JP2001210865A - Light emitting element and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light emitting element which can easily be manufactured and operated, and to provide a manufacturing method. SOLUTION: A structure where a hole transportation layer 22 and a semiconductor light emitting layer 23 are sequentially laminated on a substrate 21 is provided. The hole transportation layer 22 is constituted of the nitride of a 3B group element, to which acceptor impunity is added. The semiconductor light emitting layer 23 is constituted of a fine grain sintered body. In the fine grain sintered body, fine grains including crystallite constituted of the oxide of ZnO are jointed by sintering, a grain boundary energy barrier among the fine grains is small and electron transportation property is given. Thus, it can easily be operated by the DC current of low voltage. The substrate 21 can arbitrarily be selected, an area is made to be large and cost can be reduced. Then, the minute control of the hole transportation layer, the crystal system of the semiconductor light emitting layer 23 and a lattice constant is not necessary and the element can easily be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device using a fine particle sintered body containing semiconductor microcrystals and a method for manufacturing the same.

[0002]

2. Description of the Related Art Among light emitting devices which operate by direct current, a blue light emitting diode (Blue-LED;
lue Light Emitting Diode
e), ultraviolet light emitting diode (UV-LED; Ultra)
-Violet Light Emitting Di
gallium nitride (GaN), indium nitride, etc.
Group III nitride compound semiconductors represented by gallium mixed crystal (InGaN), aluminum nitride-gallium mixed crystal (AlGaN), or indium aluminum-gallium mixed crystal (InAlGaN) have been attracting attention, and their research and development have been active. Is being done.

[0003] Conventionally, such a group III nitride compound semiconductor has been produced by MOCVD (Metal Organic C).
chemical Vapor Deposition;
Metal organic chemical vapor deposition (MOVPE (Metal)
Organic Vapor Phase Epita
xy) method) or MBE (Molecula)
r Beam Epitaxy; molecular beam epitaxy)
It is fabricated as a single-crystal thin film by growing it on a substrate using a method.

In the MOCVD method, a group 3 element and a nitrogen source gas are chemically reacted to form a 3
This is a method of heteroepitaxially growing a group III nitride compound semiconductor, and has an advantage that a single crystal thin film having a uniform composition can be formed. In addition, since the substrate temperature (growth temperature) can be set high, there is also an advantage that a so-called single crystal thin film having high crystallinity with few lattice defects such as dislocations can be relatively easily formed. .

On the other hand, the MBE method is a method of growing a crystal by irradiating a substrate with a particle beam of a group III element and nitrogen evaporated from a Knudsen cell, and forming a thin film having a uniform composition and thickness. Is difficult,
In order to suppress the desorption of nitrogen from the surface of the thin film during growth, the substrate temperature must be lowered, and there is a problem that it is difficult to produce a single crystal thin film having high crystallinity. In general, it is said that the luminous efficiency of a light-emitting element strongly depends on crystallinity. Therefore, at present, a practically effective MOCVD method is often used.

However, when a light emitting device is manufactured by the MOCVD method, the substrate to be used needs to have a crystal lattice constant substantially equal to that of the compound semiconductor to be grown and to have excellent heat resistance. That is, there is a problem that the material and size of the substrate are restricted.

For example, when growing a group III nitride compound semiconductor, crystalline sapphire (α-A
l ₂ O ₃ ) substrate is used. This sapphire is
It has a crystal lattice constant substantially equal to that of gallium nitride, and has excellent heat resistance, and is a suitable material for a substrate for MOCVD.
However, when a sapphire substrate is used, it must be grown on the c-plane, so that there is a problem in workability and moldability of the substrate, and there is a problem that the material cost is increased.

Further, it is difficult to form a thin film having a uniform film thickness over the entire surface of the substrate, so that a substrate having a large area cannot be used. There was also a problem.

Furthermore, since the light-emitting element has a multilayer structure composed of a light-emitting layer (also called an active layer) and a carrier transport layer, a compound semiconductor is epitaxially grown so that crystal lattice distortion does not occur at the junction surface of each semiconductor layer. Need to be done. The reason is that when crystal lattice distortion occurs,
This is because crystal lattice defects such as dislocations are generated in the vicinity of the junction surface of each semiconductor layer, and the luminous efficiency is reduced. That is, it is necessary to precisely control the crystal system and lattice constant of each semiconductor layer, and there is a problem that setting and controlling the crystal growth conditions is extremely difficult, and manufacturing is difficult.

[0010] In addition to the group III nitride compound semiconductor, an oxide semiconductor is a practical semiconductor material used for a light emitting element. Features of oxide semiconductors are:
A crystal can be grown at a lower temperature as compared with a group nitride compound semiconductor.

[0011] Among oxide semiconductors, for example, zinc oxide (ZnO) is known as a direct transition type light emitting material having a bandgap energy of 3.2 eV. Further, the exciton binding energy of zinc oxide is 60 meV, which is larger than 24 meV of gallium nitride, and it is considered that excitons are stably present even at room temperature. Therefore, a light-emitting element that emits excitons at room temperature can be realized, and there are many documents on exciton emission of zinc oxide in the past.

For example, the oldest known literature on a light-emitting element using zinc oxide as a light-emitting layer includes “ZINC”.
OXIDE LIGHT EMITTING DIO
DE "(US Patent: No. 408176)
4, Date: March 28, 1978). In this document, an MS (Metal Semiconductor) in which an anode electrode and a cathode electrode are formed on a single-crystal zinc oxide flake and a DC voltage is applied between the electrodes to operate.
or) A light emitting element having a structure has been proposed. Generally, MS
A light emitting device having a structure has a Schottky barrier (Shotky barrier) formed on a semiconductor surface by contact between a metal and a semiconductor.
In this case, the rectifier characteristic is developed and operated using the same. The feature of the light-emitting element proposed in this patent is that the crystal lattice plane of oxygen atoms is exposed on one side of a single crystal zinc oxide flake, and an anode electrode using a material having a large work function is formed on the crystal lattice plane. Thus, the rectification characteristic is exhibited. Therefore, in this light-emitting element, a process technology for precisely exposing the crystal lattice plane of the single crystal zinc oxide and a process technology for properly bonding the crystal lattice plane to the anode electrode are indispensable, and the production is difficult. was there.

Further, in the past literature, a DC pulse current (frequency: 10 Hz to
MIS (Metal Ins) operating at 1 kHz)
A light-emitting element having a structure of a semiconductor (ultrator semiconductor) has been proposed. The light-emitting element having the MIS structure is a general term for a light-emitting element that controls a semiconductor surface via an insulator by applying a voltage to a metal electrode.

For example, as such a light emitting element, a silver (Ag) electrode, an insulating layer made of silicon oxide (SiO), a light emitting layer made of zinc oxide to which lithium (Li) is added, and a silver electrode are sequentially laminated. (BW.
Thomas et al. : Electronics
Letters, vol. 9, No. 16, p. 36
2 (1973). And a structure in which a gold (Au) electrode, an insulating layer made of silicon oxide, a light emitting layer made of zinc oxide, and a gold electrode are sequentially laminated (T. Minami).
et al. : Jpn. J. Appl. Phys. , V
ol. 13, No. 9, p. 1475 (197
4). ), And a structure in which a gold electrode, an insulating layer made of zinc oxide, a light emitting layer made of zinc oxide, and an indium (In) electrode are sequentially laminated (A. Shimizu, Japan).
t al. : Jpn. J. Appl. Phys. , Vo
l. 17, No. 8, p. 1435 (1978). )and so on. The feature of these MIS structure light emitting elements lies in that voltage control rather than current control is used in the structure. Therefore, the light emitting element having the MIS structure cannot be operated by a DC current of a battery or the like, but is operated by a DC pulse current of a pulse generator or the like. Therefore,
A drive circuit for generating a DC pulse current is required, and there is a problem that the price of the entire system increases. Further, in principle, the structure in which an insulating layer is introduced has a problem of dielectric breakdown in which an overcurrent flows at the time of driving, and has a problem in reliability and stability.

