CN103011185B - Preparation method for mica flakes having nanostructure - Google Patents

Abstract

The present invention relates to a method for preparing mica flakes having a nanostructure by using atomic force microscope micromechanical processing. According to the present invention, a mechanical stripping method is adopted to prepare monolayer or a few layers of mica flakes, and the mica flakes can be adopted as a substrate to prepare a nanostructure on the obtained mica flake by using an atomic force microscope micromechanical processing method, wherein the nanostructure can be obtained through the following steps: placing the mica flake on a solid substrate so as to make the work of the atomic force microscope in a contact mode, and controlling acting force of contact of the atomic force microscope tip and the mica flake so as to control the obtained nanostructure on the mica flake; the method for preparing the mica flakes by using the micromechanical stripping method has characteristics of simple operation method, convenient and easy performing, and less defects; and the nanostructure prepared by using the atomic force microscope micromechanical processing method has characteristics of controllable thickness, atomic level accuracy, controllable shape and controllable position, wherein the patterned nanostructure can be prepared.

Description

Preparation method of mica flakes with nanostructure

technical field

The invention relates to a method for preparing mica flakes with nanostructures by means of atomic force microscope micromachining.

Background technique

In recent years, single-layer or few-layer layered crystal two-dimensional materials represented by graphene have attracted widespread attention due to their excellent properties and broad application prospects. As a layered material with perfect cleavability, mica is an excellent source of 2D materials. Because mica has chemical inertness, thermal insulation and electrical insulation, which are completely different from graphene, it has unique and important application value in some fields. The nanostructure preparation technology of two-dimensional materials based on a single layer or a few layers is currently concentrated on conductive graphene. The research on graphene shows the uniqueness of two-dimensional materials in the field of nanostructures, especially ultra-thin asymmetric nanopores. Advantages (Garaj, S.; Hubbard, W.; Reina, A.; Kong, J.; Branton, D.; Golovchenko, J.A. Nature 2010, 467, 190). However, there are still few reports on the preparation of nanostructures of layered crystal two-dimensional materials based on insulating monolayers or few layers, and the methods for preparing nanostructures of other two-dimensional materials are mainly electron beam or ion beam etching (Dekker, C.Nature Nanotechnology 2007, 2, 209), the process of the above method is complex and expensive. Finding a simple, effective and low-cost method to prepare nanostructures of two-dimensional materials, especially nanostructures of two-dimensional materials based on insulating monolayer or layered crystals with a few layers, is still a major difficulty.

The method of atomic force microscope micromachining has the advantages of simple and effective preparation process and low cost. It can precisely control the thickness, position and shape of the nanostructure of two-dimensional materials, and prepare patterned nanostructures. In addition to mica, this method is also applicable to other two-dimensional materials. dimensional material.

Contents of the invention

The purpose of the present invention is to provide a method for preparing mica flakes with nanostructures by means of atomic force microscope micromachining.

The method of the present invention involves the preparation of single-layer or few-layer mica flakes by mechanical exfoliation, and the mica flakes can be used as a base to prepare nanostructures on the obtained mica flakes by means of atomic force microscope micromachining.

The method for preparing mica flakes with nanostructures by using atomic force microscope micromachining of the present invention: place the mica flakes on a solid substrate, make the work of the atomic force microscope in contact mode, and control the contact between the needle tip of the atomic force microscope and the mica flakes force to control the resulting nanostructures on mica flakes.

The shape and position of the nanostructure are controlled by scanning the position of the mica flakes with the tip of the atomic force microscope and the size of the area of the mica flakes.

The nanostructures obtained on the mica flakes are selected from at least one of nanoholes, nanowires, polygons with sides greater than or equal to three, circles, and the like.

The mica flakes are selected from one of artificially synthesized mica flakes, naturally grown phlogopite mica flakes, naturally grown muscovite mica flakes, and naturally grown biotite flakes.

The number of layers of the mica flakes is 1-100 layers.

