Doped silicon nanowire and preparation device, preparation method and application thereof

Abstract

The invention belongs to the technical field of nano material preparation. The invention provides a doped silicon nanowire as well as a preparation device, a preparation method and application thereof, an aluminum chloride generation chamber is arranged in a main reaction chamber of the preparation device and is communicated with a silicon source inlet, a catalytic source inlet and a doping source inlet, and aluminum chloride, the silicon source, the catalytic source and the doping source are mixed in an inner cavity of the main reaction chamber by utilizing the preparation device to prepare the doped silicon nanowire. The method comprises the following steps: adding a silicon source into a catalytic source, carrying out a reaction, reducing the silicon source and the catalytic source into monatomic silicon and a metal catalyst by aluminum monochloride in the reaction process, catalyzing the monatomic silicon by the metal catalyst to generate a silicon nanowire, and carrying out in-situ doping on the silicon nanowire by a doping source to obtain a doped silicon nanowire; the scheme is simple and convenient, doped silicon nanowires can be generated on a large scale, the doping type and the doping effect are controllable, and the improvement effect of doping on the performance of the silicon nanowires is ensured.

Description

Technical Field

[0001] The invention belongs to the field of nano material preparation, and relates to a doped silicon nanowire and a preparation device, a preparation method and an application thereof. Background Art

[0002] At present, when the silicon material reaches the nanoscale, a series of physical effects will appear, such as quantum size effect, macroscopic quantum tunneling effect, Coulomb blockade effect, small size effect and volume effect, etc. Silicon nanowires are one-dimensional nanomaterials with all the physical effects of nanomaterials. They are the primary representative of semiconductor nanomaterials. They have their own special properties in the semiconductor field and physical properties different from bulk silicon materials, such as field emission, visible photoluminescence and thermal conductivity, etc. They have a good application market in sensors, field effect transistors, photocatalysis, lithium batteries and photovoltaic cells.

[0003] Doping silicon nanowires is to dope trivalent elements such as boron, aluminum, gallium or indium into the silicon lattice during the preparation of silicon nanowires to generate holes with positive charge, i.e., P-type silicon nanowires; or dope pentavalent elements such as phosphorus or arsenic into the silicon lattice to generate surplus electrons with negative charge, i.e., N-type silicon nanowires. Doping can improve the conductivity of silicon nanowires. In lithium battery applications, using P-type or N-type silicon nanowires can reduce the internal resistance of the battery and improve the rate characteristics of the lithium battery. In photovoltaic cell applications, it can be used to make P / N junctions as the emitter of the battery to convert photoelectrons into majority carriers, i.e., current; or to make high and low concentration junctions to reduce contact resistance and increase the minority carrier lifetime, thereby improving the photoelectric conversion efficiency of photovoltaic cells.

[0004] CN101817643A discloses a novel silicon nanowire doping method, which includes first sputtering a nano-gold layer on a glass substrate, forming gold nanoclusters after chemical etching, then introducing silane and hydrogen to grow silicon nanowires, then injecting Fe ions or other rare magnetic elements by ion implantation, and then magnetically activating the silicon nanowires doped with rare magnetic impurities by annealing. The doping concentration of the doped nanowires can be compensated and adjusted by the electron spin splitting characteristics of the rare magnetic impurities under the action of an electric field.

[0005] CN1841659A discloses a method for manufacturing silicon nanowires, which comprises forming a regular pattern of micro-grooves with multiple micro-cavities on a substrate, and then forming a second dopant layer and a first dopant layer thereon on the silicon substrate, and then forming a metal layer by deposition, heating the metal layer in the micro-grooves to condense to form an effective catalyst, and then using a thermal process to grow doped nanowires between the catalyst and the silicon substrate.

[0006] The above two methods for in-situ preparation of doped silicon nanowires are relatively limited, especially the methods of ion implantation and microstructure manufacturing of substrates are also required, and the general applicability is poor. CN101973517A discloses a method for preparing a low-doped porous silicon nanowire array, which is to etch a low-doped single-crystal silicon wafer with high-concentration hydrofluoric acid and etching solution to obtain a doped silicon nanowire array. This treatment method has a greater impact on the doping elements, and the product obtained is in the form of a sheet like a silicon substrate, and its subsequent processing and application will be limited.

[0007] More specifically, taking the application of doped silicon nanowires in solar cells as an example, the current common method is to perform regional selective doping on the cell, which requires a high-temperature diffusion process and can only dope the entire surface of the substrate. It also requires the use of semiconductor electronic processes such as masking and etching, which has many steps and is complex and time-consuming. Although local doping can be performed by ion implantation such as the above-mentioned CN101817643A, this method causes serious damage to the battery and seriously affects the battery conversion efficiency, and subsequent repairs need to be performed through annealing and other processes. Therefore, the above methods cannot meet the requirements of flexible processing and application of doped silicon nanowires.

[0008] Since there is little research on the preparation of doped silicon nanowires in the prior art, it is of great significance and value to develop a manufacturing solution for in-situ doped silicon nanowires that can achieve low cost, large scale, controllable doping amount, and excellent doping effect. Summary of the invention

[0009] In view of the problems existing in the prior art, the purpose of the present invention is to provide a doped silicon nanowire and a preparation device, a preparation method and an application thereof. An aluminum chloride generating chamber is arranged in the main reaction chamber of the preparation device, and is connected with silicon source, catalytic source and doping source inlets. The preparation device is used to mix aluminum chloride, silicon source, catalytic source and doping source in the inner cavity of the main reaction chamber and react. During the reaction, aluminum chloride reduces the silicon source and the catalytic source to elemental silicon and elemental titanium, and elemental titanium catalyzes elemental silicon to generate silicon nanowires. At the same time, the doping source in-situ dopes the silicon nanowires to obtain doped silicon nanowires. The scheme is simple and convenient, and can generate doped silicon nanowires on a large scale. The doping type and doping effect are controllable, thereby ensuring the improvement effect of doping on the performance of silicon nanowires.

[0010] To achieve this object, the present invention adopts the following technical solutions:

[0011] In the first aspect, the present invention provides a device for preparing doped silicon nanowires, comprising a main reaction chamber, wherein an aluminum chloride generating chamber is provided in the main reaction chamber, the inner cavity of the aluminum chloride generating chamber is connected to the inner cavity of the main reaction chamber, and aluminum chloride is released into the inner cavity of the main reaction chamber; the main reaction chamber is also provided with a raw material inlet, and the raw material inlet is used to provide a silicon source, a catalytic source and a doping source into the inner cavity of the main reaction chamber.