Furthermore, a recent publicly known document proposes a light-emitting element that oscillates a laser using a light-emitting layer of zinc oxide composed of hexagonal columnar microcrystals (Japanese Patent Laid-Open No. 10-2).
No. 56673, "Optical semiconductor device and manufacturing method thereof"). The feature of this light emitting element is that the crystal grain boundaries (six places on the side surfaces) of zinc oxide made of hexagonal columnar microcrystals actively function as resonator mirrors. Therefore, in this light-emitting element, a microcrystal manufacturing technique capable of precisely forming the hexagonal prism structure of the microcrystal geometrically and controlling the side-to-side spacing of the hexagonal prism is indispensable, and it is difficult to manufacture. There was a problem.

[0016] In addition, according to recent known literature, the average particle size is 2
There has been proposed a light-emitting element using an n-type semiconductor light-emitting layer having a single-layer film or a multilayer film structure in which microcrystals having a particle size equal to or less than 0 nm are regularly arranged (“ELECTROLUMINES”).
CENT DEVICESFORMED USING
SEMICONDUCTOR NANOCRYSTAL
S AS ELECTRON TRANSPORT
T MEDIA AND METHOD OF MAK
ING SUCH ELECTROLUMINESSE
NT DEVICES "(US Patent: N
o. 5537000, Date: July 16, 199
6)). The feature of this light-emitting element is that a quantum size effect is exhibited by using microcrystals having an average particle diameter of 20 nm or less and having the same particle diameter, and the emission wavelength can be controlled by the crystal particle diameter. Therefore, in this light-emitting element, a crystal grain boundary between crystallites needs to be clearly present in order to exhibit the quantum size effect, so that the interface energy between the crystallites is inevitably increased, and the driving voltage is reduced. The problem that it becomes high is considered.

[0017]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a light emitting device which can be easily manufactured and which can be easily operated, and a method of manufacturing the same. To provide.

[0018]

According to the present invention, there is provided a light emitting device comprising a hole transport layer and a fine particle sintered layer formed on one side of the hole transport layer, wherein fine particles containing semiconductor microcrystals are joined by a sintered region. A semiconductor light emitting layer made of a body, a first electrode electrically connected to the hole transport layer,
A second electrode electrically connected to the semiconductor light emitting layer.

In another light emitting device according to the present invention, a hole transport layer, an electron transport layer, and fine particles containing semiconductor microcrystals formed between the hole transport layer and the electron transport layer are bonded by a sintered region. A semiconductor light emitting layer made of a fine particle sintered body, a first electrode electrically connected to the hole transport layer, and a second electrode electrically connected to the electron transport layer. It is provided with.

In another light emitting device according to the present invention, a semiconductor light emitting layer made of a fine particle sintered body in which fine particles containing semiconductor microcrystals are joined by a sintered region, and the semiconductor light emitting layer is electrically connected to each other. It has a first electrode and a second electrode.

The method of manufacturing a light emitting device according to the present invention comprises a step of forming a hole transport layer on a substrate, and a step of sintering fine particles containing semiconductor microcrystals on the hole transport layer. Forming a semiconductor light emitting layer.

Another method for manufacturing a light emitting device according to the present invention is as follows.
A step of forming a hole transport layer on the substrate, a step of forming a semiconductor light emitting layer on the hole transport layer by a fine particle sintered body obtained by sintering fine particles containing semiconductor microcrystals, and a step of forming the semiconductor light emitting layer A step of forming an electron transport layer thereon.

In the light emitting device according to the present invention and other light emitting devices, when a current is injected into the semiconductor light emitting layer through the first electrode and the second electrode, light is generated in the semiconductor light emitting layer. Here, since the semiconductor light emitting layer is formed by the fine particle sintered body in which the fine particles containing the semiconductor microcrystals are joined in the sintered region, the carrier transportability in the semiconductor light emitting layer is ensured.

In the method for manufacturing a light emitting device according to the present invention and another method for manufacturing a light emitting device, a semiconductor light emitting layer is formed of a fine particle sintered body obtained by sintering fine particles containing semiconductor microcrystals.

[0025]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 conceptually shows a configuration example of a fine particle sintered body 10 constituting a semiconductor light emitting layer of a light emitting device according to an embodiment of the present invention. Note that FIG. 1 conceptually illustrates the configuration of the fine particle sintered body 10 for the sake of explanation, but does not illustrate the actual product.

The fine particle sintered body 10 has a structure in which fine particles 11 containing microcrystals made of a semiconductor are joined by a sintered region 11a. This is obtained by sintering the fine particles 11 as shown in FIG. In the aggregate of the fine particles 11 shown in FIG. 2, a high grain boundary energy barrier (double Schottky barrier) exists at the interface between the fine particles and there is no carrier transporting property. Due to the sintering region 11a, the grain boundary energy barrier between the fine particles is reduced, and the carrier transportability between the fine particles can be secured. Thereby, the fine particle sintered body 10 has a specific resistance of, for example, 0.001 Ωcm to 100 Ωcm.
A carrier transporting property of about 00 Ωcm can be obtained.

The fine particles 11 constituting the fine particle sintered body 10 are at least partially composed of microcrystals, and may include, for example, microcrystals and particles other than microcrystals. For example, fine particles in which a coating layer or the like is provided on microcrystals may be included. Here, the term “microcrystal” refers to fine particles made of a single crystal or polycrystal.
The crystal grain size of the microcrystal (that is, the crystal grain size of one single crystal) is preferably 100 nm or less. 100n
This is because a crystal with very few defects can be obtained if the number is less than m. Further, a more preferable crystal grain size of the microcrystal is 50 nm or less. As the crystal grain size becomes smaller, the surface free energy of the microcrystals increases, and heat treatment or laser annealing enables modification of the microcrystal surface and solid phase sintering between the microcrystals at lower temperature conditions. This is because luminance and mechanical strength can be improved.

The fine particle sintered body 10 emits forbidden band transition light emission (light emission due to forbidden band transition) or donor-acceptor pair light emission (light emission due to transition between donor-acceptor levels). ing. That is, the fine particle sintered body 10 has a forbidden band transition emission function or a donor-acceptor pair emission function.

Examples of the semiconductor constituting microcrystals include oxides and nitrides. For example, zinc (Zn),
An oxide containing at least one selected from the group consisting of titanium (Ti) and iron (Fe), a nitride of a Group 3B element, or the like is preferable. Specifically, zinc oxide, titanium oxide (TiO ₂ ), iron oxide (Fe ₂ O ₃ or FeO), zinc oxide / titanium oxide (ZnO · TiO ₂ ) mixed crystal, zinc oxide / iron oxide (ZnO · Fe ₂₎ O ₃ ) mixed crystal or titanium oxide / iron oxide (TiO ₂ / Fe ₂ O ₃ ) mixed crystal, or gallium nitride, indium nitride, indium nitride / gallium mixed crystal, aluminum nitride / gallium mixed crystal or indium / aluminum / nitride Gallium mixed crystal and the like can be mentioned.

