JP2009107903A - Method and device for cutting carbon nanotube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device which are suitable for adjusting the length of a carbon nanotube in the order of several tens of nanometers and can cut the carbon nanotube in such a manner that the cylindrical form is kept to the tip part. <P>SOLUTION: One end of a carbon nanotube to be cut is fixed to a base material, and another carbon nanotube is loaded on an electrode. The other end of the carbon nanotube fixed to the base material and the end part of the carbon nanotube loaded on the electrode are brought into contact to each other, and then an electric current or a pulse electric current is applied between the base material and the electrode by the discharge of a capacitor. Thereby, the tip part of the carbon nanotube fixed to the base material is sublimated and cut by Joule heat generated at the contact part of two carbon nanotubes. The length of the carbon nanotube can be finely adjusted in the interval of several tens of nanometers by repeating the cutting. Further, the cylindrical form can be kept to the tip part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a carbon nanotube cutting method and cutting apparatus, and more particularly, to a method and apparatus for sublimating and cutting carbon nanotubes using Joule heat generated by energization.

  Since carbon nanotubes have excellent mechanical and electrical properties, active research is being conducted on scanning probe microscopes, field emission, and field effect transistors. In recent years, carbon nanotubes have been widely used as a probe for scanning probes. The reason is that the radius of curvature of the tip of the carbon nanotube is extremely small, the minimum radius of curvature is about 1 nm, and the rigidity is high, so that the aspect can be increased as a probe.

  Known methods for producing carbon nanotubes include the arc method, the CVD method, and the laser ablation method. Of these, the arc method is the method with the highest crystallinity, and the arc method is the best from the viewpoint of strength for use in the probe of a scanning probe microscope.

  However, a technique for controlling the diameter and length when producing carbon nanotubes by the arc method has not yet been found. Among the scanning probe microscopes, the rigidity of the carbon nanotube probe is very important for the stable measurement of the atomic force microscope (AFM), and it is necessary to control the diameter and length for that purpose. There is.

  Until now, several methods for adjusting the length of carbon nanotubes by processing have been proposed. For example, as disclosed in Patent Documents 1 and 2, there are methods of grinding the tips of carbon nanotubes and cutting with a focused ion beam. In Patent Document 1, a nanotube and a sharp discharge needle are prepared, and a DC voltage or a pulse voltage is applied between the nanotube and the discharge needle to excite discharge to grind the tip shape. A feature of this method is that the nanotubes are sharpened. Moreover, in patent document 2, it cuts by scanning a focused ion beam in a desired location. In this method, it is necessary to consider the irradiation energy of the focused ion beam to the part other than the cutting part in the nanotube, but there is an advantage that cutting can be performed at an arbitrary position. Thus, by adjusting the length of the carbon nanotube, it has been applied as a probe of a scanning probe microscope.

JP 2002-347000 A JP 2005-319581 A

  AFM was mostly used for surface morphology observation and roughness evaluation, but with the advent of carbon nanotube probes, it is also being used for quantitative evaluation of three-dimensional structure height and groove width. . However, in three-dimensional shape measurement, resolution often decreases due to image distortion and noise due to the force acting between the probe and the sample. In the case of a carbon nanotube probe, it is known to be particularly noticeable, and in the case of a sample with large irregularities, adhesion to the side surface due to van der Waals force, probe slip, or the influence on the image by bending is a problem. Become.

  Therefore, it is important to control the rigidity of the probe by the length and diameter in the carbon nanotube probe. For example, when adjusting the length by processing, it is considered that the controllability is sufficiently good if the length is controlled with an accuracy about the diameter of the carbon nanotube, but if the carbon nanotube is sharpened by grinding or cutting, a certain value is obtained. The maximum carbon nanotube probe rigidity to be obtained depending on the length and diameter cannot be secured. Also, if the tip shape varies, the measurement image varies from probe to probe, which is not preferable as an AFM probe for quantitative evaluation. Therefore, in addition to being able to control the length of the carbon nanotube probe with high accuracy, it is considered preferable to maintain a cylindrical shape over the tip of the probe in order to ensure the rigidity of the probe.

