JP2000345321A - Optical semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical semiconductor device improved in sensitivity to a degree in which the efficiency of photoelectric current quanta exhibits the amplification of >1 by using a molecular photoconducting material and accompanied by reproducibility. SOLUTION: A space between two electrode layers composed of materials selected from the groups consisting of tin, indium, aluminum, copper, chromium, titanium, iron, nickel and platinum or thin oxide or indium tin oxide whose surfaces may have oxide layers is provided with a sensitive layer composed of an organic vapor deposition film obtd. by vapor-depositing a molecular photoconducting material at a vapor depositing rate of <=0.07 nm/sec.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical semiconductor device, and more particularly, to an optical semiconductor device having extremely high sensitivity useful for an optical sensor or the like.

[0002]

2. Description of the Related Art Conventionally, various inorganic and organic photoconductive materials have been used as a photoconductive material such as an optical sensor (see "Molecular Semiconductor").
Semiconductor) "(Springer-Buarlag (Spr
inger-Verlag), published 1985)). An optical semiconductor element using such a photoconductive substance is generally one in which a photoconductive substance is sandwiched between two electrodes to form an element, or one in which a comb-shaped electrode is formed on the photoconductive substance.

In these optical semiconductor devices, the expression Φ =
The photocurrent quantum efficiency (Φ) (ratio of the number of generated carriers (ep) to the number of absorbed photons (Np)) expressed by ep / Np does not exceed 1.

However, "Optoelectronic Semiconductor Devices (Optoelectronic S
emiconductor devices ”(Prentice Hall (Pren
ticeHall), published in 1994), among optical semiconductor devices such as Si, when a voltage of several tens of volts to several hundreds of volts is applied to a reverse bias of an avalanche device, the avalanche phenomenon of electrons occurs. It has been reported that this phenomenon causes photocurrent amplification and an apparent quantum efficiency exceeding 1. In addition, "Journal of Non-Cryst. Solids (J. Non-Cryst. Solids)" (No. 137
& 138, p. 1283, 1991)
(Indium tin oxide) / pa-SiC: H / a-
When a high voltage is applied to a Schottky barrier element having a structure of SiN / ia-Si / nμcSi: H / Al, amplification of quantum efficiency occurs, and when a voltage of 10 V or more is applied, the photocurrent quantum efficiency exceeds 1; It has been reported that the photocurrent quantum efficiency sometimes shows about 10.

[0005] On the other hand, similar amplification phenomena have been reported in devices using molecular photoconductive materials. “Applied Physics Letter (Appl. Phys. Lett.)” (No. 64
Vol. 187, 1994) and "Surface Science" (Vol. 15, p. 579, 1994) describe the non-uniformity of the interface between Au and perelin pigment deposited film with the structure of Au / perylene pigment deposited film / Au. For this reason, it is reported that the photocurrent quantum efficiency reaches 10,000 when a voltage of 15 V is applied.

[0006]

However, in an avalanche photodiode using an inorganic material, application of a voltage of several tens of volts to hundreds of volts is required to cause amplification of a photocurrent. There is no report that such an effect has occurred in a device using an organic semiconductor. In addition, ITO (indium tin oxide) / pa-SiC: H
In a Schottky barrier element having a configuration of / a-SiN / ia-Si / nμcSi: H / Al, quantum efficiency is amplified by applying a relatively low voltage as compared with an avalanche photodiode. However, the amplification phenomenon of the quantum efficiency in the Schottky barrier device is a two-stage process, that is, the first stage is microsecond, the second stage is millisecond-
It increases after a slow response of tens of seconds.

On the other hand, in the case of a molecular photoconductive material, 10,000
Although double amplification has been reported, the light response speed is slow, requiring several tens of seconds to several minutes. In this molecular semiconductor device,
It is said that the amplification effect occurs due to the interface between the electrode and the perylene pigment vapor-deposited film. However, the state of the interface is not clarified, and it is difficult to manufacture the film with good industrial reproducibility. Also,
For example, “Chemical Review (Chem. Rev.)” (Vol. 97, pp. 1793 to 1896, 1997), “Molecular Semiconductor” (Springer-Verlag, 1985), etc. Reported many devices having a structure of Au / perylene pigment vapor-deposited film / Au, but there was no report that the light quantum efficiency exceeded 1.

