JPS6310560A - Rectifying device - Google Patents

Abstract

PURPOSE:To approach the size of a rectifier to the ultrafine size of a living body molecule level by forming first and second electron transmission protein films of electron transmission proteins having different redox potentials, and forming an organic thin film between the protein film and electrodes. CONSTITUTION:A metal thin film is formed by utilizing an ion beam method or a depositing method on a substrate 16 to form an electrode 17. An organic thin film 21 made of organic molecules or organic metal complex on the electrode 17. Then, cytochrome (c) and flavodoxin are used as the electron transmission protein to form a single molecule film and its accumulative films 18, 19. When the substrate 15 formed with the first protein 18 is inserted perpendicularly to a water tank having a flavodoxin film to be dipped, the flavodoxin film is bonded on the protein 18 to form a second electron transmission protein film 19. Then, an organic thin film 22 is formed by a depositing method on the film 19 of the substrate 16, a metal thin film is formed thereon at a low temperature, thereby obtaining electrodes 20.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a rectifying element in the field of integrated circuits, and by using biomaterials as the constituent material of the element, the size of the rectifier can be reduced to ultra-fine size at the level of biomolecules. It is designed to be able to accommodate large numbers of people (from several tens to hundreds of people), and to achieve high density and high speed.

[Conventional technology]

Conventionally, rectifying elements used in integrated circuits have had an MO3 structure as shown in FIG.

In the figure, 1 is a p-type silicon substrate, 2 is an n-shade region, and 3 is a p-type silicon substrate.
is a p-shaded region, 4 is an n-shaded region, 5 is a 5i02 film, and 6.7 is a 1st electrode, and a p-n junction (
A p-shaded region 3 - n-shaded region 4 junction) is formed, thereby realizing rectification characteristics.

[Problem that the invention seeks to solve]

Because the conventional MO3 structure rectifier is configured as described above, it can be microfabricated, and currently LSIs using rectifiers with the above structure or transistor elements with a similar structure are being used in 256-bit LSIs. has been put into practical use.

By the way, in order to increase the memory capacity and operation speed of integrated circuits, it is essential to miniaturize the elements themselves. On the other hand, in elements using St, ultra-fine patterns of about 0.2 μm are used to improve the mean free path of electrons and the elements. There is a limit in that the sizes are almost the same, and the independence of the elements cannot be maintained. In this way, silicon technology, which continues to develop day by day, is expected to eventually hit a wall in terms of miniaturization, and it is expected that electrical circuit elements based on new principles will break through the 0.2 μm wall. There is a need for people who can do this.

This invention was made in view of the above situation, and it is possible to create an electric circuit element whose size can be brought close to the ultra-fine size of the biomolecule level by using biomaterials as the constituent material of the electric circuit element. In particular, the purpose is to provide rectifying elements among them.

[Means for solving problems]

By the way, in the biological membranes of microorganisms and the inner membranes of mitochondria of higher organisms, H2, conjugated acids, NAD(P)H (formerly cotineamide) are present, although their functions are different.
enine DinucleoLide (Phosp
Along with enzyme proteins that extract electrons from reducing chemicals such as Existing.

These electron transfer proteins are embedded in biological membranes with a certain orientation and have a specific intermolecular arrangement so that electron transfer occurs between molecules.

As described above, since electron transport proteins are arranged in a chain in a sophisticated arrangement in biological membranes, it is thought that by utilizing this, it is possible to control the movement of electrons at the molecular level.

Figure 6 shows a schematic diagram of the electron transport chain in the mitochondrial inner membrane as an example of the chain of electron transport proteins (electron transport chain).
is an electron transport protein, and NADH is a reducing organic substance.
(L in the figure) and succinic acid (M in the figure) respectively.
The electrons extracted by -Q reductase 9 and succinate dehydrogenase 10 are transferred to NADH-Q reductase 9. Succinate dehydrogenase 10-cytochrome b (11)-cytochrome CIC12)-cytochrome c (13) → cytochrome a (14)-cytochrome a3 (15), and is finally transferred to oxygen at the exit side N. and produces water.

The electron transfer proteins shown in FIG. 6 involve an oxidation-reduction (redox) reaction during electron transfer, and electrons can flow from the negative unit of the redox potential of each electron transfer protein to the positive level. That is, it exhibits rectifying characteristics.

