Preparation method of magnetic topological heterojunction film
阅读说明：本技术 一种磁性拓扑异质结薄膜的制备方法 (Preparation method of magnetic topological heterojunction film ) 是由 张敏 刘立刚 于 2021-07-26 设计创作，主要内容包括：本发明涉及铁磁性材料及异质结薄膜的制备技术领域,公开了一种磁性拓扑异质结薄膜的制备方法,包括以下步骤：a、Bi-(2)Se-(3)薄膜的制备：将片清洗后固定在磁控溅射设备样品台上；于高纯Ar气保护下溅射纯度为99.99％的Bi-(2)Se-(3)靶材3～5min；b、Bi-(2)Se-(3)薄膜的退火处理：将按照a步骤制备完成的Bi-(2)Se-(3)薄膜封存于石英管中,并将石英管置于管式炉中,进行退火成相处理；c、Fe-(7)Se-(8)/Bi-(2)Se-(3)异质结薄膜的制备：将经b步骤退火处理后的Bi-(2)Se-(3)薄膜固定在磁控设备样品台上,于高纯Ar气保护下溅射纯度为99.99％的Fe-(7)Se-(8)靶材5～10min；d、Fe-(7)Se-(8)/Bi-(2)Se-(3)异质结薄膜的退火处理：在400～450℃的管式炉中退火2h。本发明制备的异质结薄膜制备成本低,对环境污染少,制备工艺简单易实现,适于大批量生产。(The invention relates to the technical field of preparation of ferromagnetic materials and heterojunction thin films, and discloses a preparation method of a magnetic topological heterojunction thin film, which comprises the following steps: a. bi 2 Se 3 Preparing a film: cleaning the sheet and fixing the sheet on a sample table of magnetron sputtering equipment; sputtering Bi with the purity of 99.99 percent under the protection of high-purity Ar gas 2 Se 3 3-5 min for the target material; b. bi 2 Se 3 Annealing treatment of the film: bi prepared according to the step a 2 Se 3 Sealing the film in a quartz tube, placing the quartz tube in a tube furnace, and annealing to form a phase; c. fe 7 Se 8 /Bi 2 Se 3 Preparing a heterojunction thin film: the Bi annealed by the step b is treated 2 Se 3 The film is fixed on a sample table of a magnetic control device in high puritySputtering Fe with purity of 99.99% under protection of Ar gas 7 Se 8 The target material is used for 5-10 min; d. fe 7 Se 8 /Bi 2 Se 3 Annealing treatment of the heterojunction film: annealing for 2 hours in a tube furnace at 400-450 ℃. The heterojunction film prepared by the invention has low preparation cost, little environmental pollution and simple and easily realized preparation process, and is suitable for mass production.)
1. A preparation method of a magnetic topological heterojunction film is characterized by comprising the following steps: the method comprises the following steps:
a、Bi2Se3preparing a film: cleaning a Si (100) substrate and fixing the cleaned Si (100) substrate on a sample table of magnetron sputtering equipment; heating a Si (100) substrate, adjusting the working air pressure of a magnetron sputtering device to 0.4-0.6 Pa, and enabling the Si substrate to be heatedSputtering power is set to be 40-50W, and Bi with purity of 99.99% is sputtered under the protection of high-purity Ar gas2Se33-5 min for the target material;
b、Bi2Se3annealing treatment of the film: bi prepared according to the step a2Se3Sealing the film in vacuum at a pressure of not less than 5.0 × 10-3Pa quartz tube, and placing the quartz tube in a tube furnace for annealing and phase forming treatment;
c、Fe7Se8/Bi2Se3preparing a heterojunction thin film: the Bi annealed by the step b is treated2Se3Fixing the film on a sample table of a magnetic control device, and placing Bi2Se3Heating the film to 300-320 ℃, adjusting the working air pressure of a magnetron sputtering device to 0.4-0.6 Pa, setting the sputtering power to 50-70W, and sputtering Fe with the purity of 99.99% under the protection of high-purity Ar gas7Se8The target material is used for 5-10 min;
d、Fe7Se8/Bi2Se3annealing treatment of the heterojunction film: mixing Fe obtained in step c7Se8/Bi2Se3Sealing the heterojunction film in vacuum at a pressure of not less than 5.0 × 10-3And Pa quartz tube, placing the quartz tube in a tube furnace, and annealing at 400-450 ℃ for not less than 2 h.
