JP2008198614A - Light-emitting element and its manufacturing method, and light-emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting element capable of obtaining a light emission wavelength having large light emission intensity, and furthermore having a narrow half-value width. <P>SOLUTION: The light-emitting element 30 is equipped with a light-emitting layer 40 formed on a substrate 31. The light-emitting layer 40 is composed of quantum dots 41 as well as rare earth atoms 43 which is adhered to a surface of the quantum dots 41, and/or contained interior of the quantum dots 41. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light-emitting element, a manufacturing method thereof, and a light-emitting device. More specifically, the present invention is applicable to a light-emitting device such as a display or a backlight. The present invention relates to a light emitting element including rare earth atoms (including ions derived from rare earth atoms), a method for manufacturing the light emitting element, and a display device including the light emitting element.

  Currently, many light emitting devices such as light emitting diodes and semiconductor lasers are mainly made of III-V or II-VI group compound semiconductor materials such as GaAs. However, the production of these light emitting devices requires an expensive substrate such as a sapphire substrate, the production process is difficult due to the use of a gas such as arsine, and a large and expensive production facility. There are also problems such as high running costs.

  On the other hand, many semiconductor devices such as transistors and memory devices are currently produced from silicon-based materials such as silicon and silicon compound materials. Silicon resources are abundant, inexpensive, and have a low environmental impact. In particular, the high integration of LSIs using silicon-based materials has been steadily progressing since the 1970s, with the progress of miniaturization of individual transistors over a long period of about 30 years. Even now, DRAMs having a gigabit degree of integration have appeared on the market, and developments for achieving further performance improvements of future integrated circuits are continuing. In this way, silicon-based material is an excellent semiconductor device material that has accumulated know-how for microfabrication technology, has a low raw material price, and has a low environmental impact, but because the band structure is an indirect transition type, Since it is difficult to emit light, there has not been much research as a light-emitting device.

  Under such circumstances, in the indirect transition type silicon-based material, various studies and proposals for efficiently converting carriers into light like the direct transition type have been reported. One method is to localize the carrier wave function and use the quantum effect. According to this method, by using a quantum well structure such as a two-dimensional quantum well structure, a one-dimensional quantum well structure (quantum wire), or a zero-dimensional quantum well structure (quantum dot), electrons and holes that are carriers are microscopic regions. Can be trapped in. In the quantum dot, in particular, the state density of carriers can be brought close to a delta function state by localizing electrons and holes in a zero-dimensional manner, and the quantum of the wave function of the carrier according to the size of the carrier confinement region. Occurs and energy takes discrete values. By controlling the confinement method and the size of the carrier confinement region (quantum dot), the band edge emission recombination efficiency can be improved.

  In fact, research on III-V compound semiconductor materials is underway, and many new properties and properties that exceed conventional properties have been identified (for example, Tatsuya Fukuda, Jun Tatebayashi, Masao Nishioka, Yasuhiko Arakawa). "Refer to the 51st (Spring 2004) Applied Physics-related Joint Lecture 28a-ZB-8, 2004", "Control of emission wavelength of InAs / GaAs quantum dots using InGaAs strain relaxation layer".

With respect to silicon-based materials, research on quantum dots (for example, nanocrystals) made of semiconductor materials such as Si, Ge, and Si—Ge has been conducted. It has been reported that when these quantum dots are formed in an insulator having a large band gap such as SiO _x and excited with light such as a laser, relatively strong light emission occurs (for example, Hiroshi Kunii, Koichi Shinoda, Keisuke Sato, Kenji Hiraguri, Mitseo Iwase, Tomio Izumi, “Correlation between Si concentration and nanosilicon size in amorphous SiO _x film” 51st (Spring 2004) Joint Lecture on Applied Physics 28p-P6-3 (See 2004). In addition, when an electronic device is made to function by current injection, it has been reported that the device can be driven at a low voltage by forming a nanocrystal in an insulator having a large band gap such as SiO _x . However, there are still few studies and proposals on the structure of light emitting devices using silicon-based materials.

  Conventionally, rare earth atoms added to semiconductor materials are known to emit sharp infrared light or visible light due to intra-shell transitions (for example, Tatsuo Tashiro, Satoshi Koyanagi, Keiichi Aiso, Tanaka) (See Kanni, Shu Namiki, “Development of High-Power Optical Amplifiers”, Furukawa Electric Time Report No. 104, p. 59, July 1999). It is known that the emission wavelength and the half-value width of such rare earth atoms are almost independent of the semiconductor material and temperature and show a constant value. In particular, among rare earth elements, erbium (Er) has a light emission wavelength of 1.55 μm, and the light emission wavelength of 1.55 μm is the minimum transmission loss wavelength of an optical fiber. Therefore, application of erbium light emission to optical fiber communication is expected. Has been.

  As described above, although research on light-emitting materials such as quantum dots and rare earth elements made of semiconductor materials has been reported, research and proposals on device structures to function effectively as light-emitting devices have not been sufficient. The current situation is not.

  In the display device, various flat display devices such as a liquid crystal display device (LCD) and a plasma display device (PDP) have been commercialized in place of the cathode ray tube (CRT) which has been the mainstream until now. Research and commercialization of cold cathode field emission display (FED), surface conduction electron emission display (SED), and organic electroluminescence (organic EL) display devices are in progress.

  As described above, various display devices have been manufactured and developed as flat display devices, but each has various problems in performance, power consumption, manufacturing cost, and the like.

  For example, in a liquid crystal display device (LCD), the direction of light is manipulated using a twisted arrangement of rod-like liquid crystal molecules, so that the viewing angle is narrower than that of a CRT, and light and dark unevenness and color unevenness. There is a problem that is likely to occur. At present, the narrowness of the viewing angle is being improved by in-plane switching technology, vertical alignment technology, multi-domain technology, and combinations thereof. However, it has a structure in which the light of the backlight is easily absorbed, a backlight having a higher light emission intensity is required, and there is a problem that power consumption tends to increase. There is also a problem of color depth. In the case of CRT, the amount of electrons that collide with the phosphor can be changed in an analog manner, so that infinite color and brightness can be expressed. On the other hand, in the case of a liquid crystal display device, the voltage applied to the liquid crystal cell is manipulated, and the amount of light transmitted through the backlight is adjusted stepwise, so that there is a problem that subtle color expression cannot be achieved. Furthermore, there is a problem that the response speed is slow. In the case of CRT, since the electron beam speed is high, there is almost no problem of response. However, in the case of a liquid crystal display device, a moving image is displayed by the actual movement of liquid crystal molecules, so a time lag occurs. Specifically, in the case of a liquid crystal display device driven by a passive matrix, the response is 150 milliseconds or more, and in the case of a standard active matrix drive liquid crystal display device suitable for moving image display, the response is about 40 milliseconds, In the case of MVA with the fastest response, there is a time lag of about 25 milliseconds. In addition, although there is an image that the power consumption is lower than that of CRT, with the improvement in functionality due to the improvement of viewing angle and response, etc., it is moving toward a structure that easily absorbs light and is currently emitted from the backlight. Only about 10% of the light is extracted on the surface of the liquid crystal display device, and power consumption is increasing. Furthermore, the manufacturing process is complicated, and a high-cost glass substrate is used for the substrate. Therefore, there is a problem that the price is higher than CRT and it is difficult to make it cheap in the future. .

  In addition, the organic EL display is expected in the future, but there are many problems at present in order to realize an increase in size. One of the major problems of organic EL displays is the problem of lifetime. Organic molecules such as a light emitting layer, a hole transport layer, and an electron transport layer constituting a light emitting element, and a magnesium alloy or calcium which is a cathode material for efficiently injecting electrons (that is, an electron injection barrier is low) There is a problem that it is weak against oxygen and moisture and reacts with oxygen and moisture to cause a dark spot and a dark spot on the display as well as a decrease in luminance. Although such problems have been improved, for large displays that require a long lifetime, the current situation is that the lifetime is not sufficient, and improvements to the elements themselves and technologies to block external factors are required.

Tatsuya Fukuda, Jun Tatebayashi, Masao Nishioka, Yasuhiko Arakawa, “Emission Wavelength Control of InAs / GaAs Quantum Dots Using InGaAs Strain Relaxation Layers” 51st (Spring 2004) Joint Lecture on Applied Physics 28a-ZB- 8, 2004 Hiroshi Kunii, Koichi Shinoda, Keisuke Sato, Kenji Hiraguri, Mitsuo Iwase, Tomio Izumi, “Correlation between Si concentration and nanosilicon size in amorphous SiOx film” 51st (Spring 2004) Joint Lecture on Applied Physics 28p -P6-3, 2004 Tatsuro Tashiro, Satoshi Koyanagi, Keiichi Aiso, Kanni Tanaka, Shu Namiki, "Development of High-Power Optical Amplifiers" Furukawa Electric Time Report No. 104 p. 59, July 1999

  It is known that the emission wavelength in a light-emitting device composed only of quantum dots (nanocrystals) usually shows a large half-value width of several tens to several hundreds of nanometers. It is currently difficult to increase the value.

  In addition, as described above, various current flat display devices have a narrow viewing angle, light and dark unevenness and color unevenness, a problem with color depth, a slow response speed, high manufacturing cost, and downsizing. However, there are various problems such as that it is difficult to extend the life, and that power consumption is large.

  Accordingly, an object of the present invention is to provide a light emitting element having a high emission intensity and capable of obtaining a light emission wavelength with a narrow half-value width, a method for manufacturing the light emitting element, and the light emitting element incorporating such a light emitting element. It is an object of the present invention to provide a light emitting device that can solve the problems of various flat display devices.

The light emitting device according to the first aspect of the present invention for achieving the above object is a light emitting device comprising a light emitting layer formed on a substrate,
The light emitting layer has a structure in which a first material layer, a quantum well layer, and a second material layer are stacked,
A rare earth atom is contained in at least one of the first material layer and the second material layer.

The light emitting device according to the first aspect of the present invention for achieving the above object is a light emitting device including a plurality of light emitting elements each including a light emitting layer formed on a substrate.
The light emitting layer constituting each light emitting element has a structure in which a first material layer, a quantum well layer, and a second material layer are laminated,
A rare earth atom is contained in at least one of the first material layer and the second material layer.

The method for manufacturing a light emitting device according to the first aspect of the present invention for achieving the above object has a structure in which a first material layer, a quantum well layer, and a second material layer are stacked on a substrate. And a method of manufacturing a light emitting element, wherein a light emitting layer containing a rare earth atom is formed in at least one of the first material layer and the second material layer,
Rare earth atoms are included by performing ion implantation on at least one of the first material layer and the second material layer.

In the method for manufacturing the light emitting device according to the first aspect of the present invention,
After forming the first material layer mainly composed of silicon on the substrate,
The first material layer is ion-implanted to include rare earth atoms,
After forming the quantum well layer on the first material layer,
Forming a second material layer mainly composed of silicon on the quantum well layer;
Rare earth atoms are included by ion-implanting the second material layer,
It is preferable.

In the method for manufacturing the light emitting device according to the first aspect of the present invention including the preferred embodiment described above, the concentration peak of the rare earth atoms in the thickness direction in the layer containing the rare earth atoms is From the interface of the well layer, it can be configured to perform ion implantation so that the energy transition by the Förster mechanism (Foerster mechanism) occurs. In this case, in the layer containing rare earth atoms, The concentration peak of rare earth atoms in the thickness direction is preferably located within a range of 1 × 10 ⁻⁸ m from the interface between the layer and the quantum well layer. Alternatively, in a layer containing rare earth atoms, a concentration peak of rare earth atoms in the thickness direction causes energy transition by the Dexter mechanism (also called Dexter mechanism or exchange mechanism) from the interface between the layer and the quantum well layer. In this case, in the layer containing rare earth atoms, the concentration peak of the rare earth atoms in the thickness direction of the layer and the quantum well layer can be set. It is preferably located within a range of 1 × 10 ⁻⁹ m from the interface. Alternatively, in the layer containing the rare earth atoms, the concentration peak of the rare earth atoms in the thickness direction is located within the range in which the energy transition through the photon occurs from the interface between the layer and the quantum well layer. It can be set as the structure which performs ion implantation.

