Preparation method of two-dimensional semiconductor phase platinum diselenide single crystal material

Abstract

The invention discloses a preparation method of a two-dimensional semiconductor phase platinum diselenide single-crystal material, relates to the technical field of nano material preparation, and is characterized in that the method is used for preparing a high-quality single-crystal two-dimensional semiconductor phase PtSe2 material based on a liquid-phase precursor assisted chemical vapor deposition (CVD) method. According to the method, the stoichiometric ratio of a platinum source to a selenium source is accurately regulated and controlled through a liquid-phase precursor, and the controllable preparation of the high-quality and large-size two-dimensional PtSe2 single crystal is realized by further optimizing a CVD (Chemical Vapor Deposition) preparation process. The method comprises the specific steps of liquid phase precursor preparation, substrate surface pretreatment, precursor fixation and nucleation, CVD-gas-solid reaction, cooling and collection. The method can solve the problems of high reaction temperature, difficulty in controlling stoichiometric ratio, many side reactions, limited substrate selection, low yield, poor repeatability, complex process and the like in the prior art, realizes controllable preparation of the high-quality and large-size PtSe2 single crystal material, and promotes application of the PtSe2 single crystal material in the fields of electronic devices, photoelectric detectors and catalysis.

Description

Technical Field

[0001] The invention relates to the technical field of nano material preparation, and more specifically, to a method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material. Background Art

[0002] Two-dimensional materials have attracted extensive attention in the field of nanotechnology due to their unique physical, chemical and electronic properties. Since the discovery of graphene, transition metal dichalcogenides (TMDCs) such as MoS 2 , WS 2 Platinum diselenide (PtSe 2 ) As an emerging TMDC material with a layered structure and adjustable band gap, it shows great application potential in semiconductor devices, photodetectors, sensors and catalysis.

[0003] PtS 2 The crystal structure of PtSe is formed by a layer of platinum atoms sandwiched between two layers of selenium atoms. The layers are bonded by van der Waals forces and can be peeled off into single or multi-layer two-dimensional materials. 2 With direct bandgap characteristics, multilayer PtSe 2 It behaves as an indirect bandgap semiconductor. This bandgap tunability makes it of great application value in optoelectronic devices. 2 It also has high carrier mobility, excellent light absorption properties and good chemical stability, and is considered to be an ideal material for the next generation of high-performance electronic and optoelectronic devices.

[0004] Although PtSe 2 Although it has excellent performance, the controllable preparation of high-quality single crystal materials still faces many challenges. 2 The main methods for materials include mechanical exfoliation, chemical vapor deposition (CVD) and liquid phase synthesis. However, these methods have the following problems in practical applications:

[0005] 1. High reaction temperature and high energy consumption

[0006] Existing CVD method for preparing PtSe 2 High temperatures (above 600°C) are usually required, which not only increases energy consumption but may also lead to more material defects and affect the crystallization quality.

[0007] 2. The stoichiometric ratio is difficult to control accurately

[0008] Existing methods mostly use solid platinum sources (such as platinum foil or platinum salt) and selenium powder as precursors. It is difficult to accurately control the stoichiometric ratio of the platinum source and the selenium source, resulting in uneven material composition and poor crystal quality.

[0009] 3. Many side reactions and low material purity

[0010] The liquid precursor (such as platinum salt solution) used in the liquid phase synthesis method is easy to decompose at high temperature to produce by-products, which affect the purity and crystallinity of the material.

[0011] 4. Limited substrate selection

[0012] Existing methods mostly rely on specific substrates (such as metal, mica or sapphire substrates), which limits the versatility of the material and the flexibility of subsequent device processing.

[0013] 5. Low yield, difficult to prepare on a large scale

[0014] Although mechanical exfoliation can obtain high-quality single-crystalline PtSe 2 , but the output is extremely low and cannot meet the needs of large-scale applications.

[0015] 6. Complex process and poor repeatability

[0016] Existing methods such as molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) have high equipment costs, complex processes, difficulty in large-scale preparation, and poor repeatability.

