JP2007265974A - Light-emitting element, light-emitting device, and electronic apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light-emitting element which can be driven at low voltage, and to provide a light-emitting device and an electronic apparatus with reduced power consumption. <P>SOLUTION: The light-emitting element incorporates a first electrode 101, a first insulating layer 102, a light-emitting layer 103, a second insulating layer 104 and a second electrode 105 on a substrate 100. The light-emitting layer 103 includes a three-dimensional compound ABC<SB>2</SB>(wherein A=Cu or Ag, B=Al, Ga or In, and C=S, Se or Te) which is called the chalcopyrite. By employing such a structure, the light-emitting element which can be driven at low voltage can be provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a light emitting material. In addition, the present invention relates to a light emitting element utilizing electroluminescence. In addition, the present invention relates to a light-emitting device and an electronic device each having a light-emitting element.

  In recent years, display devices in televisions, mobile phones, digital cameras, and the like have been demanded to be flat and thin display devices, and display devices using self-luminous light-emitting elements as display devices to satisfy these requirements. Is attracting attention. One of self-luminous light-emitting elements is a light-emitting element that uses electroluminescence. This light-emitting element is formed by sandwiching a light-emitting material between a pair of electrodes and applying a voltage to the light-emitting element. Light emission can be obtained.

  Such a self-luminous light emitting element has advantages such as higher pixel visibility than a liquid crystal display and no need for a backlight, and is considered to be suitable as a flat panel display element. In addition, it is a great advantage that such a light-emitting element can be manufactured to be thin and light. Another feature is that the response speed is very fast.

  Further, since such a self-luminous light emitting element can be formed into a film shape, surface emission can be easily obtained by forming a large-area element. This is a feature that is difficult to obtain with a point light source typified by an incandescent bulb or LED, or a line light source typified by a fluorescent lamp, and therefore has a high utility value as a surface light source applicable to illumination or the like.

  A light-emitting element using electroluminescence is distinguished depending on whether the light-emitting material is an organic compound or an inorganic compound. Generally, the former is called an organic EL element and the latter is called an inorganic EL element.

Inorganic EL elements are classified into a dispersion-type inorganic EL element and a thin-film inorganic EL element depending on the element structure. The former has a light-emitting layer in which particles of a light-emitting material are dispersed in a binder, and the latter has a light-emitting layer made of a thin film of the light-emitting material. It is common in the point that requires. Note that the obtained light emission mechanism includes donor-acceptor recombination light emission using a donor level and an acceptor level, and localized light emission using inner-shell electron transition of a metal ion. In general, the dispersion-type inorganic EL element often has donor-acceptor recombination light emission, and the thin-film inorganic EL element often has localized light emission.

Although such an inorganic EL element has an advantage that it has a longer life compared to an organic EL element, the light emitting layer generally requires electrons accelerated by a high electric field. It is necessary to apply a voltage of several hundred volts. For example, in recent years, a high-luminance blue light-emitting inorganic EL element required for a full-color display has been developed, and driving of the blue light-emitting inorganic EL element requires a driving voltage of 100 to 200 V (for example, Non-patent document 1). For this reason, the inorganic EL element consumes a large amount of power, and it has been difficult to adopt it for a small-sized display such as a mobile phone.
Japanese Journal of Applied Physics, 1999, Vol. 38, p. L1291-1292

  In view of the above problems, an object of the present invention is to provide a novel light emitting material. Another object is to provide a light-emitting element that can be driven at a low voltage. It is another object to provide a light-emitting device and an electronic device with reduced power consumption. It is another object to provide a light-emitting device and an electronic device that can be manufactured at low cost.

One embodiment of the present invention includes a light-emitting layer including a ternary compound between a pair of electrodes, and the ternary compound includes any one element of Cu or Ag and any one of Al, Ga, and In. And a light-emitting element comprising any one element of S, Se, and Te.

One embodiment of the present invention includes a light-emitting layer between a pair of electrodes, and the light-emitting layer includes a compound ABC ₂ (provided that A = Cu, or Ag, B = Al, Ga, or In, C = S, Se). , Or Te).

Further, according to one embodiment of the present invention, a light emitting layer is provided between a pair of electrodes, and the compound ABC ₂ (where A = Cu, or Ag, B = Al, Ga, or In, C = S, A light-emitting element including a semiconductor layer containing Se or Te).

In the above structure, the light-emitting layer includes a sulfide, an oxide, or a nitride.

Alternatively, in the above structure, the light-emitting layer includes zinc sulfide.

In the above structure, the light-emitting layer includes manganese (Mn), copper (Cu), samarium (Sm), terbium (Tb), erbium (Er), thulium (Tm), europium (Eu), cerium (Ce), It contains any one or more elements of praseodymium (Pr).

In the above structure, the light-emitting layer includes any one or two elements of fluorine (F) and chlorine (Cl).

Alternatively, in the above structure, the light-emitting layer includes an impurity element which forms an acceptor level.

Alternatively, in the above structure, the light-emitting layer includes a first impurity element that forms a donor level and a second impurity element that forms an acceptor level.

  The present invention also includes a light emitting device having the above-described light emitting element. The light-emitting device in this specification includes an image display device, a light-emitting device, or a light source (including a lighting device). Also, a panel in which a light emitting element is formed and a connector, for example, a FPC (Flexible Printed Circuit) or TAB (Tape Automated Bonding) tape or TCP (Tape Carrier Package) tape, a printed wiring board on the end of a TAB tape or TCP The light emitting device also includes all the modules provided with an IC (integrated circuit) directly mounted on a panel on which a light emitting element is formed or a panel in which a light emitting element is formed by a COG (Chip On Glass) method.

  An electronic device using the light-emitting element of the present invention for the display portion is also included in the category of the present invention. Therefore, an electronic device according to the present invention includes a display portion, and the display portion includes the above-described light emitting element and a control unit that controls light emission of the light emitting element.

