JP3973359B2 - Electrostatic nanotweezers and nanomanipulator device using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to nanotweezers that can grasp and release nano-sized materials (hereinafter referred to as nano-materials), and can assemble nano-structures such as nano-sized parts and nano-molecular devices by transporting and controlling nano-materials. The present invention relates to a nanomanipulator device that can be used.
[0002]
[Prior art]
In recent years, technological development is increasingly directed to the extremely small area. For example, there is a demand for the development of innovative manufacturing technologies in the nano-region, such as the creation of new materials and nano-sized parts related to optical and electronic information, and the creation of new bio-related functional materials by the accumulation of cells and proteins.
[0003]
In order to be able to control transport of nanomaterials such as moving and stacking in this way, it is necessary to develop nanotweezers that can grasp and release nanomaterials. The first prototype of this nanotweezer is Philip Kim and Charles M. et al. Published in Science magazine published on December 10, 1999 by Lieber. 6 to 8 are manufacturing process diagrams of the nanotweezers.
[0004]
FIG. 6 is a side view of the front end of the tapered glass tube 80. The front end diameter is about 100 nm, and the rear end diameter (not shown) is 1 mm. FIG. 7 is a completed drawing of the nanotweezers. Two gold electrode films 84 a and 84 b are formed on the peripheral surface of the glass tube 80 via an insulating part 82. The carbon nanotubes 86a and 86b are fixed to the gold electrode film in a protruding manner, thereby completing the nano tweezers 88.
[0005]
FIG. 8 is a schematic diagram for applying a voltage to the nanotweezers. Lead wires 92 a and 92 b are led out from the contact points 90 a and 90 b to the gold electrode films 84 a and 84 b and connected to both ends of the variable DC power source 94. When the voltage of the variable DC power supply 94 is applied, the carbon nanotube 86a is positively charged and the carbon nanotube 86b is negatively charged. By the electrostatic attractive force of these positive and negative charges, the tips of the carbon nanotubes 86a and 86b are closed inside, and the nanomaterial 96 can be sandwiched between them.
[0006]
When the voltage is increased, the carbon nanotubes are further closed, so that smaller nanomaterials can be sandwiched. When the voltage is zero, the electrostatic attractive force disappears, and the state returns to the state of FIG. 7 by the elastic restoring force of the carbon nanotubes 86a and 86b, and the nanomaterial 96 is released. In this way, the nanotweezers 88 can be opened / closed only by controlling the magnitude of the voltage, and this is a revolutionary nanotweezer that can freely hold and release nanomaterials.
[0007]
[Problems to be solved by the invention]
However, this nanotweezer 88 has the following weak points. First, molecules have various shapes, and there are nanomaterials that cannot be reliably grasped by two nanotubes. For example, a flat nanomaterial can be gripped by two carbon nanotubes 86a and 86b, but a spherical nanomaterial or a rod-shaped nanomaterial may be unstable and fall off when gripping two nanotubes.
[0008]
Second, since the glass tube 80 is tapered so that the tip thereof is finely processed to 100 hm, the tip portion is particularly weak and fragile. Third, the gold electrode films 84a and 84b are formed over the entire length of the glass tube 80, and contacts 90a and 90b are provided at the rear end of the glass tube whose diameter is increased, and the power is supplied through the lead wires 92a and 92b. 94. That is, since the lead wire is quite thick, an electrical contact must be provided at the rear end of the glass tube whose diameter has been expanded. For this reason, there are difficulties and inefficiencies in forming the gold electrode film over the entire length of the glass tube.
[0009]
Accordingly, an object of the present invention is to provide a nanotweezer that can securely grasp and control a spherical nanomaterial or a rod-like nanomaterial, provide a nanotweezer that is easy to manufacture and durable, and further This is to realize a nanomanipulator device using tweezers.
[0010]
[Means for Solving the Problems]
The invention of claim 1 comprises three or more conductive nanotubes protruding with a base end fixed to a holder, and lead electrodes connected to at least three of the conductive nanotubes, respectively. The electrostatic nanotweezers are characterized in that a voltage is applied between these lead electrodes and the tips of the conductive nanotubes are provided to be openable and closable by electrostatic attraction.
