CN106587030B - A kind of method that atmospheric cryochemistry vapor deposition prepares graphene film - Google Patents

Abstract

The invention discloses a method for preparing a graphene film by atmospheric pressure low-temperature chemical vapor deposition. In the method, a metal substrate is firstly subjected to high-temperature annealing treatment, and then the temperature-lowering annealing treatment is performed, and then graphite is obtained on the surface of the metal substrate through a chemical vapor deposition method. vinyl film. The method of the present invention improves the catalytic activity of the metal substrate, thereby reducing the growth temperature of graphene, thus reducing the energy consumption and cost of industrial production of graphene films. Compared with the traditional chemical vapor deposition method for synthesizing graphene films, the method of the present invention The process is simple, the sources of carbon sources are extensive, and the prepared graphene film has high quality, uniform and controllable layers.

Description

A method for preparing graphene film by atmospheric pressure low temperature chemical vapor deposition

technical field

The invention relates to the field of graphene preparation, in particular to a method for preparing a graphene film at normal pressure and low temperature by chemical vapor deposition.

Background technique

Graphene is a hexagonal honeycomb two-dimensional crystal composed of a single layer of carbon atoms based on ^sp2 hybridization. Since it was discovered by Andre Geim and Konstantin Novoselov in 2004, it has attracted extensive attention from the scientific community. The excellent properties of graphene in electricity, optics, heat, mechanics, etc. make it have great potential application prospects in the fields of batteries, flexible transparent electrodes, energy storage materials, electrocatalysts, nanoelectronic devices, and composite materials.

At present, the preparation methods of graphene films mainly include: mechanical exfoliation method, reduced graphite oxide method, chemical vapor deposition (CVD), epitaxial growth method and so on. Among them, although the mechanical exfoliation method can produce graphene with excellent performance, the efficiency is low and the repeatability is poor; the reduced graphite oxide method can prepare graphene in large quantities, but its quality is very poor; the cost of graphene prepared by the SiC epitaxial growth method is high. . In contrast, the chemical vapor deposition method is simple to operate, and can prepare large-area graphene with uniform layers. Especially, the gaseous carbon source can be continuously supplied, which is an effective way to realize the continuous and industrial production of graphene. However, the existing CVD method for growing graphene must be carried out at high temperature (usually higher than 1000°C), which greatly hinders the industrial production of graphene. Therefore, finding a method to prepare graphene with a controllable layer number at low temperature is very important for the large-scale production and application of graphene.

Contents of the invention

The invention mainly aims at the problem that graphene must be prepared at high temperature by the existing chemical vapor deposition method, and provides a method for preparing graphene film at normal pressure and low temperature by using the chemical vapor deposition method.

To achieve the above object, the present invention adopts the following technical solutions:

A method for preparing a graphene film by atmospheric pressure low-temperature chemical vapor deposition, comprising the steps of:

(1) Clean the metal substrate with hydrochloric acid, acetone, and deionized water ultrasonically for 5-10 minutes, and remove the moisture on the surface of the metal substrate, and then perform high-temperature annealing treatment on the metal substrate. The flow rate is 10~100sccm, the temperature is 850~1050℃, and the processing time is 10~90min;

(2) Perform cooling annealing treatment on the metal substrate that has been subjected to high-temperature annealing treatment in step (1), the treatment conditions are: uniformly cool down to 200-800° C. in an argon atmosphere, and the argon flow rate is 300-1000 sccm;

(3) After the metal substrate in step (2) drops to the predetermined reaction temperature, gas carbon source and argon gas are introduced, and chemical vapor deposition is carried out to obtain a graphene film.

Preferably, the metal substrate is at least one of copper foil, cobalt foil, nickel foil, and iron foil, or at least one of copper film, cobalt film, nickel film, and iron film. The metal substrate used in the present invention can be prepared by existing metal film preparation methods, such as magnetron sputtering, electrochemical deposition, vacuum evaporation and other methods.

Preferably, the high-temperature annealing treatment conditions in step (1) are: argon gas flow rate 800 sccm, hydrogen gas flow rate 30 sccm, temperature 950° C., and treatment time 50 min.

Preferably, the metal substrate is copper foil.

Preferably, the cooling rate in step (2) is 1-30° C./min.