  An object of the present invention is to provide a carbon nanotube cutting method and a cutting apparatus that can adjust the length of a carbon nanotube probe tip with high accuracy and can maintain a cylindrical shape up to the tip.

  In the present invention, one end of a carbon nanotube to be cut is fixed to a substrate, the tip of the other end of the carbon nanotube fixed to the substrate is brought into contact with an electrode, and a capacitor is interposed between the substrate and the electrode. A method of cutting a carbon nanotube, characterized by sublimating and cutting the other end portion of the carbon nanotube fixed to the substrate by Joule heat generated at a contact portion of the carbon nanotube by passing an electric current or a pulse current due to discharge is there.

  The present invention also fixes one end of the carbon nanotube to be cut to the base material, prepares another carbon nanotube in addition to this and carries it on the electrode, and the other end of the carbon nanotube fixed to the base material and the electrode The carbon nanotubes fixed to the base material are brought into contact with each other by contacting the tip of the carbon nanotube supported on the substrate and passing a current or pulse current due to capacitor discharge between the base material and the electrode, resulting from Joule heat generated at the contact portion of the two carbon nanotubes. In the method of cutting carbon nanotubes, the tip portion of the carbon nanotubes is sublimated for cutting.

  In this cutting method, it is desirable that the diameter of the carbon nanotube supported on the electrode is larger than the diameter of the carbon nanotube fixed to the substrate. As a result, the carbon nanotubes on the substrate side can be cut more selectively.

  Further, in this cutting method, it is desirable that the carbon nanotubes fixed to the base material and the carbon nanotubes supported on the electrode are fixed by electron beam deposition, thereby improving conduction between the electrode and the base material. Can be easily cut.

  It was found that the carbon nanotube maintained a cylindrical shape up to the tip and the cutting surface became closer to a flat shape by repeating the operation of passing a current or pulse current due to capacitor discharge between the substrate and the electrode a plurality of times.

  In addition, the present invention also has a structure in which one end of a carbon nanotube to be cut is fixed to a base material and the other end is supported by intersecting with an electrode or a carbon nanotube supported on an electrode, and a capacitor discharge is performed between the base material and the electrode. After the carbon nanotube is cut to an arbitrary length by flowing a current or a pulse current, the cut surfaces are brought into contact with each other, and a current or a pulse current caused by capacitor discharge is again flowed to fix the carbon nanotubes to the substrate. There is a carbon nanotube cutting method characterized by sublimating and cutting a tip portion of a nanotube.

  Also in this cutting method, when the cylindrical shape is maintained up to the tip portion and the flat cutting surface is made close to flat, it is desirable to repeat the energization operation performed after cutting the carbon nanotube at an arbitrary portion a plurality of times. In addition, it is desirable to fix the carbon nanotubes to one or both of the substrate and the electrode by electron beam deposition.

  The carbon nanotube cutting device of the present invention includes a pair of electrodes, a capacitor for storing electric charge, a DC power source for storing electric charge in the capacitor, and an electric circuit having a switch for switching between charging and discharging. And In addition, an electric circuit having a pair of electrodes and a pulse application power source or a DC power source for passing a pulse current between the pair of electrodes is provided.

  The carbon nanotube cutting method of the present invention is suitable for adjusting the length of the carbon nanotube probe with high accuracy, and can secure the maximum rigidity to maintain the cylindrical shape up to the tip portion. It is suitable as a thickness adjusting method.

  In AFM measurement using a carbon nanotube probe, image distortion and noise during line and space measurement, and the cause of uncertainty in the edge shape are due to the low bending rigidity of the carbon nanotube probe and the tip shape. This is due to the fact that it varies from probe to probe.

  By performing the cutting method of the present invention while observing in an electron microscope, the carbon nanotube can be shortened to a length of about 50 nm at the minimum, and the bending rigidity can be increased by shortening the length as much as possible. .

