JP3405099B2 - Color sensor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color sensor, and more particularly, it includes an optoelectronic material containing ultrafine particles such as semiconductors having a controllable particle size, which is formed from a material having an inexhaustible reserve and free of environmental pollution. Silicon (Si) -LSI
The present invention relates to a color sensor including an optoelectronic material having excellent characteristics in technical consistency, self-luminous property, high-speed response, fine pixel property, low power consumption, high environmental resistance, and assemblyless process.

[0002]

2. Description of the Related Art Conventionally, since silicon (Si) is an indirect transition type semiconductor and has a bandgap of 1.1 eV in the near infrared region, it is impossible to realize a light emitting element or a light receiving element in the visible light region. Has been said to be. Therefore, compound semiconductors centering on the III-V group or the II-VI group have been used as the light emitting element.

Therefore, first, as a first conventional example, a light emitting element using a compound semiconductor will be described.

Direct transition semiconductor gallium arsenide (G
If a pn junction is formed using a compound semiconductor such as aAs) and a forward voltage is applied as a diode, electrons drifting to the p-type region as minority carriers and holes which are majority carriers in the p-type region are formed. Radiative recombination efficiently occurs in the vicinity of the pn junction surface, so that light emission is possible. This is a so-called injection type LED (Light Emitting D).
iode) principle. The emission wavelength of this LED is determined by the type of semiconductor that constitutes it.

On the other hand, room temperature visible light emission of porous Si was confirmed in 1990 (for example, "Applied Physics Letters" (LT Canham, Applie).
dPhysics Letters Vol. 57, N
o. 10, 1046 (1990)) and the like. ), Research on visible light emission characteristics at room temperature using Si as a base material has become popular. Since most of these reports are related to porous Si, this luminescent porous Si will be described as a second conventional example.

This luminescent porous Si is basically formed by anodizing the surface of a single crystal Si substrate in a solution mainly containing hydrogen fluoride.
Photoluminescence (PL) of several wavelengths in the region of 00 nm (red) to 425 nm (blue) has been confirmed. Further, recently, attempts have been made to emit light by current injection excitation (electroluminescence; EL).

This technique is disclosed, for example, in Japanese Patent Laid-Open No. 5-2.
Although it is described in Japanese Patent Publication No. 06514, it will be specifically described with reference to FIG.

FIG. 15 shows a conventional EL using porous Si.
The cross-sectional structure of an element is shown. In FIG. 15, first, a porous Si layer 152 is formed on a surface of a p-type conductive Si single crystal substrate 151 having a plane orientation (100) by anodizing in a hydrogen fluoride solution diluted with ethanol. Form.
Then, an n-type conductive microcrystalline silicon carbide (SiC) thin film 153 is deposited by plasma CVD. Finally, an indium oxide-tin (ITO) thin film 154, which is a semitransparent electrode, is arranged on the upper part, and a metal electrode 155 is arranged on the lower part, and ohmic contacts are formed to complete the process.

The porous Si region 152 is a p-type composed of an n-type SiC thin film 153 and a p-type Si substrate 151.
Since it exists in the n-junction region, electrons are emitted from the n-type region and p
By injecting holes from the − type region and recombining them inside the porous Si region 152, light emission is possible.

The characteristic properties of these porous Si ELs are as follows. (1) EL and PL
Even if the emission spectra of are different in intensity,
It has almost the same shape. (2) The emission intensity of EL is proportional to the injection current in the injection current density region that is assumed to be in actual use. However, there is also an example in which the emission intensity of EL is proportional to the square of the injection current in the region where the injection current density is lower than this.

(1) suggests that the luminescence of EL and PL is generated by the recombination of carriers (excited electron-hole pairs) through almost the same luminescence level, and (2) shows that It is shown that the generation of indispensable carriers is mainly performed by the injection of minority carriers near the pn junction.

Regarding the light emission mechanism of Si, which is an indirect transition type semiconductor, in the three-dimensional nanostructure region of the nanometer (nm) order of the porous shape, relaxation of the wave number selection rule of optical transition occurs, and electron-positive According to the theory that the radiative recombination process of pore pairs is possible, a multi-membered ring oxide of Si (siloxene) is formed on the surface of porous Si, and this siloxene /
There is a theory that a new energy level that contributes to the radiative recombination process is formed at the Si interface. However, in any case, regarding the photoexcitation process, it seems certain that the energy band structure change (gap width increase phenomenon) occurs due to the quantum confinement effect.

A comprehensive description of this area is given, for example,
"Porous Silicon" (ZC Feng and
R. Tsu ed., "Porous Silicon",
It is disclosed in World Scientific (1994)).

Further, the light emission from the porous Si has a broad spectrum width of approximately 0.3 eV or more. Therefore, a cavity structure is formed using this porous Si,
Attempts have been made to enhance the intensity in a specific wavelength region of the original continuous spectrum. Therefore, this technique will be described as a third conventional example.

Regarding this technique, for example, "Applied Physics Letters" (L. Pavesi e.
t al. , Applied Physics Le
terts Vol. 67, 3280 (1995)).

A detailed description will be given below with reference to FIG.
FIG. 16 is a structural sectional view of a conventional light emitting device using porous Si. In FIG. 16, 161 is a p-type Si substrate,
162 and 164 are multilayer reflective film layers, 163 is an active layer, and both the multilayer reflective film layer and the active layer are made of porous Si. In the configuration of this figure, first, the p-type Si substrate 16
When 1 is anodized, the formation time and the current density are alternately changed to form 6 pairs of porous Si layers having different refractive indexes to form a multilayer reflective film layer 162. The optical film thickness (refractive index × film thickness) of each layer of the multilayer reflective film layer 162 is set to ¼ of the emission wavelength (λ). Next, the active layer 163 is formed by performing anodization under conditions different from those for forming the above multilayer reflective film layer. This active layer 163
The optical film thickness of is set to λ. Furthermore, the multilayer reflective film layer 1
A multilayer reflective film layer 164 similar to 62 is formed.

Next, the operation principle of light emission in the light emitting device having the above structure will be described. First, an argon ion (Ar ⁺ ) laser beam (wavelength: 488) was applied to the light emitting device.
(nm), it emits light in a direction perpendicular to the surface. A typical emission spectrum of the active layer 103 alone is 7
The peak at 50 nm and the full width at half maximum of the spectrum is 130.
The emission spectrum obtained by this light emitting device has a peak wavelength similar to 750 nm, but has a full width at half maximum of 15 nm (34 meV), which is very narrow. ing. Further, in the emission spectrum of this light emitting element, the emission intensity at the peak wavelength is increased. This is due to the cavity structure formed by the active layer and the multilayer reflective film layer,
This is because the light emitted from the active layer undergoes multiple interference and only the emission intensity in the wavelength region having a peak at λ is enhanced.

On the other hand, semiconductors are also widely used as photoelectric conversion elements. Therefore, as a fourth conventional example, a photodiode will be described as a photoelectric conversion element using a semiconductor.

FIG. 17 is a structural sectional view of a conventional photodiode. In FIG. 17, p-type region layer 171 and n
The mold region layer 172 forms a pn junction. For example,
In the case of Si photodiode, for n-type substrate,
The p-type region layer 171 is formed to a thickness of 1 μm or less by selective diffusion of boron.

Next, the operation principle of light reception in the photodiode having the above structure will be described.

In this photodiode, when a pn junction is irradiated with light having a photon energy larger than the band gap energy (Eg) of the semiconductor forming the photodiode, carriers of electron-hole pairs are generated. By detecting the photoelectromotive force by this, it has a light receiving function. The spectral sensitivity is determined by the type of semiconductor that constitutes it. For example, in the case of a Si photodiode, E
Since g is 1.1 eV, it has photosensitivity in a wide wavelength range from ultraviolet rays to near infrared rays.

Finally, as a fifth conventional example, a color sensor using the above photodiode will be described.

FIG. 18 shows a sectional structure of a conventional integrated single plate type color sensor. This color sensor is, in principle, an integrated monochromatic sensor divided into three colors R, G, and B. In FIG. 18, 181, 182, 183
Are photodiodes corresponding to R, G, and B, respectively, and 184 is composed of three color filters corresponding to R, G, and B.

Next, the operation principle of light reception in the color sensor having the above structure will be described.

When, for example, red (R) light is applied to this color sensor, only the portion of the color filter 184 corresponding to R is transmitted and the photodiode 1
At 81, a carrier of an electron-hole pair is generated, and a photoelectromotive force caused by the carrier is detected to have a light receiving function. Similarly, the photodiodes 182 and 183 have sensitivity to G and B, respectively. Furthermore, by appropriately performing arithmetic processing on these three primary colors, it is possible to identify 12 or more colors including intermediate colors.

[0026]

However, as seen in the first conventional example, the direct transition type III-V is used.
In the case of being composed of a compound semiconductor centered on Group II or Group II-VI, the luminous efficiency is high, but harmful substances (C
d, As, etc.), or a material (In, etc.) with a very small reserve and high purification cost. Further, as compared with Si, the fine processing technology as a semiconductor manufacturing process technology for these compound semiconductors is not yet matured, so that it is difficult to form a fine pattern of micron (μm) or less. Further, the group III element and the group V element each act as a dopant in Si and thus affect the conductivity. That is, although a self-luminous element is mainly composed of a semiconductor material, Si-
It can be said that it is impossible to manufacture an element substantially integrated with the Si-LSI because the compatibility with the process / device technology of the LSI is poor. Further, as an essential problem, there is a problem that in order to adjust the emission wavelength, the material type must be changed (that is, a new search) and the manufacturing method must be reconstructed throughout.

Next, in the case of the second conventional technique,
Since the porous layer is formed on the surface of the single crystal Si substrate by anodization in the solution, the crystallinity of the microcrystal in the porous layer is good, but the shape and size of the microcrystal should be controlled. Is difficult. In particular, it is difficult to efficiently generate spherical microcrystals having a grain size of 5 nm or less. If the visible light emission mechanism in the Si-based group IV material is the quantum size effect (relaxation of the wave number selection rule, band structure change due to the quantum confinement effect, etc.), the formation of spherical fine particles whose particle size is controlled at the nm level also occurs. Although it is indispensable, judging from this point, it cannot be said that it is an optimum manufacturing technique. Further, when the light emitting elements made of porous Si are regularly arranged and independently operated, it is difficult to perform the function of the display element. That is, the above-mentioned porous Si
Since it is directly formed on the Si substrate, it is impossible to maintain electrical independence (insulation) between each element.

