TWI411005B - Method for making transmission electron microscope grid - Google Patents

Abstract

The invention relates to a method for making a transmission electron microscope grid. The method includes the following steps of: supplying a lamellar carbon nanotube structure; irradiating the lamellar carbon nanotube structure by laser to form a plurality of holes, thereby forming a plurality of electron transmission portions; and cutting the lamellar carbon nanotube structure with a plurality of electron transmission portions to form the transmission electron microscope grid.

Description

Equipment for TEM micro-grid

The invention relates to a preparation method of a transmission electron microscope micro-gate, in particular to a preparation method of a transmission electron microscope micro-gate based on a carbon nanotube.

In transmission electron microscopy, porous carbon support membranes (microgrids) are important tools for carrying powder samples for high-resolution image observation (HRTEM) observation by transmission electron microscopy. With the continuous development of nanomaterial research, microgrids are increasingly used in the field of electron microscopy characterization of nanomaterials. In the prior art, the microgrid applied to a transmission electron microscope is usually formed by covering a metal mesh such as a copper mesh or a nickel mesh with a porous organic film and then vapor-depositing an amorphous carbon film. However, when the above-mentioned micro-gate is used to analyze the composition of the TEM high-resolution image of the sample to be tested, the metal mesh often contains a large amount of impurities, such as metal oxides, and the interference of the component analysis of the sample to be tested is large.

Since the early 1990s, nanomaterials represented by carbon nanotubes (see Helical microtubules of graphitic carbon, Nature, Sumio Iijima, vol 354, p56 (1991)) have caused people with their unique structure and properties. Great attention. The application of carbon nanotubes to the fabrication of microgrids is beneficial to reduce the interference of metal grids on the analysis of the components of the sample being tested.

In view of this, it is necessary to provide a preparation method of a TEM micro-gate based on a carbon nanotube, and the prepared TEM micro-grid has less interference to the analysis of the component of the sample to be tested.

A method for preparing a transmission electron microstrip, the method comprising the steps of: providing a piece of nanocarbon a tube structure; laser-perforating the sheet-shaped carbon nanotube structure to form a plurality of electron-transmissive portions; and cutting the sheet-shaped carbon nanotube structure having an electron-transmissive portion to form the transmission Electron micromirror.

Compared with the prior art, the TEM microgrid provided by the present invention is prepared by laser perforating a sheet-shaped carbon nanotube structure and cutting the sheet-shaped carbon nanotube structure by a predetermined size without an evaporation process. Therefore, the preparation method is relatively simple. The prepared TEM micro-gate is composed of a disk-shaped carbon nanotube structure, no metal mesh is needed, and the carbon nanotube structure is relatively pure, which can effectively eliminate the metal mesh in the conventional micro-grid when analyzing the components of the sample to be tested. The interference is beneficial to improve the accuracy of component analysis using TEM.

10‧‧‧Transmission electron microscopy

102‧‧‧Ontology

104‧‧‧Electronic Transmission Department

106‧‧‧Nano Carbon Tube

108‧‧‧Micropores

1 is a schematic perspective view showing the structure of a transmission electron microscope micro-gate according to an embodiment of the present invention.

2 is a cross-sectional structural view of a TEM micro-gate according to an embodiment of the present invention.

3 is a scanning electron micrograph of a carbon nanotube flocculation film in a TEM microgrid according to an embodiment of the present invention.

4 is a scanning electron micrograph of a carbon nanotube rolled film in a TEM microgrid according to an embodiment of the present invention.

FIG. 5 is a scanning electron micrograph of a carbon nanotube film in a transmission electron microscope micro-gate according to an embodiment of the present invention.

FIG. 6 is a schematic flow chart of a method for preparing a TEM micro-gate according to an embodiment of the present invention.

The TEM micro-gate of the present invention and its preparation method will be further described in detail below with reference to the accompanying drawings.