[0008] As described above, even though some of the devices using the molecular photoconductive material exhibit an amplification whose photon efficiency exceeds 1, the origin is not clear. It is still an unsatisfactory situation to construct an optical amplifier with good reproducibility. The problem to be solved by the present invention is to provide an optical semiconductor device with improved sensitivity and reproducibility until the photocurrent quantum efficiency shows an amplification exceeding 1 using a molecular photoconductive material. It is in.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that the deposition rate is reduced to 0.
It has been found that an optical semiconductor device having a photosensitive layer having a vapor deposited film obtained by vapor deposition at a wavelength of 07 nm / sec or less has an increased photocurrent, a high response speed, and improved sensitivity, and has completed the present invention. .

That is, the present invention provides (1) an optical semiconductor device having a photosensitive layer comprising an organic vapor-deposited film between two electrode layers, wherein the electrode layer has an oxide layer on the surface. An electrode layer made of a material selected from the group consisting of tin, indium, aluminum, copper, chromium, titanium, iron, nickel and platinum, or a tin oxide or indium tin oxide electrode layer, wherein the photosensitive layer is a molecular layer. Provided is an optical semiconductor device, which is a deposited film obtained by depositing a conductive photoconductive material at a deposition rate of 0.07 nm / sec or less.

In order to solve the above-mentioned problems, the present invention provides (2) an optical semiconductor device as described in (1) above, wherein the deposited film is obtained by vapor deposition at an electrode layer surface temperature of 100 ° C. or higher. I do.

Further, in order to solve the above-mentioned problems, the present invention provides (3) the above-mentioned (1) or (2), wherein the molecular photoconductive material is a material selected from the group consisting of phthalocyanines and fullerenes. An optical semiconductor device is provided.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One optical semiconductor device having a photosensitive layer made of a molecular photoconductive material according to the present invention has a structure as shown in the plan view of FIG. 1 and the sectional view of FIG. A photoconductive substance made of a material is sandwiched between two electrodes to constitute one element, or a photoconductive substance made of a molecular photoconductive material as shown in the plan view of FIG. 3 and the cross-sectional view of FIG. It is configured by forming a comb tooth electrode thereon. 2 and 4 are cross-sectional views taken along lines (A)-(A) of FIGS. 1 and 3, respectively. In the figure, (a) and (c) are electrodes,
(B) represents a photosensitive layer made of a molecular photoconductive material, and (d) represents a substrate. The configuration of the electrodes in these figures is an example, and the present invention is not limited to these. In the configuration of FIG. 1, the electrode (c) may be a strip orthogonal to the electrode (a). In FIG. 3, a strip-shaped gap cast film or a vapor-deposited film of an insulating inorganic material can be used.

[0014] The electrode layer of the optical semiconductor device of the present invention comprises tin,
Indium, aluminum, copper, chromium, titanium,
An electrode made of a metal selected from the group consisting of iron, nickel, and platinum, which may have an oxide layer on its surface, or an electrode made of tin oxide or indium oxide. The electrodes are (a) a metal plate formed of these metals or an alloy containing one or more of these metals; (b) a vapor-deposited film or a sputtered film of a metal formed on a transparent substrate plate such as a polymer film or glass. An electrode layer made of a metal containing at least one of the above-mentioned metals formed by a method such as application of a metal colloid and heat treatment;
On a transparent substrate such as a polymer film or glass,
Tin oxide (NESA) and indium tin oxide (ITO) formed by techniques such as vapor deposition and sputtering
And an electrode layer containing the same. Among these electrode layers, aluminum, copper, platinum, tin oxide (NESA) formed on the surface of a transparent substrate such as an aluminum thin film or a copper thin film; a polymer film or glass by a method such as vapor deposition, ion plating, or sputtering. Alternatively, an electrode made of indium tin oxide (ITO) is preferable.

In the case of a sandwich element in which a molecular photoconductive material is sandwiched between electrodes, the surface to be irradiated with light is preferably a translucent or transparent electrode (metal semi-transparent film, NESA film, ITO film, etc.). . However, when a comb tooth electrode is used, any of the above-mentioned metals or metal oxides can be used, and the electrode need not be translucent.

Further, tin oxide (NES) is used as an electrode layer.
A) When an electrode layer made of indium tin oxide (ITO) is used, the electrode layer formed by a technique such as vapor deposition, ion plating, or sputtering is further treated with an alkali solution, ozone treatment, or ultraviolet light in the presence of oxygen. Alternatively, it is preferable to perform hydrophilic treatment such as irradiation with vacuum ultraviolet light or hydrophilicity by plasma.

