CN108963030A - The preparation method of silicon-based nano structure photovoltaic material - Google Patents

Abstract

The invention discloses a method for preparing silicon-based nanostructure photovoltaic materials, which relates to the technical field of photovoltaic materials. It includes the following steps: cut silicon wafers of a certain size according to actual needs, polish the cut parts of the silicon wafers, put them into the pre-prepared solution for 3H‑4.5H after polishing, and stir once every 20Min during the soaking period Take out the soaked silicon wafer and place it in a high-temperature furnace to remove impurities. The temperature adjustment range in the furnace is 650-750 degrees Celsius, and the duration is 0.3H-0.5H, and then it is cooled to normal temperature with an inert gas; The back of the silicon wafer is chemically deposited. After adopting the above-mentioned technical scheme, the beneficial effects of the present invention are: convenient process, high use value, simple raw materials, low production cost, which is conducive to large-scale production, and can effectively prepare silicon-based nanostructure photovoltaic materials with good optical properties. And electrical properties, with good contact electrical properties, can improve the transport capacity of carriers, and can realize the conversion efficiency of photovoltaic materials.

Description

Preparation method of silicon-based nanostructure photovoltaic material

technical field

The invention relates to the technical field of photovoltaic materials, in particular to a preparation method of silicon-based nanostructure photovoltaic materials.

Background technique

With the rapid development of science and technology and the increasing awareness of environmental protection, the new energy industry has a strong momentum of development. As an intermittent new energy source, solar energy requires high-performance photovoltaic materials for storage.

Photovoltaic materials are also called solar cell materials. The materials that can be used as solar cell materials include monocrystalline silicon, polycrystalline silicon, amorphous silicon, GaAs, GaAlAs, InP, CdS, CdTe, etc.

Nano-silicon refers to crystalline silicon particles with a diameter of less than 5 nanometers (one billion (1G) of a meter). Nano-silica powder has the characteristics of high purity, small particle size, and uniform distribution. It has the characteristics of large surface area, high surface activity and low bulk density. The product is non-toxic and tasteless. Nano-silicon powder is a new generation of photoelectric semiconductor material, which has a wide gap energy semiconductor and is also a high-power light source material.

Dozens of silicon/silicon oxide nanostructures have been designed on silicon substrates to achieve photoluminescence in major wavelength bands from near-ultraviolet to near-infrared (including 1.54 and 1.62 μm) and low forward or reverse bias Threshold voltage electroluminescence, and proposed widely supported photoluminescence and electroluminescence models, which laid a certain foundation for the ultimate realization of silicon-based optoelectronic integration. It has important scientific significance and great application prospect.

The current preparation process of silicon-based nanostructured photovoltaic materials is cumbersome, the use value is not high, the raw materials are complicated, and the production cost is huge, which is not conducive to large-scale production. It cannot effectively prepare standard silicon-based nanostructured photovoltaic materials, and does not have good optical and electrical properties. properties, do not have good contact electrical properties, cannot improve the transport capacity of carriers, and are difficult to achieve conversion efficiency of photovoltaic materials.

Contents of the invention

The object of the present invention is to aim at the defects and deficiencies of the prior art, and to provide a method for preparing silicon-based nanostructured photovoltaic materials, which has convenient process, high use value, simple raw materials, low production cost, is conducive to large-scale production, and can effectively prepare The standard silicon-based nanostructure photovoltaic material has good optical and electrical properties, has good contact electrical properties, can improve the transport capacity of carriers, and can realize the conversion efficiency of photovoltaic materials.

To achieve the above object, the present invention adopts the following technical scheme, which comprises the steps:

Step 1. Cut silicon wafers of certain specifications according to actual needs, and polish the cut parts of the silicon wafers. After polishing, put them into the pre-prepared solution and soak for 3H-4.5H. During the soaking period, stir once every 20Min;

Step 2. Take out the soaked silicon wafer and place it in a high-temperature furnace to remove impurities. The temperature adjustment range in the furnace is 650°C-750°C, and the duration is 0.3H-0.5H. Then cool it to room temperature with an inert gas ;

Step 3, deposit a layer of silicon oxide film on the back of the silicon wafer by chemical precipitation method, the thickness of the silicon oxide film is 100nm-300nm;

Step 4, coating a layer of metal thin film layer on the front side of the silicon wafer, the thickness of the metal thin film layer is 200nm-400mm;

Step 5, treating the four sides of the front surface of the silicon wafer with a strong etchant to remove the surface damage caused by step 4;

Step 6. Etching the metal thin film layer with an ion beam to etch out the required electrode pattern, and the etching depth is 150nm to 170mm;

Step 7. Place the silicon wafer in an alkaline solution and boil it at a temperature of 120°C-200°C for 2H-3.5H to remove the damage caused by step 6;

Step 8, drying the boiled silicon wafer with inert gas again;

Step 9: Follow the electrode pattern, pour metal liquid into it, and rapidly refrigerate, the refrigeration temperature is -30 degrees Celsius - 50 degrees Celsius, and complete the preparation of silicon-based nanostructure photovoltaic materials.

