CN112125298A - A kind of substrate rapid screening method of vertical structure graphene - Google Patents

Abstract

The invention discloses a method for rapidly screening a substrate of vertical structure graphene. Placed on the sample stage in the reaction chamber of the jet plasma; 3) After the reaction chamber was evacuated to a vacuum, Ar gas was introduced, and after the pressure of the reaction chamber was adjusted to 200-1500 Pa, the plasma was excited, and then H was introduced ₂ and carbon-containing reactive gas; the present invention can grow vertical structure graphene under the same plasma environment at one time on the substrate area after pretreatment of various materials, and can also grow different plasma conditions by means of micro-region multi-point The vertical structure of graphene under.

Description

A kind of substrate rapid screening method of vertical structure graphene

technical field

The invention relates to the technical field of vertical structure graphene preparation, in particular to a substrate rapid screening method for vertical structure graphene.

Background technique

Vertical-oriented graphene (vertical-oriented graphene) is a member of the carbon material family, also known as carbon nanoflakes, which is formed by vertical growth of graphene nanoflakes composed of several layers of graphene It is a 3D material with rich edges, and the width and height of a single nanosheet can reach 0.1 to tens of micrometers, but the thickness is generally only a few nanometers or less than 1nm. As a layered material with atomic thickness, vertical structure graphene has large specific surface area, abundant sharp edges, high electron mobility, and high sensitivity to electron perturbation, etc., and is widely used in electrocatalysis, energy storage, etc. , sensors, etc.

At present, the synthesis method of vertical structure graphene mainly adopts plasma-enhanced chemical vapor deposition (plasma-enhanced chemical vapor deposition). Under the combined action of the electric field, graphene with a vertical structure gradually grows on the surface of the substrate. The whole growth process is generally divided into three stages: nucleation, growth and termination. PECVD has many advantages in nanostructure growth: relatively low substrate temperature, highly free growth selectivity, and good nanostructure mode control. These advantages make PECVD the most suitable method for growing vertical structure graphene. Due to the different plasma excitation methods, it can be divided into: planar inductively coupled plasma chemical vapor deposition (ICP-PECVD), radio frequency plasma enhanced chemical vapor deposition (RF-PECVD), Microwave Plasma Enhanced Chemical Vapor Deposition (MW-PECVD), Electron Beam Excited Plasma Enhanced Chemical Vapor Deposition (EBE-PECVD), Capacitively Coupled Plasma Enhanced Chemical Vapor Deposition (CCPE-PECVD), Helical Wave Plasma Chemical Vapor Deposition. Some people also use hot wire chemical vapor deposition (HF-CVD) and some self-built devices such as the device disclosed in Patent No. CN202465870U.

Although the growth of vertical graphene is not as demanding as the growth of ordinary two-dimensional graphene, which requires catalytic substances, due to the degree of lattice mismatch between the substrate material and the vertical graphene, the type of substrate material will affect the The actual growth process of vertical structure graphene has a great influence, which in turn affects the prepared morphology and structure, involving the initial nucleation and growth process. In the traditional preparation process of vertical structure graphene, one experiment can only realize the process condition exploration of one substrate. The process exploration time under various substrate conditions is expensive and inefficient. Therefore, it is necessary to develop a method that can A method for rapid and efficient screening of substrates.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to overcome the above shortcomings of the prior art: to provide a substrate rapid screening method for vertical structure graphene.

The technical solution of the present invention is as follows: a substrate rapid screening method of vertical structure graphene, comprising the following steps:

1) Divide areas on the substrate surface and use different material deposition pretreatments for different areas;

2) Place the pretreated substrate on the sample stage in the reaction chamber of the jet plasma;

3) After the reaction chamber is evacuated to a vacuum, Ar gas is introduced, and after adjusting the pressure of the reaction chamber to 200-1500 Pa, the plasma torch is excited, and then H ₂ and carbon-containing reaction gas are introduced;

4) By using the plasma torch of jet plasma to deposit vertical structure graphene in the substrate area after deposition pretreatment with different materials, the substrate material that meets the requirements can be quickly screened according to the growth characteristics of vertical structure graphene in different regions.

The jet plasma is an inductively coupled jet plasma generated by a helical coil method or a jet plasma generated by a direct current arc.

In step 1), the method of deposition pretreatment on the surface of the substrate is one of vacuum thin film deposition equipment such as thermal evaporation, E-beam or magnetron sputtering.

In step 1), the pre-processed material deposited on the surface of the substrate is metal or metal oxide.

The substrate in step 1) is polished and cleaned before being placed on the sample stage.

Specifically, the substrate cleaning method is ultrasonic cleaning in acetone, ethanol, and deionized water for 5-15 minutes, respectively.

In step 3), the distance between the sample stage and the jetting outlet of the plasma torch is 20-60 mm.