The light emitting device according to the second aspect of the present invention for achieving the above object is a light emitting device comprising a light emitting layer formed on a substrate,
The light emitting layer is characterized by comprising quantum dots and rare earth atoms attached to the surface of the quantum dots and / or contained in the quantum dots.

A light emitting device according to a second aspect of the present invention for achieving the above object is a light emitting device including a plurality of light emitting elements each including a light emitting layer formed on a substrate.
The light emitting layer constituting each light emitting element is characterized by comprising a quantum dot and a rare earth atom attached to and / or contained in the surface of the quantum dot.

The method for manufacturing a light emitting device according to the second aspect of the present invention for achieving the above object is formed on a substrate, adhered to the surface of the quantum dot, and / or the quantum dot. A method of manufacturing a light emitting device including a light emitting layer composed of rare earth atoms contained in a dot,
The light emitting layer,
After forming quantum dots,
Diffusing rare earth atoms in the quantum dots and / or attaching rare earth atoms to the surface of the quantum dots;
After the product obtained by mixing the quantum dots and the silicon alkoxide is attached to the substrate, the product is annealed.
It is characterized by forming by.

In the method for manufacturing a light emitting device according to the second aspect of the present invention, the step of mixing the quantum dots and the silicon alkoxide to obtain a product includes mixing the quantum dots and the silicon alkoxide, Can be added as a catalyst to hydrolyze the silicon alkoxide. Here, without limitation, as a catalyst, there can be exemplified a configuration in which the addition of ammonium hydroxide (NH ₄ OH). The product obtained by mixing the quantum dots and the silicon alkoxide is a sol-like or gel-like product, and a structure in which this product is attached to the substrate for each light emitting device (adjacent each light emitting device is attached). A structure in which the substrate is adhered to the substrate in a spatially separated state.

Furthermore, in the method for manufacturing a light emitting device according to the second aspect of the present invention including the various preferred embodiments described above, tetramethoxysilane (Si (OCH ₃ ) ₄ ) or tetraethoxysilane ( Si (OC ₂ H ₅ ) ₄ ) can be exemplified.

  Furthermore, in the method for manufacturing a light emitting device according to the second aspect of the present invention including the various preferred embodiments described above, the annealing treatment is performed at 100 ° C. in an inert gas atmosphere composed of a rare gas or a nitrogen gas. It is desirable that the temperature is 1500 ° C or lower, preferably 100 ° C or higher and 1300 ° C or lower, more preferably 100 ° C or higher and 1200 ° C or lower. By performing such an annealing treatment, impurities such as water can be burned out and the rare earth ions can be activated.

  Moreover, in the manufacturing method of the light-emitting device according to the second aspect of the present invention including the above-described various preferred embodiments, the porous material obtained by anodizing the silicon semiconductor substrate is not limited. It is desirable to form quantum dots by subjecting the silicon semiconductor substrate to ultrasonic treatment in a solvent.

  Furthermore, in the method for manufacturing a light emitting device according to the second aspect of the present invention including the various preferred embodiments described above, the rare earth atoms are diffused into the quantum dots by ion implantation into the quantum dots. Alternatively, the rare earth atoms can be attached to the surface of the quantum dots by electroless plating, sputtering, or molecular beam epitaxy (MBE). Examples of a method for attaching a product obtained by mixing quantum dots and silicon alkoxide to a substrate include a screen printing method, a printing method using an inkjet method, and a dipping method.

The light emitting element according to the first aspect of the present invention, the light emitting device according to the first aspect of the present invention, or the method for manufacturing the light emitting element according to the first aspect of the present invention (hereinafter collectively referred to as the present invention). The quantum well layer in the first aspect of the invention may be referred to as a layer including a two-dimensional quantum well (so-called quantum well), a layer including a one-dimensional quantum well (so-called quantum wire), and a zero-dimensional quantum It means a layer containing wells (so-called quantum dots or nanocrystals). The thickness of the quantum well layer is 5 × 10 ⁻¹⁰ m (thickness of about one atom) to 1 × 10 ⁻⁸ m, preferably 5 × 10 ⁻¹⁰ m to 5 × 10 ⁻⁹ m. This is desirable from the viewpoint of improving luminous efficiency.

  In the first aspect of the present invention, the light emitting layer has a structure in which a first material layer, a quantum well layer, and a second material layer are stacked. In such a structure, the quantum well layer includes A structure in which the first material layer and / or the second material layer are randomly dispersed is also included, and a structure in which the first material layer, the quantum well layer, and the second material layer are stacked in layers is also included. In addition, a structure in which the quantum well layer is formed in an island shape in the boundary region between the first material layer and the second material layer is also included. In the structure in which the first material layer, the quantum well layer, and the second material layer are stacked in layers, it is included in the region of at least one of the first material layer and the second material layer in the vicinity of the quantum well layer. The rare earth atoms may be the same or different. Further, in the configuration in which both the first material layer and the second material layer contain rare earth atoms, the rare earth atoms contained in the first material layer and the rare earth atoms contained in the second material layer are the same kind of rare earth atoms. Alternatively, different rare earth atoms may be used.

  On the other hand, the light emitting element according to the second aspect of the present invention, the light emitting device according to the second aspect of the present invention, or the method for manufacturing the light emitting element according to the second aspect of the present invention (hereinafter collectively referred to as these). In some cases, the light emitting layer may have a single layer or a multi-layered structure. In the latter case, different rare earth elements may be used. A structure in which light-emitting layers containing atoms are stacked can also be used. In addition, the light emitting layer is composed of quantum dots and rare earth atoms attached to and / or contained inside the quantum dots. Specifically, the rare earth atoms are the surface of the quantum dots. Or attached to the inside of the quantum dot (diffused), or attached to the surface of the quantum dot and contained within the quantum dot. .

In the first aspect of the present invention, in the layer containing rare earth atoms, the concentration peak of the rare earth atoms in the thickness direction is caused by energy transition by the Forster mechanism from the interface between the layer and the quantum well layer. In this case, in the layer containing rare earth atoms, the concentration peak of the rare earth atoms in the thickness direction is 1 × 10 ⁻ from the interface between the layer and the quantum well layer. It is preferably located within the range of ⁸ m.

Alternatively, in the first aspect of the present invention, in the layer containing rare earth atoms, the concentration peak of the rare earth atoms in the thickness direction is caused by the energy of the Dexter mechanism from the interface between the layer and the quantum well layer. In this case, in the layer containing rare earth atoms, the concentration peak of the rare earth atoms in the thickness direction is 1 × from the interface between the layer and the quantum well layer. It is preferably located within the range of 10 ^-9 m.

  Alternatively, in the first aspect of the present invention, in the layer containing rare earth atoms, the concentration peak of the rare earth atoms in the thickness direction passes through the photon from the interface between the layer and the quantum well layer. It can be set as the structure located in the range where energy transition occurs.

  The light-emitting element according to the first aspect of the present invention including the various preferred embodiments described above, the light-emitting device according to the first aspect of the present invention, the method for manufacturing the light-emitting element according to the first aspect of the present invention, the present invention The light emitting element according to the second aspect of the invention, the light emitting device according to the second aspect of the present invention, or the method for manufacturing the light emitting element according to the second aspect of the present invention (hereinafter collectively referred to as the present invention). In some cases, the light-emitting element is an electroluminescence element, more specifically, a current injection type electroluminescence element (an electroluminescence element that emits light by directly flowing charge carriers from an electrode to a light-emitting layer) ) Or an intrinsic electroluminescence device (an electroluminescence device that emits light by exciting a light emitting layer in a dielectric with a strong external electric field) The light emitting device of the present invention, an electroluminescence display device, a current injection type electroluminescence display device, corresponding to the intrinsic electroluminescent display device. Alternatively, the light-emitting element can be a light-excitation light-emitting element or an electron beam-excitation light-emitting element. When the light-emitting element is a light-excited light-emitting element, the light-emitting element of the present invention may be combined with, for example, a light-emitting diode, or a light-emitting region of a plasma display device (PDP) (so-called fluorescence in a conventional plasma display device). The light emitting element of the present invention may be incorporated in a portion corresponding to the body layer. When the light-emitting element is a light-excited light-emitting element, the light-emitting device of the present invention corresponds to a display device including a light-emitting diode or a plasma display device (PDP). On the other hand, when the light emitting element is an electron beam excitation type light emitting element, a cold cathode field emission display (FED), a surface conduction electron emission display (SED), or a metal / insulating film / metal type element also called MIM element is used. The light-emitting element of the present invention may be incorporated in a light-emitting region (a portion corresponding to a so-called phosphor layer in these conventional display devices) constituting an anode panel in a display device provided. When the light emitting element is an electron beam excitation type light emitting element, the light emitting device of the present invention is a cold cathode field emission display (FED), surface conduction electron emission display (SED), or metal / insulating film also called MIM element. / Corresponds to a display device provided with a metal-type element.

Furthermore, in the first aspect of the present invention including the various preferable modes described above, the quantum well layer can be composed of silicon, germanium, or silicon-germanium, or In addition, the structure may be composed of a silicon-based oxide (SiO _x , 0 <X ≦ 2), or may be composed of a silicon-based nitride such as SiN, or a mixture of these materials. It can also be set as the structure which consists of. When the quantum well layer is composed of silicon, germanium, or silicon-germanium, the quantum well itself (that is, a so-called quantum well, a so-called quantum wire, a so-called quantum dot, or a nanocrystal; the same applies to the following description. Is made of silicon, germanium, or silicon-germanium, and the quantum well itself has a structure surrounded by, for example, a silicon-based oxide (SiO _x , 0 <X ≦ 2). Further, when the quantum well layer is composed of a silicon-based oxide, the quantum well itself is composed of a silicon-based oxide, and the quantum well itself is, for example, a silicon-based oxide having a higher oxygen content ( The structure is surrounded by SiO _x , 0 <X ≦ 2). Further, when the quantum well layer is made of silicon nitride, the quantum well itself is made of silicon nitride, and the quantum well itself is made of, for example, silicon oxide (SiO _x , 0 < The structure is surrounded by X ≦ 2).

  In the first aspect of the present invention including the various preferred embodiments described above, the layer containing rare earth atoms can be composed mainly of silicon. The layer containing atoms is preferably made of a silicon-based oxide.

  On the other hand, the light emitting element according to the second aspect of the present invention including the various preferred embodiments described above, the light emitting device according to the second aspect of the present invention, or the light emitting element according to the second aspect of the present invention. In the manufacturing method, the quantum dots are preferably made of silicon.

  In the present invention including the various preferred embodiments described above, at least eurobium (Eu) is included as the rare earth atom, or at least praseodymium (Pr) is included as the rare earth atom, or alternatively, as the rare earth atom. At least terbium (Tb) as a rare earth atom, or at least cerium (Ce) as a rare earth atom, or at least thulium (Tm) as a rare earth atom. ). Table 1 below shows the relationship between ions derived from rare earth atoms and the emission wavelength of the light-emitting element. In the present invention, the rare earth atom includes ions derived from the rare earth atom.

