JP3259844B2 - Anisotropic nanocomposite and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anisotropic nanocomposite having a non-linear optical effect, a polarization characteristic, a photovoltaic effect, and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Composite materials in which nanometer-order structural units (metal particles, semiconductor microcrystals, and the like) are dispersed have been studied for applications utilizing nonlinear optical effects and polarization characteristics.

Here, the nonlinear optical effect refers to the following phenomenon. When an electric field E and light having a frequency ω enter a substance,
A polarized wave in which positive and negative charges having a frequency ω induced in proportion to the electric field E are separated in the substance, that is, a polarized wave is generated,
This serves as a wave source to generate light having a frequency ω. This is the normal interaction between light and a substance, and the incident light and the output light have the same frequency. However, depending on the substance, the electric field E,
Sometimes polarized waves induced in proportion to the electric field E ⁿ with respect to the incident light of frequency [ω is quite strongly generated. Such a substance is called a nonlinear optical medium. In this case, light having n times the frequency of the incident light (light having a different color from the incident light) is generated, or the refractive index is changed by the square of the light intensity (electric field). A phenomenon occurs. These are collectively called nonlinear optical effects. The nonlinear optical effect is being studied for application to wavelength conversion of laser light and optical logic elements. Such a nonlinear optical effect is closely related to the quantum confinement effect described below. In other words, when the size of metal or semiconductor fine particles becomes on the order of nanometers (hereinafter referred to as nanoparticles), quantum particles in a substance related to the interaction between light and a substance, such as electrons, holes, excitons, etc. The free behavior of the person is hindered, and a peculiar phenomenon different from the bulk state occurs. This is called the quantum confinement effect. It is known that when such a quantum confinement effect occurs, a strong nonlinear optical effect appears. Therefore, a medium in which fine particles are dispersed as described above and a substance having a structural characteristic on the order of nanometers are regarded as promising as a nonlinear optical material, and are being studied.

[0004] For example, a nanoparticle-dispersed composite material having a nonlinear optical effect is produced by mixing glass and a nanoparticle raw material and dissolving them, and then re-heating at an appropriate temperature to precipitate the nanoparticles in the glass ( NEW GLASS
Vol. 3, No. 4, 41 (1989)), or when glass and a nanoparticle raw material are simultaneously vapor-deposited and both substances are deposited on a substrate, nanoparticles may be precipitated in a thin film made of glass. For example, nanoparticle-dispersed composite materials are manufactured by combining reheat treatments. (Optical Technology Contact Vol. 27, No.
7 389 (1989)).

[0005] In such a medium in which structural units on the order of nanometers, for example, fine particles are dispersed, a strong nonlinear optical effect as a whole is obtained as long as the nonlinear optical effects exhibited by the fine particles do not act to reinforce each other. Not expressed. For example, in a nanoparticle-dispersed composite material manufactured by the above-described method, the size of the nanoparticles varies widely and the crystal axes are not uniform. For this reason, the characteristics such as the nonlinear optical effect also vary (supervised by the Research and Development Bureau, Research and Development Bureau, Science and Technology Agency; Survey on measurement, evaluation and control technologies ”).

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a composite material in which at least one or more substances of the order of nanometers are dispersed in a large number at equal intervals in the orientation direction, and a method for producing the same.

[0007]

Means for Solving the Problems (Constitution of the First Invention) The present invention comprises a substrate and a film formed on the substrate,
The membrane is composed of at least one type of nanoparticles,
The element rises from the surface of the substrate, and the short diameter portion of the cross-sectional shape
The average of the distance (thickness) is between 1 and 9 nm and the major axis
When the average of the distance (length) of the part is between 10 and 90 nm,
The nanoparticles are mutually anisotropic in the direction of the major axis
Orientation and in the direction of the major axis and the minor axis
The present invention relates to an anisotropic nanocomposite material characterized by being dispersed with gaps .

[0008] (Configuration of Second Invention) The present invention, the vacuum container odor Te, 3 to the surface normal of the base plate
Anisotropically depositing one substance from a direction centered on a direction inclined from 0 to 89 degrees and another substance from a direction centered on a direction different from the direction by 30 degrees or more on the substrate surface at the same time. The present invention relates to a method for producing a nanocomposite material.