Preferably, in the step (2), the temperature of the metal substrate is lowered to 300-700° C. at a uniform speed. In the present invention, when the temperature-lowering annealing treatment is performed in step (2), the metal substrate subjected to the high-temperature annealing treatment may also be cooled to room temperature at a uniform speed in an argon atmosphere, and then raised to a predetermined reaction temperature.

Preferably, the gaseous carbon source in step (3) is at least one of methane, ethane, acetylene, ethylene, and propane.

Preferably, the chemical vapor deposition conditions in step (3) are: carbon source gas flow rate 1-10 sccm, argon gas flow rate 100-1000 sccm, and reaction time 1-20 min.

Preferably, the gaseous carbon source is methane.

Compared with the prior art, the present invention has the following beneficial effects:

1. The present invention reduces the adsorption energy and dehydrogenation cracking energy of gaseous hydrocarbons on the surface of the metal substrate by first performing high-temperature annealing treatment on the metal substrate, and then performing the cooling annealing treatment, improves the catalytic ability of the metal substrate itself, and obtains The metal substrate with high catalytic activity greatly reduces the growth temperature of graphene, thus reducing the energy consumption and cost of industrial production of graphene film, which is beneficial to the industrialization process of graphene.

2. The present invention realizes the preparation of single-layer continuous graphene film by chemical vapor deposition method under normal pressure and low temperature. The Raman scattering of the prepared graphene film has obvious 2D peak, and I _G /I _2D <0.5, and the light transmittance is 97.1~97.3%, compared with the traditional chemical vapor deposition method for synthesizing graphene films, the method of the present invention has simple process, wide range of carbon sources, and the prepared graphene films have high quality, uniform and controllable layers.

Description of drawings

Fig. 1 is the experimental device structural representation that the present invention prepares graphene film to adopt;

Fig. 2 is the optical micrograph of the graphene thin film that embodiment 1 prepares;

Fig. 3 is the Raman spectrogram of the graphene thin film that embodiment 1 prepares;

Fig. 4 is the scanning electron micrograph of the graphene thin film that embodiment 1 prepares;

Fig. 5 is the optical micrograph of the graphene thin film that embodiment 2 prepares;

Fig. 6 is the Raman spectrogram of the graphene thin film that embodiment 2 prepares;

Fig. 7 is the transmission electron micrograph of the graphene thin film prepared in embodiment 2.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is the schematic diagram of the experimental device structure that the present invention prepares graphene film to adopt, and as shown in Fig. 1, this device comprises argon gas source 1, hydrogen gas source 2, gas carbon source 3, gas flow control system and gas mixing system 4 , quartz tube 5 and CVD tube furnace 6. When adopting this device to prepare a graphene film, the metal substrate 7 is first placed in the quartz tube 5, and the metal substrate 7 is placed in the middle of the tube furnace 6. After the metal substrate 7 is annealed twice, the gas carbon source 3 and argon into the quartz tube 5 for chemical vapor deposition, and a graphene film can be obtained on the surface of the metal substrate 7 .

Example 1

In this embodiment, a graphene film is prepared by chemical deposition at normal pressure and low temperature, including the following steps:

(1) Ultrasonic clean the copper foil with hydrochloric acid, acetone and deionized water for 5~10 minutes, then remove the moisture on the surface of the copper foil, then put the copper foil into the quartz tube, and make the copper foil in the middle of the tube furnace, adjust The flow rate of argon gas is 800 sccm, and the flow rate of hydrogen gas is 30 sccm. In this atmosphere, the copper foil is heated to 950°C, and then annealed for 50 minutes;

(2) Cool the annealed copper foil in step (1) to 700°C at a constant speed in an argon atmosphere, where the flow rate of argon gas is 300 sccm, and the cooling rate is 28°C/min;

(3) When the temperature of the copper foil in step (2) drops to 700°C, feed methane and argon to grow graphene, wherein the flow rate of methane is 2 sccm, the flow rate of argon gas is 500 sccm, and the reaction time is 5 minutes;

(4) After 5 minutes of reaction, stop feeding methane, and quickly lower the copper foil to room temperature, and a graphene film can be obtained on the surface of the copper foil.

Fig. 2 is an optical microscope picture of the graphene film prepared in this embodiment transferred onto a SiO ₂ /Si substrate. It can be seen from Fig. 2 that the thickness of the graphene film prepared in this embodiment is uniform.