[Table 1]
Ion derived from rare earth atoms Light emission wavelength Pr ³⁺ 635 nm (red)
Eu ³⁺ 615nm (red)
Pr ³⁺ 605nm (red)
Er ³⁺ 570nm (orange)
Tb ³⁺ 545nm (green)
Ce ³⁺ 530nm (blue)
Tm ³⁺ 450nm (blue)

The rare earth elements are 15 kinds of 4f orbits from scandium (Sc) with atomic number 21 to yttrium (Y) with atomic number 39 and lanthanum (La) with atomic number 57 to lutetium (Lu) with atomic number 71. Since it is a group of transition series elements and belongs to group IIIB of the periodic table, generally trivalent is stable. Among these, 13 kinds of rare earth atoms from Ce ³⁺ (cerium: atomic number 58) to Yb ³⁺ (ytterbium: atomic number 70) have 1 to 13 4f electrons, and there is a difference in electron arrangement. Based on various energy levels. Since the electron transition energy between different energy levels corresponds to ultraviolet light, visible light, and infrared light, many rare earth atoms absorb and emit light at these wavelengths. That is, cerium (Ce) having an atomic number of 58 to ytterbium having an atomic number of 70 (Yb) having at least “4f electrons” can be used as the rare earth atom, and scandium (Sc) having an atomic number of 21 can be used. It is also possible to use yttrium (Y) having an atomic number of 39.

In the light emitting device according to the first aspect or the second aspect of the present invention including the various preferred embodiments described above, the first light emission that emits light of the first wavelength λ ₁ corresponding to red. Three types of light emission: an element, a second light emitting element that emits light of a _second wavelength λ ₂ corresponding to green, and a third light emitting element that emits light of a _third wavelength λ ₃ corresponding to blue One light emitting element unit is constituted by the element, and a plurality of light emitting element units can be provided. Alternatively, a first light emitting element that emits light having a _first wavelength λ ₁ corresponding to red, a second light emitting element that emits light having a _second wavelength λ ₂ corresponding to green, and a first light emitting element corresponding to blue. 4 types of light emitting elements, that is, a third light emitting element that emits light of a wavelength λ ₃ of 3 and a fourth light emitting element that emits light of a _fourth wavelength λ ₄ corresponding to other colors, One light emitting element unit is configured, and a plurality of light emitting element units can be provided. In addition, you may comprise one light emitting element unit by five or more types of light emitting elements.

In the present invention, a silicon semiconductor substrate can be exemplified as the substrate. However, the substrate is not limited to such a substrate, and other semiconductor substrates having a surface formed with an insulating film, GaAs substrate, GaN substrate, semi-insulating Substrate, semi-insulating substrate with insulating film formed on the surface, insulating substrate, insulating substrate with insulating film formed on the surface, quartz substrate, quartz substrate with insulating film formed on the surface, glass substrate, surface A glass substrate on which an insulating film is formed can be given, and an insulating layer or a sealing layer may correspond to a base depending on a target in which a light emitting element is formed. Here, as a glass substrate, high strain point glass, soda glass (Na ₂ O · CaO · SiO ₂ ), borosilicate glass (Na ₂ O · B ₂ O ₃ · SiO ₂ ), forsterite (2MgO · SiO ₂ ) Lead glass (Na ₂ O · PbO · SiO ₂ ) can be exemplified.

  In the present invention, the measurement of the concentration peak of rare earth atoms in the thickness direction, the measurement of the amount (concentration) of rare earth atoms attached to the surface of the quantum dots and / or contained within the quantum dots, Ratherford backscatter (RBS) measurements.

  The light-emitting device of the present invention can be applied not only to the various display devices described above but also to a lighting device including a backlight (for example, used for a liquid crystal display device). In addition, the light-emitting element of the present invention can be used as an alternative to a phosphor, and in some cases, the light-emitting device of the present invention can be used as an alternative to a display device having a conventional phosphor. Is possible.

  In the present invention, since the light emitting layer is composed of a quantum well layer and a rare earth atom, or a quantum dot and a rare earth atom, for example, conventional light emission in which a rare earth atom is simply dispersed in a silicon oxide film as an insulator. Compared with the device, a large current can be passed at a lower voltage, and it is possible to obtain an emission wavelength with high emission intensity and a narrow half width. This is because carriers are trapped in the quantum well layer or quantum dot and the energy of the carrier is confined. At this time, if rare earth atoms exist in the vicinity of the quantum well layer or quantum dot, the quantum well layer or quantum dot It is considered that the energy of the trapped carrier is transferred to the rare earth atom (that is, energy transition occurs), and then light emission occurs due to the intrashell transition of the rare earth atom. In this case, a higher emission intensity can be obtained with lower power consumption than in the case where there is no quantum well layer or quantum dot and light emission is caused by the transition of rare earth atoms in the shell only by hot electrons. Furthermore, in the case of having a quantum well structure as compared with a light emitting layer made of only silicon oxide that is an insulator, the electric resistance of the light emitting layer is reduced, and the light emitting element can be driven at a low voltage. In addition, the light-emitting element is self-luminous, hardly affected by magnetism, and even when the display device is enlarged, there is no distortion, and it is possible to obtain a display device with a clear and high-quality image and a high viewing angle. Become. Furthermore, compared with the conventional thin display device, further weight reduction and thickness reduction can be realized, and further reduction in power consumption and cost can be achieved.

  In the first aspect of the present invention, the luminous efficiency can be improved by defining the position of the concentration peak of the rare earth atom in the thickness direction in the layer containing the rare earth atom. In the second aspect, the light emitting layer is composed of quantum dots and the rare earth atoms attached to the surface of the quantum dots and / or contained within the quantum dots, so that the light emission efficiency is improved. be able to.

  In the method for manufacturing a light-emitting element according to the first aspect of the present invention, rare earth atoms are included by ion implantation in at least one of the first material layer and the second material layer. In the method for manufacturing a light emitting device according to the second aspect, a product (for example, a sol-like product or a product obtained by mixing a quantum dot containing a rare earth atom (including an attached aspect) and silicon alkoxide is used. Gel product) is attached to a predetermined position of the substrate, so that each light-emitting element, that is, a light-emitting element that emits a different color can be easily formed in a desired region. A light emitting element can be formed with high accuracy. In particular, in the method for manufacturing a light-emitting device according to the second aspect of the present invention, it is possible to form a light-emitting layer with lower energy consumption than in a conventional vapor phase process, and in the product adhesion step, It is possible to use an inexpensive screen printing method, ink jet method, or dipping method.

In the present invention, if a light emitting element is made of a silicon-based material, there is an advantage that the composition is stable compared to other materials. Furthermore, silicon-based materials are abundant in resources, so the price of raw materials is low, the environmental impact is small, they are harmless as waste, and the melting point is high so that they can sufficiently withstand high-temperature processing in production. is there. In addition, if a silicon semiconductor substrate is used as the base, it is possible to manufacture a driving transistor and a light emitting element integrally, and the display device can be further reduced in weight and thickness, and on the transparent electrode. In addition, advanced manufacturing techniques such as low-temperature TFT technology for manufacturing transistors are not required, and the manufacturing process can be simplified. Furthermore, if a driving transistor is formed on a silicon semiconductor substrate corresponding to the base, the electron mobility is amorphous silicon (1 cm ² V ⁻¹ sec ⁻¹ ) or polysilicon (100 cm ² V ⁻¹ sec ⁻¹ ). Compared with 400 cm ² V ⁻¹ s ⁻¹ ), it becomes as high as about 600 cm ² V ⁻¹ s ⁻¹ , and it is possible to further improve the response speed.

  Hereinafter, the present invention will be described based on examples with reference to the drawings.

  Example 1 relates to a light emitting device according to the first aspect of the present invention and a method for manufacturing the light emitting element according to the first aspect of the present invention. In Example 1 and Examples 2 to 4 to be described later, the light emitting element is a photoluminescence (PL) light emitting element.

A schematic partial cross-sectional view of the light-emitting element of Example 1 is shown in FIG. The light emitting element 10 of Example 1 includes a light emitting layer 20 formed on a substrate 11 (corresponding to a base) made of a silicon semiconductor substrate. The light emitting layer 20 has a structure in which a first material layer 21, a quantum well layer 24, and a second material layer 22 are stacked in this order. The first material layer 21 and the second material layer 22 are mainly composed of silicon, specifically made of a silicon-based oxide, more specifically silicon oxide (SiO ₂ ), and have a thickness of about 200 nm. The quantum well layer 24 is made of, for example, silicon (Si), germanium (Ge), or silicon-germanium (Si—Ge), or is made of a silicon-based oxide.

In at least one of the first material layer 21 and the second material layer 22 (both the first material layer 21 and the second material layer 22 in Example 1), the rare earth atoms 23 are more specifically provided. Specifically, ions derived from rare earth atoms are included. In the drawing, the rare earth atoms 23 or ions derived from the rare earth atoms are indicated by “x” marks. In the layer containing the rare earth atoms 23 (both the first material layer 21 and the second material layer 22 in Example 1), the concentration peak of the rare earth atoms in the thickness direction is the first material. It is located from the interface between the layer 21 and the quantum well layer 24 within a range where energy transition due to the Forster mechanism occurs (within a range where the energy of carriers confined in the quantum well layer can be transferred to the rare earth atoms), and the second From the interface between the material layer 22 and the quantum well layer 24, it is located within a range where energy transition by the Forster mechanism occurs. More specifically, in the layer containing rare earth atoms (both the first material layer 21 and the second material layer 22 in Example 1), the concentration peak of the rare earth atoms in the thickness direction is: located from the interface of the first material layer 21 and the quantum well layer 24 in the range of ^{1 × 10 -8 m (10nm)} , also, 1 × 10 ^-8 m from the interface of the second material layer 22 and the quantum well layer 24 It is located within the range of (10 nm). Alternatively, in the layer containing rare earth atoms (both the first material layer 21 and the second material layer 22 in Example 1), the concentration peak of the rare earth atoms in the thickness direction is the first material. It is located within the range where the energy transition via the photon occurs from the interface between the layer 21 and the quantum well layer 24, and within the range where the energy transition via the photon occurs from the interface between the second material layer 22 and the quantum well layer 24. . The rare earth atoms 23 are preferably introduced into both the first material layer 21 and the second material layer 22, but may be introduced into only one of the first material layer 21 and the second material layer 22. .

The rare earth atom 23 is eurobium (Eu). In this case, the light emitting element containing Eu ³⁺ emits red light (wavelength: 615 nm), or the rare earth atom 23 is praseodymium (Pr). In this case, Pr ^The light emitting element containing ³⁺ emits red light (wavelength: 605 nm), or the rare earth atom 23 is erbium (Er). In this case, the light emitting element containing Er ³⁺ emits orange light (wavelength: 570 nm). Alternatively, the rare earth atom 23 is terbium (Tb). In this case, the light emitting element containing Tb ³⁺ emits green light (wavelength: 545 nm). Alternatively, the rare earth atom 23 is cerium (Ce). in this case, the light-emitting element including Ce ³⁺ blue (wavelength: 530 nm) to emit Alternatively, the rare earth atom 23 is thulium (Tm), in this case, including the Tm ³⁺ Photoelement blue (wavelength: 450 nm) to emit. The rare earth atom 23 may be composed of a plurality of kinds of rare earth atoms as described above or other than that, and the emission color in this case is a mixture of specific emission colors emitted by the rare earth atom.

  Hereinafter, a method for manufacturing the light-emitting element of Example 1 will be described with reference to FIGS.

[Step-100]
A silicon substrate is prepared as the substrate 11 corresponding to the base. Then, based on a plasma enhanced chemical vapor deposition method (Plasma Enhanced Chemical Vapor Deposition method, PE-CVD method), a first material layer 21 containing silicon as a main component, more specifically, a thickness on the substrate 11. A first material layer 21 made of about 200 nm of SiO ₂ is formed.