(Effect of the first invention)

The nanocomposite material according to the present invention comprises at least one kind of fine substance (nanoparticles) on the order of nanometers.
Are dispersed in a three-dimensional area (three-dimensional space) at intervals, and their materials are anisotropic (distances differ in the direction of their cross-sectional shapes) and their arrangement directions are aligned (one).
Orientation), so that nonlinear optical effects based on nanoparticles can be emphasized. As a result, it can be used as a highly efficient material such as optical bistability and phase conjugate wave generation.

[0010] The composite material exhibits excellent polarization characteristics.
In conventional (wire) grid polarizers composed of parallel-arranged conductor wires, when the distance between the wires is shorter than the wavelength of the incident light, the wire acts as a polarizer, and the polarized component parallel to the wires is reflected, The principle that a vertically polarized light component is transmitted is used. However, the distance between the wires is at most several hundred nm by using a holographic exposure method and an ion beam etching method in which interference fringes formed by two-beam interference of a laser are recorded on a photoresist.
It is on the order, and the wavelength range that can be used is up to the near infrared region, and it is difficult to make it into the visible light region. Since this composite material has a structure on the order of nanometers, it can be used as a polarizing plate that can be used for shorter wavelengths based on the same principle as a grit polarizer.

In addition, the thickness of the nanometer order 2
When the nanocomposite material according to the present invention is constituted by using different kinds of semiconductors, flat nanometer-order anisotropic particles alternately and closely constitute a photovoltaic element, and a fine heterojunction solar cell is produced. An effect as if innumerable connected in series is produced, and a high-output solar cell that can generate a large voltage without reducing the current output can be configured. In addition, the present composite material can also exhibit birefringence. (Effect of the second invention)

According to the production method of the present invention, an anisotropic nanocomposite material in which a large number of particles having anisotropy in the order of nanometers having anisotropy, which has heretofore been impossible, is dispersed in a large number with orientation. Can be manufactured. In addition, the present production method is simple, since an anisotropic nanocomposite material can be formed at the time of depositing a film from a gas phase on a substrate without complicated steps. In addition, the area can be increased.

Embodiment (Specific Example of First Invention)

A specific example of the first invention will be described. The anisotropic nanocomposite according to this example uses at least one or more substances. The organization
Inorganic oxides (MgO, Al ₂ O ₃ , SiO, S
iO ₂ TiO ₂ , V ₂ O ₅ , CuO, ZnO, Ge
O ₂ , ZnO ₂ , Nb ₂ O ₅ , MoO ₃ , In ₂ O ₃ ,
SnO ₂ , HfO ₂ , Ta ₂ O ₅ , WO ₃ , Bi
₂ O ₃ , La ₂ O ₃ , CeO _2, etc.) Fluoride (CaF
₂ , CeF ₂ , MgF ₂ etc.), semiconductors (CdS, CdS
e, CdTe, GaAs, Ge, ZnTe, ZnS
Etc.), metals (Fe, Co, Ni, Au, Ag, Al, P
t, Ca, etc.). Usually, two kinds of substances having these compositions are used in combination as exemplified below. When one substance is an oxide or a fluoride and the other substance is a semiconductor or a metal. A composite material having such a composition exhibits a nonlinear optical effect and the like. One substance is a semiconductor and the other substance is also a semiconductor, but a semiconductor different from the first substance. The composite material having such a composition can be used as a photovoltaic element or the like. One substance is an oxide or fluoride and the other substance is a metal. The composite material of this combination can be used as a polarizing plate or the like. One substance is an oxide or a fluoride, and the other substance is the same oxide or fluoride as the one substance, but is different from the one used as the one substance. A composite material in which a large number of two types of nanometer-order substances having such a composition are dispersed in a three-dimensional region exhibits birefringence and can be used for a phase plate or the like.

Further, the material is formed on the substrate surface
You. The form of this substance is anisotropic, its dimensions are:
Thickness, ie the dimension of the short side of the cross section cut parallel to the substrate
The average is between 1 and 9 nm and the length is cut parallel to the substrate
It is necessary that the average of the long side dimensions of the cut cross section is between 10 and 90 nm . In addition, this anisotropic substance must have a uniform orientation direction. If they are not oriented, the polarization characteristics and the nonlinear optical effect cannot be exhibited.
A typical example of the structure is schematically shown in FIGS.
To 10, and shown in FIG.

FIG. 1 shows that two kinds of substances (expressed by a black portion 2 and a white portion 3 forming nanoparticles ) are closely dispersed in a large number, and the average thickness of the nanoparticles in the black portion is several. nm, and the average length is several tens of nm. 1 is a substrate.