Referring to FIG. 1 and FIG. 2 together, the present invention provides a TEM micro-gate 10. The TEM microgrid 10 is a carbon nanotube structure for carrying a sample to be tested. The carbon nanotube structure may be in the form of a disk having a diameter of about 3 mm. The disk-shaped carbon nanotube structure is composed of a plurality of carbon nanotubes supporting structure. The disk-shaped carbon nanotube has a relatively pure structure and contains substantially no impurities. The wafer-shaped carbon nanotube structure includes a body 102 and a plurality of electron transmissive portions 104 distributed on the surface of the body 102. The density of the electron transmissive portion 104 is smaller than the density of the body 102.

The surface of the body 102 has a plurality of micropores 108 each having a plurality of carbon nanotubes 106 therein. Each of the micro holes 108 corresponds to an electron transmissive portion 104. That is, the electron transmissive portion 104 is composed of a carbon nanotube 106 disposed in the micropore 108. The electron transmissive portion 104 is used to carry a sample to be tested for transmission electron microscope observation. The density of the electron-transmissive portion 104 (the density of the carbon nanotube distribution in the electron-transmissive portion 104) may be 1/900 to 1/10 of the density of the body 102 (the density of the carbon nanotube distribution in the body 102). Preferably, the density of the electron transmissive portion 104 may be 1/500 to 1/10 of the density of the body 102. The electron transmissive portion 104 can be formed by irradiating a body 102 of a disk-shaped carbon nanotube structure with a laser. Due to the action of the laser, the body 102 is ablated by the portion of the carbon nanotube 106 at the laser irradiation position, and the density is lowered to form the micropores 108, thereby forming the electron transmissive portion 104. The shape of the microholes 108 is not limited, and may be circular, square or elliptical, etc., depending on the selection of different shapes of laser beams or different laser illumination methods. The size of the micro-holes 108 is not limited and can be adjusted according to actual application requirements. Preferably, the micropores 108 are circular holes, and the micropores 108 have a diameter of about 10 micrometers to 200 micrometers. The plurality of electron transmissive portions 104 are evenly distributed on the surface of the body 102, and the arrangement of the plurality of electron transmissive portions 104 is not limited. The distance between the adjacent electron transmissive portions 104 may be equal or unequal. Preferably, the plurality of electron transmissive portions 104 are distributed in the body 102 in an array, and the distance between adjacent electron transmissive portions 104 is equal. The distance between the adjacent electron transmissive portions 104 may be greater than 1 micron.

A plurality of carbon nanotubes 106 in the electron transmissive portion 104 are used to support the sample to be tested. The carbon nanotubes 106 in the electron transmissive portion 104 are a part of the entire body 102 and are integral with the body 102. Specifically, the carbon nanotubes 106 may be supported by the body 102 of the inner wall of the micropores 108. Specifically, both ends of the plurality of carbon nanotubes 106 in the micropores 108 can be inserted into the inner wall of the micropores 108. In body 102. The plurality of carbon nanotubes 106 may be disposed in parallel or in a cross arrangement. Preferably, the plurality of carbon nanotubes 106 are spatially arranged in a cross. A plurality of sub-micropores (not shown) are further formed between the plurality of carbon nanotubes 106 disposed at the intersection. The pore size of the micropores is between 1 nm and 1 μm. The carbon nanotubes 106 in the micropores 108 are suspended.

The disk-shaped carbon nanotube structure is a self-supporting structure and has certain supporting properties. Preferably, the disk-shaped carbon nanotube structure has better support properties. The self-supporting disk-shaped carbon nanotube structure does not require a large-area carrier support, and as long as the supporting force is provided on both sides, it can be suspended as a whole to maintain its own sheet-like structure. The wafer-shaped carbon nanotube structure may include at least one layer of carbon nanotube film. The number of layers of the carbon nanotube film constituting the disk-shaped carbon nanotube structure is determined according to the thickness of the single-layer carbon nanotube film, and the wafer-shaped carbon nanotube structure has good support performance. . It can be understood that the smaller the thickness of the single-layer carbon nanotube film, the more the number of layers of the carbon nanotube film in the disk-shaped carbon nanotube structure; the greater the thickness of the single-layer carbon nanotube film, The fewer the number of layers of the carbon nanotube film in the disk-shaped carbon nanotube structure. The adjacent two layers of carbon nanotube membranes can be tightly bonded by van der Waals force.