[Step-110]
Next, rare earth atoms 23 are ion-implanted from the surface of the first material layer 21 by ion implantation (see FIG. 1A). That is, in the layer containing the rare earth atoms (first material layer 21), the concentration peak of the rare earth atoms in the thickness direction is observed from the interface between this layer (first material layer 21) and the quantum well layer 24. Ion implantation is performed so that the energy transition by the mechanism occurs. Alternatively, in the layer containing the rare earth atoms (first material layer 21), the concentration peak of the rare earth atoms in the thickness direction causes photons from the interface between the layer (first material layer 21) and the quantum well layer 24. Ion implantation is performed so as to be located within a range where energy transition occurs via. Specifically, the rare earth atom 23 (more specifically, derived from the rare earth atom so that the concentration peak of the rare earth atom 23 in the thickness direction is located within a range of 10 nm from the surface of the first material layer 21. Ions). For example, conditions for ion implantation into the first material layer 21 when the rare earth atom 23 is terbium (Tb) are illustrated in Table 2 below. After ion implantation, it is desirable to perform annealing treatment at a temperature of about 400 ° C. to 1200 ° C. for about 1 minute to 100 minutes to recover damage in the first material layer 21 by ion implantation. A desirable range of the dose is 1 × 10 ¹¹ atoms / cm ^{2 to} 1 × 10 ¹⁵ atoms / cm ² , preferably 1 × 10 ¹² atoms / cm ^{2 to} 1 × 10 ¹⁴ atoms / cm ^2. Can do. In addition, when ion implantation of europium (Eu), praseodymium (Pr), erbium (Er), cerium (Ce), and thulium (Tm) is performed, ions derived from these rare earth atoms are ion-implanted. The optimum acceleration energy and dose amount may be determined based on various tests, and ion implantation may be performed based on the determination.

[Table 2]
Acceleration energy: 10 keV
Ion species: Tb ³⁺
Dose amount: 1 × 10 ¹³ atoms / cm ²

[Step-120]
Thereafter, a quantum well layer 24 made of, for example, silicon (Si) and having a thickness of 10 nm is formed on the first material layer 21 based on, for example, the PE-CVD method (see FIG. 1B). Specifically, for example, under the conditions of a substrate temperature of 420 ° C., a SiH ₄ flow rate of 50 sccm, an Ar flow rate of 1000 sccm, a pressure of 5.3 × 10 ² Pa (4 Torr), an RF power of 250 W, and a gap of 14 mm, the quantum well layer 24 can be formed. Alternatively, the quantum well layer 24 can be formed by a sputtering method. Specifically, for example, the quantum well layer 24 can be formed by sputtering an Si target with argon plasma at an RF power of 500 W under an Ar flow rate of 20 sccm and a pressure of 1 × 10 ⁻⁴ Pa.

Instead of forming the quantum well layer 24 made of silicon (Si), a quantum well layer 24 made of germanium (Ge) may be formed, or the quantum well layer 24 made of silicon-germanium (Si-Ge). The quantum well layer 24 made of a silicon-based oxide may be formed. Specifically, the quantum well layer 24 made of a silicon-based oxide has, for example, a substrate temperature of 400 ° C., an SiH ₄ flow rate of 100 sccm, an N ₂ O flow rate of 2000 sccm, and a pressure of 3.3 × 10 ² Pa (2.5 Torr). The film can be formed by the CVD method under the conditions of RF power 150 to 300 W and gap 14 mm.

[Step-130]
Next, a second material layer 22 mainly composed of silicon, more specifically, a second material layer 22 made of SiO ₂ having a thickness of about 200 nm is formed on the quantum well layer 24 by, for example, PE-CVD. Form.

[Step-140]
Thereafter, rare earth atoms 23 are ion-implanted from the surface of the second material layer 22 by ion implantation (see FIG. 1C). That is, in the layer containing the rare earth atoms (second material layer 22), the concentration peak of the rare earth atoms in the thickness direction is observed from the interface between this layer (second material layer 22) and the quantum well layer 24. Ion implantation is performed so that the energy transition by the mechanism occurs. Alternatively, in the layer containing the rare earth atoms (second material layer 22), the concentration peak of the rare earth atoms in the thickness direction causes photons from the interface between the layer (second material layer 22) and the quantum well layer 24. Ion implantation is performed so as to be located within a range where energy transition occurs via. Specifically, the concentration peak of the rare earth atoms 23 in the thickness direction is located within the range of 10 nm from the interface between the quantum well layer 24 and the second material layer 22 to the inside of the second material layer 22 (in other words, The rare earth atoms 23 (more specifically, ions derived from the rare earth atoms) are ion-implanted so that the second material layer 22 is located at a depth of 190 nm from the surface of the second material layer 22. For example, conditions for ion implantation into the second material layer 22 when the rare earth atom 23 is terbium (Tb) are illustrated in Table 3 below. After the ion implantation, it is desirable to perform an annealing process at a temperature of about 400 ° C. to 1300 ° C. for about 1 to 100 minutes to recover damage in the first material layer 21 by the ion implantation. A desirable range of the dose is 1 × 10 ¹¹ atoms / cm ^{2 to} 1 × 10 ¹⁵ atoms / cm ² , preferably 1 × 10 ¹² atoms / cm ^{2 to} 1 × 10 ¹⁴ atoms / cm ^2. Can do. In addition, when ion implantation of europium (Eu), praseodymium (Pr), erbium (Er), cerium (Ce), and thulium (Tm) is performed, ions derived from these rare earth atoms are ion-implanted. The optimum acceleration energy and dose amount may be determined based on various tests, and ion implantation may be performed based on the determination.

[Table 3]
Acceleration energy: 600 keV
Ion species: Tb ³⁺
Dose amount: 1 × 10 ¹³ atoms / cm ²

  In [Step-110], instead of the combination of the PE-CVD method and the ion implantation method, the first material layer 21 is formed, the first material layer 21 is formed, and the rare earth atoms 23 are introduced by the sputtering method. Furthermore, the first material layer 21 may be formed. Similarly, in [Step-140], formation of the second material layer 22, formation of the second material layer 22, introduction of the rare earth atoms 23, and formation of the second material layer 22 are performed by sputtering. You may go.

Thus, in Example 1, the first material layer 21 made of SiO ₂ and having a thickness of 200 nm is formed on the substrate 11, and the first material layer 21 having the thickness of 10 nm made of silicon (Si) is formed. A quantum well layer 24 is formed, a second material layer 22 having a thickness of 200 nm made of SiO ₂ is formed on the quantum well layer 24, and terbium ions (introduced into the first material layer 21 and the second material layer 22 ( The light emitting element 10 in which the concentration peak in the thickness direction of (Tb ³⁺ ) was located at a position about 10 nm away from the quantum well layer 24 was obtained.

  In the first embodiment, in particular, by applying a high integration technology in a silicon semiconductor, it is possible to control the size on the order of several μm.

  In addition, if the light emitting element described in Example 1 or Example 2 to Example 4 described later is arranged in a desired arrangement state and the light emitting element emits light by, for example, irradiating the light emitting element with laser light, It can function as a photoluminescence (PL) type display device.

  The second embodiment is a modification of the first embodiment. In Example 2, the same steps as [Step-100] and [Step-120] to [Step-140] were performed. That is, [Step-110] was omitted.

Thus, in Example 2, the first material layer 21 made of SiO ₂ and having a thickness of 200 nm is formed on the substrate 11, and the first material layer 21 is made of silicon (Si) having a thickness of 10 nm. A quantum well layer 24 is formed, a second material layer 22 made of SiO ₂ and having a thickness of 200 nm is formed on the quantum well layer 24, and terbium ions (Tb ³⁺ ) introduced only into the second material layer 22 are formed. A light emitting device in which the concentration peak in the thickness direction was located at a position about 10 nm away from the quantum well layer 24 could be obtained.

The third embodiment is also a modification of the first embodiment. In Example 3, in a layer containing rare earth atoms, the concentration peak of rare earth atoms in the thickness direction is within a range where energy transition occurs by a Dexter mechanism from the interface between this layer and the quantum well layer (quantum well layer). In the range in which the energy of the carriers confined in can be transferred to the rare earth atoms. Specifically, in Example 3, in the layer containing rare earth atoms (in Example 3, both the first material layer 21 and the second material layer 22), The concentration peak of the rare earth atoms is located within the range of 1 × 10 ⁻⁹ m (1 nm) from the interface between the first material layer 21 and the quantum well layer 24, and the interface between the second material layer 22 and the quantum well layer 24 To 1 × 10 ^-9 m (1 nm). In the same step as [Step-110], for example, conditions for ion implantation into the first material layer 21 when the rare earth atom 23 is terbium (Tb) are exemplified in Table 4 below, and [Step- 140], ion implantation conditions for the second material layer 22 are exemplified in Table 5 below.

[Table 4]
Acceleration energy: 0.1 keV to 3 keV
Ion species: Tb ³⁺
Dose amount: 1 × 10 ¹³ atoms / cm ²

[Table 5]
Acceleration energy: 620 keV
Ion species: Tb ³⁺
Dose amount: 1 × 10 ¹³ atoms / cm ²

Thus, in Example 3, the first material layer 21 made of SiO ₂ and having a thickness of 200 nm is formed on the substrate 11, and the first material layer 21 having the thickness of 10 nm made of silicon (Si) is formed. A quantum well layer 24 is formed, a second material layer 22 having a thickness of 200 nm made of SiO ₂ is formed on the quantum well layer 24, and terbium ions (introduced into the first material layer 21 and the second material layer 22 ( It was possible to obtain a light emitting device in which the concentration peak in the thickness direction of (Tb ³⁺ ) was located at a position about 1 nm away from the quantum well layer 24.

  Hereinafter, the introduction position of rare earth atoms (more specifically, ions derived from rare earth atoms in Examples 1 and 3) in the light emitting devices of Examples 1 and 3 will be described. Here, it is assumed that the concentration peak of the rare earth atoms in the thickness direction in the layer including the rare earth atoms 23 is separated from the interface between this layer and the quantum well layer by a distance “d”.

  When the value of d is 100 nm, for example, the quantum well layer 24 and the rare earth atom 23 may be close to each other within 10 nm where energy transition due to the Forster mechanism is expected. It can be expected that the light emission efficiency of the light emitting element is improved as compared with the case where it does not exist.

  On the other hand, when the value of d is 10 nm, for example, it is said that the upper limit of the moving distance based on the Forster mechanism (Foerster mechanism), which is energy transfer by a resonant dipole-dipole interaction, is 10 nm. A significant improvement in energy transition efficiency can be expected.

  Furthermore, when the value of d is 1 nm, for example, the upper limit of the movement distance based on the Dexter mechanism (also called the Dexter mechanism or exchange mechanism), which is energy transfer by the exchange of electrons due to intermolecular contact, is 1 nm. It can be expected that the energy transition efficiency will be further improved.

[Comparative Example 1]
As Comparative Example 1, the same steps as [Step-100] to [Step-140] were performed. However, in a step similar to [Step-110], the rare earth atoms 23 (more specifically, such that the concentration peak of the rare earth atoms 23 in the thickness direction is located at a position of 100 nm from the surface of the first material layer 21. Are ion-implanted (see the ion implantation conditions in Table 6). Further, the concentration peak of the rare earth atoms 23 in the thickness direction is located at the position of 100 nm in the second material layer 22 from the interface between the quantum well layer 24 and the second material layer 22 (in other words, the second material Rare earth atoms 23 (more specifically, ions derived from rare earth atoms) are ion-implanted (see the ion implantation conditions in Table 6) so that the surface of the layer 22 is located at a depth of 100 nm.