Furthermore, an LED composed of a semiconductor
Has a wide spectral width. Therefore, in the third conventional example, a cavity structure is formed to narrow the spectral width, but since the layers forming the periodic structure are all made of porous Si, absorption in the visible light region is considered. Is large,
As a result, the luminous efficiency becomes low. However, since the porous Si is directly formed in the Si substrate as described above, it is impossible to form a laminated structure with another substance such as a transparent material having a high transmittance in the visible range.

On the other hand, the fourth conventional example has a problem that the material type must be changed in order to adjust the light receiving wavelength in the first place, and when the compound semiconductor is used, the first conventional example is required. It has the same problems as those that occur in.
In addition, since the photoelectric conversion element simply using Si has sensitivity in the entire visible light region, in order to adjust the received light wavelength,
It needs to go through a color filter.

Furthermore, when the photoelectric conversion element described in the fourth conventional example is used as an ultraviolet sensor, since the absorption coefficient of Si in this wavelength region is large, the pn junction is formed in a very shallow portion. Have the task of having to.

Further, in the fifth conventional example, it is necessary to use a color filter in order to discriminate a color as a color sensor after all, an assembly process cannot be avoided, and Si is used.
-Inconsistency with LSI process / device technology
It can be said that it is impossible to manufacture an element substantially integrated with the Si-LSI. Furthermore, since the elements corresponding to the three primary colors are arranged in a plane, there is a problem that the substantial light receiving sensitivity is low.

The present invention has been made in view of the above-mentioned problems, and is an optoelectronic material which has an inexhaustible amount of reserves and is free of environmental pollution, and which has Si-LSI technical compatibility, environmental resistance, and assembly-less property. An object of the present invention is to provide a simple color sensor that does not require a color filter or the like by using.

[0033]

In order to solve the above problems, the color sensor of the present invention includes an optoelectronic material dispersed in a substantially homogeneous medium whose electrical properties such as conductivity can be controlled. By having a photoelectron material layer and a pair of electrodes provided above and below the optoelectronic material layer, by detecting changes in internal resistance due to carrier generation corresponding to light irradiation to the optoelectronic material layer and photoelectromotive force A photoelectric conversion layer having a light-receiving function, by controlling the optical gap energy of ultrafine particles, photoelectric conversion layers having a light-receiving function in mutually different predetermined wavelength regions are laminated via a transparent insulator film. Has a configuration.

With such a structure, it is necessary to provide a color filter or the like by using an optoelectronic material which has an inexhaustible reserve and is free of environmental pollution, and which has Si-LSI technical compatibility, environmental resistance, and assembly-less property. It is possible to provide a color sensor having a simple structure with no problem.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention according to claim 1 provides an optoelectronic material layer containing an optoelectronic material in which ultrafine particles are dispersed in a substantially homogeneous medium whose conductivity or permittivity is controllable. A photoelectric conversion layer having a pair of electrodes provided above and below the optoelectronic material layer and having a light receiving function by detecting a change in internal resistance due to carrier generation corresponding to light irradiation to the optoelectronic material layer. By adjusting the average particle size of the ultrafine particles or the structure of the surface atomic arrangement to control the optical gap energy, the photoelectric conversion layer having a light receiving function in different predetermined wavelength regions,
It is a color sensor that is laminated via a transparent insulator film.

With such a structure, when light is irradiated, the internal resistance of the optoelectronic material layer sensitive to the wavelength component changes, and photoelectric conversion corresponding to the wavelength is performed by using the internal resistance change. , Acts as a color sensor.

An optoelectronic material layer containing an optoelectronic material in which ultrafine particles are dispersed in a substantially homogeneous medium whose electric conductivity or dielectric constant is controllable,
A pair of electrodes provided above and below the optoelectronic material layer, and a Schottky junction at the interface between the optoelectronic material layer and the electrode, or a pn inside the optoelectronic material layer.
A photoelectric conversion layer in which a junction is formed and has a light receiving function by detecting a photoelectromotive force due to generation of carriers by light irradiation, and an optical structure is formed by adjusting the average particle size of the ultrafine particles or the structure of surface atomic arrangement. A color sensor in which the photoelectric conversion layers having a light receiving function in predetermined wavelength regions different from each other by controlling the gap energy are stacked via a transparent insulating film may be used.

With such a structure, when light is irradiated, an electromotive force is generated in the optoelectronic material layer sensitive to the wavelength component, and the electromotive force is used to perform photoelectric conversion corresponding to the wavelength. , Acts as a color sensor.

Here, when the minority carriers are injected into the ultrafine particles of the photoelectron material layer by the pair of electrodes, the photoelectric conversion layer emits the generated electron-hole pairs. It may also have a light emitting function of exhibiting a light emitting phenomenon by the recombination process.

Further, as described in claim 4, it is preferable that the stacked photoelectric conversion layers have different optical gap energies from each other, and that the closer the light receiving surface is, the larger the optical gap energy is, in view of the light receiving sensitivity. Is.

Further, the photoelectric conversion layer may be three layers having different optical gap energies in the visible light region as described in claim 5.

Further, it is preferable that the pair of electrodes are transparent or semitransparent in terms of light receiving efficiency.

On the other hand, the ultrafine particles are not only a group IV semiconductor as described in claim 7 or 8, but also III-
It can be configured even if it includes a group V or group II-VI compound semiconductor.

Further, the medium may be a thin film conductor as described in claim 9, or a thin film dielectric as described in claim 10.

Further, as described in claim 11, in the optoelectronic material layer, the ultrafine particles are dispersed in a substantially homogeneous medium in which the electric conductivity or the permittivity is controllable, and the ultrafine particle dispersed. It may have a periodic structure in which layers and transparent material layers are alternately laminated, and the light receiving wavelength is narrowed and the light receiving sensitivity is increased.

The transparent material layer may be a conductor thin film or a dielectric thin film.

According to a fourteenth aspect of the present invention, the optoelectronic material layer comprises an active layer containing ultrafine particles, a high reflection layer provided below the active layer, and a portion provided above the active layer. A structure having a reflection layer may be used, and the light receiving wavelength is narrowed and the light receiving sensitivity is increased.

Here, as described in claim 15, at least one of the partial reflection layer and the high reflection layer may be a metal thin film, and as described in claim 16, at least two kinds of different refractive indexes are provided. It may be a multilayer film layer having a periodic structure in which layers are alternately laminated.

According to a seventeenth aspect of the present invention, the high reflection layer has a multilayer film layer having a periodic structure in which at least two types of layers having different refractive indexes are alternately laminated, and a metal thin film layer. Good.

Further, in the optoelectronic material described above, the first target material arranging step of arranging the first target material inside the vacuum reaction chamber in a low-pressure rare gas atmosphere, and the deposition substrate are provided. A step of arranging the substrate inside the vacuum reaction chamber, and a step of arranging a second target material inside the reaction chamber separated from the first target material and the deposition substrate as an atmospheric component, Desorption of the target material by irradiating the first target material arranged in the first target material arrangement step with laser light
An ablation process that causes injection and an evaporation process that evaporates the second target material arranged in the second target material arranging process, and the substance desorbed and injected in the ablation process is condensed in air. Substantially at the same time that the ultrafine particles obtained by the growth are collected on the deposition substrate, the substances generated in the evaporation step are collected on the deposition substrate, and the ultrafine particles are collected from the second target material. It is preferably obtained by a production method for obtaining an optoelectronic material in which the ultrafine particles are dispersed in a constituent substance.

Then, in the evaporation step of evaporating the second target material, it is preferable that the second target material is evaporated by using a laser.
More specifically, as in claim 20, in the evaporation step of evaporating the second target material, the second target material is irradiated with a second laser beam to release the target material.
It is preferred to include an ablation step that causes injection.

Further, as described in claim 21, it is preferable that the first target material contains a semiconductor, and as described in claim 22 or 23, the second target material may be a conductor. However, it may be a dielectric.

Here, in order to appropriately adjust the light-receiving wavelength and the like, it is preferable to control the received photon energy by adjusting the particle diameter of the ultrafine particles as described in claim 24.

It is preferable that the control of the ultrafine particles is performed by the step of changing the introduction pressure of the low pressure rare gas as described in claim 25.

Alternatively, the average particle diameter of the ultrafine particles may be controlled by a step of mass-separating the ultrafine particles obtained by the ablation step as described in claim 26. 27, the step of mass-separating the ultrafine particles includes a step of ionizing the ultrafine particles,
Those including a step of applying an electric field or magnetic field to the ionized ultrafine particles are preferable.

Alternatively, as described in claim 28, the photon energy of the received light may be controlled by adjusting the structure of the surface atom arrangement of the ultrafine particles.

(Example of Color Sensor) A color sensor using the optoelectronic material of the present invention will be described below. As a premise of this, in order to explain the principle of the function of the optoelectronic material containing ultrafine particles. First, among light-emitting devices, particularly in group IV semiconductors, ultrafine particles of Si whose surface is typically coated with its own thermal oxide film are homogeneous transparent media whose conductivity or dielectric constant can be controlled. An electroluminescence (EL) device in which a photoelectron material layer dispersed therein is used as a light emitting (active) region will be described.

Here, in some cases, the oxide film of ultrafine particles may be omitted. Further, a homogeneous medium means that the electrical properties in the medium, in particular the electric conductivity and the permittivity, are almost uniform in the medium, and the number of ultrafine particles dispersed in the medium is several tens to several hundreds. While the medium itself is an aggregate of atoms and molecules, the medium itself is formed by stacking several smaller aggregates of atoms and molecules on a prescribed substrate, etc. Is given as an example.

FIG. 1 shows a sectional structure of a light emitting device using an optoelectronic material. In FIG. 1, reference numeral 11 is a substrate. As the substrate 11, a p-type Si substrate having a plane orientation (100), a conductivity of boron-doped p-type, and a specific resistance of 10 Ω · cm was used as an example. An isolation insulating film 12, which is a silicon dioxide (SiO ₂ ) film as an example, is formed on the upper surface of the p − type Si substrate 11 to have a thickness of 100 nm. In this isolation insulating film 12, an opening 12a having a diameter of about 1 to 2 mm is formed at a position to be a light emitting (active) region of the light emitting element, and the surface of the substrate 11 is exposed.