The carbon nanotube film may be a carbon nanotube film, a carbon nanotube film or a carbon nanotube film.

The carbon nanotube flocculation membrane comprises a plurality of carbon nanotubes which are intertwined and uniformly distributed. The carbon nanotubes are attracted and entangled with each other by a van der Waals force to form a network structure to form a self-supporting carbon nanotube floc membrane. The scanning electron micrograph can be seen in FIG. The carbon nanotube flocculation membrane is isotropic. The carbon nanotube flocculation membrane can be obtained by flocculation treatment on a carbon nanotube array. The carbon nanotube flocculation film and the preparation method thereof are described in the Chinese Patent Application No. 200844041 published on November 16, 2008. To save space, all of the technical disclosures in the application are also considered to be part of the disclosure of the present application. It is to be noted that the carbon nanotube flocculation membrane is not limited to the above preparation method. The carbon nanotube film has a thickness of from 1 micrometer to 2 millimeters. The carbon nanotube structure may include only one layer of carbon nanotube flocculation membrane By adjusting its thickness to ensure its better support performance.

The carbon nanotube rolled film comprises a plurality of carbon nanotubes arranged in disorder, arranged in a preferred orientation in one direction or in a preferred orientation in a plurality of directions, and the adjacent carbon nanotubes are combined by a van der Waals force. The carbon nanotube rolled film can be obtained by extruding the carbon nanotube array in a direction perpendicular to the substrate grown by the array of carbon nanotubes by using a planar indenter, and the carbon nanotube is rolled at this time. The carbon nanotubes in the membrane are disorderly arranged, and the carbon nanotube membrane is isotropic; the carbon nanotube membrane can also be rolled in a fixed direction by a roller-shaped indenter. Obtained by the carbon nanotube array, wherein the carbon nanotubes in the carbon nanotube rolled film are arranged in a preferred orientation in the fixed direction; the carbon nanotube rolled film may also adopt a roller-shaped indenter Obtaining the above-mentioned carbon nanotube arrays in different directions, wherein the carbon nanotubes in the carbon nanotube rolled film are arranged in different directions in a preferred orientation. At this time, the carbon nanotube rolled film can be The plurality of sections are included, and the carbon nanotubes in each section are arranged in a preferred orientation in one direction, and the arrangement directions of the carbon nanotubes in the adjacent two sections may be different. See Figure 4 for a scanning electron micrograph of the carbon nanotube rolled film. The carbon nanotube rolled film and the preparation method thereof are described in the Chinese Patent Application No. 200900348 published on January 1, 2009. To save space, all of the technical disclosures in the application are also considered to be part of the disclosure of the present application. The carbon nanotube rolled film has a thickness of 1 micrometer to 1 millimeter. The carbon nanotube structure may include only one layer of carbon nanotube rolled film, and its thickness is adjusted to achieve better support performance.

Referring to FIG. 5, the carbon nanotube film is a self-supporting structure composed of a plurality of carbon nanotubes. The plurality of carbon nanotubes are arranged in a preferred orientation along the same direction. The preferred orientation means that the overall extension direction of most of the carbon nanotubes in the carbon nanotube film is substantially in the same direction. Moreover, the overall extension direction of the majority of the carbon nanotubes is substantially parallel to the surface of the carbon nanotube film. Further, most of the carbon nanotubes in the carbon nanotube film are connected end to end by Van der Waals force. Specifically, each of the carbon nanotubes in the majority of the carbon nanotubes extending substantially in the same direction in the carbon nanotube film is drawn The carbon nanotubes adjacent to the extending direction are connected end to end by Van Valle. Of course, there are a small number of randomly arranged carbon nanotubes in the carbon nanotube film, and these carbon nanotubes do not significantly affect the overall orientation of most of the carbon nanotubes in the carbon nanotube film. The self-supporting carbon nanotube film does not require a large-area carrier support, and as long as the support force is provided on both sides, it can be suspended in the whole to maintain its own film state, that is, the carbon nanotube film is placed (or When fixed on two supports arranged at a certain distance, the carbon nanotube film located between the two supports can be suspended to maintain its own film state. The self-supporting is mainly achieved by the presence of continuous carbon nanotubes extending through the end-to-end extension of the van der Waals force in the carbon nanotube film.

