Preparation method of quantum device based on rattan shielding cloud association

Abstract

The invention relates to the technical field of quantum information and novel information materials, in particular to a preparation method of a quantum device based on rattan shielding cloud association, which realizes preparation of a high-density carbon nanotube array on a silicon wafer through multiple times of accurate transfer. The quantum device is constructed by using the high-density carbon nanotube array through magnetron sputtering, laser ablation or plasma etching means. The temperature for generating the near-stem effect of the quantum device constructed by the invention is no longer limited to a low-temperature environment, the remarkable near-stem effect can be observed at different temperatures by optimizing parameters such as the width and thickness of magnetron sputtering metal and the density of the high-density carbon nanotube array, and particularly, the near-stem effect can be observed at different temperatures when the width and thickness of an electrode are small. The temperature at which the resistance minimum value appears can exceed 400 Kelvin, the temperature at which the resistance minimum value appears is increased by adjusting the width and thickness of magnetron sputtering metal and the density of the high-density carbon nanotube array, and the problems of preparation of the near-rattan cloud working stably at room temperature and quantum devices associated with the near-rattan cloud are solved. And a preparation foundation is laid for quantum bit devices working at room temperature.

Description

Technical Field

[0001] The present invention relates to the technical field of quantum information and novel information materials, and in particular to a method for preparing a quantum device based on Kondo shielding cloud correlation. Background Art

[0002] With the rapid development of artificial intelligence and informatization, we have initially entered the stage of "Internet of Everything". Low-power, high-performance electronic devices and integrated circuits are the key hardware of "Internet of Everything". At present, silicon-based field-effect transistors (FETs) have entered the sub-5 nanometer technology node. The static and dynamic power consumption of high-end chips composed of tens of billions of transistors will become a bottleneck and challenge that cannot be ignored. In order to reduce the power consumption of devices and achieve high computing power, we can start from the following two aspects: (1) using new materials and new physical mechanisms to reduce the power consumption of discrete devices; (2) solving the storage wall problem, breaking the traditional von Neumann architecture, and realizing storage and computing integration. Manipulating the spin properties of electrons can effectively achieve the above two goals. Therefore, spin electronics or quantum bit technology provides a new perspective and technical path for breaking through the current technical bottlenecks in the semiconductor industry.

[0003] Due to magnetic doping, the conductivity, specific heat, and magnetic susceptibility of metals change with temperature, resulting in an extremely low resistance value at low temperatures. The appearance of this resistance minimum is related to the presence of localized magnetic moments of impurity atoms. Magnetic impurity ions exchange-couple with conduction electrons, causing the conduction electrons to be scattered by localized magnetic atoms, reversing the spin of the magnetic atoms and the conduction electrons themselves. Subsequently, the reversed magnetic atoms act on the conduction electrons. This multiple scattering process acts as an obstacle to electron motion and is the cause of the increased resistance. According to the Kondo effect, under certain conditions, the resistivity caused by spin-backward exchange scattering increases with decreasing temperature, while the resistivity caused by electron-phonon interaction decreases with decreasing temperature. Therefore, the total resistance of dilute magnetic alloys reaches a resistance minimum at low temperatures.

[0004] In order to reduce the power consumption of existing quantum devices, taking advantage of the Kondo effect to produce a minimum resistance at low temperatures is an effective way to achieve this. However, the total resistance of current quantum devices only reaches a minimum resistance at low temperatures, and there are still challenges in building quantum devices with stable performance at room temperature. This has seriously restricted the development of low-power spintronic devices or quantum bit devices. Summary of the Invention

[0005] The present invention provides a method for preparing a quantum device based on Kondo-screening cloud correlation, which is used to solve the defect in the prior art that the total resistance of quantum devices only reaches a minimum resistance value at low temperatures, and realizes the preparation of quantum devices that produce Kondo correlation at room temperature.

[0006] The present invention provides a method for preparing a quantum device based on Kondo shielding cloud correlation, comprising: preparing a high-density carbon nanotube array on a silicon wafer; spin-coating a resist on the silicon wafer with the high-density carbon nanotube array; generating a recessed area on the spin-coated resist according to a long strip design pattern, exposing the high-density carbon nanotubes in the recessed area, wherein the strips formed in the recessed area and the exposed high-density carbon nanotubes form a vertical cross structure; using magnetron sputtering to evaporate metal in the recessed area; immersing the silicon wafer after the magnetron sputtering metal evaporation in an acetone solution to strip off excess sputtered metal, thereby completing the preparation of the quantum device.

[0007] According to a method for preparing a quantum device based on Kondo shielding cloud correlation provided by the present invention, the method for preparing a quantum device based on Kondo shielding cloud correlation also includes: before using magnetron sputtering to evaporate metal in the recessed area, plasma etching is performed on the high-density carbon nanotubes exposed in the recessed area to completely open the high-density carbon nanotubes exposed in the recessed area.

[0008] According to a method for preparing a quantum device based on Kondo shielding cloud correlation provided by the present invention, plasma etching the high-density carbon nanotubes exposed in the recessed area includes: plasma etching the middle section of the high-density carbon nanotubes exposed in the recessed area, or plasma etching the end area of ​​the high-density carbon nanotubes exposed in the recessed area.

[0009] According to a method for preparing a quantum device based on Kondo shielding cloud correlation provided by the present invention, after the middle section of the high-density carbon nanotubes exposed in the recessed area is plasma etched, the recessed area is metal-deposited by magnetron sputtering. The metal strips formed by the magnetron sputtering metal are in contact with both sides of the open carbon nanotube array to form a double-sided carbon nanotube array.

[0010] After plasma etching is performed on the end areas of the exposed high-density carbon nanotubes in the recessed area, metal is evaporated in the recessed area by magnetron sputtering. The metal strips formed by the magnetron sputtering metal are in contact with one side of the open carbon nanotube array to form a single-sided carbon nanotube array.