Then, the optoelectronic material layer 13 is deposited so as to cover at least the opening 12a. This optoelectronic material layer 13 is formed of the Si ultrafine particles 1 as described above.
4 are dispersed in a homogeneous transparent medium 15. Here, the Si ultrafine particles 14 are substantially spherical in shape, have the same crystallinity as the crystallinity of bulk Si, and have p-type conductivity in which boron is doped at a low concentration. The particle size is adjusted to about 3 to 10 nm. Further, the surface of the Si ultrafine particles 14 is covered with a SiO ₂ film (not shown) having a thickness of 1 to 5 nm. Further, the transparent medium 15 is a homogeneous thin film having a high transmittance in the visible light region and a controllable electric conductivity or dielectric constant,
Here, as an example, a tin oxide (SnO ₂ ) thin film was used. This SnO ₂ thin film has a visible light transmittance of 80% or more, and the conductivity or the dielectric constant can be controlled by adjusting the manufacturing conditions (substrate temperature, oxygen partial pressure, etc.). Therefore, for example, if the specific resistance of the Si ultrafine particles is about 10 Ω · cm, the specific resistance of the SnO ₂ thin film can be controlled within the range of about 1 to 10 ³ Ω · cm. It is possible to control injection and quantum confinement effect of carriers in ultrafine particles.

Although Si is used here as the material of the ultrafine particles forming the optoelectronic material layer, other group IV semiconductors such as germanium (Ge) or a mixed crystal thereof can be preferably used, and III-V A group II-VI compound semiconductor may be used. And, as a homogeneous transparent medium, Sn
Although the O ₂ thin film was used, another conductive thin film having a specific resistance equal to or higher than the specific resistance of the ultrafine particles to be dispersed, for example, titanium oxide (TiO ₂ ), indium oxide (InO ₂ ), indium oxide- A tin (ITO) thin film may be used. Alternatively, if the film thickness is within a range in which electric conduction by tunneling or hopping is possible, SiO ₂ ,
It is also possible to use a dielectric thin film such as aluminum oxide (Al ₂ O ₃ ).

Further, as an example, a semi-transparent electrode 16 having a thickness of 10 nm and made of platinum (Pt) is brought into contact with the upper surface of the optoelectronic material layer 13, and the transparent medium 1 whose conductivity is controlled.
A so-called Schottky junction is electrically formed with the optoelectronic material layer 13 containing 5 A back electrode 17 made of Pt, for example, is provided on the lower surface of the substrate 11 to electrically form an ohmic contact with the substrate 11.

The electrodes 16 and 17 are not limited to Pt.
It is also possible to mainly form any of aluminum, gold, silver, tungsten, molybdenum, tantalum, and the like.

Then, the semitransparent electrode 16 and the back electrode 17
Is connected to a power source by a wire lead wire or the like through the conductive paste 18 or the like as necessary. Here, it is preferable that the position of the conductive paste 18 which is the power source connection position on the side of the semitransparent electrode 16 is arranged so as to avoid the light emitting (active) region.

Next, the operation characteristics of the EL element having the above structure will be described. First, in the operation as an EL element, a negative DC bias is applied to the back electrode 17 side and the semitransparent electrode 16 side. This means that the device operates in forward bias.

When the light emitting element is operated under such conditions, FIG. 2 shows a current-voltage characteristic curve diagram of the light emitting element.

In FIG. 2A, both the vertical axis (current) and the horizontal axis (voltage) are shown on a linear scale, and the applied voltage on the horizontal axis is shown at the interface between the semitransparent electrode 16 and the optoelectronic material layer 13 in FIG. The forward potential in the formed Schottky junction is the positive direction on the graph. This Figure 2 (a)
1 shows that the interface between the semitransparent electrode 16 and the optoelectronic material layer 13 has a strong rectifying characteristic due to the Schottky junction.
The external series resistance of the entire light emitting element estimated from extrapolation on the high current side when a forward voltage is applied is about 400Ω.

Next, in FIG. 2B, only the vertical axis (current) is shown in a logarithmic scale, and the horizontal axis (voltage) is shown in a linear scale with the forward potential in the Schottky junction as the positive direction on the graph. is there. The ideal factor n value of the Schottky junction can be obtained from the slope of the characteristic curve in this figure, but the n value of this light emitting element has an applied voltage dependency, and at 0.2 V or less, 1.8, It can be seen that the number is increased up to about 15 in the region higher than this. In general, a high n value that greatly exceeds 1 means that the interface state density is high and these are charged. That is, also from this point, the EL element emits light when a forward voltage is applied to the Schottky junction formed at the interface between the semitransparent electrode 16 and the optoelectronic material layer 13, and the reverse voltage is applied. It is considered that it does not emit light when applied.

FIG. 3 shows the emission intensity-current characteristic curve diagram of this EL element. Here, the vertical axis (emission intensity) and the horizontal axis (current) both use logarithmic scale display. According to FIG. 3, light emission starts when the forward current density is 30 mA / cm ² (forward voltage at this time is about 7.0 V), and thereafter, the emission intensity monotonically increases as the forward current increases. You can see it going. That is, the emission intensity I _EL and the forward current j can be expressed by the following relational expression (Equation 1).

[0070]

[Equation 1]

As described above, the emission intensity is 3.5 of the forward current.
The fact that it is proportional to the power means that the dependence of the emission intensity on the forward current is extremely steep, and it has not been observed in the conventional light-emitting device using microcrystalline Si as an active layer. The result. For example, porous S
In the EL device having the i layer as the active region, the emission intensity basically increases only in proportion to the forward current, as described in the related art.

FIG. 4 shows a light emission intensity-duty ratio characteristic curve diagram of the EL element of this embodiment at the time of pulse driving.

Here, logarithmic scale display is used for both the vertical axis (emission intensity) and the horizontal axis (duty ratio). Further, the voltage applied to the EL element had a pulse width of 20 μs and a voltage value of 32 V, and the duty ratio was changed from 0.25% to 100% (DC) by changing the frequency.

It can be seen from FIG. 4 that the light emission intensity decreases in proportion to the decrease in duty ratio. This result shows that the luminous efficiency is constant. That is,
It can be said that such an EL element is hardly affected by heat generation in the EL element. Further, it can be seen that it has a response speed of μs or less.

FIG. 5 shows both the photoluminescence (PL) and EL spectra (emission intensity-photon energy characteristic curve diagram) of this EL element.

The PL excitation method is as follows: Argon ion (A) with photon energy of 2.54 eV and power of 10 mW.
Laser light was directly irradiated to the optoelectronic material layer which will be the active layer, using an r ⁺ ) laser. The EL excitation condition is that the injection power into the optoelectronic material layer is 0.55 W to 1.10 W,
The emission active region was circular (3.1 × 10 ^-2 cm ² ).

According to FIG. 5, in PL, 2.10 eV
Main peak centered on (green) and 1.65 eV
The emission spectrum has a sub-peak centered on (red). On the other hand, EL has a broad emission spectrum with a central photon energy of 1.65 eV (red). Moreover, the peak position of the EL spectrum is slightly shifted to the low energy side as the injection power into the EL element is increased.

This result shows that the light emitting principle of this EL element is
It is not due to black body radiation due to heat generation. This is because in blackbody radiation, the peak of radiation shifts to the high-energy side as the temperature rises, but in the present embodiment, as described above, it increases rather with the increase in injection power (that is, temperature rise). It is shifting to the low energy side. Further, when the black body emits light having a peak at 1.65 eV, its temperature is estimated to be 3800 K, but in this result, such a high temperature is impossible.

It is considered that the operation principle of the light emitting device which exhibits the above results is explained as follows.

First, electrons (hot electrons) accelerated by a forward voltage are applied from the semitransparent electrode 16 on the light emitting element to the Schottky junction photoelectronic material layer 1.
Injected into 3. The injected electrons are the Si ultrafine particles 14
When reaching the main body, electron-hole pairs are excited (generated) by impact ionization. The quantum efficiency in this excitation process is about 1.0 when the injected electron energy is 4.0 eV.
It reaches to and rises as the energy rises.

Then, the injected electrons and the excited electron-hole pairs are once converted into Si ultrafine particles by the interface between the Si ultrafine particles 14 and the SiO ₂ film or transparent medium 15 formed on the surface thereof. 14 inside, and electron-hole pairs are generated within the Si ultrafine particles 14 under the applied voltage, that is, so to speak, multiplication (mutiplicati).
on) phenomenon and more excited electron-hole pairs are generated.

Due to the recombination phenomenon via the radiative recombination center corresponding to the excited electron-hole pairs that continue to be produced in a multiplying manner as described above, the dependence of the emission intensity on the forward current is extremely steep. It will exhibit a light emission phenomenon.

In addition, since the target Si ultrafine particles 14 are spherical with a particle size of nm level, the mean free path in which the electrons trapped in the ultrafine particles 14 and the excited electron-hole pairs move. It is also considered that the excited electron-hole pairs can be generated in a shorter and more effective manner by impact ionization.

On the other hand, in the EL device described in the second conventional example in the prior art, which uses porous Si as the active layer, basically, the excited electron-hole pair is generated by the injection of minority carriers in the junction (pn). The number of excited electron-hole pairs is proportional to the injection current, and as a result, the emission intensity is also proportional to the injection current. Also,
In this conventional example, although the porous Si has a fine structure of nm level, in reality, the porous Si has a linear shape. Therefore, when carriers drift in the porous Si. It is also considered that the relatively long mean free path adversely affects the generation efficiency of excited electron-hole pairs.

Further, as shown in FIG. 5, PL and EL
The reason why the emission spectra of the two do not match is considered as follows.

That is, in the generation of the excited electron-hole pair by the impact ionization and its multiplication in the EL process, the injected electron has much higher energy than the band gap (1.1 eV) of Si. In addition, the applied voltage is 26 to 32 V under the excitation condition of FIG. 5), and a transition to a higher energy side (so-called higher interband transition) is possible even in the conduction band. Therefore, not only the radiative recombination in the minimum bandwidth but also the radiative recombination with a higher energy difference will occur, and as a result, the width of the emission spectrum will be wider.

On the other hand, in PL, since the injected photon energy is relatively low at 2.54 eV, the proportion of occurrence of higher interband transition is low, and the width of the emission spectrum is considered to be narrower than that of EL. .

Further, in EL, impact ionization by injected electrons occurs in the Si ultrafine particles 14 main body near the surface of the Si ultrafine particles. Therefore, this excitation process is extremely sensitive to the interface state, but since there are many charged interface states at the interface, it is not possible to expect the same electron-hole pair excitation as in the bulk, and particularly high energy. It is considered that the excitation efficiency on the side is reduced.

On the other hand, in PL, the energy is 2.54e.
From the magnitude of the absorption coefficient when irradiating V excitation light,
It is considered that the excitation light with substantially the same intensity penetrates the entire ultrafine particles 14, and it is estimated that the electron-hole pairs are excited in bulk in almost the entire region including the central portion of each Si ultrafine particle 14, It is considered that the excitation efficiency on the high energy side does not decrease.