[0017] Therefore, it is necessary to develop a simple, efficient, and large-scale method for preparing high-quality single-crystalline two-dimensional semiconductor phase PtSe. 2 The approach to the material is of great importance. Summary of the invention

[0018] The purpose of the present invention is to provide a method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material, aiming to solve the problems of high reaction temperature, difficult to control stoichiometric ratio, many side reactions, limited substrate selection, low yield, and complex process in the prior art. The method uses a liquid phase precursor assisted CVD method to achieve high-quality, large-size PtSe 2 The controllable preparation of materials promotes their application in electronic devices, photodetectors and catalysis.

[0019] The above technical objectives of the present invention are achieved through the following technical solutions: A method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material, comprising the following steps:

[0020] S1. Liquid precursor preparation;

[0021] S2. Substrate surface pretreatment;

[0022] S3. Precursor coating;

[0023] S4.CVD-gas-solid reaction;

[0024] S5. Cooling and collection.

[0025] The present invention is further configured as follows: the specific operation of preparing the liquid precursor in S1 is as follows:

[0026] (1) Dissolving a platinum salt and a selenium source in a solvent to form a uniform liquid precursor solution; the solvent includes but is not limited to a hydrochloric acid solution with a concentration of 0.001-1M, a sodium hydroxide solution with a concentration of 0.001-1M, and deionized water; the platinum salt includes but is not limited to chloroplatinic acid, platinum chloride, and platinum sulfate.

[0027] (2) the molar ratio of the platinum salt to the selenium source is 2:1 to 1:4 to ensure precise control of the stoichiometric ratio;

[0028] (3) The solution is evenly mixed by stirring and ultrasonic treatment to avoid precipitation or stratification.

[0029] By adopting the above technical solution, the liquid phase precursor can accurately control the stoichiometric ratio of the platinum source and the selenium source to ensure the uniformity of the reaction. By spin coating or drop coating, a uniform precursor film can be formed on the substrate surface to provide high-quality single crystal PtSe 2 Provides a basis for growth.

[0030] The present invention is further configured as follows: the specific operations of the substrate pretreatment in S2 are as follows:

[0031] (1) Select high-purity silicon wafers, silicon dioxide substrates or flexible substrates;

[0032] (2) ultrasonic cleaning with acetone, isopropanol, and deionized water for 10 minutes in sequence to remove surface contaminants;

[0033] (3) Blow dry the substrate with nitrogen to ensure the surface is clean and dry.

[0034] By adopting the above technical solution and selecting a variety of substrates (such as silicon wafers, silicon dioxide substrates and flexible substrates), the versatility of materials and the flexibility of device processing are improved.

[0035] The present invention is further configured as follows: the specific operation of the precursor coating in S3 is as follows:

[0036] (1) Spin-coating the liquid precursor solution uniformly on the substrate surface;

[0037] (2) Control the thickness of the precursor film by spin coating or drop coating, with a spin coating speed of 2000-4000 rpm and a time of 30-60 seconds;

[0038] (3) After coating, pre-bake the substrate at 80-120°C for 5-10 minutes to remove the solvent.

[0039] By adopting the above technical solution, the reaction temperature is reduced to 400-550℃, reducing material defects and side reactions caused by high temperature. Low temperature reaction is conducive to the formation of high-quality single crystal PtSe 2 , while reducing energy consumption.

[0040] The present invention is further configured as follows: the specific operation of the CVD reaction in S4 is as follows:

[0041] (1) placing the substrate coated with the precursor in a CVD furnace and reacting under the protection of an inert gas;

[0042] (2) The reaction temperature is 400-550°C and the reaction time is 30-90 minutes;

[0043] (3) Selenium vapor is generated by evaporating selenium powder at 200-300°C and transported to the reaction zone by a carrier gas;

[0044] (4) By controlling the selenium powder evaporation temperature and carrier gas flow rate, the selenium vapor concentration is adjusted to ensure reaction uniformity.