[0011] According to a method for preparing a quantum device based on Kondo screening cloud correlation provided by the present invention, the method comprises: growing low-density carbon nanotubes on a substrate; spin-coating a polyvinyl alcohol solution doped with urea on the substrate with the low-density carbon nanotubes, and diffusion-drying to form a polyvinyl alcohol film; cutting the polyvinyl alcohol film based on the array orientation of the high-density carbon nanotubes to be obtained, and separating the polyvinyl alcohol film and the low-density carbon nanotubes from the substrate; attaching a polydimethylsiloxane film to the polyvinyl alcohol on a glass slide; The polyvinyl alcohol film is picked up for lamination, and the polyvinyl alcohol film and the low-density carbon nanotubes are transferred to the silicon wafer; the polyvinyl alcohol film and the low-density carbon nanotubes are laminated to the silicon wafer; the silicon wafer is heated to peel off the polydimethylsiloxane film and the polyvinyl alcohol film; the silicon wafer is immersed in a polyvinyl alcohol removal solution to remove the polyvinyl alcohol film; all the above steps are repeated to continuously grow the low-density carbon nanotubes on the substrate and transfer them to the silicon wafer, and based on the high-density carbon nanotube array to be obtained, high-density carbon nanotubes are built on the silicon wafer.

[0012] According to a method for preparing a quantum device based on Kondo-screened cloud correlation provided by the present invention, the high-density carbon nanotube array includes at least one of a single-walled carbon nanotube array, a multi-walled carbon nanotube array, and a carbon nanotube bundle array.

[0013] According to a method for preparing a quantum device based on Kondo-screened cloud correlation provided by the present invention, the spin coating of the resist on the silicon wafer with the high-density carbon nanotube array includes: preparing a polymethyl methacrylate solution of a required concentration and ensuring uniform mixing; placing the silicon wafer with the high-density carbon nanotube array on a spin coater, setting the spin coater speed to 1500 rpm to 2000 rpm, and evenly spin coating a first layer of polymethyl methacrylate on the silicon wafer for a spin coating time of 0.5 to 1 minute; adjusting the spin coater speed to 2500 rpm to 3000 rpm, and evenly spin coating a second layer of polymethyl methacrylate on the silicon wafer for a spin coating time of 0.5 to 1 minute; preheating an oven to 180° C., placing the silicon wafer with two layers of polymethyl methacrylate spin-coated in the oven and baking for 2 to 3 minutes; and removing the silicon wafer and naturally cooling it to room temperature.

[0014] According to a method for preparing a quantum device based on Kondo shielding cloud correlation provided by the present invention, the generation of a recessed area on the spin-coated resist according to a long strip design pattern includes: using an electron beam exposure system, an ultraviolet lithography system, an ion beam etching system or a laser etching system to design the required long strip pattern; using the electron beam exposure system, the ultraviolet lithography system, the ion beam etching system or the laser etching system to calibrate and position the resist to determine the area corresponding to the long strip pattern, and the remaining area is the exposure area; based on the calibration and positioning of the electron beam exposure system, the ultraviolet lithography system, the ion beam etching system or the laser etching system, the exposure area is exposed on the resist; the exposed silicon wafer is placed in a developer for development, so that the resist in the area corresponding to the long strip pattern is dissolved to generate a recessed area; the developed silicon wafer is transferred to a fixing solution for immersion to remove residual developer; the fixed silicon wafer is blown dry under a nitrogen flow, or wiped dry with a dust-free cloth to remove the solution on the surface of the silicon wafer.

[0015] According to a method for preparing a quantum device based on Kondo-screened cloud correlation provided by the present invention, the design width of the long strip pattern is one of 10 microns, 5 microns, 1 micron, 500 nanometers, 200 nanometers, 100 nanometers, 50 nanometers, 20 nanometers, 10 nanometers, and 5 nanometers.

[0016] The designed thickness of the long strip pattern is 15 nanometers to 100 nanometers.

[0017] According to a method for preparing a quantum device based on Kondo shielding cloud correlation provided by the present invention, the metal target material used for magnetron sputtering metal evaporation in the recessed area is at least one of molybdenum, gold, palladium, titanium, copper, iron, cobalt, and nickel.

[0018] The present invention provides a method for preparing quantum devices based on Kondo-screening cloud association. High-density carbon nanotubes are prepared and quantum devices operating stably at room temperature are constructed using methods such as laser etching and magnetron sputtering of metals. The temperature at which the Kondo effect occurs in the constructed quantum device is no longer limited to low-temperature environments. By optimizing parameters such as the width and thickness of the magnetron sputtering metal and the density of the high-density carbon nanotube array on the silicon wafer, a significant Kondo effect can be observed at different temperatures. In particular, when the electrode width and thickness are small (e.g., widths of 300 nanometers and 500 nanometers, and a thickness of 20 nanometers), the temperature at which the resistance minimum occurs can exceed 400 Kelvin. By adjusting the width and thickness of the magnetron sputtering metal and the density of the high-density carbon nanotube array on the silicon wafer, the temperature at which the resistance minimum occurs can be increased. This solves the problem of preparing Kondo clouds operating stably at room temperature and their associated quantum devices, laying a foundation for the preparation of quantum bit devices operating at room temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 It is a schematic flow chart of the method for preparing a quantum device based on Kondo-screened cloud correlation provided by the present invention.

[0021] Figure 2 It is a schematic diagram of the process of preparing a high-density carbon nanotube array on a silicon wafer provided by the present invention.

[0022] Figure 3 It is a schematic structural diagram of the double-sided carbon nanotube bundle array quantum device provided by the present invention.

[0023] Figure 4 It is a schematic structural diagram of the unilateral carbon nanotube bundle array quantum device provided by the present invention.

[0024] Figure 5 These are the resistance-temperature curves of the double-sided carbon nanotube bundle array quantum device and the single-sided carbon nanotube bundle array quantum device provided by the present invention.

[0025] Figure 6 The resistance-temperature curves of the Kondo effect of the double-sided carbon nanotube bundle array quantum device with different electrode widths provided by the present invention are shown.