2. The method of preparing a magnetic topological heterojunction thin film according to claim 1, wherein: si (100) substrate and Bi2Se3The sputtering distance of the target is as follows: 6-10 cm.
3. The method of preparing a magnetic topological heterojunction thin film according to claim 1, wherein: bi2Se3Film and Fe7Se8The sputtering distance of the target is as follows: 6-10 cm.
4. The method of preparing a magnetic topological heterojunction thin film according to claim 1, wherein: in the step b, the annealing and phase forming treatment mode is as follows: and (3) heating the tube furnace to 300-420 ℃ at the heating rate of 1.5 ℃/min, and annealing for not less than 2 hours at the temperature.
5. The method of preparing a magnetic topological heterojunction thin film according to claim 1, wherein: in the step a, heating the Si (100) substrate to 250-280 ℃.
6. The method of preparing a magnetic topological heterojunction thin film according to claim 1, wherein: in the step a, heating the Si (100) substrate to 265 ℃, adjusting the working air pressure of a magnetron sputtering device to 0.5Pa, setting the sputtering power to 45W, and sputtering Bi with the purity of 99.99 percent under the protection of high-purity Ar gas2Se3The target material is used for 4 min.
7. The method of preparing a magnetic topological heterojunction thin film according to claim 1, wherein: in step c, Bi is added2Se3Heating the film to 310 ℃, adjusting the working pressure of a magnetron sputtering device to 0.5Pa, setting the sputtering power to 60W, and sputtering Fe with the purity of 99.99 percent under the protection of high-purity Ar gas7Se8The target material is 7.5 min.
Technical Field
The invention relates to the technical field of preparation of ferromagnetic materials and heterojunction thin films, in particular to a preparation method of a magnetic topological heterojunction thin film.
Background
Bi2Se3The film is used as a typical Topological Insulator (TI) material and has wide application prospect in the field of electronic devices. In recent years, with the continuous improvement of device performance requirements, the device design is developing in the forward direction of size miniaturization, novel structure, space low dimension and energy quantization. Theory shows that reducing the thickness of a three-dimensional (3D) topological insulator material to a two-dimensional (2D) material results in a dramatic change in both its spin structure and topological properties due to this thickness. Thus, nano-sized Bi is prepared2Se3The thin film may achieve a 2D topological insulator. Meanwhile, the electronic and spinning structures of the topological insulator in the thin film state are influenced by factors such as thickness, surface, interface, ferromagnetic order and superconducting state, a plurality of interesting physical phenomena can appear, and the research on the topological insulator in the thin film state has great significance for related applications.
The TI and common insulators, semiconductors, superconductors and magnetic materials alternately grow to prepare heterojunction thin films and quantum well or quantum dot matrix devices, so that the TI surface state is more prominent, and the TI has important application potential. TI-based heterojunctions are the hottest direction for TI research in recent years. According to the report of nature journal, spin polarization neutron reflectivity experiment is adopted, and ferromagnetic insulator (EuS) and TI (Bi) are coupled in a double molecular layer system2Se3) Complex to form Bi2Se3the/EuS heterojunction is characterized in that the interface of the heterojunction generates ferromagnetism without introducing magnetic defects, breaks time reversal symmetry, and enhances magnetism of topological Surface States (SSs). Ferromagnetism extending from the interface into Bi2Se3The magnetic material is about 2nm, stable ferromagnetic long-range order is realized at a specific position of the TI surface, and a new possibility is provided for the realization of the magnetic TI and the effective control of a future spin electronic device by utilizing the spin in a topological magnetoelectric reaction regulation system in the TI. In addition, topological proximity effect also exists in TI and antiferromagnetic insulator heterostructures, and Bi is frequently studied2Se3A MnSe structure and Bi2Se3/La1-xSrxMnO3And (5) structure. T can be induced by topological nearest neighbor effectI magnetism and energy band regulation, therefore, the topological proximity effect is an important way for developing and applying spintronics.
Currently, research in the field of TI and magnetic material heterojunctions is still in the first stage, and there is still a lot of work to be perfected and determined. Among them, iron-based selenides have been widely studied due to their special crystal structure phase transition and ferromagnetism. It is reported that Fe7Se8Similar to NiAs, its cation vacancies are confined in alternating c-planes, the magnetic moments in adjacent c-planes are in opposite directions, and the magnetic moments in the same layer are in the same direction, so that different stacking modes determine Fe7Se8Two superlattice structures, a triclinic superlattice structure (4c) and an orthorhombic superlattice structure (3 c). While Fe7Se8The magnetic properties of (a) are closely related to their lattice structures. The special magnetism will determine that it is excellent in electric and magnetic transportation.