FIG. 2 shows the average number of thicknesses n for forming nanoparticles .
m, the average length is several tens of nm, and the height is such that a large number of substances from the substrate surface to the film surface are dispersed via voids . Nanoparticles
However, this is the case where two types of plate-like substances are bonded to face each other.

FIG. 3 shows the average number n of the nanoparticles forming the nanoparticles .
m, an average length of 10 nm, and a height in the case where a large number of substances from the substrate surface to the film surface are dispersed with a part of the materials being in close contact with each other and being inclined with respect to the substrate surface normal. In addition, each nanoparticle
Is a pair of two types of plate-like substances that are bonded together facing each other, and an interval is formed between nanoparticles composed of a pair of substances that are adjacent in the length direction.

[0018] Figures 8-10 and 13, is shown the structure of the film surface, Na appear as relatively darker portion
Particles and nanoparticles that appear as relatively bright parts alternately fill the substrate surface. Each region composed of each nanoparticle has various shapes, and when those shapes are averaged as a whole, the average thickness extended in the vertical direction is several n.
m, the average length is several tens nm. In addition, when each of the regions is individually captured, most of the shape has an average thickness of several nm and an average length of several tens nm.

A specific example which further embodies the second invention will be described.

The method for producing an anisotropic nanocomposite according to this example is carried out using an apparatus as shown in FIG.

The substrate 1 is placed substantially at the center of the vacuum container 8. The substrate is appropriately heated by the heating device 11.
The deposition of a substance with a composite structure on the order of nanometers
This is performed by the small sputter evaporation sources 4 and 7.

The small sputter evaporation source 4 has a surface normal 2
A small sputter evaporation source is installed in a direction 30 inclined at 30 to 89 degrees with respect to 0, differs from the direction 30 by 30 degrees or more in the in-plane direction of the substrate, and is inclined at −89 to 89 degrees with respect to the substrate surface normal 20. 7 is installed. For example, the sputter evaporation source 7
Is installed on a plane extending in the direction 30 from the surface normal 20 of the substrate, at an angle of 0 to 89 degrees with respect to the substrate surface normal 20 on the side opposite to the sputter evaporation source 4. By performing discharge in both sputter evaporation sources, a three-dimensional substance is simultaneously deposited on the substrate surface from the target 12,
Form a film. By changing the input power ratio of the sputter evaporation sources 4 and 7, the thickness can be changed without changing the number density of the substance having a composite structure on the order of nanometers formed. Further, by changing the ratio of the power supplied to the two evaporation sources, the inclination angle of the deposition material can be changed. At this time, if the substrate surface normal is inclined in a plane extending in the direction 30 from the substrate surface normal 20 without changing the angle between the two sputter evaporation sources, the inclination angle of the nanometer-order composite structure can be made zero. it can.

The substrate has the lower melting point of the two kinds of deposition materials.
Heat to 1/3 or less. Heating at a high temperature within this range makes it easier for the deposited material to move on the substrate, and that materials on the order of nanometers are more likely to be in close contact with each other. Conversely, when vapor deposition is performed at a low temperature, the number of voids increases as shown in FIG.

When the same material is vapor-deposited from both sputtering evaporation sources, a structure in which a large number of nanometer-order materials are dispersed through voids from the material as shown in FIG. (Example 1)

An anisotropic nanocomposite according to the present invention was manufactured and its properties were examined.

The anisotropic nanocomposite was manufactured using the apparatus shown in FIG. Substrate 1 provided at the center in decompression container 8
SiO ₂ in a direction 30 inclined 70 degrees with respect to the surface normal 20 of
A small sputter evaporation source 4 equipped with a target is installed,
A small sputter evaporation source 7 on which a CdTe target is mounted is installed in a direction 6 inclined 70 degrees to the opposite side to the direction 30 with respect to the surface normal 20 of the substrate on the plane between 20 and 30. The Ar concentration in the closed vessel was set to 5 × 10 ⁻³ mmHg, and discharge was started from both sputtering evaporation sources. The input power to the SiO ₂ target was 220 W, the input power to the CdTe target was 180 W, deposition was performed for 10 minutes, and SiO ₂ and CdT were deposited on the substrate surface heated to 150 ° C. by the heating device 11.
e was co-evaporated.