  The light-emitting element of the present invention can be driven at a low voltage.

  In addition, since the light-emitting device of the present invention includes a light-emitting element that can be driven at a low voltage, power consumption can be reduced. In addition, since a drive circuit with high withstand voltage is unnecessary, a light-emitting device can be manufactured at low cost.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it is easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below.

(Embodiment 1)
In this embodiment mode, a thin film light-emitting element according to the present invention will be described with reference to FIG.

  In the light-emitting element described in this embodiment, a first electrode 101, a second electrode 105, a first insulating layer 102 in contact with the first electrode 101, and a second electrode 105 are provided over a substrate 100. The element structure includes the second insulating layer 104 in contact with the light-emitting layer and the light-emitting layer 103 formed between the first insulating layer 102 and the second insulating layer 104. Although the light-emitting element described in this embodiment can emit light by applying voltage between the first electrode 101 and the second electrode 105, the light-emitting element can operate in either DC driving or AC driving. it can.

  The substrate 100 is used as a support for the light emitting element. As the substrate 100, for example, glass or plastic can be used. Note that any material other than these can be used as long as it functions as a support in the manufacturing process of the light-emitting element.

The material forming the first insulating film 102 and the second insulating film 104 is an inorganic material such as an oxide. For example, barium titanate (BaTiO ₃ ) or tantalum pentoxide (Ta ₂ O ₅ ) having a high relative dielectric constant can be used.

  As the first electrode 101 and the second electrode 105, a metal, an alloy, a conductive compound, a mixture thereof, or the like can be used. Note that in order to obtain surface light emission, one or both of the first electrode 101 and the second electrode 105 needs to be a light-transmitting electrode. For example, as a material for a light-transmitting electrode, indium tin oxide (ITO), indium tin oxide containing silicon oxide (ITSO), indium zinc oxide (IZO), indium oxide containing tungsten oxide and zinc oxide ( IWZO) and the like. These conductive metal oxide films are usually formed by sputtering. For example, IZO can be formed by sputtering using a target in which 1 to 20 wt% of zinc oxide is added to indium oxide. IWZO can be formed by sputtering using a target containing 0.5 to 5 wt% tungsten oxide and 0.1 to 1 wt% zinc oxide with respect to indium oxide. Further, when a light-transmitting electrode is formed using a metal electrode, even a material having a low visible light transmittance can be formed by forming a film with a thickness of about 1 nm to 50 nm, preferably about 5 nm to 20 nm. It can be used as a light electrode. As metal electrodes, aluminum (Al), silver (Ag), gold (Au), platinum (Pt), nickel (Ni), tungsten (W), chromium (Cr), molybdenum (Mo), iron (Fe), Cobalt (Co), copper (Cu), palladium (Pd), or a nitride of a metal material such as titanium nitride (TiN) can be used. In addition to sputtering, an electrode can also be produced using vacuum deposition, CVD, or a sol-gel method.

The light emitting layer 103 is a layer containing a ternary compound ABC ₂ (A = Cu or Ag, B = Al, Ga or In, C = S, Se or Te) called chalcopyrite. Examples of such chalcopyrite compounds include CuAlS ₂ , CuAlSe ₂ , CuAlTe ₂ , CuGaS ₂ , CuGaSe ₂ , CuGaTe ₂ , CuInS ₂ , CuInSe ₂ , CuInTe ₂ , AgAlS ₂ , AgAlSe ₂ , AgAlTe ₂ , AgAlTe ₂ , AgAlTe ₂ , AgAlTe ₂ , AgAlTe ₂ , AgAlTe ₂ , AgAlTe ₂ . There are AgGaSe ₂ , AgGaTe ₂ , AgInS ₂ , AgInSe ₂ , and AgInTe ₂ .

The light-emitting layer 103, the base material used in inorganic EL, may be used those containing chalcopyrite ABC _2. In this case, sulfide, oxide, or nitride can be used as the base material. Examples of the sulfide include zinc sulfide (ZnS), cadmium sulfide (CdS), calcium sulfide (CaS), yttrium sulfide (Y ₂ S ₃ ), gallium sulfide (Ga ₂ S ₃ ), strontium sulfide (SrS), sulfide. Barium (BaS) or the like can be used. As the oxide, for example, zinc oxide (ZnO), yttrium oxide (Y ₂ O ₃ ), or the like can be used. As the nitride, for example, aluminum nitride (AlN), gallium nitride (GaN), indium nitride (InN), or the like can be used. Furthermore, zinc selenide (ZnSe), zinc telluride (ZnTe), and the like can also be used. Calcium sulfide-gallium sulfide (CaGa ₂ S ₄ ), strontium sulfide-gallium sulfide (SrGa ₂ S ₄ ), barium sulfide-gallium (BaGa). _It may be a ternary mixed crystal such as ₂ S ₄ ).

  Further, the light emitting layer 103 may contain an emission center material. Examples of localized emission center materials include manganese (Mn), copper (Cu), samarium (Sm), terbium (Tb), erbium (Er), thulium (Tm), europium (Eu), and cerium (Ce). ), Praseodymium (Pr), etc., any one element or two or more elements can be used. Note that a halogen element such as fluorine (F) or chlorine (Cl) may be added as charge compensation. On the other hand, a light-emitting material containing a first impurity element that forms a donor level and a second impurity element that forms an acceptor level can also be used as the emission center material for donor-acceptor recombination light emission. For example, fluorine (F), chlorine (Cl), aluminum (Al), or the like can be used as the first impurity element. Examples of the second impurity element include copper (Cu), silver (Ag), and the like. Can be used. Note that since a lattice defect or the like may form a donor level, the first impurity element is not necessarily required.

As a manufacturing method for chalcopyrite compound ABC _2, it is possible to use various methods such as a solid phase method or a liquid phase method (coprecipitation method). Also, spray pyrolysis method, metathesis method, precursor thermal decomposition method, reverse micelle method, method combining these methods with high temperature firing, liquid phase method such as freeze-drying method, etc. can be used.