[0012] The present invention sets an aluminum chloride generating chamber in the main reaction chamber, utilizes the generated aluminum chloride and introduces it into the inner cavity of the main reaction chamber, uses it as a reducing component to reduce the silicon source introduced into the inner cavity of the main reaction chamber, and simultaneously reduces the catalytic source to generate a metal catalyst. Under the influence of the metal catalyst, the reduced silicon grows into silicon nanowires. At the same time, because the main reaction chamber is also connected to the doping source inlet, the doping source simultaneously existing in the inner cavity of the main reaction chamber in-situ dopes the grown silicon nanowires, thereby obtaining doped silicon nanowires. The device has a simple structure, is easy to construct, and can support low-cost, large-scale and stable output of doped silicon nanowires.

[0013] The following are preferred technical solutions of the present invention, but are not intended to be limitations of the technical solutions provided by the present invention. Through the following technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved and realized.

[0014] As a preferred technical solution of the present invention, the aluminum chloride generating chamber is provided with an aluminum trichloride vapor inlet, the inner cavity of the aluminum chloride generating chamber is provided with an aluminum container, and the aluminum chloride generating chamber is provided with an aluminum chloride outlet for connecting to the inner cavity of the reaction chamber and releasing aluminum chloride.

[0015] Preferably, the aluminum chloride vapor inlet is connected to the aluminum chloride vaporization chamber.

[0016] Preferably, the aluminum container comprises a quartz boat filled with metallic aluminum.

[0017] The present invention preferably vaporizes aluminum trichloride at a certain vaporization temperature so that aluminum trichloride vapor enters an aluminum monochloride generation chamber. At this time, at the reaction temperature provided by the main reaction chamber, metallic aluminum vaporizes to generate aluminum vapor, and the aluminum trichloride vapor can react with the aluminum vapor to generate gaseous aluminum monochloride, which enters the inner cavity of the main reaction chamber along with the carrier gas.

[0018] Preferably, the main reaction chamber comprises a quartz tube furnace.

[0019] Preferably, the raw material inlet includes an independently arranged reaction material inlet and a doping source inlet, and the reaction material inlet is used to provide a mixture of a silicon source and a catalytic source into the inner cavity of the main reaction.

[0020] Preferably, a reaction material inlet pipe for introducing both the silicon source and the catalyst source is provided on the reaction material inlet and extends into the inner cavity of the main reaction chamber.

[0021] Preferably, one end of the reaction material inlet pipe away from the inner cavity of the main reaction chamber is connected to a reaction material mixing vaporization chamber of the silicon source and the catalytic source.

[0022] Preferably, the doping source inlet is provided with a doping source inlet tube, and extends into the inner cavity of the main reaction chamber.

[0023] Preferably, the main reaction chamber is also provided with an exhaust gas outlet.

[0024] In a second aspect, the present invention provides a method for preparing doped silicon nanowires, using the preparation device described in the first aspect, the method comprising:

[0025] Aluminum chloride is released into the inner cavity of the main reaction chamber through the aluminum chloride generating chamber, and at the same time, a silicon source, a catalytic source and a doping source are provided into the inner cavity of the main reaction chamber through a raw material inlet, so that the aluminum chloride, the silicon source, the catalytic source and the doping source are mixed in the inner cavity of the main reaction chamber and react to generate doped silicon nanowires.

[0026] The invention allows aluminum chloride, a silicon source, a catalytic source and a doping source to react, so that the reaction process is a VLS mechanism.

[0027] Specifically, the silicon source, such as silicon tetrachloride, reacts with the aluminum chloride to generate gaseous silicon atoms; the doping source, such as the gaseous doping source diborane, is thermally decomposed at a selected temperature to generate boron atoms; the catalytic source, such as titanium tetrachloride, reacts with aluminum chloride to generate "gaseous titanium atoms" as catalytic active components. On the one hand, due to the low saturated vapor pressure of titanium, it is most likely to condense into droplets. As silicon atoms and doping atoms dissolve into titanium metal droplets and form Si-Ti alloys, the alloy droplets continue to grow, and under the action of gravity, the droplets settle and adhere to the inner wall or the collection vessel.

[0028] When there is no Al element, since the three-phase coexistence point of Si-Ti alloy is 1330°C, under the reaction conditions, the alloy is solid, and the "gas phase titanium atoms" are transformed into solid metal catalysts as catalytic active components. When the concentration of silicon and doping atoms in the alloy exceeds their saturated solubility, the doping atoms crystallize, precipitate and grow doped silicon nanowires from the bottom of the droplet along with silicon. This growth process is called the VSS mechanism (V refers to gaseous Si atoms, S refers to solid metal catalysts, and S refers to solid silicon nanowires). Due to the solubility of Si in solid metal catalysts and the limitations of migration speed, the VSS mechanism is not the best mechanism for growing silicon nanowires.

[0029] The present invention controls the evaporation temperature of aluminum trichloride and the flow rate of its carrier gas to cause the remaining aluminum vapor to exist in the aluminum chloride production chamber and enter the main reaction chamber with the carrier gas, and participate in the process of condensation of catalytic active components to form droplets. Due to the introduction of Al, the composition of the droplets is a Ti-Al-Si ternary alloy, and the liquid phase limit temperature can be as low as 595°C. By selecting appropriate reaction conditions, the growth of silicon nanowires can be carried out through the VLS mechanism (V refers to gaseous Si atoms, L refers to liquid metal catalysts, and S refers to solid silicon nanowires).

[0030] For example, the VLS mechanism process described in the present invention includes: during the process of mixing and reacting aluminum monochloride, silicon source silicon tetrachloride, catalytic source titanium tetrachloride and doping source diborane in the inner cavity of the main reactor, aluminum monochloride reduces the silicon source and the catalytic source to gaseous silicon atoms and gaseous titanium atoms respectively, and the doping source decomposes at the reaction temperature to generate gaseous doping atoms; as the reaction proceeds, the concentrations of gaseous silicon atoms, gaseous titanium atoms and gaseous doping atoms continue to increase, and when the concentration of gaseous titanium atoms exceeds the saturated vapor pressure of titanium at the reaction temperature, the gaseous titanium atoms and aluminum vapor condense to form alloy droplets; gaseous silicon atoms and doping atoms dissolve into the alloy droplets, causing the alloy droplets to grow continuously, and under the action of gravity, the alloy droplets settle and adhere to the inner wall or the collecting vessel; when the concentration of silicon in the alloy droplets exceeds the saturated solubility, silicon together with the doping atoms crystallizes from the bottom of the alloy droplets and grows into doped silicon nanowires.

[0031] In the above VLS mechanism, the size and number of droplets play an important role in the morphology of silicon nanowires. The larger the droplets, the thicker the silicon nanowires, and the more droplets there are, the shorter the silicon nanowires. Therefore, by adjusting the material ratio and the reaction temperature, professional technicians will be able to skillfully control the morphology, thickness, length and doping concentration of silicon nanowires within 1*10 17 ~1*10 22 atm / cm 3 within the range.

