bottom electrode is firstly electron-beam lithographed, on which zirconium telluride and graphene are sequentially transferred, and on the top of the zirconium telluride and graphene, a top electrode is again electron-beam lithographed, and its structure consists of an asymmetric vertical antenna, with a source-drain distance of 50-90nm; the zirconium telluride and graphene are located between electrode channels formed by the bottom electrode and the top electrode.

[0010] The vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene is characterized in that: the silicon substrate is an intrinsic high-resistance silicon layer of the substrate, a silicon dioxide layer is grown on the intrinsic high-resistance silicon layer, the resistivity of the intrinsic high-resistance silicon layer is 19000-21000Ω·cm, and the thickness is 280-300μm; the thickness of the silicon dioxide layer is 280-330nm.

[0011] The vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene is characterized in that: the zirconium telluride is a topological insulator zirconium telluride, the topological insulator zirconium telluride is a zirconium telluride nanosheet with a thickness of 30-50nm; the graphene is a graphene nanosheet with a thickness of 20-40nm.

[0012] The vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene is characterized in that the bottom electrode and the top electrode are metal composite electrodes, the lower metal is chromium, which serves as an adhesion layer with a thickness of 10-15nm, and the upper metal is gold with a thickness of 40-50nm.

[0013] A method for preparing a vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene as described above, characterized in that it comprises the following steps:

[0014] S1. Prepare the base layer by thermal oxidation on the intrinsic high-resistance silicon as the silicon substrate.

[0015] In silicon dioxide oxide layer;

[0016] S2, preparing a metal structure layer as a bottom electrode, obtaining 10-15 nm chromium and 40-50 nm gold by electron beam evaporation;

[0017] S3, preparing single-crystalline zirconium telluride of nanometer thickness level, obtaining single-crystalline zirconium telluride by a tellurium melting method, and then using a blue tape to simply mechanically peel the single-crystalline zirconium telluride to obtain single-crystalline zirconium telluride of nanometer thickness level;

[0018] S4, transferring the nanometer-thick single-crystal zirconium telluride prepared in step S3 to the bottom electrode;

[0019] S5, preparing graphene, by decomposing methane at high temperature and depositing it on a metal catalyst copper to form a graphene film, and then using a blue tape to simply mechanically peel off the graphene film to obtain a nanometer-thick graphene film;

[0020] S6, transferring the nanometer-thick graphene prepared in step S5 onto zirconium telluride;

[0021] S6, preparing a metal structure layer as a top electrode, obtaining 10-15 nm chromium and 40-50 nm gold by electron beam evaporation;

[0022] S7. Stick the device to the PCB base, wire it, and simply package it to complete the preparation of the vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene.

[0023] The method for preparing the vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene is characterized in that: in the step S2, the layout is first designed using L-edit software, and the lower layer of evaporated metal is chromium as an adhesion layer with a thickness of 10-15nm through coating, electron beam lithography, and electron beam evaporation, and the upper layer of evaporated metal is gold with a thickness of 40-50nm, and finally the metal structure is made through traditional stripping process technology.

[0024] The advantages of the invention are:

[0025] 1) The channel material is a topological insulator. This material has a conductive surface state (semi-metallicity) and an insulating body energy band, which enables this type of material to be used in terahertz detectors with broadband and high-speed light response.

[0026] 2) Zirconium telluride and graphene materials have advantages such as environmental stability and scalability. Through point-to-point transfer technology, high-efficiency heterojunction devices with little surface contamination can be prepared.

[0027] 3) The vertical antenna structure can significantly shorten the channel length. The short channel structure can not only enhance the electron tunneling effect, but also promote ultrafast charge transfer, thereby achieving more efficient device operation. In addition, the structure also shows significant improvements in device packaging and thermal management, improving overall operating efficiency and stability.

[0028] 4) The special contact between Dirac semimetal and metal makes the lower density of states alleviate the rehybridization of electronic states, resulting in weaker Fermi level pinning effect and more adjustable Schottky barrier, while enhancing thermal emission.

[0029] 5) The linear dispersion of Dirac semimetals provides ultrafast electron transport, broadband response, and nonlinear electrical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 It is a side view schematic diagram of the vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene of the present invention.

[0031] Figure 2 It is a schematic diagram of the structure of the vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene of the present invention.

