A method for preparing an atomic multinary metal oxide film by laser ablation of a liquid metal and an atomic multinary metal oxide film

Abstract

The application provides a method for preparing an atomic multinary metal oxide film by laser ablation of liquid metal and the atomic multinary metal oxide film, and relates to the technical field of two-dimensional atomic films. The method comprises the following steps: applying liquid metal to a carrier, placing the carrier in a container, and performing liquid sealing on the liquid metal by using a metal precursor salt solution; performing laser ablation treatment on the liquid metal in liquid sealing, so that a metal oxide film is formed on the surface of the liquid metal; and transferring the metal oxide film from the surface layer of the liquid metal to a substrate by using van der Waals transfer technology. The present application does not need to consider the lattice matching of the substrate and the material, greatly simplifies the preparation steps of the two-dimensional multinary metal oxide film, and realizes the synthesis of the atomic multinary metal oxide film with a flat and uniform morphology.

Description

Technical Field

[0001] This application relates to the field of two-dimensional atomic-level thin film technology, and in particular to a method for preparing atomic-level multi-metal oxide thin films by laser ablation of liquid metal and the atomic-level multi-metal oxide thin films. Background Technology

[0002] Liquid metal exposed to air forms a natural oxide scale. The oxide scale has a weak interaction with the internal liquid metal, and the oxide scale can be separated from the liquid metal using van der Waals stripping technology. Liquid metal has an electron-rich core, good fluidity, high surface tension, and the ability to dissolve most metals, enabling the transfer of atomically high-quality two-dimensional oxide films.

[0003] However, elemental liquid metals can only be used to prepare single-component metal oxide films; for example, liquid Ga can only form Ga₂O₃ films. Liquid alloys are thermodynamically limited, and their surface oxides can only form single-component metal oxides with low Gibbs free energy (ΔGf), such as GaInSn liquid alloys, which can only produce Ga₂O₃ films. Therefore, this significantly limits the application of liquid metals in the synthesis of two-dimensional multi-component metal oxides. Summary of the Invention

[0004] To address the current challenge of synthesizing two-dimensional multi-metal oxides from liquid metals, this application provides a method for preparing atomic-level multi-metal oxide thin films using laser ablation of liquid metals, and the resulting atomic-level multi-metal oxide thin films.

[0005] In a first aspect, this application provides a method for preparing atomic-level multi-component metal oxide thin films by laser ablation of liquid metal, employing the following technical solution:

[0006] A method for preparing atomic-scale multi-component metal oxide thin films by laser ablation of liquid metal includes the following steps:

[0007] Step S1: Apply liquid metal onto a carrier, place it in a container, and seal it with a metal precursor salt solution;

[0008] Step S2: Perform laser ablation on the liquid metal in the liquid seal to form a thin film of metal oxide on the surface of the liquid metal;

[0009] Step S3: Use van der Waals transfer technology to transfer the metal oxide film from the liquid metal surface to the substrate.

[0010] Optionally, the liquid metal includes elemental metals or alloys containing gallium, bismuth, tin, germanium, indium, titanium, antimony, aluminum, cadmium, cerium, platinum, gold, palladium, iridium, ruthenium, rhodium, cesium, copper, chromium, iron, cobalt, nickel, zinc, manganese, vanadium, tantalum, tungsten, rhenium, osmium, hafnium, rubidium, or strontium.

[0011] When the liquid metal is a liquid alloy, the atomic percentage of a single metal element in the liquid metal will affect the tin content in the synthesized two-dimensional material.

[0012] Optionally, the metal element in the metal precursor salt solution is one or more of gallium, bismuth, tin, germanium, indium, titanium, antimony, aluminum, cadmium, cerium, platinum, gold, palladium, iridium, ruthenium, rhodium, cesium, copper, chromium, iron, cobalt, nickel, zinc, manganese, vanadium, tantalum, tungsten, rhenium, osmium, hafnium, rubidium, or strontium.

[0013] Optionally, the metal precursor salt solution is selected from one of chloride, sulfate, phosphate, and nitrate.

[0014] Optionally, the solvent in the metal precursor salt solution is selected from one or more of ethanol, n-hexane, methanol, water, acetone, and isopropanol.

[0015] The content of metal elements in the metal precursor salt solution affects the degree of diffusion of the metal in the liquid metal, and thus affects the content of the metal element in the two-dimensional thin film material.