The solid phase method is a method in which an element constituting a chalcopyrite compound or a compound containing the element is weighed, mixed in a mortar, heated and fired in an electric furnace, and synthesized by a solid phase reaction. The firing temperature is preferably 700 to 1500 ° C. This is because when the temperature is lower than 700 ° C., the solid phase reaction does not proceed, and when the temperature is higher than 1500 ° C., the base material is decomposed. In addition, although baking may be performed in a powder state, it is preferable to perform baking in a pellet state. The synthesis of a light emitting material by a solid phase method requires firing at a relatively high temperature, but is a simple method and thus has high productivity and is suitable for mass production.

The liquid phase method (coprecipitation method) is a synthesis method in which an element constituting a chalcopyrite compound or a compound containing the element is reacted in a solution, dried, and then fired. In the synthesis of the light emitting material by the liquid phase method, the particles of the light emitting material are uniformly distributed and the particle size is small, so that the reaction can proceed even at a low firing temperature.

Here, a method for synthesizing a chalcopyrite compound using a solid phase method will be described. First, compound A ₂ C and compound B ₂ C ₃ are weighed so as to have a molar ratio of 1: 1, and mixed in a mortar. Then, it heats with an electric furnace and performs baking. At the time of firing, firing may be performed after performing a vacuum sealed tube, or firing may be performed while flowing a gas containing a chalcogen element. Examples of the gas containing a chalcogen element include hydrogen sulfide (H ₂ S). The firing temperature is preferably 700 to 1500 ° C., and firing is preferably performed in a pellet state rather than a powder state.

As the compound A ₂ C, copper sulfide (Cu ₂ S), copper selenide (Cu ₂ Se), copper telluride (Cu ₂ Te), silver sulfide (Ag ₂ S), silver selenide (Ag ₂ Se), Alternatively, silver telluride (Ag ₂ Te) can be used. Examples of the compound B ₂ C ₃ include aluminum sulfide (Al ₂ S ₃ ), aluminum selenide (Al ₂ Se ₃ ), aluminum telluride (Al ₂ Te ₃ ), gallium sulfide (Ga ₂ S ₃ ), gallium selenide ( Ga ₂ Se ₃ ), gallium telluride (Ga ₂ Te ₃ ), indium sulfide (In ₂ S ₃ ), indium selenide (In ₂ Se ₃ ), or indium telluride (In ₂ Te ₃ ) can be used. .

As a method for forming the light emitting layer 103, vacuum evaporation such as resistance heating evaporation or electron beam evaporation (EB evaporation), sputtering, organometallic CVD, hydride transport low pressure CVD, atomic layer epitaxy (ALE), or the like is used. be able to. The film thickness is not particularly limited, but is preferably in the range of 10 to 1000 nm.

  A light-emitting element formed in this manner has a chalcopyrite compound with high electrical conductivity in a light-emitting layer and has a low resistance, and thus can be a light-emitting element that can be driven at a low voltage.

(Embodiment 2)
In this embodiment mode, a thin film light-emitting element according to the present invention will be described with reference to FIG.

  The light-emitting element described in this embodiment includes a first electrode 201 and a second electrode 204 over a substrate 200 and includes a chalcopyrite compound between the first electrode 201 and the second electrode 204. The element structure includes a semiconductor layer 202 and a light emitting layer 203. Although the light-emitting element described in this embodiment can emit light by applying voltage between the first electrode 201 and the second electrode 204, the light-emitting element can operate in either DC driving or AC driving. it can.

As the substrate 200, the first electrode 201, and the second electrode 204, the same materials as those described in Embodiment 1 can be used. As the semiconductor layer 202 containing a chalcopyrite compound, a layer containing the ternary compound ABC ₂ called chalcopyrite described in Embodiment 1 can be used.

  The light-emitting layer 203 is a thin film of a light-emitting material, and a light-emitting material in which a light-emitting center material is added to a base material can be used.

As the base material, sulfide, oxide, or nitride can be used. Examples of the sulfide include zinc sulfide (ZnS), cadmium sulfide (CdS), calcium sulfide (CaS), yttrium sulfide (Y ₂ S ₃ ), gallium sulfide (Ga ₂ S ₃ ), strontium sulfide (SrS), sulfide. Barium (BaS) or the like can be used. As the oxide, for example, zinc oxide (ZnO), yttrium oxide (Y ₂ O ₃ ), or the like can be used. As the nitride, for example, aluminum nitride (AlN), gallium nitride (GaN), indium nitride (InN), or the like can be used. Furthermore, zinc selenide (ZnSe), zinc telluride (ZnTe), and the like can also be used. Calcium sulfide-gallium sulfide (CaGa ₂ S ₄ ), strontium sulfide-gallium sulfide (SrGa ₂ S ₄ ), barium sulfide-gallium (BaGa). _It may be a ternary mixed crystal such as ₂ S ₄ ).

  Examples of the luminescent center material included in the luminescent material include manganese (Mn), copper (Cu), samarium (Sm), terbium (Tb), erbium (Er), and thulium (Tm). ), Europium (Eu), cerium (Ce), praseodymium (Pr), or the like can be used. Note that a halogen element such as fluorine (F) or chlorine (Cl) may be added as charge compensation. On the other hand, the donor-acceptor recombination luminescent center material includes a first impurity element that forms a donor level and a second impurity element that forms an acceptor level. For example, fluorine (F), chlorine (Cl), aluminum (Al), or the like can be used as the first impurity element. For example, copper (Cu), silver (Ag), or the like can be used as the second impurity element. Note that since a lattice defect or the like may form a donor level, the first impurity element is not necessarily required.

As a method for manufacturing the light-emitting material, various methods such as a solid phase method or a liquid phase method (coprecipitation method) can be used. Also, spray pyrolysis method, metathesis method, precursor thermal decomposition method, reverse micelle method, a combination of these methods and high-temperature baking, liquid phase method such as freeze-drying method, etc. can be used.