When the formed film was observed with a scanning electron microscope (SEM) and a transmission electron microscope (TEM), an anisotropic nanocomposite structure was formed, which is schematically shown in FIG. The part shown in black is flat, the average thickness is 3 nm,
The average width is 20 nm and the height is about 500 nm, and penetrates the entire film thickness. This black substance was oriented at right angles to the incident direction, and was inclined 6 degrees toward the evaporation source 4 with respect to the normal to the substrate surface.

When the composition was examined by X-ray diffraction from the film surface, a diffraction line corresponding to CdTe was detected.

Probe light was incident on the surface of the anisotropic nanocomposite material, and the light absorption spectrum was measured as linearly polarized light. FIG. 5 shows the results. The polarization direction of the probe light and C
The transmitted light intensity is curve 1 when the orientation directions of the substances existing in the three-dimensional region made of dTe coincide, and the transmitted light intensity is curve 2 when they are orthogonal. Curve 3 shows the absorption spectrum of the CdTe polycrystal for comparison.

As is clear from the figure, curve 1 is close to curve 3 of the polycrystal, but the absorption edge of curve 2 is shifted to a higher energy side than that of curve 1. This reflects the anisotropy of the quantum confinement effect by the anisotropic nanocomposite structure according to the present embodiment. As described above, since the dimensions of the anisotropic nanocomposite material are almost uniform and the directions of the crystal axes are uniform, it is possible to develop a high-efficiency nonlinear optical effect. Since there was almost no phase difference between the harmonics generated from the, the harmonics could be generated with high efficiency. (Example 2)

The present embodiment shows an example in which an anisotropic nanocomposite material is applied to an optical polarizing plate, that is, a basic optical element for extracting linearly polarized light from randomly polarized light.

Using the same apparatus as in Example 1, an SiO ₂ target was used for the small sputter evaporation source 4, an Al target was mounted on the small sputter evaporation source 7, the power supplied to both targets was 200 W, and the substrate was cooled to room temperature. SiO ₂ and Al were co-deposited on the substrate under the same conditions as in Example 1 except that the temperature was kept.

The structure of the formed film was determined by SEM and TE
When examined by M, it had an anisotropic nanocomposite structure, and the structure is schematically shown in FIG. The structure has an average thickness of 5 nm, an average length of 30 nm and a height of about 1,500
A substance extending from the substrate surface to the film surface in nm was present in a three-dimensional region, and the substance was dispersed in large numbers through voids having an average width of 5 nm. Each of this material is a plate-like Si of approximately the same thickness.
O ₂ and Al are bonded together. Also, they are oriented in a direction perpendicular to the incident direction. Since the material of the anisotropic nanometer order is oriented, it showed excellent polarization characteristics with respect to visible light.

Conventionally, as a polarizing plate, a film of a polymer such as polyvinyl alcohol is pulled in one direction, the diameter of which is less than nm, and this polymer is oriented in a random direction. And dyed with a dichroic dye such as iodine or methylene blue and affixed to a glass or plastic plate (dichroic polarizer). This dichroic type polarizer has not so good polarization characteristics, is weak to heat, and has a problem peculiar to the resin such as ultraviolet ray deterioration.

In addition, using a semiconductor fine processing technique,
_After etching a periodic groove with a period of several 100 nm on the surface of the substrate such as ₂ and depositing a metal such as Al with a thickness of several nm obliquely on the side surface of the groove, the Al attached to the plane other than the groove is ionized. By using milling, a polarizer (grating type polarizing element) having a large aspect ratio is manufactured. In this grating type polarizing element, it is difficult to increase the area because periodic grooves are formed by holographic exposure of a photoresist using interference fringes of light. In addition, since the process is complicated, the cost is high and it is not suitable for application to a display or the like. Further, in the short wavelength region of visible light which is close to the period of the groove, light is scattered and efficiency is reduced.

The anisotropic nanocomposite material according to the present example exhibits excellent polarization characteristics, and also has excellent durability because it uses an inorganic substance. In addition, when the polarizing plate is manufactured by the manufacturing method according to the present embodiment, a thin film type polarizing plate can be formed by one film formation compared to the case of the conventional size, which is low cost, simple, and has a large area. There is no problem. (Example 3)

This embodiment shows an example in which an anisotropic nanocomposite material is applied to a photovoltaic element that generates an electromotive force by light irradiation.