[0016] Because pulsed lasers have periods of energy output and energy cessation in a single cycle, during energy output, the local temperature of the liquid metal rises rapidly, accelerating the diffusion of metal elements in the solution into the oxide layer and core of the liquid metal, while simultaneously forming metastable multi-metal oxides on the surface; during energy cessation, the liquid-sealed solution has a rapid cooling effect on the liquid metal, stabilizing the structure of the multi-metal oxides in a metastable state.

[0017] Optionally, the power density of the laser ablation process is 10. 5 ~10 9 W / cm 2 The frequency ranges from 1 Hz to 80 kHz.

[0018] Optionally, the laser used in the laser ablation process is a nanosecond laser, a picosecond laser, or a femtosecond laser.

[0019] Optionally, the laser ablation treatment time is 20-60 minutes.

[0020] Optionally, the laser ablation process takes 30 minutes.

[0021] This application can further control the proportion of metal elements in the oxide film by controlling the laser ablation treatment time. If the laser ablation treatment time is short, the amount of copper diffusion is small, and the proportion of copper element in the formed two-dimensional oxide film is small. As the laser ablation treatment time increases, the proportion of copper element in the two-dimensional oxide film will eventually stabilize and no longer change.

[0022] Optionally, the laser wavelength used in the laser ablation process covers ultraviolet, visible, and near-infrared light.

[0023] Optionally, the carrier is selected from any one of quartz sheet, glass sheet, sapphire, SiO2 / Si sheet, and TEM grid.

[0024] Optionally, the substrate is selected from any one of quartz sheet, glass sheet, sapphire, SiO2 / Si sheet, and TEM grid.

[0025] Optionally, in step S1, when liquid sealing the liquid metal, the same solvent as that in the metal precursor salt solution is used for liquid sealing beforehand, and then the metal precursor salt solution is added.

[0026] Optionally, the van der Waals transfer technique in step S3 can be either a direct-touch peeling method or a spin coating method.

[0027] This application employs van der Waals transfer technology to transfer a multi-metal oxide film formed on the surface of liquid metal. Upon contact, the van der Waals force between the substrate and the surface oxide of the liquid metal is greater than the van der Waals force between the surface oxide of the liquid metal and the liquid metal. The surface oxide of the liquid metal can be easily and completely transferred to the substrate. Therefore, the preparation method of this application can achieve large-scale production.

[0028] Secondly, this application provides an atomic-level multi-metal oxide thin film, which is prepared by the method described above for preparing atomic-level multi-metal oxide thin films by laser ablation of liquid metal.

[0029] In summary, this application includes at least one of the following beneficial effects:

[0030] 1. This invention eliminates the need to consider the lattice matching between the substrate and the material, greatly simplifying the preparation steps of two-dimensional multi-element metal oxide thin films and realizing the synthesis of atomic-level multi-element metal oxide thin films with smooth and uniform morphology.

[0031] 2. This application utilizes laser ablation technology to prepare large-area two-dimensional multi-element metal oxides at room temperature and pressure. The operation is simple and inexpensive, and the reaction conditions are mild and pollution-free.

[0032] 3. This application can control the proportion of metal elements by controlling the amount of liquid metal and the amount of metal precursor salt solution. For example, if the precursor solution contains copper ions, when the liquid gallium is ablated by laser, copper will diffuse from the surface of the liquid metal to the interior, ultimately affecting the ratio of copper and gallium in the oxide film. Attached Figure Description

[0033] Figure 1This is a flowchart of a method for preparing atomic-level multi-component metal oxide thin films by laser ablation of liquid metal according to the present application;

[0034] Figure 2 These are SEM images of the two-dimensional (Cu,Ga)Ox thin film prepared in Example 1 of this application and the elements therein; wherein (a) is an SEM image of the two-dimensional (Cu,Ga)Ox thin film (scale bar: 30 µm), (b) is a distribution map of Ga element on the two-dimensional (Cu,Ga)Ox thin film in (a) (scale bar: 30 µm), (c) is a distribution map of O element on the two-dimensional (Cu,Ga)Ox thin film in (a) (scale bar: 30 µm), and (d) is a distribution map of Cu element on the two-dimensional (Cu,Ga)Ox thin film in (a) (scale bar: 30 µm). Detailed Implementation

[0035] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments, but this should not be construed as limiting the scope of protection of the present application.