Fig. 3 is the Raman spectrum of the graphene film prepared by the present embodiment, as shown in Fig. 3, the characteristic peak 2D peak of the graphene film prepared by the present embodiment is very obvious, and the ratio of 2D peak and G peak is greater than 2, simultaneously There is also an obvious defect peak D peak, which proves that a relatively high-quality single-layer graphene is prepared in this embodiment.

Figure 4 is a scanning electron microscope picture of the graphene film prepared in this example transferred to a SiO ₂ /Si substrate. On the left side of the picture, the boundary of graphene can be clearly seen, and no cracks are seen in the figure, which proves the preparation of this example. Graphene is continuous.

Example 2

In this embodiment, a graphene film is prepared by chemical deposition at normal pressure and low temperature, including the following steps:

(1) Ultrasonic clean the copper foil with hydrochloric acid, acetone and deionized water for 5~10 minutes, then remove the moisture on the surface of the copper foil, then put the copper foil into the quartz tube, and make the copper foil in the middle of the tube furnace, adjust The flow rate of argon gas is 800 sccm, and the flow rate of hydrogen gas is 30 sccm. In this atmosphere, the copper foil is heated to 950°C, and then annealed for 50 minutes;

(2) Cool the annealed copper foil in step (1) to 400°C at a constant rate in an argon atmosphere, where the argon flow rate is 300 sccm, and the cooling rate is 30°C/min;

(3) When the temperature of the copper foil in step (2) drops to 400°C, feed methane and argon to grow graphene, wherein the flow rate of methane is 10 sccm, the flow rate of argon gas is 500 sccm, and the reaction time is 10 min;

(4) After 10 minutes of reaction, stop feeding methane, and quickly lower the copper foil to room temperature, and a graphene film can be obtained on the surface of the copper foil.

Fig. 5 is the graphene film that the present embodiment makes is transferred to the optical microscope picture on SiO ₂ /Si substrate, as can be seen from Fig. 2, the graphene film thickness that the present embodiment prepares is uniform, can clearly see from the rupture To the boundary of SiO ₂ /Si substrate and graphene.

Fig. 6 is the Raman spectrum of the graphene thin film prepared by the present embodiment, as shown in Fig. 3, the characteristic peak 2D peak of the graphene thin film prepared by the present embodiment is very obvious, and the ratio of 2D peak and G peak is close to 2, relatively Compared with Example 1, the defect peak D peak of the graphene film prepared in this example decreases, indicating that the quality of graphene prepared in this example is slightly higher than that of Example.

Figure 7 is a transmission electron microscope picture of the graphene film prepared in this embodiment transferred to a copper grid, and it can be clearly seen from Figure 7 that the graphene prepared in this embodiment is a single-layer graphene.

Example 3

In this embodiment, a graphene film is prepared by chemical deposition at normal pressure and low temperature, including the following steps:

(1) Prepare a copper-nickel alloy film on a SiO ₂ /Si sheet by magnetron sputtering, then put the copper-nickel alloy film into a quartz tube, and place the copper-nickel alloy film in the middle of the tube furnace, and adjust the argon flow to 900sccm, the hydrogen flow rate is 30sccm, the copper-nickel alloy film is heated to 900°C in this atmosphere, and then annealed for 65min;

(2) The annealed copper-nickel alloy film in step (1) is cooled to 400°C at a uniform speed in an argon atmosphere, wherein the argon gas flow rate is 400 sccm, and the cooling rate is 25°C/min;

(3) When the temperature of the copper-nickel alloy film in step (2) drops to 400°C, feed the mixed gas of acetylene and argon to grow graphene, wherein the flow rate of the mixed gas is 10 sccm, and the volume ratio of acetylene in the mixed gas is 1:2, the argon flow rate is 600sccm, and the reaction time is 15min;

(4) After reacting for 15 minutes, stop feeding the mixed gas, and quickly lower the copper-nickel alloy film to room temperature, and a graphene film can be obtained on the surface of the copper-nickel alloy film.