[0032] Figure 3 It is the terahertz response spectrum of the vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene under zero bias in the present invention.

[0033] Figure 4 It is a schematic diagram of the response time of the vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene under zero bias in the present invention.

[0034] Figure 5 It is a schematic diagram of the principle of enhancing thermal emission of the vertical heterojunction rectenna based on topological insulator zirconium telluride-graphene in the present invention.

[0035] Figure 6 This is a relationship diagram between the 0.3THz fundamental mixing intermediate frequency power and radio frequency of the vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene of the present invention.

[0036] Figure 7 It is a graph showing the relationship between mixing loss and frequency of the vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene in the bandwidth of 0-120GHz in the present invention. DETAILED DESCRIPTION

[0037] See also Figure 1 , 2 The present invention discloses a vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene. As shown in the figure, its structure is:

[0038] On the silicon substrate 1 is a silicon dioxide oxide layer 2, on the silicon dioxide oxide layer 2 is firstly electron beam lithographed a gold bottom electrode 3, on the bottom electrode 3 is sequentially transferred zirconium telluride 4 and graphene 5, on the top of the zirconium telluride 4 and graphene 5 is electron beam lithographed again, the top electrode 6 is composed of an asymmetric vertical antenna, the distance between the source and the drain is 50-90nm; the zirconium telluride 4 and the graphene 5 are located between the electrode channel formed by the bottom electrode 3 and the top electrode 6.

[0039] In the present invention, the silicon substrate 1 is an intrinsic high-resistance silicon layer of the substrate, on which a silicon dioxide layer 2 is grown, the resistivity of the intrinsic high-resistance silicon layer is 19000-21000Ω·cm, and the thickness is 280-300μm; the thickness of the silicon dioxide layer 2 is 280-330nm.

[0040] In the present invention, the zirconium telluride 4 is a topological insulator zirconium telluride, and the topological insulator zirconium telluride is a zirconium telluride nanosheet with a thickness of 30-50nm; the graphene 5 is a graphene nanosheet with a thickness of 20-40nm.

[0041] In the present invention, the bottom electrode 3 and the top electrode 6 are metal composite electrodes, the lower metal is chromium, which serves as an adhesion layer with a thickness of 10-15 nm, and the upper metal is gold with a thickness of 40-50 nm.

[0042] The present invention also discloses a method for preparing the vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene as described above, which comprises the following steps:

[0043] S1, preparing a base layer, preparing a silicon dioxide oxide layer 2 on an intrinsic high-resistance silicon substrate 1 by a thermal oxidation method;

[0044] S2, preparing a metal structure layer as the bottom electrode 3, obtaining 10-15 nm chromium and 40-50 nm gold by electron beam evaporation;

[0045] S3, preparing single-crystalline zirconium telluride of nanometer thickness level, obtaining single-crystalline zirconium telluride by a tellurium melting method, and then using a blue tape to simply mechanically peel the single-crystalline zirconium telluride to obtain single-crystalline zirconium telluride of nanometer thickness level;

[0046] S4, transferring the nanometer-thick single-crystal zirconium telluride prepared in step S3 onto the bottom electrode 3;

[0047] S5, preparing graphene, by decomposing methane at high temperature and depositing it on a metal catalyst copper to form a graphene film, and then using a blue tape to simply mechanically peel off the graphene film to obtain a nanometer-thick graphene film;

[0048] S6, transferring the nanometer-thick graphene prepared in step S5 onto zirconium telluride;

[0049] S6, preparing a metal structure layer as the top electrode 6, obtaining 10-15 nm chromium and 40-50 nm gold by electron beam evaporation;

[0050] S7. Stick the device to the PCB base, wire it, and simply package it to complete the preparation of the vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene.

[0051] In step S2, the layout is first designed using L-edit software, and through photolithography, electron beam evaporation, the lower layer of evaporated metal is chromium, which serves as an adhesion layer with a thickness of 10-15nm, and the upper layer of evaporated metal is gold with a thickness of 40-50nm. Finally, the metal structure is made through traditional stripping technology.