[Table 6]
Acceleration energy: 300 keV
Ion species: Tb ³⁺
Dose amount: 1 × 10 ¹³ atoms / cm ²

Thus, in Comparative Example 1, the first material layer 21 made of SiO ₂ and having a thickness of 200 nm is formed on the substrate 11, and the first material layer 21 having a thickness of 10 nm made of silicon (Si) is formed. A quantum well layer 24 is formed, a second material layer 22 having a thickness of 200 nm made of SiO ₂ is formed on the quantum well layer 24, and terbium ions (introduced into the first material layer 21 and the second material layer 22 ( A light emitting element in which the concentration peak in the thickness direction of (Tb ³⁺ ) was located at a position about 100 nm away from the quantum well layer 24 could be obtained.

[Comparative Example 2]
Moreover, the same process as the comparative example 1 was performed as the comparative example 2. However, [Step-110] was omitted.

Thus, in Comparative Example 2, the first material layer 21 made of SiO ₂ and having a thickness of 200 nm is formed on the substrate 11, and the first material layer 21 having a thickness of 10 nm made of silicon (Si) is formed. A quantum well layer 24 is formed, a second material layer 22 made of SiO ₂ and having a thickness of 200 nm is formed on the quantum well layer 24, and terbium ions (Tb ³⁺ ) introduced only into the second material layer 22 are formed. A light emitting device in which the concentration peak in the thickness direction is located about 100 nm away from the quantum well layer 24 was obtained.

[Comparative Example 3]
Furthermore, as Comparative Example 3, the same steps as [Step-100] to [Step-140] were performed. However, in a step similar to [Step-120], without forming a quantum well layer, a SiO ₂ layer having a thickness of 10 nm is formed on the first material layer 21 based on, for example, a PE-CVD method, In the same step as [Step-130], the second material layer 22 was formed on this SiO ₂ layer. This SiO ₂ layer is not a quantum well layer.

Thereby, in the Comparative Example 3, on the substrate 11, the first material layer 21 having a thickness of 200nm composed of SiO ₂ is formed, SiO ₂ layer is formed on the first material layer 21, SiO ₂ layer A second material layer 22 made of SiO ₂ and having a thickness of 200 nm is formed thereon, and a concentration peak in the thickness direction of terbium ions (Tb ³⁺ ) introduced into the first material layer 21 and the second material layer 22 is observed. The light emitting device of Comparative Example 3 located at a position about 10 nm away from the SiO ₂ layer could be obtained.

[Comparative Example 4]
Moreover, the same process as Example 1 was performed as the comparative example 4 for the comparison. However, [Step-110] was omitted, and the thickness of the quantum well layer 24 was set to 100 nm.

Thus, in Comparative Example 4, the first material layer 21 made of SiO ₂ and having a thickness of 200 nm is formed on the substrate 11, and the first material layer 21 having a thickness of 100 nm made of silicon (Si) is formed. A quantum well layer 24 is formed, a second material layer 22 made of SiO ₂ and having a thickness of 200 nm is formed on the quantum well layer 24, and terbium ions (Tb ³⁺ ) introduced only into the second material layer 22 are formed. A light emitting device in which the concentration peak in the thickness direction was located at a position about 10 nm away from the quantum well layer 24 could be obtained.

  The optical characteristics of the light emitting devices of Examples 1 to 3 and Comparative Examples 1 to 4 thus obtained were evaluated using a photoluminescence measuring device (excitation light: He—Cd laser, excitation power: 30 mW, detector: silicon photo). The detector was used in a room temperature environment. Specifically, light emitted from a light emitting element irradiated with a He—Cd laser is received by a silicon photodetector, and photoluminescence emission intensity of light having an emission peak in the vicinity of a wavelength of 545 nm (hereinafter simply referred to as emission intensity). ) Was read. Table 7 shows the results of the optical characteristics. The light emission intensity is expressed as a relative value when the light emission intensity value of Example 1 is “1”. In Table 7, the photoluminescence emission intensity is simply expressed as “emission intensity”.

[Table 7]

  From Table 7, it can be seen that the light emission intensity of the light emitting elements of Example 1 and Example 2 is higher than the light emission intensity of the light emitting element of Comparative Example 3 because the quantum well layer 24 is present. The light emission intensity of the light emitting elements of Comparative Example 1 and Comparative Example 2 is higher than the light emission intensity of the light emitting element of Comparative Example 3 because the quantum well layer 24 is present, but a layer containing rare earth atoms 23. Since the optimization of the position of the concentration peak of the rare earth atom in the thickness direction in FIG. 2 is not achieved, it can be seen that the emission intensity of the light emitting elements of Example 1 and Example 2 is lower. Furthermore, it can be seen that the light emission intensity of the light emitting element of Example 3 (d = 1 nm) is higher than the light emission intensity of the light emitting elements of Example 1 and Example 2 (d = 10 nm). In addition, it can be seen from Comparative Example 4 that the emission intensity decreases when the quantum well layer is thick.

From the above analysis results, according to Examples 1 to 3, the light-emitting layer formed on the substrate is divided into a quantum well layer, a first material layer made of SiO ₂ containing terbium ions as rare earth atoms, and / or Alternatively, by comprising the second material layer, a higher emission intensity can be obtained as compared with the light emitting device (Comparative Example 3) in which terbium ions are simply dispersed in the SiO ₂ layer that is an insulator (that is, Higher emission efficiency), and by optimizing the position of the concentration peak of the rare earth atoms in the thickness direction in the layer containing the rare earth atoms 23, higher emission intensity can be obtained. You can see that

  Example 4 relates to a light-emitting element according to the second aspect of the present invention and a method for manufacturing the light-emitting element according to the second aspect of the present invention.

A schematic partial cross-sectional view of the light-emitting element of Example 4 is shown in FIG. The light-emitting element 30 of Example 4 includes a light-emitting layer 40 formed on a substrate 31 (corresponding to a base) made of a silicon semiconductor substrate. In Example 4, the light emitting layer 40 includes the quantum dots 41 and rare earth atoms 43 attached to the surfaces of the quantum dots 41. In FIG. 2A, the quantum dots 41 are shown to be regularly arranged, but in reality, the quantum dots 41 are randomly arranged. Here, the quantum dots 41 are made of silicon (Si) and exist in a kind of dispersed state in the material layer 42 made of silicon oxide (SiO ₂ ).

The rare earth atom 43 is eurobium (Eu). In this case, the light emitting element containing Eu ³⁺ emits red light (wavelength: 615 nm), or the rare earth atom 43 is praseodymium (Pr). In this case, Pr ^The light emitting element containing ³⁺ emits red light (wavelength: 605 nm), or the rare earth atom 43 is erbium (Er). In this case, the light emitting element containing Er ³⁺ emits orange light (wavelength: 570 nm). Alternatively, the rare earth atom 43 is terbium (Tb). In this case, the light emitting element containing Tb ³⁺ emits green light (wavelength: 545 nm), or the rare earth atom 43 is cerium (Ce). in this case, the light-emitting element including Ce ³⁺ blue (wavelength: 530 nm) to emit Alternatively, the rare earth atom 43 is thulium (Tm), in this case, including the Tm ³⁺ Photoelement blue (wavelength: 450 nm) to emit. The rare earth atom 43 may be composed of a plurality of kinds of rare earth atoms as described above or other than that, and the emission color in this case is a mixture of specific emission colors emitted by the rare earth atoms.

  Hereinafter, the manufacturing method of the light emitting element of Example 4 will be described.

[Step-400]
First, a porous silicon semiconductor substrate is obtained by anodic oxidation (anodization) of a silicon semiconductor substrate, and then the silicon semiconductor substrate is subjected to ultrasonic treatment in a solvent to obtain quantum dots 41 made of silicon. .

Specifically, as shown in a conceptual diagram in FIG. 2B, a silicon semiconductor substrate (for example, a p-type silicon semiconductor substrate: resistivity = 1 Ωcm to 10 Ωcm) 44 is mixed with hydrofluoric acid (50 wt%) and ethanol. In the electrolytic solution 45 mixed with the solution at a volume ratio of 1: 1, the silicon semiconductor substrate 44 is made porous by anodizing (anodizing) at a current density of 100 mA / cm ² . That is, a porous silicon semiconductor substrate is obtained. At this time, the silicon semiconductor substrate 44 is used as an anode, and a platinum electrode 46 is used as a counter electrode.

  Thereafter, the porous silicon semiconductor substrate 44 obtained by anodic oxidation is subjected to ultrasonic treatment in a solvent made of, for example, toluene. As a result, the quantum dots 41 made of silicon are screened off from the porous silicon semiconductor substrate 44 and dispersed in the solvent. Next, the quantum dots 41 dispersed in the solvent are sorted for each size using a centrifuge, and the quantum dots 41 made of silicon having a substantially uniform particle diameter can be obtained. The quantum dots 41 can also be obtained by using a laser ablation method in a rare gas.

[Step-410]
Next, rare earth atoms 43 are attached to the surface of the quantum dots 41 by electroless plating. The plating bath used in the electroless plating method includes, for example, sodium citrate, sodium hypophosphite, and ammonium sulfate. Here, sodium citrate is used as a complexing agent that forms a stable soluble complex with ions forming the plating layer in the plating bath in order to prevent precipitation of hydroxide and adjust the plating rate. In addition, sodium hypophosphite is used as a reducing agent for precipitating the material forming the plating layer. Furthermore, ammonium sulfate is used as a stabilizer that prevents the decomposition of the plating bath. Rare earth element sulfates (e.g., europium (Eu) sulfate, praseodymium (Pr) sulfate, erbium (Er) sulfate, terbium (Tb) sulfate, cerium (Ce) sulfate Sulfate, thulium (Tm) sulfate) is dissolved, and an ammonium hydroxide (NH ₄ OH) solution is added so that the hydrogen ion concentration (pH) is about 8, followed by heating to 90 ° C. Then, the quantum dots 41 made of silicon (Si) obtained in [Step-400] are put into a plating bath and left until a desired amount of rare earth atoms are attached to the surface of the quantum dots 41. Thus, quantum dots 41 containing rare earth atoms can be obtained by electroless plating. After the electroless plating treatment, the quantum dots 41 are washed with ultrapure water, and the plating bath solution is washed away.

  The method of attaching the rare earth atoms 43 to the surface of the quantum dots 41 is not limited to the electroless plating method, and for example, a sputtering method, a CVD method, or an MBE method (molecular beam epitaxial method) can also be employed. An example of a method for causing the rare earth atoms 43 to be included (diffused) in the quantum dots 41 is an ion implantation method.

[Step-420]
Next, the quantum dot 41 obtained in [Step-410] and silicon alkoxide are mixed to obtain a product. Specifically, after mixing the quantum dots 41 and silicon alkoxide, alkali or acid is added as a catalyst to hydrolyze the silicon alkoxide. Thus, a sol or gel product can be obtained.

More specifically, for example, a desired amount of the quantum dots 41 obtained in [Step-410], tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ), and methanol are added to a polypropylene container, and further, Then, water having a molar ratio more than twice that of tetraethoxysilane is added. Further, N, N-dimethylformamide is added to the bottom of the container as a drying control agent and stirred. To this mixed solution is added 0.1N ammonium hydroxide (NH ₄ OH, aqueous ammonia) as a catalyst, and after stirring, the container is covered and left at room temperature for several days. During this time, tetraethoxysilane is hydrolyzed and gelled. Thereafter, the container lid is slightly opened and left at room temperature, the solvent in the container is gradually evaporated, and the contents are gradually dried. Furthermore, it is dried in, for example, a 50 ° C. constant temperature bath to obtain a highly viscous gel product. As the silicon alkoxide, for example, tetramethoxysilane (Si (OCH ₃ ) ₄ ) or the like can be used instead of tetraethoxysilane. Moreover, although 0.1N ammonia aqueous solution was used as a catalyst, it is not limited to this, Hydrochloric acid etc. can also be used.

[Step-430]
Next, after a product obtained by mixing quantum dots 41 and silicon alkoxide is attached to the substrate 31, the product is annealed. Specifically, for example, the gel-like product obtained in [Step-420] is applied to the substrate 31 made of a silicon semiconductor substrate based on a screen printing method.

