阅读说明：本技术 一种基于单晶二维材料/单晶铜的垂直异质外延单晶金属薄膜的方法 (Method for vertical heteroepitaxy monocrystal metal film based on monocrystal two-dimensional material/monocrystal copper ) 是由 刘开辉 张智宏 王恩哥 俞大鹏 于 2019-03-07 设计创作，主要内容包括：本发明提供了一种基于单晶二维材料/单晶铜的垂直异质外延单晶金属薄膜的方法。所述单晶二维材料为单晶石墨烯或单晶氮化硼,所述方法为用单晶二维材料/单晶铜的复合结构为外延基底,在其上外延生长金属,获得单晶金属薄膜。所述金属包括但不限于金、银、铜、铂、钯、钨、铁、铬、钴、镍。本发明提出的方法,解决了单晶金属薄膜制备方法复杂、尺寸小、难剥离、价格极为昂贵的问题,通过非常简单的方法,实现了大尺寸的单晶金属薄膜的制备。(The invention provides a method for vertically heteroepitaxial monocrystal metal film based on monocrystal two-dimensional material/monocrystal copper. The method is characterized in that a single-crystal two-dimensional material is single-crystal graphene or single-crystal boron nitride, a single-crystal two-dimensional material/single-crystal copper composite structure is used as an epitaxial substrate, and metal is epitaxially grown on the epitaxial substrate to obtain a single-crystal metal film. Including, but not limited to, gold, silver, copper, platinum, palladium, tungsten, iron, chromium, cobalt, nickel. The method provided by the invention solves the problems of complex preparation method, small size, difficult stripping and extremely high price of the single crystal metal film, and realizes the preparation of the large-size single crystal metal film by a very simple method.)

1. A method for vertical heteroepitaxy of monocrystalline metal films based on monocrystalline two-dimensional material/monocrystalline copper is characterized in that monocrystalline metal films are obtained by epitaxially growing metal on a monocrystalline two-dimensional material/monocrystalline copper substrate.

2. The method according to claim 1, wherein the single-crystal two-dimensional material is single-crystal graphene or single-crystal hexagonal boron nitride, a composite structure of the single-crystal two-dimensional material and the single-crystal copper is used as an epitaxial substrate, and the crystal face index of the epitaxial single-crystal metal thin film is (111).

3. The method according to claim 2, wherein the single-crystal graphene or the single-crystal hexagonal boron nitride is grown on the surface of the single-crystal copper by a chemical vapor deposition method, and the number of layers is 1-10.

4. The method of claim 2, wherein the single crystal copper has a crystallographic index of (111) or a high crystallographic index greater than 1.

5. A method according to any of claims 1-4, characterized in that the method comprises the steps of:

s1, annealing the polycrystalline copper foil by using a chemical vapor deposition system to convert the polycrystalline copper foil into a single crystal copper foil;

s2, epitaxially growing single crystal graphene or single crystal boron nitride on the single crystal copper foil;

s3, taking the obtained single crystal graphene/single crystal copper or single crystal boron nitride/single crystal copper composite structure as a substrate, and epitaxially growing metal on the substrate to obtain a single crystal metal film, namely obtaining the single crystal metal film/single crystal two-dimensional material/single crystal copper composite structure.

6. The method according to claim 5, wherein step S1 comprises the steps of:

s11, forming one end of the polycrystalline copper foil into a tip end, flatly placing the tip end on a high-temperature-resistant substrate, placing the substrate into chemical vapor deposition equipment, introducing inert gas with the flow rate of 300-500 sccm, then starting to heat up, wherein the heating process lasts for 50-70 min, and the inert gas is N₂Or Ar;

s12, when the temperature rises to 800-1100 ℃, the polycrystalline copper foil gradually passes through the chemical vapor deposition equipment from the tip, the speed of the polycrystalline copper foil continuously passing through the heating area is 0.01-10 cm/min, the annealing process is started, and the annealing time is more than 1 min;

s13, after the annealing is finished, cooling to room temperature to obtain a large-size single crystal copper foil;

preferably, step S2 includes the steps of:

s21, placing the single crystal copper foil obtained in the step S1 into chemical vapor deposition equipment, and introducing CH₄The flow rate of the mixed gas is 0.2-50 sccm, and the growth time is 10 min-20 h;

s22, after the growth is finished, the heating power supply is turned off, and the CH is stopped being introduced₄Gas, with inert gas and H₂Naturally cooling to room temperature as protective gas, and growing high-quality oversized single crystal graphene on the surface of the copper foil;

or

S21, placing the single crystal copper foil obtained in the step S1 into chemical vapor deposition equipment, placing ammonia borane as a growth source in an upstream temperature zone, rapidly heating the upstream temperature zone to 60 ℃, and introducing inert gas and H₂The mixed gas keeps the air pressure in the system between 200Pa and 900Pa, and the growth time is 1-20 h;

s22, after the growth is finished, the heating power supply is turned off, and inert gas and H are used₂Naturally cooling to room temperature as protective gas, and growing high-quality ultra-large-size single crystal boron nitride on the surface of the copper foil;

preferably, the epitaxy method in step S3 is evaporation, and the evaporation rate isThe evaporation time is 100-.