The layer in the number of layers of mica flakes refers to a layer of mica molecular structure unit.

The mica flakes described in the present invention can be obtained by the following method: stick the two sides of a piece of mica on the adhesive tape respectively, tear off the tape, peel off a piece of mica into two mica sheets, and then stick the two sides of the mica sheets obtained by peeling On the adhesive tape, the adhesive tape is torn off, and the mica sheet is peeled off into two mica sheets; the above steps are repeated to obtain a mica sheet with the required number of layers, preferably a mica sheet with 1 to 100 layers. The selection of the mica flakes with the required number of layers is to transfer the mica flakes on the adhesive tape to a solid substrate, use an optical microscope combined with an atomic force microscope to characterize the thickness and the number of layers of the mica flakes, and select the mica flakes with the required number of layers.

The method for characterizing the thickness and the number of layers of the mica flakes by using an optical microscope in combination with an atomic force microscope is to record the characteristic color of the mica flakes or the light intensity of the mica flakes and the surrounding solid substrates with an optical microscope after the mica flakes are transferred to a solid substrate Contrast, and then use the atomic force microscope to record the thickness of the mica flakes, and obtain the corresponding relationship between the optical characteristics and thickness of the mica flakes, so that it is convenient to find the mica flakes with the required number of layers according to the optical characteristics in the future.

The mica is selected from one of artificially synthesized mica, naturally grown phlogopite, naturally grown muscovite, and naturally grown biotite.

Said tapes include various cloth or plastic films coated with sticky rubber.

The layer in the number of layers of mica flakes refers to a layer of mica molecular structure unit.

The material of the solid substrate is selected from one or more of silicon, magnesium, aluminum, iron, copper, nickel, zinc, gold, silver or their oxides or nitrides, or selected from carbon, or selected from Any two or more of the above materials.

The operation method of preparing mica flakes by using the mechanical peeling method involved in the method of the present invention is simple, convenient and easy to implement, and has few defects. The thickness of the nanostructure prepared by the atomic force microscope micromachining method involved in the method of the present invention is controllable, the precision reaches the atomic level, the shape and position of the nanostructure are controllable, and a patterned nanostructure can be prepared. In addition to mica, The invention is also applicable to other two-dimensional materials.

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

Description of drawings

Figure 1. Schematic illustration of the preparation of single-layer or few-layer mica flakes for mechanical exfoliation, and the preparation of nanostructures by AFM micromachining.

Fig. 2. the mechanical exfoliation method of the embodiment of the present invention 1, 2, 3, 4 prepares the photo of optical microscope and atomic force microscope of 8 layers, 28 layers, 9 layers, 6 layers of mica flakes, as shown in the second row ( Figure 2a-c), the first row (Figure 2d-f), the third row (Figure 2g-i), the fourth row (Figure 2j-1), where the solid substrate in the second row is 250nm Silicon oxide/silicon (i.e. 250nm thick silicon dioxide covered on a silicon substrate), the solid substrate in the first row is a silicon substrate, and the solid substrate in the third row is a 300nm silicon dioxide/silicon (i.e. 300 nanometer-thick silicon dioxide over a silicon substrate), the solid substrate in the fourth row is 500nm silica/silicon (i.e., 500nm thick silicon dioxide over a silicon substrate), and the solid substrate in each row above The first column is an optical photo, the second column is an atomic force microscope photo, and the third column is an atomic force height map.

Fig. 3. the optical and atomic force microscope photos of the ultrathin asymmetric nanohole prepared on the 10-layer mica sheet on the solid substrate of 250nm silicon dioxide/silicon by atomic force micromachining method of the embodiment of the present invention; a The picture is its atomic force microscope photo; picture b is its optical picture, the inset in the upper right corner of picture b is the optical picture of the solid substrate, the small end of the prepared ultra-thin asymmetric nanopore is about 68 nanometers, and the hole depth is 9.6 nanometers; picture c is a schematic diagram of the shape of an ultrathin asymmetric nanopore, and the nanopore is a square.