Next, the gel-like product applied on the substrate 31 made of a silicon semiconductor substrate is annealed. As the conditions for this annealing treatment, for example, a heat treatment at about 400 ° C. to 1000 ° C. in an inert atmosphere such as argon or nitrogen can be exemplified. Thus, it is possible to obtain the quantum dots 41 and the light-emitting layer 40 composed of the rare earth atoms 43 attached to the surface of the quantum dots 41 and / or contained in the quantum dots. In the material layer 42 made of silicon (Si) and silicon oxide (SiO ₂ ), it exists in a kind of dispersed state. The material layer 42 uses tetraethoxysilane as a starting material, and is a result of hydrolysis of tetraethoxysilane.

  In [Step-430], if a gel-like product is applied based on the screen printing method, that is, by coating the light emitting layer of the light emitting element for each light emitting unit (for each pixel), for example, a large screen display device However, the light-emitting layer of the light-emitting element can be formed with high accuracy and with lower energy consumption than the existing gas-phase process. Further, if an electroless plating method is adopted as a method for attaching the rare earth atoms 43 to the surface of the quantum dots 41, it is not necessary to make a high vacuum state, so that it is relatively easy to cope with an increase in the size of the display device. In addition, energy consumption required for the process can be reduced. In addition, when a large-screen display device is produced by a vacuum process, there is a possibility that film formation accuracy may deteriorate. However, if a gel-like product is applied to a substrate based on a screen printing method, a large-screen display device is configured. The light emitting element or the light emitting device to be manufactured can be manufactured with high accuracy.

  Example 5 relates to the light-emitting element and the light-emitting device according to the first aspect or the second aspect of the present invention, specifically, a light-emitting element composed of a current-injection type electroluminescence element, and a plurality of current injections The present invention relates to a light emitting device composed of a type electroluminescent element. As shown in a schematic partial cross-sectional view in FIG. 3A, a light emitting element 60 that is a current injection type electroluminescent element includes a light emitting layer 61 formed on a base (for example, a p-type silicon semiconductor substrate 62). It has. Here, the light emitting layer 61 relates to the structure of the light emitting element according to the first aspect of the present invention described in Examples 1 to 3, or according to the second aspect of the present invention described in Example 4. It has a structure of a light emitting element. The light emitting element 60 in Example 5 is separated from adjacent light emitting elements (not shown) by an insulating layer 65 made of SiN formed on the p-type silicon semiconductor substrate 62. The size and planar shape of the light emitting layer surrounded by the insulating layer 65 may be appropriately selected and determined according to the standard of the display device. For example, a planar shape of 1 mm square can be exemplified.

  The light emitting device 60 of Example 5 can be manufactured by the following manufacturing method. That is, the insulating layer 65 is formed on the surface of the p-type silicon semiconductor substrate 62 corresponding to the base by, for example, the PE-CVD method, the lithography technique, and the etching technique. Next, the method for manufacturing the light-emitting element according to the first aspect of the present invention described in the first to third embodiments or the implementation is performed on the exposed portion of the p-type silicon semiconductor substrate 62 surrounded by the insulating layer 65. The light emitting layer 61 is formed based on the method for manufacturing the light emitting element according to the second aspect of the present invention described in Example 4. Thereafter, the transparent electrode composed of the n-type ITO layer 63 is formed by sputtering, lithography, and etching techniques from the light emitting layer 61 to the insulating layer 65. Further, on the n-type ITO layer 63, sputtering, The metal electrode 64 is formed by a lithography technique and an etching technique.

  Thereafter, one MOS transistor 50 per light emitting element is formed on the p-type silicon semiconductor substrate 62 by a well-known method. The light emitting layer 61 can emit light by causing a current to flow from the power source 51 to the light emitting element 60 by the on / off control of the MOS transistor 50. In some cases, in Example 5 or Example 6 described later, a light reflection layer may be formed below the light emitting layer, whereby the light emitted from the light emitting layer can be efficiently and upwardly emitted from the light emitting element. Can be launched.

  The arrangement of the light-emitting elements constituting the light-emitting device will be described with reference to the schematic diagrams of FIGS. 8 to 17, alphabets “R”, “G”, “B”, and “O” mean light emitting elements that emit red, green, blue, and orange, respectively. A light emitting element that emits red light is called a red light emitting element R, a light emitting element that emits green light is called a green light emitting element G, a light emitting element that emits blue light is called a blue light emitting element B, and a light emitting element that emits orange light. Is called an orange light emitting element O. The arrangement of the light-emitting elements constituting the light-emitting device described with reference to the schematic diagrams of FIGS. 8 to 17 can be applied to the fifth to ninth embodiments.

Further, a first light emitting element (a red light emitting element R including Eu ³⁺ as a rare earth atom) that emits light having a _first wavelength λ ₁ (for example, 615 nm) corresponding to red, corresponds to green. A second light-emitting element that emits light of a _second wavelength λ ₂ (for example, 545 nm) (a green light-emitting element G, including Tb ³⁺ as a rare earth atom), and a third wavelength λ corresponding to blue ₃ One light-emitting element unit (one pixel) is formed by three types of light-emitting elements that emit light of ₃ (for example, 450 nm) (blue light-emitting element B, which includes Tm ³⁺ as a rare earth atom). The light emitting device can be configured to include a plurality of light emitting element units. Alternatively, a first light-emitting element (a red light-emitting element R that includes Eu ³⁺ as a rare earth atom) that emits light having a _first wavelength λ ₁ (for example, 615 nm) corresponding to red, corresponds to green. A second light emitting element that emits light of a _second wavelength λ ₂ (for example, 545 nm) (a green light emitting element G that includes Tb ³⁺ as a rare earth atom), a third wavelength λ ₃ corresponding to blue ( For example, a third light-emitting element that emits light of 450 nm (a blue light-emitting element B, which includes Tm ³⁺ as a rare earth atom), and a fourth wavelength λ ₄ corresponding to an orange color other than that. One light-emitting element unit (corresponding to one pixel) is formed by four types of light-emitting elements (for example, 570 nm) that emits light of 570 nm (an orange light-emitting element O and includes Er ³⁺ as a rare earth atom) The light-emitting device has a plurality of It may be configured to includes an optical element unit.

  In the example shown in FIG. 8, the planar shape of one pixel (one light emitting element unit) indicated by the area surrounded by the dotted line is a rectangle. In the example shown in FIG. 9, the planar shape of one pixel (one light emitting element unit) indicated by a region surrounded by a dotted line is a square. And the planar shape of the light emitting layer which comprises the light emitting elements R, G, B, and O is square, and the light emitting elements R, G, B, and O are arranged in the X direction and the Y direction. In the example shown in FIG. 8, in one pixel (one light emitting element unit), three types of light emitting elements, a red light emitting element R, a green light emitting element G, and a blue light emitting element B, are arranged in order in the Y direction. A plurality of pixels (a plurality of light emitting element units) are arranged in a two-dimensional matrix in the X direction and the Y direction. And in the example shown in FIG. 8, the light emitting element of the same color is arranged in the X direction. On the other hand, in the example shown in FIG. 9, in one pixel (one light emitting element unit) indicated by a region surrounded by a dotted line, a red light emitting element R, a green light emitting element G, a blue light emitting element B, and an orange light emitting element O. The four types of light emitting elements are sequentially arranged in the X direction and the Y direction, and a plurality of pixels (a plurality of light emitting element units) are arranged in a two-dimensional matrix in the X direction and the Y direction. Each of the light emitting elements R, G, B, and O is provided with a transistor (not shown) for on / off control.

  In the example shown in FIGS. 10 and 11, the planar shape of one pixel (one light emitting element unit) indicated by a region surrounded by a dotted line is a rectangle. And the planar shape of the light emitting layer which comprises light emitting element R, G, B, O is a rectangle, and light emitting element R, G, B, O is arranged in the X direction and the Y direction. In the example shown in FIG. 10, in one pixel (one light emitting element unit), the longitudinal direction of the three types of light emitting elements of the red light emitting element R, the green light emitting element G, and the blue light emitting element B extends in the Y direction. These light emitting elements R, G, B are arranged in order in the X direction, and a plurality of pixels (a plurality of light emitting element units) are arranged in a two-dimensional matrix in the X direction and the Y direction. On the other hand, in the example shown in FIG. 11, in one pixel (one light emitting element unit), the lengths of four types of light emitting elements of red light emitting element R, green light emitting element G, blue light emitting element B, and orange light emitting element O are elongated. The direction extends in the Y direction, and the light emitting elements R, G, B, and O are sequentially arranged in the X direction, and a plurality of pixels (a plurality of light emitting element units) are arranged in a two-dimensional matrix in the X direction and the Y direction. Is arranged. Each of the light emitting elements R, G, B, and O is provided with a transistor (not shown) for on / off control.

  In the example shown in FIG. 12, the planar shape of one pixel (one light emitting element unit) indicated by a region surrounded by a dotted line has a shape in which three regular hexagons are combined, and the example shown in FIG. In this case, the planar shape of one pixel (one light emitting element unit) indicated by a region surrounded by a dotted line has a shape in which four regular hexagons are combined. On the other hand, in the example shown in FIG. 14, the planar shape of one pixel (one light emitting element unit) indicated by the area surrounded by the dotted line is an equilateral triangle. In the example shown in FIG. The planar shape of one pixel (one light emitting element unit) indicated by the enclosed region is a rhombus. The planar shape of the light emitting layers constituting the light emitting elements R, G, B, and O is a regular hexagon or a circle, and the light emitting elements R, G, B, and O are in a honeycomb shape, that is, an equilateral triangle. Arranged at the vertices. In the example shown in FIGS. 12 and 14, in one pixel (one light emitting element unit), three types of light emitting elements of the red light emitting element R, the green light emitting element G, and the blue light emitting element B are adjacent to each other. In the example shown in FIG. 12, light emitting elements of the same color are arranged at a predetermined interval in the horizontal direction, and in the example shown in FIG. The light emitting element R, the green light emitting element G, and the blue light emitting element B are arranged in order at predetermined intervals. On the other hand, in the example shown in FIGS. 13 and 15, four types of light emission of red light emitting element R, green light emitting element G, blue light emitting element B, and orange light emitting element O in one pixel (one light emitting element unit). The elements are arranged adjacent to each other. In the example shown in FIG. 13, light emitting elements of the same color are arranged at a predetermined interval in the horizontal direction, and in the example shown in FIG. In the horizontal direction, a red light emitting element R, a green light emitting element G, a blue light emitting element B, and an orange light emitting element O are sequentially arranged at predetermined intervals. Each of the light emitting elements R, G, B, and O is provided with a transistor (not shown) for on / off control.

  In the example shown in FIG. 16, the planar shape of one pixel (one light emitting element unit) indicated by the area surrounded by the dotted line is a regular hexagon. And the planar shape of the light emitting layer which comprises the light emitting elements R, G, and B is a rhombus obtained by dividing a regular hexagon into three equal parts, and the light emitting elements R, G, and B are arranged at the vertices of a regular triangle. Here, in one pixel (one light emitting element unit), three types of light emitting elements of the red light emitting element R, the green light emitting element G, and the blue light emitting element B are arranged adjacent to each other. For example, among the three types of light emitting elements R, G, and B, one type of light emitting element (for example, blue light emitting element B) is arranged in the Y direction. For example, a green light emitting element G is arranged in the direction of 30 degrees diagonally to the left. Each of the light emitting elements R, G, and B is provided with a transistor (not shown) for on / off control.