[0032] As a preferred technical solution of the present invention, the method for preparing the aluminum monochloride includes: in an aluminum monochloride reaction chamber, aluminum trichloride vapor is mixed and reacted with aluminum metal to generate aluminum monochloride gas.

[0033] The present invention heats metal aluminum to a suitable temperature through a gas phase reaction to generate a sufficient amount of Al vapor, which reacts with AlCl3 vapor to generate gaseous aluminum monochloride (AlCl).

[0034] Preferably, the aluminum chloride vapor is generated in an aluminum chloride vaporization chamber and introduced into an aluminum chloride generation chamber via a carrier gas.

[0035] Preferably, the flow rate of the carrier gas loaded with aluminum chloride vapor is 50 to 300 sccm, for example, 50 sccm, 70 sccm, 90 sccm, 110 sccm, 130 sccm, 150 sccm, 170 sccm, 190 sccm, 210 sccm, 230 sccm, 250 sccm, 270 sccm or 300 sccm, but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0036] Preferably, the generation temperature of the aluminum chloride vapor is 160-200°C, for example, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C or 200°C, but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0037] As a preferred technical solution of the present invention, the silicon source includes silicon tetrachloride.

[0038] Preferably, the catalytic source comprises a metal halide.

[0039] Preferably, the metal halide comprises any one of titanium chloride, silver chloride, cupric chloride, cuprous chloride, ferric chloride, ferrous chloride, gold chloride, zinc chloride or lead chloride, or a combination of at least two thereof. Typical but non-limiting examples of the combination include a combination of zinc chloride and lead chloride, a combination of silver chloride and cupric chloride, a combination of cuprous chloride and cupric chloride, a combination of ferric chloride and ferrous chloride, a combination of gold chloride and titanium chloride, a combination of titanium chloride and cupric chloride, a combination of titanium chloride and zinc chloride or a combination of zinc chloride and cupric chloride, preferably titanium tetrachloride.

[0040] Preferably, the molar ratio of the silicon source to the catalytic source is (10-50):1, for example 10:1, 12:1, 14:1, 16:1, 18:1, 20:1, 22:1, 24:1, 26:1, 28:1, 30:1, 32:1, 34:1, 36:1, 38:1, 40:1, 42:1, 44:1, 46:1, 48:1 or 50:1, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0041] Preferably, the silicon source and the catalytic source are mixed in a reactant mixing vaporization chamber and maintained at a constant temperature of 18 to 50°C, for example, 18°C, 20°C, 22°C, 24°C, 26°C, 28°C, 30°C, 32°C, 34°C, 36°C, 38°C, 40°C, 42°C, 44°C, 46°C, 48°C or 50°C, etc., but are not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0042] Preferably, the silicon source and the catalyst source are both introduced into the inner cavity of the main reaction chamber through a reaction material inlet pipe arranged at the reaction material inlet from a reaction material mixing vaporization chamber through a carrier gas.

[0043] Preferably, the flow rate of the carrier gas loaded with a silicon source and / or a catalytic source is 20 to 300 sccm, for example, 20 sccm, 40 sccm, 50 sccm, 70 sccm, 90 sccm, 110 sccm, 130 sccm, 150 sccm, 170 sccm, 190 sccm, 210 sccm, 230 sccm, 250 sccm, 270 sccm or 300 sccm, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are equally applicable.

[0044] Preferably, when the catalytic source is insoluble in silicon tetrachloride, it is introduced into the inner cavity of the main reaction chamber through a powder feeding device.

[0045] As a preferred technical solution of the present invention, the doping source includes a P-type doping source or an N-type doping source.

[0046] Preferably, the P-type doping source includes borane, boron powder, or any one of aluminum, gallium or indium metal elements or a combination of at least two of them. Typical but non-limiting examples of the combination include a combination of borane and boron powder, a combination of aluminum metal element and gallium metal element, a combination of aluminum metal element and indium metal element, or a combination of gallium metal element and indium metal element.

[0047] Preferably, the N-type doping source includes phosphine, phosphorus powder or elemental arsenic, or any one of antimony or bismuth metal elements or a combination of at least two of them. Typical but non-limiting examples of the combination include a combination of phosphine and phosphorus powder, a combination of phosphorus powder and elemental arsenic, or a combination of elemental antimony metal and elemental bismuth metal.

[0048] Preferably, the doping source is a gaseous substance.

[0049] Preferably, when the doping source is a gaseous substance, it is introduced into the inner cavity of the main reaction chamber through a doping source inlet pipe arranged on the doping source inlet by a carrier gas;

[0050] Preferably, when the doping source is a liquid substance, a quartz container containing the liquid doping source is placed in the inner cavity of the main reaction chamber.

[0051] Preferably, when the doping source is a solid substance, a quartz container containing the solid doping source is placed in the inner cavity of the main reaction chamber.

[0052] Preferably, the flow rate of the carrier gas carrying the gaseous dopant source is 20 to 100 sccm, for example, 20 sccm, 30 sccm, 40 sccm, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm or 100 sccm, but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0053] Preferably, the molar ratio of the gaseous doping source to the carrier gas is 1:(1-500), for example 1:1, 1:2, 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:50, 1:70, 1:100, 1:150, 1:200, 1:250, 1:300, 1:350, 1:400, 1:450 or 1:500, etc., but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0054] Preferably, the concentration of the doping element in the doped silicon nanowire is 1*10 17 ~1*10 22 atms / cm 3 , for example 1*10 17 atms / cm 3 , 5*10 17 atms / cm 3 , 1*10 18 atms / cm 3 , 5*10 18 atms / cm 3 , 1*10 19 atms / cm 3 , 5*10 19 atms / cm 3 , 1*10 20 atms / cm 3 , 5*10 20 atms / cm 3 , 1*10 21 atms / cm 3 , 5*10 21 atms / cm 3 or 1*10 22 atms / cm 3 The above numerical range is not limited to the above numerical values, and other numerical values ​​not listed are also applicable.

[0055] Taking boron doping as an example, the optimal atomic concentration of boron in silicon wire is 1*10 21 atms / cm 3, that is, 10 to the power of 21 boron atoms per cubic centimeter. This is equivalent to a boron-silicon molar ratio of 1:50, which is equivalent to a molar ratio of diborane to silicon tetrachloride of 1:100. Those skilled in the art should select the doping range of 1*10 according to the needs of the doping element and doping concentration. 17 ~1*10 22 atms / cm 3 , calculate and control the molar ratio of the amount of doping source used to the amount of silicon source used.