Fig. 4. When controlling the application of different forces in which the tip of the atomic force microscope contacts the mica flakes in Examples 1 and 6 of the present invention, the three-dimensional atomic force micrographs of the ultra-thin asymmetric nanopores of different depths obtained, when the forces are respectively 863 nanonew (nN), 1613 nanonew (nN), 2363 nanonew (nN), 3112 nanonew (nN), 3863 nanonew (nN), a series of nanopores with a depth of 2, 4 , 7, 8, and 9 layers of mica molecular structure units, as shown in Figure 4a-e, and Figure 4f is the statistical diagram of Figure 4a-e.

Fig. 5. The tip scanning area of the control atomic force microscope in Example 1 of the present invention is 120 nanometers × 120 nanometers, and the ultra-thin asymmetric nanopore with a large mouth end of about 120 nanometers × 120 nanometers and a small mouth end of about 20 nanometers × 20 nanometers is obtained , Figure a is a top view of an atomic force microscope, and Figure b is an inverted three-dimensional image of an atomic force microscope.

Fig. 6. The tip scanning areas of the control atomic force microscopes of Examples 1 and 5 of the present invention are 15 nanometers × 15 nanometers, 30 nanometers × 30 nanometers, 60 nanometers × 60 nanometers, 80 nanometers × 80 nanometers, 100 nanometers × 100 nanometers, 120nm×120nm, 180nm×180nm, 250nm×250nm, 300nm×300nm, 500nm×500nm, a series of ultra-thin asymmetric nanopores with different shapes and sizes are obtained, as shown in Figure 6a, b, c, d, e, f, g, h, i, j, k.

Figure 7. A schematic diagram of patterned nanostructures of different shapes obtained by controlling the tip scanning area and scanning position of the atomic force microscope for multiple scans of Examples 12-16 of the present invention, wherein the a-e diagrams are array square, array triangle, array Schematic diagram of nanostructures of circles, nanowires, and crossed nanowires.

Detailed ways

Example 1.

1), preparation of mica flakes

Stick the two sides of a piece of naturally growing muscovite on the adhesive plaster respectively, tear off the adhesive plaster, peel off one piece of muscovite into two muscovite sheets, and then stick the two sides of the obtained muscovite sheet on the adhesive plaster respectively, Tear off the adhesive tape, and then peel off the muscovite flakes obtained in the previous peeling into two muscovite flakes; repeat the above steps several times to obtain mica flakes with the required number of layers;

2), transfer and find the mica flakes with the required number of layers

Stick the adhesive plaster obtained in step 1) on the solid substrate of 250nm silica/silicon, tear off the adhesive plaster, and the mica flakes on the adhesive plaster are transferred to the solid substrate of 250nm silica/silicon, and place the solid substrate on Observed under an optical microscope, micron-scale flaky mica flakes can be observed, and the color of the mica flakes changes with its thickness. Record the characteristic color of the observed mica flakes or their relationship with the surrounding solid substrate (that is, there is no mica above the 250nm two Silicon oxide/silicon) light intensity contrast, and then use the atomic force microscope to measure the thickness of this mica flake and record it, so as to establish the corresponding relationship between the optical characteristics and thickness of the mica flake, and find the mica flake with the required number of layers according to the optical characteristics, please See the second line in Figure 2, the characteristic color and light intensity contrast of the mica flakes in the e picture and the thickness (8 layers) of the mica flakes in the f picture and the g picture establish a one-to-one correspondence, and then use an optical microscope to observe When encountering mica flakes of the same color or optical contrast, their thickness can be determined without the observation of the atomic force microscope, and then the corresponding relationship between the optical characteristics and the thickness can be determined by using the same above-mentioned optical microscope and atomic force microscope observation, and then A 10-layer mica flake as shown in Figure 3 can be found by using an optical microscope to search alone;

3) Preparation of mica flakes with nanostructures using atomic force microscope micromachining