The microcrystal may contain an n-type impurity as necessary. Incidentally, in the case where microcrystals are formed using an oxide, an n-type semiconductor having an electron-transporting property is often obtained because carriers are often based on oxygen vacancies.

Fine particle sintered body 10 having such a configuration
Can be manufactured as follows.

First, the above-mentioned fine particles 11 containing microcrystals made of a semiconductor are dispersed in a solution to prepare a coating solution. Note that the crystal grain size of the microcrystal is preferably 100 nm or less, and more preferably 50 nm or less, as described above.

As a solution for dispersing the fine particles 11, for example, an organic solvent containing at least one organic compound having one or more hydroxyl groups is preferable. Specifically, monohydric alcohols represented by ethanol, methanol, n-propyl alcohol, i-propyl alcohol, 1-butanol or 2-butanol, or ethylene glycol, diethylene glycol, 2-methoxyethanol, 2-ethoxyethanol Alternatively, dihydric alcohols and derivatives thereof represented by triethylene glycol, trihydric or higher polyhydric alcohols represented by glycerin, and aromatic compounds such as phenol and cresol are exemplified. May be used as a mixture, or at least one of these may be used as a mixture with another organic compound.

The amount of the solution in which the fine particles 11 are dispersed can be set arbitrarily, but it should be noted that this controls the thickness of the coating when the coating solution is applied. The dispersion method of the fine particles 11 may be a conventional dispersion means such as stirring, a ball mill, a sand mill, and ultrasonic dispersion, and a uniform coating solution can be easily obtained by these dispersion means.

Next, this coating solution is applied on an appropriate substrate (not shown), and dried naturally or dried by heating in an oven to form a coating layer. At this time, the substrate includes, for example, a glass substrate, a ceramic substrate, a sapphire substrate,
Boron nitride (BN) substrate, aluminum nitride substrate, gallium nitride substrate, aluminum / gallium nitride substrate, indium / gallium nitride substrate, silicon carbide (SiC) substrate, silicon (Si) substrate or metal substrate, or polycarbonate resin, polyethylene terephthalate resin , Polyester resin, epoxy resin, acrylic resin or ABS (Acrylonitrile-Buta)
A resin substrate made of, for example, a diene-styrene copolymer resin can be used.

The method of applying the coating solution may be arbitrary, and various methods such as spin coating, dip coating, spray coating, roll coating, meniscus coating, bar coating, curtain flow coating, and bead coating may be used. Can be. The application and the drying are repeated until the coating layer has a predetermined thickness.

Subsequently, the coating layer is sintered by heating. Thereby, solid-phase sintering between the fine particles in the coating layer is promoted, the grain boundary energy barrier between the fine particles is relaxed, and the mechanical strength is increased by densification. That is, the fine particle sintered body 10 shown in FIG. 1 is obtained. At that time, for example, heating may be performed using a firing furnace such as an electric firing furnace, or heating may be performed by irradiating an energy beam such as a laser beam.

For example, when sintering the fine particles 11 containing microcrystals of an oxide such as zinc oxide using a firing furnace, the content ratio of oxygen (O ₂ ) is 60 mol% or more, preferably 90 mol% or more. In a gas atmosphere of 600
It is preferable to heat at a temperature of about ° C. The content ratio of oxygen is set to 60 mol% or more, more preferably 90 mol% or more, because when the oxygen content ratio is low, oxygen is desorbed from the surface of the microcrystal at the time of heating and oxygen deficiency increases. When sintering the fine particles 11 containing microcrystals made of nitride, nitrogen (N ₂ ) is introduced into the gas atmosphere instead of oxygen.

For example, when sintering the fine particles 11 containing microcrystals made of oxide by irradiating a laser beam, the oxygen content ratio is 60 mol% or more, preferably 9 mol% or more.
In a gas atmosphere of 0 mol% or more, it is preferable to irradiate an excimer laser beam with an energy density of about 150 mJ / cm ² . Making the oxygen content ratio in this way is the same as in the case of using a firing furnace. When firing fine particles 11 containing microcrystals of nitride, nitrogen may be introduced instead of oxygen. As the excimer laser beam, for example, XeCl (wavelength 308 n)
m), XeF (wavelength 351 nm), XeBr (wavelength 28
2 nm), KrF (wavelength 248 nm), KrCl (wavelength 222 nm) or ArF (wavelength 193 nm), F ₂
(Wavelength: 157 nm) or the like having a wavelength in the ultraviolet region oscillated by using a wavelength of 157 nm or the like.

The fine particle sintered body 10 operates as follows.

In the fine particle sintered body 10, when a current is injected, light emission occurs due to electron-hole recombination caused by a band gap transition or a transition between donor-acceptor levels. Here, since the fine particles 11 are joined by the sintering region 11a, carrier transportability between the fine particles is ensured, and good light emission can be obtained at a low voltage.

As described above, according to the fine particle sintered body 10, the fine particles 11 are sintered, and the fine particles 11
Thus, the grain boundary energy barrier between the fine particles can be reduced, and the carrier transportability between the fine particles can be ensured. Therefore, good light emission can be easily obtained at a low voltage. In addition, the sintering region 1
1a, high mechanical strength can be obtained.

Such a fine particle sintered body 10 is used for the light emitting device according to the present embodiment as follows.

(First Light-Emitting Element) FIG. 3 shows a light-emitting diode (light) as a first light-emitting element according to this embodiment.
This represents a schematic configuration of an emitting diode (LED). (A) is a planar structure viewed from the electrode side, and (B) is a cross-sectional structure along the II line of (A). This light emitting diode is mounted on a substrate 21
It has a structure in which the hole transport layer 22 as the first conductivity type layer and the semiconductor light emitting layer 23 made of the above-described sintered fine particles 10 are stacked adjacently in this order. As the substrate 21, for example, the various substrates described in the method for manufacturing the fine particle sintered body 10 can be used.

The hole transport layer 22 has, for example, a thickness in the stacking direction (hereinafter simply referred to as a thickness) of about 0.1 μm to 10 μm.
m, and is made of a nitride of a Group 3B element to which a p-type impurity such as magnesium (Mg) is added. The carrier concentration of the hole transport layer 22 is, for example, 1.0 × 10
It is about ¹⁶ cm ⁻³ to 1.0 × 10 ²⁰ cm ⁻³ . Note that the hole transport layer 22 may have any form such as a single crystal, a polycrystal, an amorphous, a fine particle, or a composite thereof.

The hole transport layer 22 preferably has a larger bandgap energy than the semiconductor light emitting layer 23. This is because the hole transport layer 22 can function as a carrier confinement for the semiconductor light emitting layer 23 and as a cladding layer. In addition, the wavelength of light emitted from the semiconductor light emitting layer 23 is longer than the absorption edge wavelength of the hole transport layer 22, and the light emitted from the semiconductor light emitting layer 23 is not attenuated in the hole transport layer 22. This is because light is transmitted, so that light can be extracted from the side of the substrate 21 and light extraction efficiency can be increased.