[0011]
The invention according to claim 2 is a projecting portion projecting from the cantilever, three or more conductive nanotubes projecting with the base end fixed to the projecting portion, and at least three or more conductive members therein Electrostatic nanotweezers comprising lead electrodes respectively connected to the conductive nanotubes, wherein a voltage is applied between the lead electrodes to open and close the ends of the conductive nanotubes by electrostatic attraction. .
[0012]
The invention of claim 3 comprises the electrostatic nanotweezers according to claim 1 or 2 and a three-dimensional drive mechanism for controlling the movement of the electrostatic nanotweezers in the XYZ directions with respect to the sample. A nanomanipulator device characterized in that a nanomaterial is transported and controlled to a sample surface.
[0013]
The invention of claim 4 is the nanomanipulator device according to claim 3, wherein at least one conductive nanotube constituting the electrostatic nanotweezers is used as a probe for a scanning probe microscope.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of an electrostatic nanotweezers and a nanomanipulator device using the same according to the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is a schematic perspective view of an embodiment of an electrostatic nanotweezers according to the present invention. The cantilever 2 includes a cantilever portion 4 and a protruding portion 6 formed at the tip thereof. The projecting end 6e of the projecting portion 6 is formed substantially horizontally, and its peripheral surface is composed of four surfaces including a front end surface 6a, side surfaces 6b and 6c, and a rear end surface 6d.
[0016]
Three electrode films 12, 13, and 14 having a required width are formed on the upper plane and the side surface of the cantilever portion 4, and the terminal ends of these electrode films extend to the tip surface 6a and the side surfaces 6b and 6c of the protrusion 6. It is formed out. Base end portions 8b, 9b, and 10b of the conductive nanotubes 8, 9, and 10 are fixed to the distal end surface 6a and the side surfaces 6b and 6c by coating the coating films 16, 17, and 18, respectively.
[0017]
By this fixing, the conductive nanotubes 8, 9, and 10 are set in an electrically conductive state with the electrode films 12, 13, and 14, respectively. The tip portions 8a, 9a, 10a of the conductive nanotubes 8, 9, 10 protrude below the protruding end 6e of the protruding portion 6, and these tip portions 8a, 9a, 10a constitute the nanotube gripping portion 11, and are made of material. It becomes a work nail that can grasp and release a nanomaterial. In this way, the nano tube tweezers 20 according to the present invention are configured by forming the nanotube gripping portion 11 in the cantilever 2.
[0018]
The electrostatic nanotweezers according to the present invention is characterized in that the nanotube gripping portion 11 is composed of three or more nanotubes. In this embodiment, there are three nanotubes, and the three nails can be held so as to wrap the nanomaterial. In other words, the two nanotubes can only be held in an unstable manner, but by using three nanotubes, it becomes possible to stably hold a nanomaterial of any shape stably. In particular, spherical nanomaterials and rod-shaped nanomaterials can be reliably gripped.
[0019]
A control circuit 21 is connected to the rear ends of the electrode films 12, 13, and 14 of the electrostatic nanotweezers 20 through contacts 12a, 13a, and 14a. The control circuit 21 includes a variable DC power source 22, a ground 24, and a switch 26. The contacts 13a and 14a are connected to the ground side, and the contact 12a is connected to the high potential side. Therefore, the electrode film 12 functions as a positive electrode, and the electrode films 13 and 14 function as a negative electrode.
[0020]
In general, the nanotube includes a conductive carbon nanotube, an insulating BN-based nanotube (boron nitride), a BCN-based nanotube (boron carbonitride), and the like. Since the conductive nanotube used in the present invention may be a nanotube having electrical conductivity, an insulating nanotube whose surface is coated with a conductive nanotube or a conductive material is used. A metal material is mainly suitable for the conductive material for coating.
[0021]
Taking a carbon nanotube as an example of a conductive nanotube, the diameter is about 1 nm to several tens of nm, the length is distributed from the nano order to the micron order, and the aspect ratio (length / diameter) is 1000 or more. Also reach. In addition, since carbon nanotubes have a high degree of flexibility and toughness, they are suitable as materials for grasping / releasing nanomaterials by opening and closing their tips.