Using the atomic force microscope in contact mode, the tip of the atomic force microscope uses a tip coated with harder materials such as silicon nitride or diamond, and the mica flakes obtained in step 2) are placed on a solid substrate of 250nm silicon dioxide/silicon, so that The work of the atomic force microscope is in the contact mode, and the force of the contact between the tip of the atomic force microscope and the mica sheet is controlled, and the force is gradually increased. The 10-layer mica sheet obtained in step 2) is scanned by the tip of the atomic force microscope to prepare ultra-thin Asymmetric nanopores. The force between the tip of the atomic force microscope and the mica sheet is controlled to control the thickness of the ultra-thin asymmetric nanopore. When the control force is 3863 nanonewtons, the prepared ultra-thin square asymmetric nanopore has a depth of about 9.6 nanometers ( 9-layer mica molecular structure unit), the small mouth end is about 68 nanometers, the atomic force micrograph shown in Figure 3a and the optical micrograph shown in Figure 3b, and the three-dimensional shape of the ultrathin asymmetric nanopore is shown in Figure 3c The schematic diagram of the shape and the depth of the ultrathin asymmetric nanopore are shown in Fig. 4e.

Control the scanning position and area of the tip of the atomic force microscope to control the size of the ultra-thin asymmetric nanopores prepared on the mica sheet. For example, the scanning area is controlled to be 120 nm × 120 nm, and the large end is about 120 nm × 120 nm, and the small end is about 120 nm × 120 nm. Ultrathin square asymmetric nanopores of approximately 20 nm × 20 nm, as shown in the atomic force micrograph in Figure 5a, the inverted three-dimensional image of the atomic force microscope in Figure 5b, and the atomic force micrograph in Figure 6f picture.

Example 2. Preparation of ultrathin asymmetric nanopores based on mica flakes

The preparation method is basically the same as in Example 1, except that a silicon wafer is used as a solid substrate, and the mica flakes obtained on it are shown in the optical photo of Figure 2a, the atomic force micrograph of Figure 2b and the height map of Figure 2c.

Example 3. Preparation of ultrathin asymmetric nanopores based on mica flakes

The preparation method is basically the same as that in Example 1, the difference is: a solid substrate of 300nm silica/silicon is used, and the mica flakes obtained on it are as shown in the optical photo of Figure 2h, the atomic force micrograph of Figure 2i and the height of Figure 2j As shown in the figure.

Example 4. Preparation of ultrathin asymmetric nanopores based on mica flakes

The preparation method is basically the same as in Example 1, the difference is: a solid substrate of 500nm silicon dioxide/silicon is used, and the mica flakes obtained on it are as shown in the optical photo of Figure 2k, the atomic force micrograph of Figure 21 and the height of Figure 2m As shown in the figure.

Example 5. Preparation of ultrathin asymmetric nanopores based on mica flakes

The preparation method is basically the same as that in Example 1, except that the control scanning area is 15 nanometers × 15 nanometers, 30 nanometers × 30 nanometers, 60 nanometers × 60 nanometers, 80 nanometers × 80 nanometers, 100 nanometers × 100 nanometers, and 180 nanometers × 180 nm, 250 nm × 250 nm, 300 nm × 300 nm, 500 nm × 500 nm, to obtain a series of ultra-thin asymmetric nanopores of different shapes and sizes, as shown in Figure 6 a, b, c, d , e, g, h, i, j, k, it can be seen that the shape and size of the nanopore can be accurately controlled by the scanning area.

Example 6. Preparation of ultrathin asymmetric nanopores based on mica flakes

The preparation method is basically the same as in Example 1, the difference is: gradually increase the force of the tip of the atomic force microscope on the mica flakes, the force is from 863 nanonew to 1613 nanonew, 2363 nanonew, 3112 nanonew, and the mica is peeled off layer by layer The ultrathin asymmetric nanopores were fabricated to obtain a series of nanopores with depths of 2, 4, 7, and 8 layers of mica molecular structural units, as shown in Fig. 4a-d, respectively.