The solid phase method is a method in which a base material and an element to be contained or a compound containing the element are weighed, mixed in a mortar, heated and fired in an electric furnace, and synthesized by a solid phase reaction. The firing temperature is preferably 700 to 1500 ° C. This is because when the temperature is lower than 700 ° C., the solid phase reaction does not proceed, and when the temperature is higher than 1500 ° C., the base material is decomposed. In addition, although baking may be performed in a powder state, it is preferable to perform baking in a pellet state. The synthesis of a light emitting material by a solid phase method requires firing at a relatively high temperature, but is a simple method and thus has high productivity and is suitable for mass production.

The liquid phase method (coprecipitation method) is a synthesis method in which a base material or a compound containing the base material and an element to be contained or a compound containing the element are reacted in a solution, dried, and then fired. In the synthesis of the light emitting material by the liquid phase method, the particles of the light emitting material are uniformly distributed and the particle size is small, so that the reaction can proceed even at a low firing temperature.

A method for synthesizing a luminescent material by a solid phase method will be described. That is, the base material, the element constituting the donor-acceptor recombination type luminescent center material or the compound containing the element are weighed, mixed in a mortar, and then heated in an electric furnace to be fired. As the base material, the above-described base material can be used. As the donor-acceptor recombination luminescent center material, as the first impurity element or the compound containing the first impurity element, for example, fluorine (F), Chlorine (Cl), aluminum sulfide (Al ₂ S ₃ ), or the like can be used. Examples of the second impurity element or the compound containing the second impurity element include copper (Cu), silver (Ag), and sulfide. Copper (Cu ₂ S), silver sulfide (Ag ₂ S), or the like can be used. The firing temperature is preferably 700 to 1500 ° C. In addition, it is preferable to perform baking in a pellet state rather than a powder state.

  In the case of using a solid phase reaction, a compound composed of the first impurity element and the second impurity element may be used in combination. In this case, since the impurity element is easily diffused and the solid-phase reaction easily proceeds, a uniform light emitting material can be obtained. Further, since no extra impurity element is contained, a light-emitting material with high purity can be obtained. As the compound including the first impurity element and the second impurity element, for example, copper chloride (CuCl), silver chloride (AgCl), or the like can be used.

  In addition, the density | concentration of these impurity elements should just be 0.01-10 atomic% with respect to a base material, Preferably it is the range of 0.05-5 atomic%.

The semiconductor layer 202 containing the chalcopyrite compound and the light emitting layer 203 can be formed by vacuum deposition such as resistance heating deposition or electron beam deposition (EB deposition), sputtering, organometallic CVD, hydride transport reduced pressure CVD, Layer epitaxy (ALE) or the like can be used. The film thickness is not particularly limited, but is preferably in the range of 10 to 1000 nm.

Although not illustrated, a buffer layer may be provided between the semiconductor layer 202 containing a chalcopyrite compound and the first electrode 201, and the light-emitting layer 203 and the second electrode 204. This buffer layer has an effect of reducing the barrier at the interface between the electrode and the semiconductor layer and facilitating carrier injection from the electrode to the semiconductor layer. The buffer layer is not particularly limited. For example, ZnS, ZnSe, ZnTe, CdS, SrS, BaS, or the like, or CuS, Cu ₂ S, or an alkali halide such as LiF, CaF ₂ , BaF ₂ , MgF ₂ or the like can be used.

  The light-emitting element of the present invention efficiently transports carriers to the light-emitting layer by providing a semiconductor layer containing a p-type and n-type bipolar chalcopyrite compound between the electrode and the light-emitting layer. Thus, a light-emitting element that can operate at a low driving voltage can be obtained. In addition, since light can be emitted with a low driving voltage, a light-emitting element with reduced power consumption can be obtained.

(Embodiment 3)
In this embodiment mode, a light-emitting device having a light-emitting element manufactured by applying the present invention will be described.

  In this embodiment, a display device as one embodiment of a light-emitting device will be described with reference to FIGS. FIG. 6 is a schematic configuration diagram showing a main part of the display device.

In FIG. 3, the substrate 410 is provided with a first electrode 416 and a second electrode 418 extending in a direction intersecting with the electrode. At least at a crossing portion between the first electrode 416 and the second electrode 418, a light-emitting layer is provided, and a light-emitting element similar to that described in Embodiment Mode 1 or 2 is formed. In the display device in FIG. 3, a plurality of first electrodes 416 and second electrodes 418 are arranged, light emitting elements to be pixels are arranged in a matrix, and a display portion 414 is formed. In the display portion 414, a moving image and a still image can be displayed by controlling the potentials of the first electrode 416 and the second electrode 418 to control light emission and non-light emission of each light emitting element.

The display device illustrated in FIG. 3 applies a signal for displaying an image to each of the first electrode 416 extending in one direction of the substrate 410 and the second electrode 418 intersecting with the first electrode 416 to emit light from the light emitting element. And non-luminous. That is, the pixel is driven by a simple matrix display device which is exclusively driven by a signal supplied from an external circuit. Since such a display device has a simple configuration, it can be easily manufactured even when the area is increased.

Note that the counter substrate 412 may be provided as necessary, and may be used as a protective member by being provided in accordance with the position of the display portion 414. Further, the protective member may be replaced by applying a resin film or a resin material without using a plate-like hard material. The first electrode 416 and the second electrode 418 are drawn out to an end portion of the substrate 410 to form a terminal connected to an external circuit. That is, the first electrode 416 and the second electrode 418 are connected to the flexible wiring substrates 420 and 422 at the end of the substrate 410, and are connected to an external circuit through the flexible wiring substrate. Examples of the external circuit include a power supply circuit, a tuner circuit, and the like in addition to a controller circuit that controls a video signal.