[0056] As a preferred technical solution of the present invention, the insulation temperature of the reaction is 900-1100°C, for example, 900°C, 920°C, 940°C, 960°C, 1000°C, 1020°C, 1040°C, 1060°C, 1080°C or 1100°C, but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0057] The selection of the reaction temperature of the present invention should consider not only the energy consumption but also the concentration of aluminum vapor. Aluminum has a high boiling point (t b The reaction temperature is set in the range of 900-1100°C, which is suitable for the reduction of silicon tetrachloride and the generation of silicon nanowires. If the temperature is too low, the concentration of aluminum monochloride produced is too low, which affects the growth rate of silicon nanowires. If the temperature is too high, it may affect the precipitation of silicon crystals, which is not conducive to the growth of silicon nanowires.

[0058] Preferably, the heating rate of the reaction is 3 to 7°C / min, for example, 3°C / min, 3.5°C / min, 4°C / min, 4.5°C / min, 5°C / min, 5.5°C / min, 6°C / min, 6.5°C / min or 7°C / min, but is not limited to the listed values, and other values ​​not listed within the above numerical range are also applicable.

[0059] Preferably, the reaction time is 30 to 300 min, for example, 30 min, 50 min, 70 min, 90 min, 100 min, 120 min, 140 min, 160 min, 180 min, 200 min, 220 min, 240 min, 260 min, 280 min or 300 min, but is not limited to the listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0060] Preferably, the carrier gas comprises argon.

[0061] As a preferred technical solution of the present invention, the method comprises the following steps:

[0062] S1 uses a quartz tube furnace as the main reaction chamber, raises the temperature of the main reaction chamber to 900-1100°C at a heating rate of 3-7°C / min, and maintains the temperature stable;

[0063] At the same time, the temperature of the aluminum chloride vaporization chamber is set to 160-200° C., aluminum chloride is vaporized into aluminum chloride vapor, and argon gas is used as a carrier gas at a flow rate of 50-300 sccm to carry the aluminum chloride vapor into the aluminum chloride generation chamber, so that the aluminum chloride vapor is mixed with aluminum vapor generated by metal aluminum carried in a quartz boat set in the aluminum chloride generation chamber to react, generate aluminum chloride gas, and release it into the inner cavity of the main reaction chamber;

[0064] At the same time, silicon tetrachloride is used as a silicon source and titanium tetrachloride is used as a catalyst source, mixed in a molar ratio of (10-50):1 and placed in a reaction material mixing vaporization chamber, the reaction material mixing vaporization chamber is set to a constant temperature of 18-50° C., and argon is used as a carrier gas at a flow rate of 20-300 sccm to pass the mixed liquid loaded with silicon tetrachloride and titanium tetrachloride into the inner cavity of the main reaction chamber;

[0065] At the same time, diborane is used as a doping source, argon is used as a carrier gas, and the molar ratio of the two is controlled to be 1:(1-500), and the loaded diborane is introduced into the inner cavity of the main reaction chamber at a flow rate of 20-100 sccm;

[0066] S2 When aluminum chloride, silicon source, catalyst source and doping source are mixed in the inner cavity of the main reactor, the reaction is carried out for 30 to 300 minutes, and the concentration of the doping element generated is 1*10 17 ~1*10 22 atm / cm 3 doped silicon nanowires.

[0067] In a third aspect, the present invention provides a doped silicon nanowire obtained according to the preparation method described in the second aspect.

[0068] In a fourth aspect, the present invention provides applications of the doped silicon nanowires described in the third aspect, wherein the applications include sensors, field effect transistors, photocatalysis, lithium-ion batteries or photovoltaic cells.

[0069] Compared with the prior art solutions, the present invention has at least the following beneficial effects:

[0070] The main reaction chamber of the preparation device provided by the present invention is provided with an aluminum chloride generation chamber, and is connected with inlets of a silicon source, a catalytic source and a doping source. The preparation device is used to mix aluminum chloride, a silicon source, a catalytic source and a doping source in the inner cavity of the main reaction chamber and react. During the reaction, aluminum chloride reduces the silicon source and the catalytic source to elemental silicon and a metal catalyst. The metal catalyst catalyzes the elemental silicon to generate silicon nanowires. At the same time, the doping source in-situ dopes the silicon nanowires, thereby obtaining doped silicon nanowires.

[0071] The preparation method of the present invention can realize the simultaneous crystallization and precipitation of doping atoms and silicon atoms, and does not need to apply additional energy to implant the doping source into silicon, thereby avoiding harmful damage to the silicon lattice; because it is in-situ doping, its concentration can be adjusted within a large range, and the doping atoms are evenly distributed in the silicon nanowires, and the preparation efficiency is high;

[0072] The present invention can obtain doped silicon nanowires with uniform doping and high doping concentration. High-concentration doping greatly improves the conductivity of silicon. Therefore, when the obtained doped silicon nanowires are used to make electrodes and used in lithium-ion batteries, the internal resistance of the battery can be effectively reduced, thereby improving the rate performance and cycle stability of the battery. In addition, the doped silicon nanowires with high doping concentration can be used as a doping source itself, combined with high-temperature diffusion or laser doping and other process methods to achieve doping of silicon wafer substrates, especially regional selective doping, thereby eliminating complex and cumbersome process steps such as masking and etching. Therefore, the doped silicon nanowires obtained by the present invention can have broad application prospects in the production of solar cells and electronic devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0073] Figure 1 is a schematic structural diagram of the device for preparing doped silicon nanowires according to the present invention;

[0074] In the figure: 1-main reaction chamber, 2-aluminum chloride production chamber, 3-aluminum chloride vaporization chamber, 4-aluminum container, 5-reaction material inlet pipe, 6-reaction material mixing vaporization chamber, 7-doping source inlet pipe, 8-exhaust gas outlet;

[0075] Figure 2 3 is a scanning electron microscope image of the doped silicon nanowires obtained in Example 1. DETAILED DESCRIPTION

[0076] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0077] The following examples and comparative examples all use the following doped silicon nanowire preparation device: Figure 1 As shown, the preparation device comprises:

[0078] A main reaction chamber 1, wherein the main reaction chamber 1 is a quartz tube furnace;

[0079] An aluminum chloride generating chamber 2 is provided in the main reaction chamber 1, and the aluminum chloride generating chamber 2 is provided with an aluminum chloride vapor inlet and connected to an aluminum chloride vaporization chamber 3, and an aluminum container 4 is provided in the inner cavity of the aluminum chloride generating chamber 2, and the aluminum container 4 is a quartz boat filled with metal aluminum, and the aluminum chloride generating chamber 2 is provided with an aluminum chloride outlet for connecting to the inner cavity of the main reaction chamber 1 and releasing aluminum chloride;

[0080] The inner cavity of the main reaction chamber 1 is also connected to a reaction material inlet and a doping source inlet; a reaction material inlet pipe 5 for introducing a silicon source and a catalytic source is provided on the reaction material inlet, and extends into the inner cavity of the main reaction chamber 1; an end of the reaction material inlet pipe 5 away from the inner cavity of the main reaction chamber 1 is connected to a reaction material mixing vaporization chamber 6 for the silicon source and the catalytic source; a doping source inlet pipe 7 is provided on the doping source inlet, and extends into the inner cavity of the main reaction chamber 1; the doping source inlet is a gaseous doping source inlet, and the doping source inlet pipe 7 is a gaseous doping source inlet pipe;

[0081] The main reaction chamber 1 is also provided with an exhaust gas outlet 8 .

