KR102237119B1 - Light emitting device and lighting system - Google Patents

Abstract

The embodiment relates to a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system.
The light emitting device according to the embodiment includes a first conductivity type semiconductor layer; An active layer on the first conductivity type semiconductor layer; _{An Al p} Ga _q In _{1 -p- q} N layer (where 0< _p ≦1, 0≦q≦1) 122 on the active layer; An AlGaN-based superlattice layer on the Al _p Ga _q In _{1 -p- q N layer 122;} And a second conductivity type semiconductor layer on the AlGaN-based superlattice layer.

Description

Light emitting device and lighting system {LIGHT EMITTING DEVICE AND LIGHTING SYSTEM}

The embodiment relates to a light emitting device, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system.

A light emitting device may be generated by combining a group III and a group V element on the periodic table with a p-n junction diode that converts electric energy into light energy. LED can realize various colors by controlling the composition ratio of compound semiconductor.

When the forward voltage is applied, the electrons in the n-layer and the holes in the p-layer are combined to emit energy equivalent to the energy gap between the conduction band and the valence band. This energy is mainly emitted in the form of heat or light, and when it is radiated in the form of light, it becomes a light-emitting device.

For example, nitride semiconductors are attracting great interest in the development of optical devices and high-power electronic devices due to their high thermal stability and wide bandgap energy. In particular, a blue light emitting device, a green light emitting device, and an ultraviolet (UV) light emitting device using a nitride semiconductor have been commercialized and widely used.

In the conventional light emitting device, the active layer, which is a light emitting layer, is formed by repeatedly stacking a quantum well with a small energy band gap and a quantum wall with a large energy band gap, and the electrons injected from the n-layer and the holes injected from the p-layer are quantum wells. They meet each other and emit light by luminescent bonding.

On the other hand, the light emitting device of the conventional structure has the main problem that the luminous efficiency decreases when the amount of injection current increases. This is due to the low hole injection efficiency compared to the electron injection efficiency in the emission layer. It is required to develop a technology that enables holes to be effectively moved from the p-layer toward the n-layer so that the holes are uniformly distributed in the emission layer, and through this, all quantum wells in the emission layer substantially participate in light emission.

1 is a partial photograph of a light emitting device according to the prior art.

According to the prior art, an AlGaN-based electron blocking layer is disposed between the active layer and the p-type semiconductor layer. At the interface between the p-type semiconductor layer and the AlGaN-based electron blocking layer, Mg, a p-type doping element, is diffused or Mg There is a problem in that a diffusion region D is generated as shown in FIG. 1 due to diffusion of a stacking defect generated by doping, thereby deteriorating the quality of a light emitting device. Stacking defects generated by Mg doping include Pyramidal Inversion Domain (PID) diffusion.

On the other hand, if the interface quality is not good, the hole injection is adversely affected, resulting in a problem that the light intensity (Po) decreases or the operating voltage (VF3) increases.

The embodiment is to provide a light emitting device capable of improving luminous intensity or electrical characteristics, a manufacturing method thereof, a light emitting device package, and a lighting system.

The light emitting device according to the embodiment includes a first conductivity type semiconductor layer 112; An active layer 114 on the first conductivity type semiconductor layer 112; _{An Al p} Ga _q In _{1 -p- q} N layer (0< _p ≦1, 0≦q≦1) 122 on the active layer 114; An AlGaN-based superlattice layer 124 on the Al _p Ga _q In _{1 -p- q N layer 122;} And a second conductivity type semiconductor layer 116 on the AlGaN-based superlattice layer 124.

The lighting system according to the embodiment may include a light emitting unit including the light emitting device.

The embodiment is a light emitting device capable of improving the electrical characteristics according to the improvement of the luminous intensity and the operating voltage (VF3) according to the improvement of the hole injection efficiency by improving the interface quality of the light emitting device, the manufacturing method thereof, the light emitting device package And a lighting system.

In addition, according to the embodiment, the internal luminous efficiency may be increased by improving the interface quality and increasing the carrier diffusion function.