FIG. 4 is a partially enlarged view showing the configuration of the display unit 414 shown in FIG. A partition layer 424 is formed on a side end portion of the first electrode 416 formed over the substrate 410. An EL layer 426 is formed on at least the first electrode 416. Here, the EL layer 426 includes the first insulating layer, the second insulating layer, and the light-emitting layer described in Embodiment 1 formed between the first insulating layer and the second insulating layer. . Alternatively, the EL layer 426 may have a structure in which a light-emitting layer is provided over the semiconductor layer described in Embodiment 2. The second electrode 418 is provided over the EL layer 426. The second electrode 418 is formed on the partition layer 424 so as to intersect with the first electrode 416. The partition layer 424 is formed using an insulating material so that a short circuit does not occur between the first electrode 416 and the second electrode 418. In a portion where the partition layer 424 covers the end portion of the first electrode 416, a side end portion of the partition layer 424 is given a gradient so that a step is not steep so as to have a so-called tapered shape. When the partition layer 424 has such a shape, coverage with the EL layer 426 and the second electrode 418 is improved, and defects such as cracks and tears can be eliminated.

FIG. 5 is a plan view of the display portion 414 shown in FIG. 3 and shows the arrangement of the first electrode 416, the second electrode 418, the partition wall layer 424, and the EL layer 426. The auxiliary electrode 428 is preferably provided in order to reduce resistance loss in the case where the second electrode 418 is formed using a light-transmitting oxide conductive film such as indium tin oxide or zinc oxide. In this case, the auxiliary electrode 428 is preferably formed using a high melting point metal such as titanium, tungsten, chromium, or tantalum, or a combination of a high melting point metal and a low resistance metal such as aluminum or silver.

5A and 5B, cross-sectional views taken along lines AB and CD are shown in FIGS. A light-emitting element in which an EL layer 426 is formed at the intersection of the first electrode 416 and the second electrode 418 is formed. The auxiliary electrode 428 illustrated in FIG. 6B is provided over the partition layer 424 so as to be in contact with the second electrode 418. By providing the auxiliary electrode 428 over the partition layer 424, a light-emitting element formed at the intersection of the first electrode 416 and the second electrode 418 is not shielded, so that the emitted light can be used effectively. Can do. Further, the auxiliary electrode 428 can be prevented from being short-circuited with the first electrode 416.

FIG. 6 shows an example in which the color conversion layer 430 is provided on the counter substrate 412. The color conversion layer 430 is for changing the wavelength of light emitted from the EL layer 426 to change the emission color. In this case, light emitted from the EL layer 426 is preferably high-energy blue light or ultraviolet light. If the color conversion layers 430 are arranged to convert red, green, and blue, respectively, a display device that performs RGB color display can be obtained. Further, the color conversion layer 430 can be replaced with a colored layer (color filter). In that case, the EL layer 426 may be configured to emit white light. The filler 432 fixes the substrate 410 and the counter substrate 412, and may be provided as appropriate.

In the above, aluminum, titanium, tantalum, or the like is used as the first electrode 416, and indium tin oxide, indium tin oxide (ITO), indium tin oxide containing silicon oxide, indium zinc oxide, oxidation is used as the second electrode 418. When a light-transmitting material such as zinc, indium oxide containing tungsten oxide and zinc oxide (IWZO) or the like is used, a display device in which the display portion 414 is formed on the counter substrate 412 side can be obtained. In this case, if a thin oxide film is formed on the surface of the first electrode 416, a barrier layer is formed, and light emission efficiency can be increased by a carrier blocking effect. Light transmission of indium oxide, indium tin oxide (ITO), indium tin oxide containing silicon oxide, indium zinc oxide, zinc oxide, indium oxide containing tungsten oxide and zinc oxide (IWZO), or the like as the first electrode 416 When a conductive material is used and aluminum, titanium, tantalum, or the like is used for the second electrode 418, a display device in which the display portion 414 is formed on the substrate 410 side can be obtained. In addition, when both the first electrode 416 and the second electrode 418 are formed using a light-transmitting electrode, a double-sided display device can be obtained.

Another structure of the display portion 414 is shown in FIG. In the structure of FIG. 7, the side end portion of the first electrode 952 is covered with an insulating layer 953. A partition layer 954 is provided over the insulating layer 953. The side wall of the partition wall layer 954 has an inclination such that the distance between one side wall and the other side wall facing the side wall becomes narrower as it approaches the surface of the substrate 951. That is, the cross section in the short side direction of the partition wall layer 954 has a trapezoidal shape, and the bottom side (side facing the surface direction of the insulating layer 953 and in contact with the insulating layer 953) is the top side (surface of the insulating layer 953). The direction is the same as the direction and is shorter than the side not in contact with the insulating layer 953. In this manner, by providing the partition layer 954, the EL layer 955 and the second electrode 956 can be formed in a self-aligned manner using the partition layer 954.

  In the display device of this embodiment, since the light emitting element emits light at a low voltage, a booster circuit or the like is unnecessary, and the configuration of the device can be simplified.

  Note that this embodiment can be combined with any of the other embodiments as appropriate.

(Embodiment 4)
In this embodiment mode, a light-emitting device having a light-emitting element manufactured by applying the present invention will be described.

  In this embodiment, an active light-emitting device in which driving of a light-emitting element is controlled by a transistor will be described. In this embodiment mode, a light-emitting device including a light-emitting element manufactured by applying the present invention to a pixel portion will be described with reference to FIGS. 8A is a top view illustrating the light-emitting device, and FIG. 8B is a cross-sectional view taken along lines A-A ′ and B-B ′ in FIG. 8A. In FIG. 8, 601 indicated by a dotted line is a source side driver circuit, 602 is a pixel portion, and 603 is a gate side driver circuit. Reference numeral 604 denotes a sealing substrate, reference numeral 605 denotes a sealing material, and the inside surrounded by the sealing material 605 is a space 607.