The alkali solution treatment includes sodium hydroxide,
It may be immersed in an aqueous solution of lithium hydroxide, potassium hydroxide or the like, an alcohol solution, a mixed solution of water / alcohol, or the like. At this time, the alkali concentration was 0.001 mmol /
Liter to 5 mol / liter, preferably 0.0
A range of 1 mmol / l to 1 mol / l is particularly preferred. The time for the alkali solution treatment is not particularly limited, but when the treatment is performed at room temperature, the time is preferably in the range of 0.5 to 5 hours.

Irradiation with ultraviolet light or vacuum ultraviolet light in the presence of oxygen is performed in a gas containing oxygen at a wavelength of 150 to 380 nm.
May be irradiated for a short time, for example, about 1 minute to 1 hour.

The hydrophilization treatment by plasma may be performed in the presence of oxygen using a dedicated plasma device or sputtering device.

The substrate on which the electrode layer is formed can be made of any material as long as it is insulative. Examples of the material used as the base material include glass, quartz, a plastic film, a metal plate on which a plastic insulating layer is formed, SiO
_And silicon on which ₂ is formed. When light is emitted from the substrate, a transparent substrate is preferably used.

As the photosensitive layer of the optical semiconductor device of the present invention, a photosensitive layer made of a molecular photoconductive material is used, and a charge transport layer is provided on the photosensitive layer made of a molecular photoconductive material. Is also good.

Examples of the molecular photoconductive material include azo pigments, quinone pigments, perylene pigments, indigo pigments, thioindigo pigments, bisbenzimidazole pigments, phthalocyanine pigments, naphthalocyanine pigments, and the like.
Quinacridone-based pigments, quinoline-based pigments, anthraquinone-based pigments, oxazine-based pigments, triphenylmethane-based pigments, azurenium-based dyes, squarylium-based dyes, pyrylium-based dyes, cyanine-based dyes, pyrrolopyrrole-based pigments, and fullerene-based pigments such as C60 and C70 Compounds, and the like, but are not limited thereto. These molecular photoconductive materials can be used alone,
A mixture of more than two kinds of materials can be used. Also,
Among these, phthalocyanine pigments and fullerene compounds are preferred, and oxotitanium phthalocyanine and C60 are particularly preferred.

The photosensitive layer made of a molecular photoconductive material may be formed by forming a film of a molecular photoconductive material by a method such as vacuum deposition, sputtering, or CVD. Particularly preferred is a film of a photoconductive material.

For the vacuum deposition method, a commonly used vacuum deposition apparatus, ultrahigh vacuum deposition apparatus, molecular beam deposition apparatus, or the like can be used. The degree of vacuum at the time of vapor deposition is 10 ⁻² to 10
^-10 Pa is preferable, and 10 ^-2 to 1 in terms of economy.
The range of 0 ^-6 Pa is particularly preferred.

When a photosensitive layer made of a molecular photoconductive material is formed by vapor deposition, there is no particular limitation on the temperature of the substrate during vapor deposition. The substrate temperature is preferably in the range of 0 to 300 ° C, particularly preferably in the range of room temperature to 200 ° C, from the viewpoint of film quality and economy. When phthalocyanines are used as the molecular photoconductive material, it is particularly preferable to heat the substrate to form a crystallized film. In this case, the substrate temperature is preferably 100 ° C. or higher, and particularly preferably 100 to 200 ° C. . Similarly, when using fullerenes, the substrate temperature is 1
It is preferably at least 00 ° C, particularly preferably in the range of 100 to 200 ° C.

When a charge transport layer is formed on a photoconductive layer,
The charge transporting material used for the charge transporting layer is generally classified into a substance that transports electrons and a substance that transports holes, and any of the substances classified into the semiconductor element of the present invention can be used. Such charge transport materials include, for example, chloranyl compounds, tetracyanoquinodimethane compounds, trinitrofluorenone compounds, diphenoquinone compounds, condensed polycyclic aromatic compounds, hydrazone compounds, triphenylamine compounds , A polyvinyl carbazole compound, a polysilane compound, and the like, but are not limited thereto. These charge transport materials can be used alone or in combination of two or more.

The charge transport layer may be formed by dispersing a charge transport material in a binder or by forming the charge transport material into a film by a technique such as vacuum deposition. Membranes are particularly preferred.