[0082] Example 1

[0083] This embodiment provides a method for preparing P-type doped silicon nanowires, the method comprising the following steps:

[0084] S1 uses a quartz tube furnace as the main reaction chamber, raises the temperature of the main reaction chamber to 1060°C at a heating rate of 5°C / min, and maintains the temperature stable;

[0085] At the same time, the temperature of the aluminum chloride vaporization chamber is set to 180° C., aluminum chloride is vaporized into aluminum chloride vapor, and argon gas is used as a carrier gas at a flow rate of 180 sccm to carry the aluminum chloride vapor into the aluminum chloride generation chamber, so that it reacts with the metal aluminum carried in the quartz boat set in the aluminum chloride generation chamber to generate aluminum chloride gas, and release it into the inner cavity of the main reaction chamber;

[0086] At the same time, silicon tetrachloride was used as a silicon source and titanium tetrachloride was used as a catalyst source, mixed at a molar ratio of 30:1 and placed in a reaction material mixing vaporization chamber, the reaction material mixing vaporization chamber was set to a constant temperature of 28° C., and argon was used as a carrier gas at a flow rate of 160 sccm to carry a mixed liquid of silicon tetrachloride and titanium tetrachloride into the inner cavity of the main reaction chamber;

[0087] At the same time, diborane (B2H6) was used as a doping source, and argon was used as a carrier gas to control the molar ratio of the two to be 1:25. The loaded diborane was introduced into the inner cavity of the main reaction chamber at a flow rate of 60 sccm.

[0088] S2 When aluminum chloride, silicon source, catalyst source and doping source are mixed in the inner cavity of the main reactor, the reaction is carried out for 150 minutes to generate P-type doped silicon nanowires with a theoretical doping concentration of 1*10 21 atm / cm 3 .

[0089] Figure 2 This is a scanning electron microscope image of the P-type doped silicon nanowire obtained in Example 1. It can be seen from the figure that the P-type doped silicon nanowire has the basic characteristics of conventional silicon nanowires. The wire diameter distribution is uniform. 20 silicon wires were taken for wire diameter measurement and the average wire diameter and deviation were 122±20nm. The morphology of the silicon nanowire is monodisperse, without entanglement and knotting, which is convenient for subsequent use.

[0090] Example 2

[0091] This embodiment provides a method for preparing N-type doped silicon nanowires. The method adjusts the temperature of the aluminum chloride vaporization chamber from 180°C to 200°C, uses phosphine instead of diborane as a doping source, and the theoretical doping concentration of the generated N-type doped silicon nanowires is 5*10 20 atm / cm 3 Except for the above, other conditions are exactly the same as those in Example 1.

[0092] Example 3

[0093] This embodiment provides a method for preparing P-type doped silicon nanowires, the method comprising the following steps:

[0094] S1 uses a quartz tube furnace as the main reaction chamber, raises the temperature of the main reaction chamber to 1100°C at a heating rate of 7°C / min, and maintains the temperature stable;

[0095] At the same time, the temperature of the aluminum chloride vaporization chamber is set to 200° C., aluminum chloride is vaporized into aluminum chloride vapor, and argon gas is used as a carrier gas at a flow rate of 300 ccm to carry the aluminum chloride vapor into the aluminum chloride generation chamber, so that it reacts with the metal aluminum carried in the quartz boat set in the aluminum chloride generation chamber to generate aluminum chloride gas, and release it into the inner cavity of the main reaction chamber;

[0096] At the same time, silicon tetrachloride was used as a silicon source and titanium tetrachloride was used as a catalyst source, mixed at a molar ratio of 50:1 and placed in a reaction material mixing vaporization chamber, the reaction material mixing vaporization chamber was set to a constant temperature of 50° C., and argon was used as a carrier gas at a flow rate of 300 sccm to carry a mixed liquid of silicon tetrachloride and titanium tetrachloride into the inner cavity of the main reaction chamber;

[0097] At the same time, diborane was used as a doping source, argon was used as a carrier gas, and the molar ratio of the two was controlled to be 1:500. The loaded diborane was introduced into the inner cavity of the main reaction chamber at a flow rate of 100 sccm.

[0098] When aluminum chloride, silicon source, catalytic source and doping source are mixed in the inner cavity of the main reactor, the reaction is carried out for 300 minutes to generate P-type doped silicon nanowires with a theoretical doping concentration of 2*10 17 atm / cm 3 .

[0099] Example 4

[0100] This embodiment provides a method for preparing P-type doped silicon nanowires. In addition to adjusting the temperature of the main reaction chamber from 1060°C to 850°C and the carrier gas flow rate of the doping source from 60 sccm to 20 sccm in step S1, the theoretical doping concentration of the generated P-type doped silicon nanowires is 3*10 22 atm / cm 3 Except for the above, other conditions are exactly the same as those in Example 1.

[0101] Example 5

[0102] This embodiment provides a method for preparing P-type doped silicon nanowires. In the preparation method, in addition to adjusting the temperature of the main reaction chamber from 1060° C. to 900° C. in step S1, the theoretical doping concentration of the generated P-type doped silicon nanowires is 9*10 21 atm / cm 3 Except for the above, other conditions are exactly the same as those in Example 1.

[0103] Example 6

[0104] This embodiment provides a method for preparing P-type doped silicon nanowires, the method comprising the following steps:

[0105] S1 uses a quartz tube furnace as the main reaction chamber, raises the temperature of the main reaction chamber to 1000°C at a heating rate of 5°C / min, and maintains the temperature stable;

[0106] At the same time, the temperature of the aluminum chloride vaporization chamber is set to 200° C., aluminum chloride is vaporized into aluminum chloride vapor, and argon gas is used as a carrier gas at a flow rate of 300 sccm to carry the aluminum chloride vapor into the aluminum chloride generation chamber, so that it reacts with the metal aluminum carried in the quartz boat set in the aluminum chloride generation chamber to generate aluminum chloride gas, and release it into the inner cavity of the main reaction chamber;

[0107] At the same time, silicon tetrachloride is used as a silicon source and titanium tetrachloride is used as a catalyst source, mixed at a molar ratio of 40:1 and placed in a reaction material mixing vaporization chamber, the reaction material mixing vaporization chamber is set to a constant temperature of 40° C., and argon is used as a carrier gas at a flow rate of 300 sccm to load a mixed liquid of silicon tetrachloride and titanium tetrachloride into the inner cavity of the main reaction chamber;

[0108] At the same time, diborane (B2H6) was used as a doping source, and argon was used as a carrier gas to control the molar ratio of the two to be 1:25. The loaded diborane was introduced into the inner cavity of the main reaction chamber at a flow rate of 30 sccm.