Specifically, most of the carbon nanotubes extending substantially in the same direction in the carbon nanotube film are not absolutely linear, and may be appropriately bent; or may not be completely aligned in the extending direction, and may be appropriately deviated from the extending direction. Therefore, it is not possible to exclude partial contact between the carbon nanotubes juxtaposed in the majority of the carbon nanotubes extending substantially in the same direction of the carbon nanotube film. Specifically, each carbon nanotube film comprises a plurality of carbon nanotube segments arranged in a continuous and preferential orientation. The plurality of carbon nanotube segments are connected end to end by Van Valle. Each of the carbon nanotube segments includes a plurality of substantially parallel carbon nanotubes, and the plurality of substantially parallel carbon nanotubes are tightly coupled by a van der Waals force. The carbon nanotube segments have any length, thickness, uniformity, and shape. The carbon nanotubes in the carbon nanotube film are arranged in a preferred orientation in the same direction. The carbon nanotube film is obtained by drawing from a carbon nanotube array. The thickness of the carbon nanotube film is from 0.5 nm to 100 μm depending on the height and density of the carbon nanotubes in the carbon nanotube array. The width of the carbon nanotube film is related to the size of the carbon nanotube array for pulling the carbon nanotube film, and the length is not limited. The structure of the carbon nanotube film and the preparation method thereof are described in the Chinese Patent Application No. 200833862, published on Aug. 16, 2008. When the thickness of the carbon nanotube film is from 0.5 nm to 100 μm, the carbon nanotube structure may include 10 or more laminated carbon nanotube films. Preferably, the carbon nanotube structure may include a carbon nanotube film disposed in a layer of more than 100 layers.

When the disk-shaped carbon nanotube structure comprises a plurality of carbon nanotube membranes and the carbon nanotubes in each of the carbon nanotube membranes are arranged in a preferred orientation in the same direction, in the adjacent two layers of carbon nanotube membranes The arrangement of the carbon nanotubes may be the same or different. Specifically, the carbon nanotubes in the adjacent carbon nanotube film have an intersection angle α between the α and the α is greater than or equal to 0 degrees and less than or equal to 90 degrees. When the carbon nanotubes in the plurality of carbon nanotube membranes in the disk-shaped carbon nanotube structure have an intersection angle α and α is not equal to 0 degrees, that is, when a plurality of carbon nanotube membranes are disposed at the intersection The carbon nanotubes are interwoven to form a network structure, which enhances the mechanical properties of the wafer-shaped carbon nanotube structure.

It can be understood that the intersection of a plurality of carbon nanotube membranes does not require any two adjacent layers of carbon nanotube membranes to be intersected, that is, the majority of carbon nanotubes in the adjacent two layers of carbon nanotube membranes are allowed to exist. The arrangement direction is the same, but it is necessary to ensure that the intersection angle between the arrangement directions of the majority of the carbon nanotubes in at least two layers of the carbon nanotube film is greater than 0 degrees and less than or equal to 90 degrees. .

In this embodiment, the disk-shaped carbon nanotube structure comprises a 100-layer carbon nanotube film, and the carbon nanotubes in the adjacent two layers of carbon nanotube film have an intersection angle α, and This α is equal to 90 degrees. The disk-shaped carbon nanotube structure is composed of a body 102 and a plurality of electron transmissive portions 104 distributed on the surface of the body 102. The surface of the body 102 has a plurality of circular micropores 108. Each of the electron transmissive portions 104 is composed of a plurality of carbon nanotubes 106 corresponding to each of the circular micropores 108. The electron transmissive portion 104 has a density of one-fiftieth (1/50) the density of the body 102. The circular micropores 108 have a pore size between 30 microns and 150 microns. A plurality of carbon nanotubes 106 in the micropores 108 are arranged to form a plurality of secondary micropores. The pore size of the micropores was 100 nm. Since the TEM microgrid 10 in this embodiment is composed only of a carbon nanotube structure, does not contain a metal mesh, and the carbon nanotube structure is relatively pure, and has no interference to the composition analysis of the sample to be tested, thereby effectively eliminating the conventional The metal grid in the micro-grid interferes with the analysis of the components of the sample to be tested, thereby facilitating the accuracy of the composition analysis of the transmission electron microscope 10.

