CN104562005A - Method for controlling nucleation density of graphene growing on surface - Google Patents

Abstract

The invention provides a method for controlling the nucleation density of graphene grown on its surface, which is characterized in that it comprises the following steps: preparing hydrogen peroxide with a mass concentration of 5-30%; soaking copper foil in it, and the copper foil is oxidized by hydrogen peroxide ; Then use the pretreated copper foil for CVD growth graphene. The soaking time in the step 2) is 5-60s. Compared with other methods for controlling the nucleation density of graphene on the surface of copper foil, this method is simple and easy to implement. It only needs to soak the copper foil in hydrogen peroxide in advance to effectively reduce the nucleation density of graphene on the surface of copper foil. At the same time, this method can also be used in combination with other control methods. On the basis of this method, by controlling the gas mixture ratio, gas pressure, copper foil surface roughness, growth temperature, etc., the nucleation density can be further reduced and the graphene film can be improved. single crystal size.

Description

A method of controlling the nucleation density of graphene grown on its surface

technical field

The invention relates to a method for controlling the nucleation density of graphene grown on its surface, which belongs to the field of material technology.

Background technique

Graphene has excellent electrical, mechanical, optical, and thermal properties, and has broad prospects in the fields of electrical devices, optoelectronic devices, and heat dissipation devices. The large-scale and high-quality preparation of graphene is the prerequisite for its wide application.

The chemical vapor deposition (CVD) method is the most promising means to realize the industrial production of graphene film. Its reaction principle is: copper catalyzes the decomposition of carbon source gas, and carbon atoms form several nucleation centers on the surface of copper foil, and the final grain length Great conjunctive film. The quality of graphene largely depends on its single crystal size, that is, the nucleation density. Researchers have been trying various ways to grow graphene films with large single crystal size. While ensuring the growth rate, increasing the single crystal size of graphene, that is, reducing its nucleation density, is of great significance for improving the quality of graphene and promoting the application of graphene.

At present, methods for controlling the nucleation density of graphene on the surface of copper foil include controlling the gas mixture ratio of methane and hydrogen, gas pressure, roughness of copper foil surface, growth temperature, and introducing oxygen oxidation at high temperature to reduce the surface active sites of copper foil. The methods proposed above, especially the method of reducing the active sites on the surface of copper foil by feeding oxygen at high temperature, have very strict requirements on experimental conditions and do not use industrial production.

Contents of the invention

Technical problem: In order to control the method for the nucleation density of graphene grown on its surface, to solve the problems of complex process and low growth rate in existing methods, the invention provides a method for controlling the nucleation density of graphene grown on its surface method.

Technical scheme: the method for the nucleation density of the graphene of its surface growth of the present invention's control, comprises the steps:

1) Prepare hydrogen peroxide with a mass concentration of 5-30%;

2) Soak the copper foil in it, and the copper foil is oxidized by hydrogen peroxide;

3) Then use the pretreated copper foil for CVD growth of graphene.

The soaking time in the step 2) is 5-60s.

Preferably,

The mass concentration of hydrogen peroxide in the step 1) is 5%.

The soaking time in the step 2) is 30s.

The CVD growth graphene method in step 3) is as follows: the hydrogen peroxide pretreated copper foil and the unpretreated copper foil are placed in the growth furnace in parallel, the methane and hydrogen flow rates are controlled to be 20 and 100 sccm respectively, and the mixing pressure is 200pa, growth temperature 1045℃, growth time 1 minute.

The principle of the method for controlling the nucleation density of graphene grown on the surface of the present invention is as follows: the impurity activity on the surface of the copper foil is relatively strong, and it is the easy nucleation site of graphene. Hydrogen peroxide pretreatment oxidizes the surface of copper foil, and the oxygen on the surface of copper foil chemically reacts with surface impurities at high temperature, thereby reducing the density of active centers on the surface of copper foil and reducing the nucleation density of graphene.

Beneficial effects: Compared with other methods for controlling the nucleation density of graphene on the surface of copper foil, this method is simple and easy to implement. It only needs to soak the copper foil in hydrogen peroxide in advance to effectively reduce the nucleation density of graphene on the surface of copper foil. At the same time, this method can also be used in combination with other control methods. On the basis of this method, by controlling the gas mixture ratio, gas pressure, copper foil surface roughness, growth temperature, etc., the nucleation density can be further reduced and the graphene film can be improved. single crystal size.

Description of drawings

Figure 1 is a 500x optical microscope picture of the nucleation distribution of single-layer graphene on the surface of copper foil without hydrogen peroxide pretreatment (the bright color area is single-layer graphene).

Figure 2 is a 500x optical microscope image of the single-layer graphene nucleation distribution on the copper foil surface pretreated with 5% hydrogen peroxide for 30 seconds (the bright color area is the single-layer graphene).

specific embodiment

Example 1

The method for the nucleation density of the graphene of its surface growth of the present invention's control, comprises the steps:

1) Prepare a concentration of 5% hydrogen peroxide solution;

2) Obtain a piece of copper foil with a thickness of 25 microns and treat it in 5% hydrogen peroxide for 30 seconds;

3) CVD growth of graphene: Place the copper foil pretreated with hydrogen peroxide and the copper foil without pretreatment in parallel in the growth furnace, control the flow of methane and hydrogen to 20 and 100 sccm respectively, the mixing pressure to 200pa, and the growth temperature to 1045°C. Growth time 1 minute;

 The grown copper foil was treated with hydrogen peroxide for a few minutes, and then the nucleation density of graphene on the surface of the copper foil was observed using an optical microscope. Figure 1 is a 500x optical microscope picture of the nucleation distribution of graphene on the surface of copper foil without hydrogen peroxide pretreatment (the bright color area is graphene). Figure 2 is a 500x optical microscope picture of the nucleation distribution of single-layer graphene on the surface of copper foil pretreated with 5% hydrogen peroxide for 30 seconds (the bright area is graphene). It can be seen that pre-soaking the copper foil in hydrogen peroxide can effectively reduce the nucleation density of graphene on the surface of the copper foil.

Claims (4)

1. control a method for the Enhancing Nucleation Density of its epontic Graphene, it is characterized in that, comprise the steps:

1) preparing mass concentration is the hydrogen peroxide of 5-30%;

2) soaked wherein by Copper Foil, Copper Foil is by hydrogen peroxide oxidation;

3) then CVD growing graphene is used for this pretreated Copper Foil,

Described step 2) in soak time be 5-60s.

2. method according to claim 1, is characterized in that, the hydrogen peroxide mass concentration in described step 1) is 5%.

3. method according to claim 1, is characterized in that, described step 2) in soak time be 30s.

4. method according to claim 1, it is characterized in that, the CVD growing graphene method of described step 3) is as follows: by Copper Foil pretreated for hydrogen peroxide with do not carry out pretreated Copper Foil and be placed in parallel in growth furnace, control methane, hydrogen flow and be respectively 20 and 100sccm, mixing pressure is 200pa, growth temperature 1045 DEG C, growth time 1 minute.