[0109] When aluminum chloride, silicon source, catalyst source and doping source are mixed in the inner cavity of the main reactor, the reaction is carried out for 100 minutes to generate P-type doped silicon nanowires with a theoretical doping concentration of 1*10 19 atm / cm 3 .

[0110] Example 7

[0111] This embodiment provides a method for preparing P-type doped silicon nanowires. In addition to adjusting the temperature of the main reaction chamber from 1060°C to 1150°C in step S1, the theoretical doping concentration of the generated P-type doped silicon nanowires is 2*10 20 atm / cm 3 Except for the above, other conditions are exactly the same as those in Example 1.

[0112] Example 8

[0113] This embodiment provides a method for preparing P-type doped silicon nanowires. In step S1, the flow rate of aluminum chloride vapor carried by argon is adjusted from 180 sccm to 50 sccm, the carrier gas carrying silicon source and catalyst source is adjusted from 160 sccm to 100 sccm, and the ratio of doping source to carrier gas is adjusted from 1:25 to 1:15. The theoretical doping concentration of the generated P-type doped silicon nanowires is 3*10 21 atm / cm 3 Except for the above, other conditions are exactly the same as those in Example 1.

[0114] Example 9

[0115] The present embodiment provides a method for preparing P-type doped silicon nanowires. In the preparation method, in addition to adjusting the flow rate of aluminum chloride vapor loaded by argon from 180 sccm to 300 sccm in step S1, adjusting the carrier gas loaded with silicon source and catalyst source from 160 sccm to 200 sccm, adjusting the ratio of doping source to carrier gas from 1:25 to 1:2, and adjusting the reaction time in step S2 from 150 min to 30 min, the theoretical doping concentration of the generated P-type doped silicon nanowires is 2*10 22 atm / cm 3 Except for the above, other conditions are exactly the same as those in Example 1.

[0116] Example 10

[0117] This embodiment provides a method for preparing P-type doped silicon nanowires. In step S1, the molar ratio of diborane to argon is adjusted from 1:25 to 1:55, the vaporization temperature of the silicon source and catalyst source mixture is adjusted from 40°C to 45°C, and the carrier gas flow rate of the silicon source and catalyst source is adjusted from 300sccm to 250sccm. The theoretical doping concentration of the generated P-type doped silicon nanowires is 4*10 18 atm / cm 3 , except for the above, other conditions are exactly the same as those in Example 6.

[0118] Embodiment 11

[0119] This embodiment provides a method for preparing P-type doped silicon nanowires. In step S1, the molar ratio of diborane to argon is adjusted from 1:25 to 1:250, the vaporization temperature of the silicon source and catalytic source mixture is adjusted from 40°C to 45°C, and the carrier gas flow rate is adjusted from 300 sccm to 50 sccm. The theoretical doping concentration of the generated P-type doped silicon nanowires is 1*10 18 atm / cm 3 , except for the above, other conditions are exactly the same as those in Example 6.

[0120] Example 12

[0121] This embodiment provides a method for preparing P-type doped silicon nanowires. In the preparation method, in addition to adjusting the molar ratio of diborane to argon from 1:25 to 1:500 in step S1, the theoretical doping concentration of the generated P-type doped silicon nanowires is 5*10 17 atm / cm 3 , except for the above, other conditions are exactly the same as those in Example 6.

[0122] Comparative Example 1

[0123] This comparative example provides a method for preparing intrinsic silicon nanowires. Figure 1 The preparation device shown in the figure is used as a basis, but the doping source inlet tube 7 is not provided; that is, the preparation method does not use a doping source, and the other conditions are exactly the same as those in Example 1. The preparation method comprises the following steps:

[0124] S1 uses a quartz tube furnace as the main reaction chamber, raises the temperature of the main reaction chamber to 1060°C at a heating rate of 5°C / min, and maintains the temperature stable;

[0125] At the same time, the temperature of the aluminum chloride vaporization chamber is set to 180° C., aluminum chloride is vaporized into aluminum chloride vapor, and argon gas is used as a carrier gas at a flow rate of 180 sccm to carry the aluminum chloride vapor into the aluminum chloride generation chamber, so that it reacts with the metal aluminum carried in the quartz boat set in the aluminum chloride generation chamber to generate aluminum chloride gas, and release it into the inner cavity of the main reaction chamber;

[0126] At the same time, silicon tetrachloride was used as a silicon source and titanium tetrachloride was used as a catalyst source, mixed at a molar ratio of 30:1 and placed in a reaction material mixing vaporization chamber, the reaction material mixing vaporization chamber was set to a constant temperature of 28° C., and argon was used as a carrier gas at a flow rate of 160 sccm to carry a mixed liquid of silicon tetrachloride and titanium tetrachloride into the inner cavity of the main reaction chamber;

[0127] S2 When aluminum chloride, silicon source and catalyst source are mixed in the inner cavity of the main reactor, the reaction is carried out for 150 minutes to generate intrinsic silicon nanowires.

[0128] Comparative Example 2

[0129] This comparative example provides a method for preparing P-type doped silicon nanowires. Figure 1 The preparation device shown is based on the above, but the aluminum chloride generating chamber 2, the aluminum chloride vaporizing chamber 3 and the aluminum container 4 are not provided; that is, the preparation method does not use aluminum chloride or aluminum chloride vapor, and the preparation method comprises the following steps:

[0130] S1: A quartz tube furnace is used as the main reaction chamber, 2.0 g of the intrinsic silicon nanowires prepared in Comparative Example 1 are laid flat in the center of the inner cavity of the main reaction chamber, and the temperature of the main reaction chamber is raised to 1060° C. at a heating rate of 5° C. / min, and the temperature is maintained stable;

[0131] The reaction material mixing vaporization chamber does not contain a silicon source and a catalyst source, and is only used to pass argon as a carrier gas into the inner cavity of the main reaction chamber at a flow rate of 160 sccm;

[0132] At the same time, diborane (B2H6) was used as a doping source, and argon was used as a carrier gas to control the molar ratio of the two to be 1:25. The loaded diborane was introduced into the inner cavity of the main reaction chamber at a flow rate of 60 sccm.

