A method for low-temperature growth of graphene on a non-metallic substrate surface

Abstract

The present application relates to graphene material and its chemical vapor deposition (CVD) preparation technology, specifically to a method for low-temperature growth of graphene on non-metal substrate surface, which is suitable for preparation of single-layer and multi-layer graphene without using metal catalyst and high-temperature condition. The method uses organic matter containing delocalized bond as an additive of carbon source, and utilizes the delocalized bond to promote the reconfiguration of carbon source on the non-metal surface to form graphene. By adding the organic matter containing delocalized bond, the nucleation and growth of graphene on the non-metal substrate surface under lower temperature condition can be effectively promoted without using metal catalyst and high temperature. By using the method described in the present application, high-quality graphene can be grown on the non-metal substrate at low temperature, thereby avoiding the adverse effects of conventional transfer process on the performance of graphene devices.

Description

Technical Field

[0001] This invention relates to graphene materials and their chemical vapor deposition (CVD) preparation technology, specifically a method for low-temperature growth of graphene on a non-metallic substrate, suitable for preparing single-layer and multi-layer graphene without the use of metal catalysts and high-temperature conditions. Background Technology

[0002] Developing controllable methods for preparing high-quality graphene is fundamental to its applications. Among these methods, CVD (Chemical Vapor Deposition) offers significant advantages, including simplicity, high-quality graphene, large-area growth capability, and compatibility with various substrates, making it a promising candidate for graphene-based electronic and optoelectronic devices. Electronic and optoelectronic devices typically require graphene to be placed on non-metallic substrates. Current CVD methods primarily use metals as growth substrates to prepare high-quality graphene, necessitating the transfer of graphene to a non-metallic substrate. This process is prone to introducing impurities, polymer residues, wrinkle formation, and reduced uniformity. Furthermore, residual metal substrate contamination is a concern, making it incompatible with silicon-based electronic device fabrication processes.

[0003] To fundamentally address these issues, it is necessary to develop CVD methods for directly preparing high-quality graphene on non-metallic substrates. The challenge lies in the fact that the catalytic activity of non-metallic substrates is far lower than that of metals, making it difficult to effectively decompose carbon sources. While metal-assisted catalysis or high-temperature growth (above 1100℃) can yield high-quality graphene, these methods suffer from metal residue contamination and incompatibility with semiconductor substrates such as silicon, respectively. Furthermore, plasma-enhanced CVD can prepare graphene without metal catalysis and at lower temperatures, but the material exhibits numerous defects. Therefore, achieving the growth of high-quality graphene on non-metallic materials is crucial for advancing the application of graphene in the electronics and optoelectronics fields. Summary of the Invention

[0004] The purpose of this invention is to provide a method for low-temperature growth of graphene on a non-metallic substrate, which can produce high-quality graphene without the use of metal catalysts and high-temperature conditions.

[0005] The technical solution of this invention is:

[0006] A method for low-temperature growth of graphene on a non-metallic substrate involves using organic compounds containing delocalized bonds as additives for the carbon source in the chemical vapor deposition process. The delocalized bonds are used to reconstruct the carbon source, transforming it into graphene on the non-metallic surface.

[0007] The method for low-temperature growth of graphene on a non-metallic substrate uses organic compounds containing delocalized bonds, including but not limited to Zeiss salts, diborane, xenon fluoride, or benzaldehyde.

[0008] The method for low-temperature growth of graphene on a non-metallic substrate controls the degree of graphene crystallization by increasing the relative concentration of organic matter containing delocalized bonds, thereby achieving the transformation from amorphous carbon to pyrolytic carbon and finally to graphene.

[0009] The method for low-temperature growth of graphene on a non-metallic substrate involves adding organic compounds containing delocalized bonds to a carbon source through mixing or organic chemical reactions; for the mixing method, the typical concentration of the organic compounds containing delocalized bonds in the carbon source is greater than 0.1 wt%.

[0010] The method for low-temperature growth of graphene on a non-metallic substrate utilizes organic compounds containing delocalized bonds to significantly reduce the temperature required for preparing graphene on a non-metallic surface by chemical vapor deposition, enabling the preparation of graphene at temperatures below 800°C.

[0011] The method for low-temperature growth of graphene on a non-metallic substrate includes inorganic and organic materials, including but not limited to silicon, silicon oxide, aluminum oxide, silicon nitride, boron nitride, silicon carbide, mica, polymethyl methacrylate, polyethylene naphthalate or composites thereof; the structure of the non-metal includes crystalline or amorphous structures, and the morphology includes bulk, porous materials or powders.

[0012] The method for low-temperature growth of graphene on a non-metallic substrate involves preparing single-crystal graphene on the surface of a non-metallic substrate that is a single crystal or has atomic-level steps with a single orientation. This is achieved by utilizing the interaction between organic matter containing delocalized bonds and the non-metal.