Using the same apparatus as in Example 1, a CdS target is mounted on the small sputter evaporation source 4 and a CdTe target is mounted on the other small sputter evaporation source 7, the substrate is kept at room temperature, and the input power of the CdS target is reduced. 220W, CdT
CdS and CdTe were simultaneously deposited on the substrate under the same conditions as in Example 1 except that the input power of the e target was set to 180 W.

The structure of the formed film was changed by SEM and TE.
When examined by M, it has an anisotropic nanocomposite structure,
FIG. 3 schematically shows the structure. This structure has an average thickness of 5 nm, an average length of 30 nm, and a height of about 500 nm, and is dispersed in a large number in a three-dimensional region from the substrate surface to the film surface. The material has a flat direction perpendicular to the incident direction. And was inclined at 5 degrees toward the evaporation source 4 with respect to the normal to the substrate surface. Part of the substance is closely connected to each other in a direction perpendicular to the incident surface of the deposition particles. This material consists of plate-like CdS and CdTe of almost the same thickness.
Has a shape in which they are stuck together.

The photovoltaic device using the anisotropic nanocomposite according to the present example was able to extract a very large short-circuit current.

Conventionally, a photovoltaic element has been disclosed in
129479 discloses that a transparent electrode, Cd
A photovoltaic cell has been proposed in which thin films of S, CdTe, and a counter electrode are laminated in the above order, and a photovoltaic power is generated by light irradiation from the glass side. This photovoltaic cell has an open circuit electromotive voltage of 750 m.
V, and a large number of laminated plates must be connected in series in order to obtain a voltage. Japanese Patent Publication No. 60-9179 proposes a photovoltaic device using an anisotropic nanocomposite material in which CdTe having a thickness of several hundred nm is obliquely deposited on a glass substrate.
Two gold electrodes extending in a direction perpendicular to a plane (incident surface) including the normal of the substrate and the incident direction of the deposited particles were vapor-deposited at an arbitrary interval on the surface of the CdTe film having the orientation by the oblique vapor deposition. With the basic configuration, a photovoltaic power of 100 V or more can be generated per 1 cm electrode spacing, but there is a drawback that a large current cannot be taken out.

The film manufactured according to the present embodiment is replaced with a conventional C
When the electrodes were arranged in the same configuration as the dTe photovoltaic element to form a photovoltaic element, and light was irradiated, the open circuit voltage was about 40 V per 1 cm between the electrodes, and the short circuit current was CdT of the same shape.
It was about 200 times that of the e-electromotive element. The mechanism is unknown, but like the CdTe electromotive element, CdS / CdTe
It is considered that the type photovoltaic cells were connected in series,
The reason why the short-circuit current can be increased is considered to be due to the photoconductivity of CdS. (Example 4)

In the fourth embodiment, an anisotropic nanocomposite material is converted into an optical phase plate, that is, [linearly polarized light → circularly polarized light (especially, a 波長 wavelength plate)] using the birefringence of a substance, or , [Linearly polarized light → linearly orthogonal to it (especially 1/2
An example in which the present invention is applied to a basic optical element that converts the polarization state of light will be described.

Using the same apparatus as in Example 1, a target of Ta ₂ O ₅ was mounted on both the small sputter evaporation sources 4 and 7, the substrate was kept at room temperature, the power supplied to both targets was 200 W, and the discharge time was A Ta ₂ O ₅ film was vapor-deposited on the substrate under the same conditions as in the example except that the time was changed to 30 minutes.

The structure of the formed film was determined by SEM and TEM.
As a result, it was found that it had an anisotropic nanocomposite structure, and the structure is schematically shown in FIG. That is, a substance having an average thickness of 5 nm, an average length of 30 nm, and a height corresponding to the film thickness of 1,500 nm is perpendicular to the substrate and has an average width of 3 n.
Many were dispersed through the voids of m. The anisotropic substance was oriented so that its flat direction was perpendicular to the direction of incidence of the deposited substance.

The anisotropic nanocomposite thin film according to the present example exhibited good birefringence, and even in a single layer, the birefringence was maximum in the direction normal to the substrate surface.

In the conventional inorganic birefringent thin film, after forming the first layer obliquely deposited on the substrate surface, inverting the substrate with respect to the evaporation source, and forming the second obliquely deposited layer, However, this embodiment can be easily manufactured by one film formation. (Example 5)

This embodiment shows an example of forming an anisotropic nanocomposite structure that can be expected to have a quantum size effect and optical anisotropy by using a device obtained by partially improving the device shown in FIG.