In the present embodiment, when the TEM microgrid 10 is applied, the material sample to be observed is placed in the wafer shape. Nano carbon tube structure surface. When the size of the material sample is larger than the micropores 108 of the wafer-shaped carbon nanotube structure, the micropores 108 in the wafer-shaped carbon nanotube structure can support the material sample. The material sample can be observed through the electron transmissive portion 104 corresponding to the microholes 108. And when the size of the material sample is smaller than the micropores 108 of the disk-shaped carbon nanotube structure, especially when the material sample is a nano particle having a particle diameter of less than 5 nm, the material sample can pass The adsorption of the carbon nanotubes 106 located in the micropores 108 is stably adsorbed on the surface of the tube wall of the carbon nanotubes 106. At this time, the material sample can also be observed through the electron transmissive portion 104 corresponding to the micropores 108. Thus, the TEM microgrid of the present invention can be used to observe a sample of nanoparticle material having a particle diameter of less than 5 nm, thereby eliminating the amorphous carbon film in the conventional microgrid and the nanoparticle having a particle diameter of less than 5 nm. The effect of high resolution image observation by TEM.

Referring to FIG. 6, the present invention further provides a method for preparing the TEM micro-gate, which comprises the following steps:

S1, providing a piece of carbon nanotube structure.

The sheet-like carbon nanotube structure is composed of at least one carbon nanotube film. The carbon nanotube film may be a carbon nanotube film, a carbon nanotube film or a carbon nanotube film. In this embodiment, the sheet-like carbon nanotube structure is formed by laminating (ie, laminating and intersecting) a plurality of layers of carbon nanotube film which are formed from a nano carbon. The tube array is pulled and obtained. The method for preparing the carbon nanotube film comprises the steps of: providing a carbon nanotube array and extracting at least one carbon nanotube film having a certain width and length from the carbon nanotube array.

The carbon nanotube array can be a super-sequential carbon nanotube array. In this embodiment, the method for preparing the carbon nanotube array adopts a chemical vapor deposition method, and the specific steps thereof include: (a) providing a flat substrate, the substrate may be selected from a P-type or N-type germanium substrate, or may be formed. The ruthenium substrate having an oxide layer is preferably a 4-inch ruthenium substrate in this embodiment; (b) a catalyst layer is uniformly formed on the surface of the substrate, and the catalyst layer material may be selected from iron (Fe), cobalt (Co), and nickel (Ni). ) or any combination thereof (c) annealing the substrate on which the catalyst layer is formed in air at 700 to 900 ° C for about 30 minutes to 90 minutes; (d) placing the treated substrate in a reaction furnace in a protective gas atmosphere The mixture is heated to 500-740 ° C, and then reacted with a carbon source gas for about 5 to 30 minutes to grow a super-aligned carbon nanotube array having a height of 200 to 400 μm. The super-sequential carbon nanotube array is a plurality of pure carbon nanotube arrays formed of carbon nanotubes that are parallel to each other and perpendicular to the substrate. The super-sequential carbon nanotube array contains substantially no impurities such as amorphous carbon or residual catalyst metal particles, etc., by controlling the growth conditions described above. The carbon nanotubes in the array of carbon nanotubes are in close contact with each other to form an array by van der Waals force.

In the present embodiment, the carbon source gas may be a chemically active hydrocarbon such as acetylene, and the protective gas may be nitrogen, ammonia or an inert gas.

The step of extracting the carbon nanotube film from the carbon nanotube array by using a stretching tool comprises the following steps: (a) selecting a plurality of carbon nanotube segments of a certain width from the carbon nanotube array. In this embodiment, it is preferred to contact the carbon nanotube array with a tape having a certain width to select a plurality of carbon nanotube segments of a certain width; (b) to stretch at a certain speed along a growth direction substantially perpendicular to the growth direction of the carbon nanotube array. A plurality of carbon nanotube segments are formed to form a carbon nanotube film.