[0133] When the doping source and the intrinsic silicon nanowires are mixed in the inner cavity of the main reactor, the reaction is carried out for 150 minutes to generate P-type doped silicon nanowires with a theoretical doping concentration of 1*10 21 atm / cm 3 .

[0134] Comparative Example 3

[0135] This comparative example provides a method for preparing P-type doped silicon nanowires. Figure 1 The preparation device shown is based on the above, but the doping source inlet pipe 7, the aluminum container 4 and the aluminum chloride generating chamber 2 are not provided, and the aluminum chloride vaporization chamber 3 is changed into a boric acid vaporization chamber for introducing boric acid vapor into the inner cavity of the main reaction chamber 1; that is, the preparation method does not use aluminum chloride or aluminum chloride vapor, and uses boric acid as a doping source, and the preparation method comprises the following steps:

[0136] S1: A quartz tube furnace is used as the main reaction chamber, 2.0 g of the intrinsic silicon nanowires prepared in Comparative Example 1 are spread flat in the center of the inner cavity of the main reaction chamber, and 50 g of boric acid is added into the boric acid vaporization chamber as a doping source;

[0137] The reaction material mixing vaporization chamber does not contain a silicon source and a catalyst source, and is only used to pass argon as a carrier gas into the inner cavity of the main reaction chamber at a flow rate of 160 sccm;

[0138] The temperature of the boric acid vaporization chamber was raised to 280°C (slightly lower than the boiling point of boric acid, 300°C) at a heating rate of 5°C / min, and argon was used as a carrier gas to carry boric acid vapor into the inner cavity of the main reaction chamber at a flow rate of 180 sccm. The temperature was maintained for 20 minutes to deposit a layer of boron oxide on the surface of the silicon nanowires;

[0139] The temperature of the main reaction chamber was raised to 1060°C at a heating rate of 5°C / min and the temperature was maintained stable;

[0140] S2 was subjected to high temperature propulsion reaction for 150 min to generate P-type doped silicon nanowires, with a theoretical doping concentration of 1*10 21 atm / cm 3 ;

[0141] After S3 doping was completed, the borosilicate glass on the surface of the P-type doped silicon nanowires was removed by washing with hydrofluoric acid, rinsed with deionized water, and finally dried at 180° C. for 3 hours in a nitrogen atmosphere.

[0142] The silicon nanowires obtained in the examples and comparative examples were subjected to ICP testing, and the actual doping concentration (mass percentage content, wt %) of doping elements such as boron or phosphorus in the silicon nanowires was measured based on the emission spectrum of the doping elements. The results are listed in Table 1.

[0143] Table 1

[0144]

[0145] As can be seen from the above, the preparation method disclosed in the present invention can produce doped silicon nanowires by in-situ doping, which can control the doping concentration in a wide range and evenly distribute the doping elements. The in-situ doping method is easier to achieve doping than the high-temperature diffusion method.

[0146] In comparison, the silicon nanowires produced in Comparative Example 1 without introducing the doping source gas are intrinsic silicon nanowires; Comparative Example 2 uses diborane as the doping source, and thermally decomposes diborane at the process temperature to generate boron atoms, and dopes the intrinsic silicon nanowires produced in Comparative Example 1 by means of high-temperature diffusion, thereby obtaining boron-doped silicon nanowires; Comparative Example 3 uses boric acid as the doping source to dope the intrinsic silicon nanowires produced in Comparative Example 1. The process includes vaporizing the doping source boric acid, depositing a layer of boron oxide on the surface of the intrinsic silicon nanowire, and undergoing a substitution reaction at the process temperature to generate boron atoms, which then diffuse into the silicon nanowire for doping. It can be seen that Comparative Examples 2 and 3 both belong to the doping of silicon nanowires by conventional high-temperature diffusion, and the actual doping concentration is limited by the diffusion law and presents a semi-Gaussian distribution (i.e., the concentration decreases with depth), resulting in a doping concentration much lower than in-situ doping. In addition, when diborane is used as a doping source, it is difficult to form a high-concentration doping source on the surface of silicon nanowires, and the utilization rate is extremely low; when boric acid is used as a doping source, although boric acid can form a layer of high-concentration boron oxide on the surface of silicon nanowires as a doping source, the uniformity of boron oxide deposited on the silicon nanowires is very poor, and it is not easy to uniformly dope. Furthermore, the doping process of boron oxide is at the expense of the oxidation of silicon nanowires. The substitution reaction in the diffusion process is extremely serious for the oxidation of silicon nanowires. The borosilicate glass generated by oxidation is washed away, and the silicon nanowire sample is seriously lost, resulting in large measurement errors.

[0147] Although in-situ doping can accurately control the doping concentration over a large range by adjusting the raw material ratio of the silicon source and the doping source. However, it is not difficult to see from Table 1 that the mass percentage concentration measured by ICP deviates from the theoretical doping amount (preset atomic concentration), especially when the doping concentration is high. The impact is more serious. This shows that in addition to the raw material ratio, there are some other minor factors that affect the final doping concentration. The reason is that due to the influence of the growth mechanism of silicon nanowires, the growth process of silicon nanowires is not direct crystallization, but crystallization through metal catalysts (alloy droplets). Therefore, the solubility of the doping element in the metal catalyst and the crystallization rate will have a certain influence on the final doping concentration. In addition, it can be seen from Example 4 that the choice of reaction temperature is very important. At a reaction temperature of 850°C, the saturated vapor pressure of aluminum is less than 1*10 -8atm, too low aluminum vapor concentration seriously affects the conversion of aluminum trichloride into aluminum monochloride, which in turn affects the conversion of silicon source and catalyst source and the generation of silicon nanowires.

[0148] The present invention illustrates the detailed structural features of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned detailed structural features, that is, it does not mean that the present invention must rely on the above-mentioned detailed structural features to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of the components selected by the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention. The preferred embodiments of the present invention are described in detail above, but the present invention is not limited to the specific details in the above-mentioned embodiments. Within the scope of the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0149] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0150] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A preparation device for doped silicon nanowires, characterized in that: The invention comprises a main reaction chamber (1), wherein an aluminum chloride generating chamber (2) is arranged in the main reaction chamber (1), the inner cavity of the aluminum chloride generating chamber (2) is connected to the inner cavity of the main reaction chamber (1), and releases aluminum chloride into the inner cavity of the main reaction chamber (1); the main reaction chamber (1) is also provided with a raw material inlet, and the raw material inlet is used to provide a silicon source, a catalytic source and a doping source into the inner cavity of the main reaction chamber (1).