In recent years, there have been many methods for producing heterojunction thin films, such as physical methods such as magnetron sputtering, Pulsed Laser Deposition (PLD), and Molecular Beam Epitaxy (MBE), chemical methods such as Chemical Vapor Deposition (CVD), sol-gel method, and Chemical Solution Deposition (CSD), and Bi2Se3Most of the thin film research is based on MBE technology and PLD technology, but these technologies require extreme vacuum conditions, and have the problems of expensive equipment, large energy consumption and high cost, and the thin films prepared by means of CVD, CSD and the like have the problems of uniformity, compactness and the like. In recent years, with respect to Fe7Se8/Bi2Se3The preparation method of the heterojunction film is hardly reported, and the preparation method is not only simple to operate and low in cost, so that Fe7Se8/Bi2Se3The preparation process of the heterojunction thin film needs to be actively explored and optimized in order to realize high-quality Fe7Se8/Bi2Se3Industrialization and industrialization of heterojunction thin film materials.
Disclosure of Invention
The invention aims to provide a preparation method of a magnetic topological heterojunction film, which enriches preparation processes of magnetic topological heterojunction and aims to further research Fe7Se8/Bi2Se3The heterojunction performance provides relevant sample preparation technical parameters. The method can epitaxially grow Bi with good structural performance and flat surface on the Si (100) substrate2Se3Film and then preparing the finished Bi2Se3Growing high quality Fe on film7Se8The heterojunction film prepared by the method has low preparation cost, little environmental pollution and simple and easy preparation process, and is suitable for mass production.
In order to achieve the purpose, the invention adopts the following technical scheme:
a preparation method of a magnetic topological heterojunction thin film comprises the following steps:
a、Bi2Se3preparing a film: cleaning a Si (100) substrate and fixing the cleaned Si (100) substrate on a sample table of magnetron sputtering equipment; heating a Si (100) substrate to 250-280 ℃, adjusting the working pressure of a magnetron sputtering device to 0.4-0.6 Pa, setting the sputtering power to 40-50W, and sputtering Bi with the purity of 99.99% under the protection of high-purity Ar gas2Se33-5 min for the target material;
b、Bi2Se3annealing treatment of the film: bi prepared according to the step a2Se3Sealing the film in vacuum at a pressure of not less than 5.0 × 10-3Pa quartz tube, and placing the quartz tube in a tube furnace for annealing and phase forming treatment;
c、Fe7Se8/Bi2Se3preparing a heterojunction thin film: the Bi annealed by the step b is treated2Se3Fixing the film on a sample table of a magnetic control device, and placing Bi2Se3Heating the film to 300-320 ℃, adjusting the working air pressure of a magnetron sputtering device to 0.4-0.6 Pa, setting the sputtering power to 50-70W, and sputtering Fe with the purity of 99.99% under the protection of high-purity Ar gas7Se8The target material is used for 5-10 min;
d、Fe7Se8/Bi2Se3annealing treatment of the heterojunction film: mixing Fe obtained in step c7Se8/Bi2Se3Sealing the heterojunction film in vacuum at a pressure of not less than 5.0 × 10-3And Pa quartz tube, placing the quartz tube in a tube furnace, and annealing at 400-450 ℃ for not less than 2 h.
Preferably, as an improvement, the Si (100) substrate is formed with Bi2Se3The sputtering distance of the target is as follows: 6-10 cm. The film deposited in the too close area is not uniform, and the internal stress of the film is large and unstable.
Preferably, as an improvement, Bi2Se3Film and Fe7Se8The sputtering distance of the target is as follows: 6-10 cm.
Preferably, as an improvement, in the step b, the annealing phase forming treatment mode is as follows: and (3) heating the tube furnace to 300-420 ℃ at the heating rate of 1.5 ℃/min, and annealing for not less than 2 hours at the temperature.
Preferably, as an improvement, in the step a, the Si (100) substrate is heated to 250-280 ℃.
