Method for growing graphene on surface of metal chalcogenide and application

Abstract

The invention discloses a method for growing graphene on the surface of a metal chalcogenide and application, and belongs to the technical field of low-dimensional material growth. The invention aims to solve the problems that the preparation of a large-area, atomic-scale, flat and defect-free continuous heterojunction thin film cannot be realized by the existing method, and the application of the heterojunction thin film in an actual device is limited. According to the method for growing the graphene on the surface of the metal chalcogenide, the high-quality graphene can be directly grown on the surface of the metal chalcogenide by optimizing interface engineering and a carbon source supply strategy, so that an atomic-scale flat and defect-free continuous film is obtained; the graphene can be directly integrated into a device without an additional transfer step, and pollution and damage to the graphene and the substrate in the transfer process are effectively reduced or avoided. Besides, the method has the capability of simultaneously growing on a plurality of substrates, is high in process expandability, provides feasibility for large-scale production, and has a good industrial application prospect.

Description

Technical Field

[0001] The present invention belongs to the technical field of low-dimensional material growth, and particularly relates to a method for growing graphene on the surface of metal chalcogenides. Background Art

[0002] In the field of materials science, the heterojunction of metal chalcogenides and graphene has attracted much attention due to its unique physical properties and potential application values. In high-speed electronic devices, it can improve the electron migration rate and is expected to achieve faster data processing; for high-performance sensors, it can achieve highly sensitive detection of various substances by virtue of its special interfacial properties; in the aspect of novel optoelectronic devices, its unique energy band structure and optical properties enable it to have the opportunity to open up new application directions. However, the current methods for preparing the heterojunction of metal chalcogenides and graphene have obvious limitations.

[0003] The first common method is to stack the two by mechanical exfoliation. This method has prominent problems: a large number of defects are easily introduced during stacking, and these defects will interfere with the electron cloud distribution, resulting in unstable electrical properties of the heterojunction and also having an adverse impact on the absorption and emission of light; mechanical exfoliation and stacking rely on manual operation and it is difficult to achieve large-area preparation, which is a great obstacle in large-scale industrial production; moreover, this process has cumbersome steps, and has extremely high requirements for the cleanliness, temperature and humidity control of the experimental environment as well as the experience and skills of the operators, resulting in high preparation costs and low production efficiency.

[0004] The second method is to construct a sandwich structure, including first growing graphene on a metal substrate and then growing metal chalcogenides; or simultaneously depositing a carbon source, a metal element and a chalcogen element on the surface of a metal substrate to grow graphene in the interlayer. Although this method overcomes some of the disadvantages of the mechanical exfoliation method, there are still problems: the formed heterojunction has defects and it is difficult to prepare a large-area continuous thin film of the heterojunction of metal chalcogenides and graphene, which limits its application in scenarios such as flexible displays and large-area sensor arrays that require large-area materials; since graphene is sandwiched in the middle, the interaction between the metal substrate and graphene and the coverage of metal chalcogenides will change the electronic structure of graphene, resulting in the inability to fully exert its excellent electrical, mechanical and optical properties.

[0005] In summary, realizing high-quality continuous thin films of metal chalcogenides and graphene heterojunctions with large area, stable electrical properties, atomic-level flatness and no defects still faces technical bottlenecks, which limits their application in actual devices. Summary of the Invention

[0006] The object of the present invention is to solve the problem that the existing methods cannot realize the preparation of high-quality continuous metal chalcogenide and graphene heterojunction films with large area, stable electrical properties, atomic-level flatness and no defects, which limits the application of heterojunction films in actual devices, and to provide a method and application for growing graphene on the surface of metal chalcogenides.

[0007] In order to solve the above problems existing in the prior art, the present invention proposes a new preparation idea: first construct a perfect metal chalcogenide film, and then directly epitaxially grow graphene on its surface; this method can obtain a continuous heterojunction film with large area, flatness and high quality, where graphene is located on the surface layer of the metal chalcogenide; graphene is located on the outermost layer, avoiding performance degradation, not only maintaining its own excellent properties, but also generating a synergistic effect with the underlying metal chalcogenide, providing a better material basis for applications in related fields, and being of great value in scientific research and practical applications.