  In addition, since a cylindrical shape with a uniform diameter can be maintained over the tip, the maximum carbon nanotube probe rigidity can be ensured, leading to elimination of variations in measurement images for each probe.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same portions are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 1 shows a configuration of a cutting apparatus when a carbon nanotube is cut by flowing a current due to capacitor discharge. The cutting apparatus of the present embodiment includes a pair of electrodes composed of a base material 3 and an electrode 4, a capacitor 6 for storing electric charge, a resistor 7, a DC power source 9 for storing electric charge in the capacitor 6, and charging. And an electric circuit including a switch 8 for switching discharge.

  In the cutting of the carbon nanotube, one end of the carbon nanotube 1 to be cut is fixed to the base material 3, and another carbon nanotube 2 is prepared separately and supported on the electrode 4. This is carried out by bringing the tip of the electrode into contact with each other and flowing a current due to capacitor discharge between the base material 3 and the electrode 4.

  At this time, the contact state at the time of cutting between the carbon nanotube 2 supported on the electrode 4 and the carbon nanotube 1 fixed to the base 3 is such that the tip of the carbon nanotube comes into contact from the front as shown in FIG. As shown in FIG. 4, the tips of the carbon nanotubes may be contacted from an oblique direction. However, the method of adjusting the shape of the tip by butt-cutting the tips as shown in FIG. 5 is most suitable for adjusting to the target length.

  Joule heat is generated at the contact portion between the carbon nanotube 1 and the carbon nanotube 2 due to the current during the capacitor discharge, the portion is instantly sublimated, and cutting of the tip of the carbon nanotube occurs.

  The carbon nanotube 1 can be preferentially cut by making the diameter of the carbon nanotube 2 larger than the diameter of the carbon nanotube 1.

  The capacity of the capacitor 6 is about 0.1 to 100 μF, and the discharge voltage is preferably in the range of 1 V to 10 V, and is preferably changed according to the aspect ratio of the carbon nanotubes 1 fixed to the substrate 3. For example, a carbon nanotube having a diameter of 20 nm and a length of 1 to 2 μm is cut at 2 to 5V. The relaxation time of the voltage due to the capacitor discharge depends on the resistor 7 and the capacitor 6, but there is no particular effect of the relaxation time. At this time, about 2.2Ω is used, and it is sufficient if the rising current value is about several tens to 100 μA. Cutting occurs.

  FIG. 1 shows a state in which the tip portions of the carbon nanotube 1 and the carbon nanotube 2 are in contact, that is, a state before cutting. After cutting, a part of the cutting area disappears as shown in FIG. According to the method of this example, an amorphous region 10 that has been amorphized is obtained over the length from the cutting surface to the thickness of the layer of the carbon nanotube 1, and the diameter of the amorphous region 10 on the center side from the amorphous region is obtained. Becomes a uniform cylindrical shape. Further, the cutting surface of the carbon nanotube 1 was in a state where the hole of the tube was closed.

A conventional method of cutting carbon nanotubes using electric current is performed in a state in which one end of carbon nanotubes is fixed to a conductive base material and the other end is fixed to a conductive base material to ensure electrical contact. It was. By gradually increasing the voltage, evaporation occurs one layer at a time from the outermost layer of the carbon nanotubes. When the current is continued until it is cut, the evaporation time becomes shorter as the inner layer is formed, which sharpens. Since the evaporation time is delayed in each layer, the carbon nanotube cannot be made cylindrical up to the tip, and the tip is never flattened. Although the electron beam cutting is kept cylindrical up to the tip, and the cutting using the focused ion beam is kept up to the tip, there is no guarantee regarding the accuracy of the length of the carbon nanotube cutting pitch. In addition, there is no guarantee regarding the accuracy of the length of the carbon nanotube that is cut once by discharge. In the present invention, the length and the tip shape of the carbon nanotube 1 are determined by repeating the cutting a plurality of times as shown in FIG. Fine adjustment is possible with an accuracy of about 50 nm at a minimum.

  Since the tip of the carbon nanotube 1 after each cutting is made amorphous, when the cutting is performed again, the amorphous portion at the tip is first sublimated. It is possible to cut with a pitch of several tens of nm by this method. By this method, the length of the carbon nanotube can be controlled in a short time. In particular, the present invention is not limited to multi-walled carbon nanotubes having a diameter of about 10 nm to 50 nm, and the cylindrical shape can be maintained up to the tip by applying to single-walled carbon nanotubes.

