JP2806963B2 - Optical switch element - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical switching device in the field of integrated circuits. More specifically, by using an oxidation-reduction substance as a constituent material of the element, the size can be brought close to an ultra-fine size (tens to hundreds of square meters) at the molecular level, and high density and high speed can be achieved. The present invention relates to an optical switch element which can be used.

[Related Art] Conventionally, as a switching element used in an integrated circuit, there is a field effect transistor (FET) shown in FIG. In the figure, (12) is an n-type silicon substrate, (13) is a channel region, (14) is a P ⁺ layer, (15) is a SiO ₂ film, (16) is a source electrode, (17) is a gate electrode, Reference numeral 18) denotes a drain electrode. The conventional FET is operated as a transistor or a switching operation by controlling a gate voltage applied through a gate electrode (17). That is, the source electrode (16) and the drain electrode (18) depend on the gate voltage.
The number of current carriers in the surface layer therebetween is changed to control the current.

[Problems to be Solved by the Invention] Since the conventional switch element is configured as described above, fine processing is possible, and at present, an LSI using the switch element having the above structure or a rectifying element having a similar structure is used. A 256Kbit LSI has been put to practical use.

By the way, in order to increase the memory capacity and operation speed of an integrated circuit, miniaturization of the element itself is indispensable.
In an element using the device, the mean free path of electrons and the element size are almost equal in an ultrafine pattern of about 0.2 μm, and there is a limit that the independence of the element cannot be maintained. In this way, silicon technology, which is continuing to evolve every day, is expected to eventually hit the wall in terms of miniaturization, and is an electric circuit element based on a new principle, and the above-mentioned 0.
There is a need for one that can break a 2 μm wall.

The present invention has been made in view of such circumstances, and by using an oxidation-reduction substance as a constituent material of an electric circuit element, an electric circuit element whose size can be brought close to an ultra-fine size on a molecular level, in particular, The purpose is to obtain an optical switch element.

[Means for Solving the Problems] By the way, in a living body, there are a plurality of types of proteins having an electron transfer ability for carrying electrons in a predetermined direction (hereinafter, referred to as electron transfer proteins). Is embedded, for example, in a biological membrane with a certain orientation, and has a specific intermolecular arrangement so that electron transfer occurs between the molecules.

This electron transfer protein involves an oxidation-reduction (redox) reaction during electron transfer, and can flow electrons from a negative level to a positive order in the redox potential of each electron transfer protein. It is thought that the movement of electrons can be controlled at the molecular level.

Also, recent findings indicate that it is possible to form an electron transfer complex capable of transferring electrons by combining electron transfer substances other than the electron transfer protein present in the living body. .

Therefore, if two types (A and B) of electron transfer materials having appropriate redox potentials are used and two layers are bonded and bonded to AB or three layers are bonded to ABA, the difference in redox potential between them is obtained. It can be considered that a junction which causes a transistor characteristic or a switching characteristic can be formed by utilizing the above. The present inventors have focused on this fact and created the present invention.

