1. A graphene transfer method based on a metallic silver sacrificial layer is characterized by comprising the following steps:

growing graphene on a metal substrate by adopting a chemical vapor deposition method to obtain a first sample sheet;

uniformly depositing silver on the graphene to obtain a second sample wafer;

spinning and coating polymethyl methacrylate on the second sample wafer to obtain a third sample wafer;

etching the metal substrate in the third sample wafer by using an etching solution to obtain a fourth sample wafer;

transferring the fourth sample wafer to a target substrate to obtain a fifth sample wafer;

and removing the polymethyl methacrylate in the fifth sample wafer, and etching the silver.

2. The method for transferring graphene based on a metallic silver sacrificial layer according to claim 1, wherein in the step of growing graphene on a metal substrate by using a chemical vapor deposition method:

the metal substrate is copper, nickel, platinum, cobalt, iron, molybdenum, ruthenium or iridium, and the graphene is single-layer graphene, double-layer graphene or multi-layer graphene.

3. The method of claim 1, wherein the step of uniformly depositing silver on the graphene to obtain the second sample comprises:

washing the first glass culture dish and the second glass culture dish by hot alkali;

washing the first glass culture dish and the second glass culture dish by using deionized water;

drying the first glass culture dish and the second glass culture dish by using a nitrogen gun;

fixing the first sample sheet in the second glass culture dish, and putting the first sample sheet and the second sample sheet into the first glass culture dish;

15-30 ml of 5% silver ammonia solution is poured into the second glass culture dish;

pouring 5-10 ml of 17% glucose solution into the silver ammonia solution, and uniformly mixing;

placing the first glass culture dish on a heating table;

adding a proper amount of water into the first glass culture dish, and setting the temperature of a heating table to be 65-75 ℃;

and heating the first glass culture dish in a water bath to obtain the second sample wafer.

4. The method for transferring graphene based on a metallic silver sacrificial layer according to claim 1, wherein in the step of spin-coating polymethyl methacrylate on the second sample:

the thickness of the spin-coated polymethyl methacrylate is 1.5-2.7 um.

5. The method for transferring graphene based on metallic silver sacrificial layer according to claim 1, wherein the step of etching away the metal substrate in the third sample wafer with an etching solution comprises:

the concentration of the etching liquid is 0.5-1 mol/L, and the etching liquid is an ammonium persulfate solution, a ferric nitrate solution or a ferric chloride solution.

6. The method for transferring graphene based on a metallic silver sacrificial layer according to claim 1, wherein in the step of transferring the fourth sample onto a target substrate:

the target substrate is a silicon wafer, a silicon oxide wafer, sapphire, a glass sheet or ceramic.

7. The method for transferring graphene based on a metallic silver sacrificial layer according to claim 1, wherein the step of removing the polymethyl methacrylate in the fifth sample and etching the silver comprises:

and removing the polymethyl methacrylate in the fifth sample wafer by using acetone, and etching the silver in the fifth sample wafer by using nitric acid, thereby completing the transfer of the graphene.

Background

Chemical Vapor Deposition (CVD) is currently the most effective method for obtaining large-area high-quality graphene in the industry. The CVD method generally uses a transition metal foil such as platinum, cobalt, nickel, copper, or iron as a base material. Thus, when using graphene, it is necessary to transfer the graphite to a target substrate.

At present, there are many graphene transfer techniques, wherein the wet transfer mainly uses an etching solution to etch away a metal substrate, and this transfer method needs the assistance of a support film to complete the transfer of graphene, wherein the most common support film is polymethyl methacrylate. In the transfer process, the polymethyl methacrylate directly contacts the graphene, so that the graphene is difficult to remove, and the graphene is changed into heavy P-type doping, so that the application of the graphene is influenced.

Disclosure of Invention

The invention aims to provide a graphene transfer method based on a metallic silver sacrificial layer, and aims to solve the technical problems that polymethyl methacrylate is difficult to remove and graphene is changed into heavy P type doping in the prior art.

In order to achieve the above purpose, the graphene transfer method based on the metallic silver sacrificial layer adopted by the invention comprises the following steps:

growing graphene on a metal substrate by adopting a chemical vapor deposition method to obtain a first sample sheet;

uniformly depositing silver on the graphene to obtain a second sample wafer;

spinning and coating polymethyl methacrylate on the second sample wafer to obtain a third sample wafer;

etching the metal substrate in the third sample wafer by using an etching solution to obtain a fourth sample wafer;

transferring the fourth sample wafer to a target substrate to obtain a fifth sample wafer;

and removing the polymethyl methacrylate in the fifth sample wafer, and etching the silver.

The method comprises the following steps of growing graphene on a metal substrate by adopting a chemical vapor deposition method:

the metal substrate is copper, nickel, platinum, cobalt, iron, molybdenum, ruthenium or iridium, and the graphene is single-layer graphene, double-layer graphene or multi-layer graphene.

Wherein, the step of uniformly depositing silver on the graphene to obtain a second sample wafer comprises:

washing the first glass culture dish and the second glass culture dish by hot alkali;

washing the first glass culture dish and the second glass culture dish by using deionized water;

drying the first glass culture dish and the second glass culture dish by using a nitrogen gun;

fixing the first sample sheet in the second glass culture dish, and putting the first sample sheet and the second sample sheet into the first glass culture dish;

15-30 ml of 5% silver ammonia solution is poured into the second glass culture dish;

pouring 5-10 ml of 17% glucose solution into the silver ammonia solution, and uniformly mixing;

placing the first glass culture dish on a heating table;

adding a proper amount of water into the first glass culture dish, and setting the temperature of a heating table to be 65-75 ℃;

and heating the first glass culture dish in a water bath to obtain the second sample wafer.