  As a material of the base material 3, silicon, silicon nitride, metal-coated silicon, or tungsten, which is generally used as a probe holder in a cantilever using a carbon nanotube short needle, can be used. In the case of a conventional cutting method, a semiconductor is not used for the base material and a metal coating or the like is applied, or a metal is used. However, in the cutting method of the present invention, a semiconductor may be used for the base material. Applicable.

  A general carbon nanotube probe cantilever is manufactured by using a probe in a conventional silicon probe cantilever or a tungsten probe cantilever as a holder and fixing the carbon nanotube probe to the holder. Some silicon probes are doped with boron or nitrogen. The shape of these probes is a quadrangular pyramid, a triangular pyramid, or a conical shape. When a cantilever probe having a carbon nanotube probe is cut by the cutting method of the present invention, the holder to which the carbon nanotube probe is fixed can be used as the substrate 3.

  The carbon nanotube 1 is preferably fixed to the base material 3 by a method using electron beam deposition in an electron microscope. A metal coating film is formed on the fixing portion 5 between the carbon nanotube 1 and the base material 3 by decomposing the metal compound gas by electron beam irradiation and depositing the product, and the carbon nanotube 1 is formed on the base material by the metal coating film. 3 to fix the fixed portion 5. As the deposit, tungsten, gold, platinum, or the like can be used.

When tungsten is used as the deposit, the carbon nanotube 1 and the base material 3 are brought into contact with each other, and a gas obtained by heating and vaporizing W (CO) ₆ or WF ₂ is introduced into the sample chamber of the scanning electron microscope having a high degree of vacuum. Then, a gas of W (CO) ₆ or WF ₂ is discharged near the contact portion between the carbon nanotube 1 and the base material 3 using a nozzle, thereby forming an atmosphere of the gas near the contact portion. Thereafter, the contact portion is irradiated with an electron beam to decompose the gas, and deposited tungsten is deposited on the contact portion which is an irradiation region, whereby the fixed portion 5 can be formed using tungsten as a deposit.

  The carbon nanotubes 2 supported on the electrode 4 side can also be fixed by electron beam deposition in the same manner as the carbon nanotubes 1 fixed on the substrate side. FIG. 4 shows an example in which the carbon nanotube 2 is fixed to the electrode 4 by electron beam deposition and the fixing portion 11 is formed.

  When a silicon-based holder is used for the substrate 3, it is desirable to coat the substrate with aluminum as a reflective film in order to prevent charge-up by an electron beam.

  Carbon nanotubes include single-walled and multi-walled carbon nanotubes, carbon nanotubes doped with boron or nitrogen, and the like. There are also nanotubes encapsulating metal atoms and nanotubes with metal atoms and metal fine particles plated on the tips of the nanotubes. The cutting method of the present invention can be applied to any of these carbon nanotubes.

  In the method of this embodiment, the tip of the carbon nanotube can be cut at a pitch of several tens of nanometers. Thus, when used as a probe of a scanning probe microscope, the carbon nanotube probe has a required length. By adjusting and maintaining high bending rigidity, it is possible to secure the maximum carbon nanotube probe rigidity to be obtained with a certain length and diameter by keeping the cylinder shape to the tip, and each carbon nanotube probe The measurement image can be measured with good reproducibility.

  In addition, according to the present example, since carbon nanotubes having a cylindrical shape up to the tip can be obtained, when used in a probe of a scanning probe microscope, fine irregularities on the side surface of an uneven sample are captured more faithfully. It becomes possible.

  FIG. 5 shows a configuration at the time of cutting when a carbon nanotube is cut by flowing a pulse current. The carbon nanotube cutting apparatus according to the present embodiment includes an electric circuit including a pair of electrodes including a base material 3 and an electrode 4 and a pulse application power source 12 that causes a pulse current to flow between the pair of electrodes.

  In addition to the carbon nanotube 1 to be cut, another carbon nanotube 2 is prepared, the carbon nanotube 1 is fixed to the substrate 3, and the carbon nanotube 2 is supported on the electrode 4. Cutting is performed by bringing the tip of the carbon nanotube 1 and the tip of the carbon nanotube 2 into contact with each other and applying a pulse current from the pulse applying power source 12 between the substrate and the electrode.