  Note that a lead wiring 608 in FIG. 8B is a wiring for transmitting signals input to the source side driver circuit 601 and the gate side driver circuit 603, and is from an FPC (flexible printed circuit) 609 serving as an external input terminal. Receives a video signal, a clock signal, a start signal, a reset signal, and the like. Although only the FPC is shown here, a printed wiring board (PWB) may be attached to the FPC. The light-emitting device in this specification includes not only a light-emitting device body but also a state in which an FPC or a PWB is attached thereto.

  Next, a cross-sectional structure is described with reference to FIG. A driver circuit portion and a pixel portion are formed over the element substrate 610. Here, a source-side driver circuit 601 that is a driver circuit portion and one pixel in the pixel portion 602 are illustrated.

  Note that the source side driver circuit 601 is a CMOS circuit in which an n-channel TFT 623 and a p-channel TFT 624 are combined. The driving circuit may be formed of a known CMOS circuit, PMOS circuit, or NMOS circuit. In this embodiment, a driver integrated type in which a drive circuit is formed on a substrate is shown. However, this is not always necessary, and the drive circuit can be formed outside the substrate. Note that the structure of the TFT is not particularly limited. A staggered TFT or an inverted staggered TFT may be used. Further, the crystallinity of a semiconductor film used for the TFT is not particularly limited. An amorphous semiconductor film or a crystalline semiconductor film may be used. Further, the semiconductor material is not particularly limited, and an inorganic compound or an organic compound may be used.

  The pixel portion 602 is formed by a plurality of pixels including a switching TFT 611, a current control TFT 612, and a first electrode 613 electrically connected to the drain thereof. Note that an insulating film 614 is formed to cover an end portion of the first electrode 613. Here, the insulating film 614 is formed by using a positive photosensitive acrylic resin film.

  In order to improve the coverage, a curved surface having a curvature is formed on the upper end portion or the lower end portion of the insulating film 614. For example, in the case where positive photosensitive acrylic is used as the material of the insulating film 614, it is preferable that only the upper end portion of the insulating film 614 has a curved surface having a curvature radius (0.2 μm to 3 μm). As the insulating film 614, either a negative type that becomes insoluble in an etchant by light irradiation or a positive type that becomes soluble in an etchant by light irradiation can be used.

  An EL layer 616 and a second electrode 617 are formed over the first electrode 613. Here, the EL layer 616 includes the first insulating layer, the second insulating layer, and the light-emitting layer described in Embodiment 1 formed between the first insulating layer and the second insulating layer. . Alternatively, the EL layer 616 may have a structure in which a light-emitting layer is provided over the semiconductor layer described in Embodiment 2. At least one of the first electrode 613 and the second electrode 617 has a light-transmitting property, and light emitted from the EL layer 616 can be extracted to the outside.

  Note that various methods can be used for forming the first electrode 613, the EL layer 616, and the second electrode 617. Specifically, chemicals such as resistance heating vapor deposition, vacuum deposition such as electron beam vapor deposition (EB vapor deposition), physical vapor deposition (PVD) such as sputtering, metal organic CVD, hydride transport low pressure CVD, etc. Vapor phase epitaxy (CVD), atomic layer epitaxy (ALE), or the like can be used. In addition, an inkjet method, a spin coating method, or the like can be used. Moreover, you may form using the different film-forming method for each electrode or each layer.

  Further, the sealing substrate 604 is bonded to the element substrate 610 with the sealant 605, whereby the light-emitting element 618 is provided in the space 607 surrounded by the element substrate 610, the sealing substrate 604, and the sealant 605. Yes. Note that the space 607 is filled with a filler, and may be filled with a sealant 605 in addition to an inert gas (such as nitrogen or argon).

  Note that an epoxy-based resin is preferably used for the sealant 605. Further, it is desirable that the sealing material and the filler are materials that do not transmit moisture and oxygen as much as possible. In addition to a glass substrate and a quartz substrate, a plastic substrate made of FRP (Fiberglass-Reinforced Plastics), PVF (polyvinyl fluoride), polyester film, polyester, acrylic, or the like can be used as a material for the sealing substrate 604.

  As described above, a light-emitting device having a light-emitting element manufactured by applying the present invention can be obtained.

  The light-emitting device described in this embodiment includes the light-emitting element described in any of Embodiments 1 and 2, and can operate with a low driving voltage. Therefore, a light-emitting device with reduced power consumption can be obtained.

  In addition, since the light-emitting device described in this embodiment does not require a high withstand voltage driver circuit, the manufacturing cost of the light-emitting device can be reduced. In addition, the light emitting device can be reduced in weight and the drive circuit portion can be reduced in size.

(Embodiment 5)
In this embodiment, electronic devices each including the light-emitting device described in any of Embodiments 3 to 4 will be described. An electronic device described in this embodiment includes the light-emitting element described in any of Embodiments 1 and 2. Therefore, since the light-emitting element with reduced driving voltage is included, an electronic device with reduced consumption electrodes can be provided.

  As an electronic device manufactured by applying the present invention, a video camera, a digital camera, a goggle type display, a navigation system, a sound reproduction device (car audio, audio component, etc.), a computer, a game device, a portable information terminal (mobile computer, A mobile phone, a portable game machine, an electronic book, or the like), and an image playback device (specifically, a digital versatile disc (DVD) or the like) provided with a recording medium, and a display device that can display the image. Device). Specific examples of these electronic devices are shown in FIGS.

  FIG. 9A illustrates a television set according to this embodiment, which includes a housing 9101, a supporting base 9102, a display portion 9103, speaker portions 9104, a video input terminal 9105, and the like. In this television device, the display portion 9103 is formed by arranging light-emitting elements similar to those described in Embodiment Modes 1 and 2 in a matrix. The light-emitting element has a feature of high luminous efficiency and low driving voltage. It is also possible to prevent a short circuit due to an external impact or the like. Since the display portion 9103 which includes the light-emitting elements of the present invention has similar features, the television device has little deterioration in image quality and low power consumption. With such a feature, in the television device using the light-emitting element of the present invention, the deterioration compensation function and the power supply circuit can be significantly reduced or reduced, so that the housing 9101 and the support base 9102 can be reduced in size and weight. It is possible. In the television device according to this embodiment, low power consumption, high image quality, and reduction in size and weight are achieved; therefore, a product suitable for a living environment can be provided.