When the charge transport material is used by dispersing it in a binder, the binder resin is not particularly limited as long as it has a film-forming property. Examples thereof include polyvinyl resins, polycarbonate resins, and polyester resins. Resin, polyacrylic resin, polymethacrylic resin, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, phenol resin, alkyd resin, polyvinyl Examples include, but are not limited to, butyral, polysulfone, polyurethane, and the like. These binder resins can be used alone or in combination of two or more materials.

In addition to these binder resins, additives such as a plasticizer, a sensitizer, and a surface modifier may be added.

When the charge transporting layer composed of the charge transporting material is formed by coating, a coating material in which the charge transporting material is dispersed or dissolved in a solvent solution of a binder resin is used. In this case, the solvent is not particularly limited as long as the binder resin can be dispersed or dissolved. Generally, since the charge transport layer is formed on the photoconductive layer made of the molecular photoconductive material, when preparing the coating solution for the charge transport layer, a solvent that does not dissolve the molecular photoconductive material or the photosensitive layer is used. Is preferred.

As the solvent used for the solvent solution of the binder resin, for example, methanol, ethanol, propanol,
Alcohols such as pentanol; ketones such as acetone, methyl ethyl ketone, methyl isopropyl ketone and cyclohexanone; dichloromethane, chloroform,
Aliphatic halogenated hydrocarbons such as carbon tetrachloride and 1,1,2-trichloroethane; ethers such as diethyl ether, tetrahydrofuran, 1,4-dioxane, 1,2-dimethoxyethane and diglyme; ethyl acetate and propyl acetate Esters; benzene, toluene, xylene, chlorobenzene, aromatic hydrocarbons such as 1,2-dichlorobenzene; N, N-dimethylformamide;
Non-polar protic solvents such as N, N-dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone,
In actual use, a solvent that satisfies the conditions described above may be appropriately selected from these solvents before use. In addition, these solvents can be used alone or as a mixture of two or more solvents.

As a method of dispersing the charge transport material in the binder resin, for example, a method using a ball meal, a paint conditioner, a sand mill, a kneader, an attritor, a three roll, a jet mill, or the like can be mentioned.

Examples of the method of applying the charge transporting layer made of the charge transporting material include dip coating, spray coating, ring coating, and blade coating.

A feature of the photosemiconductor device of the present invention is that the photosensitive layer made of a molecular photoconductive material is a vapor deposited film obtained by vapor deposition at a vapor deposition rate of 0.07 nm / sec or less. The deposition rate is not particularly limited as long as it is 0.07 nm / sec or less, but when a phthalocyanine-based compound, particularly oxotitanium phthalocyanine (OTiPc) is used, the deposition rate affects the crystallinity and molecular orientation of the deposited film. From these viewpoints, it is particularly preferable to perform deposition at 0.05 nm / sec or less.

[0035]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the invention is not limited to the scope of these examples. In addition, “%” used in the following examples is “% by weight” unless otherwise specified.
Represents

(Example 1) The vertical and horizontal lengths are 20 mm,
Platinum was deposited to a film thickness of 20 nm on a 1 mm thick Pyrex glass by sputtering to produce a translucent platinum electrode.

Built with oil rotary pump and oil diffusion pump
Oxochi purified by sublimation using a vacuum deposition system
Titanium phthalocyanine (OTiPc) is made of alumina
Prepare the crucible and place the above electrode at a position 20 cm above the crucible.
Three substrates are installed and 3 × 10 ^-FourVapor deposition under vacuum of Pa
Was. During the deposition, the electrode substrate was maintained at a temperature of 150 ° C.
The deposition speed should not be observed with a film thickness monitor using a quartz oscillator.
Then, heat the crucible made of alumina to 400 to 450 ° C.
In this way, it was controlled to 0.05 nm / sec. like this
Then, a 250 nm-thick OTiPc vapor-deposited film was
Formed on a plate.

After returning the vapor deposition system to normal pressure, 3 × 1
Under a vacuum of 0 ^-3 Pa, a gold electrode having an active area of 2 × 2 mm is vapor-deposited to a thickness of 20 nm by four elements, and Pyrex glass / platinum (20 nm) / OTiPc (250 nm) /
An optical semiconductor device having a structure of Au (20 nm) was manufactured.