  In the example shown in FIG. 17, the planar shape of one pixel (one light emitting element unit) indicated by the area surrounded by the dotted line is an equilateral triangle. The planar shape of the light-emitting layers constituting the light-emitting elements R, G, and B is an isosceles triangle obtained by dividing an equilateral triangle into three equal parts, and the three types of light-emitting elements R, G, and B are equilateral triangles. Arranged at the vertices. At that time, the light emitting elements in a certain pixel and the light emitting elements in the pixel adjacent to the light emitting element are arranged so as not to emit light of the same color. Each of the light emitting elements R, G, and B is provided with a transistor (not shown) for on / off control.

  In the display device of Example 5 or Example 6 described later, a self-luminous, lightweight, and thin display device can be realized by using the light emitting element of the present invention. Further, when the rare earth atoms are formed in the light emitting layer based on an ion implantation method, a screen printing method, or the like, in the manufacturing process of the blue light emitting element B, the green light emitting element G, the red light emitting element R, and the orange light emitting element O, Since all processes other than the injection process and screen printing are common to all the light emitting elements, the process can be simplified. Further, when the light emitting layer is formed by a sputtering method or the like, all the processes other than the light emitting layer forming process can be similarly manufactured for all the light emitting elements, so that the process can be simplified. Note that the transistors for controlling on / off of the light emitting elements R, G, B, and O (for example, MOS transistors and thin film transistors) may be formed on the same surface as the base on which the light emitting elements are formed. However, it may be formed on the surface opposite to the surface on which the light emitting element is formed.

  Example 6 also relates to the light-emitting element and the light-emitting device according to the first aspect or the second aspect of the present invention, specifically, a light-emitting element composed of an intrinsic electroluminescence element, and a plurality of intrinsic electroluminescence elements It is related with the light-emitting device comprised from these. As shown in a schematic partial cross-sectional view in FIG. 3B, a light emitting element 70 which is an intrinsic electroluminescence element is a light emitting layer 71 formed on a base (for example, an anode electrode 72 made of a silicon semiconductor substrate). It has. Here, the light emitting layer 71 relates to the structure of the light emitting device according to the first aspect of the present invention described in Examples 1 to 3, or according to the second aspect of the present invention described in Example 4. It has a structure of a light emitting element. The light emitting element 70 in Example 6 is separated from adjacent light emitting elements (not shown) by an insulating layer 75 made of SiN formed on the anode electrode 72. The size and planar shape of the light emitting layer surrounded by the insulating layer 75 may be appropriately selected and determined according to the standard of the display device. For example, a 1 mm square planar shape can be exemplified.

The light emitting device 70 of Example 6 can be manufactured by the following manufacturing method. That is, the insulating layer 75 is formed on the surface of the anode electrode 72 corresponding to the substrate by, for example, PE-CVD, lithography technology, and etching technology. Next, after an insulating film 76 made of SiO ₂ is formed on the exposed anode electrode 72 surrounded by the insulating layer 75, the insulating film 76 of the present invention described in the first to third embodiments is formed on the insulating film 76. The light emitting layer 71 is formed based on the method for manufacturing the light emitting element according to the first aspect or the method for manufacturing the light emitting element according to the second aspect of the present invention described in Example 4. Thereafter, an insulating film 77 made of SiO ₂ is formed on the light emitting layer 71, and then the transparent cathode electrode made of an ITO layer is formed on the insulating film 77 over the insulating layer 75 by a sputtering method, a lithography technique and an etching technique. 73 is further formed, and a metal electrode 74 is formed on the transparent cathode electrode 73 by sputtering, lithography, and etching.

  Thereafter, one MOS transistor 50 per light-emitting element is formed on the anode electrode 72 (silicon semiconductor substrate) by a known method. The light emitting layer 71 of the light emitting element 70 can emit light by forming an electric field based on the voltage applied from the power source 51 by the on / off control of the MOS transistor 50.

  Example 7 also relates to a light-emitting element and a light-emitting device according to the first aspect or the second aspect of the present invention, specifically, a light-emitting element composed of a light-excited light-emitting element and a plurality of light-excited light-emitting elements More specifically, the present invention relates to a light-emitting device that includes a plurality of light-excited light-emitting elements and includes a light-emitting diode. As shown in a schematic partial cross-sectional view in FIG. 4, a light-emitting element 80 that is a light-excited light-emitting element includes a light-emitting layer 81 formed on a base (corresponding to a sealing layer 89). Here, the light emitting layer 81 relates to the structure of the light emitting element according to the first aspect of the present invention described in Examples 1 to 3, or according to the second aspect of the present invention described in Example 4. The method for manufacturing a light emitting device according to the first aspect of the present invention described in Examples 1 to 3 or the method described in Example 4 has the structure of a light emitting device and uses the sealing layer 89 as a base. It can be manufactured by the method for manufacturing a light emitting device according to the second aspect of the present invention.

  In Example 7, a light emitting diode is provided under the sealing layer 89. This light-emitting diode has a P-type electrode 83 formed on a semiconducting, semi-insulating or insulating substrate 82, a P-type cladding layer 84 formed on the P-type electrode 83 in sequence, an active layer 85, N A mold clad layer 86, an N-type electrode 87 formed on the N-type clad layer 86, and a metal electrode 88 formed on the N-type electrode 87. The sealing layer covers the metal electrode 88 and the N-type electrode 87. 89 is formed. The light emitting diode can be manufactured by a known method such as MOCVD. The emission color of the light emitting diode may be appropriately determined according to the standard of the display device. Further, the order of stacking from the P-type electrode 83 to the N-type electrode 87 may be reversed.

  In the light emitting element 80 composed of such a light excitation type light emitting element, the light emitting element 80 can emit light by exciting the light emitting layer 81 in the light emitting element 80 with light emitted from the light emitting diode. In addition, a light reflecting layer may be formed, whereby light emitted from the light emitting layer can be efficiently emitted from the light emitting element.

  Example 8 also relates to the light-emitting element and the light-emitting device according to the first aspect or the second aspect of the present invention, specifically, a light-emitting element including a light-excitation light-emitting element, and a plurality of light-excitation light-emitting elements More specifically, the present invention relates to a plasma display device.

  The plasma display device of Example 8 whose partial exploded perspective view is shown in FIG. 5 is a three-electrode type plasma display device, in which a first panel 90 and a second panel 94 are joined at their outer peripheral portions. Become. Here, the first panel 90 includes a transparent first substrate 91, a plurality of pairs of discharge sustaining electrodes 92A which are provided on the first substrate 91 in a stripe shape and are made of a transparent conductive material such as ITO, for example, and discharge sustaining electrodes. A bus substrate 92B made of a material having a lower electrical resistivity than the discharge sustaining electrode 92A and a first substrate including the bus electrode 92B and the discharge sustaining electrode 92A provided on the discharge sustaining electrode 92A in order to reduce the impedance of the 92A A dielectric layer 93A formed on 91 and a protective film 93B made of MgO formed on the dielectric layer 93A.

  On the other hand, the second panel 94 includes a second substrate 95, a plurality of address electrodes (also referred to as data electrodes) 96 provided in stripes on the second substrate 95, and a second substrate 95 including the address electrodes 96. A dielectric material layer 97 formed on the dielectric material layer 97, an insulating partition 98 extending in parallel with the address electrode 96 in a region between the adjacent address electrodes 96 on the dielectric material layer 97, and the dielectric material layer 97 To a light emitting region 99 provided on the side wall surface of the partition wall 98. When performing color display in the plasma display device, the light emitting region 99 includes a red light emitting region 99R composed of a red light emitting element R, a green light emitting region 99G composed of a green light emitting element G, and a blue light emitting region 99B composed of a blue light emitting element B. The light emitting areas 99R, 99G, and 99B of these colors are provided in a predetermined order. FIG. 5 is a partial exploded perspective view. In actuality, the top of the partition wall 98 on the second panel 94 side is in contact with the protective film 93B on the first panel 90 side. A discharge gas made of a mixed gas of Ne (neon) and Xe (xenon), for example, is sealed in the discharge space surrounded by the adjacent barrier ribs 98, the light emitting region 99, and the protective film 93B.

  The direction in which the projected image of the discharge sustaining electrode 92A extends and the direction in which the projected image of the address electrode 96 extend are orthogonal to each other, and a pair of the sustaining electrode 92A and the light emitting regions 99R, 99G, and 99B that emit three primary colors. A region where and overlap each other corresponds to one pixel (one pixel). This type of plasma display device is referred to as a “surface discharge type” because glow discharge occurs between the pair of discharge sustaining electrodes 92A. A region where the pair of discharge sustaining electrodes 92A and the address electrode 96 positioned between the two barrier ribs 98 overlap corresponds to a discharge cell and to a sub-pixel. That is, one discharge cell (one sub-pixel) includes one light emitting region 99, a pair of discharge sustaining electrodes 92A, and one address electrode 96.

  In driving the plasma display device, immediately before applying a voltage between the pair of discharge sustaining electrodes 92A, for example, by applying a pulse voltage lower than the discharge start voltage of the discharge cell to the address electrode 96, the dielectric layer 93A The charge is accumulated (selection of discharge cell for display), and the apparent discharge start voltage is lowered. The discharge started between the pair of discharge sustaining electrodes 92A can be maintained at a voltage lower than the discharge start voltage. In the discharge cell, the light emitting region 99 excited by the irradiation of vacuum ultraviolet rays generated based on the glow discharge in the discharge gas exhibits a specific emission color corresponding to the type of rare earth atom. A vacuum ultraviolet ray having a wavelength corresponding to the type of the enclosed discharge gas is generated.

  Here, the light emitting region 99 functions as a so-called phosphor layer constituting a conventional plasma display device. The red light emitting element R, the green light emitting element G, and the blue light emitting element B constituting the light emitting region 99 have the structure of the light emitting element according to the second aspect of the present invention described in Example 4, and the second substrate 95 is formed. The substrate can be manufactured by the method for manufacturing a light emitting device according to the second aspect of the present invention described in Example 4.

  Example 9 also relates to a light-emitting element and a light-emitting device according to the first aspect or the second aspect of the present invention, specifically, a light-emitting element composed of an electron beam-excited light-emitting element, and a plurality of electron beams More specifically, the light-emitting device includes a plurality of electron-beam-excited light-emitting elements and includes a plurality of cold cathode field emission devices (more specifically, Cold cathode field emission display).

  As an example, a conceptual partial end view of a cold cathode field emission display device having a Spindt type cold cathode field emission device (hereinafter abbreviated as field emission device) is shown in FIG. FIG. 7 shows a schematic exploded perspective view of a part of the cathode panel CP and the anode panel AP when the panel AP is disassembled.

  A Spindt-type field emission device, which is an electron emission source, includes a cathode electrode 111 formed on a support 110, an insulating layer 112 formed on the support 110 and the cathode electrode 111, and a gate formed on the insulating layer 112. An electrode 113, an opening 114 provided in the gate electrode 113 and the insulating layer 112 (a first opening 114A provided in the gate electrode 113 and a second opening 114B provided in the insulating layer 112), and an opening It is composed of a conical electron emission portion 115 formed on the cathode electrode 111 located at the bottom of 114.

  In the cold cathode field emission display, the cathode electrode 111 has a strip shape extending in the first direction, and the gate electrode 113 has a strip shape extending in a second direction different from the first direction (see FIG. 7). In general, the cathode electrode 111 and the gate electrode 113 are each formed in a strip shape in a direction in which the projected images of both the electrodes 111 and 113 are orthogonal to each other. An overlapping region where the strip-shaped cathode electrode 111 and the strip-shaped gate electrode 113 overlap is an electron emission region EA, which corresponds to one sub-pixel. The electron emission areas EA are normally arranged in a two-dimensional matrix within the effective area of the cathode panel CP (area that functions as an actual display portion).