That is, the present invention provides a first redox substance film made of a first redox substance, and a second redox substance having a redox potential different from that of the first redox substance, which is bonded and bonded to the first redox substance film. A second redox material film, a first electrode electrically connected to the first redox material film, and a second electrode electrically connected to the second redox material film. An optical switching device, wherein the first redox substance has a general formula (I): (Wherein, R ¹ and R ² represent a hydrogen atom or an alkyl group consisting of the following combinations: (i) R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms R ² is an alkyl group having 15 to 20 carbon atoms Group (ii) R ¹ is an alkyl group having 6 to 20 carbon atoms R ² is an alkyl group having 6 to 20 carbon atoms (iii) R ¹ is an alkyl group having 15 to 20 carbon atoms R ² is a hydrogen atom or a carbon atom having 1 to 20 carbon atoms. 5 represents an alkyl group R ³ and R ⁴ each represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a substituent containing a carbonyl group, a methylthioacetic acid group or a methylthiosuccinic acid group) and a general formula ( II): General formula (III): General formula (IV): (Wherein M represents Fe or Ru, X, Y and Z are ligands for M, and depending on the type and valence of M, (II)
(III) or structure (IV) can take, each halogen atom, CO, -OCOCH _3, pyridine, imidazole, (lower alkyl group for R is _{C 1 ~C 4) P (OR} ) 3 or PR ₃ X and Y may be the same or different, m and n each represent an integer of 5 to 20, m and n
May be the same or different), using either one of the porphyrin metal complex or an alkali metal salt thereof (porphyrin derivative), and using one of the waste as the second redox substance, An optical switch element (hereinafter also referred to as an AB type switch element) configured to generate a transistor characteristic or a switching characteristic by utilizing a difference in redox potential of a substance; and a first redox substance comprising a first redox substance A film, a second redox substance having a redox potential different from the first redox substance, and a second redox substance film bonded and bonded to the first redox substance film; and a redox potential having a second redox substance. A third oxidation-reduction substance film made of a third oxidation-reduction substance different from A first electrode electrically connected to the reducing substance film, a third electrode electrically connected to the third redox substance film, and a second electrode for electrically affecting the second redox substance film. Wherein the first redox substance is a flavin derivative represented by the general formula (I), and the second redox substance is a general formula (II) or (III) A porphyrin metal complex represented by the general formula (IV) or an alkali metal salt thereof (porphyrin derivative):
Using the flavin derivative as a third redox substance, or using the porphyrin derivative as a first redox substance, the flavin derivative as a second redox substance, and the porphyrin derivative as a third redox substance Thus, an optical switch element (hereinafter, referred to as A) that generates a transistor characteristic or a switching characteristic by utilizing a difference in redox potential of the redox substance.
-BA type switch element).

[Operation] In the present invention, transistor characteristics or switching characteristics are generated by at least two types of redox substances having different redox potentials.

In other words, using a schematic diagram of the AB-type redox substance complex shown in FIGS. 2a and 2b and a diagram showing the relationship between redox potentials, two redox substances A and B having different redox potentials are joined together. In the composite, the electrons easily flow from the negative level of the redox potential to the positive level as shown by the solid arrow in the figure, but hardly flow in the opposite direction (the direction of the broken arrow in the figure). . This complex can change the redox potential of A or B by irradiating light, so that the redox electron difference between A and B changes before and after irradiating light. This change is associated with a change in the moving speed of the electrons from A to B (or from B to A), and the electrical property is a change in the electric conductivity, so that the switching characteristics can be obtained.

3A to 3C, a schematic diagram of the ABA-type redox substance complex and a diagram showing the relationship between the redox potentials thereof will be described. In the composite, the redox potential of A, B, and A redox substances is controlled by controlling the voltage applied to the redox substances A or B, or by using a change in the material structure due to light, a magnetic field, or a mechanical force. Can be changed, whereby a transistor characteristic or a switching characteristic similar to a pnp junction formed by joining an n-type semiconductor and a p-type semiconductor is developed.

[Examples] As a redox substance used in the present invention, a flavin derivative and a porphyrin derivative are used because redox reaction occurs stably because the substance is a biological membrane mimetic, and the electron transfer rate is high.

As the flavin derivative, general formula (I): The compound shown by these is mentioned.

R ¹ and R ² in the general formula (I) are a hydrogen atom or an alkyl group having the following combination.

(I) R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms R ² is an alkyl group having 15 to 20 carbon atoms (ii) R ¹ is an alkyl group having 6 to 20 carbon atoms R ² is 6 to 20 carbon atoms (Iii) R ¹ is an alkyl group having 15 to 20 carbon atoms R ² is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms Since R ¹ and R ² are a combination of the groups described above, the polarity is controlled. This makes it possible to produce a uniform monomolecular film on the water surface.