Example 7. Preparation of ultrathin asymmetric nanopores based on mica flakes

The preparation method is basically the same as in Example 1, except that the number of mica flakes used is 100 layers.

Example 8. Preparation of ultrathin asymmetric nanopores based on single-layer mica flakes

The preparation method is basically the same as in Example 1, except that the mica flake used is a single layer.

Example 9. Preparation of ultrathin asymmetric nanopores based on mica flakes

The preparation method is basically the same as in Example 1, except that the mica used is selected from artificially synthesized mica.

Example 10. Preparation of ultrathin asymmetric nanopores based on mica flakes

The preparation method is basically the same as in Example 7, except that the mica used is selected from artificially synthesized mica.

Example 11. Preparation of ultrathin asymmetric nanopores based on single-layer mica flakes

The preparation method is basically the same as in Example 8, except that the mica used is selected from artificially synthesized mica.

Example 12. Preparation of mica flake-based nanostructures and patterned nanostructures

The preparation method is basically the same as in Example 1, except that in step 3), the tip of the atomic force microscope is controlled to scan at different pre-selected positions to obtain arrays of triangles, squares, circles, nanowires, and cross-shaped nanowires. nanostructures, as shown in Fig. 7a-e.

Example 13. Preparation of mica flake-based nanostructures and patterned nanostructures

The preparation method is basically the same as in Example 12, except that 100 layers of mica flakes are used.

Example 14. Preparation of nanostructures and patterned nanostructures based on single-layer mica flakes

The preparation method is basically the same as in Example 13, except that the mica flake used is a single layer.

Example 15. Preparation of nanostructures and patterned nanostructures based on single-layer mica flakes

The preparation method is basically the same as in Example 14, except that the mica used is selected from artificially synthesized mica.

Example 16. Preparation of nanostructures and patterned nanostructures based on single-layer mica flakes

The preparation method is basically the same as in Example 15, except that in step 3), the tip of the atomic force microscope is controlled to scan at different pre-selected positions to obtain arrays of triangles, squares, circles, nanowires, and cross-shaped nanowires. nanostructures, as shown in Fig. 7a-e.

Claims (5)

1. a kind of preparation method of mica sheet is characterized in that: the two sides of a piece of mica are stuck on the adhesive tape respectively, tear off adhesive tape, a piece of mica is peeled off into two pieces of mica sheets, then the two sides of the mica sheet that peels off are glued respectively On the tape, tear off the tape, then peel off the mica sheet into two mica sheets; repeat the above steps to obtain the required number of mica sheets; the selection of the required layers of mica sheets is to transfer the mica sheets on the tape to On the solid substrate, use an optical microscope combined with an atomic force microscope to characterize the thickness and number of layers of the mica flakes, and select the mica flakes with the required number of layers. 2. method according to claim 1, it is characterized in that: the described method utilizing optical microscope in conjunction with atomic force microscope to characterize the thickness of mica flake and the number of layers is after mica flake is transferred on the solid substrate, records with optical microscope The characteristic color of the mica flakes or the light intensity contrast between the mica flakes and the surrounding solid substrate, and then use the atomic force microscope to record the thickness of the mica flakes, and obtain the corresponding relationship between the optical characteristics and the thickness of the mica flakes, and find the required number of layers according to the optical characteristics. Mica flakes. 3. The method according to claim 1, characterized in that: the mica is selected from the group consisting of artificially synthesized mica, naturally grown phlogopite, naturally grown muscovite, and naturally grown biotite. 4. The method of claim 1, wherein said adhesive tape comprises cloth or plastic film coated with adhesive rubber. 5. The method according to claim 1, characterized in that: the material of the solid substrate is selected from silicon, magnesium, aluminum, iron, copper, nickel, zinc, gold, silver or their oxides or nitrides One or more of them, or selected from carbon, or selected from any two or more of the above materials.