[0052] Example

[0053] This embodiment discloses a vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene and its preparation method, mechanism research and performance improvement. Specifically, it refers to using topological insulator zirconium telluride (ZrTe5) and graphene to construct a vertical van der Waals heterojunction. The new vertical rectifier antenna designed by integrated simulation efficiently focuses terahertz waves in the vertical direction to form a special metal-semimetal contact, drives the flow of unbalanced carriers, greatly reduces the dark current and noise equivalent power of the device, thereby realizing a self-driven working mode and terahertz (0.3THz) mixing imaging applications at room temperature.

[0054] The preparation method of the vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene is as follows:

[0055] 1. Substrate selection

[0056] Intrinsic high-resistance silicon and thermally grown silicon dioxide covering it are selected.

[0057] 2. Preparation and characterization of germanium bismuth telluride materials

[0058] High-quality zirconium telluride (ZrTe5) crystals were synthesized by chemical vapor transport (CVT) method. The synthesis process is as follows: high-purity zirconium powder and tellurium powder were uniformly mixed in a stoichiometric ratio of 1:5 and then heated to about 2.5×10 -2 The hot zone of the quartz tube was sealed under a vacuum degree of 1.5 Pa, and an appropriate amount of I2 (99.99%, Aladdin Chemicals) was selected as a transfer agent. The temperature of the hot zone and the cold zone was then raised to 750°C and 650°C at a rate of 1°C / min and maintained for 7 days. After natural cooling, ZrTe5 crystals were harvested in the cold zone, and then the morphology and structure of germanium, bismuth and tellurium were microscopically characterized by XRD, TEM, EDS, Raman, etc.

[0059] 3. Preparation of bottom electrode

[0060] 50-65nm Cr / Au contacts were deposited by electron beam evaporation and finally the bottom electrode was formed by lift-off process.

[0061] 4. Preparation of heterojunction

[0062] Mechanical stripping was used to strip ZrTe5 and graphene from bulk crystals to obtain nanometer-thick materials, and then ZrTe5 was transferred to the channel of the bottom electrode, and the layered graphene was transferred from the blue tape to polydimethylsiloxane (PDMS). Then, the layered graphene was transferred to ZrTe5 by dry transfer under an optical microscope on a precision transfer platform (E1-T), and one end of the two materials was in contact to complete the preparation of the heterojunction.

[0063] 5. Device preparation and stripping

[0064] The top electrode is photolithographically formed on the top of the material by electron beam lithography, and then 90-110nm Cr / Au contacts are deposited by electron beam evaporation. Finally, a room temperature topological insulator vertical heterojunction rectifier antenna with special contact of ZrTe5-graphene Dirac semimetal is formed by lift-off process ( Figure 1 and Figure 2 ).

[0065] 6. Device packaging

[0066] The device is fixed on the PCB base with an electric soldering iron, and the base and the device are welded together with an electric welder to prepare a room-temperature topological insulator vertical heterojunction rectifier antenna.

[0067] 7. Device performance test

[0068] The electrical characteristics of the device are measured using a semiconductor parameter analyzer. A microwave generator is used to generate low-frequency microwaves to generate electromagnetic waves of 0.02-0.54THz through a multiplication link. The optical response is recorded by an oscilloscope after a lock-in amplifier (LIA) and a low-noise voltage preamplifier. The specific operation is to use the pulse signal modulation frequency of the microwave source as the reference signal source of the lock-in amplifier and the oscilloscope, and at the same time connect the detector photoelectric signal amplified by the preamplifier to the input port of the lock-in amplifier. The output signal is the signal amplified again by the phase lock. This system can improve the signal-to-noise ratio and realize the automated testing functions of the response signal of the terahertz detector, the response time of the detector, etc. Figure 3 The terahertz response of the device under zero bias is shown in Figure 1. We use a high-speed oscilloscope to collect the response time. Figure 4 Response time plot of a topological insulator heterojunction terahertz detector integrated with a vertical rectenna at zero bias, typically calculated as the amount of time required for the light response of a single pulse to increase from 10% to 90% or decrease from 90% to 10%, with a device turn-on time of approximately 20ns and a turn-off time of approximately 20ns, and a complete waveform with a low signal-to-noise ratio. Figure 5The article explains that the device has a strong response mechanism in the terahertz range, and the metal-semimetal contact improves the contact resistance of the device, reduces the Fermi level pinning effect, and enhances the thermal emission of the device. Figure 6 as well as Figure 7 The device demonstrated excellent performance in frequency mixing, with a bandwidth of up to 0.3THz.