[0045] By adopting the above technical solution, the selenium powder evaporation temperature and carrier gas flow rate are controlled to accurately adjust the selenium vapor concentration, thereby ensuring sufficient supply of selenium source during the reaction and avoiding selenium defects.

[0046] The present invention is further configured as follows: the specific operations of cooling and collecting in S5 are as follows:

[0047] (1) After the reaction is completed, turn off the heating system and allow the furnace to cool naturally to room temperature;

[0048] (2) Remove the substrate and obtain high-quality single-crystalline two-dimensional semiconductor phase PtSe 2 Material;

[0049] (3) The materials were characterized by optical microscopy, scanning electron microscopy (SEM), and Raman spectroscopy to ensure their crystalline quality and uniformity.

[0050] The present invention is further configured as follows: when preparing the liquid precursor, the concentration of the platinum salt is 0.01-0.1 mol / L, and the concentration of the selenium source is 0.02-0.4 mol / L.

[0051] The present invention is further configured as follows: the spin coating speed is preferably 3000 rpm, and the spin coating time is preferably 30 seconds.

[0052] The present invention is further configured as follows: the reaction temperature of the CVD reaction is preferably 500°C, the reaction time is preferably 60 minutes, and the selenium powder evaporation temperature is preferably 250°C.

[0053] The present invention is further configured as follows: the carrier gas flow rate in the CVD reaction is 50-100 sccm.

[0054] In summary, the present invention has the following beneficial effects:

[0055] 1. Low reaction temperature and low energy consumption

[0056] Existing technology: Traditional CVD method for preparing PtSe 2 Usually high temperatures (above 600°C) are required, which consumes a lot of energy and can easily lead to material defects.

[0057] The present invention reduces the reaction temperature to 400-550° C. by using a liquid precursor-assisted CVD method, significantly reduces energy consumption and material defects caused by high temperature, and improves crystal quality.

[0058] 2. The stoichiometric ratio is precisely controllable

[0059] Existing technology: Existing methods mostly use solid platinum sources (such as platinum foil or platinum salt) and selenium powder as precursors. It is difficult to accurately control the stoichiometric ratio of the platinum source and the selenium source, resulting in uneven material composition.

[0060] The present invention utilizes liquid precursors (such as chloroplatinic acid and sodium selenosulfate solution) to accurately control the stoichiometric ratio of a platinum source and a selenium source, thereby ensuring uniform material composition and improving crystal quality.

[0061] 3. Few side reactions and high material purity

[0062] Prior art: The liquid precursor used in the liquid phase synthesis method is easily decomposed at high temperatures to produce by-products, which affect the purity and crystallinity of the material.

[0063] The present invention reduces the occurrence of side reactions and improves the purity and crystallinity of materials by optimizing the composition and reaction conditions of liquid phase precursors.

[0064] 4. Flexible substrate selection and strong versatility

[0065] Existing technologies: Existing methods mostly rely on specific substrates (such as mica or sapphire), which limits the versatility of the material and the flexibility of subsequent device processing.

[0066] The present invention is applicable to a variety of substrates (such as silicon wafers, silicon dioxide substrates and flexible substrates), and improves the versatility of materials and the flexibility of device processing.

[0067] 5. Large area, uniform preparation, high yield

[0068] Existing technology: The output of mechanical stripping method is extremely low, and CVD method and liquid phase synthesis method are difficult to achieve large-area uniform preparation.

[0069] This invention: Using liquid precursor-assisted CVD method to achieve large-area, uniform single-crystal PtSe 2Thin film preparation, increasing production and meeting large-scale application needs.

[0070] 6. Simple process and good repeatability

[0071] Existing technologies: Existing methods such as molecular beam epitaxy (MBE) and pulsed laser deposition (PLD) have high equipment costs, complex processes, difficulty in large-scale preparation, and poor repeatability.

[0072] The invention has the advantages of simple process, easy control of parameters, good repeatability and suitability for industrial production.

[0073] 7. Material properties are adjustable and widely used

[0074] Existing technology: Existing methods are difficult to precisely control PtSe 2 The number of layers, lattice orientation and semiconductor properties limit its application in devices.