[0036] Example 1

[0037] Example 1 provides a method for preparing and synthesizing two-dimensional (Cu,Ga)Ox thin films, see [link to example]. Figure 1 The specific steps are as follows:

[0038] (1) Clean the 2×2 cm glass slide and the 1×1 cm SiO2 / Si sheet with acetone, anhydrous ethanol and deionized water in sequence for 15 min.

[0039] (2) Take 50 µL of metallic Ga, heat it to 60°C and spread it on a glass slide. Place it in a beaker and seal it with 30 ml of anhydrous ethanol.

[0040] (3) Add 20 µL of 0.02 mol / L CuCl2 ethanol solution to the anhydrous ethanol in step (2), and ablate the liquid metal Ga using a nanosecond pulse laser with a pulse width of 5 ns. The average laser power density is set to 2 × 10⁻⁶. 5 W / cm 2 The frequency is 20 kHz, the processing time is 30 min, and the laser wavelength belongs to the infrared band.

[0041] (4) Take out the glass plate coated with liquid gallium, heat it to 60°C, and after the anhydrous ethanol evaporates, touch the liquid metal with the SiO2 / Si plate from step (1) to transfer the oxide film on the surface of the liquid metal to the SiO2 / Si plate. Use a cotton swab to clean away most of the residual liquid metal on the oxide film in anhydrous ethanol at 80°C, and then use a hot iodine ethanol solution to further remove the tiny liquid metal particles on the surface. Ensure that the oxide film structure is not damaged while removing the residual liquid metal, and ensure that the oxide film is clean and flat to obtain a two-dimensional (Cu,Ga)Ox film.

[0042] Figure 2 This is a SEM image of the two-dimensional (Cu,Ga)Ox thin film prepared in Example 1 of this application and its elements. See also... Figure 2 It can be seen that Cu, Ga, and O elements are uniformly distributed in the oxide film prepared in Example 1, indicating that the preparation method of Example 1 can prepare multi-metal oxide films containing Cu and Ga.

[0043] Example 2

[0044] Example 2 provides a method for preparing and synthesizing two-dimensional (Cu,Ga,In,Sn)Ox thin films, the specific steps of which are as follows:

[0045] (1) Clean the 2×2 cm glass slide and the 1×1 cm SiO2 / Si sheet with acetone, anhydrous ethanol and deionized water in sequence for 15 min.

[0046] (2) Take 50 µL of liquid gallium indium tin alloy, apply it to a glass slide, place it in a beaker, and seal it with 30 ml of anhydrous ethanol.

[0047] (3) Add 20 µL of 0.02 mol / L CuCl2 ethanol solution to the anhydrous ethanol in step (2), and ablate the liquid gallium indium tin alloy using a nanosecond pulse laser with a pulse width of 5 ns. The average laser power density is set to 2 × 10⁻⁶. 5 W / cm 2 The frequency is 20 kHz, the processing time is 30 min, and the laser wavelength belongs to the infrared band.

[0048] (4) Take out the glass plate coated with liquid gallium indium tin alloy, heat it to 60°C, and after the anhydrous ethanol evaporates, touch the liquid alloy with the SiO2 / Si sheet in step (1). Use a cotton swab to clean most of the residual liquid metal on the oxide film in anhydrous ethanol at 80°C. Then use hot iodine ethanol solution to further remove the tiny liquid metal particles on the surface. Ensure that the structure of the oxide film is not damaged while removing the residual liquid metal, and ensure that the oxide film is clean and flat to obtain a two-dimensional (Cu,Ga,In,Sn)Ox film.

[0049] Example 3

[0050] Example 3 provides a method for preparing and synthesizing two-dimensional (Cu, Sn, Ni, Pt, Ga)Ox thin films, the specific steps of which are as follows:

[0051] (1) Clean the 2×2 cm glass slide and the 1×1 cm SiO2 / Si sheet with acetone, anhydrous ethanol and deionized water in sequence for 15 min.

[0052] (2) Take 50 µL of metallic gallium, heat it to 60 °C and spread it on a glass slide, place it in a beaker and seal it with 30 ml of anhydrous ethanol.