[0026] Figure 7 The present invention provides a resistance-temperature curve of the Kondo effect in a double-sided carbon nanotube bundle array quantum device with different electrode thicknesses.

[0027] Figure 8 This is the resistance-temperature curve of the single-walled carbon nanotube array quantum device provided by the present invention that produces the Kondo effect.

[0028] Figure 9 It is the anisotropic magnetoresistance curve of the single-walled carbon nanotube array quantum device provided by the present invention.

[0029] Figure 10 These are the negative magnetoresistance characteristic curves of the single-walled carbon nanotube array quantum device provided by the present invention at different temperatures.

[0030] Reference numerals: 1. Silicon wafer; 2. High-density carbon nanotube array; 3. Anti-etching agent; 4. Recessed area; 5. Evaporated metal; 6. Electrode; 7. Substrate; 8. Low-density carbon nanotube; 9. Polyvinyl alcohol film; 10. Glass slide; 11. Polydimethylsiloxane film. DETAILED DESCRIPTION

[0031] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0032] The following combination Figures 1 to 10 The invention describes a method for preparing a quantum device based on Kondo-screened cloud correlation.

[0033] One embodiment of the present invention provides a method for preparing a quantum device based on Kondo-screened cloud correlation, see Figure 1 As shown, the preparation method of a quantum device based on Kondo-screened cloud correlation includes the following steps S1 to S5.

[0034] S1. Preparing a high-density carbon nanotube array 2 on a silicon wafer 1.

[0035] S2. Spin-coat a resist 3 (polymethyl methacrylate) on the silicon wafer 1 with the high-density carbon nanotube array 2 attached thereto.

[0036] S3. A recessed area 4 is generated on the spin-coated resist 3 according to a strip-shaped design pattern, and high-density carbon nanotubes are exposed in the recessed area 4. The strips formed by the recessed area and the exposed high-density carbon nanotubes form a vertical cross structure.

[0037] S4 , depositing metal 5 on the recessed area 4 by magnetron sputtering.

[0038] S5. Immerse the silicon wafer 1 after magnetron sputtering metal 5 is evaporated in an acetone solution to remove excess sputtered metal, thereby completing the preparation of the quantum device.

[0039] It can be understood that the preparation method of the quantum device based on the Kondo shielding cloud association of this embodiment prepares high-density carbon nanotubes and constructs a quantum device that operates stably at room temperature by means of laser etching, magnetron sputtering metal, etc. The temperature at which the Kondo effect occurs in the constructed quantum device is no longer limited to a low-temperature environment. By optimizing parameters such as the width and thickness of the magnetron sputtering metal (electrode 6 width and thickness) and the density of the high-density carbon nanotube array on the silicon wafer, a significant Kondo effect can be observed at different temperatures. In particular, when the electrode 6 width is small (such as 300 nanometers and 500 nanometers in width and 20 nanometers in thickness), the temperature at which the resistance minimum occurs can exceed 400 Kelvin. By adjusting the width and thickness of the magnetron sputtering metal and the density of the high-density carbon nanotube array on the silicon wafer, the temperature at which the resistance minimum occurs can be increased, thereby solving the problem of preparing Kondo clouds and related quantum devices that operate stably at room temperature, and laying a foundation for the preparation of quantum bit devices operating at room temperature.

[0040] Furthermore, in other embodiments, according to a method for preparing a quantum device based on Kondo shielding cloud correlation provided by the present invention, the method for preparing a quantum device based on Kondo shielding cloud correlation also includes: before using magnetron sputtering to evaporate the metal 5 on the recessed area 4, plasma etching is performed on the high-density carbon nanotubes exposed in the recessed area 4, so that the high-density carbon nanotubes exposed in the recessed area are completely opened.

[0041] It is understood that in the quantum device fabricated using the Kondo-screening cloud-related quantum device fabrication method of the present invention, the opening of the carbon nanotube bundle is a key factor. This opening of the carbon nanotube bundle is achieved through magnetron sputtering, laser ablation, or plasma etching, with the goal of partially or completely opening the carbon nanotubes, thereby forming the desired quantum device structure. In the aforementioned embodiment, only magnetron sputtering was used to evaporate the metal 5, achieving partial opening of the carbon nanotube bundle. This embodiment adds a plasma etching step, combining plasma etching with magnetron sputtering coating to achieve complete opening of all carbon nanotubes in the carbon nanotube bundle. This embodiment effectively achieves opening of the carbon nanotube bundle and constructs a quantum device with excellent performance, exhibiting significant Kondo effect and anisotropic magnetoresistance. This not only improves device manufacturing precision but also ensures its stability and reliability in practical applications.

[0042] It should be understood that plasma etching of the exposed high-density carbon nanotubes in the recessed area includes: plasma etching of the middle section of the exposed high-density carbon nanotubes in the recessed area; and plasma etching of the end section of the exposed high-density carbon nanotubes in the recessed area. After plasma etching of the middle section of the exposed high-density carbon nanotubes in the recessed area, magnetron sputtering is performed to evaporate metal. The metal strips formed by the magnetron sputtering are in contact with both sides of the open carbon nanotube array, forming a double-sided carbon nanotube array (such as Figure 3 As shown); plasma etching is performed on the end region of the high-density carbon nanotubes exposed in the concave region, and then magnetron sputtering is performed to evaporate metal. The metal strips formed by the magnetron sputtering are in contact with one side of the open carbon nanotube array to form a single-sided carbon nanotube array (as shown); Figure 4 shown).

[0043] In some embodiments of the method for preparing a quantum device based on Kondo screened cloud correlation of the present invention, see Figure 2 As shown, the preparation of a high-density carbon nanotube array 2 on a silicon wafer 1 includes the following steps S11 to S17.

[0044] S11 , growing low-density carbon nanotubes 8 based on the substrate 7 .