The anisotropic nanocomposite structure of the fifth embodiment is shown in FIG.
Was manufactured using the apparatus shown in FIG. In the apparatus shown in FIG. 7, the target is brought closer to the substrate as compared with the apparatus shown in FIG. However, this increases the spread of the incident angle of the deposition material incident on the substrate. Therefore, the substrate installation position is changed from the position A to the position B, and the expected angle of the target viewed from the substrate position is minimized.

A ZnTe target is mounted on the sputter deposition source 7, and a SiO ₂ target is mounted on the sputter deposition source 4. The Ar concentration in the depressurized container 8 was set to 5 × 10 ⁻³ mmHg, and discharge was started from both sputter evaporation sources. The power input to the ZnTe target was 10 W, the power input to the SiO ₂ target was 300 W, and Zn was placed on the substrate surface kept at room temperature.
Te and SiO ₂ were simultaneously deposited. The deposition amount was such that the weight ratio of ZnTe and SiO ₂ was 1: 1 and the incident angles were 55 degrees.

FIGS. 8, 9 and 10 show transmission electron microscope (TEM) images of the formed film at three observation magnifications. Observation is made from the normal direction of the film surface, the deposition direction is horizontal in each drawing, and ZnTe is
SiO ₂ is incident from the right side. FIG. 8 shows that the film surface is evenly filled with a characteristic fine structure, and in FIG. 9 which is further enlarged, relatively dark portions and relatively bright portions are alternately formed on the substrate surface. It is clearly shown that the area is filled up, and each of the regions has a different shape, but those shapes as a whole and most of the shapes when taken individually are both in the vertical direction. The extended average width is several nm and the average length is several tens nm, which indicates that the anisotropic nanocomposite structure according to the present invention has been realized.
In FIG. 10 which is further enlarged, a lattice image is observed in a relatively dark region having an average thickness of several nm and an average length of several tens nm extending in the vertical direction and its periphery, and the lattice spacing is Zn.
Since it corresponds to that of Te, it can be seen that this region is composed of ZnTe microcrystals on the order of nanometers.

On the other hand, no lattice image is observed at the center of a relatively bright region, and this is a typical image of an amorphous material.
It corresponds to ₂ . In such a structure, a quantum confinement effect occurs in the semiconductor fine particles ZnTe, and the development of a nonlinear optical effect is expected. FIG. 11 is actually measured data showing that a quantum confinement effect occurs in this sample, and the spectral transmission spectrum is shifted to a higher energy side by photon energy than bulk ZnTe deposited from the front (at a substrate temperature of 250 ° C.). . The vertical axis represents the transmittance T and the photon energy h.
The square of the product of ω, and the horizontal axis is hω. While the measured bulk value is the curve of the solid line, the ZnTe-S
The measured value of the iO ₂ anisotropic nanocomposite has shifted to the higher energy side. Furthermore, from the dashed curve measured by making the linear polarization of the probe light parallel to the flat direction of the anisotropic nanocomposite structure, the dashed line The curve shows a larger shift amount, indicating that the quantum confinement effect reflects anisotropy. FIG. 12 separately shows the spectral transmittance of the same sample when measured with the incident light linearly polarized in the vertical direction in FIG. 8 and the case where the spectral transmittance was measured with the incident light directly polarized in the horizontal direction in FIG. Things. Reflecting the structural anisotropy shown in FIG. 8, the former has a lower transmittance. As described above, the macro characteristics also indicate that the anisotropic nanocomposite structure according to the present example has been realized. (Example 6)

A co-evaporated film of W and Si was formed on the substrate surface in the same manner as in Example 5 using the apparatus shown in FIG. FIG. 13 shows a TEM image of the obtained film.

In this figure, W is deposited from below and Si is deposited from above. Although slightly different from FIG. 8, it also shows that the anisotropic nanocomposite structure according to the present invention has been realized. Similarly, a system of Pt and Si, or Cu and SiO ₂
And many other combinations of substances.

FIGS. 14 and 15 show the birefringence characteristics (FIG. 14) and the polarization characteristics (FIG. 15) of the anisotropic nanocomposite structure according to the present embodiment realized in the system of Cu and SiO ₂ . FIG. 14 is a graph in which the sample is rotated in-plane between two polarizing plates orthogonal to each other and the change in transmittance is plotted against the rotation angle. The absolute value of a straight line connecting each point and the origin indicates the transmitted light intensity, and the angle between the straight line and the x axis indicates the rotation angle.