In the X-ray diffraction diagram of the optical semiconductor device thus obtained, the Bragg angle (2θ) is 7.6 degrees (1.16n).
A diffraction peak was observed only in m). This is the α-type OTi
This corresponds to the (010) plane of Pc. Therefore, the α-type crystal b
The axis is oriented substantially perpendicular to the substrate, indicating that the microcrystals forming the deposited film have the same orientation. The absorption maximum of the polarized visible absorption spectrum is 830 nm, and α-type O
It matches TiPc.

The measurement of the dark current and the photocurrent of the optical semiconductor device was performed by the measurement system shown in FIG. The optical semiconductor device was placed in a dark box, and connected to the source measure unit with a lead wire (BNC cable). As the irradiation light, a monochromatic light extracted through a monochromator was irradiated to the active region of the device using a xenon lamp as a light source. While controlling the monochromator and the source measure unit with a personal computer, the light source was turned on and off, the photocurrent and the dark current were measured, and were taken into the personal computer.

A voltage of -5 V is applied to the electrode (c) to turn on the light.
While being turned off, the voltage was swept by 0.5 V and the dark current and the photocurrent-voltage characteristics were measured in the range up to the application of 5 V. At this time,
Monochromatic light having a wavelength of 720 nm and an electrode transmitted light intensity of 0.5 μW / cm ² was used.

FIG. 6 shows the representative current-voltage characteristics. The reproducibility between 3 × 4 elements (12 elements in total) was good. The dark current and the photocurrent showed almost the same values when (-) V was applied and when (+) V was applied. Photocurrent quantum efficiency is +0.5
It starts to exceed 1 from the vicinity of V application and becomes 3 when +5 V is applied.
00 was given. This result clearly indicates photocurrent amplification.

The response speed of photocurrent rise when 5 V was applied to an element using a red LED (oscillation wavelength: 690 nm) having a rise speed of 100 μs was measured.
It reached a constant value after 400 milliseconds (ms).

(Comparative Example 1)
Pyrex glass / platinum (20 nm) / OTiPc (250 nm) in the same manner as in Example 1 except that the vapor deposition rate of c was adjusted so as not to be 0.07 nm / sec or less.
An optical semiconductor device having a structure of / Au (20 nm) was manufactured.

Under the same conditions as in Example 1, the dark current and the photocurrent-voltage characteristics of the optical semiconductor device of Comparative Example 1 were measured.
FIG. 7 shows typical current-voltage characteristics at this time. The dark current and the photocurrent showed almost the same values when (-) V was applied and when (+) V was applied. The dark current and the photocurrent showed almost the same values when (-) V was applied and when (+) V was applied. The photocurrent quantum efficiency did not exceed 1 even when +5 V was applied.

The optical semiconductor device of Example 1 clearly shows the result of photocurrent amplification, while the optical semiconductor device of Comparative Example 1 in which a photoconductive material was vapor-deposited at a high speed,
Obviously, no amplification of photocurrent has occurred, and from these results, the effect of low-speed deposition at 0.07 nm / sec or less is clear.

(Embodiment 2) The vertical and horizontal lengths are 20 mm,
3 × 10 on Pyrex glass 1mm thick ^-3Pa
Vacuum is deposited to a thickness of 20 nm under a vacuum of
A bright electrode was obtained.

Sublimated and purified oxotitanium phthalocyanine (OTiPc) was charged into a quartz Knudsen cell using a vacuum evaporation system constructed with an oil rotary pump and a turbo molecular pump, and the 20 c
a distance of m, was placed one sheet of the electrode substrate, 2 × 10 ^-5 P
The deposition was performed under the vacuum of a. During deposition, the electrode substrate is 150
C. and maintained at a temperature of 230 ° C. while monitoring the deposition rate with a film thickness monitor using a quartz oscillator.
The temperature was controlled at 0.05 nm / sec by heating to 70 ° C. Thus, a 200 nm-thick OtTiPc deposited film was formed. After the substrate temperature was brought to room temperature, 4,4 ′-(phenyl, 2-methylphenylamino) was obtained under the same conditions.
Biphenyl was deposited to a thickness of 50 nm.

After returning to normal pressure, the gold electrode having an active area of 2 × 2 mm was placed under a vacuum of 3 × 10 ⁻³ Pa at 20 nm.
Of Pyrex glass / copper (20 nm) / OTiPc (200 nm) / 4,4'-
An optical semiconductor device having a configuration of (phenyl, 2-methylphenylamino) biphenyl (50 nm) / Au (20 nm) was manufactured.