[0013] The method for low-temperature growth of graphene on a non-metallic substrate, wherein the carbon source used in the chemical vapor deposition method is an organic compound, including but not limited to alkanes, alkenes, alkynes, alcohols, esters, ethers, phenols, aldehydes or carboxylic acids.

[0014] The method for low-temperature growth of graphene on a non-metallic substrate, wherein the method prepares single-layer graphene or multi-layer graphene.

[0015] The method for low-temperature growth of graphene on a non-metallic substrate involves preparing lattice-doped graphene using delocalized organic compounds containing specific doping elements. The specific doping elements are one or more of nitrogen, boron, phosphorus, and sulfur, and the doping amount is usually less than 10 wt%.

[0016] The design concept of this invention is:

[0017] In the process of growing graphene on non-metallic surfaces by chemical vapor deposition, organic compounds containing delocalized bonds are used as additives for carbon sources. The delocalized bonds are used to reconstruct carbon atoms in the carbon source, transforming them into graphene on the non-metallic surface.

[0018] The features and beneficial effects of this invention are:

[0019] 1. This invention utilizes the reconfiguration effect of delocalized bonds in organic matter on carbon atoms to convert carbon sources on non-metallic substrates into graphene, which can effectively promote the nucleation and growth of graphene on the surface of non-metallic substrates.

[0020] 2. This invention does not require the use of metal catalysts or high-temperature conditions, and can directly grow high-quality graphene on the surface of a non-metallic substrate.

[0021] 3. Using the method described in this invention, high-quality graphene can be grown at low temperatures on a non-metallic substrate, thereby avoiding the adverse effects of conventional transfer processes on the performance of graphene devices.

[0022] 4. This invention is particularly applicable to silicon, silicon oxide, aluminum oxide, boron nitride and mica matrix, etc. Attached Figure Description

[0023] Figure 1 This is an image (optical microscope image) of the monolayer graphene film obtained in Example 1.

[0024] Figure 2 The image shows the surface morphology of the multilayer graphene-coated silicon oxide powder obtained in Example 2 (scanning electron microscope image). Detailed Implementation

[0025] The present invention will be further described in detail below through embodiments.

[0026] Example 1

[0027] This invention employs a horizontal reactor to grow graphene. The horizontal reactor has a gas inlet and a gas outlet at both ends. The substrate (in this embodiment, a SiO2 / Si substrate, i.e., a substrate formed by depositing silicon dioxide on the surface of a silicon wafer) is placed in the high-temperature zone of the horizontal reactor. First, the SiO2 / Si substrate is sequentially immersed in deionized water, acetone, and isopropanol for ultrasonic cleaning for 30 minutes each. After cleaning, the SiO2 / Si substrate was placed in the central area (reaction zone, where thermocouples monitor the furnace temperature in real time) of a horizontal reactor (furnace tube diameter 22 mm, reaction zone length 40 mm); it was heated to 750℃ in an argon atmosphere (argon flow rate 200 mL / min, heating rate 35℃ / min) for 5 minutes; after heat treatment, methane and argon carrying Zeiss salt were introduced (gas flow rates of 5 mL / min for methane and 200 mL / min for argon, Zeiss salt concentration 0.5 wt%) to begin graphene growth for 20 minutes. After growth, it was cooled to room temperature at a rate of 10℃ / s to obtain a single-layer graphene film. See [link to relevant documentation]. Figure 1 .Depend on Figure 1It can be seen that a relatively uniform monolayer graphene film was grown on the SiO2 / Si substrate.

[0028] Example 2

[0029] This invention employs a vertical reactor to grow graphene. The vertical reactor has both a gas inlet and a gas outlet. The non-metallic matrix material (silicon oxide powder in this embodiment) is placed in the high-temperature zone of the vertical reactor. First, the silicon oxide powder is sequentially ultrasonically cleaned in deionized water, acetone, and isopropanol for 30 minutes each. After cleaning, the silicon oxide powder is placed in the central area of ​​the vertical reactor (furnace tube diameter 50 mm, reaction zone length 150 mm); it is heated to 500°C in an argon atmosphere (argon flow rate 200 ml / min, heating rate 35°C / min) for 10 minutes. After heat treatment, ethylene and argon gas carrying benzaldehyde are introduced (ethylene flow rates 5 ml / min, argon flow rates 200 ml / min, benzaldehyde concentration 2 wt%) to begin graphene growth. The growth time is 30 minutes. After growth, it is cooled to room temperature at a rate of 10°C / s to obtain multilayer graphene-coated silicon oxide powder. See [link to relevant documentation]. Figure 2 .Depend on Figure 2 It can be seen that a uniformly coated multilayer graphene layer is formed on the surface of the silica powder.