  FIG. 9B illustrates a computer according to this embodiment, which includes a main body 9201, a housing 9202, a display portion 9203, a keyboard 9204, an external connection port 9205, a pointing mouse 9206, and the like. In this computer, the display portion 9203 includes light-emitting elements similar to those described in Embodiments 1 and 2, arranged in a matrix. The light-emitting element has a feature of high luminous efficiency and low driving voltage. It is also possible to prevent a short circuit due to an external impact or the like. Since the display portion 9203 which includes the light-emitting elements of the present invention has similar features, this computer has little deterioration in image quality and low power consumption. With such a feature, a deterioration compensation function and a power supply circuit can be significantly reduced or reduced in a computer using the light-emitting element of the present invention, so that the main body 9201 and the housing 9202 can be reduced in size and weight. Is possible. Since the computer according to this embodiment has low power consumption, high image quality, and reduced size and weight, a product suitable for the environment can be provided. In addition, the computer according to this embodiment can be carried and has a display portion that is resistant to an external shock when being carried.

  FIG. 9C illustrates a mobile phone according to this embodiment, which includes a main body 9401, a housing 9402, a display portion 9403, an audio input portion 9404, an audio output portion 9405, operation keys 9406, an external connection port 9407, an antenna 9408, and the like. including. In this cellular phone, the display portion 9403 is formed by arranging light-emitting elements similar to those described in Embodiment Modes 1 and 2 in a matrix. The light-emitting element has a feature of high luminous efficiency and low driving voltage. It is also possible to prevent a short circuit due to an external impact or the like. Since the display portion 9403 including the light-emitting element of the present invention has similar features, the cellular phone has little deterioration in image quality and low power consumption. With such a feature, in the mobile phone using the light-emitting element of the present invention, the deterioration compensation function and the power supply circuit can be significantly reduced or reduced, so that the main body 9401 and the housing 9402 can be reduced in size and weight. Is possible. Since the cellular phone according to this embodiment has low power consumption, high image quality, and reduced size and weight, a product suitable for carrying can be provided. In addition, a product having a display portion that is resistant to external impact when being carried can be provided.

  FIG. 9D shows a camera, which includes a main body 9501, a display portion 9502, a housing 9503, an external connection port 9504, a remote control receiving portion 9505, an image receiving portion 9506, a battery 9507, an audio input portion 9508, operation keys 9509, an eyepiece portion. 9510 etc. are included. In this camera, the display portion 9502 is formed by arranging light-emitting elements similar to those described in Embodiment Modes 1 and 2 in a matrix. The light-emitting element has characteristics that light emission efficiency is high, a driving voltage is low, and a short circuit due to an external impact or the like can be prevented. Since the display portion 9502 including the light-emitting element of the present invention has similar features, the camera has little deterioration in image quality and low power consumption. With such a feature, in the camera using the light-emitting element of the present invention, the deterioration compensation function and the power supply circuit can be significantly reduced or reduced, so that the main body 9501 can be reduced in size and weight. Since the camera according to this embodiment has low power consumption, high image quality, and reduced size and weight, a product suitable for carrying can be provided. In addition, a product having a display portion that is resistant to external impact when being carried can be provided.

FIG. 14 shows a sound reproduction device, which is a car audio as a specific example, and includes a main body 701, a display unit 702, and operation switches 703 and 704. The display portion 702 can be realized by the light-emitting device of Embodiment 3 (passive type) or the light-emitting device of Embodiment 4 (active type). The display portion 702 may be formed using a segment type light emitting device. In any case, by using the light-emitting element of the present invention, a bright display portion having a long lifetime can be configured using a vehicle power source (12 to 42 V) while reducing power consumption. In this embodiment, in-vehicle audio is shown, but the present invention may be used for a portable or home audio device.

FIG. 15 shows a portable digital player as an example in which the light-emitting element of the present invention is used for audio other than in-vehicle audio. A digital player shown in FIG. 15 includes a main body 710, a display unit 711, a memory unit 712, an operation unit 713, an earphone 714, and the like. Note that headphones or wireless earphones can be used instead of the earphones 714. The display portion 711 can be realized by the light-emitting device of Embodiment 3 (passive type) or the light-emitting device of Embodiment 4 (active type). The display portion 711 may be formed using a segment type light emitting device. In any case, by using the light-emitting element according to the present invention, display is possible even when a secondary battery (such as a nickel-hydrogen battery) is used. Can be configured. The memory unit 712 uses a hard disk or a nonvolatile memory. For example, by using a NAND nonvolatile memory having a recording capacity of 20 to 200 gigabytes (GB) and operating the operation unit 713, video and audio (music) can be recorded and reproduced. Note that the display unit 702 in FIG. 14 and the display unit 711 in FIG. 15 can reduce power consumption by displaying white characters on a black background. This is particularly effective in a portable audio device.

  As described above, the applicable range of the light-emitting device manufactured by applying the present invention is so wide that the light-emitting device can be applied to electronic devices in various fields. By applying the present invention, an electronic device having a display portion with low power consumption and high reliability can be manufactured.

  In addition, a light-emitting device to which the present invention is applied has a light-emitting element with high emission efficiency, and can also be used as a lighting device. One mode in which the light-emitting element to which the present invention is applied is used as a lighting apparatus is described with reference to FIGS.

  FIG. 10 illustrates an example of a liquid crystal display device using the light-emitting device to which the present invention is applied as a backlight. The liquid crystal display device illustrated in FIG. 10 includes a housing 501, a liquid crystal layer 502, a backlight 503, and a housing 504, and the liquid crystal layer 502 is connected to a driver IC 505. The backlight 503 uses the light-emitting device of the present invention, and a voltage is applied to the terminal 506.