[0022]
The cantilever 2 used in the above embodiment is obtained by diverting a cantilever probe used for an atomic force microscope (AFM). This cantilever probe is made of silicon or silicon nitride and processed by using a semiconductor planar technique. Therefore, it is higher in strength and superior in durability than conventional glass products. However, in the present invention, the protruding end 6e of the protruding portion 6 is not sharpened but formed on a flat surface. That is, in the present invention, the protruding portion 6 is not used as a probe, but is used as a holder for fixing conductive nanotubes.
[0023]
In order to form the coating films 16, 17, and 18, the organic gas is decomposed by an electron beam in an electron microscope, and the decomposed deposit is used as the coating film. When the organic gas is a hydrocarbon gas, the coating film is a carbon film, and when the organic gas is a metal organic gas, the coating film is a metal film. In the metal film, the conductivity between the conductive nanotubes 8, 9, and 10 and the electrode films 12, 13, and 14 is ensured.
[0024]
As another method of fixing the nanotube base end portion to the protruding portion, the nanotube base end portion can be fused and fixed integrally with the protruding portion by electron beam irradiation or current heating. If the coating film and fusion are used in combination, the nanotubes can be fixed more strongly, and the nanotubes can be prevented from falling off and the durability of the electrostatic nanotweezers can be improved.
[0025]
FIG. 2 is an explanatory diagram of the operation of the embodiment in which a spherical nanomaterial is held. First, the length of the nanotube 8 is set slightly longer than the other nanotubes 9 and 10, and the tip 8a is arranged so as to protrude downward from the other tips 9a and 10a. The tip 8a of the nanotube 8 is used as a probe, and the location and position of the spherical nanomaterial 28 on the sample surface are detected and confirmed by AFM operation.
[0026]
Next, the nanotube gripping part 11 is moved downward so as to come into contact with the sample surface so that the spherical nanomaterial 28 is included in the central part of the three tip parts 8a, 9a, 10a. When the switch 26 is turned on in this state, a voltage is applied to the tips 8 a, 9 a, and 10 a of the conductive nanotubes 8, 9, and 10 through the electrode films 12, 13, and 14. That is, the tip portion 8a becomes a positive electrode, and the tip portions 9a and 10a become a cathode. Since positive charge is accumulated in the positive electrode and negative charge is accumulated in the negative electrode, both electrodes are bent inward by electrostatic attraction, and the nanotube gripping part 11 grips and closes the spherical nanomaterial 28. When the switch 26 is turned off, the electrostatic attractive force disappears, the nanotube gripping portion 11 is opened by the elastic restoring force of the nanotube, and the spherical nanomaterial 28 is released.
[0027]
FIG. 3 is an operation explanatory view of the embodiment in which a rod-shaped nanomaterial is gripped. First, the tip 8a of the nanotube 8 is used as a probe, and the location and position of the rod-shaped nanomaterial 30 on the sample surface are detected and confirmed by an AFM operation.
[0028]
Next, the nanotube gripping portion 11 is moved downward to contact the sample surface so that the rod-shaped nanomaterial 30 is disposed between the three tip portions 8a, 9a, and 10a. When the switch 26 is turned on in this state and the tip portions 8a, 9a, and 10a are closed by electrostatic attraction, the rod-shaped nanomaterial 30 is gripped from the front and rear. When the nanotube gripping part 11 is moved up in this state, the rod-shaped nanomaterial 30 is reliably lifted as shown in the figure.
[0029]
In the embodiment, the nanotube gripping part 11 of the electrostatic nanotweezers 20 is composed of the three conductive nanotubes 8, 9, and 10. Depending on the shape of the nanomaterial, the nanotube gripping part 11 can also be composed of four nanotubes. Thus, the present invention is an electrostatic nanotweezer characterized by grasping and releasing nanomaterials by opening and closing three or more nanotubes.
[0030]
FIG. 4 is an operation explanatory diagram of a nanomanipulator device using the electrostatic nanotweezers of the present invention. A large number of spherical nanomaterials 28 and rod-shaped nanomaterials 30 serving as materials exist on the surface of the sample 32. First, the raw material nanomaterial is detected by the AFM operation of the electrostatic nanotweezers 20 and is gripped by the nanotube gripping portion 11. Next, the electrostatic nanotweezers 20 are moved in the arrow a direction and the arrow b direction by a three-dimensional drive device (not shown), and the raw material nanomaterial is discharged at a desired position of the nanostructure 34. By repeating these operations, a desired nanostructure 34 can be formed on the surface of the sample 32 using various nanomaterials as raw materials.