Furthermore, according to recent findings, electron transfer protein complexes capable of electron transfer are formed not only by electron transfer proteins present in the same organism but also by combining electron transfer proteins present in different organisms. It has been shown that it is possible to

Therefore, if we use 2fi class electron transfer proteins (A and B) with appropriate redox potentials and accumulate them in two layers, A-B, we can form a junction that produces rectifying properties by utilizing the difference in redox potential between them. The inventor of the present invention created this invention by paying attention to this fact.

That is, the rectifying element according to the present invention includes a first electron transfer protein film made of a first electron transfer protein, and a second electron transfer protein film having a redox potential different from the redox potential of the first electron transfer protein. a second electron transfer protein membrane made of a protein and cumulatively adhesively bonded to the first electron transfer protein membrane; The first is connected to the second electron transport protein. A second electrode and an organic thin film provided between each electrode and the corresponding electron transfer protein film are provided.

[Effect]

In this invention, a complex formed by joining at least two types of electron transport proteins with different redox potentials exhibits rectifying properties. Figure 5(a).

To explain using the schematic diagram of the A-B type electron transfer protein complex shown in t) and the relationship between its redox potentials, two electron transfer proteins A and B have different redox potentials.
In the composite formed by bonding the It exhibits a rectifying characteristic of being difficult to flow, and by using this composite, it is possible to obtain a rectifying element that exhibits properties similar to a pn junction formed by joining an n-type semiconductor and a p-type semiconductor.

In addition, in the present invention, since a thin film made of organic molecules or organometallic complexes is provided between the electrode and the electron transfer protein film, the orientation of the electron transfer protein is adjusted, and the relationship between the electrode and the electron transfer protein film is adjusted. The current can be transferred well between the two.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional configuration diagram of a device incorporating a rectifying element according to an embodiment of the present invention.
17 is a substrate with insulating properties and Ag.

A plurality of metal electrodes made of Au, A1, etc. are formed in parallel on the substrate 16. 21 is an organic thin film made of organic molecules or organometallic complexes accumulated on the metal electrode 17;
Reference numeral 18 denotes a first electron transfer protein film made of cytochrome C, which is an electron transfer protein, and is formed on the organic cylinders 15 and 21. Reference numeral 19 denotes a second electron transfer protein membrane made of flavotoxin, which is an electron transfer protein, and is cumulatively adhesively bonded to the first electron transfer protein membrane 18. 22
has the same structure as the organic thin film 21, and is an organic thin film formed on the second electron transfer protein 15!19, and 20 is a plurality of parallel electrodes formed in a direction perpendicular to the plurality of parallel electrodes 17. , is formed on the second electron transfer protein film 19 via the organic cylinder 19i22. Note that although the organic thin film 22 is formed only under the electrode 2o,
It may be provided on the entire surface of the second electron transport protein film 19 depending on the manufacturing method of the second electron transport protein film 19.

FIG. 2 is an exploded perspective view showing a device incorporating the formed rectifying element.

Next, a method for manufacturing the above device will be explained.

First, the ion beam method and the single molecular beam method are performed on the substrate 16.

A metal thin film is created using a vapor deposition method or the like, and the electrode 17 is formed. Then, an organic column IJ21 made of organic molecules or an organic gold H complex is formed on the electrode 17 by a vapor deposition method or the like. Next, using cytochrome C as the electron transfer protein and flavotoxin, a monolayer and a composite IIi film 18 of them were prepared.
．． 19, but to create these lines 18 and 19, L B (Langa+uir-Blo
dgett) method may be used. For details of this LB method, see ■ Journal of the Institute of Electrical Engineers of Japan, Vol. 55, 204-213.
Page, April 1919 (IwingLange+uir
), ■Journal of the American Chemical Society (Blodgett: Journalo)
f American Chemical 5ocie
ty) Vol 5L P1007+X935, ■Michio Sugi et al., Solid State Physics, Vol 17. P144-7
52. 1982, ■Journal of Colloid and Interface Science (Journal
of Co11oid and Interface
5science) Vol 6B, P471-477
, 1979, etc. - To explain an example, a cytochrome C solution is dropped onto the water surface of an aquarium to form a monomolecular film of cytochrome C on the water surface. Then, electrode 17 and organic thin film 2 were placed in the water tank in which this cytochrome C film was formed.
When the substrate 16 on which No. 1 is formed is vertically inserted and immersed, the cytochrome C film is adhered to and bonded to the substrate 16 having the electrode 17 and the organic thin film 21, thereby forming the first electron transport protein film 18. At this time, the substrate 16 was inserted into the water tank and immersed in it, but the cytochrome C film may be formed on the substrate 16 by pulling it up vertically from below the water surface.

