JP2003337099A - Probe using nanotube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a nanotube probe capable of easily grasping the time of replacing the nanotube probe by detecting the exfoliation of a nanotube from a base probe. <P>SOLUTION: The shape of the tip of the base probe is not sharpened. A nanotube probe is constituted by fixius the nanotube to the tip of the probe. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a probe using a nanotube, and more particularly to a shape of a base probe for fixing a nanotube and a method for realizing the shape.

[0002]

2. Description of the Related Art In recent years, nanotubes have been used in various fields due to their unique characteristics. As one of the usages, a probe for a scanning probe microscope (Japanese Patent Laid-Open No. 2000-34678)
6, JP-A-2001-198900). This is a method of attaching a nanotube to a commercially available probe for a scanning probe microscope and observing various physical quantities (eg surface shape, surface potential) of the sample surface with high positional resolution and improving durability. Is. Since the radius of the tip of the nanotube can be processed to about 1 nm and it can be processed into a high aspect shape, high resolution can be realized, and since it is excellent in impact resistance and durability, it is a scanning probe microscope. It is being widely used as a probe for the.

The nanotube probe is an excellent probe as described above, but there are problems. For example, in order to fix the nanotube and the base probe, it is common to attach carbon generated by electron beam irradiation as a binder,
When a strong shock is applied to this part, the nanotubes are separated from the base probe, and the role of the nanotube probe cannot be fulfilled. However, it is very difficult to determine whether the exfoliation of the nanotube has occurred, and the timing of replacement is not clear.

This is because the tip of a commercially available probe, which is the base, is sharpened, and even if the nanotubes are peeled off, physical quantities such as the surface shape can be observed depending on the sample, and the fact is unknown to the user. . In other words, it is difficult to determine because even if it is peeled off, it can be observed with a reasonable resolution. The only way to determine whether the nanotubes are exfoliated is to observe the standard sample for measuring the resolution, or observe the probe with an electron microscope to confirm the presence of the nanotube at the tip of the nanotube probe. However, these methods require a standard sample and an electron microscope apparatus, and require a lot of labor and time.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional nanotube probe, and specifically, to detect the exfoliation of the nanotube from the base probe, (EN) Provided is a nanotube probe needle which can easily grasp the replacement time of

[0006]

Therefore, as a result of earnest research, the present inventors have made the above problems by blunting the tip of a probe for a scanning probe microscope and fixing a nanotube to the tip of the probe. The inventors have found that they can be solved and completed the present invention. That is, the present invention relates to the following (1) to (6). (1) A nanotube probe, characterized in that the tip of the probe serving as a base is not sharpened and a nanotube is fixed to the probe. (2) The nanotube probe according to (1) above, wherein the tip of the probe serving as a base has a spherical shape. (3) The nanotube probe according to (1) above, wherein the tip of the probe serving as a base has a planar shape. (4) The nanotube probe according to the above (3), wherein the plane is inclined with respect to a plane perpendicular to the axis of the probe (5) The nanotube probe is a probe for a scanning probe microscope. The nanotube probe needle according to any one of (1) to (4) above, characterized in that (6) A probe that has a non-sharpened tip shape and serves as a base for immobilizing nanotubes. (7) Ion-irradiate the tip of the base probe,
The method for manufacturing a base probe according to (6) above, which is characterized by molding. (8) The manufacturing of the base probe according to claim 7, wherein the ion irradiation is performed in an oblique and constant direction with respect to the base probe from a position where the front end of the probe serving as the base is displaced. Method.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention provides a nanotube probe needle for a scanning probe microscope in which the tip of a base probe is made blunt and a nanotube is fixed to the tip. The nanotube used in the present invention may be made of carbon or boron nitride. Further, in recent years, there are nanotubes containing metal atoms and nanotubes carrying metal atoms or metal fine particles at the tip of the nanotube. In the present invention, however, such various nanotubes can be used, and the nanotube material is limited. It is not something that will be done.

That is, in general, a probe having a nanotube fixed to its tip, a so-called nanotube probe, has a high durability of the nanotube and a diameter of about 1 nm and is very thin, and the physical quantity of the sample surface can be observed with high positional resolution. Although it is a probe (Japanese Patent Laid-Open No. 2000-346786, Japanese Patent Laid-Open No. 2001-198900) that takes advantage of the characteristics that it is possible and has a high aspect ratio, the present invention changes the shape of the probe to which the nanotube is fixed. However, since it does not affect the characteristics of the nanotube itself in the nanotube probe at all, the type of nanotube fixed to the probe is not particularly limited.