In the X-ray diffraction diagram of the optical semiconductor device thus obtained, the Bragg angle (2θ) is 7.6 degrees (1.16n).
A diffraction peak was observed only in m). This is the α-type OTi
This corresponds to the (010) plane of Pc. Therefore, the α-type crystal b
The axis is oriented substantially perpendicular to the substrate, indicating that the microcrystals forming the deposited film have the same orientation. The absorption maximum of the polarized visible absorption spectrum is 830 nm, and α-type O
It matches TiPc.

The dark current and the photocurrent of the optical semiconductor device were measured in the same manner as in Experimental Example 1 except that monochromatic light having a wavelength of 720 nm and an electrode transmitted light intensity of 0.5 μW / cm ² was used. As a result, the photocurrent quantum efficiency was 500 when +5 V was applied, indicating that photocurrent amplification was apparently occurring.

(Comparative Example 2) In Example 2, the OTiP
Pyrex glass / copper (20 nm) / OTiPc (200 nm) / 200 nm in the same manner as in Example 2 except that the deposition rate of c was adjusted so as not to be 0.07 nm / sec or less.
An optical semiconductor device having a configuration of 4,4 ′-(phenyl, 2-methylphenylamino) biphenyl (50 nm) / Au (20 nm) was manufactured. Dark current and photocurrent are (-) V
The values were almost the same between when the voltage was applied and when (+) V was applied.

Under the same conditions as in Example 2, the dark current and the photocurrent-voltage characteristics of the optical semiconductor device of Comparative Example 2 were measured.
As a result, the photocurrent quantum efficiency did not exceed 1 even when +5 V was applied, and no photocurrent amplification phenomenon was observed.

(Embodiment 3) The vertical and horizontal lengths are 20 mm,
3 × 10 on Pyrex glass 1mm thick ^-3Pa
Vacuum is deposited to a thickness of 20 nm under a vacuum of
A bright electrode was obtained.

Using an evaporation apparatus having a vacuum system constructed by an oil rotary pump and a turbo molecular pump, sublimated and refined oxotitanium phthalocyanine (OTiPc) was charged into a Knudsen cell made of quartz, and 20 c on the Knoon cell.
a distance of m, was placed one sheet of the electrode substrate, 2 × 10 ^-5 P
The deposition was performed under the vacuum of a. During deposition, the electrode substrate is 150
C. and maintained at a temperature of 230 ° C. while monitoring the deposition rate with a film thickness monitor using a quartz oscillator.
The temperature was controlled at 0.05 nm / sec by heating to 70 ° C. In this way, a 250 nm-thick OtTiPc deposited film was formed.

After the pressure was once returned to normal pressure, the gold electrode having an active area of 2 × 2 mm was placed under a vacuum of 3 × 10 ⁻³ Pa at 20 nm.
Of Pyrex glass / copper (20 nm) / OTiPc (250 nm) / Au (20
nm) was fabricated.

In the X-ray diffraction diagram of the optical semiconductor device thus obtained, the Bragg angle (2θ) is 7.6 degrees (1.16n).
A diffraction peak was observed only in m). This is the α-type OTi
This corresponds to the (010) plane of Pc. Therefore, the α-type crystal b
The axis is oriented substantially perpendicular to the substrate, indicating that the microcrystals forming the deposited film have the same orientation. The absorption maximum of the polarized visible absorption spectrum is 830 nm, and α-type O
It matches TiPc.

The dark current and the photocurrent of the optical semiconductor device were measured in the same manner as in Experimental Example 1, except that monochromatic light having a wavelength of 720 nm and an electrode transmitted light intensity of 0.5 μW / cm ² was used. As a result, the photocurrent quantum efficiency was 500 when +5 V was applied, indicating that photocurrent amplification was apparently occurring.

(Comparative Example 3) In Example 3, the OTiP
Pyrex glass / copper (20 nm) / OTiPc (250 nm) / same as in Example 3 except that the vapor deposition rate of c was adjusted so as not to be 0.07 nm / sec or less.
An optical semiconductor device having a structure of Au (20 nm) was manufactured. The dark current and the photocurrent showed almost the same values when (-) V was applied and when (+) V was applied.

Under the same conditions as in Example 3, the dark current and the photocurrent-voltage characteristics of the optical semiconductor device of Comparative Example 3 were measured.
As a result, the photocurrent quantum efficiency did not exceed 1 even when +5 V was applied, and no photocurrent amplification phenomenon was observed.