In the above stretching process, the plurality of carbon nanotube segments are gradually separated from the substrate in the stretching direction under the action of the tensile force, and the selected plurality of carbon nanotube segments are respectively separated from the other nanometers due to the effect of the van der Waals force. The carbon nanotube segments are continuously pulled out end to end to form a carbon nanotube film. The carbon nanotube film is a carbon nanotube film having a certain width formed by connecting a plurality of carbon nanotube segments arranged substantially in the stretching direction. The width of the carbon nanotube film is related to the size of the substrate on which the carbon nanotube array is grown. The length of the carbon nanotube film is not limited and can be obtained according to actual needs.

The step of laminating and cross-setting a plurality of carbon nanotube film may specifically include the following steps: First, a substrate is provided. The substrate has a flat surface and the material is not limited. In this embodiment, the substrate can be a ceramic sheet.

Next, the above-mentioned carbon nanotube film is laminated in this order and laid on the surface of the substrate. The stacked and cross-connected, that is, in the laminated carbon nanotube film, the carbon nanotubes in the plurality of carbon nanotube films have an intersection angle α and α is not equal to 0 degrees.

Since the carbon nanotubes are relatively pure and have a large specific surface area, the carbon nanotube film obtained by directly drawing from the carbon nanotube array has good viscosity. The carbon nanotube film can be directly laid on the surface of the substrate or the surface of the other carbon nanotube film. Specifically, the carbon nanotube film may be sequentially disposed on the surface of the substrate. The two adjacent layers of carbon nanotubes are tightly bonded by the van der Waals force.

S2. Laser-perforating the sheet-shaped carbon nanotube structure to form a plurality of electron transmissive portions 104.

In this embodiment, the manner in which the plurality of electron transmissive portions 104 are formed specifically includes the following steps: First, a focused laser beam is provided. The laser beam can be generated by a conventional argon ion laser or carbon dioxide laser. The laser beam has a power of 5 to 30 watts (W), preferably 15 watts.

Next, the focused laser beam is focused and focused on the surface of the sheet-shaped carbon nanotube structure by a point-by-point focus in a predetermined pattern, and the power of the laser beam is adjusted to make the sheet at the position of the focused laser beam. A portion of the carbon nanotubes in the carbon nanotube structure are ablated and the density is lowered to form micropores 108. A portion of the carbon nanotubes 106 remain in the micropores 108, thereby forming a plurality of mutually spaced electron-transporting portions 104 distributed in a predetermined pattern. The plurality of electron transmissive portions 104 are distributed in an array. The amount of the remaining partial carbon nanotubes 106 is preferably such that the sample particles can be better supported.

Specifically, the pulsed laser beam can be selected to form a plurality of micropores 108 on the surface of the sheet-shaped carbon nanotube structure by progressive line-by-point scanning in a predetermined pattern. Specifically, the following two ways can be implemented:

Method 1: Fixing the sheet-like carbon nanotube structure, moving the laser beam, and irradiating the laser beam to the surface of the sheet-shaped carbon nanotube structure according to a predetermined pattern interval.

Method 2: Fixing the laser beam, moving the sheet-shaped carbon nanotube structure, and irradiating the laser beam to the surface of the sheet-shaped carbon nanotube structure according to a predetermined pattern interval.

It will be understood that the above moving and illuminating steps can be controlled by a computer program. The so-called "interval illumination" means that when the sheet-shaped carbon nanotube structure is laser-perforated, the laser beam is intermittently irradiated and irradiated to different positions of the sheet-shaped carbon nanotube structure, the difference The locations are spaced apart to ensure that a plurality of spaced apart apertures 108 are formed in the sheet of carbon nanotube structure. The plurality of microwells 108 are distributed in an array.

When the laser beam is irradiated to the surface of the sheet-shaped carbon nanotube structure at intervals, since the carbon nanotubes in the sheet-shaped carbon nanotube structure have good absorption characteristics to the laser, the sheet is irradiated at the laser irradiation. The carbon nanotube bundle formed by the aggregation of a plurality of carbon nanotubes in the carbon nanotube structure will be first burned by absorbing more heat. Secondly, according to the different power of the laser, the carbon nanotube bundles of different diameters in the sheet-shaped carbon nanotube structure, even a single carbon nanotube, will be burned. The present invention realizes the residual portion of the carbon nanotubes 106 in the formed micropores 108 by adjusting the power of the laser beam to 5 to 30 watts (W). The carbon nanotubes 106 in the micropores 108 can be used to support the sample to be tested and form the electron transmissive portion 104.