Preferably, as a modification, in the step a, the Si (100) substrate is heated to 265 ℃, the working air pressure of the magnetron sputtering equipment is adjusted to 0.5Pa, the sputtering power is set to 45W, and Bi with the purity of 99.99% is sputtered under the protection of high-purity Ar gas2Se3The target material is used for 4 min.
Preferably, as a modification, in the step c, Bi is added2Se3Heating the film to 310 ℃, adjusting the working pressure of a magnetron sputtering device to 0.5Pa, setting the sputtering power to 60W, and sputtering Fe with the purity of 99.99 percent under the protection of high-purity Ar gas7Se8The target material is 7.5 min.
The principle and the advantages of the scheme are as follows: the temperature of the substrate in the step a is 250-280 ℃, the working air pressure is 0.4-0.6 Pa, and the sputtering power is 40-50W, so that the sputtering condition is favorable for preparing Bi with uniform and compact surface2Se3A film;
the vacuum degree of the quartz tube in the step b reaches 5.0 multiplied by 10-3Pa, the annealing temperature is 300-420 ℃, the annealing time is 2h, and the annealing process is favorable for Bi2Se3Further phase formation of the film, and obtaining a high-quality single crystal film;
in step c, adding Bi2Se3Film(s)Fixing the sample on a sample rack of the magnetic control equipment again, heating the film sample to 300-320 ℃, adjusting the working pressure to 0.4-0.6 Pa, sputtering the power to 50-70W, and sputtering Fe with the purity of 99.99% under the protection of high-purity Ar gas7Se8The target material is 5-10 min, and the sputtering condition is favorable for Fe7Se8Growing the film to obtain a film sample with smooth surface and less cavities and cracks;
d step of adding Fe7Se8/Bi2Se3The heterojunction film is sealed at 5.0 × 10-3Annealing in a Pa quartz tube for 2 hours in a tube furnace at 400-450 ℃, wherein the heat treatment method can fully thermally diffuse the particles stacked on the surface of the film, is beneficial to further phase formation of the film, and obtains Fe with good crystallinity7Se8/Bi2Se3A heterojunction thin film.
In summary, 1, the invention prepares Fe7Se8/Bi2Se3In the process of heterojunction film, sputtering Bi under the condition of heating substrate by adopting magnetron sputtering method2Se3And Fe7Se8The method is favorable for growing uniform and compact film samples; the time for sputtering the film in the high-purity Ar gas is controlled to be 5-10 min, so that a 2D magnetic topological film is formed, the related performance and application development of a heterojunction are conveniently researched, and the film is prevented from being polluted by other impurities;
2. the invention prepares Fe7Se8/Bi2Se3In the process of the heterojunction film, the Si (100) substrate which is low in price and easy to obtain is used, so that the preparation cost can be effectively reduced; no toxic gas is volatilized in the preparation process, so that the harm to human bodies and the pollution to the environment are small; the whole process is simple and easy to operate, and is suitable for mass production.
3. In the invention, Fe7Se8/Bi2Se3And in the heterojunction film annealing stage, vacuum high-temperature annealing is adopted, so that the further phase formation of the film is facilitated, meanwhile, the pollution of impurities to the film is effectively avoided, and a uniform and compact high-quality film sample with few defects is obtained.
Compared with the prior invention, the invention has the following differences:
first, the preparation sequence of the invention is different, and Bi prepared first2Se3Film resputtering magnetic film Fe7Se8；
II, preparing Fe7Se8Film formation: first heating Bi2Se3The temperature of the film is 300-320 ℃, and the temperature can be ensured to be Fe7Se8In the growth process of (B), Bi2Se3The loss volatilization amount of the medium Se element is the minimum, so that when the film is formed by annealing in a tube furnace at 400-450 ℃, the formation of holes and cracks can be avoided, and a flat and compact heterojunction film is prepared;
III, Fe7Se8/Bi2Se3The heterojunction film is ferromagnetic, and Bi is heated first2Se3Sputtering Fe with purity of 99.99% under the protection of high-purity Ar gas at the temperature of 300-320 ℃, working pressure of 0.4-0.6 Pa and sputtering power of 50-70W7Se8Target material 5-10 min, then Fe7Se8/Bi2Se3The heterojunction film is sealed at 5.0 × 10-3In a Pa quartz tube, the step of annealing for 2 hours in a tube furnace at 400-450 ℃ can ensure Fe7Se8The compositional ratio of Fe and Se in the thin film was 7:8, and the resulting heterojunction was ferromagnetic.