[0045] S12, spin-coating the urea-doped polyvinyl alcohol solution on the substrate 7 with the low-density carbon nanotubes 8, and diffusion-drying to form a polyvinyl alcohol film 9; S13, cutting the polyvinyl alcohol film 9 based on the array orientation of the high-density carbon nanotubes to be obtained, and separating the polyvinyl alcohol film 9 and the low-density carbon nanotubes 8 from the substrate 7; S14, attaching a polydimethylsiloxane film 11 to the glass slide 10 to pick up the polyvinyl alcohol film 9, and transferring the polyvinyl alcohol film 9 and the low-density carbon nanotubes 8 to the silicon wafer 1; S15, laminating the polyvinyl alcohol film 9 and the low-density carbon nanotubes 8 to the silicon wafer 1; heating the silicon wafer 1 to peel off the polydimethylsiloxane film 11 and the polyvinyl alcohol film 9; S16, soaking the silicon wafer 1 in a polyvinyl alcohol removal solution to remove the polyvinyl alcohol film 9; S17, repeat all the above steps, continuously grow low-density carbon nanotubes 8 on the substrate 7 and transfer them to the silicon wafer 1, and build high-density carbon nanotubes on the silicon wafer 1 based on the high-density carbon nanotube array 2 to be obtained.

[0046] High-density carbon nanotube arrays include at least one of single-walled carbon nanotube arrays, multi-walled carbon nanotube arrays, and carbon nanotube bundle arrays. In some specific examples, taking the transfer of single-walled carbon nanotube arrays as an example, low-density carbon nanotubes 8 are first grown on a sapphire substrate 7. A urea-doped polyvinyl alcohol (PVA) solution is then spin-coated at 1600 rpm onto the sapphire substrate 7 with the low-density carbon nanotubes 8. The urea-doped PVA solution is then dried by natural diffusion to form a PVA film 9. Next, the PVA film 9 is cut into a specific shape (rectangular or square) based on the orientation of the carbon nanotube array using a tool or laser etching. The PVA film 9 and the low-density carbon nanotubes 8 are then peeled from the substrate 7 along the edges of the cut PVA film 9. Finally, the PVA film 9 is picked up and transferred via a polydimethylsiloxane film 11 on a glass slide 10, allowing the PVA film 9 and the low-density carbon nanotubes 8 to be transferred to a silicon wafer 1. Next, the polyvinyl alcohol film 9 and low-density carbon nanotubes 8 are oriented and bonded to the silicon wafer 1 for at least 1 minute. Simultaneously, the silicon wafer 1 is heated to 70°C. Once the temperature of the silicon wafer 1 rises, the polydimethylsiloxane film 11 is peeled off from the polyvinyl alcohol film 9, leaving the polyvinyl alcohol film 9 and low-density carbon nanotubes 8 bonded to the silicon wafer 1. Finally, the silicon wafer 1, along with the polyvinyl alcohol film 9 and low-density carbon nanotubes 8, is immersed in a polyvinyl alcohol removal solution to remove the polyvinyl alcohol film 9 from the silicon wafer 1, leaving only the low-density carbon nanotubes 8, thus completing the transfer of the low-density carbon nanotubes 8. This process is repeated repeatedly, transferring the low-density carbon nanotubes 8 multiple times, ultimately yielding a high-density carbon nanotube pattern on the silicon wafer 1.

[0047] It can be understood that the method of preparing a high-density carbon nanotube array 2 on a silicon wafer 1 according to this embodiment forms a high-density carbon nanotube array by transferring low-density carbon nanotubes 8. The transfer equipment required is simple, the operation steps are very convenient, the transfer cost is low, and the carbon nanotube pickup rate, transfer efficiency, and success rate are all close to 100%. The low-density carbon nanotube array 8 can be efficiently and stably transferred onto the silicon wafer 1. The resulting high-density carbon nanotube array 2 has a complete morphology and a clean surface. This method is a post-processing method for increasing the density of the carbon nanotube array. The method of preparing a high-density carbon nanotube array 2 on a silicon wafer 1 according to this embodiment is applicable to the transfer of single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, mixed carbon nanotubes with different tube counts, and single-walled carbon nanotube bundles, double-walled carbon nanotube bundles, multi-walled carbon nanotube bundles, and mixed carbon nanotube bundles with different tube counts to form high-density carbon nanotubes or high-density carbon nanotubes.

[0048] High-density carbon nanotube arrays (CNTs) have significant application potential in field-effect transistors (FETs). These horizontally aligned, high-density arrays not only enable efficient carrier transport but also overcome the current-carrying capacity limitations of individual CNTs, laying the foundation for high-performance nanoelectronic devices. Due to their one-dimensional quantum confinement, they exhibit extremely high carrier mobility, theoretically enabling faster switching speeds and lower power consumption while overcoming short-channel effects.

[0049] Furthermore, the polyvinyl alcohol film 9 and low-density carbon nanotubes 8 are transferred to the silicon wafer 1 using a movable fixture. The movable fixture includes a chuck with a removable glass slide 10 fixed thereto. The side of the glass slide 10 facing away from the chuck is attached with a polydimethylsiloxane film 11 for picking up the polyvinyl alcohol film 9. In some examples, the substrate 7 is placed on a first sample stage and the silicon wafer 1 is placed on a second sample stage. The chuck is adapted to transition between a first position and a second position, the first position being above the first sample stage and the second position being above the second sample stage. In the first position, the chuck is adapted to move toward or away from the first sample stage to pick up the polyvinyl alcohol film 9 on the substrate 7. In the second position, the chuck is adapted to move toward or away from the second sample stage to adhere the picked-up polyvinyl alcohol film 9 to the silicon wafer 1. A heating device is provided on the second sample stage, adapted to heat the silicon wafer 1 to peel the polydimethylsiloxane film 11 from the polyvinyl alcohol film 9.

[0050] In some embodiments of the method for fabricating a quantum device based on Kondo-screened cloud correlation of the present invention, spin coating the resist 3 on the silicon wafer 1 with the high-density carbon nanotube array 2 includes the following steps S21 - S2 .