S3, cutting the sheet-shaped carbon nanotube structure having the electron-transmissive portion 104 to a predetermined size to form the transmission electron micro-gate 10.

First, a laser beam is provided. In this embodiment, the laser beam can be generated by a conventional argon ion laser or carbon dioxide laser having a power of 5 to 30 watts (W), preferably 18 watts.

Next, the laser beam is focused and irradiated onto the surface of the sheet-like carbon nanotube structure having a plurality of electron-transmissive portions 104 for cutting to form a transmission electron micro-mirror 10 of a predetermined shape and size. The laser beam The surface of the sheet-like carbon nanotube structure can be directly irradiated from the front surface by focusing with a lens. It can be understood that the laser beam can be focused on the surface of the sheet-shaped carbon nanotube structure by vertical irradiation or oblique irradiation. The sheet-like carbon nanotube structure absorbs the energy of the laser beam to react with and decompose the oxygen in the air, thereby forming the sheet-shaped carbon nanotube structure having a predetermined shape and size and other partial sheet-like carbon nanotube structures. disconnect. In this embodiment, after the cutting, a disk-shaped carbon nanotube structure having a diameter of about 3 mm is obtained.

It can be understood that the above cutting step can also be implemented by the method of fixing the sheet-shaped carbon nanotube structure in step 3, moving the laser beam, or fixing the laser beam, and moving the sheet-shaped carbon nanotube structure. In addition, the time during which the laser beam is focused and irradiated in the cutting step may be slightly longer than the time when the laser beam is focused and irradiated during laser drilling of the sheet-shaped carbon nanotube structure to realize the sheet-shaped carbon carbon at the irradiation point. The tube structure is completely separated from other parts of the sheet-like carbon nanotube structure. This embodiment is not limited to the above-described laser processing method, and other methods in the prior art, such as physical or chemical etching, can also be used to cut the sheet-like carbon nanotube structure.

It can be understood that the above steps can realize the rapid mass production of the TEM microgrid 10 by cutting a large-sized sheet-shaped carbon nanotube structure. Specifically, the laser beam may be focused and irradiated to a sheet-shaped carbon nanotube structure having an electron-transmissive portion in a predetermined pattern, and the sheet-shaped carbon nanotube structure is cut to a predetermined size to form a plurality of wafer-shaped naphthalenes. The carbon nanotube structure has a plurality of electron transmissive portions 104 each of the disk-shaped carbon nanotube structures.

The TEM microgrid 10 can be further treated with an organic solvent. The organic solvent is a volatile organic solvent at room temperature, and one or a mixture of ethanol, methanol, acetone, dichloroethane and chloroform may be used. The organic solvent in this embodiment is ethanol. The organic solvent should have good wettability with the carbon nanotube. The step of treating with an organic solvent is specifically: dipping the organic solvent onto the surface of the TEM microgrid 10 through a test tube to infiltrate the entire sheet-shaped carbon nanotube structure, or immersing the TEM microgrid 10 in a container containing an organic solvent. Infiltration. After organic solvent treatment The side-by-side and adjacent carbon nanotubes in the body of the micromirror 10 will gather together and have good mechanical strength. In addition, after the plurality of carbon nanotubes 106 in the micropores 108 are treated with an organic solvent, a portion of the adjacent carbon nanotubes are aggregated into a bundle of carbon nanotubes. A plurality of secondary micropores may be further formed between the plurality of carbon nanotube bundles. The pore size of the micropores may be from 1 nm to 1 μm. It can be understood that the step of the organic solvent can also be performed before the cutting step, that is, the sheet-shaped carbon nanotube structure having the electron-transmissive portion 104 is first subjected to an organic solvent treatment, and then cut into a wafer-shaped nanometer. Carbon tube structure.