R ³ and R ⁴ each represent a hydrogen atom, a carbon number of 1 to 5;
A substituent containing an alkyl group, an arbonyl group, a methylthioacetic acid group or a methylthiosuccinic acid group. R ³ and R ⁴
Are these groups, so that the number of anions per molecule can be changed to 0, 1, and 2. Further, the position of the isoalloxazine ring in the monomolecular film can be controlled. Further, the orientation of the isoalloxazine ring in the monomolecular film can be controlled.

Preferred specific examples of the flavin derivative include, for example, And so on.

The porphyrin derivative has a general formula (II): General formula (III) Or the general formula (IV): (Porphyrin metal complex).

M in the general formulas (II) to (IV) is Fe or Ru;
Is Fe or Ru, so that a redox reaction between divalent and trivalent occurs stably.

X, Y and Z in the general formulas (II) to (IV) each represent a halogen atom, CO, —OCOCH ₃ , pyridine, imidazole, P (OR) ₃ or PR ₃ (R is lower alkyl of C _{1 to} C ₄ ) Group). When X, Y, or Z is not one of these atoms and groups, the stability of the divalent or trivalent state is low, and deterioration is likely to occur. Note that X and Y may be the same or different.

M and n in the general formulas (II) to (IV) are 5 to 5, respectively.
20, preferably an integer of 5 to 15. When m or n is less than 5, the compounds represented by the general formulas (II) to (IV) become insufficient in hydrophobicity and cannot form a monomolecular film suitable for forming an LB film. , More than 20, the hydrophobic alkyl chains of the compounds represented by the general formulas (II) to (IV) become too long, and the distance between porphyrin rings between layers becomes too long when a monomolecular film is formed. In addition, the electron transfer characteristics are reduced. Note that m and n may be the same or different.

The alkali metal salt of the porphyrin metal complex is an alkali metal salt of the compound represented by any one of the general formulas (II) to (IV). Examples of the alkali metal include Na and K. In the alkali metal salt of the porphyrin metal complex used in the present invention, one of the carboxyl groups in the general formulas (II) to (IV) may be a salt, or two may be salts.

Preferred specific examples of the porphyrin derivative include:
For example (Py indicates pyridine) And so on.

Next, among the switch elements of the present invention, an AB type optical switch element having two redox substance films will be described.

In this optical switch element, one of the flavin derivative and the porphyrin derivative is used as the first redox substance, and one of the waste as the second redox substance is used. At this time, the difference in the redox potential between the first redox substance and the second redox substance is 0.3 to 0.3 to increase the electron transfer speed and increase the photoelectric conversion efficiency.
It is preferably 1.0V.

Each of the first redox substance film and the second redox substance film made of the redox substance has a thickness of 10 to 500.
{Circle around (1)}, especially 10-100 °, is preferable in terms of shortening the electron transit time and increasing the response speed as an element.

Examples of such a film include a Langmuir-Blodgett (LB) method, an MBE (Molecular Beam Epitaxy) method, and a vacuum evaporation method (Chemica
l Vapor Deposition, CVD (Chemical Vapor Deposition)
por deposition) method, but from the viewpoint of accumulation of organic molecules in a form maintaining a stable ordered structure of monomolecular films, monomolecular films obtained by the LB method and about 2 to 10 layers Are preferred. In the LB method, as a result of the study of the present inventors, the orientation can be controlled by controlling the film thickness at the time of film formation, and a film thickness of 25 to 32.5 mN · m ^-1 (millinewton per meter) can be obtained. It was found that both the flavin LB film and the porphyrin LB film exhibited good orientation.

 FIG. 1 shows an example of the AB type switching element.

FIG. 1 is a cross-sectional view schematically showing the switch element, in which (1) is a substrate having insulating properties such as glass, (2a) and (2b) are first and second electrodes, respectively.
(3) and (4) are first and second redox substance films, respectively. In this example, the first redox substance film (3) is a monolayer film of porphyrin derivative molecules produced by the LB method, and (5) is a hydrophilic porphyrin ring (6).
Is a hydrophobic methylene chain. The second redox substance film (4) is a monomolecular accumulation film of flavin derivative molecules prepared by the LB method, (7) is a hydrophilic isoalloxazine ring, and (8) is a hydrophobic methylene chain. . The first redox substance film (3) and the second redox substance film (4) are bonded and bonded.