Example 4 An electrode layer of Pyrex glass / platinum was produced in the same manner as in Experimental Example 1. Using the same deposition apparatus as in Example 1, a C60 deposited film was formed to a thickness of 400 nm under the same conditions. Once the pressure is returned to normal pressure, a gold electrode having an active area of 2 × 2 mm is vapor-deposited to a thickness of 20 nm by four elements under vacuum of 3 × 10 ⁻³ Pa, and Pyrex glass / platinum (20 nm) / C60 (400n
An optical semiconductor device having a configuration of m) / Au (20 nm) was manufactured.

In the X-ray diffraction diagram of the optical semiconductor device thus obtained, the Bragg angle (2θ) is 10.71 degrees, and 17.
A diffraction pattern was shown at 62 degrees and 20.72 degrees, and crystals having an fcc structure were formed.

The dark current and the photocurrent of the optical semiconductor device were measured in the same manner as in Experimental Example 1, except that monochromatic light having a wavelength of 400 nm and an electrode transmitted light intensity of 1.27 μW / cm ² was used. As a result, when +8 V was applied, the photocurrent quantum efficiency was 40, indicating that photocurrent amplification was apparently occurring.

Comparative Example 4 Pyrex glass / platinum (20 nm) / C60 was prepared in the same manner as in Example 4 except that the deposition rate of C60 was adjusted so as not to be not more than 0.07 nm / sec. (400 nm) / Au
An optical semiconductor device having a (20 nm) configuration was manufactured.
The dark current and the photocurrent showed almost the same values when (-) V was applied and when (+) V was applied.

Under the same conditions as in Example 1, the dark current and the photocurrent-voltage characteristics of the optical semiconductor device of Comparative Example 4 were measured.
As a result, the photocurrent quantum efficiency did not exceed 1 even when +8 V was applied, and no photocurrent amplification phenomenon was observed.

Example 5 An indium tin oxide electrode layer having a thickness of 40 nm formed by sputtering (hereinafter referred to as “indium tin oxide electrode layer”)
Abbreviated as ITO. Substituted and purified oxotitanium phthalocyanine (OTiPc) in the same manner as in Example 1 on a 1 mm thick Pyrex glass substrate having
A film was formed to a thickness of 250 nm, and a gold electrode was formed to a thickness of 20 nm in the same manner as in Example 1, and pyrex glass / ITO (40 nm) / OTiPc (250 nm) / A
An optical semiconductor device having a u (20 nm) configuration was manufactured.

Wavelength 7 at an electrode transmitted light intensity of 20 μW / cm ²
The dark current and the photocurrent of the optical semiconductor device were measured in the same manner as in Example 1 except that the monochromatic light of 20 nm was used.
As a result, the photocurrent quantum efficiency was 35 at the time of applying -3 V.
Which clearly indicated that photocurrent amplification was occurring.

(Comparative Example 5) In Example 5, the OTiP
Pyrex glass / ITO (40 nm) / OTiPc (250 n) in the same manner as in Example 5 except that the vapor deposition rate of c was adjusted so as not to be 0.07 nm / sec or less.
An optical semiconductor device having a configuration of m) / Au (20 nm) was manufactured. The dark current and the photocurrent are (−) V applied and (+) V applied.
The values were almost the same at the time of application.

Under the same conditions as in Example 5, the dark current and the photocurrent-voltage characteristics of the optical semiconductor device of Comparative Example 5 were measured.
As a result, the photocurrent quantum efficiency did not exceed 1 even when -3 V was applied, and no photocurrent amplification phenomenon was observed.

(Example 6) A Pyrex glass substrate (hereinafter abbreviated as ITO) having a thickness of 1 mm having an indium tin oxide electrode layer having a thickness of 40 nm formed by sputtering was prepared in the same manner as in Example 1. Sublimated and purified oxotitanium phthalocyanine (OTiPc) was formed to a film thickness of 200 nm.
4,4 ′-(phenyl, 2-methylphenylamino) biphenyl is deposited to a thickness of 50 nm, a gold electrode is formed to a thickness of 20 nm, and Pyrex glass / ITO (40 nm) /
Otipc (200 nm) / 4,4 '-(phenyl, 2
-Methylphenylamino) biphenyl (50 nm) / A
An optical semiconductor device having a u (20 nm) configuration was manufactured.