The nanotube probe needle, as shown in FIG.
One in which a nanotube 3 is fixed to a cone-shaped base probe 2 attached to a cantilever 1 of a scanning probe microscope, or one in which a nanotube 3 is fixed to the tip of a metal needle base probe 4 as shown in FIG. Is. FIG. 3 is an enlarged view of the tip of a conventional nanotube probe, in which the tip of the base probe 3 is sharpened, and the nanotube 3 and the base probe 5 are fixed by a binder 6 generally made of deposited carbon. ing. The adhesion between the nanotube and the base probe is carried out, for example, by observing the tip of the nanotube and the base probe under an electron microscope, supplying a hydrocarbon gas to the contact portion, and irradiating the electron beam with the electron beam. Amorphous carbon is deposited and bonded by energy.

On the other hand, FIG. 4 shows an example of the nanotube probe according to the present invention and is an enlarged view of the base probe. As described above, the nanotube probe needle according to the present invention is characterized by the shape of the tips of these pyramids and metal needles (base probe) that fix the nanotubes. The tip of the base probe is blunted, and the nanotube is fixed to this tip. In this example, the tip of the base probe 7 has a spherical shape, and the nanotube 3 is adhered and fixed by the deposited carbon 6. The adhesive fixing method is based on the above conventional means.

The degree to which the tip of the base probe is made blunt depends on the sample. For example, when a metal surface is to be observed, the tip of the base probe 7 has a radius of curvature of 5 nm or more, or is attached. It is desirable that the diameter is at least 3 times the diameter of the nanotube. The method for blunting the tip is not particularly limited, but a molding method by ion irradiation is preferable,
For example, there are methods such as an ion bombardment method and a reactive ion etching method in which atoms are ionized and applied to the tip of the probe to make the tip blunt, which is an inexpensive and simple method. Further, the tip shape of the base probe does not have to be a hemispherical shape having a radius of curvature, and can be formed into various spherical shapes.
Furthermore, the tip shape of the base probe does not have to be a spherical shape, and a tip shape on a plane does not pose any problem. Figure 5
FIG. 4 is another enlarged view of the base probe portion showing another example of the nanotube probe needle. In this nanotube probe needle, the tip portion of the base probe needle 8 is processed into a planar shape by a focused ion beam method or the like. After that, the nanotube 3 is bonded and fixed with carbon 6. Furthermore, FIG.
As shown in FIG. 6, by irradiating the ions 9 in a fixed direction from a position obliquely below the tip side of the base probe 5 rather than from the front side of the tip, a vertical surface with respect to the axis of the probe (shown by a dotted line in the figure). It is also effective to form a flat surface 12 that is inclined with respect to 11. Thereby, the nanotube is further stably attached to the base probe. That is, for example, as described above, when the tip has a spherical shape, the binder cannot be attached to the spherical portion of the tip of the base probe, so that the nanotube cannot be fixed at the tip of the base probe, and the nanotube is lengthened accordingly. However, there is a tendency that the retention and rigidity of the nanotube probe needle become low. On the other hand, when the tip shape of the base probe is molded as shown in FIG. 6, the nanotube 3 can be fixed to the tip of the base probe 10 with the binder 6, so that a more stable nanotube probe can be provided. .

Further, the shape of the tip in the present invention is not limited to these, and for example, a tip having a multi-faced structure does not cause any problem. That is, in the present invention, when the nanotubes are separated from the base probe, the tip of the base probe is blunted, and the effect thereof is extremely reduced in position resolution and unobservable. For example, when the nanotube is peeled from the base probe during observation of the surface shape of the sample, it can be seen that the observation image becomes unclear or unobservable, and therefore the nanotube probe is peeled off. When such a phenomenon is observed, the nanotube probe needle may be replaced with a new one, and the replacement time becomes clear.

Therefore, in view of such a principle of the present invention, the tip shape of the base probe is not limited to a particular shape, and the exfoliation of the nanotube can be identified by the influence on the observed image. Any non-sharpened shape may be used.

Further, in the present invention, by blunting the tip of the base probe, another effect can be obtained. That is, for example, there is strong contact between the nanotube probe and the sample surface, and when the nanotube probe is subjected to a mechanical shock, the nanotube itself is not destroyed, and fracture occurs at the sharpened tip of the base probe. However, although the function of the nanotube probe may be hindered, according to the present invention, since the tip of the base probe is not sharpened, it is possible to prevent the destruction of the tip of the base probe. it can.