1 is a partial photograph of a light emitting device according to the prior art.
2 is a cross-sectional view of a light emitting device according to an embodiment.
3 is an energy bandgap diagram of a light emitting device according to an embodiment.
4 to 6 are manufacturing process diagrams of a light emitting device according to an embodiment.
7 is a cross-sectional view of a light emitting device package according to an embodiment.
8 is an exploded perspective view of a lighting device according to the embodiment.

In the description of the embodiment, each layer (film), region, pattern or structure is "on/over" or "under" of the substrate, each layer (film), region, pad, or patterns. In the case of being described as being formed in, "on/over" and "under" include both "directly" or "indirectly" formed do. In addition, the criteria for the top/top or bottom of each layer will be described based on the drawings.

(Example)

2 is a cross-sectional view of a light emitting device 100 according to an embodiment.

The light emitting device 100 according to the embodiment includes a first conductivity-type semiconductor layer 112, an active layer 114 on the first conductivity-type semiconductor layer 112, and a second conductivity-type semiconductor on the active layer 114. Layer 116 may be included. The first conductivity type semiconductor layer 112, the active layer 114, and the second conductivity type semiconductor layer 116 may be referred to as a light emitting structure 110.

_{In the embodiment, an Al p} Ga _q In _1-pq N layer (0<p≤1, 0≤q≤1) 122 is formed between the active layer 114 and the second conductivity type semiconductor layer 116. It is provided to increase the luminous efficiency through the electron blocking function.

The embodiment may include a light-transmitting electrode 130 on the second conductivity-type semiconductor layer 116, and are electrically connected to the second conductivity-type semiconductor layer 116 and the first conductivity-type semiconductor layer 112, respectively. A second electrode 152 and a first electrode 151 may be included.

The embodiment may be a horizontal light emitting device in which the light emitting structure 110 is disposed on a substrate 102 as shown in FIG. 2, but is not limited thereto, and may also be applied to a vertical light emitting device.

3 is an energy bandgap diagram of a light emitting device according to an embodiment.

The embodiment is intended to provide a light emitting device capable of improving luminous intensity or electrical characteristics.

In the prior art, when an AlGaN layer is used as an electron blocking layer and a p-type AlGaN layer is used as a hole injection layer, Mg and PID ((Pyramidal Inversion Domain)) are stacked according to the Al composition in the p-type AlGaN layer compared to pGaN. The defects do not diffuse well to the surface of the p-type semiconductor layer after growth, and may gather at the interface between the AlGaN electron blocking layer and the p-type AlGaN layer.

When stacking defects are gathered at the interface, hole injection becomes difficult due to unsaturated defects, which are dangling bonds, and contact resistance increases, resulting in an increase in operating voltage (VF3) and a decrease in luminance (Po). Occurs.

In order to solve this problem, the light emitting device according to the embodiment includes the Al _p Ga _q In _{1 -p- q N layer (0<p} ≦1, 0≦q≦1) 122 and a second conductivity type semiconductor layer. An AlGaN-based super lattice layer 124 may be provided between 116.

For example, as shown in Figure 3, the AlGaN based superlattice layer 124 in the embodiment is sentenced soft Al _y Ga _{1 - y} N layer (where, 0 <y <1) ( 124a) and the p-type Al _x Ga _{1 - x} N layer (where, 0 <x <1) may include (124b).

According to an embodiment _{, an undoped Al between the Al p} Ga _q In _{1 -p- q N layer (however, 0<p} ≦1, 0≦q≦1) 122 and the second conductivity type semiconductor layer 116 _y Ga _{1 - y} N layer (however, 0<y<1) (124a) and p-type Al _x Ga _{1 - x} N layer (however, 0<x<1) (124b) The hole injection efficiency can be increased by uniformly spreading the stacking defects, such as Mg or PID, which are accumulated in, and current spreading can be improved by the 2DHG (2-dimensional hole gas) effect.