[0051] S21, prepare polymethyl methacrylate (resist 3) solution of required concentration and ensure it is evenly mixed; S22, placing the silicon wafer 1 with the high-density carbon nanotube array 2 on a spin coater, setting the spin coater speed to 1500 rpm to 2000 rpm, and evenly spin-coating a first layer of polymethyl methacrylate (resist 3) on the silicon wafer 1 for 0.5 to 1 minute; S23, adjusting the spin coater speed to 2500 rpm to 3000 rpm, and evenly spin-coating a second layer of polymethyl methacrylate (resist 3) on the silicon wafer 1 for 0.5 to 1 min; S24, preheating the oven to 180°C, placing the silicon wafer 1 spin-coated with two layers of polymethyl methacrylate into the oven and baking for 2-3 minutes; S25, take out the silicon wafer 1 and cool it naturally to room temperature.

[0052] It will be appreciated that in this embodiment, two layers of PPMA adhesive (resist 3) are spin-coated on the silicon wafer 1 with the high-density carbon nanotube array 2. The primary function of the first layer of PPMA adhesive is to provide a uniform base coating on the surface of the silicon wafer 1. Since the carbon nanotube array may have some surface irregularities, the first layer of PPMA adhesive helps fill these minor bumps and indentations, creating a relatively flat base. This first layer of PPMA adhesive provides initial protection for the carbon nanotubes, preventing unnecessary damage or contamination during subsequent processes (such as exposure, development, and etching). Furthermore, the first layer of PPMA adhesive helps improve the adhesion between the subsequent second layer of PPMA adhesive and the surface of the silicon wafer 1. By increasing the contact area and improving the surface properties, the second layer of PPMA adhesive is more firmly attached to the silicon wafer 1. The second layer of PPMA adhesive is primarily used for subsequent high-resolution electron beam exposure and patterning. A higher rotational speed (e.g., 3000 rpm) can make the PPMA adhesive layer thinner and more uniform, thereby achieving higher resolution and precision during electron beam exposure. The thinner second layer of PPMA adhesive can reduce edge roughness during development and etching, which is particularly important for quantum devices that require precise control of the size and shape of the carbon nanotube openings. The double-layer PPMA adhesive structure can provide a larger process window, making it easier to obtain ideal pattern quality and consistency in the subsequent exposure, development, and etching steps. By adjusting the thickness of the two layers of PPMA adhesive, the efficiency and effectiveness of the entire process can be optimized while ensuring pattern quality.

[0053] In some embodiments of the method for preparing a quantum device based on Kondo-screened cloud correlation of the present invention, generating a recessed area on the spin-coated resist 3 according to a strip-shaped design pattern includes the following steps S31 to S36.

[0054] S31. Use an electron beam exposure system to design the required long strip pattern.

[0055] S32, using an electron beam exposure system to perform calibration and positioning on the resist 3, determining the area corresponding to the long strip pattern, and the remaining area is the exposure area.

[0056] S33 . Based on the calibration and positioning of the electron beam exposure system, electron beam exposure is performed on the exposure area on the resist 3 .

[0057] S34 , placing the exposed silicon wafer 1 into a developer for development, so that the resist 3 in the area corresponding to the long strip pattern is dissolved, and a recessed area 4 is formed.

[0058] S35 , transferring the developed silicon wafer 1 to a fixing solution for immersion to remove the residual developing solution.

[0059] S36 , drying the fixed silicon wafer 1 under a nitrogen flow, or wiping it with a dust-free cloth to remove the solution on the surface of the silicon wafer 1 .

[0060] Specifically, the silicon wafer 1, which has been spin-coated with two layers of PPMA adhesive and a high-density carbon nanotube array 2, is first ensured to be completely dry and clean. The desired stripe pattern is then designed using the dedicated software for the electron beam lithography system. Various widths (e.g., 10 microns, 5 microns, 1 micron, 500 nanometers, 200 nanometers, 100 nanometers, 50 nanometers, 20 nanometers, 10 nanometers, 5 nanometers, etc.) and thicknesses (15 nanometers to 100 nanometers) can be set to meet specific device requirements.

[0061] Exposure operation: Before actual exposure, ensure that the electron beam exposure system (Vistec EBPG 5000) has been correctly calibrated (the calibration position will form a Figure 3 The double-sided carbon nanotube bundle array quantum device shown in the figure forms a Figure 4 The unilateral carbon nanotube bundle array quantum device shown in the figure is prepared by adjusting exposure parameters based on the size of the silicon wafer 1. The prepared silicon wafer 1 is placed on the sample stage of the electron beam exposure system and secured in place. Electron beam exposure is performed according to the designed strip pattern. During exposure, the electron beam scans the surface of the silicon wafer 1 along a predetermined path, causing chemical changes in the PPMA adhesive in the exposed areas. The exposure dose and time need to be optimized based on the specific PPMA adhesive type and thickness, and the optimal parameters are usually determined experimentally.

[0062] Development: Prepare a 1:3 volume ratio of methyl isobutyl ketone (MIBK) to isopropyl alcohol (IPA) solution. For example, mix 1 part MIBK with 3 parts IPA. Immerse the exposed silicon wafer 1 in this MIBK / IPA mixture and develop for 1 minute. During development, the PPMA adhesive not exposed by the electron beam dissolves, while the exposed areas remain. The dissolved PPMA adhesive forms recessed areas 4. Gently shake the container during development to ensure even contact between the solution and the surface of the wafer 1, promoting development.

[0063] Fixing: Quickly transfer the developed wafer 1 to the isopropyl alcohol solution and soak for 1 minute. This step removes any residual developer and prevents further development. Gently shake the container during the fixing process to ensure sufficient contact between the wafer 1 and the isopropyl alcohol.

[0064] As can be understood, patterning using an electron beam lithography system (such as the Vistec EBPG 5000) is a key step in quantum device fabrication. This involves exposing, developing, and fixing the resist 3, creating recessed areas 4 for subsequent magnetron sputtering of metal. These meticulous steps and key technical techniques yield high-quality, elongated patterns that can be used in subsequent plasma etching and metal evaporation processes. This effectively enables precise patterning of quantum devices based on high-density carbon nanotube arrays 2, ensuring the performance and reliability of the resulting device.