  At this time, the same effect can be obtained even with a DC power supply capable of instantaneous switching instead of a pulse application power supply.

  At this time, the carbon nanotubes 2 supported on the electrode 4 and the carbon nanotubes 1 fixed to the substrate 3 are in contact with each other at the time of cutting, as shown in FIG. As shown in FIG. 4, the tips of the carbon nanotubes may be contacted from an oblique direction. However, the method of adjusting the shape of the tip by butt-cutting the tips as shown in FIG. 5 is most suitable for adjusting to the target length.

  The pulse voltage may be a value in the range of 1V to 10V, and is preferably changed according to the aspect ratio of the carbon nanotubes 1 fixed to the substrate 3. For example, if the carbon nanotubes 1 have a diameter of 20 nm and a length of 1 to 2 μm. Cut at 2V to 5V. If the current value by applying the pulse is about several tens to 100 μA, the cutting is sufficiently performed. Joule heat is generated at the contact portion between the carbon nanotube 1 and the carbon nanotube 2 due to the current during discharge, and the tip of the carbon nanotube 1 is cut by instantaneously sublimating the entire tube layer. Also in this embodiment, the same effect as in the case of Embodiment 1 using capacitor discharge can be obtained, and there is an advantage that the time for switching between charging and discharging can be shortened.

  Similarly, the carbon nanotube 1 can be selectively cut by making the diameter of the carbon nanotube 2 larger than the diameter of the carbon nanotube 1. The material used for the substrate 3, the method for fixing the carbon nanotube 1 to the substrate 3, etc. can be performed in the same manner as in Example 1. For example, regarding the base material 3, a silicon probe or a tungsten probe doped with boron or nitrogen and having a quadrangular pyramid, a triangular pyramid, or a conical shape can be used. Further, the fixing of the carbon nanotube 1 to the base material 3 can also be performed by a method using electron beam deposition in an electron microscope. The carbon nanotube 2 carried on the electrode 4 side can also be fixed by providing the fixing portion 11 by electron beam deposition, as shown in FIG.

  The cutting method of the present embodiment can be applied to any of single-walled and multi-walled carbon nanotubes, carbon nanotubes doped with boron or nitrogen, carbon nanotubes containing metal atoms, carbon nanotubes plated with metal atoms or metal fine particles at the tips of the nanotubes, etc. Applicable.

  Even in the method of this example, the tip portion of the carbon nanotube can be cut at a pitch of several tens of nanometers by a plurality of times of cutting, so that the carbon nanotube can be adjusted to a required length, and the cylindrical shape is maintained up to the tip. Can do.

  FIG. 6 shows another example in which cutting is performed by passing a current due to capacitor discharge. In this embodiment, one end of the carbon nanotube 1 is fixed to the base material 3 and the other end is supported on the electrode 4, and a current due to capacitor discharge is passed between the base material 3 and the electrode 4, so After cutting into length, the cut surfaces of the carbon nanotubes are cut by bringing the cut surfaces into contact with each other and discharging again.

  At this time, the same effect can be obtained even if the carbon nanotubes to be cut as shown in FIG. 11 intersect with the carbon nanotubes supported by the electrode 4 and are cut as shown in FIG. Particularly in this case, controllability is better because the carbon nanotubes are cut at the contact sites.

  When a current due to capacitor discharge is applied after the cut surfaces are brought into contact with each other, the tips of the carbon nanotubes on both the base material side and the electrode side are instantaneously sublimated, and the lengths of both carbon nanotubes become shorter. The cut surface is an amorphous layer, and the thickness is about the thickness of the carbon nanotube layer, which is several tens of nm. This part is instantly sublimated. Therefore, according to the present invention, it is possible to perform cutting with an accuracy of about several tens of nm.

  In the case of FIG. 6 of the present embodiment, it is only necessary to prepare the carbon nanotube to be cut as the carbon nanotube, and it is not necessary to prepare the second carbon nanotube on the electrode side.

  The material of the base material 3, the method of fixing the carbon nanotubes to the base material and the electrode, etc. can be performed in the same manner as in Example 1.