In the structure of such a light emitting device, the upper half of the optoelectronic material layer 13 is changed to a high concentration n − type, and the lower half of the optoelectronic material layer 13 and the entire substrate 11 are made to have a low concentration p −. When the mold is used, the contact between the optoelectronic material layer 13 and the metal semitransparent electrode 16 becomes ohmic, and a pn junction is formed in the center of the optoelectronic material layer 13. Here, if the impurity diffusion depth corresponding to the n-type is shorter than the original impurity diffusion depth corresponding to the p-type, a pn junction can be formed in the optoelectronic material layer 13.

In this structure, when a forward voltage (semitransparent electrode 16 side is negative with respect to the substrate 11 side) is applied, electrons inside the optoelectronic material layer 13 move from the high concentration n − type region to the low concentration p − type region. Minority carriers are mutually injected into the type region from the low concentration p − type region to the high concentration n − type region. The pn junction has an effect that the electron-hole pair can be efficiently generated, as compared with a configuration in which only electrons (minority carriers with respect to p-type Si) are injected through the Schottky junction. Then, when the deposition of the optoelectronic material layer 13 was completed, the arsenic (As) was introduced into the p-type Si substrate 11 by the ion implantation method. Ion implantation conditions at this time are acceleration energy of 100.
The keV was set at 5 × 10 ¹⁵ cm ^-2 .

Next, a method of controlling the emission wavelength (photon energy) in the visible light range in this light emitting device will be described.

First, as the first method, the particle size (size) of the Si ultrafine particles 14 is adjusted, and the bandgap width and the accompanying absorption edge emission energy are directly changed by the quantum confinement effect generated at this time. It is a thing. For example, Si simple ultrafine particles have a diameter of 4.0 nm and are red,
Green light can be emitted at 3.2 nm.

However, for blue color, a diameter of 2.8 nm corresponds, but in reality, it is quite difficult to control the size on the order of 2 nm in diameter, and as described above, the electron-hole pair of the electron-hole pair by the impact ionization is generated. The efficiency of the excitation decreases as the energy becomes higher. Furthermore, the surface atom ratio of ultrafine particles of the order of 2 nm reaches nearly 70%, and the influence of surface defects and the accompanying interface states cannot be ignored. Therefore, it can be said that the generation of blue color due to the quantum confinement effect is not easy to realize in the Si-only ultrafine particles 14.

Therefore, as a second method, in order to generate blue color by using the Si single-crystal ultrafine particles 14 as an active light emitting layer, the molecular arrangement of the surface oxide film at the interface between the Si ultrafine particles 14 and the surface oxide film is reconstructed. It is effective to form localized emission centers corresponding to the blue photon energy. More specifically, blue light can be emitted by forming the outermost surface of the Si ultrafine particles 14 into, for example, a chain siloxene structure.

In the case of a compound semiconductor, if the ultrafine particles of the compound semiconductor can be oxidized, the molecular arrangement of the oxide film of the compound semiconductor is reconstructed. Can be controlled.

Now, the principle structure of the photoelectric conversion element using the optoelectronic material used in the color sensor of the present invention will be described below.

In such a color sensor, as in the case of the light emitting element, among the group IV semiconductors, the ultrafine particles of Si whose surface is coated with its own thermal oxide film are conductive. Photoelectric conversion element having a photoelectron material layer dispersed in a homogeneous transparent medium whose permittivity or permittivity is controllable as a light receiving (active) region, and receiving light (active) on such optoelectronic material layer A photoconductive photoelectric conversion element used as a region is preferably used.

Therefore, the photovoltaic type photoelectric conversion element will be described below. In some cases, the oxide film of ultrafine particles may be omitted.

FIG. 6 shows a cross-sectional structure of a photoelectric conversion element using a photoelectronic material. In FIG. 6, reference numeral 61 denotes a substrate, and as an example, p-type Si having a plane orientation (100), conductivity of boron-doped p-type, and specific resistance of 10 Ω · cm.
A substrate was used. On the upper surface of the p-type Si substrate 61, an isolation insulating film 62, which is an example of a SiO ₂ film, is formed with a thickness of 100 nm. In this isolation insulating film 62, a portion which should be a light receiving (active) region of the photoelectric conversion element,
An opening 62a having a diameter of about 10 mm is formed on the substrate 61.
The surface is exposed.

Then, the optoelectronic material layer 63 is deposited so as to cover at least the opening 62a. This optoelectronic material layer 63 is made of the Si ultrafine particles 6 as described above.
4 are dispersed in the transparent medium 65. The structure of the optoelectronic material layer 63 is the same as that of the optoelectronic material layer 13 described above.
It has the same configuration as. That is, the Si ultrafine particles 64 are
The shape is almost spherical, the crystallinity has the same crystal structure as bulk Si, and the conductivity is p-type doped with boron in a low concentration, and the particle size is about 3 to 10 nm. Has been adjusted. Further, the surface of the Si ultrafine particles 64 is covered with a SiO ₂ film (not shown) having a thickness of 1 to 5 nm. Further, the transparent medium 65 is a homogeneous thin film having a high transmittance in the visible light region and a controllable conductivity or permittivity. Here, a SnO ₂ thin film was used as an example.

Although Si is used as the material of the ultrafine particles forming the optoelectronic material layer here, other group IV semiconductors such as Ge or a mixed crystal thereof can be preferably used.
A II-V group or II-VI group compound semiconductor may be used. Although the SnO ₂ thin film was used as the homogeneous transparent medium, another conductive thin film or dielectric thin film having a specific resistance equal to or higher than the specific resistance of the ultrafine particles to be dispersed may be used.

Further, as an example, a semi-transparent electrode 66 having a thickness of 10 nm and made of Pt is in contact with the upper surface of the optoelectronic material layer 63, and the optoelectronic material layer 63 including the transparent medium 15 whose conductivity is controlled is electrically connected to the optoelectronic material layer 63. Specifically, a so-called Schottky junction is formed. A back electrode 67 made of Pt, for example, is provided on the lower surface of the substrate 61 to electrically form an ohmic contact with the substrate 61.

The electrodes 66 and 67 are not limited to Pt.
It is also possible to mainly form any of aluminum, gold, silver, tungsten, molybdenum, tantalum, and the like.

Then, the semitransparent electrode 66 and the back electrode 67
Is connected to a power source by a wire lead wire or the like via a conductive paste 68 or the like as necessary. Here, it is preferable that the conductive paste 68, which is a power source connection position on the semitransparent electrode 66 side, is arranged so as to avoid the light receiving (active) region.

Next, the operation principle of the photovoltaic type light receiving element having the above structure will be described.

First, in the operation as a light receiving element, a positive DC bias is applied to the back electrode 67 side to the semitransparent electrode 66 side. In the present device structure, as shown in FIG. 2A in the first embodiment, strong rectification characteristics due to the Schottky junction at the interface between the semitransparent electrode 66 and the optoelectronic material layer 63 are shown. Is about several to several tens of volts.

In this state, when the photoelectron material layer 63 is irradiated with light having a photon energy larger than the band gap energy of the Si ultrafine particles 64, carriers of electron-hole pairs are generated in the Si ultrafine particles 64 by the photoelectric effect. The generated electrons reach the semitransparent electrode 66. As a result, a photoelectromotive force is generated at the Schottky junction formed by the semitransparent electrode 66 and the optoelectronic material layer 63. By detecting this photoelectromotive force, a light receiving function is exhibited.

In the structure of the light receiving element using the optoelectronic material of the present embodiment, the upper half of the optoelectronic material layer 63 is changed to a high-concentration n − type, and the lower half of the optoelectronic material layer 63 and the substrate 61. If the whole is made into a low concentration p-type,
The contact between the optoelectronic material layer 63 and the semitransparent metal electrode 66 becomes ohmic, and a pn junction is formed in the center of the optoelectronic material layer 63. Here, if the impurity diffusion depth corresponding to the n-type is shorter than the original diffusion depth corresponding to the p-type, a pn junction can be formed in the optoelectronic material layer 63.

In this structure, light having a photon energy larger than the bandgap energy of the Si ultrafine particles 64 is applied to the optoelectronic material layer 63 in the state where a reverse voltage (the semitransparent electrode 66 side is positive with respect to the substrate 61 side) is applied. Is irradiated, the carriers of electron-hole pairs are generated in the Si ultrafine particles 64 due to the photoelectric effect. Then, inside the optoelectronic material layer 63, electrons go to the high-concentration n-type region and holes go to the low-concentration p-type region.
Minority carriers are mutually accelerated to the mold region, and a photoelectromotive force is generated at the pn junction. The pn junction has an effect that the dark current is smaller than that of the Schottky junction structure.

By the way, since the bandgap energy of Si is 1.1 eV (the limit light receiving wavelength is 1100 nm), bulk Si has a light receiving sensitivity in almost the entire visible light region.

On the other hand, a method of controlling the light receiving wavelength region in the photoelectric conversion element will be described.

First, as a first method, the particle size (size) of the Si ultrafine particles 64 is adjusted, and the bandgap energy is directly changed by the quantum confinement effect generated at this time. For example, with Si simple ultrafine particles,
Diameter 4.0nm red, 3.2nm green 2.8nm
The blue color becomes the absorption edge region. Therefore, if the diameter of the Si simple substance ultrafine particles is 3 nm or less, a light receiving element having sensitivity only in the blue region can be realized without using a color filter.

However, in reality, it is quite difficult to control the size on the order of 2 nm in diameter, and the surface atom ratio of the ultrafine particles on the order of 2 nm in diameter reaches close to 70%. The effect of is not negligible.

Therefore, as a second method, the molecular arrangement of the surface oxide film at the interface between the Si ultrafine particles 64 and the surface oxide film is reconstructed to form, for example, a localized emission center corresponding to blue photon energy. It is valid. More specifically, by forming the outermost surface of the Si ultrafine particles 64 with, for example, a chain siloxene structure, the light receiving sensitivity in the blue region is improved.

In the case of a compound semiconductor, if the ultrafine particles of the compound semiconductor can be oxidized, the molecular arrangement of the oxide film of the compound semiconductor is reconfigured, and if it cannot be oxidized, the molecular arrangement of a dielectric film of a different type is reconfigured. Can be controlled.

By using the photoelectric conversion element using the optoelectronic material having the above-described light receiving characteristics, it is possible to construct an ultraviolet sensor or a blue sensor made of a group IV semiconductor without using a filter or the like.