Wavelength 7 of ²⁰ μW / cm ² transmitted light intensity of electrode
The dark current and the photocurrent of the optical semiconductor device were measured in the same manner as in Example 1 except that the monochromatic light of 20 nm was used.
As a result, the photocurrent quantum efficiency was 35 at the time of applying -3 V.
Which clearly indicated that photocurrent amplification was occurring.

(Comparative Example 6) In Example 5, the OTiP
Pyrex glass / ITO (40 nm) / OTiPc (200 n) in the same manner as in Example 5 except that the vapor deposition rate of c was adjusted so as not to be 0.07 nm / sec or less.
m) / 4, 4 ′-(phenyl, 2-methylphenylamino) biphenyl (50 nm) / Au (20 nm) was produced. The dark current and the photocurrent showed almost the same values when (-) V was applied and when (+) V was applied.

Under the same conditions as in Example 6, the dark current and the photocurrent-voltage characteristics of the optical semiconductor device of Comparative Example 6 were measured.
As a result, the photocurrent quantum efficiency did not exceed 1 even when -3 V was applied, and no photocurrent amplification phenomenon was observed.

[0074]

The optical semiconductor device according to the present invention is selected from the group consisting of tin, indium, aluminum, copper, chromium, titanium, iron, nickel and platinum which may have an oxide layer on the surface as an electrode layer. An electrode layer made of a selected material, or a tin oxide or indium tin oxide electrode layer is adopted, and as a photosensitive layer, a deposited film obtained by depositing a molecular photoconductive material at a deposition rate of 0.07 nm / sec or less is used. By using this, even if a self-assembled film is not formed on the electrode layer, the sensitivity is improved until the photocurrent quantum efficiency shows amplification exceeding 1, and the reproducibility is also excellent.

[Brief description of the drawings]

FIG. 1 is a plan view showing one type of an optical semiconductor device of the present invention.

[Explanation of symbols]

 a electrode b film made of molecular photoconductive material

FIG. 2 is a plan view of the optical semiconductor device shown in FIG.
It is sectional drawing which follows the (A)-(A) line.

[Explanation of symbols]

 a electrode b film made of molecular photoconductive material c electrode d substrate

FIG. 3 is a plan view showing one type of the optical semiconductor device of the present invention.

[Explanation of symbols]

 a electrode b film made of molecular photoconductive material c electrode

4 is a plan view of the optical semiconductor device shown in FIG.
It is sectional drawing which follows the (A)-(A) line.

[Explanation of symbols]

 a electrode b film made of molecular photoconductive material c electrode d substrate

FIG. 5 is a schematic diagram of a measurement system for measuring a dark current and a photocurrent of an optical semiconductor device.

[Explanation of symbols]

 a Electrode b Film made of molecular photoconductive material c Electrode d Substrate f Source measure unit g Monochromator h Xenon lamp i Personal computer j Monochromatic light irradiated to element k Lead wire l GPIB cable

FIG. 6 shows an applied voltage of the optical semiconductor device shown in the first embodiment,
5 is a table showing a relationship between dark current, photocurrent-voltage response, and photoelectron quantum efficiency.

[Explanation of symbols]

 Photocurrent ● Dark current ▲ Photocurrent quantum efficiency

FIG. 7 shows an applied voltage of the optical semiconductor device shown in Comparative Example 1,
5 is a table showing a relationship between dark current, photocurrent-voltage response, and photoelectron quantum efficiency.

[Explanation of symbols]

 Photocurrent ● Dark current ▲ Photocurrent quantum efficiency

Claims (3)

[Claims] 1. An optical semiconductor device having a photosensitive layer composed of an organic vapor-deposited film between two electrode layers, wherein the electrode layer may have an oxide layer on its surface, tin, indium, aluminum, copper, and chromium. An electrode layer made of a material selected from the group consisting of titanium, iron, nickel and platinum, or a tin oxide or indium tin oxide electrode layer, wherein the photosensitive layer is formed of a molecular photoconductive material at a deposition rate of 0.07 nm / sec or less. An optical semiconductor element, which is a deposited film obtained by vapor deposition. 2. The optical semiconductor device according to claim 1, wherein the deposited film is obtained by vapor deposition at an electrode layer surface temperature of 100 ° C. or higher. 3. The optical semiconductor device according to claim 1, wherein the molecular photoconductive material is a material selected from the group consisting of phthalocyanines and fullerenes.