Specifically, the second of the undoped Al _y Ga _1-y N layer (however, 0<y<1) (124a) and the p-type Al _x Ga _1-x N layer (however, 0<x<1) (124b) The lattice layer can prevent agglomeration of stacking defects such as Mg or Pyramidal Inversion Domain (PID), which is a p-type doping element, or evenly spread the stacked stacking defects, through which Al _p Ga _q In _{1 -p- q} N The interface quality between the layer (however, 0<p≤1, 0≤q≤1) 122 and the second conductivity type semiconductor layer 116 is improved, thereby improving the hole injection efficiency. The luminous intensity Po and the operating voltage VF3 may be improved.

In addition, according to the embodiment, the AlGaN-based superlattice layer 124 includes an undoped Al _y Ga _1-y N layer (however, 0<y<1) 124a, and has a superlattice structure, so current due to carrier diffusion Since current spreading is effectively performed, internal luminous efficiency can be increased.

Embodiment the sentence prompt Al _y Ga ₁ in the example _{- y} N layer (where, 0 <y <1) ( 124a) and the p-type Al _x Ga _{1 - x} N layer (where, 0 <x <1) ( 124b) A pair of may be 1 to 5 pairs. The sentence prompt Al _y Ga _{1 -} a pair of _y N layer (where, 0 <y <1) ( 124a) and the p-type Al _x Ga _1-x N layer (where, 0 <x <1) ( 124b) is The presence of at least one or more can contribute to light intensity improvement and carrier diffusion, and if the number of pairs exceeds 5 pairs, a thick superlattice structure or thick undoped Al _y Ga _{1 - y} N layer (however, 0<y<1) Hole injection may be disadvantageous by the (124a) layer.

Embodiment the sentence prompt Al _y Ga ₁ in the example _{- y} N layer (where, 0 <y <1) ( 124a) or the p-type Al _x Ga _{1 - x} N layer (where, 0 <x <1) ( 124b) The thickness of may be about 1.5 nm to 3 nm. When the thickness of each layer is more than 3 nm, it may be disadvantageous for hole injection, and when the thickness of each layer is less than 1.5 nm, the effect of improving the quality of the interface may be small.

Above in Example sentence prompt Al _y Ga _{1 - y} N layer (where, 0 <y <1) ( 124a) The aluminum concentration (y) is the p-type Al _x Ga _1-x N layer (where, 0 <x of <1) It may be less than or equal to the aluminum concentration (x) of 124b. The sentence prompt Al _y Ga _{1 - y} N layer (where, 0 <y <1) the aluminum concentration (y) the type p Al _x Ga ₁ of (124a) _{- x} N layer (where, 0 <x <1) ( If it is greater than the aluminum concentration (x) of 124b), the effect of current spreading may be reduced.

For example, the prompt undoped Al _y Ga _{1 -} aluminum concentration (y) range of _y N layer (124a) may be 0.04≤y≤0.15.

The sentence prompt Al _y Ga _{1 -} if _y N is less than the aluminum concentration (y) is 0.04 of the layer (124a), the less a Mg or PID diffusion barrier (diffusion block) or the dispersing effect, by the light generated in the quantum well absorbed Light intensity reduction may occur. On the other hand, when the _{aluminum concentration (y) of the undoped Al y} Ga _1-y N layer 124a is greater than 0.15, the luminosity decreases due to a decrease in quality due to a high Al composition or a decrease in hole injection, and VF3 rise problems may occur.

The p-type Al _x Ga _{1 -} aluminum concentration (x) range of _x N layer (124b) may be 0.20≤x≤0.35.

When the aluminum concentration (x) of the p-type Al _x Ga _{1 - x} N layer 124b is less than 0.20, effects such as blocking diffusion of Mg or PID may be lowered. On the other hand, when the _{aluminum concentration (x) of the p-type Al x} Ga _1-x N layer 124b is greater than 0.34, the luminance decreases or the operating voltage (VF3) increases due to a decrease in hole injection due to a high Al composition or a decrease in crystal quality. Such problems may occur.

The embodiment may provide a light-emitting device capable of improving an interface quality of a light-emitting device, thereby improving a luminous intensity according to an increase in hole injection efficiency and an electrical characteristic according to an operation voltage VF3.