[0015]

Example 1 A commercially available silicon probe for a scanning atomic force microscope (manufactured by Olympus Optical Co., Ltd.) was used as a base probe. Before mounting the nanotubes
Ion etching was performed with argon ions using a reactive ion etching device to blunt the tip. After that, while observing the probe and the nanotube with an electron microscope, the nanotube was fixed to the base probe to manufacture a nanotube probe. FIG. 7 is an electron micrograph of the tip of this nanotube probe. The length of the nanotube is 18
It can be seen that the diameter is 0 nm, the diameter is 15 nm, and the radius of curvature of the tip of the base probe is 60 nm.

A gold vapor deposition film was observed with this nanotube probe. The result is shown in FIG. The surface shape of the vapor-deposited gold film is clearly observed, which indicates that the nanotube probe is normal. After this observation, the sample was moved to another part of the sample, the sample and the nanotube probe were brought into strong contact with each other, and the nanotube was separated from the base probe. Using the probe, the surface shape at the same place as in FIG. 8 was observed. The results are shown in Fig. 9. According to this, the observed image is clearly unclear, which is due to the exfoliation of the nanotubes.

In order to further confirm this, after the observation image of FIG. 9 was obtained, the tip of the probe used was observed with an electron microscope. The result is shown in FIG. Obviously, there was no nanotube at the tip of the base probe, and it was confirmed that the observation result of FIG. 9 above shows the exfoliation of the nanotube. Further, since the radius of curvature of the tip of the base probe is about 60 nm, it can be seen that the base probe is not broken despite being strongly contacted with the sample and receiving a mechanical shock.

【The invention's effect】

As described above, the present invention provides a nanotube probe in which a nanotube is attached to the tip of a base probe having a blunt tip. As a result, when the nanotubes are peeled off, the position resolution of the observed image on the sample surface is extremely deteriorated, so that the nanotubes are peeled off and the replacement time of the nanotube probe is clarified. Further, by making the tip of the base probe blunt, it is possible to exert an effect that it is resistant to mechanical shock and is not easily broken.

[Brief description of drawings]

FIG. 1 is a schematic view of a nanotube probe in which a nanotube is fixed to a conical body at the tip of a cantilever.

FIG. 2 is a schematic view of a nanotube probe having a nanotube fixed to the tip of a metal needle.

FIG. 3 is an enlarged view of a conventional nanotube probe needle.

FIG. 4 is an enlarged view of a nanotube probe in which a nanotube is fixed to a base probe whose tip is formed into a spherical shape in the present invention.

FIG. 5 is an enlarged view of a nanotube probe in which the tip of the base probe is formed in a planar shape in the present invention.

FIG. 6 is an enlarged view of a nanotube probe needle formed into a planar shape in which the tip of the base probe needle is tilted in the present invention, and a diagram showing a producing means thereof.

FIG. 7 is an electron micrograph before using the nanotube probe in the present invention.

FIG. 8 is a photograph in which the nanotube probe observed in FIG. 7 is attached to a scanning atomic force microscope and the surface shape of a gold vapor deposition film is observed.

FIG. 9 is a photograph of the same place as in FIG. 8 observed after peeling the nanotube from the nanotube probe of the present invention.

10 is an electron micrograph of the probe used for the observation of FIG.

[Explanation of symbols]

1, cantilever 2, cone 3, nanotube
4, a metal needle 5, a base probe (indicating a cone at the tip of a cantilever or a metal needle tip) 6, a binder 7, a blunted base probe 8,
Base probe with a flat tip, 9 ion irradiation direction, 1
0, a probe whose tip is formed into an oblique plane, 11, a vertical plane with respect to the axis of the base probe, 12, a plane inclined with respect to the vertical plane

Claims (8)

[Claims] 1. A nanotube probe, characterized in that a tip of a probe serving as a base is not sharpened and a nanotube is fixed to the probe. 2. The nanotube probe according to claim 1, wherein the tip of the probe serving as a base has a spherical shape. 3. The nanotube probe according to claim 1, wherein the tip of the probe serving as a base has a planar shape. 4. The nanotube probe according to claim 3, wherein the plane has a shape inclined with respect to a plane perpendicular to the axis of the probe. 5. The nanotube probe according to claim 1, wherein the nanotube probe is a probe for a scanning probe microscope. 6. A probe that has a non-sharpened tip shape and serves as a base for immobilizing nanotubes. 7. The method of manufacturing a base probe according to claim 6, wherein the tip of the probe serving as a base is irradiated with ions to be molded. 8. The base probe according to claim 7, wherein the ion irradiation is performed obliquely and in a constant direction with respect to the base probe from a position where the front surface of the tip of the base probe is displaced. Manufacturing method.