The electrodes are for applying a predetermined voltage between the oxidation-reduction substance films, and include ordinary metal electrodes made of Ag, Au, Al, etc., and transparent electrodes made of SnO ₂ , ITO, or the like. Note that the adhesive bonding referred to in this specification is to form a first redox material film by an LB method, an MBE method, a CVD method or the like, and then form a second redox material film on the upper layer by an LB method or the like. Easy to obtain. As light used for light irradiation, light having a wavelength at which the first or second redox substance film absorbs light is used. For example, in the case of flavin derivatives, 250-520
Light with a wavelength in the nm range is used. The method of light irradiation may be a general method, and is not particularly limited.

Next, among the optical switch elements of the present invention, (ABA type) switch elements having three layers of redox substance films will be described.

In this switch element, (a) the flavin derivative as a first redox substance,
Using the porphyrin derivative as the second redox substance, the flavin derivative as the third redox substance, or (b) the porphyrin derivative as the first redox substance, and the flavin derivative as the second redox substance The porphyrin derivative is used as a third redox substance.

At this time, the difference in redox potential between the first or third redox substance and the second redox substance is preferably 0.3 to 1.0 V from the viewpoint of increasing the electron transfer speed and increasing the photoelectric conversion efficiency.

The first, second, and third redox substance films made of the redox substance each have a thickness of 10 to 500 Å, particularly 1 to 500 Å.
The angle of 100 to 100 ° is preferable from the viewpoint of shortening the electron transit time and increasing the response speed as an element. Examples of such a film include films prepared by the LB method, MBE method, vacuum mounting method, CVD method, etc., similarly to the optical switch element having the two-layer redox material film, but the film was prepared by the LB method. It is preferably a monomolecular film or a cumulative film having about 2 to 10 layers.

FIG. 3b shows an example of the ABA type switch element which is controlled by an electric field.

In FIG. 3b, a first redox material film (10a) is adhesively bonded to one surface of a second redox material film (11), and a third redox material film (10c) is ) Are adhesively bonded. The electrodes (9a) and (9c) are electrically connected to the first and third redox substance films (10a) and (10c), respectively. (9b) is an electrode for electrically affecting the first redox substance film (11), that is, for changing the redox potential of (11) by an electric field.

The voltage application state of such an ABA type switch element and the redox potential state of each redox substance at this time will be described with reference to FIGS. 3b to 3c. In FIG. 3c, the redox potential in the state (a) indicated by the solid line indicates a state where the voltages (V ₁ ) and (V ₂ ) are not applied, and the redox potential in the state (b) indicated by the dashed line indicates the voltage (V ₁ ) without applying
In addition, the state (off state) when the potential (V ₂ ) is applied as a negative voltage to the electrode (2c) is shown. The redox potential in the state (c) shown by the broken line is the voltage (V ₂ ) as the state (b). A state (ON state) when a voltage (V ₁ ) is applied as a negative voltage to the electrode (2c) while the voltage is applied similarly is shown.
(E) is an electron transmission path.

In the state (b), no electrons flow between the electrode (9c) and the electrode (9a), and in the state (c), the electrons flow. That is, a constant negative voltage (V ₂ ) is applied between the electrodes (9c) and (9a), and a constant negative voltage (V ₁ ) between the electrodes (9c) and (9b) is turned on. -By turning off, the electrodes (9c) and (9
It is possible to turn on and off the current flowing between the circuit and a), thereby realizing switching characteristics. (V ₀ ) is the flavin derivative (10a), (10c) and the porphyrin derivative (11)
And the redox potential difference.

Next, an example of a method for manufacturing the optical switch element of the present invention will be described.