[0069] The vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene in the present invention demonstrates excellent performance indicators, including ultrafast response time (20.1ns) and wide bandwidth response (0.465THz) in the terahertz frequency range, highlighting the advantages of using metal / semi-metal contacts. These advantages include, in particular, reduced Fermi level pinning, minimal Schottky barrier effect at the graphene interface, and strong hot electron emission, confirming the excellent interface characteristics and functions of the design. In terms of heterodyne mixing, the rectifier antenna exhibits excellent mixing performance at 320GHz, highlighting its great potential in advanced mixer applications.

[0070] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made by using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene, characterized in that: Its structure is: On a silicon substrate (1) is a silicon dioxide oxide layer (2), on which a gold bottom electrode (3) is firstly formed by electron beam photolithography, zirconium telluride (4) and graphene (5) are sequentially transferred onto the bottom electrode (3), and a top electrode (6) is formed on the top of the zirconium telluride (4) and graphene (5) by electron beam photolithography again, wherein the structure consists of an asymmetric vertical antenna, and the distance between the source and the drain is 50-90nm; the zirconium telluride (4) and the graphene (5) are located between an electrode channel formed by the bottom electrode (3) and the top electrode (6).

2. The vertical heterojunction rectenna based on topological insulator zirconium telluride-graphene according to claim 1, characterized in that: The silicon substrate (1) is an intrinsic high-resistance silicon layer of the substrate, on which a silicon dioxide layer (2) is grown, the resistivity of the intrinsic high-resistance silicon layer is 19000-21000Ω·cm, and the thickness is 280-300μm; the thickness of the silicon dioxide layer (2) is 280-330nm.

3. The vertical heterojunction rectenna based on topological insulator zirconium telluride-graphene according to claim 1, characterized in that: The zirconium telluride (4) is a topological insulator zirconium telluride, and the topological insulator zirconium telluride is a zirconium telluride nanosheet with a thickness of 30-50 nm; the graphene (5) is a graphene nanosheet with a thickness of 20-40 nm.

4. The vertical heterojunction rectenna based on topological insulator zirconium telluride-graphene according to claim 1, characterized in that: The bottom electrode (3) and the top electrode (6) are metal composite electrodes, the bottom metal layer is chromium, serving as an adhesion layer, with a thickness of 10-15 nm, and the top metal layer is gold, with a thickness of 40-50 nm.

5. A method for preparing a vertical heterojunction rectenna based on topological insulator zirconium telluride-graphene as claimed in claim 1, characterized in that: It includes the following steps: S1, preparing a base layer, preparing a silicon dioxide oxide layer (2) on an intrinsic high-resistance silicon substrate (1) by a thermal oxidation method; S2, preparing a metal structure layer as a bottom electrode (3), obtaining 10-15 nm chromium and 40-50 nm gold by electron beam evaporation; S3, preparing single-crystalline zirconium telluride of nanometer thickness level, obtaining single-crystalline zirconium telluride by a tellurium melting method, and then using a blue tape to simply mechanically peel the single-crystalline zirconium telluride to obtain single-crystalline zirconium telluride of nanometer thickness level; S4, transferring the nanometer-thick single-crystal zirconium telluride prepared in step S3 onto the bottom electrode (3); S5, preparing graphene, by decomposing methane at high temperature and depositing it on a metal catalyst copper to form a graphene film, and then using a blue tape to simply mechanically peel off the graphene film to obtain a nanometer-thick graphene film; S6, transferring the nanometer-thick graphene prepared in step S5 onto zirconium telluride; S6, preparing a metal structure layer as a top electrode (6), obtaining 10-15 nm chromium and 40-50 nm gold by electron beam evaporation; S7. Stick the device to the PCB base, wire it, and simply package it to complete the preparation of the vertical heterojunction rectifier antenna based on topological insulator zirconium telluride-graphene.

6. The method for preparing a vertical heterojunction rectenna based on topological insulator zirconium telluride-graphene according to claim 5, characterized in that: In step S2, the layout is first designed using L-edit software, and through photolithography, electron beam evaporation, the lower layer of evaporated metal is chromium, which serves as an adhesion layer with a thickness of 10-15nm, and the upper layer of evaporated metal is gold with a thickness of 40-50nm. Finally, the metal structure is made through traditional stripping technology.

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