  FIG. 7 shows another embodiment in which cutting is performed by applying a pulse voltage. In this embodiment, one end of the carbon nanotube is fixed to the base material 3 by the fixing portion 5, the other end is supported on the electrode 4, and a pulse current is passed between the base material 3 and the electrode 4 by the pulse application power source 12, The tip is cut by cutting the nanotube into half lengths, then bringing the cut surfaces into contact with each other and applying a pulse voltage from the pulse application power source 12 again. At this time, the same effect can be obtained even with a DC power supply capable of instantaneous switching instead of a pulse application power supply.

  At this time, the same effect can be obtained even if the carbon nanotubes to be cut as shown in FIG. 11 intersect with the carbon nanotubes supported by the electrode 4 and are cut as shown in FIG. Particularly in this case, controllability is better because the carbon nanotubes are cut at the contact sites.

  Also in this embodiment, it is not necessary to prepare carbon nanotubes other than the carbon nanotubes to be cut. After the cut surfaces are brought into contact with each other, the lengths of both carbon nanotubes are shortened by instantaneously sublimating the tips of the carbon nanotubes on both the base material side and the electrode side. It is also possible to obtain a flat tip surface.

  In this embodiment, the same effect as that of the third embodiment using capacitor discharge can be obtained, and there is an advantage that the time for switching between charging and discharging can be shortened.

  The material of the base material 3, the method of fixing the carbon nanotubes to the base material and the electrode, and the like are the same as in the case of Example 1.

  FIG. 13 shows a configuration of a cutting apparatus when a carbon nanotube is cut by flowing a current due to capacitor discharge. The cutting apparatus of the present embodiment includes a pair of electrodes composed of a base material 3 and an electrode 4, a capacitor 6 for storing electric charge, a resistor 7, a DC power source 9 for storing electric charge in the capacitor 6, and charging. And an electric circuit including a switch 8 for switching discharge.

  The carbon nanotube is cut by fixing one end of the carbon nanotube 1 to be cut to the base material 3, bringing the tip end portion of the carbon nanotube 1 into contact with the electrode 4, and a current caused by capacitor discharge between the base material 3 and the electrode 4. It is done by flowing. At this time, as shown in FIG. 14, the method of adjusting the tip shape by butt-cutting the tips is most suitable for adjusting to the target length.

  Joule heat is generated at the contact portion between the carbon nanotube 1 and the electrode 4 due to the current during capacitor discharge, the portion is instantly sublimated, and the tip of the carbon nanotube is cut.

  FIG. 15 shows a state after cutting. Thus, a part of the carbon nanotube 1 tip cutting region disappears. According to the method of this example, the cut surface of the carbon nanotube 1 was in a state in which the hole of the tube was closed.

  In the present invention, the length of the carbon nanotube 1 can be finely adjusted by repeating the cutting a plurality of times, but from the viewpoint of controllability, a method using carbon nanotubes is preferable. However, since it is not necessary to prepare carbon nanotubes on the electrode 4 side by this method, the time can be shortened.

  The material of the base material 3, the method of fixing the carbon nanotubes to the base material and the electrode, and the like are the same as in the case of Example 1.

The block diagram at the time of the cutting in a 1st Example which flows the electric current by capacitor | condenser discharge and cuts a carbon nanotube. The block diagram after the carbon nanotube cutting in a 1st Example. Schematic of the butting method of carbon nanotube tips in the first embodiment. Schematic of the butting method of carbon nanotube tips in the first embodiment. Schematic of the butting method of carbon nanotube tips in the first embodiment. Schematic which showed the mode at the time of cutting a carbon nanotube in multiple times in a 1st Example. The block diagram at the time of cutting which shows the state which adhered the carbon nanotube to the electrode in a 1st Example. The block diagram at the time of the cutting in the 2nd Example which flows a pulse current and cuts a carbon nanotube. The block diagram at the time of the cutting of the carbon nanotube which showed the other Example which flows with the electric current by a capacitor discharge, and showed cutting. The block diagram at the time of the cutting of the carbon nanotube which showed the other Example which flows by supplying a pulse electric current. The schematic at the time of the cutting | disconnection of the rough carbon nanotube using the electrode carrying | support carbon nanotube in a 3rd Example. The schematic after the cutting | disconnection of the rough carbon nanotube using the electrode carrying | support carbon nanotube in a 3rd Example. The block diagram at the time of the cutting in the 5th Example which flows the electric current by capacitor | condenser discharge and cuts a carbon nanotube. The schematic of the shape of the electrode which contacts the carbon nanotube front-end | tip in a 5th Example. The block diagram after the carbon nanotube cutting in a 5th Example.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Carbon nanotube, 2 ... Carbon nanotube, 3 ... Base material, 4 ... Electrode, 5 ... Fixed part, 6 ... Capacitor, 7 ... Resistance, 8 ... Switch, 9 ... DC power supply, 10 ... Amorphous area | region, 11 ... Fixed part, 12 ... Pulse application power source.

