JPH05183175A - Optical switching element - Google Patents

Abstract

PURPOSE:To accelerate an operating speed of an optical switching element to be used in an electronic industrial field by reducing an optical switching phenomenon in a charge transfer complex to a low order. CONSTITUTION:A substituent of a long chain is modified at one or both of an electron donor and an electron acceptor to form a structure of a crystal or a thin film to be formed thereby in an alternately laminated layer structure of a conductive layer and an insulating layer. In this case, a Coulomb interaction between carrier of the conductive layer and carrier of the adjacent conductive layer is very weakened. Then, an optical switching phenomenon of a charge transfer complex is generated by self-breeding step of the carrier, but since a decrease in the coulomb interaction between the carriers alleviates bounding of the carrier, its operating speed is accelerated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical switching device used in the electronic industry field.

[0002]

2. Description of the Related Art In recent years, the processing accuracy of semiconductor devices centered on silicon has reached the so-called submicron region, and the degree of integration has dramatically improved. However, since these functions utilize the function of the bulk of the inorganic semiconductor, the integration degree naturally has a physical limit.

On the other hand, since the organic molecule itself constitutes one closed system, one molecule serves as a basic unit of function. Therefore, when utilizing such a function, the size of the molecular order becomes the physical limit of processing accuracy, and due to the variety of functions possessed by organic molecules, higher integration and higher functionality than conventional inorganic semiconductor devices can be achieved. It is possible. Recently, the Langmuir-Blodgett method (hereinafter, L
The development of ultra-thin film forming techniques for organic molecules, represented by the B method) and vapor deposition methods, has led to active studies of devices using organic thin films.

Regarding an optical switching element using an organic substance, an organic thin film having a photoelectric conversion function is used so that an electrical switching function with respect to a light input, that is, an optical switching function is exhibited by utilizing a junction with a metal, a semiconductor or the like. Is becoming

[0005]

When using joining,
The surface state of the material forming the element greatly affects the characteristics of the element, and its electrical characteristics change under the influence of, for example, surface roughness. Therefore, the manufacturing process becomes complicated and process control is important.

In some organic materials, an optical switching phenomenon has been found as a property peculiar to the material in the charge transfer complex, but the operation speed is slow and it is on the order of several hundred msec, which is far from practical use. Is becoming

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide an optical switching element which has not been available in the past.

[0008]

In order to achieve the above object, the technical solution of the present invention provides an optical switching element which operates at high speed by reducing the optical switching phenomenon in a charge transfer complex. When a long-chain substituent is attached to the electron donor and / or the electron acceptor,
The structure of the charge transfer complex formed as shown in FIG. 1 is an alternating laminated structure of conductive layers and insulating layers formed by long-chain substituents, and the dimension of the electronic system can be reduced.

[0009]

According to the present invention, the operation speed of the photoswitching phenomenon of the conventionally known charge transfer complex can be increased. By modifying one or both of the electron donor and the electron acceptor with a long-chain substituent, the structure of the crystal or thin film composed of this becomes an alternating laminated structure of conductive layers and insulating layers. In this case, the Coulomb interaction between the carrier of the conductive layer and the carrier of the adjacent conductive layer is very weak due to the presence of the insulating layer. It is known that the photoswitching phenomenon in the charge-transfer complex is due to the self-propagation process of carriers, but such a decrease in Coulomb interaction between carriers relaxes the constraint of the carriers, resulting in faster operation speed. ..

[0010]

(Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings.

3,3 ', 5,5'-Tetramethylbenzidine (TMB) as an electron donor and 2-dodecyl-7,7,8,8-tetracyano having a long-chain alkyl group as an electron acceptor Charge transfer complex TMB-C12TCNQ was prepared by the co-sublimation method in a vacuum sealed tube using quinodimethane (C12TCNQ).

As a result of the structural analysis, as shown in the schematic view of FIG. 1, it is clear that the sheet has a structure in which the conductive layers made of TMB and TCNQ and the insulating layers made of docosyl group are alternately laminated. became.

When a pair of electrodes was formed on this crystal sample using silver paste and the change in current between both electrodes due to light irradiation was measured, the result was as shown in FIG.