The specifications of the silicon wafers in the first step are 5 cm x 5 cm x 2 cm, 10 cm x 10 cm x 2 cm, and 15 cm x 15 cm x 2 cm.

The solution in the step 1 is a mixture of peracetic acid and hydrogen peroxide, the molar concentration range of peracetic acid is 3-15%, and the molar concentration range of hydrogen peroxide is 15-20%.

The inert gas in the step two and step eight is helium, neon, argon, krypton, xenon.

The strong corrosive agent in the described step 5 is potassium dichromate, chlorate, potassium permanganate, fuming sulfuric acid.

The alkaline solution in the step seven is alkaline water.

The working principle of the present invention: cut silicon wafers of certain specifications according to actual needs, and polish the cut parts of the silicon wafers. After polishing, put them into the pre-prepared solution and soak for 3H-4.5H, and stir every 20Min during the soaking period. Once; take out the soaked silicon wafer and place it in a high-temperature furnace to remove impurities. The temperature adjustment range in the furnace is 650°C-750°C, and the duration is 0.3H-0.5H, and then it is cooled to room temperature with an inert gas; Precipitate a layer of silicon oxide film on the back of the silicon wafer by chemical precipitation method, the thickness of the silicon oxide film is 100nm-300nm; coat a layer of metal film on the front of the silicon wafer, the thickness of the metal film layer is 200nm-400mm; Treat the surrounding area of the front surface of the silicon wafer with a strong etchant to remove the surface damage caused by step 4; etch the metal film layer with an ion beam to etch out the required electrode pattern with an etching depth of 150nm to 170mm; place the silicon wafer in an alkaline Boiling in the solution, the boiling temperature is 120°C-200°C, and the boiling time is 2H-3.5H, which is used to remove the damage caused in step 6; dry the boiled silicon wafer with inert gas again; follow the electrode pattern , pour metal liquid into it, and rapidly refrigerate, and the refrigeration temperature is -30 degrees Celsius to 50 degrees Celsius to complete the preparation of silicon-based nanostructure photovoltaic materials.

After adopting the above technical scheme, the beneficial effects of the present invention are: convenient process, high use value, simple raw materials, low production cost, which is conducive to large-scale production, and can effectively prepare silicon-based nanostructure photovoltaic materials with good optical properties. And electrical properties, with good contact electrical properties, can improve the transport capacity of carriers, and can realize the conversion efficiency of photovoltaic materials.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only These are some embodiments of the present invention. For those skilled in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is a schematic block diagram of the process of the present invention.

Detailed ways

Referring to shown in Fig. 1, the technical scheme that this specific embodiment adopts, it comprises the following steps:

Step 1. Cut silicon wafers of a certain specification according to actual needs, and polish the cut parts of the silicon wafers. After polishing, put them into the pre-prepared solution and soak for 3H-4.5H. During the soaking period, stir once every 20Min; Strict cleaning is required in the production of chips, and trace pollution will also cause device failure. The purpose of cleaning is to remove surface contamination impurities, including organic and inorganic substances. Some of these impurities exist in the atomic state or ion state, and some exist in the form of thin films or particles on the surface of the silicon wafer. Organic contamination includes photoresists, organic solvent residues, synthetic waxes, and grease or fibers from human contact with devices, tools, and utensils. Inorganic pollution includes heavy metals such as gold, copper, iron, chromium, etc., which seriously affect the lifetime of minority carriers and surface conductance; alkali metals such as sodium, etc., cause serious leakage; particle pollution includes silicon slag, dust, bacteria, microorganisms, organic colloidal fibers, etc. , will lead to various defects;

Step 2. Take out the soaked silicon wafer and place it in a high-temperature furnace to remove impurities. The temperature adjustment range in the furnace is 650°C-750°C, and the duration is 0.3H-0.5H. Then cool it to room temperature with an inert gas ;

Step 3, deposit a layer of silicon oxide film on the back of the silicon wafer by chemical precipitation method, the thickness of the silicon oxide film is 100nm-300nm;

Step 4, coating a layer of metal thin film layer on the front side of the silicon wafer, the thickness of the metal thin film layer is 200nm-400mm;