Claims (11)

  A method of cutting carbon nanotubes, wherein one end of a carbon nanotube to be cut is fixed to a base material, the tip of the other end of the carbon nanotube fixed to the base material is brought into contact with an electrode, and the base material and the electrode A current or pulsed current caused by capacitor discharge is passed between and the other end portion of the carbon nanotube fixed to the base material is sublimated and cut by Joule heat generated at the contact portion of the carbon nanotube. Cutting method of carbon nanotube.   A method for cutting carbon nanotubes. In addition to the carbon nanotube to be cut, another carbon nanotube is prepared, one end of the carbon nanotube to be cut is fixed to the base material, and the other carbon nanotube is supported on the electrode. Then, the other end of the carbon nanotube fixed to the substrate and the tip of the carbon nanotube supported on the electrode are brought into contact with each other, and a current or pulse current caused by capacitor discharge is passed between the substrate and the electrode. A method of cutting a carbon nanotube, comprising sublimating and cutting the other end portion of the carbon nanotube fixed to the substrate by Joule heat generated at a contact portion of the carbon nanotube.   2. The carbon nanotube cutting method according to claim 1, wherein a diameter of the carbon nanotube supported on the electrode is made larger than a diameter of the carbon nanotube to be cut.   The carbon nanotube cutting method according to claim 1 or 2, wherein the carbon nanotube to be cut is fixed to the substrate by a coating film.   The carbon nanotube cutting method according to claim 2, wherein the carbon nanotube is supported on the electrode by a coating film.   The carbon nanotube cutting method according to claim 1 or 2, wherein an operation of passing a current or a pulsed current caused by capacitor discharge between the substrate and the electrode is repeated a plurality of times.   A method for cutting carbon nanotubes, wherein one end of a carbon nanotube to be cut is fixed to a substrate and the other end is supported on an electrode or supported in a crossing manner with a carbon nanotube supported on an electrode. A current or pulse current caused by capacitor discharge is passed between the electrodes and the carbon nanotubes are cut to an arbitrary length, and then the cut surfaces are brought into contact with each other, and a current or pulse current caused by capacitor discharge is caused to flow again. A method for cutting carbon nanotubes, comprising sublimating and cutting a tip portion of carbon nanotubes fixed to a material.   8. The carbon nanotube cutting method according to claim 7, wherein an operation of supplying a current or a pulsed current by capacitor discharge is repeated a plurality of times after the carbon nanotube supported on the electrode is cut to an arbitrary length.   8. The carbon nanotube cutting method according to claim 7, wherein the carbon nanotube supported on the electrode is fixed to one or both of the base material and the electrode by a coating film.   A carbon nanotube cutting device comprising a pair of electrodes, a capacitor for storing electric charge, a DC power source for storing electric charge in the capacitor, and an electric circuit having a switch for switching between charging and discharging, A carbon nanotube cutting apparatus, wherein a carbon nanotube is disposed between the electrodes to perform cutting.   A carbon nanotube cutting device comprising an electric circuit having a pair of electrodes and a pulse applying power source or a DC power source for passing a pulse current between the pair of electrodes, and the carbon nanotube is disposed between the pair of electrodes. A carbon nanotube cutting apparatus characterized by performing cutting.

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