7. The method of any of claims 1-4, wherein the method of epitaxially growing a metal includes, but is not limited to, electron beam evaporation, magnetron sputtering, thermal evaporation, atomic deposition, or electroplating.

8. The method of any of claims 1-4, wherein the metal includes, but is not limited to, gold, silver, copper, platinum, palladium, tungsten, iron, chromium, cobalt, nickel.

9. The method according to any one of claims 1 to 4, wherein the thickness of the single crystal metal thin film is 5nm to 10 μm.

10. The method according to any one of claims 1 to 4, wherein the single crystal metal thin film is supported by an adhesive flexible substrate, and the single crystal copper is removed to obtain the single crystal metal thin film.

11. A single-crystal metal thin film produced by the method according to any one of claims 1 to 10, wherein the thickness of the single-crystal metal thin film is 5nm to 10 μm.

Technical Field

The invention relates to a method for vertically heteroepitaxial monocrystal metal film based on monocrystal two-dimensional material/monocrystal copper.

Background

Metals always occupy very important positions in the historical development process of human beings, and the copper age and the ironware age which appear after the stoneware age take the application of metal materials as the remarkable signs of the ages. In the modern times, a wide variety of metals are widely used in the fields of electrical industry, light industry, machine manufacturing, building industry, national defense industry and the like, and the social progress is greatly promoted.

With the rapid development of the microelectronics industry, the preparation of metal thin films has been widely studied and has become increasingly mature. However, the existing preparation method of the metal thin film is mainly a deposition method or a sputtering method, the obtained metal thin film is mainly a polycrystalline thin film, and the existence of the grain boundary can greatly reduce the properties of the metal thin film, such as electrical properties, thermal properties, mechanical properties, corrosion resistance and the like. Although a single crystal metal thin film can be obtained by epitaxy on a single crystal substrate, its application is limited because the single crystal substrate is expensive, small in size, and difficult to be peeled off, so that the single crystal metal thin film cannot be produced on a large scale.

The single crystal copper is a very good substrate material and plays an increasingly important role in surface science, film preparation and the like. In particular, in recent years, the growth of a single-layer continuous graphene film is successfully realized on a copper foil, so that single crystal copper becomes an ideal substrate for epitaxially growing single crystal graphene and single crystal boron nitride. In patent ZL201610098623.6, the inventors annealed a commercial polycrystalline copper foil to obtain single crystal Cu (111), and then epitaxially grown single crystal graphene. The composite structure of the single crystal two-dimensional material/single crystal copper has low cost and large size, and has wide commercial prospect as a single crystal substrate.

Therefore, the single-crystal metal material can be prepared by a simple and practical method by using the single-crystal two-dimensional material/single-crystal copper composite structure as the substrate epitaxial single-crystal metal material.

Disclosure of Invention

The invention provides a method for vertically heteroepitaxially growing a single crystal metal film based on single crystal graphene/single crystal copper for the first time. Including, but not limited to, gold, silver, copper, platinum, palladium, tungsten, iron, chromium, cobalt, nickel.

A vertical heteroepitaxial single-crystal metal thin film based on single-crystal two-dimensional material/single-crystal copper is prepared by the method, the thickness of the single-crystal metal thin film is 5nm-10 mu m, and the size of the single-crystal metal thin film is 0.1-50 m. The size means that if the single crystal metal thin film is circular, the size of 0.1 to 50m means that the diameter thereof is 0.1 to 50 m; if the single crystal metal thin film is a long strip, a size of 0.1 to 50m means a length of 0.1 to 50 m.

Preferably, in the above method, the single-crystal two-dimensional material is single-crystal graphene or single-crystal hexagonal boron nitride, the composite structure of the single-crystal two-dimensional material/single-crystal copper is used as an epitaxial substrate, and the crystal plane index of the epitaxial single-crystal metal thin film is (111).

Preferably, in the above method, the single crystal graphene or boron nitride is grown on the surface of the single crystal copper by chemical vapor deposition, and the number of layers is 1 to 10.

Preferably, in the above method, the single-crystal copper has a crystal plane index of (111) or a high crystal plane index having a crystal plane index of more than 1.

Preferably, in the above method, the method comprises the steps of:

s1, annealing the polycrystalline copper foil by using a chemical vapor deposition system to convert the polycrystalline copper foil into a single crystal copper foil;

s2, epitaxially growing single crystal graphene or single crystal boron nitride on the single crystal copper foil;

s3, taking the obtained single crystal two-dimensional material/single crystal copper composite structure as a substrate, and epitaxially growing metal on the substrate to obtain a single crystal metal film, namely the single crystal metal film/single crystal graphene/single crystal copper composite structure.