[0008] A method for growing graphene on the surface of metal chalcogenides is specifically completed according to the following steps:

[0009] I. Preparation of metal chalcogenide film:

[0010] Clean the metal substrate, and then deposit chalcogen elements on the surface of the cleaned metal substrate by molecular evaporation to obtain a metal chalcogenide film;

[0011] II. Growing graphene on the surface of the metal chalcogenide film:

[0012] In an ultra-high vacuum scanning tunneling microscope equipment, heat the metal chalcogenide film to 300 °C - 1200 °C, and at the same time feed carbon source gas through a micro-leak valve, and deposit for 1 min - 60 min at 300 °C - 1200 °C. A high-quality graphene layer grows on the surface of the metal chalcogenide to obtain a metal chalcogenide / graphene heterostructure, that is, a method for growing graphene on the surface of metal chalcogenides is completed.

[0013] An application of a metal chalcogenide / graphene layer heterostructure in electronic devices for exploring quantum materials or topological properties.

[0014] An application of a metal chalcogenide / graphene layer heterostructure as a catalyst in the catalytic field.

[0015] The principle of the present invention:

[0016] The present invention provides a method for directly epitaxially growing graphene on the surface of metal chalcogenides, aiming to solve the defect problems caused by mechanical exfoliation and stacking processes in the prior art, such as key technical bottlenecks like interface contamination, unstable electrical properties, and difficulty in achieving large-area preparation. The core of this method lies in first constructing a high-quality, continuous, and atomically flat metal chalcogenide thin film on a metal substrate. Subsequently, graphene is epitaxially grown on its surface to form a high-quality large-area heterojunction thin film covering it. Compared with the traditional exfoliation-stacking method, this method does not rely on the artificial transfer process, avoiding problems such as organic residues, wrinkles, and voids generated during the transfer process, ensuring the cleanliness of the heterojunction interface, and thus enhancing the stability of the interlayer interaction. In addition, the epitaxial growth process has good controllability, enabling the growth of continuous graphene thin films on the surface of metal chalcogenides over a large area, overcoming the technical obstacles of limited size and poor uniformity. More importantly, this structural design places graphene on the outermost layer of the heterostructure, not only avoiding the degradation of its performance due to the direct interference of the metal substrate but also effectively regulating its electronic structure with the help of the modulation effect of the bottom metal chalcogenide, thereby achieving a synergistic enhanced interface effect. This method not only breaks through the limitations of traditional preparation technologies but also provides a new solution for the construction of high-performance two-dimensional electronic and optoelectronic devices.

[0017] Advantages of the present invention:

[0018] The advantages of the present invention are that by directly epitaxially growing graphene on the surface of metal chalcogenides, graphene is located on the outermost layer of the heterostructure, which is conducive to the full retention and display of its intrinsic electrical, optical, and mechanical properties. At the same time, the underlying metal chalcogenide can regulate the electronic structure of graphene through interface coupling effects, such as introducing an interface potential field or adjusting the carrier concentration, thereby further enhancing the overall functional performance of the heterostructure. This method adopts an epitaxial growth strategy, avoiding problems such as interface contamination, grain boundary mismatch, and structural defects that may be brought about during the mechanical transfer process, and significantly improving the interface cleanliness and structural integrity. In addition, this method has good scale controllability and material compatibility, enabling the realization of high-quality, flat, and continuous heterostructure thin films with graphene on the surface of metal chalcogenides over a large area, providing an extensible basic platform for the construction of high-performance two-dimensional material devices. Description of the drawings

[0019] Figure 1 Scanning tunneling microscopy characterization image of the growth of a large-area atomically flat Cu2Se layer after depositing Se on the Cu(111) surface in Example 1;

[0020] Figure 2Scanning tunneling microscopy characterization image and low-energy electron diffraction pattern of directly growing large-area high-quality graphene on the Cu(111) / Cu2Se surface in Example 1;

[0021] Figure 3 Angle-resolved photoemission spectroscopy for the band structure regulation of directly growing large-area high-quality graphene on the Cu(111) / Cu2Se surface in Example 1. Specific implementation manners

[0022] Specific implementation manner 1: A method for growing graphene on a metal chalcogenide surface in this implementation manner is specifically completed according to the following steps:

[0023] I. Prepare a metal chalcogenide thin film:

[0024] Clean the metal substrate, and then deposit chalcogen elements on the surface of the cleaned metal substrate by molecular evaporation to obtain a metal chalcogenide thin film;

[0025] II. Grow graphene on the surface of the metal chalcogenide thin film:

[0026] In a scanning tunneling microscope device under ultra-high vacuum, heat the metal chalcogenide thin film to 300 °C to 1200 °C, and at the same time send carbon source gas through a micro-leak valve, deposit for 1 min to 60 min at 300 °C to 1200 °C, and a high-quality graphene layer grows on the surface of the metal chalcogenide to obtain a metal chalcogenide / graphene heterostructure, that is, a method for growing graphene on a metal chalcogenide surface is completed.

[0027] Specific implementation manner 2: The difference between this implementation manner and Specific implementation manner 1 is that: the chalcogen element described in step I is one or a mixture of several of S, Se, and Te. Other steps are the same as those in Specific implementation manner 1.

[0028] Specific implementation manner 3: The difference between this implementation manner and one of Specific implementation manner 1 or 2 is that: the metal substrate described in step I is Cu, Ag, Au, Rh, Ru, Ir, or Fe. Other steps are the same as those in Specific implementation manner 1 or 2.

[0029] Specific implementation manner 4: The difference between this implementation manner and one of Specific implementation manners 1 to 3 is that: the method for cleaning the metal substrate in step I is:

[0030] ①. Fix the metal substrate on a Ta metal holder and transfer it to a vacuum chamber;

[0031] ②. Heat the metal substrate in a vacuum environment, raise the temperature from room temperature to 600 °C to 900 °C, and keep it at 600 °C to 900 °C for 10 min to 30 min;

[0032] ③. Bombard the surface of the metal substrate with argon ions for 15 min to 20 min;

[0033] ④. Heat the metal substrate bombarded with argon ions in a vacuum environment. The temperature is raised from room temperature to 600 °C to 900 °C at a heating rate of 20 °C / min to 30 °C / min, and held at 600 °C to 900 °C for 10 min to 30 min;

[0034] ⑤. Repeat steps ③ to ④ several times to obtain a cleaned metal substrate. Other steps are the same as those in the first to third specific embodiments.

[0035] Specific Embodiment Five: The difference between this embodiment and any one of the first to fourth specific embodiments is that: the heating rate described in step ② is 20 °C / min to 30 °C / min. Other steps are the same as those in the first to fourth specific embodiments.

[0036] Specific Embodiment Six: The difference between this embodiment and any one of the first to fifth specific embodiments is that: in step ⑤, steps ③ to ④ are repeated 8 to 12 times. Other steps are the same as those in the first to fifth specific embodiments.

[0037] Specific Embodiment Seven: The difference between this embodiment and any one of the first to sixth specific embodiments is that: the method of molecular evaporation described in step one is: put the crucible containing chalcogen powder into the molecular beam evaporation source, keep it at 40 °C for 4 h to 5 h, and then raise the temperature from 40 °C to 200 °C to 280 °C at a heating rate of 2 °C / min to 4 °C / min, and deposit at 200 °C to 280 °C for 10 min to 30 min. Other steps are the same as those in the first to sixth specific embodiments.

[0038] Specific Embodiment Eight: The difference between this embodiment and any one of the first to seventh specific embodiments is that: the carbon source described in step two is acetylene, methane or ethylene. Other steps are the same as those in the first to seventh specific embodiments.

[0039] Specific Embodiment Nine: This embodiment is an application of a metal chalcogenide / graphene layer heterostructure in electronic devices for exploring quantum materials or topological properties.

[0040] Specific Embodiment Ten: This embodiment is an application of a metal chalcogenide / graphene layer heterostructure as a catalyst in the catalytic field.