[0075] The present invention: by adjusting the precursor concentration and reaction conditions, the PtSe 2 The number of layers, lattice orientation and semiconductor performance can meet the application requirements of different devices.

[0076] 8. Environmentally friendly and low cost

[0077] Existing technologies: Some methods use toxic or expensive chemical reagents, which increases costs and environmental burdens.

[0078] The present invention adopts environmentally friendly liquid precursor and low-temperature CVD process, thereby reducing cost and environmental burden. BRIEF DESCRIPTION OF THE DRAWINGS

[0079] Figure 1 The CVD-grown semiconductor phase PtSe 2 Flow chart of preparation of single crystal materials;

[0080] Figure 2 is PtSe in Example 1 of the present invention 2 Optical microscope photos of samples;

[0081] Figure 3 It is the typical semiconductor phase PtSe in Example 1 of the present invention. 2 Raman spectra;

[0082] Figure 4 is a typical optical microscope photograph in Example 2 of the present invention;

[0083] Figure 5 It is the typical semiconductor phase PtSe in Example 2 of the present invention. 2 Raman spectrum. DETAILED DESCRIPTION

[0084] The following is combined with Figure 1-5 The present invention is described in further detail.

[0085] Example 1: A method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material

[0086] (1) Dissolve 0.05 mol / L chloroplatinic acid and 0.1 mol / L sodium selenosulfate in deionized water to form a liquid precursor solution.

[0087] (2) Take a silicon wafer and ultrasonically clean it with acetone, isopropanol and deionized water for 10 minutes in sequence, and blow dry it with nitrogen.

[0088] (3) The precursor solution was spin-coated on the surface of the silicon wafer at a speed of 3000 rpm for 30 seconds, followed by pre-baking at 100° C. for 5 minutes.

[0089] (4) Placing the silicon wafer coated with the precursor in a CVD furnace and reacting under argon protection at a reaction temperature of 500° C., a reaction time of 60 minutes, and a selenium powder evaporation temperature of 250° C.

[0090] (5) After the reaction is completed, the mixture is naturally cooled to room temperature to obtain high-quality single-crystalline two-dimensional semiconductor phase PtSe 2 Material.

[0091] Example 2: A method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material

[0092] (1) Dissolve 0.03 mol / L chloroplatinic acid and 0.06 mol / L sodium selenosulfate in deionized water to form a liquid precursor solution.

[0093] (2) Take a piece of silicon dioxide substrate, ultrasonically clean it with acetone, isopropanol and deionized water for 10 minutes in sequence, and blow dry it with nitrogen gas.

[0094] (3) The precursor solution was drop-coated on the surface of the silicon dioxide substrate and then pre-baked at 80°C for 10 minutes.

[0095] (4) Placing the substrate coated with the precursor in a CVD furnace and reacting under nitrogen protection at a reaction temperature of 450° C., a reaction time of 90 minutes, and a selenium powder evaporation temperature of 200° C.

[0096] (5) After the reaction is completed, the mixture is naturally cooled to room temperature to obtain high-quality single-crystalline two-dimensional semiconductor phase PtSe 2 Material.

[0097] Working principle: In the method for preparing two-dimensional semiconductor phase platinum diselenide single crystal material provided by the present invention, the liquid phase precursor can accurately control the stoichiometric ratio of the platinum source and the selenium source to ensure the uniformity of the reaction. Then, by spin coating or drop coating, a uniform precursor film can be formed on the substrate surface to form a high-quality single crystal PtSe 2 Provides a basis for growth.

[0098] The temperature of the CVD reaction is reduced to 400-550°C, which reduces material defects and side reactions caused by high temperature. This is conducive to the formation of high-quality single-crystalline PtSe 2 , while reducing energy consumption. By controlling the evaporation temperature of selenium powder and the carrier gas flow rate, the selenium vapor concentration is accurately adjusted to ensure sufficient supply of selenium source during the reaction and avoid selenium defects.