For example, as described later, the semiconductor light emitting layer 23
When the hole transport layer 22 is constituted to contain microcrystals of zinc oxide, titanium oxide or iron oxide, it is preferable that the hole transport layer 22 is composed of boron nitride, aluminum nitride, gallium nitride, aluminum nitride-gallium mixed crystal, or the like. . Incidentally, their bandgap energies are 3.2 eV for zinc oxide, 3.0 eV for titanium oxide, 3.1 eV for iron oxide (Fe ₂ O ₃ ), and 6.2 e for boron nitride.
V, aluminum nitride is 6.1 eV, and gallium nitride is 3.4 eV. In the case of a mixed crystal, it changes according to the composition.

The semiconductor light emitting layer 23 has a thickness of, for example, about 0.5 μm to 10 μm, and is made of the fine particle sintered body 10 containing microcrystals made of oxide. As the oxide, for example, as described above, an oxide containing at least one member from the group consisting of zinc, titanium, and iron can be used. The fine particle sintered body 10 has, for example, carriers due to oxygen deficiency, whereby the semiconductor light emitting layer 23 is an electron transport layer which is a second conductivity type layer.

On the hole transport layer 22, a p-side electrode 24 as a first electrode is formed, and on the semiconductor light emitting layer 23, an n-side electrode 25 as a second electrode is formed. . The p-side electrode 24 is electrically connected to the semiconductor light emitting layer 23 via the hole transport layer 22 and the hole transport layer 22, for example, a nickel (Ni) layer and a platinum (Pt) layer from the hole transport layer 22 side. And a gold (Au) layer sequentially laminated and alloyed. n-side electrode 25
Is electrically connected to the semiconductor light emitting layer 23 and has, for example, a structure in which a gold layer is deposited and alloyed. Note that n
The side electrode 25 is preferably formed on almost the entire surface of the semiconductor light emitting layer 23. This is because the contact area between the semiconductor light emitting layer 23 and the n-side electrode 25 increases, and light emission can be obtained from almost the entire surface of the semiconductor light emitting layer 23.

The light emitting diode having such a configuration can be manufactured as follows.

First, on the cleaned substrate 21, for example,
MOCVD, MBE, PLD (Pulsed La
ser Deposition; pulse laser deposition)
Method, sputtering method or CVD (Chemica
The hole transport layer 22 is formed by using an I Vapor Deposition method or the like.

Next, the semiconductor light emitting layer 23 is formed on the hole transport layer 22 by the above-described method. Subsequently, a stripe-shaped resist pattern (not shown) is formed on the semiconductor light emitting layer 23, for example, corresponding to the formation position of the p-side electrode 24, and using this resist pattern as a mask, for example, reactive ion etching (RIE; Reactive)
Ion Etching) semiconductor light emitting layer 23
Is selectively removed to expose the hole transport layer 22.

After exposing the hole transport layer 22, the resist pattern (not shown) is removed, and for example, a gold layer is deposited on the semiconductor light emitting layer 23 to form the n-side electrode 25, and the exposed hole transport layer 22 is formed. For example, a p-side electrode 24 is formed by sequentially depositing a nickel layer, a platinum layer, and a gold layer on the metal layer 22. After that, a heat treatment is performed to alloy the p-side electrode 24 and the n-side electrode 25. As a result, FIG.
The light emitting diode shown in (B) is obtained.

The light emitting diode manufactured as described above operates as follows.

The light emitting diode operates by a direct current, and when a predetermined voltage is applied between the p-side electrode 24 and the n-side electrode 25, a current is injected into the semiconductor light emitting layer 23 and the semiconductor light emitting layer 23 Light emission occurs due to electron-hole recombination near the interface with the hole transport layer 22. Here, since the microcrystals included in the semiconductor light emitting layer 23 are composed of an oxide, ultraviolet light or visible light is emitted. Also,
Since the semiconductor light emitting layer 23 is composed of the fine particle sintered body 10, carrier transportability in the semiconductor light emitting layer 23 is secured, and good light emission can be obtained at a low voltage.

The light emitting diode is used as a light source such as a lighting, a display or a germicidal lamp.

As described above, according to this light emitting diode,
Since the semiconductor light emitting layer 23 made of the fine particle sintered body 10 is provided, carrier transportability in the semiconductor light emitting layer 23 can be secured, and the semiconductor light emitting layer 23 can be easily operated with a low voltage DC current. Therefore, a complicated and expensive drive circuit is not required, and the device can be used as a display element of an electric product used outdoors such as a mobile phone.

Further, it can be formed on an arbitrary substrate 21, and it is not necessary to use a substrate having excellent heat resistance as compared with the case where it is formed by an epitaxial growth method such as MOCVD. Therefore, the material of the substrate 21 can be arbitrarily selected, the area of the substrate 21 can be increased, and the manufacturing cost can be reduced. Therefore, a large-sized display element such as a large-area display and a large-area lighting fixture can be realized.

Further, when forming the semiconductor light emitting layer 23,
There is no need to precisely control the crystal system and lattice constant, and it can be easily manufactured.

In addition, according to this light emitting diode, since microcrystals are formed by an oxide such as zinc oxide, ultraviolet light can be easily emitted at room temperature. Therefore, by using it as a phosphor excitation light source,
It can be applied to displays, lighting equipment and the like.
For example, in an image display device based on the coloring of a phosphor,
CRT (Cathode Ray Tube) electron gun and FED (Field Emission Display)
By using it as an excitation energy source instead of the cold cathode in y), a large flat display can be realized.

(Second Light-Emitting Element) FIG. 4 conceptually shows the structure of a light-emitting diode as a second light-emitting element according to the present embodiment. (A) is a planar structure viewed from the electrode side, and (B) is a cross-sectional structure along the line II-II in (A). In this light-emitting diode, an electron transport layer 36 as a second conductivity type layer is provided between the semiconductor light-emitting layer 23 and the n-side electrode 25, and the n-side electrode 25 is connected to the semiconductor light-emitting layer 23 via the electron transport layer 36. Except for being electrically connected, it has the same configuration as the first light emitting element. Therefore, here, the same components are denoted by the same reference numerals, and detailed description thereof will be omitted.

The electron transporting layer 36 has, for example, a thickness of about 0.3 mm.
5 μm to 10 μm, and is made of a nitride of a Group 3B element to which an n-type impurity such as silicon (Si) is added. The carrier concentration of the electron transport layer 36 is, for example, 1.0
It is about × 10 ¹⁷ cm ^{−3 to} 1.0 × 10 ²⁰ cm ⁻³ . Note that, like the hole transport layer 22, the electron transport layer 36 may have any form such as a single crystal, a polycrystal, an amorphous, a fine particle, or a composite thereof. It is preferable to have a larger bandgap energy than the semiconductor light emitting layer 23.

Note that the semiconductor light emitting layer 23 is an electron transport layer in the first light emitting element, but need not be an electron transport layer in the present light emitting element. Further, the n-side electrode 25 does not necessarily need to be formed on the entire surface of the electron transport layer 36.

This light emitting element can be manufactured in the same manner as the first light emitting element. Note that the electron transport layer 36 is
It can be formed in the same manner as the hole transport layer 22.
This light emitting element operates in the same manner as the first light emitting element except that light emission occurs in almost the entire semiconductor light emitting layer 23. Further, this light emitting element is used in the same manner as the first light emitting element, and the same effect can be obtained.

[0066]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Further, specific embodiments of the present invention will be described in detail with reference to the drawings. In the following example,
With reference to FIG. 3 used in the above embodiment, the description will be given with the same reference numerals.