Drawings
FIG. 1 shows Fe obtained in the first embodiment of the present invention7Se8/Bi2Se3Heterojunction thin film X-ray diffraction patterns.
FIG. 2 shows Fe obtained in the first embodiment of the present invention7Se8/Bi2Se3Scanning Electron Microscope (SEM) pictures of the heterojunction thin film.
FIG. 3 shows Fe obtained in example III of the present invention7Se8/Bi2Se3X-ray diffraction pattern of the heterojunction thin film.
FIG. 4 shows Fe obtained in example III of the present invention7Se8/Bi2Se3Scanning Electron Microscope (SEM) pictures of the heterojunction thin film.
Fig. 5 is a schematic structural diagram of a sample stage in the fourth embodiment of the present invention.
Detailed Description
The following is further detailed by way of specific embodiments:
reference numerals in the drawings of the specification include: the sample table 11, the clamping groove 12, the clamping shaft 13, the adjusting shaft 14, the main gear 15, the clamping sheet 16, the gasket 17, the pushing block 21, the top block 22, the spring 23, the top sheet 24, the rotating shaft 25 and the driven gear 26.
The first embodiment is as follows:
a preparation method of a magnetic topological heterojunction thin film comprises the following preparation steps:
a、Bi2Se3preparing a film: cleaning a Si (100) substrate and fixing the cleaned Si (100) substrate on a sample table of magnetron sputtering equipment; heating a Si (100) substrate to 250 ℃, adjusting the working air pressure of a magnetron sputtering device to 0.4Pa, setting the sputtering power to 40W, and sputtering Bi with the purity of 99.99 percent under the protection of high-purity Ar gas2Se3Target material 35min, Si (100) substrate and Bi2Se3The sputtering distance of the target material is 6 cm; the purity of the high-purity Ar gas in this example was 99.999%.
b、Bi2Se3Annealing treatment of the film: bi prepared according to the step a2Se3Sealing the film in vacuum at a pressure of not less than 5.0 × 10-3Putting the quartz tube into a tube furnace in Pa, heating the tube furnace to 300 ℃ at the heating rate of 1.5 ℃/min, annealing at the temperature for not less than 2 hours, and cooling along with the furnace after the annealing is finished;
c、Fe7Se8/Bi2Se3preparing a heterojunction thin film: the Bi annealed by the step b is treated2Se3Fixing the film on a sample table of a magnetic control device, and placing Bi2Se3Heating the film to 300 ℃, adjusting the working pressure of a magnetron sputtering device to 0.4Pa, setting the sputtering power to 50W, and sputtering Fe with the purity of 99.99 percent under the protection of high-purity Ar gas7Se8Target material for 5 min; bi2Se3Film and Fe7Se8The sputtering distance of the target is as follows: 6 cm.
d、Fe7Se8/Bi2Se3Annealing treatment of the heterojunction film: mixing Fe obtained in step c7Se8/Bi2Se3Sealing the heterojunction film in vacuum at a pressure of not less than 5.0 × 10-3And (3) putting the quartz tube into a Pa quartz tube, heating the tube furnace to 400 ℃ at the heating rate of 3 ℃/min, annealing in the tube furnace at 400 ℃ for not less than 2h, and cooling along with the furnace after the annealing is finished.
FIG. 1 shows Fe obtained in the first example7Se8/Bi2Se3Heterojunction thin film X-ray diffraction patterns. Bi is clearly observed from the figure2Se3And Fe7Se8XRD diffraction peak of (1), wherein Bi2Se3And Fe7Se8The XRD results of the above show that the film is a polycrystalline phase film, i.e. Fe grown on a Si (100) substrate under the conditions7Se8/Bi2Se3The heterojunction thin film is a polycrystalline thin film.
FIG. 2 shows Fe obtained in the first example7Se8/Bi2Se3Scanning Electron Microscope (SEM) pictures of the heterojunction thin film. As can be seen from fig. 2: the heterojunction film sample obtained by the experiment has a flat and compact surface and no holes.
Therefore, the first example can prepare Fe with good phase formation and compact and flat surface7Se8/Bi2Se3A heterojunction thin film.