The flow rates of the gases introduced in step 2) are respectively Ar: 10-25 slm, H ₂ : 0-0.9 slm, and carbon-containing reaction gas: 10-200 sccm.

The carbon-containing reaction gas is one or more of CH ₄ , C ₂ H ₂ , C ₂ H ₄ , ethanol, and CO ₂ .

The vertical structure graphene deposited in different regions in step 4) can be deposited under the same growth condition plasma, or can be deposited under the plasma of different growth conditions realized by the micro-area multi-point method.

The beneficial effects of the present invention are as follows: the present invention firstly performs deposition pretreatment of various materials in different regions of the substrate, and then uses plasma spray deposition to achieve deposition of the same or different growth conditions in different regions. The pretreatment of the substrate can be realized by vacuum thin film deposition methods such as electron beam evaporation, magnetron sputtering, thermal evaporation, etc.

The invention can grow the vertical structure graphene under the same plasma environment at one time on the substrate area pretreated with various materials, and can also grow the vertical structure graphene under different plasma conditions by means of micro-region multi-point.

Through one experiment, the exploration of multiple process combination conditions can be realized, and the rapid screening of substrates with crystal growth catalytic effect can be realized, which greatly speeds up the experimental efficiency and accelerates the development and research of new materials and processes.

The utilization rate of the substrate material is improved, and the material cost and time cost are saved.

Description of drawings

FIG. 1 is a schematic diagram of a substrate surface process combination in Embodiment 1. FIG.

FIG. 2 is a schematic diagram of a substrate surface process combination in Embodiment 2. FIG.

FIG. 3 is a scanning electron microscope image of growth area 1 in Example 2. FIG.

FIG. 4 is the Raman spectrum of the sample of Example 2. FIG.

FIG. 5 is a scanning electron microscope image of the sample of Example 2. FIG.

FIG. 6 is a scanning electron microscope image of the sample of Example 2. FIG.

FIG. 7 is a scanning electron microscope image of growth area 2 in Example 2. FIG.

FIG. 8 is a scanning electron microscope image of growth region 2 in Example 2. FIG.

FIG. 9 is the Raman spectrum of the growth region 2 of Example 2. FIG.

FIG. 10 is a scanning electron microscope image of growth area 2 in Example 2. FIG.

Detailed ways

The present invention will be described in further detail below with specific examples, but the present invention is not limited to the following specific examples.

Example 1

The jet plasma equipment may specifically be the inductively coupled plasma spray gun and the plasma equipment disclosed in the patent CN104867801A or the equipment disclosed in the document [Carbon Volume 147, June 2019, Pages 341-347].

It was prepared using a high-density jet plasma generated by inductive coupling, and the plasma jet outlet was about 30 mm away from the sample stage. After cleaning the silicon wafer substrate in acetone, ethanol, and deionized water for 10-20min in turn, use an electron beam E-Beam device to perform different metal evaporation pretreatment on its surface through a mask, as shown in Figure 1, the substrate It is divided into 4 areas, number 1 is the electron beam nickel (Ni) area, number 2 is aluminum (Al) area, number 3 is palladium (Pd) area, number 4 is gold (Au) area, and then, The pretreated substrate is placed on the sample stage in the reaction chamber, and a plasma gas source is introduced into the reaction chamber to excite it to generate plasma. The gas flow rates used were 21 slm for argon, 0.9 slm for H ₂ and 50 sccm for CH ₄ , respectively, and the pressure of the reaction chamber was adjusted to 800 (±5) Pa, and the applied RF power was 18 kw. The same growth conditions were carried out on the substrate. Vertical structure graphene deposition.

Example 2

The high-density jet plasma was prepared using a DC arc, and the plasma jet outlet was about 40 mm away from the sample stage. This embodiment is basically the same as Embodiment 1, the difference is that the substrate material is divided into 25 areas, as shown in FIG. 2 , different areas are pretreated by thermal evaporation for evaporation of different materials, and a single deposition is performed. The experiment can explore the effect of different surface treatments on the nucleation and growth of vertical graphene. Through the micro-area multi-point method, different regions are deposited with different growth conditions: the gas flow rates used in regions 1-5 are argon 21 slm, H ₂ 0.9slm, CH ₄ 50sccm, and the gas flow used in regions 6-10 are argon Gas 20slm, H ₂ 0.6slm, CH ₄ 60sccm, the gas flow rates used in the 11-15 areas are argon 21slm, H ₂ 0.3slm, CH ₄ 50sccm, and the gas flows used in the 16-20 areas are argon 20slm, H ₂ 0.3 slm, CH ₄ 90sccm, the gas flow rates used in 21-25 areas are argon 21slm, H ₂ 0.9slm, CH ₄ 30sccm.

For Example 1, taking the areas numbered 1 and 2 as an example, the growth parameters were set the same: argon gas 21slm, hydrogen 0.9slm, methane gas 50sccm, the sample stage was about 30mm from the plasma cavity mouth, and the power of the radio frequency power supply was 18kw.