Step 5, treating the four sides of the front surface of the silicon wafer with a strong etchant to remove the surface damage caused by step 4;

Step 6: Etch the metal thin film layer with ion beams to etch out the required electrode patterns, and the etching depth is 150nm-170mm; ion beam etching refers to the transfer of energy from incident ions to solid targets when directional high-energy ions hit the solid target On the solid surface atoms, if the binding energy between the solid surface atoms is lower than the incident ion energy, the solid surface atoms will be moved or removed from the surface. Usually, the ions used in ion beam etching come from inert gases; the minimum diameter of the ion beam is about 10nm, and the minimum structure etched by the ion beam may not be smaller than 10nm. At present, the beam spot of focused ion beam etching can reach below 100nm, and the minimum can reach 10nm, and the processing result with the minimum line width of 12nm can be obtained. Compared with the interaction between electrons and solids, the scattering effect of ions in solids is small, and can be etched less than 50nm at a faster direct writing speed, so focused ion beam etching is an ideal method for nanofabrication; in addition Another advantage of focused ion beam technology is that it can directly manufacture various nano-device structures under computer control without mask implantation, or even without development and etching;

Step 7. Place the silicon wafer in an alkaline solution and boil it at a temperature of 120°C-200°C for 2H-3.5H to remove the damage caused by step 6;

Step 8, drying the boiled silicon wafer with inert gas again;

Step 9: Follow the electrode pattern, pour metal liquid into it, and rapidly refrigerate, the refrigeration temperature is -30 degrees Celsius - 50 degrees Celsius, and complete the preparation of silicon-based nanostructure photovoltaic materials.

The specifications of the silicon wafers in the first step are 5 cm x 5 cm x 2 cm, 10 cm x 10 cm x 2 cm, and 15 cm x 15 cm x 2 cm.

The solution in the step 1 is a mixture of peracetic acid and hydrogen peroxide, the molar concentration range of peracetic acid is 3-15%, and the molar concentration range of hydrogen peroxide is 15-20%. Peracetic acid is a strong oxidant that can kill all microorganisms, including viruses, bacteria, fungi and spores, and can be widely used in disinfection of various utensils and environments; hydrogen peroxide can have oxidation or reduction effects in different situations , available oxidants, bleaches, disinfectants, dechlorination agents, and for rocket fuel, organic or inorganic peroxides, foam and other porous substances.

The inert gas in the step two and step eight is helium, neon, argon, krypton, xenon. Taking advantage of the extremely inactive chemical properties of inert gases, they are often used as protective gases in the production of silicon in the semiconductor industry.

The strong corrosive agent in the described step 5 is potassium dichromate, chlorate, potassium permanganate, fuming sulfuric acid. Potassium dichromate is a strong oxidant, which is widely used in laboratories and industries; it is used to make chrome alum, matches, chrome pigments, and for tanning, electroplating, organic synthesis, etc.; chlorate has a strong oxidizing effect , release oxygen after heating, and release heat at the same time; after mixing with combustibles, such as sulfur, carbon, phosphorus, there will be a violent explosion when it hits; it cannot be piled together with reducing agents or combustible substances, and is generally soluble in water. However, the solubility of potassium chlorate is small; potassium permanganate is soluble in water and lye, slightly soluble in methanol, acetone and sulfuric acid. It is widely used as an oxidant in chemical production, and as a water treatment agent in water purification and wastewater treatment. Odor and decolorization can be controlled by oxidizing hydrogen sulfide, phenol, iron, manganese, organic and inorganic pollutants; in gas purification, trace sulfur, arsenic, phosphorus, silane, borane and sulfide can be removed; In mining and metallurgy, it is used to separate molybdenum from copper, remove impurities from zinc and cadmium, and be an oxidant for compound flotation; it is also used as a bleaching agent for special fabrics, waxes, greases and resins, an adsorbent for gas masks, and wood And copper coloring agent, etc.; when fuming sulfuric acid is mixed with water, sulfur trioxide is combined with water to form sulfuric acid; relative density is about 1.9 (containing 20% sulfur trioxide); strongly corrosive.

The alkaline solution in the step seven is alkaline water. Alkaline water is a natural alkali, the main components are sodium carbonate and potassium carbonate; it is a highly corrosive alkaline chemical, the appropriate alkali can make the powder absorb water when it is decomposed by heat, and achieve good viscosity. Elasticity; Alkaline water also has functions such as antiseptic effect and neutralizing acidity.