[0099] Finally, since the method of the present invention is applicable to a variety of substrates (such as silicon wafers, silicon dioxide substrates and flexible substrates), it can effectively improve the versatility of materials and the flexibility of device processing.

[0100] This specific embodiment is merely an explanation of the present invention and is not a limitation of the present invention. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed. However, as long as they are within the scope of the claims of the present invention, they are protected by the patent law.

Claims

1. A method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material, characterized by: The following steps are involved: S1. Liquid precursor preparation; S2. Substrate surface pretreatment; S3. Precursor fixation and nucleation; S4.CVD-gas-solid reaction; S5. Cooling and collection.

2. The method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material according to claim 1, characterized in that: The specific operation of preparing the liquid precursor in S1 is as follows: (1) dissolving a platinum salt and a selenium source in a solvent to form a uniform liquid precursor solution, wherein the solvent includes but is not limited to a hydrochloric acid solution with a concentration of 0.001-1M, a sodium hydroxide solution with a concentration of 0.001-1M, and deionized water, and the platinum salt includes but is not limited to chloroplatinic acid, platinum chloride, and platinum sulfate; (2) the molar ratio of the platinum salt to the selenium source is 2:1 to 1:4 to ensure precise control of the stoichiometric ratio; (3) The solution is fully dissolved and evenly mixed by heating, stirring, and heating ultrasonic treatment to avoid precipitation of large particles or stratification of the precursor solution.

3. The method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material according to claim 2, characterized in that: The specific operation of substrate pretreatment in S2 is as follows: (1) Select high-purity silicon wafers, silicon dioxide substrates or flexible substrates; (2) ultrasonic cleaning with acetone, isopropanol, and deionized water for 10 minutes in sequence to remove surface contaminants; (3) Blow dry the substrate with nitrogen to ensure the surface is clean and dry.

4. The method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material according to claim 3, characterized in that: The specific operation of the precursor coating in S3 is as follows: (1) Spin-coating the liquid precursor solution uniformly on the substrate surface; (2) Control the thickness of the precursor film by spin coating or drop coating, with a spin coating speed of 2000-4000 rpm and a time of 30-60 seconds; (3) After coating, pre-bake the substrate at 80-120°C for 5-10 minutes to remove the solvent.

5. The method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material according to claim 4, characterized in that: The specific operation of the CVD reaction in S4 is as follows: (1) placing the substrate coated with the precursor in a CVD furnace and reacting under the protection of an inert gas; (2) The reaction temperature is 400-550°C and the reaction time is 30-90 minutes; (3) Selenium vapor is generated by evaporating selenium powder at 200-300°C and transported to the reaction zone by a carrier gas; (4) By controlling the selenium powder evaporation temperature and carrier gas flow rate, the selenium vapor concentration is adjusted to ensure reaction uniformity.

6. The method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material according to claim 5, characterized in that: The specific operations of cooling and collecting in S5 are as follows: (1) After the reaction is completed, turn off the heating system and allow the furnace to cool naturally to room temperature; (2) removing the substrate to obtain high-quality single-crystalline two-dimensional semiconductor phase PtSe2 material; (3) The materials were characterized by optical microscopy, scanning electron microscopy (SEM), and Raman spectroscopy to ensure their crystalline quality and uniformity.

7. The method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material according to claim 2, characterized in that: When the liquid precursor is prepared, the concentration of platinum salt is 0.01-0.1 mol / L, and the concentration of selenium source is 0.02-0.4 mol / L.

8. The method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material according to claim 4, characterized in that: The spin coating speed is preferably 3000 rpm, and the spin coating time is preferably 30 seconds.

9. The method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material according to claim 5, characterized in that: The reaction temperature of the CVD reaction is preferably 500°C, the reaction time is preferably 60 minutes, and the selenium powder evaporation temperature is preferably 250°C.

10. The method for preparing a two-dimensional semiconductor phase platinum diselenide single crystal material according to claim 5, characterized in that: The carrier gas flow rate in the CVD reaction is 50-100 sccm.

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