[0053] (3) Add 20 µL of 0.02 mol / L solutions of copper chloride, tin chloride, nickel chloride, and chloroplatinic acid to the anhydrous ethanol in step (2), respectively, and ablate the liquid gallium metal using a nanosecond pulse laser with a pulse width of 5 ns. The average laser power density is set to 2 × 10⁻⁶. 5 W / cm 2 The frequency is 20 kHz, the processing time is 30 min, and the laser wavelength belongs to the infrared band.

[0054] (4) Take out the glass plate coated with liquid gallium, heat it to 60°C, and after the anhydrous ethanol evaporates, touch the liquid metal with the SiO2 / Si sheet in step (1). Use a cotton swab to clean most of the residual liquid metal on the oxide film in anhydrous ethanol at 80°C. Then use a hot iodine ethanol solution to further remove the tiny liquid metal particles on the surface. Ensure that the structure of the oxide film is not damaged while removing the residual liquid metal, and ensure that the oxide film is clean and flat to obtain a two-dimensional (Cu,Sn,Ni,Pt,Ga)Ox film.

[0055] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A method for preparing atomic-level multi-component metal oxide thin films by laser ablation of liquid metal, characterized in that, Includes the following steps: Step S1: Apply liquid metal onto a carrier, place it in a container, and seal it with a metal precursor salt solution; Step S2: Perform laser ablation on the liquid metal in the liquid seal to form a thin film of metal oxide on the surface of the liquid metal; Step S3: Use van der Waals transfer technology to transfer the metal oxide film from the liquid metal surface to the substrate.

2. The method for preparing atomic-level multi-component metal oxide thin films by laser ablation of liquid metal according to claim 1, characterized in that, The liquid metal includes elemental metals or alloys containing gallium, bismuth, tin, germanium, indium, titanium, antimony, aluminum, cadmium, cerium, platinum, gold, palladium, iridium, ruthenium, rhodium, cesium, copper, chromium, iron, cobalt, nickel, zinc, manganese, vanadium, tantalum, tungsten, rhenium, osmium, hafnium, rubidium, or strontium.

3. The method for preparing atomic-level multi-component metal oxide thin films by laser ablation of liquid metal according to claim 1, characterized in that, The metal element in the metal precursor salt solution is one or more of gallium, bismuth, tin, germanium, indium, titanium, antimony, aluminum, cadmium, cerium, platinum, gold, palladium, iridium, ruthenium, rhodium, cesium, copper, chromium, iron, cobalt, nickel, zinc, manganese, vanadium, tantalum, tungsten, rhenium, osmium, hafnium, rubidium, or strontium.

4. The method for preparing atomic-level multi-component metal oxide thin films by laser ablation of liquid metal according to claim 1, characterized in that, The metal precursor salt solution is selected from one of chloride, sulfate, phosphate, and nitrate.

5. The method for preparing atomic-level multi-component metal oxide thin films by laser ablation of liquid metal according to claim 1, characterized in that, The solvent in the metal precursor salt solution is selected from one or more of anhydrous ethanol, n-hexane, methanol, water, acetone, and isopropanol.

6. The method for preparing atomic-level multi-component metal oxide thin films by laser ablation of liquid metal according to claim 1, characterized in that, The power density of the laser ablation process is 10. 5 ~10 9 W / cm 2 The frequency ranges from 1 Hz to 80 kHz.

7. The method for preparing atomic-level multi-component metal oxide thin films by laser ablation of liquid metal according to claim 1, characterized in that, The substrate is selected from any one of quartz sheet, glass sheet, sapphire, SiO2 / Si sheet, and TEM grid.

8. The method for preparing atomic-level multi-component metal oxide thin films by laser ablation of liquid metal according to claim 1, characterized in that, In step S1, when the liquid metal is liquid-sealed, the same solvent as that in the metal precursor salt solution is used for liquid sealing before the metal precursor salt solution is added.

9. The method for preparing atomic-level multi-component metal oxide thin films by laser ablation of liquid metal according to claim 1, characterized in that, The van der Waals transfer technique in step S3 is either direct contact peeling or spin coating.

10. An atomically-scale multi-element metal oxide thin film, characterized in that, It is prepared by the method of preparing atomic-level multi-element metal oxide thin films by laser ablation of liquid metal according to any one of claims 1-9.

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