(Embodiment 1) First, length 20 mm, width 20 m
A substrate 21 made of sapphire having a crystal lattice c-plane exposed on the surface having a dimension of m and a height of 1 mm was prepared, washed with a neutral detergent, washed with water, and further ultrasonically washed with an organic solvent. .

Next, the cleaned substrate 21 is transported into the MOCVD apparatus, and the substrate 21 is vaporized at a substrate temperature of 1050 ° C. while supplying hydrogen gas (H ₂ ) at a flow rate of ₂ dm ³ / min. Phase etching increased the surface roughness of the substrate.

Subsequently, after the temperature of the substrate 21 is set to 1000 ° C., hydrogen gas is supplied at 20 dm ³ while maintaining the substrate temperature.
/ Min, ammonia gas (NH ₃ ) is 10 dm ³ / m
in, trimethylgallium at 1.8 × 10 ⁻⁴ mol /
Dimethylmagnesium gas diluted to 2.2 ppm with hydrogen gas and hydrogen gas was supplied into the apparatus at a rate of 200 cm ³ / min for 30 minutes each, and a thickness of 5.0 μm and a carrier concentration of 7.8 were formed on the substrate 21. × 10 ¹⁹ c
A hole transport layer 22 of m- ³ single crystal p-type gallium nitride was formed.

Further, a zinc oxide microcrystal powder (manufactured by C-I Kasei Co., Ltd .; average particle diameter: 31 nm) produced by a gas phase method is ultrasonically dispersed in ethanol at a concentration of 10% by mass to prepare a coating solution. did. Thereafter, the coating solution was applied onto the hole transport layer 22 by spin coating at a rotational speed of 10 μm.
It was applied at 00 rpm and allowed to air dry. This coating process is repeated 5 times in total to form a coating layer, and then the coating is performed in an oxygen gas atmosphere at a concentration of 100% using an electric firing furnace.
The coating layer was heated at a temperature of 00 ° C. for 1 hour to sinter, thereby forming a semiconductor light emitting layer 23 of zinc oxide having a thickness of 2.5 μm.

After the formation of the semiconductor light emitting layer 23, a stripe-shaped resist pattern was formed on the semiconductor light emitting layer 23 corresponding to the position where the p-side electrode 24 was formed. The resist used was a positive resist for i-line exposure manufactured by Tokyo Ohka Kogyo Co., Ltd. Thereafter, using this resist pattern as a mask, the semiconductor light emitting layer 23 was selectively removed by a reactive ion etching method to expose a part of the hole transport layer 22.

After exposing a part of the hole transport layer 22, the resist pattern was removed, and a 500 nm-thick gold layer was electron-beam evaporated on almost the entire surface of the semiconductor light emitting layer 23 to form an n-side electrode 25. . The exposed hole transport layer 2
A nickel layer having a thickness of 10 nm, a platinum layer having a thickness of 100 nm, and a gold layer having a thickness of 500 nm were successively subjected to electron beam evaporation on the substrate 2 to form a p-side electrode 24. After that, 100% concentration
The heat treatment was performed at a temperature of 600 ° C. for 20 minutes in the nitrogen gas atmosphere described above to alloy the p-side electrode 24 and the n-side electrode 25. Thus, a light emitting device as shown in FIG. 3 was manufactured.

With respect to the light-emitting device thus obtained, room-temperature photoluminescence (PL) of the hole transport layer 22 and the semiconductor light-emitting layer 23 was measured.
(e.g., Cence) measurement. In room temperature photoluminescence measurement, H is used as the excitation light source.
Strong excitation was performed using an e-Cd laser (wavelength: 325 nm, output: 25 mW), and spectrum analysis was performed using a spectrophotometer (HR-320, manufactured by Jobin-Yvon). FIG. 5 shows the obtained PL emission spectrum. In FIG. 5, the vertical axis represents the light emission intensity, and the horizontal axis represents the wavelength (unit: nm).

As can be seen from FIG. 5, the semiconductor light emitting layer 23
Is about 380 nm, which is considered to be direct transition light emission.
The peak of PL emission intensity was observed. That is, it was confirmed that the semiconductor light emitting layer 23 had light emitting material characteristics. The semiconductor light emitting layer 23 has a wavelength of 500 n.
In the range of m to 600 nm, a peak of PL emission intensity considered to be due to oxygen deficiency was also observed. On the other hand, for the hole transport layer 22, no PL emission intensity peak was observed,
It turned out that it did not have the light emitting material characteristic.

As a comparative example with respect to the present embodiment, after forming a coating layer on the substrate 21 via the hole transport layer 22 and before sintering, the coating layer is compared with the semiconductor light emitting layer 23 of the present embodiment. Emission characteristics were evaluated in the same manner. FIG. 6 shows the PL emission spectrum of the obtained coating layer together with the PL emission spectrum of the semiconductor light emitting layer 23. The vertical and horizontal axes in FIG. 6 are the same as in FIG.

As can be seen from FIG. 6, as in the case of the semiconductor light emitting layer 23, a peak at a wavelength of 380 nm, which is considered to be direct transition light emission, and a peak at a wavelength of 500 to 600 nm, which is thought to be based on oxygen deficiency, are also observed in the coating layer. Was done. However, the PL emission intensity at a wavelength of 380 nm, which is considered to be direct transition emission, is stronger in the coating layer than in the semiconductor light emitting layer 23, and the wavelength 5 is considered to be based on oxygen deficiency.
The PL light emission intensity of 00 nm to 600 nm
The coating layer was weaker than No. 3. That is, it was found that the coating layer had few oxygen vacancies and the semiconductor light emitting layer 23 had many oxygen vacancies. Therefore, the semiconductor light emitting layer 23
It is presumed that sintering increases oxygen vacancies, thereby increasing electron transportability.

Further, for the semiconductor light emitting layer 23, a sample having a single layer structure was prepared on a substrate made of sapphire separately from the light emitting element, and a Hall effect measuring device (HL-5500C manufactured by Japan Bio-Rad Laboratories Co., Ltd.) was used. ) To evaluate the electrical characteristics. As a result, it was found that the semiconductor light emitting layer 23 had a specific resistance of 8.2 × 10 ³ Ωcm and had an electron transporting property. The electrical characteristics of the coating layer before sintering the sample were also evaluated by a four-terminal four-probe resistance meter (Loresta-GP, manufactured by Mitsubishi Chemical Corporation). 1 × 10 ⁷ Ω
cm or more, indicating no electron transportability. That is, it was found that the semiconductor light emitting layer 23 exhibited electron transportability (specific resistance of about 0.001 Ωcm to 10000 Ωcm) by sintering.

In addition, the semiconductor light emitting layer 23 was subjected to X-ray diffraction measurement (XRD; X-ray Diffrac).
Tion) and cross-sectional TEM (Transmission)
The crystal state was observed by nElectron Microscope). As a result, the semiconductor light emitting layer 2
No. 3 has a structure in which microcrystals were joined by sintering, and the crystal grain size was found to be about 40 nm on average from a TEM photograph.

Furthermore, the current-voltage characteristics (IV characteristics) of the obtained light emitting device were evaluated. FIG. 7 shows the result. In FIG. 7, the vertical axis represents current (unit: mA).
, And the horizontal axis represents the applied voltage (unit: V). Note that the polarity of the applied voltage (+ and-signs in the figure) is positive (+ sign) when the voltage is applied so as to have a positive potential on the p-side electrode 24 and a negative potential on the n-side electrode 25 of the light emitting element. did.