[0031]
As described above, the closing operation of the conductive nanotubes 8, 9, and 10 is performed by electrostatic attraction by applying a voltage through the electrode films 12, 13, and 14. Further, the opening operation is performed by the elastic restoring force of the conductive nanotubes by releasing the voltage. The movement control of the electrostatic nanotweezers 20 is realized by a movement control mechanism of an AFM (atomic force microscope).
[0032]
FIG. 5 is a configuration diagram of the movement control mechanism of the electrostatic nanotweezers. In the figure, 32 is a sample, 32a is a sample surface, 36 is a three-dimensional drive device, 38 is a semiconductor laser device, 40 is a reflection mirror, 42 is a two-part photodetector, 42a is an upper detector, 42b is a lower detector, 46 is a Z-axis detection circuit, 48 is a display device, and 50 is an XYZ scanning circuit.
[0033]
The electrostatic nanotweezers 20 is arranged with respect to the sample 32, and the nanotube gripping portion 11 is moved in the Z-axis direction to grip the nanomaterial on the sample surface 32a. Thereafter, the XYZ scanning circuit 50 scans the three-dimensional drive mechanism 36 to move the electrostatic nanotweezers 20 to the position of the nanostructure.
[0034]
In the process of this movement, it is necessary to control the position of the nanotube gripper 11 in the Z-axis direction so that the facing distance between the nanotube gripper 11 and the sample surface 32a is kept constant. For this purpose, the laser beam LB is reflected by the cantilever 2, introduced into the two-divided photodetector 42 via the reflecting mirror 40, and Z-axis control is performed while detecting the deflection to the upper and lower detectors 42a and 42b.
[0035]
The Z position is detected by the Z axis detection circuit 46, the XY position is detected by the XYZ scanning circuit 50, and the position information is displayed on the display device 48. That is, the display device 48 displays an uneven image on the sample surface. Then, after the nanotube gripping portion 11 has moved to the position of the nanostructure, the nanomaterial that has been gripped by opening the nanotube gripping portion 11 is released onto the sample surface 32a. This operation is repeated to assemble the nanostructure.
[0036]
The entire shape of the nanostructure can also be imaged on the display device 48 by performing an AFM operation with one nanotube of the nanotube gripper 11 or with the three closed. Therefore, the nanomanipulator device of the present invention is a nanorobot that can freely construct a nanoworld. This nanomanipulator device can be used in various atmospheres including vacuum and air.
[0037]
In the above embodiment, the necessary number of electrode films are formed on the cantilever as the lead electrode for applying a voltage to the conductive nanotube. As another method, the electrode film and the lead wire can be combined, or the lead electrode can be constituted by only the lead wire. A conductive nanotube such as a long carbon nanotube can be used as a lead wire in a very small portion. The bonding method is optimal for the bonding between the nanotubes. These fusions can be performed by methods such as electron beam irradiation, ion beam irradiation, and electric current heating.
[0038]
The present invention is an electrostatic nanotweezers that can hold nanomaterials by electrostatic force between conductive nanotubes. Therefore, it is effective when the nanomaterial to be grasped is insulative, but there is a possibility of short-circuiting when the nanomaterial is conductive. However, when the surface of the conductive nanotube is covered with an insulating coating, even when the conductive nanomaterial is gripped, the conductive nanotubes do not short-circuit, and thus function effectively as nanotweezers. As the insulating film, a hydrocarbon film can be suitably used, and a film can be formed on the surface of the conductive nanotube by electron beam irradiation. As a matter of course, other known materials and known methods can be used for the insulating film material and coating method.
[0039]
The present invention is not limited to the above-described embodiment, and it is needless to say that various modifications, design changes, and the like within the technical scope of the present invention are included in the technical scope.
[0040]
【The invention's effect】
According to the invention of claim 1, since three or more conductive nanotubes are used as a member for gripping the nanomaterial, not only the flat nanomaterial but also any shape of nanomaterial such as a spherical nanomaterial or a rod-shaped nanomaterial. The substance can be gripped stably and reliably. In addition, since the conductive nanotubes can be opened and closed by electrostatic attraction by applying voltage and elastic restoring force by releasing voltage, the opening and closing operation is simple, and nanomaterials can be easily grasped, moved and released.