Example two:
a preparation method of a magnetic topological heterojunction thin film comprises the following steps:
a、Bi2Se3preparing a film: cleaning a Si (100) substrate and fixing the cleaned Si (100) substrate on a sample table of magnetron sputtering equipment; heating a Si (100) substrate to 265 ℃, adjusting the working air pressure of a magnetron sputtering device to 0.5Pa, setting the sputtering power to 45W, and sputtering Bi with the purity of 99.99 percent under the protection of high-purity Ar gas2Se3Target material for 4 min; si (100) substrate and Bi2Se3The sputtering distance of the target is as follows: 8 cm.
b、Bi2Se3Annealing treatment of the film: will be provided withBi prepared according to the step a2Se3Sealing the film in vacuum to 5.0X 10-3Putting the quartz tube into a Pa quartz tube, heating the tube furnace to 360 ℃ at the heating rate of 1.5 ℃/min, annealing at the temperature for not less than 2 hours, and cooling along with the furnace after the annealing is finished;
c、Fe7Se8/Bi2Se3preparing a heterojunction thin film: the Bi annealed by the step b is treated2Se3Fixing the film on a sample table of a magnetic control device, and placing Bi2Se3Heating the film to 310 ℃, adjusting the working pressure of a magnetron sputtering device to 0.5Pa, setting the sputtering power to 60W, and sputtering Fe with the purity of 99.99 percent under the protection of high-purity Ar gas7Se8The target material is 7.5 min; bi2Se3Film and Fe7Se8The sputtering distance of the target is as follows: 8 cm.
d、Fe7Se8/Bi2Se3Annealing treatment of the heterojunction film: mixing Fe obtained in step c7Se8/Bi2Se3The heterojunction film is sealed at 5.0 × 10-3And (3) putting the quartz tube into a Pa quartz tube, heating the tube furnace to 425 ℃ at the heating rate of 3 ℃/min, annealing in the tube furnace at 425 ℃ for not less than 2h, and cooling along with the tube furnace after the annealing is finished.
Example three:
a preparation method of a magnetic topological heterojunction thin film comprises the following steps:
a、Bi2Se3preparing a film: cleaning a Si (100) substrate and fixing the cleaned Si (100) substrate on a sample table of magnetron sputtering equipment; heating a Si (100) substrate to 280 ℃, adjusting the working air pressure of a magnetron sputtering device to 0.6Pa, setting the sputtering power to 45W, and sputtering Bi with the purity of 99.99 percent under the protection of high-purity Ar gas2Se3Target material for 5 min; si (100) substrate and Bi2Se3The sputtering distance of the target material is 10 cm.
b、Bi2Se3Annealing treatment of the film: bi prepared according to the step a2Se3Sealing the film in vacuum at a pressure of not less than 5.0 × 10-3Putting the quartz tube into a Pa quartz tube, heating the tube furnace to 420 ℃ at the heating rate of 1.5 ℃/min, annealing for not less than 2 hours at the temperature, and cooling along with the furnace after the annealing is finished;
c、Fe7Se8/Bi2Se3preparing a heterojunction thin film: the Bi annealed by the step b is treated2Se3Fixing the film on a sample table of a magnetic control device, and placing Bi2Se3Heating the film to 320 ℃, adjusting the working pressure of a magnetron sputtering device to 0.6Pa, setting the sputtering power to 70W, and sputtering Fe with the purity of 99.99 percent under the protection of high-purity Ar gas7Se8Target material for 10 min; bi2Se3Film and Fe7Se8The sputtering distance of the target is as follows: 10 cm.
d、Fe7Se8/Bi2Se3Annealing treatment of the heterojunction film: mixing Fe obtained in step c7Se8/Bi2Se3Sealing the heterojunction film in vacuum at a pressure of not less than 5.0 × 10-3Pa quartz tube, placing the quartz tube in a tube furnace, heating the tube furnace to 450 ℃ at a heating rate of 3 ℃/min, annealing in the tube furnace at 450 ℃ for not less than 2h, and cooling along with the furnace after the annealing is finished.
FIG. 3 shows Fe obtained in the third example7Se8/Bi2Se3The X-ray diffraction pattern of the heterojunction film shows that Bi is obviously observed from the graph of figure 32Se3And Fe7Se8The result of XRD diffraction peak of (1) shows that Bi is prepared under the above conditions2Se3The film grows preferentially in the (00L) direction, the single crystal property is good, and Fe7Se8The XRD result shows that the Fe prepared by the experiment7Se8The film is polycrystalline.