The working principle of the present invention: cut silicon wafers of certain specifications according to actual needs, and polish the cut parts of the silicon wafers. After polishing, put them into the pre-prepared solution and soak for 3H-4.5H, and stir every 20Min during the soaking period. Once; take out the soaked silicon wafer and place it in a high-temperature furnace to remove impurities. The temperature adjustment range in the furnace is 650°C-750°C, and the duration is 0.3H-0.5H, and then it is cooled to room temperature with an inert gas; Precipitate a layer of silicon oxide film on the back of the silicon wafer by chemical precipitation method, the thickness of the silicon oxide film is 100nm-300nm; coat a layer of metal film on the front of the silicon wafer, the thickness of the metal film layer is 200nm-400mm; Treat the surrounding area of the front surface of the silicon wafer with a strong etchant to remove the surface damage caused by step 4; etch the metal film layer with an ion beam to etch out the required electrode pattern with an etching depth of 150nm to 170mm; place the silicon wafer in an alkaline Boiling in the solution, the boiling temperature is 120°C-200°C, and the boiling time is 2H-3.5H, which is used to remove the damage caused in step 6; dry the boiled silicon wafer with inert gas again; follow the electrode pattern , pour metal liquid into it, and rapidly refrigerate, and the refrigeration temperature is -30 degrees Celsius to 50 degrees Celsius to complete the preparation of silicon-based nanostructure photovoltaic materials.

After adopting the above technical scheme, the beneficial effects of the present invention are: convenient process, high use value, simple raw materials, low production cost, which is conducive to large-scale production, and can effectively prepare silicon-based nanostructure photovoltaic materials with good optical properties. And electrical properties, with good contact electrical properties, can improve the transport capacity of carriers, and can realize the conversion efficiency of photovoltaic materials.

The above is only used to illustrate the technical solution of the present invention and not to limit it. Other modifications or equivalent replacements made by those skilled in the art to the technical solution of the present invention should be considered as long as they do not depart from the spirit and scope of the technical solution of the present invention. fall within the scope of the claims of the present invention.

Claims (6)

1. The preparation method of silicon-based nanostructure photovoltaic material is characterized in that it comprises the following steps: Step 1. Cut silicon wafers of certain specifications according to actual needs, and polish the cut parts of the silicon wafers. After polishing, put them into the pre-prepared solution and soak for 3H-4.5H. During the soaking period, stir once every 20Min; Step 2. Take out the soaked silicon wafer and place it in a high-temperature furnace to remove impurities. The temperature adjustment range in the furnace is 650°C-750°C, and the duration is 0.3H-0.5H. Then cool it to room temperature with an inert gas ; Step 3, deposit a layer of silicon oxide film on the back of the silicon wafer by chemical precipitation method, the thickness of the silicon oxide film is 100nm-300nm; Step 4, coating a layer of metal thin film layer on the front side of the silicon wafer, the thickness of the metal thin film layer is 200nm-400mm; Step 5, treating the four sides of the front surface of the silicon wafer with a strong etchant to remove the surface damage caused by step 4; Step 6. Etching the metal thin film layer with an ion beam to etch out the required electrode pattern, and the etching depth is 150nm to 170mm; Step 7. Place the silicon wafer in an alkaline solution and boil it at a temperature of 120°C-200°C for 2H-3.5H to remove the damage caused by step 6; Step 8, drying the boiled silicon wafer with inert gas again; Step 9: Follow the electrode pattern, pour metal liquid into it, and rapidly refrigerate, the refrigeration temperature is -30 degrees Celsius - 50 degrees Celsius, and complete the preparation of silicon-based nanostructure photovoltaic materials. 2. The method for preparing silicon-based nanostructure photovoltaic materials according to claim 1, characterized in that: the specifications of the silicon wafer in the first step are 5 cm × 5 cm × 2 cm, 10 cm × 10 cm × 2 cm , 15 cm x 15 cm x 2 cm. 3. the preparation method of silicon-based nanostructure photovoltaic material according to claim 1, is characterized in that: the solution in described step 1 is the mixture of peracetic acid, hydrogen peroxide, and the molar concentration scope of peracetic acid is 3-15%, The molar concentration of hydrogen peroxide ranges from 15-20%. 4. The method for preparing silicon-based nanostructure photovoltaic materials according to claim 1, characterized in that: the inert gas in the step 2 and step 8 is helium, neon, argon, krypton, xenon. 5 . The method for preparing a silicon-based nanostructure photovoltaic material according to claim 1 , wherein the strong corrosive agent in step 5 is potassium dichromate, chlorate, potassium permanganate, and oleum. 6. the preparation method of silicon-based nanostructure photovoltaic material according to claim 1, is characterized in that: in described step 7, alkaline solution is alkaline water.