Wherein, in the step of spin-coating polymethyl methacrylate on the second sample:

the thickness of the spin-coated polymethyl methacrylate is 1.5-2.7 um.

Wherein, the step of etching away the metal substrate in the third sample wafer with an etching solution comprises:

the concentration of the etching liquid is 0.5-1 mol/L, and the etching liquid is an ammonium persulfate solution, a ferric nitrate solution or a ferric chloride solution.

Wherein, in the step of transferring the fourth swatch to a target substrate:

the target substrate is a silicon wafer, a silicon oxide wafer, sapphire, a glass sheet or ceramic.

Removing the polymethyl methacrylate in the fifth sample wafer, and etching the silver:

and removing the polymethyl methacrylate in the fifth sample wafer by using acetone, and etching the silver in the fifth sample wafer by using nitric acid, thereby completing the transfer of the graphene.

The invention has the beneficial effects that: a layer of metal silver is deposited on the surface of the graphene, so that the direct contact between the graphene and the polymethyl methacrylate is avoided, and the graphene is prevented from being in a heavy P-doped state. Organic matter residues introduced in the graphene transfer process are avoided. The metallic silver can completely unfold the graphene, so that the graphene is convenient to transfer to a target substrate. Silver generated by the reaction of the silver ammonia solution and glucose is uniformly deposited on the surface of the graphene, so that the graphene is prevented from being polluted in the transfer process.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a flow chart of the steps of the inventive graphene transfer method based on a metallic silver sacrificial layer.

Fig. 2 is a structural view of a first sample of the present invention.

Fig. 3 is a structural view of a second sample of the present invention.

Fig. 4 is a structural view of a third sample of the present invention.

Fig. 5 is a structural view of a fourth sample of the present invention.

Fig. 6 is a structural view of a fifth sample of the present invention.

FIG. 7 is a structural diagram of a fifth coupon of the present invention after washing away the PMMA and silver.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the invention and are not to be construed as limiting the invention.

In the description of the present invention, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, indicate orientations or positional relationships based on the orientations or positional relationships illustrated in the drawings, and are used merely for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention. Further, in the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

Referring to fig. 1 to 7, the present invention provides a graphene transfer method based on a metallic silver sacrificial layer, including the following steps:

s1, growing graphene on the metal substrate by adopting a chemical vapor deposition method to obtain a first sample sheet;

s2, uniformly depositing silver on the graphene to obtain a second sample wafer;

s3, spinning and coating polymethyl methacrylate on the second sample to obtain a third sample;

s4, etching the metal substrate in the third sample wafer by using etching liquid to obtain a fourth sample wafer;

s5, transferring the fourth sample wafer to a target substrate to obtain a fifth sample wafer;

and S6, removing the polymethyl methacrylate in the fifth sample wafer and etching the silver.

Specifically, the step of growing graphene on a metal substrate by using a chemical vapor deposition method comprises:

the metal substrate is copper, nickel, platinum, cobalt, iron, molybdenum, ruthenium or iridium, and the graphene is single-layer graphene, double-layer graphene or multi-layer graphene.

Specifically, the step of uniformly depositing silver on the graphene to obtain a second sample wafer includes:

washing the first glass culture dish and the second glass culture dish by hot alkali;

washing the first glass culture dish and the second glass culture dish by using deionized water;

drying the first glass culture dish and the second glass culture dish by using a nitrogen gun;

fixing the first sample sheet in the second glass culture dish, and putting the first sample sheet and the second sample sheet into the first glass culture dish;

15-30 ml of 5% silver ammonia solution is poured into the second glass culture dish;

pouring 5-10 ml of 17% glucose solution into the silver ammonia solution, and uniformly mixing;

placing the first glass culture dish on a heating table;

adding a proper amount of water into the first glass culture dish, and setting the temperature of a heating table to be 65-75 ℃;

and heating the first glass culture dish in a water bath to obtain the second sample wafer.

Specifically, in the step of spin-coating polymethyl methacrylate on the second sample:

the degree of the spin-coated polymethyl methacrylate is 1.5-2.7 um.

Specifically, in the step of etching away the metal substrate in the third sample wafer with an etching solution:

the concentration of the etching liquid is 0.5-1 mol/L, and the etching liquid is an ammonium persulfate solution, a ferric nitrate solution or a ferric chloride solution.

Specifically, in the step of transferring the fourth sample onto the target substrate:

the target substrate is a silicon wafer, a silicon oxide wafer, sapphire, a glass sheet or ceramic.

Specifically, the step of removing the polymethylmethacrylate in the fifth sample wafer and etching the silver comprises:

and removing the polymethyl methacrylate in the fifth sample wafer by using acetone, and etching the silver in the fifth sample wafer by using nitric acid, thereby completing the transfer of the graphene.

Compared with the traditional wet etching method, the graphene subjected to the traditional wet etching method is in a heavy P-doped state due to the fact that the graphene is directly contacted with the polymethyl methacrylate, and a layer of metal silver is deposited on the surface of the graphene, so that the situation is avoided.

Polymethyl methacrylate in the traditional wet etching is extremely difficult to remove, and the polymethyl methacrylate residue still exists although the polymethyl methacrylate is repeatedly soaked in acetone for many times, and under a microscope, the polymethyl methacrylate residue is still visible.

In traditional etching process, because the sculpture of metal substrate, flexible polymethyl methacrylate can't expand completely in the etching solution, shifts to target substrate in-process, causes the fold of graphite alkene, and then causes the waste of graphite alkene, will make graphite alkene completely expand when having one deck metal sacrificial layer, and the graphite alkene of being convenient for shifts to target substrate.

The application of the metal sacrificial layer benefits from the reaction of silver ammonia solution and glucose, and the generated silver is uniformly deposited on the surface of the graphene, so that the graphene is prevented from being polluted in the transfer process.