As can be seen from FIG. 7, in this light emitting device, a diode characteristic of a good rectifying action was recognized. That is, it was confirmed that in this light emitting element, a pn junction was formed by the hole transport layer 22 and the semiconductor light emitting layer 23.

In addition, simultaneously with the evaluation of the current-voltage characteristics described above, a room temperature EL (Electroluminescence)
(nce) measurement. In the room temperature EL measurement, a collimator lens having a diameter of 5 mm is adhered to the back surface of the substrate 21 of the light emitting element (the surface on which the semiconductor light emitting layer 23 is not formed), and an optical fiber cable having an inner diameter of 1 mm is connected to the collimator lens. And a spectrophotometer (S200 manufactured by Ocean Optics, Inc.)
The spectrum was analyzed in 0). FIG. 8 shows the obtained EL emission spectrum. In FIG. 8, the vertical axis represents light emission intensity, and the horizontal axis represents wavelength (unit: nm). The applied voltage at the time of EL measurement is 10 V in forward voltage (polarity; + sign)
And

As can be seen from FIG. 8, in this light emitting device, a peak of EL emission at a wavelength of 400 nm, which is considered to be caused by direct transition of zinc oxide microcrystals in the semiconductor light emitting layer 23, was observed. That is, it was confirmed that this light-emitting element operates by a direct current and has a light-emitting characteristic of emitting ultraviolet light due to a direct transition at room temperature.

(Embodiment 2) First, length 20 mm, width 20 m
Substrate 21 made of synthetic quartz having dimensions of m and 1 mm in height
Was prepared, washed with a neutral detergent, washed with water, and further ultrasonically washed with an organic solvent.

Next, on this substrate 21, a thickness of 1.1 μm and a carrier concentration of 3.5 × 10
^A hole transport layer 22 of ¹⁶ cm ⁻³ of polycrystalline p-type aluminum nitride was formed. An ArF excimer laser film forming device (laser wavelength: 193 nm) manufactured by Lambda Physics was used as the PLD device.

FIG. 9 shows a schematic configuration of the PLD device. This PLD device includes a vacuum chamber 43 made of stainless steel to which a gas supply pipe 41 and a gas exhaust pipe 42 are respectively connected. Vacuum chamber 43
A substrate holder 44 on which the substrate 21 is placed;
Target mounting plate 46 for mounting the target 45
Are disposed so as to face each other.
Although FIG. 9 shows a case where one target mounting plate 46 is provided, a plurality of target mounting plates 46 may be provided. Target 4
5 can be irradiated with a pulse laser L through a laser entrance 47 by a pulse laser device (not shown) provided outside the vacuum chamber 43. Further, a heating unit (not shown) such as a heater is provided inside the vacuum chamber 43 so that the substrate 21 can be heated.

Here, using such a PLD device,
Specifically, the following operation was performed. First, the cleaned substrate 21 was placed on a substrate holder 44, and a target 45 made of an aluminum-magnesium alloy (AlMg alloy) was mounted on a target mounting plate 46.
The target 45 used had a composition of 99% by weight of aluminum, 1% by weight of magnesium, and a purity of 99.9% by weight or more, manufactured by Sumitomo Metal Mining Co., Ltd.

Next, the gas in the vacuum chamber 43 is evacuated from the gas exhaust pipe 42, and 2.
The pressure was reduced to about 7 × 10 ⁻⁵ Pa. Subsequently, the substrate 21 is heated to 500 ° C. by a heater (not shown),
While maintaining the substrate temperature, 6.7 Pa of nitrogen gas having a concentration of 100% was introduced into the vacuum chamber 43 through the gas supply pipe 41.
The pressure was supplied until a moderate pressure was reached. Thereafter, the target 45 was irradiated with a pulse laser at an energy density of 200 mJ / cm ² , and the hole transport layer 22 was formed by reactive laser ablation D.

After the hole transport layer 22 was formed in this manner, a 2.4 μm thick semiconductor light emitting layer 23 made of zinc oxide was formed in the same manner as in the first embodiment. Thereafter, as in the first embodiment, the p-side electrode 24 and the n-side electrode
Each of the side electrodes 25 was formed, and alloying was performed by heating to produce a light emitting device as shown in FIG. However, in forming the p-side electrode 24, the thickness of the nickel layer was set to 50 nm. The heat treatment time for alloying was set to 60 minutes.

For the obtained light emitting device, evaluation of the light emitting characteristics of the hole transport layer 22 and the semiconductor light emitting layer 23, observation of the crystal state of the semiconductor light emitting layer 23, evaluation of the current-voltage characteristics of the device, and When the light emission characteristics of the device were evaluated, the same results as in Example 1 were obtained. That is, it was confirmed that high characteristics can be obtained regardless of the form, whether the hole transport layer 22 is made of single crystal or polycrystal.

Example 3 When forming the semiconductor light emitting layer 23, an ArF excimer laser apparatus (manufactured by Lambda Physics, laser wavelength: 193 nm) was used instead of the electric firing furnace.
A light emitting device was manufactured in the same manner as in Example 1 except that the coating layer was heated and sintered by irradiating a laser beam at an energy density of 60 mJ / cm ² .

For the obtained light emitting device, evaluation of the light emitting characteristics of the hole transport layer 22 and the semiconductor light emitting layer 23, evaluation of the electric characteristics of the semiconductor light emitting layer 23, and observation of the crystal state of the semiconductor light emitting layer 23 were performed in the same manner as in Example 1. When the current-voltage characteristics of the device and the light emission characteristics of the device were evaluated, the same results as in Example 1 were obtained. That is, it was confirmed that the same semiconductor light emitting layer 23 as that obtained by heating in an electric firing furnace was obtained by laser annealing.

(Examples 4 and 5) In Example 4, microcrystalline powder of titanium oxide (manufactured by C-I Kasei Corporation; average particle size: 30 nm) was used instead of microcrystalline powder of zinc oxide.
In the semiconductor light emitting layer 2, fine crystal powder of iron oxide (Fe ₂ O ₃ ) (manufactured by C-I Kasei Co., Ltd .; average particle diameter: 21 nm) is used.
Light emitting devices were manufactured in the same manner as in Example 1 except that No. 3 was formed.

With respect to the obtained light emitting devices of Examples 4 and 5, evaluation of the light emitting characteristics of the hole transport layer 22 and the semiconductor light emitting layer 23, evaluation of the electric characteristics of the semiconductor light emitting layer 23, and evaluation of the semiconductor light emitting layer were performed in the same manner as in Example 1. Observation of the crystal state of 23, evaluation of the current-voltage characteristics of the device, and evaluation of the light emission characteristics of the device were performed. As a result, the same results as in Example 1 were obtained. In the semiconductor light emitting layers 23 of Examples 4 and 5, the peak of the PL light emission intensity was observed at the visible light wavelength. The specific resistance of the semiconductor light emitting layer 23 was 9.1 × 10 ³ Ωcm in Example 4, and 9.8 × 10 ³ Ωcm in Example 5. By the way, the specific resistance of the coating layer before sintering them is one of the measurement limit values.
× 10 ⁷ Ωcm or more. That is, it was confirmed that the semiconductor light emitting layer 23 can be constituted by other oxides.