[0041] The following examples are used to verify the beneficial effects of the present invention:

[0042] Example 1: A method for growing graphene on the surface of a metal chalcogenide, which is specifically completed according to the following steps:

[0043] I. Prepare a metal chalcogenide thin film:

[0044] Clean the metal substrate, and then deposit chalcogen element powder on the surface of the cleaned metal substrate by molecular evaporation to obtain a Cu2Se thin film;

[0045] The metal substrate described in Step 1 is a Cu(111) substrate;

[0046] The chalcogen element powder described in Step 1 is Se powder;

[0047] The method for cleaning the metal substrate in Step 1 is as follows:

[0048] ①. Fix the metal substrate on a Ta metal holder and transfer it to a vacuum chamber;

[0049] ②. Heat the metal substrate in a vacuum environment, raise the temperature from room temperature to 900 °C at a heating rate of 30 °C / min, and hold for 30 min at 900 °C;

[0050] ③. Bombard the surface of the metal substrate with argon ions for 20 min;

[0051] ④. Heat the metal substrate bombarded with argon ions in a vacuum environment, raise the temperature from room temperature to 900 °C at a heating rate of 30 °C / min, and hold for 30 min at 900 °C;

[0052] ⑤. Repeat Steps ③ to ④ 10 times to obtain the cleaned metal substrate;

[0053] The method of molecular evaporation described in Step 1 is: put the crucible containing chalcogen element powder into a molecular beam evaporation source, keep it at 40 °C for 5 h, then raise the temperature from 40 °C to 250 °C at a heating rate of 2 °C / min, and deposit for 20 min at 250 °C;

[0054] II. Grow graphene on the surface of the metal chalcogenide thin film:

[0055] In a scanning tunneling microscope equipment under ultra-high vacuum, heat the Cu2Se thin film to 800 °C, and at the same time send acetylene gas through a micro-leak valve. Deposit for 20 min under the conditions of acetylene atmosphere (8×10 -6 mbar) and 800 °C. A high-quality graphene layer grows on the surface of Cu2Se to obtain a Cu2Se / graphene heterostructure, that is, a method for growing graphene on the surface of a metal chalcogenide is completed.

[0056] Figure 1 It is the scanning tunneling microscope characterization image of growing a large-area atomically flat Cu2Se layer after depositing Se on the Cu(111) surface in Example 1;

[0057] From Figure 1The moiré Cu2Se structure with high coverage can be seen.

[0058] Figure 2 They are the scanning tunneling microscopy characterization image and low-energy electron diffraction pattern of directly growing large-area high-quality graphene on the Cu(111) / Cu2Se surface in Example 1;

[0059] From Figure 2 It can be seen that high-quality Cu2Se / graphene heterostructures are grown on the Cu2Se surface.

[0060] By testing the metal chalcogenide / graphene heterostructure obtained in Example 1 through angle-resolved photoemission spectroscopy, it is found that the structure forms a double-cone structure located at the Fermi level as Figure 3 shown. This structure indicates that there is a significant interaction between the surface electronic structure of Cu2Se and the electronic structure of graphene, resulting in unique electronic properties. This double-cone structure not only affects the electronic transport properties of the composite material but also may provide new ideas in the future design of electronic devices, especially in the exploration of quantum materials and topological properties.

[0061] Example 2: A method for growing graphene on the surface of a metal chalcogenide, which is specifically completed according to the following steps:

[0062] I. Preparation of a metal chalcogenide thin film:

[0063] Clean the metal substrate, and then deposit chalcogen element powder on the surface of the cleaned metal substrate by molecular evaporation to obtain an Ag2Se thin film;

[0064] The metal substrate described in step I is an Ag(111) substrate;

[0065] The chalcogen element powder described in step I is Se powder;

[0066] The method for cleaning the metal substrate in step I is:

[0067] ①. Fix the metal substrate on a Ta metal holder and transfer it to a vacuum chamber;

[0068] ②. Heat the metal substrate in a vacuum environment, raise the temperature from room temperature to 700 °C at a heating rate of 30 °C / min, and keep it at 700 °C for 30 min;

[0069] ③. Bombard the surface of the metal substrate with argon ions for 20 min;

[0070] ④. Heat the metal substrate bombarded with argon ions in a vacuum environment, raise the temperature from room temperature to 700 °C at a heating rate of 30 °C / min, and keep it at 700 °C for 30 min;

[0071] ⑤ Repeat steps ③ - ④ ten times to obtain a cleaned metal substrate;