[0065] It should be understood that, in the above embodiments, an electron beam exposure system is used to construct the quantum device. Of course, the device can also be prepared by using an ultraviolet lithography system, an ion beam etching system or a laser etching system.

[0066] In some specific embodiments of the method for preparing a quantum device based on Kondo shielding cloud correlation of the present invention, plasma etching the high-density carbon nanotubes exposed in the recessed area 4 includes: setting the carrier gas flow rate of the argon plasma etcher to 10 standard cubic centimeters per minute and the power to 100 watts, placing the silicon wafer 1 on the sample stage of the argon plasma etcher, and using the argon plasma etcher to plasma etch the high-density carbon nanotubes exposed in the recessed area 4 to remove the exposed high-density carbon nanotubes.

[0067] Specifically, first ensure that the silicon wafer 1 is completely dry and clean after electron beam exposure, development, and fixing. Check the status of the plasma etcher (Etchlab 200) to confirm that it is operating normally and is ready for etching. Set the etching parameters: Set the flow rate of argon (Ar) to 10 standard cubic centimeters per minute (sccm). Argon is an inert gas that is used as a carrier gas during plasma etching to help generate high-energy ions to bombard the sample surface. Set the RF power to 100 watts. The higher power can provide enough energy to generate a high-density plasma, thereby effectively etching the exposed carbon nanotubes. Set the etching time to 1 minute. This time can be adjusted according to actual needs to achieve the ideal etching depth and accuracy.

[0068] The prepared silicon wafer 1 is placed on the sample stage of the plasma etcher and secured in place, ensuring good contact between the wafer 1 and the electrode 6. The chamber is closed and the vacuum pump is activated to evacuate the chamber to the desired operating pressure (typically a few millitorr or less). Once the chamber reaches the desired vacuum level, the argon valve is opened to allow argon to flow into the chamber, adjusting the flow rate to the set value (10 sccm). The RF power supply is turned on to ionize the argon gas in the chamber, forming a plasma. High-energy ions bombard the surface of the silicon wafer 1, initiating etching of the exposed carbon nanotubes and removing the exposed, high-density carbon nanotubes. By employing these precise steps and key technical techniques, the argon plasma etcher can effectively etch the exposed carbon nanotube arrays within the pattern, ensuring the high quality and performance of the final quantum device.

[0069] In some embodiments of the preparation method of quantum devices based on Kondo shielding cloud correlation of the present invention, the metal target material used for magnetron sputtering evaporation of metal 5 in the recessed area 4 is at least one of molybdenum, gold, palladium, titanium, copper, iron, cobalt, and nickel. Taking magnetron sputtering evaporation of metal 5 molybdenum as an example, first ensure that the surface of the recessed area 4 is clean and dust-free (ultrasonic cleaning or chemical cleaning can be used to remove surface contaminants), and confirm that the magnetron sputtering equipment (including vacuum pump, power supply, etc.) is in good condition, especially the target material (molybdenum) should be installed correctly and without obvious damage or oxidation. After closing the chamber of the magnetron sputtering equipment, start the vacuum pump and reduce the pressure in the chamber to a working pressure range suitable for sputtering (usually between 10 -3 to 10 -5 Before deposition officially begins, perform a short pre-sputtering (e.g., 5-10 minutes) to remove any impurities or oxide layers that may be present on the target surface, ensuring the quality of subsequent deposition. Adjust the sputtering power supply to 300 watts, introduce an appropriate amount of process gas (typically argon), and adjust its flow rate to achieve the desired pressure level (generally within the range of 1-5 Pascals). Once all conditions are met, start the sputtering process. Control the time and power density to regulate the deposition rate and achieve the desired film thickness (30 nm in this example). Once the desired deposition thickness is reached, turn off the power, stop the gas supply, and allow the chamber to gradually return to atmospheric pressure. Remove the coated silicon wafer 1 from the equipment to avoid scratching or contaminating the newly deposited molybdenum layer. Through the above steps, a 30-nanometer-thick molybdenum film can be deposited in the recessed area 4 on the silicon wafer 1 using magnetron sputtering technology. The sample coated with metal molybdenum is then immersed in acetone for 1 hour to remove the remaining PPMA glue (resist 3) and peel off the excess metal (mainly referring to the metal molybdenum sputtered on the resist 3).

[0070] The performance of the quantum device prepared by the preparation method of the quantum device based on Kondo-screened cloud correlation of the present invention is described below in combination with specific example experimental data.

[0071] Example 1: A quantum device is constructed by magnetron sputtering and plasma etching on a silicon wafer 1 with a high-density carbon nanotube bundle array.

[0072] Two layers of PPMA glue (molecular weight 950k) were spin-coated on a silicon wafer 1 with a high-density carbon nanotube bundle array at rotation speeds of 2000 rpm and 3000 rpm, respectively. After the glue was evenly applied, the wafer was baked at 180°C for 2 minutes. An electron beam exposure system (model: Vistec EBPG 5000) was used to expose the designed long strip pattern. The pattern was developed in a 1:3 volume ratio methyl isobutyl ketone / isopropyl alcohol mixed solution for 1 minute, and then fixed in an isopropyl alcohol solution for 1 minute. The exposed carbon nanotube bundle array in the pattern was etched using argon plasma. The plasma etcher model was Etchlab 200. The etching conditions were 10 sccm argon gas, 100 watts power, and an etching time of 1 minute. Metal 5 molybdenum was evaporated using magnetron sputtering at a sputtering power of 300 W to a thickness of 30 nanometers. The sample coated with metal molybdenum was immersed in acetone for 1 hour to strip off the excess metal, completing the preparation of the quantum device.

[0073] The resistance-temperature curve and magnetoresistance curve of carbon nanotube bundle quantum device were measured using comprehensive physical property measurement system (PPMS).