In the AB type switching element of the present invention, for example, first, an electrode is formed on a substrate by an ion beam method, a molecular beam method, an evaporation method, a CVD method, or the like. Next, a first redox material film is formed by the LB method or the like so as to be in contact with the electrode, and a second redox material film is formed thereon by the LB method or the like. Next, an AB switch element is formed by forming an electrode so as to be in contact with the upper redox substance film. Also, AB
The -A type switch element is manufactured, for example, by forming the first and second redox substance films in the same manner as the AB type switch element and forming the third redox substance film by the LB method or the like.

Hereinafter, an embodiment of the present invention will be described more specifically with reference to FIG.

Example 1 First, a plurality of electrodes (2a) made of Al were formed in parallel (1 mm intervals) with a thickness of 1000 mm and a width of 1 mm on a substrate (1).

Next, using this substrate, the formula: The Ru-porphyrin metal complex (RPPH) represented by the formula (1) was accumulated in 9 molecular layers at a film thickness of 27.5 mN · m ^-1 by the LB method to form a first redox substance film (3) (FIG. 1 shows a 3 molecular layer). Abbreviated).

Then, on a substrate consisting of (1), (2a) and (3), the formula: The second redox substance film (4) is formed by accumulating 10 molecular layers of 3,10- (dinonyl-7,8-dimethylisoalloxazine (DNI) represented by LB method at a film pressure of 30 mN · m-1 by the LB method. (In FIG. 1, the second redox substance film (4) is accumulated and bonded to the first redox substance film (3).

Next, a translucent second electrode (2b) made of a plurality of Al layers having a thickness of 100 mm and a width of 1 mm in parallel (1 mm intervals) was formed in a direction perpendicular to the electrode (2a).

A wavelength of 450 nm is applied to the switch element thus manufactured.
At about 400 μW. FIG. 4 shows the response of the output current. The redox potential of RPPH was about 700 mV than the redox potential of DNI, and the switch characteristics were obtained by light irradiation based on the difference in redox potential between the two. Here, the case where the base electrode (2a) is grounded and + 1V, 0V, -1V is applied to the upper semi-transparent electrode (2b) is shown. It was found that the photocurrent response was large at each applied voltage, and that a very large photoresponse was obtained especially at +1 V bias. This result indicates that the AB type two-layer cell of this configuration functions as an optical switch.

In the first embodiment, the case where a monolayer film of a porphyrin derivative and a monolayer film of a flavin derivative are respectively used as the first redox material film and the second redox material film has been described. The LB film may be a monomolecular film. One of the first redox material film and the second redox material film may be an LB film and the other may be a redox material film other than the LB film, and both may be redox material films other than the LB film. Is also good. Further, although the example of the first embodiment has an AB type two-layer structure, it may have an ABA type three-layer structure, and an electric field is applied instead of light irradiation as shown in FIG. By doing so, the redox potential may be controlled.

[Effects of the Invention] As described above, according to the present invention, an optical switch element that performs the same operation as a conventional semiconductor switch element (such as a pnp junction type) is used as an element having an ultrafine size on a molecular level. Thus, an integrated circuit which can be expressed and whose density and speed can be increased by using the element can be obtained. In addition, this device can easily accumulate redox material films regardless of the nature of the underlying substrate, which facilitates the configuration as a three-dimensional device, and can be used with conventional compound semiconductor devices such as Si semiconductors and GaAs. It can be easily configured as a hybrid device in combination.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically showing a configuration of an optical switch element according to an embodiment of the present invention, and FIGS. 2a to 2b are schematic views showing an AB type redox substance complex and a description of a redox potential state thereof. FIG. 3A is a schematic view showing an ABA-type redox substance complex, and FIGS. 3B to 3C are schematic views showing a voltage application state of an ABA-type switch element by electric field control and their respective figures. FIG. 4 is an explanatory diagram of a redox potential state of a redox substance, FIG. 4 is a graph showing a photocurrent response of the switch element of Example 1, and FIG. 5 is a cross-sectional view showing an example of a conventional switch element having a MOS configuration. .