Next, a flavotoxin solution is dropped onto the water surface of the aquarium to form a monomolecular film of flavotoxin on the water surface. And the first above
The substrate 16 on which the electron transfer protein 18 has been prepared is vertically inserted into a water tank having a flavotoxin film and immersed in it.
A flavotoxin film is adhered and bonded onto the first electron transport protein 18, and a second electron transport protein film 19 is created. Subsequently, an organic thin film 22 similar to the above is formed on the second electron transfer protein film 19 of the substrate 16 by a vapor deposition method, etc., and a metal thin film is formed thereon by using an ion beam method, a molecular beam method, a vapor deposition method, etc. Obtain the electrode 20 by making it at a low temperature that does not destroy the electron transfer protein.

In addition, the above 1. The second electron transfer protein membrane 18゜19 is
It may be a monomolecular film or may be a film overlaid with another electron transport protein film.

At this time, the redox potential difference between both electron transfer proteins of the overlapping membranes is the first. Select one that is smaller than the redox potential difference between both second electron transfer proteins. The redox potentials of various electron transfer proteins are described in "Tsunehiro Takano; Protein Nucleic Acid Enzyme, 27.PL543.1982", and the redox potential difference between cytochrome C and flavotoxin is about 665 mV.

Furthermore, in the above example, when forming the organic thin films 21 and 22, a case was described in which the organic thin films 21 and 22 were formed by a vapor deposition method, etc., but in this case, either a lipid or a fatty acid as an organic molecule was added to the electron transfer protein solution dropped onto the water surface in advance. After mixing, the mixed solution may be dropped onto the water surface to form a film on the water surface, and this may be adhered and bonded to the substrate.

Other methods for creating organic thin models and electron transfer protein films include modifying the surface of a metal electrode with organic molecules to form an organic thin film on the metal electrode, and immersing the electrode in a protein solution to remove the protein molecules described above. A method of adsorption onto an electrode having an organic thin film is also considered. In this method, one or two electrodes in addition to the above-mentioned electrodes that adsorb proteins are immersed in a solution, and a positive or negative potential is applied between the electrodes that adsorb proteins and the protein solution. It is also possible to control the adsorption of to the electrode.

Next, the effects will be explained.

Figure 3+a) shows the voltage between electrode 17 and electrode 20 of this device.
This shows the IV characteristics, that is, the rectification characteristics, when the voltage is applied. The flow of electrons in response to voltage application in this device is shown in Figure 5 (31,
It has the same effect as described in (b), and exhibits rectifying properties due to the difference in redox potential between cytochrome C and flavotoxin. In addition, in the region where the applied voltage ■ exceeds the range shown in Figure 3 (a), as shown in Figure 3 (bl), when the negative voltage is increased, the current decreases, indicating negative resistance, while when the positive voltage is When increased, a current is generated due to the reversal of the redox potential, which is due to the characteristics of the electron transport mechanism of the electron transport protein.

The configuration of this embodiment and the behavior of current change in response to voltage application are considered to be similar to conventional semiconductor rectifier elements (p-n junction type), and the above configuration allows the rectifier to be ultra-fine at the molecular level. It can be realized as an element of a large size, and high density can be achieved using this element.

A built-in circuit capable of increasing speed can be obtained.

Further, in the above embodiment, since an organic thin film is formed between the electrode and the electron transfer protein film, the organic molecules of the thin film support the orientation of the protein molecules, and the orientation of the electron transfer protein is adjusted. To explain this in terms of a model using the schematic diagram in FIG.
The concave portions 13a of the flavotoxin fit together, and the concave portions 19a of the flavotoxin and the convex portions 22a of the organic molecule fit together, thereby aligning the cytochrome C and the flavotoxin. Furthermore, when an electrode and an electron transfer protein are directly bonded, it may be difficult to transfer electrons between them, or the protein may be denatured, but by providing the organic thin film, the above problems can be resolved. Be able to form highly reliable devices.