That is, when the pulsed light (c) was input and the current response (a) was measured while a voltage lower than the voltage at which switching by voltage input occurs was applied to the element, the light input (c) caused an element Switched to a low resistance state and maintained its conducting state even after the light input (c) was cut off. When returning to the initial high resistance state, as shown in (b), the applied voltage can be lowered once, and then returning to the original voltage and applying the optical input (c) again, the same switching as above is repeated. It was The tracking speed of optical switching at this time was 1 kHz, which was 10 to 10,000 times faster than the conventional one.

(Example 2) N, N, N ', N'-as electron donors
Thin films were prepared from tetramethyl-P-phenylenediamine (TMPD) using 2-octadecyl-7,7,8,8-tetracyanoquinodimethane (C18TCNQ) as an electron acceptor. To make a thin film, first make a thin film of C18TCNQ by the LB method,
TMPD doping was performed there in a vacuum.

As shown in FIG. 3, a thin film 4 is formed so as to straddle both electrodes 2 and 3 by using vapor-deposited opposing gold comb-shaped electrodes 2 and 3 on a quartz substrate 1.
When the current change due to light irradiation was measured, the tracking speed of optical switching was 0.1 kHz, which was about the same as or higher than the conventional single crystal sample.

(Example 3) Crystals were prepared in the same manner as in Example 1 using TMB as an electron donor and 2-pentadecyl-7,7,8,8-tetracyanoquinodimethane (C15TCNQ) as an electron acceptor. A sample was prepared and further vapor-deposited by the vapor deposition method. As the substrate, the same quartz substrate on which the gold comb-shaped electrode as in Example 2 was deposited was used.

When the change in current due to light irradiation of this thin film element was measured, the following speed of optical switching was 0.1 kHz, which was about the same as or higher than that of the conventional single crystal sample.

(Other Embodiments) In the above embodiments,
Although a long-chain substituent is used for the electron acceptor, a substituent may be added to the electron donor.

Although an aromatic amine was used as the electron donor, other aromatic amine derivatives, tetrathiofulvalene and its derivatives, organic dyes, etc. may be used, and the electron acceptor may be tetracyanoquinodimethane or It may be a derivative thereof, a quinone-based molecule, an inorganic oxide or the like, but a combination of an electron donor and an electron acceptor is preferably a tetrathiofulvalene derivative and chloranil, a tetrathiofulvalene derivative and bromanil, TMB and tetracyanoquinodide. Methane derivative, TMPD and tetracyanoquinodimethane derivative,
Dimethylphenazine and tetracyanoquinodimethane derivatives are good, and further tetracyanoquinodimethane derivatives and tetrathiofulvalene derivatives are respectively

[Chemical 1]

[Chemical 2] (R ₁ is a substituent containing a hydrocarbon chain and R ₂ is a substituent containing hydrogen or a hydrocarbon chain).

[0021]

As is clear from the description based on the above examples, according to the present invention, the photoswitching phenomenon in the charge transfer complex can be made faster.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the structure of a charge transfer complex according to the present invention,

FIG. 2 is a waveform diagram of a current response due to light irradiation for explaining the operation of the optical switching element in the first embodiment.

FIG. 3 is a plan view showing a specific example of the optical switching element of the present invention.

[Explanation of symbols]

 1 Quartz substrate 2, 3 Comb electrode 4 Switching thin film

Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI technology display location // H01L 31/04 7376-4M H01L 31/04 D (72) Inventor Taro Minami Tama-ku, Kawasaki-shi, Kanagawa 3-10-1 Mita Matsushita Giken Co., Ltd. (72) Inventor Mutsumi Murakami 3-10-1 Higashimita Tama-ku, Kawasaki-shi, Kanagawa Matsushita Giken Co., Ltd.

Claims (4)

[Claims] 1. A charge transfer complex laminate comprising a laminate column having long-chain substituents in an electron acceptor and / or an electron donor and having electron acceptors and electron donors alternately arranged. An optical switching element characterized by the above. 2. The optical switching element according to claim 1, wherein the charge transfer complex used for the optical switching element is a single crystal. 3. The optical switching element according to claim 1, wherein the optical switching element is composed of a thin film, and the thin film is manufactured by the Langmuir-Blodgett method. 4. The optical switching element according to claim 1, wherein the optical switching element is composed of a thin film, and the thin film is manufactured by a vapor deposition method.