  By using the light-emitting device of the present invention as a backlight of a liquid crystal display device, a backlight with high luminance and long life can be obtained, so that the quality as a display device is improved. The light-emitting device of the present invention is a surface-emitting light-emitting device and can have a large area. Therefore, the backlight can have a large area, and a liquid crystal display device can have a large area. Further, since the light emitting element is thin and has low power consumption, the display device can be thinned and the power consumption can be reduced.

  In addition, since the light-emitting device to which the present invention is applied can emit light with high luminance, the light-emitting device can be used as a headlight for automobiles, bicycles, ships, and the like. FIG. 11 shows an example in which the light emitting device to which the present invention is applied is used as a headlight of an automobile. FIG. 11B is an enlarged cross-sectional view of a portion of the headlight 1000 in FIG. In FIG. 11B, the light-emitting device of the present invention is used as the light source 1011. Light emitted from the light source 1011 is reflected by the reflecting plate 1012 and extracted to the outside. As shown in FIG. 11B, light with higher luminance can be obtained by using a plurality of light sources. FIG. 11C illustrates an example in which the light-emitting device of the present invention manufactured in a cylindrical shape is used as a light source. Light emitted from the light source 1021 is reflected by the reflecting plate 1022 and extracted outside.

  FIG. 12 illustrates an example in which the light-emitting device to which the present invention is applied is used as a table lamp which is a lighting device. A table lamp illustrated in FIG. 12 includes a housing 2001 and a light source 2002, and the light-emitting device of the present invention is used as the light source 2002. Since the light-emitting device of the present invention can emit light with high luminance, the hand can be brightly illuminated when performing fine work.

  FIG. 13 illustrates an example in which the light-emitting device to which the present invention is applied is used as an indoor lighting device 3001. Since the light-emitting device of the present invention can have a large area, it can be used as a large-area lighting device. In addition, since the light-emitting device of the present invention is thin and has low power consumption, it can be used as a lighting device with low thickness and low power consumption. In this manner, in the room where the light-emitting device to which the present invention is applied is used as an indoor lighting device 3001, the television set 3002 according to the present invention as described with reference to FIG. Can be appreciated.

  The lighting device is not limited to those illustrated in FIGS. 11, 12, and 13, and can be applied as various types of lighting devices including lighting of houses and public facilities. In such a case, since the illuminating device according to the present invention has a thin light-emitting medium and thus has a high degree of design freedom, it is possible to provide products with various designs on the market.

  In this example, a light-emitting material used for the light-emitting element of the present invention will be described.

Cu ₂ S and Ga ₂ S ₃ were weighed so as to have a molar ratio of 1: 1, and stirred and mixed using a menor mortar. Next, the mixture was put in an alumina crucible and fired at 1000 ° C. for 4 hours using an electric furnace in an N ₂ atmosphere to synthesize CuGaS ₂ . The obtained luminescent material was dark brown. When excited at a wavelength of 254 nm, blue light emission could be confirmed.

  In this example, a light-emitting material used for the light-emitting element of the present invention will be described.

ZnS as a base material and CuGaS ₂ obtained in Example 1 were weighed so as to have a molar ratio of 1: 1, and stirred and mixed using a menor mortar. The mixture was then placed in an alumina crucible and fired at 1000 ° C. for 4 hours using an electric furnace under N ₂ atmosphere. The obtained luminescent material was dark brown. When excited at a wavelength of 254 nm, blue light emission could be confirmed.

4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a light-emitting element of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 4A and 4B illustrate a light-emitting device of the present invention. 8A and 8B each illustrate an electronic device of the invention. The figure explaining the illuminating device of this invention. The figure explaining the illuminating device of this invention. The figure explaining the illuminating device of this invention. The figure explaining the illuminating device of this invention. 8A and 8B each illustrate an electronic device of the invention. 8A and 8B each illustrate an electronic device of the invention.

Explanation of symbols

100 Substrate 101 First electrode 102 First insulating layer 103 Light emitting layer 104 Second insulating layer 105 Second electrode

Claims (11)

Having a light emitting layer between a pair of electrodes,
The light emitting layer includes a ternary compound,
The ternary compound is
Any one element of Cu or Ag;
Any one element of Al, Ga, or In;
A light-emitting element comprising any one element of S, Se, and Te. Having a light emitting layer between a pair of electrodes,
The light-emitting layer includes a compound ABC ₂ (where A = Cu, or Ag, B = Al, Ga, or In, C = S, Se, or Te). Having a light emitting layer between a pair of electrodes,
A semiconductor layer containing a compound ABC ₂ (A = Cu, or Ag, B = Al, Ga, or In, C = S, Se, or Te) is provided in contact with the light-emitting layer. Light emitting element. In any one of Claims 1 thru | or 3,
The light-emitting element, wherein the light-emitting layer contains sulfide, oxide, or nitride. In any one of Claims 1 thru | or 3,
The light emitting device, wherein the light emitting layer contains zinc sulfide. In claim 4 or claim 5,
The light emitting layer includes manganese (Mn), copper (Cu), samarium (Sm), terbium (Tb), erbium (Er), thulium (Tm), europium (Eu), cerium (Ce), praseodymium (Pr), A light-emitting element comprising any one or more elements. In claim 6,
The light-emitting layer includes one or two elements of fluorine (F) and chlorine (Cl). In claim 4 or claim 5,
The light-emitting element, wherein the light-emitting layer includes an impurity element that forms an acceptor level. In claim 4 or claim 5,
The light-emitting layer includes a first impurity element that forms a donor level and a second impurity element that forms an acceptor level. A light emitting device comprising: the light emitting element according to claim 1; and a control unit that controls light emission of the light emitting element. Having a display,
An electronic apparatus comprising: the light emitting element according to claim 1; and a control unit that controls light emission of the light emitting element.

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