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Mitsuo Maeda 8-1-1, Tsukaguchi-Honmachi, Amagasaki-shi, Hyogo Mitsubishi Electric Corporation Central Research Laboratory (56) References JP-A-63-237563 (JP, A)

Claims (2)

(57) [Claims] 1. A first redox substance film made of a first redox substance, and a second redox substance having a redox potential different from that of the first redox substance, and bonded to the first redox substance film. A second redox material film, a first electrode electrically connected to the first redox material film, and a second electrode electrically connected to the second redox material film. An optical switching device, wherein the first redox substance has a general formula (I): (Wherein, R ¹ and R ² represent a hydrogen atom or an alkyl group consisting of the following combinations: (i) R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms R ² is an alkyl group having 15 to 20 carbon atoms Group (ii) R ¹ is an alkyl group having 6 to 20 carbon atoms R ² is an alkyl group having 6 to 20 carbon atoms (iii) R ¹ is an alkyl group having 15 to 20 carbon atoms R ² is a hydrogen atom or a carbon atom having 1 to 20 carbon atoms. 5 represents an alkyl group R ³ and R ⁴ each represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a substituent containing a carbonyl group, a methylthioacetic acid group or a methylthiosuccinic acid group) and a general formula ( II): General formula (III): General formula (IV): (Wherein M represents Fe or Ru, X, Y and Z are ligands for M, and depending on the type and valence of M, (II)
(III) or structure (IV) can take, each halogen atom, CO, -OCOCH _3, pyridine, imidazole, (lower alkyl group for R is _{C 1 ~C 4) P (OR} ) 3 or PR ₃ X and Y may be the same or different, m and n each represent an integer of 5 to 20, m and n
May be the same or different), using either one of the porphyrin metal complex or an alkali metal salt thereof (porphyrin derivative), and using one of the waste as the second redox substance, An optical switching device that generates a transistor characteristic or a switching characteristic by utilizing a difference in a redox potential of a substance. 2. A first redox substance film made of a first redox substance, and a second redox substance having a redox potential different from the first redox substance, and bonded to the first redox substance film. A second redox substance film, a third redox substance film made of a third redox substance having a redox potential different from that of the second redox substance, and adhesively bonded to the second redox substance film; A first electrode electrically connected to the first redox material film, a third electrode electrically connected to the third redox material film, and a second electrode for electrically affecting the second redox material film. An optical switch element comprising a second electrode, wherein the first redox substance has a general formula (I): (Wherein, R ¹ and R ² represent a hydrogen atom or an alkyl group consisting of the following combinations: (i) R ¹ is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms R ² is an alkyl group having 15 to 20 carbon atoms Group (ii) R ¹ is an alkyl group having 6 to 20 carbon atoms R ² is an alkyl group having 6 to 20 carbon atoms (iii) R ¹ is an alkyl group having 15 to 20 carbon atoms R ² is a hydrogen atom or a carbon atom having 1 to 20 carbon atoms. 5 alkyl groups R ³ and R ⁴ each represent a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, a substituent containing a carbonyl group, a methylthioacetic acid group or a methylthiosuccinic acid group), General formula (II) as a redox substance: General formula (III): General formula (IV): (Wherein M represents Fe or Ru, X, Y and Z are ligands for M, and depending on the type and valence of M, (II)
(III) or structure (IV) can take, each halogen atom, CO, -OCOCH _3, pyridine, imidazole, (lower alkyl group for R is _{C 1 ~C 4) P (OR} ) 3 or PR ₃ X and Y may be the same or different, m and n each represent an integer of 5 to 20, m and n
May be the same or different), or an alkali metal salt thereof (porphyrin derivative), using the flavin derivative as the third redox substance, or using the porphyrin as the first redox substance By using the flavin derivative as the derivative and the second redox substance and the porphyrin derivative as the third redox substance, a transistor characteristic or a switching characteristic can be generated by utilizing a difference in redox potential of the redox substance. Optical switch element.