If the sample does not have birefringence, transmitted light should disappear due to the effect of two orthogonal polarizing plates.
If the sample has birefringence, the incident light that has been linearly polarized by the first polarizing plate will have its principal axis direction of the optical anisotropy, which is the cause of the birefringence of the sample, shifted from the direction of the linearly polarized light. In the case of deviation, the linearly polarized light is converted into elliptically polarized light, so that the light is transmitted through the second polarizing plate. This effect is obtained when the deviation between the direction of the main axis of the optical anisotropy and the direction of the linearly polarized light is 4%.
The transmitted light intensity becomes maximum at 5 degrees, and the transmitted light intensity repeats maximum and minimum every 45 degrees of the rotation angle of the sample, and becomes a four-leaf clover type in polar coordinate display. FIG. 15 shows that the wavelength is 63.
In the transmittance measurement with 2.8 nm linearly polarized light, the sample is rotated in-plane and the change in transmittance is plotted against the rotation angle. The absolute value of a straight line connecting each point and the origin indicates the transmitted light intensity, and the angle between the straight line and the x axis indicates the rotation angle. These macro characteristics are not circular, but show a gourd shape, indicating that the nanocomposite material having anisotropy according to the present example has been realized.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing the structure of an anisotropic nanocomposite formed in Example 1 of the present invention.

FIG. 2 is a schematic diagram showing a structure of an anisotropic nanocomposite material formed in Example 2 of the present invention.

FIG. 3 is a schematic diagram showing a structure of an anisotropic nanocomposite formed in Example 3 of the present invention.

FIG. 4 is a view showing one specific example of an apparatus for producing the anisotropic nanocomposite material of the present invention.

FIG. 5 is a diagram showing a relationship between photon energy and transmitted light intensity.

FIG. 6 is a schematic diagram showing a structure of an anisotropic nanocomposite material formed in Example 4 of the present invention.

FIG. 7 is a view showing a specific example of an apparatus for producing the anisotropic nanocomposite material of the present invention.

FIG. 8 is a view showing a particle structure of an anisotropic nanocomposite material formed in Example 5 of the present invention.

FIG. 9 is a diagram showing a particle structure of an anisotropic nanocomposite formed in Example 5 of the present invention.

FIG. 10 is a view showing a particle structure of an anisotropic nanocomposite material formed in Example 5 of the present invention.

FIG. 11 is a diagram showing the relationship between the photon energy of the anisotropic nanocomposite material formed in Example 5 of the present invention and the square of the product of the transmittance and the photon energy.

FIG. 12 is a diagram showing the relationship between the energy of photons and the spectral transmittance of the anisotropic nanocomposite formed in Example 5 of the present invention.

FIG. 13 is a view showing a particle structure of an anisotropic nanocomposite material formed in Example 6 of the present invention.

FIG. 14 is a diagram showing the birefringence characteristics of the anisotropic nanocomposite formed in Example 6 of the present invention.

FIG. 15 is a diagram showing polarization characteristics of the anisotropic nanocomposite material formed in Example 6 of the present invention.

[Explanation of symbols]

1 ... substrate 2 ··· CdTe, Al, CdS, voids _{3 ··· SiO 2, CdTe, Ta} 2 O 5 4,7 ··· compact sputtering evaporation source 5 ... gauge 8 ... vacuum Vessel 9 ・ ・ ・ Vacuum pump 10 ・ ・ ・ Shutter 11 ・ ・ ・ Heating device 12 ・ ・ ・ Target

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor: Masaharu Noda 41-cho, Yokomichi, Nagakute-cho, Aichi-gun, Aichi, Japan 1 Toyota Central Research Laboratory Co., Ltd. (56) References JP-A-63-465 (JP, A) JP-A-63-255359 (JP, A) JP-A-64-17859 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 JICST file (JOIS)

Claims (13)