The TEM micro-gate provided by the embodiment of the invention and the preparation method thereof have the following advantages: First, the TEM micro-gate is composed of a disk-shaped carbon nanotube structure, no metal mesh is required, and the wafer-shaped carbon carbon The tube structure is relatively pure, which can effectively eliminate the interference of the metal grid in the traditional micro-grid on the analysis of the components of the sample to be tested, thereby facilitating the accuracy of component analysis using the transmission electron microscope. Secondly, the TEM micro-gate provided by the embodiment of the present invention is prepared by performing laser drilling on the sheet-shaped carbon nanotube structure and cutting the sheet-shaped carbon nanotube structure by a predetermined size, without an evaporation process. The preparation method is relatively simple.

In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and it is not possible to limit the scope of the patent application of the present invention. Equivalent modifications or variations made by those skilled in the art in light of the spirit of the invention are intended to be included within the scope of the following claims.

Claims (13)

A method for preparing a transmission electron microstrip, comprising the steps of: providing a piece of carbon nanotube structure; performing laser irradiation on the sheet carbon nanotube structure to make a sheet of carbon nanotubes irradiated by the laser A portion of the carbon nanotubes in the structure are ablated, the density is lowered to form a plurality of electron-transmissive portions, and the sheet-shaped carbon nanotube structure having the electron-transmissive portion is cut to a predetermined size to form the transmission electron micro-gate. The method for preparing a TEM microgrid according to claim 1, wherein the sheet-like carbon nanotube structure is a self-supporting structure composed of a plurality of carbon nanotubes. The method for preparing a TEM micro-grid according to claim 1, wherein the sheet-shaped carbon nanotube structure comprises a plurality of stacked carbon nanotube membranes, wherein the carbon nanotube membrane consists of a plurality of nanocarbons The tube is composed of a plurality of carbon nanotubes arranged in a preferred orientation in the same direction, and most of the carbon nanotubes in the carbon nanotube membrane are connected end to end by Van Valent. The method for preparing a TEM micro-gate according to claim 3, wherein the method for preparing the sheet-like carbon nanotube structure comprises the steps of: providing a carbon nanotube array; directly pulling from the carbon nanotube array Obtaining a plurality of carbon nanotube films; and stacking a plurality of carbon nanotube films on each other. The method for preparing a TEM micro-grid according to claim 1, wherein the step of performing laser drilling on the sheet-like carbon nanotube structure to form a plurality of electron-transmissive portions comprises the following steps: providing a focused ray Beams are irradiated; the focused laser beams are irradiated to the sheet-like carbon nanotube structure line by line at intervals. The method for preparing a TEM micro-grid according to claim 5, wherein each micropore corresponds to one electric power The sub-transmission portion has a plurality of carbon nanotubes in each of the micropores, and the electron transmissive portion is composed of a plurality of carbon nanotubes disposed in the micropores. The method for preparing a TEM micro-gate according to claim 6, wherein a plurality of carbon nanotubes in the micropores are suspended. The method of producing a TEM microgate according to claim 5, wherein the plurality of electron transmissive portions are distributed in an array. A method of producing a TEM microgate according to claim 5, wherein a distance between adjacent electron-transmissive portions is greater than 1 μm. The method for preparing a TEM micro-gate according to claim 1, wherein the step of cutting the sheet-like carbon nanotube structure having an electron-transmissive portion specifically comprises the steps of: providing a focused laser beam; and pressing a predetermined pattern The laser beam is focused and irradiated to a sheet-shaped carbon nanotube structure having an electron transmissive portion, and the sheet-shaped carbon nanotube structure is cut according to a predetermined size to form a plurality of disc-shaped carbon nanotube structures, each circle The sheet-like carbon nanotube structure has a plurality of electron transmissive portions. The method of producing a TEM microgrid according to claim 10, wherein the disk-shaped carbon nanotube structure has a diameter of 3 mm. The method of preparing a TEM micro-gate according to claim 5, wherein the power of the laser beam is 5 to 30 watts. The method for producing a TEM micro-gate according to claim 1, further comprising the step of treating the sheet-like carbon nanotube structure having an electron-transmissive portion with an organic solvent.