Although the present invention has been described with reference to the embodiments and examples, the present invention is not limited to the above-described embodiments and examples, and can be variously modified. For example, in the above embodiment, the case has been described where the microcrystals in the fine particle sintered body 10 are made of an oxide or a nitride, but they may be made of another semiconductor material. For example, at least one selected from the group consisting of zinc, magnesium (Mg), cadmium (Cd), manganese (Mn), mercury (Hg), and beryllium (Be).
Other II-VI compounds containing a Group 2 element of the species and at least one Group 6 element selected from the group consisting of oxygen (O), selenium (Se), sulfur (S) and tellurium (Te) A semiconductor or at least one group III element selected from the group consisting of boron, aluminum, gallium and indium, and nitrogen (N), phosphorus (P), arsenic (A
s), antimony (Sb) and bismuth (Bi), and may be made of another group III-V compound semiconductor containing at least one group V element selected from the group consisting of:

Further, in the above-described embodiment and the above-described embodiment, the case where the semiconductor light emitting layer 23 is constituted by the fine particle sintered body 10 containing the fine crystal made of oxide is described. It may be constituted by a fine particle sintered body, or may be constituted by a fine particle sintered body containing microcrystals made of other semiconductor materials described above.

Further, in the above-described embodiment, specific examples of materials constituting the hole transport layer 22 and the electron transport layer 36 have been described. However, they may be composed of other materials. . In addition, the material which comprises the hole transport layer 22 and the electron transport layer 36 is not limited to an inorganic material, but may be an organic material.

In addition, in the above embodiment, when the hole transport layer 22 and the semiconductor light emitting layer 23 are sequentially laminated on the substrate 21 or the hole transport layer 22, the semiconductor light emitting layer 23 and the electron transport layer 36 are sequentially laminated on the substrate 21. Although the case of stacking has been described, a semiconductor light emitting layer and a hole transport layer may be sequentially stacked on a substrate, or an electron transport layer, a semiconductor light emitting layer, and a hole transport layer may be sequentially stacked on a substrate.

Furthermore, in the above embodiment, the first conductivity type layer is a hole transport layer and the second conductivity type layer is an electron transport layer. However, the first conductivity type layer is an electron transport layer, and the second conductivity type layer is an electron transport layer. The mold layer may be a hole transport layer.

In addition, in the above embodiment, a specific light emitting diode is described as an example of the light emitting element. However, the present invention can be widely applied to light emitting diodes having other configurations. For example, the hole transport layer or the electron transport layer may have a stacked structure including a plurality of layers. Further, for example, a first electrode and a second electrode may be provided on the semiconductor light emitting layer made of the fine particle sintered body 10. Furthermore, the present invention can be applied to other light emitting elements such as a laser diode. That is, the present invention can be widely applied to a light emitting device having a semiconductor light emitting layer made of the fine particle sintered body 10.

[0100]

As described above, according to the light emitting device according to any one of the first to twenty-fourth aspects, the fine particle containing semiconductor microcrystals is formed by a fine particle sintered body joined by a sintered region. According to the method for manufacturing a light emitting device according to any one of claims 25 to 49, since the semiconductor light emitting layer is provided, a fine particle sintered body obtained by sintering fine particles containing semiconductor microcrystals. As a result, the semiconductor light emitting layer is formed, so that the carrier transporting property in the semiconductor light emitting layer can be ensured, and the semiconductor light emitting layer can be easily operated with a low voltage DC current. Therefore, there is an effect that the display device can be used as a display element of an electric product used outdoors such as a mobile phone without requiring a complicated and expensive drive circuit.

Further, the substrate can be formed on an arbitrary substrate, and it is not necessary to use a substrate having excellent heat resistance as compared with the case where the substrate is formed by an epitaxial growth method such as MOCVD. Therefore, the material of the substrate can be arbitrarily selected, and the area of the substrate can be increased, and the production cost can be reduced. Further, there is an effect that it is not necessary to precisely control the crystal system and the lattice constant in forming the semiconductor light emitting layer, and the semiconductor light emitting layer can be easily manufactured.

In particular, claim 5, claim 17, and claim 27
Alternatively, according to the light emitting device of any one of claims 39, since the microcrystal is made of zinc oxide,
Ultraviolet light can be easily emitted at room temperature. Therefore, when used as a phosphor excitation light source, there is an effect that it can be applied to a display, a lighting fixture, and the like. For example, a large-sized flat display can be realized by using an image display element based on the coloring of a phosphor as an excitation energy source in place of an electron gun of a CRT or a cold cathode of an FED.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram illustrating a configuration of a fine particle sintered body used for a light emitting device according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram illustrating a fine particle aggregate before sintering.

FIG. 3A is a plan view illustrating a configuration example of a first light-emitting element according to an embodiment of the present invention, and FIG. 3B is a cross-sectional view taken along line II of FIG. is there.

FIG. 4A is a plan view illustrating a configuration example of a second light-emitting element according to an embodiment of the present invention, and FIG. 4B is a cross-sectional view taken along line II-II of FIG. is there.

FIG. 5 is a PL emission spectrum of the semiconductor light emitting layer and the hole transport layer according to Example 1 of the present invention.

FIG. 6 shows PL emission spectra of a semiconductor light emitting layer according to Example 1 of the present invention and a coating layer according to a comparative example.

FIG. 7 is a characteristic diagram illustrating current-voltage characteristics (IV characteristics) of the light emitting device according to Example 1 of the present invention.

FIG. 8 is an EL emission spectrum of the light emitting device according to Example 1 of the present invention.

FIG. 9 is a cross-sectional view illustrating a schematic configuration of a pulse laser film forming apparatus used when forming a hole transport layer in Example 2 of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Fine particle sintered body, 11 ... Fine particle, 11a ... Sintered area, 21 ... Substrate, 22 ... Hole transport layer (1st conductivity type layer), 23 ... Semiconductor light emitting layer, 24 ... p side electrode (1st electrode) ), 25 ... n-side electrode (second electrode), 36 ... electron transport layer (second conductivity type layer), 41 ... gas supply pipe, 42 ... gas exhaust pipe, 43 ... vacuum chamber, 44 ... substrate holder, 4
5 target, 46 target mounting plate, 47 target
Laser entrance, L: pulsed laser, D: ablation.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shigeru Kojima 6-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony Corporation F-term (reference) 5F041 AA31 CA04 CA05 CA34 CA40 CA41 CA46 CA57 CA65 CA73 CA77 CA83 5F073 AA75 CA22 CA24 CB19 CB22 DA05 DA17 DA35 EA29

Claims (49)