[0074] Figure 5 Schematic diagram of a double-sided carbon nanotube bundle array quantum device ( Figure 3 ) and unilateral carbon nanotube bundle array quantum devices ( Figure 4 ) A comparison of the resistance-temperature curves of the double-sided and single-sided carbon nanotube bundle array quantum devices with those of ordinary pure metals shows that both the double-sided and single-sided carbon nanotube bundle array quantum devices fabricated using the method in Schematic 1 exhibit the Kondo effect at room temperature, reaching a minimum resistance at around 300 Kelvin.

[0075] Figure 6 The resistance-temperature curves of the Kondo effect in double-sided carbon nanotube bundle array quantum devices with different electrode 6 widths are shown (the molybdenum strip widths are 300 nm, 500 nm, 1 μm, 2 μm, 3 μm, and 5 μm, respectively). Figure 6It can be clearly observed in the comparative curves shown that when the density of carbon nanotube bundles is constant and the thickness of the molybdenum strips is constant, as the width of the molybdenum strips decreases, the temperature at which the resistance minimum occurs increases. The resistance minimum of quantum devices with molybdenum strip widths of 300 nanometers and 500 nanometers exceeds 400 Kelvin; the resistance minimum of quantum devices with molybdenum strip widths of 1 micron appears at 380 Kelvin; and when the molybdenum strip width is 5 microns, no Kondo effect is observed in the quantum device. Specifically, when the thickness of the molybdenum strips remains unchanged, their width is changed. As the width decreases, the bilateral carbon nanotube bundle array has two quantum states: one with a Kondo temperature of (T k = 107.8 ±2.7 K), which is the spin correlation state caused by the overlap of Kondo screening clouds; a Kondo temperature is (T k = 15.8 ± 2.0 K), which is the state of a single Kondo-shielded cloud.

[0076] Figure 7 The resistance-temperature curves of the Kondo effect in a double-sided carbon nanotube bundle array quantum device with different electrode 6 thicknesses are shown (the thickness of the molybdenum strips are 15 nm, 20 nm, 30 nm, and 50 nm, respectively). Figure 7 It can be clearly observed in the schematic comparison curve that when the density of carbon nanotube bundles and the width of molybdenum strips are constant, as the thickness of the molybdenum strips decreases, the temperature at which the resistance minimum occurs increases. The resistance minimum of the quantum device with a molybdenum strip thickness of 15 nanometers exceeds 400 Kelvin; the resistance minimum of the quantum device with a molybdenum strip thickness of 20 nanometers appears at 370.5 Kelvin; even if the thickness of the molybdenum strips is 30 nanometers and 50 nanometers, the temperature at which the resistance minimum occurs is much higher than the traditional extremely low temperature. Specifically, when the width of the molybdenum strips remains unchanged, its thickness is changed. As the thickness decreases, there are two quantum states in the bilateral carbon nanotube bundle array: one with a Kondo temperature (T k = 107.8 ± 2.7 K), which is the spin correlation state caused by the overlap of Kondo screening clouds; a Kondo temperature is (T k =15.8 ± 2.0 K), which is the state of a single Kondo-shielded cloud.

[0077] Example 2: A quantum device is constructed by magnetron sputtering and plasma etching on a silicon wafer 1 with a high-density single-walled carbon nanotube array. The process is the same as in Example 1, except that the high-density carbon nanotube bundle array is replaced with a high-density single-walled carbon nanotube array.

[0078] The resistance-temperature curve and magnetoresistance curve of high-density single-walled carbon nanotube quantum devices were measured using a comprehensive physical property measurement system (PPMS).

[0079] Figure 8The resistance-temperature curve of the single-walled carbon nanotube array quantum device with the Kondo effect is shown (the horizontal axis is temperature, the vertical axis is resistance, the width and thickness of the molybdenum strip are 500 nanometers and 20 nanometers respectively). Figure 8 It can be seen that quantum devices based on high-density single-walled carbon nanotubes have the Kondo effect. By increasing the density of carbon nanotubes in the array, the temperature of the minimum resistance of the quantum device can be further increased.

[0080] Figure 9 The anisotropic magnetoresistance curve of the single-walled carbon nanotube array quantum device is shown (the horizontal axis is the magnetic field intensity and the vertical axis is the resistance). Figure 9 In the figure, the direction perpendicular to the substrate plane is the z direction, the direction parallel to the carbon nanotube bundle is the x direction, and the direction along the long side of the molybdenum strip is the y direction. The quantum device exhibits obvious magnetic anisotropy. Under the action of the magnetic field in the x direction, the quantum device exhibits a negative magnetoresistance effect, while the other two directions exhibit a positive magnetoresistance effect.

[0081] Figure 10 The negative magnetoresistance curves of a single-walled carbon nanotube array quantum device under an x-direction magnetic field at different temperatures are shown. It can be seen that the negative magnetoresistance effect persists at 50 Kelvin. By increasing the density of carbon nanotubes in the array, the temperature at which the negative magnetoresistance effect disappears can be further increased.

[0082] Examples 1 and 2 show that the quantum device prepared by the preparation method of the quantum device based on the Kondo shielding cloud association of the present invention can meet the Kondo effect at room temperature and have a minimum resistance. By increasing the density of carbon nanotubes in the array and changing the electrode width, the temperature at which the quantum device has a minimum resistance and the temperature at which the negative magnetoresistance effect of the quantum device disappears can be further increased, thereby solving the problem of preparing Kondo clouds and their interrelated quantum devices that can operate stably at room temperature, and laying a foundation for the preparation of quantum bit devices that operate at room temperature.