[0072] The method of molecular evaporation described in step one is as follows: Place the crucible containing chalcogen powder into the molecular beam evaporation source, hold it at 40 °C for 5 h, then increase the temperature from 40 °C to 250 °C at a rate of 2 °C / min, and deposit for 20 min at 250 °C;

[0073] II. Grow graphene on the surface of the metal chalcogenide thin film:

[0074] In a scanning tunneling microscope device under ultra - high vacuum, heat the Cu2Se thin film to 800 °C, and at the same time introduce acetylene gas through a micro - leak valve. Deposit for 20 min under the conditions of an acetylene atmosphere (1×10 -6 mbar) and 800 °C. A high - quality graphene layer grows on the surface of the Ag2Se thin film to obtain an Ag2Se thin film / graphene heterostructure, thus completing a method for growing graphene on the surface of a metal chalcogenide.

Claims

1. A method for growing graphene on the surface of a metal chalcogenide, characterized in that The method is specifically completed according to the following steps: I. Preparation of metal chalcogenide thin film: Clean the metal substrate, and then deposit chalcogen elements on the surface of the cleaned metal substrate by molecular evaporation to obtain a metal chalcogenide thin film; II. Growth of graphene on the surface of the metal chalcogenide thin film: In a scanning tunneling microscope device under ultra-high vacuum, heat the metal chalcogenide thin film to 300 °C - 1200 °C, and at the same time feed carbon source gas through a micro-leak valve, deposit for 1 min - 60 min at 300 °C - 1200 °C, and a high-quality graphene layer grows on the surface of the metal chalcogenide to obtain a metal chalcogenide / graphene heterostructure, that is, a method for growing graphene on the surface of a metal chalcogenide is completed.

2. The method for growing graphene on the surface of a metal chalcogenide according to claim 1, characterized in that The chalcogen element described in step I is one or a mixture of several of S, Se, and Te.

3. A method for growing graphene on the surface of a metal chalcogenide according to claim 1, characterized in that The metal substrate described in step I is Cu, Ag, Au, Rh, Ru, Ir, or Fe.

4. A method for growing graphene on the surface of a metal chalcogenide according to claim 1, characterized in that The method for cleaning the metal substrate in step I is: ①. Fix the metal substrate on a Ta metal holder and transfer it to a vacuum chamber; ②. Heat the metal substrate in a vacuum environment, raise the temperature from room temperature to 600 °C - 900 °C, and keep it at 600 °C - 900 °C for 10 min - 30 min; ③. Bombard the surface of the metal substrate with argon ions for 15 min - 20 min; ④. Heat the metal substrate bombarded with argon ions in a vacuum environment, raise the temperature from room temperature to 600 °C - 900 °C, with a heating rate of 20 °C / min - 30 °C / min, and keep it at 600 °C - 900 °C for 10 min - 30 min; ⑤. Repeat steps ③ - ④ several times to obtain the cleaned metal substrate.

5. A method for growing graphene on the surface of a metal chalcogenide according to claim 4, characterized in that The heating rate described in step ② is 20 °C / min - 30 °C / min.

6. The method for growing graphene on the surface of a metal chalcogenide according to claim 4, characterized in that In step ⑤, repeat steps ③ - ④ 8 - 12 times.

7. A method for growing graphene on the surface of a metal chalcogenide according to claim 1, characterized in that The molecular evaporation method described in step I is: put the crucible containing chalcogen element powder into a molecular beam evaporation source, keep it at 40 °C for 4 h - 5 h, and then raise the temperature from 40 °C to 200 °C - 280 °C at a heating rate of 2 °C / min - 4 °C / min, and deposit for 10 min - 30 min at 200 °C - 280 °C.

8. A method for growing graphene on the surface of a metal chalcogenide according to claim 1, characterized in that The carbon source described in step II is acetylene, methane, or ethylene.

9. An application of growing graphene on the surface of a metal chalcogenide prepared by the preparation method according to claim 1, characterized in that A metal chalcogenide / graphene layer heterostructure is applied in exploring quantum materials or electronic devices with topological properties.

10. An application for growing graphene on the surface of a metal chalcogenide prepared by the preparation method according to claim 1, characterized in that A metal chalcogenide / graphene layer heterostructure is applied as a catalyst in the catalytic field.

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