Examples of electron transport proteins include non-heme iron/sulfur proteins, cytochrome C proteins, cytochrome b proteins, cytochrome a, flavotoxins, plastocyanins, and thioredoxins.
In selecting the second electron transfer protein, one is selected that allows electron transfer to occur in the orientation between molecules and the orientation with respect to the substrate on which the electrode is formed.

Furthermore, an enzyme may be used to supply electrons to the electron transfer protein.

In addition, each electron transfer protein is different! Taking advantage of the property that electrons flow only in a fixed direction between child transfer proteins, electrons flow in a direction perpendicular to the cumulative membrane, and electrons are exchanged between adjacent electron transfer protein molecules in a direction parallel to the cumulative MFJ. It is desirable to orient the molecules by the LB method or the like so as to take a predetermined molecular arrangement that will not occur. In addition, in the present invention, in order to improve the transfer of electrons between the metal electrode and the electron transfer protein membrane, an organic thin film was provided between the metal electrode and the electron transfer protein membrane.
A similar effect can be expected by chemical modification with 2,2''-bipyridyl, etc.

Further, in the above embodiment, the case where two layers of electron transport protein membranes are accumulated is explained, but three or more layers may be accumulated, and the same effect as in the above embodiment can be obtained.

〔Effect of the invention〕

As described above, according to the present invention, the first. By forming a second electron transport protein film and performing rectification, the size of the rectifying element can be brought close to the ultra-fine size at the level of biomolecules, and integrated circuits using this element can be fabricated. High density and high speed can be achieved. In addition, since a thin film was provided between the electron transfer protein film and the electrode,
This makes it possible to improve the orientation of the electron transfer protein, to improve the exchange of electrons between the protein and the electrode, and to prevent protein denaturation.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional configuration diagram of a device incorporating a rectifying element according to an embodiment of the present invention, FIG. 2 is an exploded perspective view of the device, and FIGS. I-
V characteristic diagram, Figure 4 is a schematic diagram for explaining the effect of the organic thin film formed in the rectifying element, Figure 5 (a) is a schematic diagram of the electron transfer protein complex, Figure 5 (b) ) is a diagram showing the redox potential, FIG. 6 is a schematic diagram showing the electron transport system of the inner membrane of mitochondria, and FIG. 7 is a cross-sectional view showing a conventional MO3 configuration rectifying element. 17.20... Electrode, 18... First electron transfer protein membrane, 19... Second electron transfer protein membrane, 21.22...
・Organic thin film. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (7)

[Claims] (1) A first electron transfer protein membrane made of a first electron transfer protein that can transfer electrons in a certain direction, and a second electron transfer protein membrane that has a redox potential different from that of the first electron transfer protein. a second electron transfer protein membrane cumulatively adhesively bonded to the first electron transfer protein membrane; first and second electrodes connected to the first and second electron transfer protein membranes, respectively; Provided between the first electron transfer protein membrane and the first electrode, and between the second electron transfer protein and the second electrode, which supports the electron transfer protein in an oriented manner and connects both the electron transfer protein membranes and the electrodes. and an organic thin film made of an organic molecule or an organometallic complex that facilitates the transfer and reception of current between the electron transfer protein and the electrolyte, and exhibits rectifying properties by utilizing the difference in redox potential between the first and second electron transfer proteins. A rectifying element characterized by: (2) The above electron transport proteins include non-heme-iron/sulfur proteins, cytochrome c-based proteins, cytochrome b-based proteins,
cytochrome a, flavodoxin, plastocyanin,
or thioredoxin, the rectifying element according to claim 1. (3) The rectifying element according to claim 1 or 2, wherein the electron transport protein film is a monolayer. (4) The rectifying device according to any one of claims 1 to 3, characterized in that an enzyme is used to supply electrons to the electron transfer protein. (5) The rectifying element according to any one of claims 1 to 4, wherein each of the electrodes is a metal electrode. (6) Each of the electron transfer protein membranes has electron transfer proteins that allow electrons to flow in a direction perpendicular to the direction in which each membrane is accumulated.
6. The rectifier element according to claim 1, wherein the rectifier element is oriented so that no electron transfer occurs between horizontally adjacent electron transfer protein molecules. (7) The rectifying element according to any one of claims 1 to 6, wherein the organic molecules constituting the organic thin film are either lipids or fatty acids.