[Claims] A hole transporting layer; a semiconductor light emitting layer formed on one surface side of the hole transporting layer, the semiconductor light emitting layer comprising a fine particle sintered body in which fine particles containing semiconductor microcrystals are joined by a sintering region; A light-emitting element comprising: a first electrode electrically connected to a layer; and a second electrode electrically connected to the semiconductor light-emitting layer. 2. The light emitting device according to claim 1, wherein the semiconductor light emitting layer has an electron transport function. 3. The light emitting device according to claim 1, wherein the crystal grain size of the microcrystal in the fine particle sintered body is 100 nm or less. 4. The microcrystal in the fine particle sintered body is an oxide containing at least one of a group consisting of zinc (Zn), titanium (Ti) and iron (Fe), or a nitride of a 3B group element. The light emitting device according to claim 1, wherein the light emitting device comprises: 5. The light emitting device according to claim 1, wherein the microcrystals in the fine particle sintered body are made of zinc oxide (ZnO). 6. The light emitting device according to claim 1, wherein the hole transport layer has a larger bandgap energy than the semiconductor light emitting layer. 7. The light emitting device according to claim 1, wherein the hole transport layer is made of a nitride of a group 3B element containing an acceptor impurity. 8. The nitride of a Group 3B element includes boron nitride (BN), aluminum nitride (AlN), gallium nitride (GaN), and aluminum-gallium nitride mixed crystal (A).
The light-emitting device according to claim 7, wherein the light-emitting device is at least one member of the group consisting of 1GaN). 9. The light emitting device according to claim 7, wherein said acceptor impurity is magnesium (Mg). 10. The light emitting device according to claim 1, wherein the hole transport layer is formed of a single crystal, a polycrystal, an amorphous material, a fine particle, or a composite thereof. 11. The light emitting device according to claim 1, wherein the first electrode and the second electrode contain at least gold (Au). 12. The light emitting device according to claim 1, wherein the first electrode has a structure in which a nickel layer, a platinum layer, and a gold layer are stacked. 13. The method according to claim 1, wherein the first electrode and the second electrode are alloyed.
The light-emitting element according to any one of the preceding claims. 14. A fine particle sintered body formed between the hole transport layer, the electron transport layer, and the hole transport layer and the electron transport layer, wherein the fine particles containing semiconductor microcrystals are joined by a sintered region. A semiconductor light emitting layer, a first electrode electrically connected to the hole transport layer, and a second electrode electrically connected to the electron transport layer. Light emitting element. 15. The light emitting device according to claim 14, wherein a crystal grain size of the microcrystal in the fine particle sintered body is 100 nm or less. 16. The microcrystal in the fine particle sintered body,
Oxide containing at least one member of the group consisting of zinc (Zn), titanium (Ti) and iron (Fe), or 3B
The light emitting device according to claim 14, wherein the light emitting device is made of a nitride of a group III element. 17. The microcrystal in the fine particle sintered body,
The light emitting device according to claim 14, wherein the light emitting device is made of zinc oxide (ZnO). 18. The light emitting device according to claim 14, wherein the hole transport layer and the electron transport layer have a larger bandgap energy than the semiconductor light emitting layer. 19. The light emitting device according to claim 14, wherein the hole transport layer is made of a nitride of a group 3B element containing an acceptor impurity. 20. The light emitting device according to claim 19, wherein the acceptor impurity is magnesium (Mg). 21. The light emitting device according to claim 14, wherein the electron transport layer is made of a nitride of a Group 3B element containing a donor impurity. 22. The donor impurity is silicon (Si).
22. The light emitting device according to claim 21, wherein 23. The method according to claim 14, wherein the hole transport layer and the electron transport layer are formed of a single crystal, a polycrystal, an amorphous material, a fine particle, or a composite thereof. Light emitting element. 24. A semiconductor light emitting layer comprising a fine particle sintered body in which fine particles containing semiconductor microcrystals are joined by a sintered region, a first electrode and a second electrode electrically connected to the semiconductor light emitting layer, respectively. A light emitting device comprising: 25. A step of forming a hole transport layer on a substrate, and a step of forming a semiconductor light emitting layer on the hole transport layer by a fine particle sintered body obtained by sintering fine particles containing semiconductor microcrystals. A method for manufacturing a light emitting device, comprising: 26. The microcrystal is formed of an oxide containing at least one selected from the group consisting of zinc (Zn), titanium (Ti) and iron (Fe), or a nitride of a Group 3B element. The method for manufacturing a light emitting device according to claim 25, wherein 27. The method according to claim 25, wherein the microcrystal is formed of zinc oxide (ZnO). 28. The method according to claim 25, wherein the fine particles are sintered by heat treatment or irradiation with an energy beam. 29. The fine particles are sintered by irradiating an excimer laser beam.
9. The method for manufacturing a light emitting device according to item 8. 30. XeCl, XeF, XeBr, Kr
F, KrCl, method of manufacturing the light emitting device according to claim 29, wherein the sintering the fine particles by irradiating the excimer laser beam oscillated by using an ArF or F _2. 31. The method according to claim 25, wherein the fine particles are sintered in an oxygen-containing atmosphere or a nitrogen-containing atmosphere. 32. The content ratio of oxygen or nitrogen is 60 mol.
The method for manufacturing a light emitting device according to claim 25, wherein the fine particles are sintered in a gas atmosphere of not less than%. 33. The method for manufacturing a light emitting device according to claim 25, wherein a coating solution in which the fine particles are dispersed in a solution is applied on the hole transport layer, and then dried and sintered. 34. The method according to claim 33, wherein an organic solvent containing at least one organic compound having at least one hydroxyl group is used as the solution. 35. The method according to claim 34, wherein the organic compound is selected from alcohols and derivatives thereof, phenol and cresol. 36. A spin coating method, a dip coating method,
The method for manufacturing a light emitting device according to claim 33, wherein the coating solution is applied using a spray coating method, a roll coating method, a meniscus coating method, a bar coating method, a curtain flow coating method, or a bead coating method. 37. A step of forming a hole transport layer on a substrate, and a step of forming a semiconductor light emitting layer on the hole transport layer by a fine particle sintered body obtained by sintering fine particles containing semiconductor microcrystals. Forming an electron transport layer on the semiconductor light emitting layer. 38. The microcrystal is formed of an oxide containing at least one selected from the group consisting of zinc (Zn), titanium (Ti) and iron (Fe), or a nitride of a Group 3B element. The method for manufacturing a light emitting device according to claim 37, wherein 39. The method according to claim 37, wherein the microcrystal is formed of zinc oxide (ZnO). 40. The method according to claim 37, wherein the fine particles are sintered by heat treatment or irradiation with an energy beam. 41. The fine particles are sintered by irradiating an excimer laser beam.
0. A method for manufacturing a light-emitting element according to item 0. 42. XeCl, XeF, XeBr, Kr
F, KrCl, method of manufacturing the light emitting device according to claim 41, wherein the sintering the fine particles by irradiating the excimer laser beam oscillated by using an ArF or F _2. 43. The method according to claim 37, wherein the fine particles are sintered in an oxygen-containing atmosphere or a nitrogen-containing atmosphere. 44. The content ratio of oxygen or nitrogen is 60 mol.
The method for manufacturing a light emitting device according to claim 37, wherein the fine particles are sintered in a gas atmosphere of not less than%. 45. The method for manufacturing a light emitting device according to claim 37, wherein a coating solution in which the fine particles are dispersed in a solution is applied on the hole transport layer, and then dried and sintered. 46. The method according to claim 45, wherein an organic solvent containing at least one organic compound having at least one hydroxyl group is used as the solution. 47. The method according to claim 46, wherein the organic compound is selected from alcohols and derivatives thereof, phenol and cresol. 48. A spin coating method, a dip coating method,
46. The method according to claim 45, wherein the coating solution is applied using a spray coating method, a roll coating method, a meniscus coating method, a bar coating method, a curtain flow coating method, or a bead coating method. 49. A method for manufacturing a light-emitting device, comprising the step of forming a semiconductor light-emitting layer on a substrate using a fine particle sintered body obtained by sintering fine particles containing semiconductor microcrystals.