Furthermore, as is clear from the above description,
The photoelectric conversion element using the optoelectronic material of the present embodiment naturally has a function as a light emitting element. That is, when a negative DC bias is applied to the semitransparent electrode 66 side with respect to the back surface electrode 67 side, electrons are injected into the active layer 63 to excite electron-hole pairs. The excited electron-hole pair emits light according to the band gap energy of the ultrafine particles in the recombination process. Therefore, a photoelectric conversion element capable of receiving and emitting light can be obtained.

Next, the principle structure of the photoconductive photoelectric conversion element will be described in detail below with reference to FIG.

FIG. 7 shows a sectional structure of a photoconductive type photoelectric conversion element using a photoelectronic material. In FIG. 7, 71
Is a substrate, and as an example, a glass substrate widely used in Si-LSI process was used. This glass substrate 71
A Pt lower electrode 72 as an example is formed on the upper surface of the. A photoelectron material layer 73 is deposited on the upper surface of the lower electrode 72. As described above, the optoelectronic material layer 73 is composed of Si ultrafine particles 74 dispersed in the transparent medium 75. The Si ultrafine particles 74 are substantially spherical in shape, have the same crystallinity as the crystallinity of bulk Si, and have p-type conductivity in which boron is doped at a low concentration, Diameter is 3 to 10
It is adjusted to about nm. The transparent medium 75 is a homogeneous thin film having a high transmittance in the visible light region and a controllable electric conductivity or dielectric constant. Here, as an example,
A SnO ₂ thin film was used. This SnO ₂ thin film has a visible light transmittance of 80% or more, and further it is possible to control the electric conductivity or the dielectric constant by adjusting the manufacturing conditions (substrate temperature, oxygen partial pressure, etc.), In the present embodiment, since the photoconductive type light receiving element is used, the specific resistance is set to be about the same as the specific resistance of the Si ultrafine particles.

Although Si is used as the material of the ultrafine particles forming the optoelectronic material layer here, as described in the first and second embodiments, other materials such as Ge or a mixed crystal thereof may be used.
V group semiconductors can be preferably used, and III-V group and I group semiconductors can be used.
A group I-VI compound semiconductor may be used. Although the SnO ₂ thin film was used as the homogeneous transparent medium, another conductive thin film or dielectric thin film having a specific resistance equal to or higher than the specific resistance of the ultrafine particles to be dispersed may be used.

Furthermore, a semitransparent electrode 76 having a thickness of 10 nm and made of Pt is in contact with the upper surface of the optoelectronic material layer 73.

The electrodes 72 and 76 are not limited to Pt.
It is also possible to mainly form any of aluminum, gold, silver, tungsten, molybdenum, tantalum, and the like.

Then, the semitransparent electrode 76 and the lower electrode 72
Is connected to the resistance meter by a wire lead wire or the like through a conductive paste or the like as necessary.

Next, the operation principle of the photoconductive type light receiving element having the above-mentioned structure will be described.

The operation as a light receiving element using the optoelectronic material of the present embodiment is such that when the optoelectronic material layer 73 is irradiated with light, optical energy is absorbed in the Si ultrafine particles 74 of the optoelectronic material layer 73, and Electrons in the electron band or donor level are excited in the conduction band. These become free electrons, which are accelerated by an external electric field and reach the electrodes. As a result, the internal resistance of the optoelectronic material layer 73 decreases. A light receiving function is exhibited by detecting the change in the internal resistance.

Regarding the method of controlling the light receiving wavelength region in the photoelectric conversion element using such an optoelectronic material,
As described in the second embodiment, the particle size (size) of the main body of the Si ultrafine particles 74 is adjusted, and the bandgap energy is directly changed by the quantum confinement effect generated at this time. Of its oxide film,
If oxidation is not possible, there is a method of controlling by reconstructing the molecular arrangement of another type of dielectric film.

Even if the photoconductive type photoelectric conversion element having the above light receiving characteristics is used, it is possible to construct an ultraviolet sensor or a blue sensor made of a group IV semiconductor without using a filter or the like.

Here, as a more specific example of the light receiving sensor, the principle configuration of a color sensor using the optoelectronic material of the present invention will be described with reference to FIGS. 8 and 9.

Here, a photoconductive material of a group IV semiconductor, in which ultrafine particles of Si are dispersed in a homogeneous transparent medium whose conductivity or permittivity is controllable, is used as a light receiving (active) region. A color sensor in which photoelectric conversion elements are typically stacked will be described.

FIG. 8 shows a sectional structure of a color sensor using such an optoelectronic material. In FIG. 8, 81, 8
Reference numerals 2 and 83 are first, second and third photoelectric conversion layers, respectively. Each photoelectric conversion layer has the same structure as the photoconductive type light receiving element described above, and is arranged in contact with the optoelectronic material layer 84 in which the Si ultrafine particles 85 are dispersed in the transparent medium 86, and above and below it. , As an example, the thickness is 10 nm and the material is P
It is composed of t semi-transparent electrodes 87. The upper and lower semitransparent electrodes 87 are connected to a resistance meter by a wire lead wire or the like via a conductive paste or the like as necessary.

Here, the Si ultrafine particles 85 of the optoelectronic material layer 84 have a substantially spherical shape, have the same crystallinity as bulk Si, and have a low concentration of boron doped in conductivity. P-type. Further, the transparent medium 86 is a homogeneous thin film having a high transmittance in the visible light region and a controllable conductivity or permittivity. Here, as an example,
Sn having a resistivity similar to that of ultrafine Si particles
An O ₂ thin film was used. Then, Si in the optoelectronic material layer 84
The higher the filling rate of the ultrafine particles 85, the larger the change in the internal resistance of the optoelectronic material layer 84 as a whole, that is, the larger the light receiving sensitivity. Therefore, it is preferable to set it to 50% or more.

Although Si was used as the material of the ultrafine particles constituting the optoelectronic material layer here, as described above,
Besides, Group IV semiconductors such as Ge or mixed crystals thereof can be preferably used, and Group III-V or Group II-VI compound semiconductors may be used. And, as a homogeneous transparent medium, Sn
Although the O ₂ thin film is used, other conductive thin film or dielectric thin film having a specific resistance equal to or higher than the specific resistance of the ultrafine particles to be dispersed may be used. Further, the semitransparent electrode 87 can be formed mainly of any one of aluminum, gold, silver, tungsten, molybdenum, tantalum, etc. other than Pt.

Each photoelectric conversion layer 81, 8 having the above structure
2, 83 are made of S, which has a high visible light transmittance, as an example.
_They are electrically insulated from each other by the isolation insulating film 88 which is an iO ₂ film.

Here, as the isolation insulating film, SiO _{2 is used.}
Although a film is used, an insulator having a high visible light transmittance, for example, Al
_{A 2} O ₃ film or the like may be used.

Next, the operation principle of light reception in the color sensor having the above structure will be described.

First, in the operation of each photoelectric conversion layer using the optoelectronic material of the present embodiment, when the optoelectronic material layer 84 is irradiated with light, carriers are generated in the Si ultrafine particles 85 of the optoelectronic material layer 84. , Is accelerated by an external electric field and reaches the electrode. As a result, the internal resistance of the optoelectronic material layer 84 decreases. A light receiving function is exhibited by detecting the change in the internal resistance.

In the light receiving wavelength region of each photoelectric conversion layer exhibiting the above light receiving function, as described above, by making the shape of Si into ultrafine particles having a particle size on the order of several nm, the Eg increasing phenomenon due to the quantum confinement effect. Can be controlled by using. That is, by adjusting the average particle size or surface atomic arrangement of the Si ultrafine particles contained in each photoelectric conversion layer, it becomes possible to impart different light receiving characteristics to each photoelectric conversion layer.

In addition, the first, second and third photoelectric conversion layers 81 and 8
When the sizes of the Si ultrafine particles contained in Nos. 2 and 83 are increased in this order, Eg increases as the size of the ultrafine particles decreases, so that the optical gap increases in layers closer to the light receiving surface side. This state is shown in FIG. More specifically, the first,
The diameters of the ultrafine particles of the 2 and 3 photoelectric conversion layers are 3.0 nm, 3.5 nm, and 4.0 nm, respectively, as an example, and the optical gaps of the photoelectric conversion layers are in the blue, green, and red regions, respectively. I did it. As a result, the red (R) light is not absorbed by the first and second photoelectric conversion layers and is transmitted to the third photoelectric conversion layer.
It is absorbed by the photoelectric conversion layer. Similarly, the green (G) light passes through the first photoelectric conversion layer and is absorbed by the second photoelectric conversion layer (and the third photoelectric conversion layer depending on the thickness), and the blue (B) light is mainly absorbed by the first photoelectric conversion layer. It is absorbed by one photoelectric conversion layer. Therefore, from the difference in the received light intensity in each photoelectric conversion layer, R, G, B
It is possible to obtain the respective intensities, and by appropriately performing signal processing on these three primary colors, it is possible to perform color identification including the intermediate colors.

In such a color sensor, a photoconductive type light receiving element is used as the photoelectric conversion layer, but of course, it may be composed of a photovoltaic type light receiving element. Is advantageous in terms of linearity, high-speed response characteristics, low noise, and the like.

(Example A of Optoelectronic Material) The principle structure of another optoelectronic material of the present invention that can be used in a color sensor will be described in detail below with reference to FIGS. 10 and 11.

Here, also in the group IV semiconductors,
Typically, the photoluminescence (P) is formed by using an ultrafine particle dispersion layer in which ultrafine particles of Si whose surface is coated with its own thermal oxide film are dispersed in a homogeneous transparent medium.
L) The light emitting member will be described as a representative, and the oxide film of ultrafine particles may be omitted in some cases.

FIG. 10 shows a sectional structure of this optoelectronic material. In FIG. 10A, 101 is a substrate, and as an example, plane orientation (100) and conductivity of boron-doped p
A p-type Si substrate having a − type and a specific resistance of 10 Ω · cm was used. On the upper surface of the p-type Si substrate 61, a transparent material layer 102 having a low refractive index and an ultrafine particle dispersion layer 103 having a high refractive index are alternately laminated at a predetermined cycle to form a periodic structure. ing. Here, the transparent material layer 102 is
It is a homogeneous thin film having a high transmittance in the visible light region and a controllable electric conductivity or dielectric constant, and an ITO thin film was used as an example. This ITO thin film has a visible light transmittance of 90% or more, and the conductivity and the dielectric constant can be controlled by adjusting the manufacturing conditions (substrate temperature, oxygen partial pressure, etc.). For example, by adjusting the addition rate of SnO ₂ when forming an ITO thin film by the vapor deposition method within the range of several to several tens wt%, the specific resistance is 10 ⁻⁴ to 10 ⁻² Ω.
・ It can be controlled in the range of about cm. Also, the dielectric constant can be controlled within the range of about 4 to 5.