(57) [Claims] 1. A semiconductor device comprising a substrate and a film formed on the substrate.
The film is composed of at least one kind of nanoparticles, and the nanoparticles rise from the surface of the substrate and have a cross-sectional shape.
The average of the distance ( thickness ) of the minor axis part of is between 1 and 9 nm
In addition, the average of the distance ( length ) of the major axis is 10 to 90 nm in cross section and the nanoparticles are oriented in the direction of the major axis with respect to each other.
Dispersed with a gap in the direction of the major axis and the direction of the minor axis
Anisotropic nanocomposite material, characterized by that. 2. The method according to claim 1, wherein the nanoparticles overlap in the direction of the minor axis.
2. The anisotropic material according to claim 1, wherein the anisotropic material is formed of only two kinds of substances.
Nanocomposites. 3. The space between the nanoparticles is a space.
Item 3. An anisotropic nanocomposite according to item 1 or 2. 4. The method according to claim 1, wherein the gap between said nanoparticles is
The substance according to claim 1 or 2, wherein a substance other than the substance forming the substance is interposed.
Anisotropic nanocomposites. 5. The method according to claim 1, wherein the nanoparticles are inorganic oxidized substances,
1 and 3 are formed of an oxide, a semiconductor or a metal.
Or the anisotropic nanocomposite material according to 4. 6. The combination of the two substances is one substance
The substance is an oxidized or fluorinated substance and the other substance is a semiconductor or
Is a combination of metals, one substance is a semiconductor and the other is
A combination in which the substances are different semiconductors, or one substance is an acid
Is a fluoride or fluoride and the other substance is a metal
3. The anisotropic nanocomposite material according to claim 2, wherein 7. The material forming the nanoparticles and the gap
Combination of two kinds of substances that intervene in one is one substance
Are oxidized or fluorinated substances and other substances are semiconductors or
Combinations that are metals, one substance is a semiconductor, the other is
A combination of semiconductors of different qualities, or one substance is oxidized
A substance or fluoride and the other substance is a metal,
The anisotropic nanocomposite material according to claim 4, wherein 8. The oxidizing substance is MgO, Al _Two  O _Three  , S
iO, SiO _Two  , TiO _Two  , V _Two  O _Five  , CuO, Zn
O, GeO _Two  , ZnO _Two  , Nb _Two  O _Five  , MoO _Three  , In
_Two  O _Three  , SnO _Two  , HfO _Two  , Ta _Two  O _Five  , WO _Three  , B
i _Two  O _Three  , La _Two  O _Three  , CeO _Two  One or more of
And the fluorinated substance is CaF _Two  , CeF _Two  , MgF _Two
Wherein the semiconductor is CdS, CdS
Se, CdTe, GaAs, Ge, ZnTe, ZnS
One or more kinds, and the metal is Fe, Co, N
one or more of i, Au, Ag, Al, Pt, and Ca
The anisotropic nanocomposite material according to claim 5, 6 or 7, wherein 9. In a decompression container, the substrate normal to the surface normal
From a direction centered on a direction inclined by 30 to 89 degrees.
A substance whose center is in a direction different from the substance by 30 degrees or more
Simultaneously depositing the other substance on the substrate surface from the
A method for producing an anisotropic nanocomposite material. 10. The one substance and the other substance
The production of the anisotropic nanocomposite material according to claim 9, which is the same substance.
Construction method. 11. The substance is an inorganic oxidized substance, fluorinated substance.
105. The anisotropic material according to claim 104, wherein the material is a substance, a semiconductor, or a metal.
Manufacturing method of nanocomposite material. 12. A set of the one substance and the other substance
Combination is when one substance is an oxidized substance or a fluorinated substance and
One of the substances is a semiconductor or metal, and one is
Unions that are semiconductors and the other substance is a different semiconductor
Or one of the substances is an oxide or fluoride and the other is
10. The anisotropic composition of claim 9, wherein the substance is a metal.
For producing conductive nanocomposites. 13. The oxidizing substance is MgO, Al _Two  O _Three  ,
SiO, SiO _Two  , TiO _Two  , V _Two  O _Five  , CuO, Zn
O, GeO _Two  , ZnO _Two  , Nb _Two  O _Five  , MoO _Three  , In
_Two  O _Three  , SnO _Two  , HfO _Two  , Ta _Two  O _Five  , WO _Three  , B
i _Two  O _Three  , La _Two  O _Three  , CeO _Two  One or more of
And the fluorinated substance is CaF _Two  , CeF _Two  , MgF _Two
Wherein the semiconductor is CdS, CdS
Se, CdTe, GaAs, Ge, ZnTe, ZnS
One or more kinds, and the metal is Fe, Co, N
one or more of i, Au, Ag, Al, Pt, and Ca
The anisotropic nanocomposite according to claim 11 or 12,
Production method.