Preferably, in the above method, the step S1 includes the steps of:

s11, forming one end of the polycrystalline copper foil into a tip end which is horizontally arranged on a high-temperature resistant substrate, and putting the substrate into a chemical vapor deposition deviceDuring preparation, introducing inert gas with the flow rate of 300-500 sccm, then starting to heat up, wherein the heating process lasts for 50-70 min, and the inert gas is N₂Or Ar;

s12, when the temperature rises to 800-1100 ℃, the polycrystalline copper foil gradually passes through the chemical vapor deposition equipment from the tip, the speed of the polycrystalline copper foil continuously passing through the heating area is 0.01-10 cm/min, the annealing process is started, and the annealing time is more than 1 min;

s13, after the annealing is finished, cooling to room temperature to obtain a large-size single crystal copper foil;

preferably, in the above method, the step S2 includes the steps of:

s21, placing the single crystal copper foil obtained in the step S1 into chemical vapor deposition equipment, and introducing CH₄The flow rate of the mixed gas is 0.2-50 sccm, and the growth time is 10 min-20 h;

s22, after the growth is finished, the heating power supply is turned off, and the CH is stopped being introduced₄Gas, with inert gas and H₂Naturally cooling to room temperature as protective gas, and growing high-quality oversized single crystal graphene on the surface of the copper foil;

or

S21, placing the single crystal copper foil obtained in the step S1 into chemical vapor deposition equipment, placing ammonia borane as a growth source in an upstream temperature zone, rapidly heating the upstream temperature zone to 60 ℃, introducing mixed gas of inert gas and H2, and keeping the air pressure in the system between 200Pa and 900Pa for 1-20H;

s22, after the growth is finished, turning off a heating power supply, taking inert gas and H2 as protective gas, naturally cooling to room temperature, and growing high-quality oversized single crystal boron nitride on the surface of the copper foil;

preferably, in the above method, the epitaxy method in step S3 is deposition, and the deposition rate is set toThe evaporation time is 100-.

Preferably, in the above method, the method of epitaxially growing a metal includes, but is not limited to, electron beam evaporation, magnetron sputtering, thermal evaporation, atomic deposition, or electroplating.

Preferably, in the above method, the metal includes, but is not limited to, gold, silver, copper, platinum, palladium, tungsten, iron, chromium, cobalt, nickel.

Preferably, in the above method, the thickness of the single crystal metal thin film is 5nm to 10 μm.

Preferably, in the above method, the single crystal metal thin film is supported by a flexible substrate having adhesiveness, and the single crystal copper is removed to obtain the single crystal metal thin film.

The invention provides a monocrystalline metal film, which is prepared by the method and has the thickness of 5nm-10 mu m.

The invention uses the composite structure of single crystal two-dimensional material/single crystal copper as the substrate and uses the vertical heteroepitaxial growth method to prepare the single crystal metal film. The method provided by the invention solves the problems of complex preparation method, small size, difficult stripping and extremely high price of the monocrystalline metal film, and realizes the preparation of the monocrystalline metal film with high quality and large size by a very simple method.

The invention has the advantages that:

1. the invention firstly proposes that a single-crystal two-dimensional material/single-crystal copper composite structure is used as a substrate, and the preparation of a single-crystal metal film is realized by utilizing vertical heteroepitaxial growth;

2. the epitaxial substrate selected by the invention is a monocrystalline copper foil obtained by annealing commercially available polycrystalline copper foil, and then monocrystalline graphene or monocrystalline boron nitride is grown on the monocrystalline copper foil by using a chemical vapor deposition method, so that the obtained monocrystalline two-dimensional material/monocrystalline copper substrate has low cost and large size;

3. the invention can prepare various single crystal metal films of gold, silver, copper, platinum, palladium, tungsten, iron, chromium, cobalt, nickel and the like;

4. in the invention, the single crystal copper can be removed by supporting the single crystal metal thin film with a flexible substrate having adhesiveness, and the single crystal metal thin film can be obtained without the problem that the metal thin film is difficult to peel.

5. The method can realize the preparation of the large-size monocrystalline metal film and is beneficial to promoting the industrial production of the practical application of the monocrystalline metal film.

Drawings

FIG. 1 shows the results of X-ray diffraction (XRD) of electron beam evaporation of palladium with a thickness of 100nm on single-crystal graphene/single-crystal copper.

Fig. 2 is a photograph of a 6 inch single crystal palladium thin film.

FIG. 3 shows the X-ray diffraction (XRD) results of thermal deposition of 400nm thick gold on single-crystal graphene/single-crystal copper.

FIG. 4 is a 300nm SiO₂X-ray diffraction (XRD) results of electron beam evaporation of Pd having a thickness of 100nm on a/Si substrate.

Detailed Description

The present invention is further described in detail below with reference to specific examples, which are commercially available from the public unless otherwise specified. The examples are given solely for the purpose of illustration and are not intended to limit the scope of the invention