Here, as a uniform transparent material layer, I
Although a TO thin film was used, according to the design of the periodic structure described later,
It is preferable to use a homogeneous thin film having a desired dielectric constant as the low refractive index layer, and another conductive thin film such as SnO ₂ ,
A TiO ₂ , InO ₂ thin film or the like may be used, and SiO ₂ , A
It is also possible to use a dielectric thin film such as l ₂ O ₃ . Further, this optoelectronic material can be used as the optoelectronic material layer of the EL element or the light receiving element described above. In this case, it is preferable that the transparent material layer has high conductivity.

Further, the ultrafine particle dispersion layer 103 is shown in FIG.
As shown in (b), Si ultrafine particles 105 are dispersed in a transparent medium 104. The structure of the ultrafine particle dispersion layer 103 is similar to that of the optoelectronic material layer 13 described in the first embodiment. That is, Si ultrafine particles 10
No. 5 has a substantially spherical shape, has the same crystallinity as that of bulk Si in crystallinity, and has a p-type conductivity in which boron is doped in a low concentration, and has a grain size of 3 to 3. It is adjusted to about 10 nm. Further, the Si ultrafine particles 105
Has a surface covered with a SiO ₂ film (not shown) having a thickness of 1 to 5 nm. Further, the transparent medium 104 is a homogeneous thin film having a high transmittance in the visible light region and a controllable conductivity and permittivity. Here, as an example, Sn is used.
An O ₂ thin film was used.

Although Si is used as the material of the ultrafine particles constituting the ultrafine particle dispersion layer here, other group IV semiconductors such as Ge or a mixed crystal thereof can be preferably used.
A group III-V or group II-VI compound semiconductor may be used. Although the SnO ₂ thin film was used as a homogeneous transparent medium, it is preferable to use a homogeneous thin film having a desired dielectric constant as the high refractive index layer according to the design of the periodic structure described later. A thin film may be used. Further, this optoelectronic material can be used as the optoelectronic material layer of the EL element or the light receiving element described above. In this case, the transparent medium of the ultrafine particle dispersion layer has the same resistivity as the ultrafine particles to be dispersed. It is desirable to have a specific resistance of a degree or more.

Next, a method of designing a periodic structure in such an optoelectronic material will be described.

In the case where this optoelectronic material exhibits a light emission phenomenon as described later, when the center wavelength of the desired emitted light is λ, the optical film thickness of one cycle of the lamination of the transparent material layer 102 and the ultrafine particle dispersion layer 103 The layers are alternately laminated so that (refractive index × film thickness) is λ / 2. As an example of the design of periodic structure, λ
Is 600 nm, and the optical film thickness of each layer is 150 nm (λ /
4). More specifically, since the typical refractive index of the ITO thin film is 2.1, the film thickness of the transparent material layer 102 which is a low refractive index layer was set to 71 nm.

Regarding the ultrafine particle dispersion layer 103,
It was designed based on the average effective medium theory. That is, it is assumed that the ultrafine particle dispersion layer is formed by dispersing spherical ultrafine particles having a dielectric constant ε at a filling rate f in a transparent medium having a dielectric constant ε _m .
When the particle size of the ultrafine particles is sufficiently smaller than the wavelength, the average dielectric constant ε _av of the ultrafine particle dispersion layer is represented by the following relational expression (Equation 2).

[0150]

[Equation 2]

Here, the typical dielectric constant of the SnO ₂ thin film is 4.8, and the value of bulk Si (11.9) is approximately used as the dielectric constant of the ultrafine Si particles. Further, the filling rate f is 5
When it is 0%, the average dielectric constant of the ultrafine particle dispersion layer is 7.6 according to the above equation. Since the refractive index can be approximated to the 1/2 power of the dielectric constant, the average refractive index of the ultrafine particle dispersion layer is 2.8.
Is obtained. Therefore, the film thickness of the ultrafine particle dispersion layer which is a high refractive index layer is set to 54 nm.

Here, the optical film thickness of each layer is λ / 4.
However, considering absorption in the ultrafine particle dispersion layer 103,
1 of lamination of transparent material layer 102 and ultrafine particle dispersion layer 103
The optical film thickness of the period is set to λ / 2, and then the ultrafine particle dispersion layer 1
The optical film thickness of 03 may be smaller than λ / 4. Thereby, the efficiency of extracting the emitted light of the optoelectronic material can be improved.

Next, the physical properties of the optoelectronic material having the above-described structure will be described on behalf of the operation principle of light emission.

First, when light having a photon energy equal to or higher than the band gap energy (Eg) of ultrafine particles is irradiated, electron-hole pairs are generated in the Si ultrafine particles 105 in the ultrafine particle dispersion layer 103. The generated electron-hole pair emits light according to the Eg of the ultrafine particles due to the recombination phenomenon via the corresponding radiative recombination center.

Since the group IV semiconductor is an indirect transition type by nature, the probability of radiative recombination is extremely low, but if the shape is made into ultrafine particles having a particle size of several nanometers, the probability increases, and strong luminescence may be exhibited. It will be possible. Here, the emission wavelength control method utilizes the phenomenon of increasing Eg due to the quantum confinement effect. That is, the particle size of the Si ultrafine particles,
It is possible to obtain the required emission wavelength by adjusting the structure of the surface atomic arrangement.

However, the emission spectrum of the ultrafine particles alone has a wide spectrum width as shown in FIG. 11 (a). As shown in FIG. 5, the ultrafine Si particles have a spectral width of about 0.3 eV.

On the other hand, according to the design of the periodic structure described above, when the transparent material layer 102 and the ultrafine particle dispersion layer 103 are alternately laminated so that the optical film thickness of one cycle is λ / 2, the transparent material layer and the ultrafine particle layer are superposed. Due to the difference in the refractive index of the fine particle dispersion layer, multiple interference occurred at the interface of each layer, and only the emission intensity in the wavelength region centered on λ could be enhanced. This state is shown in FIG.
It shows in (b). This spectrum width becomes narrower as the number of layers of the periodic structure increases, so the number of layers may be adjusted according to the required spectrum width.

Further, the particle diameter or surface atomic arrangement of the Si ultrafine particles is adjusted so that the central wavelength of the original light emitted from the Si ultrafine particles coincides with the central wavelength enhanced by the periodic structure. By adjusting the film thickness of each layer according to the design, the effect of enhancing the intensity in the desired wavelength region in the continuous spectrum originally generated by the ultrafine particles can be enhanced.

The light emitting characteristics of the optoelectronic material have been mainly described above. Of course, the optoelectronic material having such characteristics can be used as the optoelectronic material layer of the color sensor.

In this case, it is possible to enhance the received light intensity in a desired narrow band wavelength region of the continuous spectrum that the ultrafine particles originally receive.

(Example B of Optoelectronic Material) The principle structure of another optoelectronic material that can be used in the above-described color sensor will be described in detail below with reference to FIG.

Also in the IV group semiconductor, the active layer in which the ultrafine particles of Si whose surface is coated with its own thermal oxide film is dispersed in the homogeneous transparent medium is used as a light emitting (active) region. Further, the optoelectronic material as the photoluminescence (PL) light emitting member will be described, and in some cases, the oxide film of ultrafine particles may be omitted.

FIG. 12 shows the sectional structure of this optoelectronic material. In FIG. 12, 121 is a substrate, and as an example, a glass substrate frequently used in the Si-LSI process is used. On the upper surface of the glass substrate 121, as an example, a metal thin film layer 122 having a thickness of 100 nm and made of aluminum (Al) is provided.

A material having a high reflectance in the visible light region may be used for the metal thin film layer 122, and in addition to Al, any of Pt, aluminum, gold, silver, tungsten, molybdenum, tantalum, etc. is mainly used. It is also possible to form it.

A multi-layer film layer 123 is formed on the upper surface of the metal thin film layer 122. The multilayer film layer 123 has at least two types of layers having different refractive indexes alternately laminated to form a periodic structure. As an example, a transparent medium layer made of an ITO thin film and a SiO ₂ thin film made of a SnO ₂ thin film. It is composed of an optoelectronic material in which ultrafine particle dispersion layers dispersed therein are alternately laminated.

The periodic structure of the multilayer film 123 is
The optical film thickness (refractive index × film thickness) of the period was set to λ / 2 (λ: central wavelength of emitted light). That is, as an example, λ is 600 nm, the thickness of the transparent medium layer is 71 nm,
The multilayer film layer 123 was formed by alternately stacking the ultrafine particle dispersion layers with a film thickness of 54 nm.

Although the optoelectronic material is used here as the multilayer film layer 123, a dielectric multilayer film or the like conventionally used as a multilayer reflective film in the visible light region may be used.

Next, the active layer 124 is formed on the upper surface of the multilayer film 123. The active layer 124 has the same structure as that of the ultrafine particle dispersion layer 103 described above, and is made of Si.
The ultrafine particles 125 are dispersed in a transparent medium 126. The Si ultrafine particles 124 have a substantially spherical shape and have the same crystallinity as bulk Si.
Moreover, the conductivity is p-type in which boron is doped in a low concentration, and the particle size is adjusted to about 3 to 10 nm. Further, the surface of the Si ultrafine particles 124 is covered with a SiO ₂ film (not shown) having a thickness of 1 to 5 nm.
In addition, the transparent medium 125 is a homogeneous thin film having a high transmittance in the visible light region and a controllable electrical conductivity and dielectric constant. Here, a SnO ₂ thin film was used as an example.

Further, the optical film thickness (refractive index × film thickness) of the active layer 124 is an integral multiple of λ. Here, as an example, λ is 600 nm and the optical film thickness of the active layer 124 is 2 nm.
It was set to λ. More specifically, the refractive index of the active layer 124 is
As an example, the filling rate is set to 50 as determined in the fifth embodiment.
When it is set to%, it becomes 2.8. Therefore, the active layer 12
The film thickness of 4 was 429 nm.

Although Si is used as the material of the ultrafine particles forming the active layer here, other group IV semiconductors such as Ge or a mixed crystal thereof can be preferably used.
A group V or group II-VI compound semiconductor may be used. Although the SnO ₂ thin film was used as a homogeneous transparent medium, it is preferable to use a homogeneous thin film having a desired dielectric constant according to the design of the periodic structure described in the fourth embodiment. A thin film may be used.