Example 4

In this embodiment, a graphene film is prepared by chemical deposition at normal pressure and low temperature, including the following steps:

(1) Ultrasonic clean the copper-iron alloy foil with hydrochloric acid, acetone and deionized water for 5-10 minutes, then remove the moisture on the surface of the copper-iron alloy foil, then put the copper-iron alloy foil into the quartz tube, and make the copper-iron alloy foil in the tube type In the middle of the furnace, adjust the flow rate of argon gas to 300 sccm, and the flow rate of hydrogen gas to 15 sccm, heat the copper foil to 850°C in this atmosphere, and then anneal for 10 minutes;

(2) Cool the copper-iron alloy foil annealed in step (1) to 300°C at a uniform rate in an argon atmosphere, wherein the flow rate of argon gas is 600 sccm, and the cooling rate is 3°C/min;

(3) When the temperature of the copper foil in step (2) drops to 300°C, feed acetylene and argon to grow graphene, wherein the flow rate of acetylene is 5 sccm, the flow rate of argon gas is 1000 sccm, and the reaction time is 20 minutes;

(4) After reacting for 20 minutes, stop feeding methane, and quickly lower the copper-iron alloy foil to room temperature, and a graphene film can be obtained on the surface of the copper-iron alloy foil.

Example 5

In this embodiment, a graphene film is prepared by chemical deposition at normal pressure and low temperature, including the following steps:

(1) Clean the copper film with hydrochloric acid, acetone and deionized water ultrasonically for 5-10 minutes, then remove the moisture on the surface of the copper film, then put the copper film into the quartz tube, and make the copper film in the middle of the tube furnace, adjust The flow rate of argon gas is 500 sccm, and the flow rate of hydrogen gas is 90 sccm. In this atmosphere, the copper foil is heated to 1050°C, and then annealed for 90 minutes;

(2) Cool the annealed copper film in step (1) to 800°C at a constant speed in an argon atmosphere, wherein the argon flow rate is 1000 sccm, and the cooling rate is 15°C/min;

(3) When the temperature of the copper foil in step (2) drops to 800°C, feed ethylene and argon to grow graphene, wherein the flow rate of ethylene is 8 sccm, the flow rate of argon gas is 100 sccm, and the reaction time is 1 min;

(4) After reacting for 1 min, stop feeding methane, and quickly lower the copper film to room temperature, and a graphene film can be obtained on the surface of the copper film.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall be covered by the claims of the present invention.

Claims (6)

1. a method for preparing graphene film by atmospheric pressure low-temperature chemical vapor deposition, is characterized in that, comprises the steps: (1) Clean the metal substrate with hydrochloric acid, acetone, and deionized water ultrasonically for 5-10 minutes, and remove the moisture on the surface of the metal substrate, and then perform high-temperature annealing treatment on the metal substrate. The flow rate is 10~100sccm, the temperature is 850~950℃, and the processing time is 10~90min; the metal substrate is at least one of copper foil, cobalt foil, nickel foil, iron foil, or copper film, cobalt film, nickel film , at least one of the iron film; (2) Perform cooling annealing treatment on the metal substrate that has been subjected to high-temperature annealing treatment in step (1), the treatment conditions are: uniformly cool down to 200-800° C. in an argon atmosphere, and the argon flow rate is 300-1000 sccm; (3) After the metal substrate in step (2) drops to the predetermined reaction temperature, gas carbon source and argon gas are introduced, and chemical vapor deposition is carried out to obtain a graphene film. The gas carbon source is methane, ethane, acetylene, At least one of ethylene and propane, the chemical vapor deposition conditions are: the carbon source gas flow rate is 1-10 sccm, the argon gas flow rate is 100-1000 sccm, and the reaction time is 1-10 min. 2. The method for preparing a graphene film by atmospheric pressure low-temperature chemical vapor deposition according to claim 1, wherein the high-temperature annealing treatment conditions in step (1) are: argon gas flow rate 800 sccm, hydrogen gas flow rate 30 sccm, temperature 950 ° C, The processing time is 50min. 3. the method for preparing graphene film by atmospheric pressure low-temperature chemical vapor deposition according to claim 1, is characterized in that, described metal substrate is copper foil. 4. The method for preparing graphene film by atmospheric pressure low temperature chemical vapor deposition according to claim 1, characterized in that the cooling rate in step (2) is 1-30°C/min. 5. The method for preparing a graphene film by atmospheric pressure and low temperature chemical vapor deposition according to claim 1, characterized in that in step (2), the metal substrate is cooled to 300-700°C at a uniform speed. 6. the method for preparing graphene thin film by atmospheric pressure low-temperature chemical vapor deposition according to claim 1, is characterized in that, described gaseous carbon source is methane.