2. The preparation device according to claim 1, characterized in that: The aluminum chloride generation chamber (2) is provided with an aluminum trichloride vapor inlet, an aluminum container (4) is provided in the inner cavity of the aluminum chloride generation chamber (2), and the aluminum chloride generation chamber (2) is provided with an aluminum chloride outlet for communicating with the inner cavity of the main reaction chamber (1) and releasing aluminum chloride; Preferably, the aluminum chloride vapor inlet is connected to the aluminum chloride vaporization chamber (3); Preferably, the aluminum container (4) comprises a quartz boat filled with metallic aluminum; Preferably, the main reaction chamber (1) comprises a quartz tube furnace; Preferably, the raw material inlet includes an independently arranged reaction material inlet and a doping source inlet, and the reaction material inlet is used to provide a mixture of a silicon source and a catalytic source into the inner cavity of the main reaction; Preferably, the reaction material inlet is provided with a reaction material inlet pipe (5) for introducing the silicon source and the catalyst source together, and extends into the inner cavity of the main reaction chamber (1); Preferably, one end of the reaction material inlet pipe (5) away from the inner cavity of the main reaction chamber (1) is connected to a reaction material mixing vaporization chamber (6) for the silicon source and the catalytic source; Preferably, the doping source inlet is provided with a doping source inlet tube (7) extending into the inner cavity of the main reaction chamber (1); Preferably, the main reaction chamber (1) is also provided with an exhaust gas outlet (8).

3. A method for preparing doped silicon nanowires, characterized in that: Using the preparation device according to claim 1 or 2, the method comprises: Aluminum monochloride is released into the inner cavity of the main reaction chamber (1) through the aluminum monochloride generation chamber (2), and at the same time, a silicon source, a catalytic source and a doping source are provided into the inner cavity of the main reaction chamber (1) through a raw material inlet, so that the aluminum monochloride, the silicon source, the catalytic source and the doping source are mixed in the inner cavity of the main reaction chamber and react to generate doped silicon nanowires.

4. The preparation method according to claim 3, characterized in that: The method for preparing the aluminum monochloride comprises: in an aluminum monochloride reaction chamber, allowing aluminum trichloride vapor to react with aluminum metal to generate aluminum monochloride gas; Preferably, the aluminum chloride vapor is generated in the aluminum chloride vaporization chamber (3) and introduced into the aluminum chloride generation chamber (2) via a carrier gas; Preferably, the flow rate of the carrier gas loaded with aluminum chloride vapor is 50 to 300 sccm; Preferably, the generation temperature of the aluminum chloride vapor is 160-200°C.

5. The preparation method according to claim 3 or 4, characterized in that: The silicon source includes silicon tetrachloride; Preferably, the catalytic source comprises a metal halide; Preferably, the metal halide comprises any one or a combination of at least two of titanium chloride, silver chloride, cupric chloride, cuprous chloride, ferric chloride, ferrous chloride, gold chloride, zinc chloride or lead chloride, preferably titanium chloride; Preferably, the molar ratio of the silicon source to the catalyst source is (10-50):1; Preferably, the silicon source and the catalyst source are mixed in the reaction material mixing and vaporizing chamber (6) and maintained at a constant temperature of 18 to 50° C.; Preferably, the silicon source and the catalyst source are introduced into the inner cavity of the main reaction chamber (1) through a reaction material inlet pipe (5) arranged at the reaction material inlet from a reaction material mixing vaporization chamber (6) through a carrier gas; Preferably, the flow rate of the carrier gas loaded with the silicon source and / or the catalyst source is 20 to 300 sccm.

6. The preparation method according to any one of claims 3 to 5, characterized in that: The doping source includes a P-type doping source or an N-type doping source; Preferably, the P-type doping source includes borane, boron powder, or any one or a combination of at least two of aluminum, gallium or indium metal elements; Preferably, the N-type doping source includes any one or a combination of at least two of phosphine, phosphorus powder, elemental arsenic, or elemental antimony or bismuth metals; Preferably, the doping source is a gaseous substance; Preferably, the doping source is introduced into the inner cavity of the main reaction chamber (1) through a doping source inlet pipe (7) arranged on the doping source inlet by means of a carrier gas; Preferably, the flow rate of the carrier gas carrying the doping source is 20 to 100 sccm; Preferably, the molar ratio of the doping source to the carrier gas is 1:(1-500); Preferably, the concentration of the doping element in the doped silicon nanowire is 1*10 17 ~1*10 22 atm / cm 3 .

7. The preparation method according to any one of claims 3 to 6, characterized in that: The insulation temperature of the reaction is 900-1100°C; Preferably, the heating rate of the reaction is 3-7°C / min; Preferably, the reaction time is 30 to 300 minutes.

8. The preparation method according to any one of claims 3 to 7, characterized in that: The method comprises the following steps: S1 uses a quartz tube furnace as the main reaction chamber (1), raises the temperature of the main reaction chamber (1) to 900-1100° C. at a heating rate of 3-7° C. / min, and maintains the temperature stable; At the same time, the temperature of the aluminum chloride vaporization chamber (3) is set to 160-200° C., aluminum chloride is vaporized into aluminum chloride vapor, and argon gas is used as a carrier gas to carry the aluminum chloride vapor and pass it into the aluminum chloride generation chamber (2) at a flow rate of 50-300 sccm, so that the aluminum chloride vapor is mixed with aluminum vapor generated by metal aluminum carried in a quartz boat arranged in the aluminum chloride generation chamber (2) to react, thereby generating aluminum chloride gas, which is released into the inner cavity of the main reaction chamber (1); At the same time, silicon tetrachloride is used as a silicon source and titanium tetrachloride is used as a catalyst source, mixed in a molar ratio of (10-50):1 and placed in a reaction material mixing vaporization chamber (6), the reaction material mixing vaporization chamber (6) is set to a constant temperature of 18-50° C., and argon is used as a carrier gas at a flow rate of 20-300 sccm to pass the mixed liquid loaded with silicon tetrachloride and titanium tetrachloride into the inner cavity of the main reaction chamber (1); At the same time, diborane is used as a doping source, argon is used as a carrier gas, and the molar ratio of the two is controlled to be 1:(1-500), and the loaded diborane is introduced into the inner cavity of the main reaction chamber (1) at a flow rate of 20-100 sccm; S2 When aluminum chloride, silicon source, catalyst source and doping source are mixed in the inner cavity of the main reactor, the reaction is carried out for 30 to 300 minutes, and the concentration of the doping element generated is 1*10 17 ~1*10 22 atm / cm 3 doped silicon nanowires.

9. A doped silicon nanowire, characterized in that: Obtained according to the preparation method according to any one of claims 3 to 8.

10. An application of the doped silicon nanowire according to claim 9, characterized in that: The applications include sensors, field effect transistors, photocatalysis, lithium-ion batteries or photovoltaic cells.

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