FIG. 4 shows Fe obtained in the third example7Se8/Bi2Se3Scanning Electron Microscope (SEM) pictures of the heterojunction thin film. As can be seen from fig. 4: the heterojunction film sample obtained by the experiment has the advantages of uniform, flat and compact surface and no holes. Therefore, the third example can prepare Fe with good phase formation and compact and flat surface7Se8/Bi2Se3A heterojunction thin film.
Description of drawings in the first to third embodiments: the ordinate of fig. 1, 3 is the diffraction Intensity (Intensity), arbitrary units (a.u.); the abscissa is the diffraction angle 2 θ, in degrees (degree); the measurement ranges in FIGS. 2 and 4 are 1 μm each.
Example four:
example four differs from the first to third examples in that, in the steps a and c of a method for manufacturing a magnetic topological heterojunction thin film, a sample stage 11 of a magnetron apparatus is used, as shown in fig. 5, a holding groove 12 is formed on the sample stage 11, and a spacer 17 is fixed in the holding groove 12 for supporting a Si (100) substrate or Bi after annealing treatment in the step b2Se3A first clamping mechanism is arranged on two sides of the clamping groove 12 in the length direction, a second clamping mechanism is arranged on two sides of the clamping groove 12 in the width direction, and the Si (100) substrate and the Bi annealed in the step b are subjected to annealing treatment2Se3When the film is fixed on the sample table 11 of the magnetic control equipment, the first clamping mechanism and the second clamping mechanism are used for clamping in four directions, so that the stability of the whole sputtering process is improved.
In this embodiment, the first clamping mechanism includes a clamping piece 16 1-3 cm higher than the sample stage 11, the clamping piece 16 is in horizontal sliding fit with the sample stage 11, a clamping shaft 13 in horizontal sliding fit with the sample stage 11 is fixed on the clamping piece 16, an adjusting shaft 14 rotatably connected with the sample stage 11 is connected to the clamping shaft 13 through a thread, and a main gear 15 is fixed on the adjusting shaft 14 through a coaxial screw.
In this embodiment, the second clamping mechanism includes a top block 22 horizontally slidably connected to the sample stage 11, the top block 22 is 1-3 cm higher than the sample stage 11, a top plate 24 is horizontally slidably connected to the top block 22, a spring 23 is fixed between the top plate 24 and the top block 22, one side of the top block 22 away from the clamping groove 12 is an inclined surface, a pushing block 21 is matched with the inclined surface of the top block 22, the pushing block 21 is horizontally slidably connected to the sample stage 11, a rotating shaft 25 is threadedly connected to the pushing block 21, a driven gear 26 is coaxially fixed to the rotating shaft 25, and the driven gear 26 is engaged with the main gear 15.
In the scheme, the Si (100) substrate or Bi annealed in the step b is treated2Se3When the film is clamped, taking the Si (100) substrate as an example, an operator synchronously rotates the adjusting shaft 14, the adjusting shaft 14 rotates the main gear 15 and enables the clamping shaft 13 to horizontally slide in the rotating process, and when the clamping shaft 13 horizontally slides, the clamping piece 16 is pushed to move towards the substrate so as to clamp the left side and the right side of the Si (100) substrate, and by using the mode, the film can be suitable for Si (100) substrates with different lengths; when the master gear 15 rotates, the master gear 15 drives the slave gear 26 to rotate, the slave gear 26 drives the rotating shaft 25 to rotate, the rotating shaft 25 drives the pushing block 21 to horizontally slide, and the pushing block 21 extrudes the top block 22 to move towards the other two sides of the substrate, so that the top plate 24 clamps the Si (100) substrate, and the purpose of clamping is achieved. In this embodiment, it is particularly important that the top block 22 and the holding piece 16 are higher than the sample stage 11, and when performing magnetic sputtering, a certain barrier is formed around the Si (100) substrate, so that sputtering is more concentrated, and it is beneficial to prepare Bi with a uniform and dense surface2Se3A film.
The foregoing is merely an example of the present invention and common general knowledge in the art of designing and/or characterizing particular aspects and/or features is not described in any greater detail herein. It should be noted that, for those skilled in the art, without departing from the technical solution of the present invention, several variations and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent. The scope of the claims of the present application shall be determined by the contents of the claims, and the description of the embodiments and the like in the specification shall be used to explain the contents of the claims.