For growth region 1 (the substrate surface is not pretreated by evaporation), when the deposition time is 5s, the mixed buffer layer of amorphous graphite and α-C has been formed, and there are some nucleation sites on the buffer layer at this time And the nano-island, the scanning electron microscope picture is shown in Figure 3.

When the deposition time is 7s, it can be seen that a complete vertical structure graphene layer has been formed on the surface of the substrate according to the Raman pattern and scanning electron microscope analysis of the sample, as shown in Figure 4 and Figure 5.

With the further increase of the deposition time, the density of the vertical graphene nanosheets grown on the substrate became larger, and the surface micromorphology was similar, as shown in Figure 6.

For growth region 2 (nickel plating on the surface of the substrate is about 100 nm), when the deposition time is 3 s, a mixed buffer layer of amorphous graphite and α-C has been formed, and a large number of nucleation sites can be observed on the buffer layer at this time. and the grown nano-islands, the scanning electron microscope images are shown in Fig. 7 and Fig. 8.

When the deposition time is 5s, it can be seen that a complete vertical structure graphene layer has been formed on the surface of the substrate according to the Raman pattern and scanning electron microscope analysis of the sample, as shown in Figure 9 and Figure 10.

Comparing the area No. 1 (no metal evaporation pretreatment on the substrate surface) and No. 2 (electron beam nickel plating about 100 nm on the substrate surface) area, it can be seen that after the nickel plating pretreatment on the substrate surface, the vertical structure graphene nucleation time It is shortened from about 5s to about 3s, which significantly accelerates the nucleation of vertical structure graphene on the surface of the substrate and improves the preparation efficiency of vertical structure graphene.

For Example 2

For the 25 micro-regions pretreated with different materials, the growth conditions are different, and the vertical structure graphene deposition under different conditions can be carried out in different regions of the substrate through multi-point deposition, that is, a single deposition experiment has completed a variety of materials. Exploration of the effect of vertical structure graphene growth, enabling rapid screening of substrates.

The above are only characteristic implementation examples of the present invention, and do not constitute any limitation to the protection scope of the present invention. All technical solutions formed by equivalent exchange or equivalent replacement fall within the protection scope of the present invention.

Claims (10)

1. A method for rapidly screening a substrate of graphene with a vertical structure is characterized by comprising the following steps:

1) dividing regions on the surface of the substrate and respectively adopting different materials for deposition pretreatment on different regions;

2) placing the pretreated substrate on a sample table in a reaction chamber of the jet plasma;

3) pumping the reaction chamber to vacuum, introducing Ar gas, adjusting the pressure of the reaction chamber to 200-1500 Pa, exciting plasma, and introducing H₂And a carbon-containing reaction gas;

4) the vertical-structure graphene is deposited in the substrate area after deposition pretreatment of different materials through the jet plasma, and the substrate material meeting the requirements can be rapidly screened according to the growth characteristics of the vertical-structure graphene in different areas.

2. The method for rapidly screening the substrate with the vertical structure graphene according to claim 1, wherein the jet plasma is an inductively coupled jet plasma generated by a spiral coil method or a jet plasma generated by a direct current arc.

3. The method for rapidly screening the substrate with the vertical structure graphene according to claim 1, wherein in the step 1), the method for deposition pretreatment on the surface of the substrate is one of thermal evaporation, E-beam or magnetron sputtering vacuum thin film deposition.

4. The method for rapidly screening the substrate with the vertical structure graphene according to claim 1, wherein in the step 1), the material deposited and pretreated on the surface of the substrate is an elemental metal or an alloy.

5. The method for rapidly screening the substrate of the vertical structure graphene according to claim 1, wherein the substrate in the step 1) is cleaned before being placed on a sample stage.

6. The method for rapidly screening the substrate of the graphene with the vertical structure according to claim 5, wherein the substrate is cleaned by ultrasonic cleaning in acetone, ethanol and deionized water for 5-15 minutes.

7. The method for rapidly screening the substrate of the vertical structure graphene according to claim 1, wherein the distance between the sample stage and the plasma torch jet outlet in the step 3) is 20-60 mm.

8. The method for rapidly screening the substrate of the graphene with the vertical structure according to claim 1, wherein the flow rates of the gas introduced in the step 3) are Ar: 10-25 slm, H₂: 0-0.9 slm, carbon-containing reactant gas: 10-200 sccm.

9. The method for rapidly screening the substrate of the graphene with the vertical structure according to claim 1 or 8, wherein the carbon-containing reaction gas is CH₄ 、C₂H₂、C₂H₄Ethanol, CO₂One or more of them.

10. The method for rapidly screening the substrate of the vertical structure graphene according to claim 1, wherein the vertical structure graphene deposited in different areas in the step 4) can be deposited under the same growth condition plasma, or can be deposited under different growth conditions plasma by a micro-area multi-point mode.

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