[0083] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for preparing a quantum device based on Kondo-screened cloud correlation, characterized in that: include: Preparation of high-density carbon nanotube arrays on silicon wafers; Spin coating a resist on the silicon wafer with the high-density carbon nanotube array; Generating a recessed area on the spin-coated resist according to a strip-shaped design pattern, exposing high-density carbon nanotubes in the recessed area, and forming a vertical cross structure with the exposed high-density carbon nanotubes through the strips formed in the recessed area; Depositing metal on the recessed area by magnetron sputtering; The silicon wafer after the magnetron sputtering metal evaporation is immersed in an acetone solution to remove excess sputtered metal, thereby completing the preparation of the quantum device.

2. The method for preparing a quantum device based on Kondo-screened cloud correlation according to claim 1, characterized in that: Also includes: Before the metal is evaporated in the recessed area by magnetron sputtering, the high-density carbon nanotubes exposed in the recessed area are subjected to plasma etching to completely open the high-density carbon nanotubes exposed in the recessed area.

3. The method for preparing a quantum device based on Kondo-screened cloud correlation according to claim 2, characterized in that: Plasma etching the exposed high-density carbon nanotubes in the recessed region includes plasma etching the middle region of the exposed high-density carbon nanotubes in the recessed region, or plasma etching the end region of the exposed high-density carbon nanotubes in the recessed region.

4. The method for preparing a quantum device based on Kondo-screened cloud correlation according to claim 3, characterized in that: After plasma etching the middle section of the high-density carbon nanotubes exposed in the recessed area, metal is deposited in the recessed area by magnetron sputtering, so that the metal strips formed by the magnetron sputtering metal are in contact with both sides of the open carbon nanotube array to form a double-sided carbon nanotube array; After plasma etching is performed on the end areas of the exposed high-density carbon nanotubes in the recessed area, metal is evaporated in the recessed area by magnetron sputtering. The metal strips formed by the magnetron sputtering metal are in contact with one side of the open carbon nanotube array to form a single-sided carbon nanotube array.

5. The method for preparing a quantum device based on Kondo-screened cloud correlation according to any one of claims 1 to 4, characterized in that: The method of preparing a high-density carbon nanotube array on a silicon wafer comprises: Low-density carbon nanotubes are grown on a substrate; Spin-coating a urea-doped polyvinyl alcohol solution on the substrate with the low-density carbon nanotubes, and diffusion-drying the solution to form a polyvinyl alcohol film; Based on the array orientation of the high-density carbon nanotubes to be obtained, cutting the polyvinyl alcohol film, and separating the polyvinyl alcohol film and the low-density carbon nanotubes from the substrate; The polyvinyl alcohol film is attached to a glass slide and picked up by laminating a polydimethylsiloxane film, and the polyvinyl alcohol film and the low-density carbon nanotubes are transferred to the silicon wafer; Laminating the polyvinyl alcohol film and the low-density carbon nanotubes to the silicon wafer; heating the silicon wafer to peel off the polydimethylsiloxane film and the polyvinyl alcohol film; soaking the silicon wafer in a polyvinyl alcohol removal solution to remove the polyvinyl alcohol film; Repeat all the above steps to continuously grow the low-density carbon nanotubes on the substrate and transfer them to the silicon wafer. Based on the high-density carbon nanotube array to be obtained, high-density carbon nanotubes are built on the silicon wafer.

6. The method for preparing a quantum device based on Kondo-screened cloud correlation according to claim 5, characterized in that: The high-density carbon nanotube array includes at least one of a single-walled carbon nanotube array, a multi-walled carbon nanotube array, and a carbon nanotube bundle array.

7. The method for preparing a quantum device based on Kondo-screened cloud correlation according to any one of claims 1 to 4, characterized in that: The step of spin coating the resist on the silicon wafer with the high-density carbon nanotube array includes: Prepare polymethyl methacrylate solution of desired concentration and ensure it is evenly mixed; The silicon wafer with the high-density carbon nanotube array is placed on a spin coater, the spin coater speed is set to 1500 rpm to 2000 rpm, and a first layer of polymethyl methacrylate is evenly spin-coated on the silicon wafer for 0.5 to 1 min; Adjust the spin coater speed to 2500 rpm to 3000 rpm, and evenly spin-coat a second layer of polymethyl methacrylate on the silicon wafer for 0.5 to 1 min; Preheat the oven to 180° C., place the silicon wafer spin-coated with two layers of polymethyl methacrylate into the oven and bake for 2-3 minutes; The silicon wafer was taken out and naturally cooled to room temperature.

8. The method for preparing a quantum device based on Kondo-screened cloud correlation according to any one of claims 1 to 4, characterized in that: The step of generating a recessed area on the spin-coated resist according to a strip-shaped design pattern comprises: Designing the required long strip pattern using an electron beam exposure system, an ultraviolet lithography system, an ion beam etching system, or a laser etching system; Use an electron beam exposure system, an ultraviolet lithography system, an ion beam etching system or a laser etching system to perform calibration and positioning on the resist to determine the area corresponding to the long strip pattern, and the remaining area is the exposure area; Exposing the exposure area on the resist based on calibration positioning of an electron beam exposure system, an ultraviolet lithography system, an ion beam etching system, or a laser etching system; placing the exposed silicon wafer into a developer for development, so that the resist in the area corresponding to the long strip pattern is dissolved to form a recessed area; Transferring the developed silicon wafer to a fixing solution for immersion to remove residual developer; The fixed silicon wafer is blown dry under a nitrogen flow, or wiped dry with a dust-free cloth to remove the solution on the surface of the silicon wafer.

9. The method for preparing a quantum device based on Kondo-screened cloud correlation according to claim 8, characterized in that: The design width of the long strip pattern is one of 10 micrometers, 5 micrometers, 1 micrometer, 500 nanometers, 200 nanometers, 100 nanometers, 50 nanometers, 20 nanometers, 10 nanometers, and 5 nanometers; The designed thickness of the long strip pattern is 15 nanometers to 100 nanometers.

10. The method for preparing a quantum device based on Kondo screened cloud correlation according to any one of claims 1 to 4, characterized in that: The metal target material used for depositing metal on the recessed area by magnetron sputtering is at least one of molybdenum, gold, palladium, titanium, copper, iron, cobalt, and nickel.

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