Further, this optoelectronic material is based on the above-mentioned EL.
It can be used as an optoelectronic material layer of an element or a light receiving element. In this case, it is desirable that the transparent medium of the active layer has a specific resistance equal to or higher than the specific resistance of the ultrafine particles to be dispersed.

Further, on the upper surface of the active layer 124, as an example, the partial reflection film layer 1 having a thickness of 10 nm and made of Pt is used.
27 are provided.

A material having an appropriate reflectance in the visible light region may be used for the partial reflection film layer 127, and in addition to Pt, any of Al, gold, silver, tungsten, molybdenum, tantalum, etc. is the main constituent. It is also possible to form it.
Further, it is also possible to use a dielectric multilayer film which is conventionally used as a partial reflection film in the visible light region.

Next, in the optoelectronic material having the above structure,
When the active layer 34 containing ultrafine particles is irradiated with light having a photon energy higher than the bandgap energy (Eg) of the ultrafine particles, light emission having a wide spectrum width as shown in FIG. 11A is exhibited.

Therefore, as described above, the multilayer film layers 123 are alternately laminated so that the optical film thickness of one cycle is λ / 2 to form a periodic structure. When formed so as to be an integral multiple of λ, the active layer 124 forms a resonator structure sandwiched between the multilayer film layer 123 and the partial reflection film layer 127, so that as shown in FIG. It is possible to enhance only the emission intensity in the wavelength region of

Furthermore, since an optoelectronic material is used for the multilayer film layer 123, the Si ultrafine particles in the multilayer film layer 123 also emit light, and the emission intensity is further enhanced.

Further, the particle diameter or surface atomic arrangement of the Si ultrafine particles is adjusted so that the central wavelength of the original light emission of the Si ultrafine particles coincides with the central wavelength enhanced by the periodic structure. By adjusting the film thickness of each layer according to the design, the effect of enhancing the intensity in the desired wavelength region in the continuous spectrum originally generated by the ultrafine particles can be enhanced.

The light emitting characteristics of the optoelectronic material have been mainly described above. Of course, the optoelectronic material having such characteristics can be used as the optoelectronic material layer of the color sensor.

In this case, it is possible to enhance the received light intensity in a desired narrow band wavelength region of the continuous spectrum that the ultrafine particles originally receive.

(Manufacturing Example of Optoelectronic Material) The preferred manufacturing method of the optoelectronic material of the present invention described above will be described below with reference to FIG.
Will be described in detail.

Here, a method of manufacturing an optoelectronic material composed of a transparent conductor thin film in which Si ultrafine particles are dispersed will be described. Si ultrafine particles and a transparent conductor material are simultaneously deposited on the same substrate to obtain a transparent material. There is a step of dispersing Si ultra-fine particles in the conductor thin film, and the Si ultra-fine particles are produced by using laser ablation in a rare gas (Ar, He, etc.) atmosphere, adhered and deposited on the substrate, and are transparent conductor thin films. Is formed on the same substrate so as to disperse Si ultrafine particles therein through an evaporation step, preferably laser ablation in an oxidizing gas atmosphere.

The laser ablation method is a high energy density (pulse energy: 1.0 J / cm ²
Degree or more. ) Is irradiated to the target material to cause melting and desorption of the surface of the irradiated target material. Here, the desorbed substances at a pulse energy density of about 1.0 J / cm ² are atoms, molecules, and clusters (composed of several to several tens of atoms) which are mainly ions and neutral particles. Is. It is known that the kinetic energy is several tens eV for ions and several eV for neutral particles, but the distribution of kinetic energy at this time corresponds to tens of thousands of degrees Celsius or more when converted into temperature. So
It can be said that an extreme non-thermal equilibrium state is emerging.

Specifically, in FIG. 13, by performing laser ablation of a Si target and a transparent conductor target at the same time, Si is uniformly formed in a transparent conductor thin film.
1 is a conceptual diagram of an optoelectronic material manufacturing apparatus for forming an optoelectronic material thin film in which ultrafine particles are dispersed.

In FIG. 13, the all-metal first reaction chamber 1301 is first evacuated to a ultimate vacuum of 1.0 × 10 ^-9 Torr by a high vacuum evacuation system mainly composed of a turbo molecular pump, and then the mass flow controller 1302 is activated. Ar gas is introduced through the rare gas introduction line 1303 via the via.
Here, by interlocking with the operation of the gas exhaust system 1304 mainly composed of the dry rotary pump or the high-pressure turbo molecular pump, the rare gas pressure in the first reaction chamber 1301 is controlled within the range of 0.01 to 1.0 Torr. Set to one pressure value.

Then, in this state, the first pulse laser light source 1 is applied to the surface of the Si target 1306 arranged in the first target holder 1305 having the rotation mechanism.
Laser light is emitted from 307. Then, a laser ablation phenomenon occurs on the surface of the Si target 1306, and Si ions or neutral particles (atoms, clusters) are desorbed, and initially 50 eV of ions and 5 of neutral particles.
With kinetic energy of the order of eV, it is emitted mainly in the target normal direction. When the desorbed substance collides with the rare gas atom, the flight direction becomes disordered, and kinetic energy is dissipated in the atmosphere to promote association and condensation in the air. As a result, particle diameters of several nm to several tens of n
m to grow into ultrafine particles.

In the all-metal second reaction chamber 1308, the ultimate vacuum of 1.0 × 10 ⁻⁹ T is obtained by the high vacuum exhaust system.
After exhausting to orr, mass flow controller 130
Oxygen-containing gas is introduced from the oxidizing gas introduction line 1310 via the line 9. It is preferable that oxygen is mixed in He gas in the order of several%. Here, by interlocking with the operation of the gas exhaust system 1311 mainly composed of a dry rotary pump or a high-pressure turbo molecular pump, the gas pressure in the second reaction chamber 1308 is
It is set to one pressure value in the range of 0.01 to 1.0 Torr. Then, in this state, the second pulse laser light source 13 is applied to the surface of the SnO ₂ target 1313 arranged in the second target holder 1312 having the rotation mechanism.
When laser light from 14 is irradiated, a laser ablation phenomenon occurs on the surface of the SnO ₂ target 1313, and S
nO ₂ ions or neutral particles (atoms, clusters)
Desorbed, initially 50 eV for ions and 5 eV for neutral particles
With the kinetic energy of the order of, the size of atoms and clusters are mainly maintained in the direction of the target normal, and they are ejected. At this time, the oxygen gas atmosphere is maintained so that the oxygen composition of SnO ₂ is not reduced and the stoichiometric composition is maintained.

On the other hand, a deposition substrate 1316 is arranged in the vacuum reaction chamber 1315, and the ultimate vacuum of 1.0 × 10 ⁻⁶ To is obtained by a high vacuum exhaust system 1317 mainly composed of a turbo molecular pump.
It is exhausted to about rr. This vacuum reaction chamber 1315
By the pressure difference between the first reaction chamber 1301 and the first reaction chamber 1301.
The Si ultra-fine particles generated in 01 are the first nozzle 131.
8 to be injected into the vacuum reaction chamber 1315, and the substrate 1
316.

Similarly, due to the pressure difference between the vacuum reaction chamber 1315 and the second reaction chamber 1308, the SnO ₂ clusters generated in the second reaction chamber 1308 pass through the second nozzle 1319 and are transferred in the vacuum reaction chamber 1315. Jetted onto the substrate 1316
Deposited as a thin film on.

Therefore, by performing the laser ablation of Si and SnO ₂ at the same time, a uniform SnO ₂ in which Si ultrafine particles are dispersed is deposited on the deposition substrate 1316.
(Transparent conductor) It becomes possible to form a thin film. Further, in the present embodiment, since active oxygen for forming the transparent conductor thin film exists only in the second reaction chamber 1308, the Si ultrafine particles which are very easily oxidized are exposed to the active oxygen atmosphere. Instead, it can be dispersed in the transparent conductor thin film.

The difference between the case where Ar is used as the atmosphere rare gas and the case where He is used is 0. It is necessary to set the pressure to 1 to 0.2 times.

In the above description, the Si ultrafine particles are replaced by S.
The method for producing an optoelectronic material dispersed in an nO ₂ thin film has been described, but as the material for the ultrafine particles, it is of course possible to use a simple substance or a mixed crystal of other types and composition ratios. As the transparent medium material to be dispersed,
In addition to the transparent conductor thin film, a dielectric thin film such as SiO ₂ can be used.

In some cases, the ultrafine Si particles may be oxidized in an oxygen atmosphere or may be oxidized by thermal oxidation.

In the above description, the Si ultrafine particles generated in the first reaction chamber were directly deposited on the substrate through the first nozzle, but in this case, the particle size distribution of the ultrafine particles is widened. . Therefore, a method of controlling the particle size of the Si ultrafine particles in the manufacturing process of the optoelectronic material of the present invention will be further described with reference to FIG.

FIG. 14 is a schematic view of a particle size control device for controlling the particle size by using mass separation when depositing ultrafine particles by the laser ablation method.

In FIG. 14, as described above, in the reaction chamber of the rare gas atmosphere, the target 14 placed therein is placed.
When the pulsed laser light is applied to the surface of No. 1, a laser ablation phenomenon occurs on the surface of the target 141,
Ultrafine particles 142 are generated by promoting association and growth in the air. With respect to the generated fine particles 142, the mass separation unit 1
44 is used to control the particle size of the ultrafine particles that reach the deposition substrate 143. The mass separation section 144 is provided with ultrafine particles 14.
2, an orifice 145 for introducing 2, an ionization chamber 146 for ionizing the introduced ultrafine particles, an acceleration tube 147 for accelerating the velocity of the ionized ultrafine particles, and an electric field for mass-separating the ultrafine particles. It is composed of a deflection electrode 148 to be applied.

Next, a method for controlling the particle size of the ultrafine particles in the above structure will be described. First, as described above, the target 141 placed in the vacuum reaction chamber in the rare gas atmosphere is used.
When the surface of the is irradiated with pulsed laser light, ultrafine particles 142 are generated. The ultrafine particles 142 pass through the orifice 145 and are introduced into the ionization chamber 146. A glow discharge region is formed in the ionization chamber 146, and the introduced ultrafine particles are ionized when passing through the glow discharge region. Next, the ionized ultrafine particles reach the deflection electrode 148 after being accelerated according to the voltage applied to the acceleration tube 147. Here, the deflection electrode 1
By applying an electric field to 48, the emission direction of some of the ultrafine particles can be changed to the direction of the deposition substrate 143. This injection direction is the particle size of the ultrafine particles to be deposited (to be exact, the mass),
Since it is determined by the accelerating voltage at the accelerating tube 147 and the electric field applied at the deflecting electrode 148, only the ultrafine particles to be deposited can be ejected toward the deposition substrate 143 by controlling these physical quantities.