[0030] Example 3

[0031] The non-metallic substrate material (in this embodiment, a single-crystal alumina wafer) was placed in the high-temperature zone of a vertical reactor. First, the single-crystal alumina wafer was ultrasonically cleaned for 30 minutes each in deionized water, acetone, and isopropanol. After cleaning, the single-crystal alumina wafer was placed in the central area of ​​the reactor (furnace tube diameter 50 mm, reaction zone length 150 mm); it was heated to 780°C in an argon atmosphere (argon flow rate 200 mL / min, heating rate 35°C / min) for 10 minutes; after heat treatment, methane and argon carrying benzaldehyde were introduced (gas flow rates of ethylene 5 mL / min, argon 200 mL / min, benzaldehyde concentration 2 wt%) to begin graphene growth for 30 minutes. After growth, it was cooled to room temperature at a rate of 10°C / s to obtain single-crystal graphene.

[0032] Example 4

[0033] This invention employs a horizontal reactor to grow graphene. The horizontal reactor has a gas inlet and a gas outlet at each end. The substrate (in this embodiment, a polycrystalline alumina substrate) is placed in the high-temperature zone of the horizontal reactor. First, the alumina substrate is sequentially ultrasonically cleaned in deionized water, acetone, and isopropanol for 30 minutes each. After cleaning, the polycrystalline alumina substrate is placed in the central area (reaction zone, where a thermocouple monitors the furnace temperature in real time) of the horizontal reactor (furnace tube diameter 22 mm, reaction zone length 40 mm). It is then heated to 600°C in an argon atmosphere (argon flow rate 200 mL / min, heating rate 35°C / min) for 5 minutes. After heat treatment, ethylene and argon carrying diborane are introduced (ethylene flow rates 5 mL / min, argon flow rates 200 mL / min, diborane concentration 1 wt%) to begin graphene growth. The growth time is 60 minutes. After growth, the substrate is cooled to room temperature at a rate of 10°C / s to obtain a boron-doped multilayer graphene film.

[0034] The results of the embodiments show that the present invention employs a chemical vapor deposition method to grow graphene on a non-metallic substrate. It uses organic compounds containing delocalized bonds as catalysts to convert carbon sources into graphene. By adding organic compounds containing delocalized bonds, the nucleation and growth of graphene on the surface of the non-metallic substrate can be effectively promoted at lower temperatures, thus avoiding the use of metal catalysts and high-temperature conditions. Using the method described in this invention, high-quality graphene and doped graphene can be grown on non-metallic substrates at temperatures below 800°C.

Claims

1. A method for low-temperature growth of graphene on a non-metallic substrate, characterized in that, In the reaction of growing graphene on a non-metallic substrate using chemical vapor deposition, organic compounds containing delocalized bonds are used as carbon source additives. The organic compounds containing delocalized bonds are Zeiss salt, diborane, xenon fluoride, or benzaldehyde. The carbon source is transformed into graphene on the non-metallic surface by utilizing the reconstruction effect of delocalized bonds on the carbon source. The degree of crystallinity of graphene can be controlled by increasing the relative concentration of organic matter containing delocalized bonds, thereby achieving the transformation from amorphous carbon to pyrolytic carbon and finally to graphene. Organic compounds containing delocalized bonds are added to a carbon source through mixing or organic chemical reactions; for mixing, the typical concentration of the organic compounds containing delocalized bonds in the carbon source is greater than 0.1 wt%. Using organic compounds containing delocalized bonds significantly reduces the temperature required for preparing graphene on non-metallic surfaces by chemical vapor deposition, enabling the preparation of graphene at temperatures below 800℃.

2. The method for low-temperature growth of graphene on a non-metallic substrate according to claim 1, characterized in that, The non-metals used encompass both inorganic and organic materials, including but not limited to silicon, silicon oxide, aluminum oxide, silicon nitride, boron nitride, silicon carbide, mica, polymethyl methacrylate, polyethylene naphthalate, or composites thereof; the structures of the non-metals include crystalline or amorphous structures, and the forms include bulk, porous materials, or powders.

3. The method for low-temperature growth of graphene on a non-metallic substrate according to claim 2, characterized in that, When the non-metallic matrix is ​​a single crystal or has atomic-level steps with a single orientation on its surface, single-crystal graphene can be prepared on its surface by utilizing the interaction between organic materials containing delocalized bonds and non-metals.

4. The method for low-temperature growth of graphene on a non-metallic substrate according to claim 1, characterized in that, Chemical vapor deposition uses organic carbon sources, including but not limited to alkanes, alkenes, alkynes, alcohols, esters, ethers, phenols, aldehydes, or carboxylic acids.

5. The method for low-temperature growth of graphene on a non-metallic substrate according to claim 1, characterized in that, This method can be used to prepare single-layer or multi-layer graphene.

6. The method for low-temperature growth of graphene on a non-metallic substrate according to any one of claims 1 to 5, characterized in that, Lattice-doped graphene is prepared by using delocalized organic compounds containing specific doping elements; the specific doping elements are one or more of nitrogen, boron, phosphorus and sulfur, and the doping amount is usually less than 10 wt%.

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