[0041]
According to the second aspect of the present invention, it is possible to provide electrostatic nanotweezers that are strong for semiconductor cantilevers used for AFM measurement.
[0042]
According to the invention of claim 3, since the electrostatic nanotweezers is equipped with a three-dimensional drive mechanism for controlling the movement of the electrostatic nanotweezers in the XYZ directions with respect to the sample, the nanomaterial is grasped by the electrostatic nanotweezers and desired It is possible to realize a nanomanipulator device that can be moved to a position and can assemble a nanostructure of an arbitrary shape.
[0043]
According to the invention of claim 4, since one nanotube selected from three or more conductive nanotubes constituting electrostatic nanotweezers is used as a probe for a scanning probe microscope, physical property information on the sample surface is obtained. A nanomanipulator device capable of detection can be realized. In addition, this nanomanipulator device has excellent functions such as finding the position of the nanomaterial on the sample surface, and grasping, moving, and releasing the nanomaterial while checking the shape of the nanomaterial. Have.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of an embodiment of an electrostatic nanotweezers according to the present invention.
FIG. 2 is an operation explanatory view of the embodiment in which a spherical nanomaterial is held.
FIG. 3 is an operation explanatory diagram of the embodiment in which a rod-shaped nanomaterial is gripped.
FIG. 4 is an operation explanatory diagram of a nanomanipulator device using the electrostatic nanotweezers of the present invention.
FIG. 5 is a configuration diagram of a movement control mechanism of electrostatic nanotweezers.
FIG. 6 is a side view of the tip of a tapered glass tube.
FIG. 7 is a completed drawing of nanotweezers.
FIG. 8 is a schematic diagram for applying a voltage to nanotweezers.
[Explanation of symbols]
2 is a cantilever, 4 is a cantilever part, 6 is a protruding part, 6a is a front end face, 6b is a side face, 6c is a side face, 6d is a rear end face, 6e is a protruding end, 8, 9 and 10 are conductive nanotubes, 8a and 9a · 10a is the tip, 8b · 9b · 10b is the proximal end, 12 · 13 · 14 is the electrode film, 12a · 13a · 14a is the contact point, 16 · 17 · 18 is the coating film, 20 is the electrostatic nanotweezers, 21 Is a control circuit, 22 is a variable DC power supply, 24 is a ground, 26 is a switch, 28 is a spherical nanomaterial, 30 is a rod-shaped nanomaterial, 32 is a sample, 32 a is a sample surface, 34 is a nanostructure, 36 is a three-dimensional drive Mechanism, 38 is a semiconductor laser device, 40 is a reflection mirror, 42 is a two-divided photodetector, 42a is an upper detector, 42b is a lower detector, 46 is a Z-axis detection circuit, 48 is a display device, 50 is an XYZ scanning circuit , 80 is gala Tube, 82 is an insulating part, 84a and 84b are gold electrode films, 86a and 86b are carbon nanotubes, 88 is nanotweezers, 90a and 90b are contacts, 92a and 92b are lead wires, 94 is a power source, 96 is a nano material, LB Is a laser beam.

Claims (5)

The base ends of three or more conductive nanotubes are fixed to a holder and protruded, and an insulating coating is provided on at least three conductive nanotubes that are not on the same plane, and the insulating coated conductive nanotubes The electrostatic nanotweezers are characterized in that the electrode is connected to an electrode , a voltage is applied to the electrode , and the tip of the conductive nanotube is opened and closed by an electrostatic force. 2. The electrostatic nanostructure according to claim 1, wherein one of the three or more conductive nanotubes to be opened and closed is a conductive nanotube protruding from the other, and one protruding from the other is used as an AFM probe. tweezers. The electrostatic nanotweezers according to claim 1 or 2, wherein the three or more conductive nanotubes to be opened and closed are closed, and the conductive nanotubes are used as an AFM probe. The electrostatic nanotweezers according to claim 1, wherein conductive nanotubes are used as lead wires. 5. The electrostatic nanotweezers according to any one of claims 1 to 4 and a three-dimensional drive mechanism that controls movement of the electrostatic nanotweezers in an XYZ direction with respect to the sample, and the nanomaterial is sampled with the electrostatic nanotweezers. Nanomanipulator device characterized in that conveyance control is performed on the surface.

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