  On the other hand, the anode panel AP has a light emitting area 122 (specifically, a red light emitting area 122R composed of a red light emitting element R and a green light emitting area 122G composed of a green light emitting element G) on a substrate 120 corresponding to a base. , And a blue light emitting region 122B made of the blue light emitting element B), and the light emitting region 122 made of the light emitting element is covered with the anode electrode 124. These light emitting regions 122 are embedded with a light absorbing layer (black matrix) 123 made of a light absorbing material such as carbon to prevent display image color turbidity and optical crosstalk. Yes. In the figure, reference numeral 121 represents a partition, reference numeral 126 represents a spacer, reference numeral 125 represents a spacer holding portion, reference numeral 127 represents a frame, and reference numeral 116 represents a focusing electrode. In FIG. 7, illustration of the partition walls, the spacers, the spacer holding portion, and the focusing electrode is omitted.

  Here, the light emitting region 122 functions as a so-called phosphor layer in an anode panel constituting a conventional cold cathode field emission display. The red light-emitting element R, green light-emitting element G, and blue light-emitting element B constituting the light-emitting region 122 have the structure of the light-emitting element according to the second aspect of the present invention described in Example 4, and the substrate 120 is used as a base. The light emitting device manufacturing method according to the second aspect of the present invention described in Example 4 can be used.

  One sub-pixel is composed of an electron emission area EA on the cathode panel side and a light emission area 122 on the anode panel side facing a group of these field emission elements. In the effective area, such pixels are arranged on the order of hundreds of thousands to millions, for example.

Then, the anode panel AP and the cathode panel CP are arranged so that the electron emission area EA and the light emitting area 122 face each other, joined at the peripheral edge via the frame body 127, and then exhausted and sealed. A cold cathode field emission display can be produced. A space surrounded by the anode panel AP, the cathode panel CP, and the frame body 127 is in a high vacuum (for example, 1 × 10 ⁻³ Pa or less).

  A relatively negative voltage is applied to the cathode electrode 111 from the cathode electrode control circuit 131, a relatively positive voltage is applied to the gate electrode 113 from the gate electrode control circuit 132, and the anode electrode 124 is applied to the anode electrode 124 more than the gate electrode 113. Further, a higher positive voltage is applied from the anode electrode control circuit 133. In the case of performing display in such a cold cathode field emission display device, for example, a scanning signal is input from the cathode electrode control circuit 131 to the cathode electrode 111, and a video signal is input from the gate electrode control circuit 132 to the gate electrode 113. Alternatively, a video signal is input from the cathode electrode control circuit 131 to the cathode electrode 111, and a scanning signal is input from the gate electrode control circuit 132 to the gate electrode 113. Electrons are emitted from the electron emitter 115 based on the quantum tunnel effect due to an electric field generated when a voltage is applied between the cathode electrode 111 and the gate electrode 113, and the electrons are attracted to the anode electrode 124. It passes through and collides with the red light emitting element R, the green light emitting element G, and the blue light emitting element B constituting the light emitting region 122. As a result, the red light emitting element R, the green light emitting element G, and the blue light emitting element B constituting the light emitting region 122 emit light, and a desired image can be obtained. That is, the operation of this cold cathode field emission display is basically controlled by the voltage applied to the gate electrode 113 and the voltage applied to the cathode electrode 111.

Instead of the cold cathode field emission device, the electron emission source may be composed of an electron emission device commonly called a surface conduction electron emission device. This surface conduction electron-emitting device is made of tin oxide (SnO ₂ ), gold (Au), indium oxide (In ₂ O ₃ ) / tin oxide (SnO ₂ ), carbon, palladium oxide (PdO), etc. A pair of electrodes made of a conductive material, having a very small area and arranged with a predetermined gap (gap) are formed in a matrix. A carbon thin film is formed on each electrode. The row direction wiring is connected to one electrode of the pair of electrodes, and the column direction wiring is connected to the other electrode of the pair of electrodes. By applying a voltage to the pair of electrodes, an electric field is applied to the carbon thin films facing each other across the gap, and electrons are emitted from the carbon thin film. By causing the electrons to collide with the red light emitting element R, the green light emitting element G, and the blue light emitting element B constituting the light emitting area on the anode panel, the light emitting area emits light, and a desired image can be obtained. Alternatively, the electron emission source can be composed of a metal / insulating film / metal element.

  As mentioned above, although this invention was demonstrated based on the preferable Example, this invention is not limited to these Examples.

In the first to third embodiments, the film thickness of the first material layer 21 and the second material layer 22 is 200 nm. However, the thickness is not limited to such a thickness, and the thickness of the quantum well layer 24 is Although it is 10 nm, it is not limited to such a thickness. Moreover, the quantum well layer 24 can be comprised from a semiconductor two-dimensional quantum well, a semiconductor one-dimensional quantum well (for example, quantum wire), and a semiconductor zero-dimensional quantum well (for example, quantum dot, nanocrystal). Further, the position (d) of the concentration peak of the rare earth atoms in the thickness direction in the layer containing the rare earth atoms can be appropriately changed according to the rare earth atoms used, the emission intensity, and the like. In addition, although the case of a silicon layer has been described as a material constituting the quantum well layer 24, a silicon-based oxide (SiO _x (0 <X ≦ 2), a silicon-based compound such as silicon nitride containing silicon as a main component, It is also possible to use a mixture of silicon compounds, a so-called silicon group material such as Ge, a mixture of silicon group materials, other semiconductor materials and mixtures thereof.

1A to 1C are schematic partial cross-sectional views of a substrate and the like for explaining the method for manufacturing the light-emitting element of Example 1. FIG. 2A is a schematic partial cross-sectional view of the light emitting device of Example 4, and FIG. 2B is an anodic oxidation method suitable for performing the method of manufacturing the light emitting device of Example 4. It is a conceptual diagram of the apparatus for performing. 3A and 3B are schematic partial cross-sectional views of a light emitting device including a current injection type electroluminescent element and a light emitting device including a light emitting element composed of an intrinsic electroluminescent element, respectively. is there. FIG. 4 is a schematic partial cross-sectional view of a light-emitting device including a light-emitting element composed of a light-excited light-emitting element. FIG. 5 is a schematic exploded perspective view of a part of the first panel and the second panel when the first panel and the second panel constituting the plasma display device as the light emitting device are disassembled. FIG. 6 is a conceptual partial end view of a cold cathode field emission display device which is a light emitting device including a light emitting element composed of an electron beam excitation type light emitting element. FIG. 7 is a schematic exploded perspective view of a part of the cathode panel and the anode panel when the cathode panel and the anode panel constituting the cold cathode field emission display device are disassembled. FIG. 8 is a diagram schematically showing the arrangement of the light emitting elements constituting the light emitting device. FIG. 9 is a diagram schematically showing the arrangement of the light emitting elements constituting the light emitting device. FIG. 10 is a diagram schematically showing the arrangement of the light emitting elements constituting the light emitting device. FIG. 11 is a diagram schematically showing the arrangement of the light emitting elements constituting the light emitting device. FIG. 12 is a diagram schematically showing the arrangement of the light emitting elements constituting the light emitting device. FIG. 13 is a diagram schematically showing an arrangement of light emitting elements constituting the light emitting device. FIG. 14 is a diagram schematically showing the arrangement of the light emitting elements constituting the light emitting device. FIG. 15 is a diagram schematically showing the arrangement of the light emitting elements constituting the light emitting device. FIG. 16 is a diagram schematically showing the arrangement of the light emitting elements constituting the light emitting device. FIG. 17 is a diagram schematically showing the arrangement of the light emitting elements constituting the light emitting device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,30 ... Light emitting element 11,31 ... Substrate, 20 ... Light emitting layer, 21 ... First material layer, 22 ... Second material layer, 23 ... Rare earth atom, 24・ ・ ・ Quantum well layer, 40 luminescent layer, 41 Quantum dot, 42 Material layer, 43 Rare earth atom, 44 Silicon semiconductor substrate, 45 Electrolytic solution, 46 ... Platinum electrode, 50 ... MOS type transistor, 51 ... Power source, 60,70,80 ... Light emitting element, 61,71,81 ... Light emitting layer, 62 ... P-type silicon Semiconductor substrate 63 ... n-type ITO layer 64, 74 ... metal electrode 72 ... anode electrode 73 ... transparent cathode electrode 82 ... substrate 83 ... P-type electrode 84 ... P-type cladding layer, 85 ... Active layer, 86 ... N-type cladding layer, 87 ... Type electrode, 88 ... Metal electrode, 89 ... Sealing layer, CP ... Cathode panel, AP ... Anode panel, 110 ... Support, 111 ... Cathode electrode, 112 ... Insulating layer, 113... Gate electrode, 114, 114A, 114B... Opening, 115... Electron emission portion, 116... Converging electrode, 120. 122R, 122G, 122B ... light emitting region, 123 ... black matrix, 124 ... anode electrode, 125 ... spacer holding part, 126 ... spacer, 127 ... frame, 131 ... Cathode electrode control circuit, 132 ... Gate electrode control circuit, 133 ... Anode electrode control circuit

Claims (15)

A light emitting device comprising a light emitting layer formed on a substrate,
The light emitting layer is composed of a quantum dot and a rare earth atom attached to the surface of the quantum dot and / or contained in the quantum dot. The light emitting device according to claim 1 , wherein the light emitting device is an electroluminescence device. The light emitting device according to claim 2 , wherein the light emitting device is a current injection type electroluminescence device. The light emitting device according to claim 2 , wherein the light emitting device is an intrinsic electroluminescence device. The light emitting device according to claim 1 , wherein the light emitting device is a photoexcited light emitting device. The light emitting device according to claim 1 , wherein the light emitting device is an electron beam excitation type light emitting device. The light emitting device according to claim 1 , wherein the quantum dots are made of silicon. The rare earth atom is at least one rare earth atom selected from the group consisting of eurobium (Eu), praseodymium (Pr), erbium (Er), terbium (Tb), cerium (Ce), and thulium (Tm). The light-emitting element according to claim 1 . A method for producing a light emitting device comprising a light emitting layer formed on a substrate, and comprising a quantum dot and a rare earth atom attached to the surface of the quantum dot and / or contained in the quantum dot. ,
The light emitting layer,
After forming quantum dots,
Diffusing rare earth atoms in the quantum dots and / or attaching rare earth atoms to the surface of the quantum dots;
After the product obtained by mixing quantum dots and silicon alkoxide is attached to the substrate, the product is annealed.
A method for manufacturing a light-emitting element, characterized by being formed. The step of mixing the quantum dots and the silicon alkoxide to obtain a product comprises the step of mixing the quantum dots and the silicon alkoxide and then adding an alkali or an acid as a catalyst to hydrolyze the silicon alkoxide. The manufacturing method of the light emitting element of Claim 9 . The method for manufacturing a light-emitting element according to claim 10 , wherein ammonium hydroxide (NH ₄ OH) is added as a catalyst. The method for producing a light-emitting element according to claim 9 , wherein the silicon alkoxide is tetramethoxysilane (Si (OCH ₃ ) ₄ ) or tetraethoxysilane (Si (OC ₂ H ₅ ) ₄ ). The method for manufacturing a light-emitting element according to claim 9 , wherein the annealing process is performed at a temperature of 100 ° C or higher and 1500 ° C or lower in an inert gas atmosphere including a rare gas or a nitrogen gas. The method for producing a light-emitting element according to claim 9 , wherein the quantum dots are formed by ultrasonically treating a porous silicon semiconductor substrate obtained by anodizing the silicon semiconductor substrate in a solvent. . A light-emitting device including a plurality of light-emitting elements each having a light-emitting layer formed on a substrate,
The light emitting layer which comprises each light emitting element consists of the rare earth atom which adhered to the surface of the quantum dot and this quantum dot, and / or was contained in this quantum dot, The light emitting device characterized by the above-mentioned.

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