Therefore, the above mass separation section 144 is
By incorporating it between the target 141 and the deposition substrate 143, it becomes possible to deposit ultrafine particles having a uniform particle size on the deposition substrate 143.

In the above description, the electric field was applied using the deflection electrode to change the emitting direction of the ultrafine particles.
It is also possible to change the emission direction by applying a magnetic field.

[0199]

As described above, according to the present invention, an optoelectronic material layer containing an optoelectronic material dispersed in a substantially homogeneous medium in which electrical properties such as conductivity can be controlled, and the optoelectronic material. A photoelectric conversion layer having a pair of electrodes provided above and below the layer and having a light-receiving function by detecting a change in internal resistance and photoelectromotive force due to generation of carriers corresponding to light irradiation to the optoelectronic material layer. By controlling the optical gap energy of the ultrafine particles, a photoelectric conversion layer having a light receiving function in a predetermined wavelength region different from each other has a structure in which a transparent insulator film is laminated, Providing a color sensor with a simple structure that does not require a color filter, etc., using an optoelectronic material that is a material that is buried and free of environmental pollution and that has Si-LSI technology compatibility, environmental resistance, and assembly-less properties. It can be.

[Brief description of drawings]

FIG. 1 is a cross-sectional structural diagram of a light emitting device according to an embodiment of the present invention.

FIG. 2 is a current-voltage characteristic curve diagram of the light emitting device.

FIG. 3 is a diagram showing a light emission intensity-current characteristic curve of the light emitting device.

FIG. 4 is a light intensity-duty ratio characteristic curve diagram of the light emitting element.

FIG. 5: PL and EL emission intensity-photon energy characteristic curve diagram of the same light emitting device

FIG. 6 is a sectional structural view of the photoelectric conversion element.

FIG. 7 is a cross-sectional structure diagram of the photoelectric conversion element.

FIG. 8 is a sectional structural view of the color sensor.

FIG. 9 is an absorption spectrum diagram of each photoelectric conversion layer of the color sensor.

FIG. 10 is a sectional structural view of the same optoelectronic material.

FIG. 11 is an emission spectrum diagram of the same optoelectronic material.

FIG. 12 is a sectional structural view of the same optoelectronic material.

FIG. 13 is a conceptual diagram of the optoelectronic material manufacturing apparatus.

FIG. 14 is a conceptual diagram of a particle size control device for ultrafine particles in the same embodiment.

FIG. 15 is a cross-sectional structure diagram of an EL element using conventional porous Si.

FIG. 16 is a sectional structural view of a conventional light emitting device using porous Si.

FIG. 17 is a sectional structural view of a conventional photodiode.

FIG. 18 is a cross-sectional structure diagram of a conventional integrated single-plate color sensor.

[Explanation of symbols]

11, 61, 71, 101, 121 Substrates 12, 62, 88 Separation insulating films 12a, 62a Openings 13, 63, 73, 84 Optoelectronic material layers 14, 64, 74, 85, 105, 125 Ultrafine particles 15, 65, 75, 86, 104, 126 transparent medium 16, 66, 76, 87 semi-transparent electrode 17, 67 back electrode 18, 68 conductive paste 72 lower electrode 81, 82, 83 first, second and third photoelectric conversion layer 102 transparent material Layer 103 Ultrafine particle dispersion layer 122 Metal thin film layer 123 Multilayer film layer 124 Active layer 127 Partial reflection film layer 1301 First reaction chamber 1302, 1309 Mass flow controller 1303 Noble gas introduction line 1304, 1311 Gas exhaust system 1305 First target holder 1306 Si Target 1307 First pulsed laser light source 1308 Second reaction chamber 1310 Oxidation Gas Line 1312 second target holder 1313 SnO ₂ target 1314 second pulse laser source 1315 vacuum reaction chamber 1316 deposition substrate 1317 high vacuum evacuation system 1318 first nozzle 1319 second nozzle 141 Target 142 generates ultrafine particles 143 deposited substrate 144 mass separation unit 145 Orifice 146 Ionization chamber 147 Accelerating tube 148 Deflection electrode

Continuation of the front page (56) Reference JP-A-8-181341 (JP, A) JP-A-4-112584 (JP, A) JP-A-3-243687 (JP, A) JP-A-1-149488 (JP , A) JP-A-3-289523 (JP, A) JP-A-10-12898 (JP, A) US Pat. No. 4625071 (US, A) International Publication 98/04006 (WO, A1) (58) Fields investigated ( Int.Cl. ⁷ , DB name) H01L 31/00-31/119 G01J 3/00-3/52

Claims (28)

(57) [Claims] 1. An optoelectronic material layer containing an optoelectronic material in which ultrafine particles have a controllable electric conductivity or dielectric constant and dispersed in a substantially homogeneous medium, and 1 provided above and below the optoelectronic material layer. A pair of electrodes, a photoelectric conversion layer having a light receiving function by detecting a change in internal resistance due to carrier generation corresponding to light irradiation to the optoelectronic material layer, the average particle size of the ultrafine particles or A color sensor in which the photoelectric conversion layers having a light receiving function in predetermined wavelength regions different from each other by adjusting the structure of the surface atomic arrangement to control the optical gap energy are laminated via a transparent insulator film. . 2. An optoelectronic material layer containing an optoelectronic material in which ultrafine particles are controllable in conductivity or dielectric constant and dispersed in a substantially homogeneous medium, and 1 provided above and below the optoelectronic material layer. A pair of electrodes, and a Schottky junction at the interface between the optoelectronic material layer and the electrode, or a pn junction inside the optoelectronic material layer is formed, and a photoelectromotive force due to carrier generation by light irradiation is detected. A photoelectric conversion layer having a light-receiving function by controlling the optical gap energy by adjusting the average particle size of the ultrafine particles or the structure of the surface atomic arrangement, thereby providing a light-receiving function in mutually different predetermined wavelength regions. A color sensor in which the photoelectric conversion layer having the above is laminated via a transparent insulator film. 3. The photoelectric conversion layer, when minority carriers are injected into the ultrafine particles of the optoelectronic material layer by a pair of electrodes,
The color sensor according to claim 1 or 2, which also has a light emitting function of exhibiting a light emitting phenomenon due to a radiative recombination process of the generated electron-hole pairs. 4. The stacked photoelectric conversion layers have different optical gap energies from each other and are closer to the light receiving surface,
The color sensor according to claim 1, wherein the optical gap energy is large. 5. The color sensor according to claim 1, comprising three photoelectric conversion layers exhibiting different optical gap energies in the visible light region. 6. The color sensor according to claim 1, wherein the pair of electrodes are transparent or semitransparent electrodes. 7. The color sensor according to claim 1, wherein the ultrafine particles contain a group IV semiconductor. 8. The ultrafine particles are III-V group or II-
7. The color sensor according to claim 1, which comprises a Group VI compound semiconductor. 9. The medium is a thin film conductor.
9. The color sensor according to any one of 1 to 8. 10. The color sensor according to claim 1, wherein the medium is a thin film dielectric. 11. The optoelectronic material layer comprises an ultrafine particle-dispersed layer containing an optoelectronic material in which ultrafine particles have a controllable electric conductivity or a dielectric constant and dispersed in a substantially homogeneous medium, and a transparent material layer are alternately arranged. The color sensor according to any one of claims 1 to 10, which has a periodic structure laminated on. 12. The color sensor according to claim 11, wherein the transparent material layer is a conductor thin film. 13. The color sensor according to claim 11, wherein the transparent material layer is a dielectric thin film. 14. The optoelectronic material layer comprises an active layer containing ultrafine particles, a highly reflective layer provided below the active layer, and a partially reflective layer provided above the active layer. 11. The color sensor according to any one of 1 to 10. 15. The color sensor according to claim 14, wherein at least one of the partially reflective layer and the highly reflective layer is a metal thin film. 16. The color sensor according to claim 14, wherein at least one of the partially reflective layer and the highly reflective layer is a multilayer film layer having a periodic structure in which at least two types of layers having different refractive indexes are alternately laminated. 17. A highly reflective layer, which is a multilayer film layer having a periodic structure in which at least two types of layers having different refractive indexes are alternately laminated,
The color sensor according to claim 14, further comprising a metal thin film layer. 18. The optoelectronic material comprises a first target material arranging step of arranging a first target material inside a vacuum reaction chamber in a low-pressure rare gas atmosphere, and a substrate arranging step of arranging a deposition substrate inside the vacuum reaction chamber. A second target material arranging step of arranging a second target material in a reaction chamber isolated from the first target material and the deposition substrate as an atmospheric component, and arranging in the first target material arranging step An ablation step of irradiating the irradiated first target material with laser light to cause detachment / injection of the target material;
And an evaporation step of evaporating the second target material arranged in the second target material arrangement step, wherein the material obtained by desorption and injection in the ablation step is condensed and grown in the air. Substantially at the same time that the fine particles are collected on the deposition substrate, the substances produced in the evaporation step are collected on the deposition substrate to be contained in the substance composed of the second target material. Obtained by a manufacturing method for obtaining an optoelectronic material in which ultrafine particles are dispersed.
7. The color sensor according to any one of 7. 19. The color sensor according to claim 18, wherein in the evaporation step of evaporating the second target material, a laser is used to evaporate the second target material. 20. The evaporation step of evaporating the second target material includes an ablation step of irradiating the second target material with a second laser beam to cause desorption / injection of the target material. Color sensor. 21. The color sensor according to claim 18, wherein the first target material includes a semiconductor. 22. The color sensor according to claim 18, wherein the second target material is a conductor. 23. The method for producing an optoelectronic material according to claim 18, wherein the second target material is a dielectric. 24. The received photon energy is controlled by adjusting the particle size of the ultrafine particles.
The color sensor according to any one of 1. 25. The color sensor according to claim 24, wherein the average particle size of the ultrafine particles is controlled by changing the introduction pressure of the low pressure rare gas. 26. The color sensor according to claim 24, wherein the average particle size of the ultrafine particles is controlled by a step of mass-separating the ultrafine particles obtained by the ablation step. 27. The step of mass-separating the ultrafine particles includes a step of ionizing the ultrafine particles and a step of applying an electric field or a magnetic field to the ionized ultrafine particles.
6. The color sensor according to 6. 28. The color sensor according to claim 1, wherein the received photon energy is controlled by adjusting the structure of the surface atom arrangement of the ultrafine particles.