In addition, according to the embodiment, the internal luminous efficiency may be increased by improving the interface quality and increasing the carrier diffusion function.

Hereinafter, a method of manufacturing a light emitting device according to an embodiment will be described with reference to FIGS. 4 to 6.

First, a substrate 102 is prepared as shown in FIG. 4. The substrate 102 may be formed of a material having excellent thermal conductivity, and may be a conductive substrate or an insulating substrate.

For example, the substrate 102 is sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ 0 ₃ At least one of can be used. An uneven structure may be formed on the substrate 102, but the embodiment is not limited thereto.

In this case, a buffer layer (not shown) may be formed on the substrate 102. The buffer layer can alleviate lattice mismatch between the material of the light emitting structure 110 and the substrate 102 to be formed later, and the material of the buffer layer is a group 3-5 compound semiconductor such as GaN, InN, AlN, InGaN, AlGaN. , InAlGaN, it may be formed of at least one of AlInN.

Next, a light emitting structure 110 including a first conductivity type semiconductor layer 112, an active layer 114, and a second conductivity type semiconductor layer 116 may be formed on the first substrate 102.

The first conductivity type semiconductor layer 112 may be formed of a semiconductor compound. It may be implemented with a compound semiconductor such as Group 3-5 and Group 2-6, and may be doped with a first conductivity type dopant. When the first conductivity-type semiconductor layer 112 is an n-type semiconductor layer, the first conductivity-type dopant is an n-type dopant, and may include Si, Ge, Sn, Se, and Te, but is not limited thereto.

The first conductivity type semiconductor layer 112 may include _{a semiconductor material having a composition formula of In d} Al _e Ga _{1 -de} N (0≤d≤1, 0≤e≤1, 0≤d+e≤1). I can.

The first conductivity type semiconductor layer 112 may be formed of one or more of GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, AlGaAs, InGaAs, AlInGaAs, GaP, AlGaP, InGaP, AlInGaP, InP.

The active layer 114 may be formed of at least one of a single quantum well structure, a multi quantum well (MQW) structure, a quantum-wire structure, or a quantum dot structure. For example, in the active layer 114, trimethyl gallium gas (TMGa), ammonia gas (NH ₃ ), nitrogen gas (N ₂ ), and trimethyl indium gas (TMIn) may be injected to form a multiple quantum well structure. It is not limited thereto.

The active layer 114 may have a quantum well (114W)/quantum wall (114B) structure, for example, AlGaN/AlGaN, InGaN/GaN, InGaN/InGaN, GaN/AlGaN, InGaN/AlGaN, InAlGaN/GaN, GaAs /AlGaAs, InGaAs/AlGaAs, GaP/AlGaP, InGaP/AlGaP may be formed in any one or more pair structure, but is not limited thereto.

Next, the active layer 114, the _{Al p Ga q In 1 -p- q} N a layer (where, 0 <p≤1, 0≤q≤1) ( 122) than the energy band gap of the active layer 114 Since it is formed to have a high energy band gap, it serves as an electron blocking and an MQW cladding of an active layer, thereby improving luminous efficiency.

Next, an AlGaN-based superlattice layer 124 may be formed on _{the Al p} Ga _q In _{1 -p- q N layer (where 0<p≦1, 0≦q≦1) 122.}

Specifically, as shown in FIG. 3, in the embodiment, the AlGaN-based superlattice layer 124 is an undoped Al _y Ga _1-y N layer (however, 0<y<1) 124a and a p-type Al _x Ga _{1- It may include an x} N layer (however, 0<x<1) 124b.

According to an embodiment _{, an undoped Al y} Ga _{between the Al p} Ga _q In _1-pq N layer (however, 0<p≦1, 0≦q≦1) 122 and the second conductivity type semiconductor layer 116 _{The superlattice layer of 1-y} N layer (however, 0<y<1) (124a) and p-type Al _x Ga _1-x N layer (however, 0<x<1) (124b) is inserted into the interface. The hole injection efficiency can be increased by uniformly spreading the stacking defects such as Mg or PID, and current spreading can be improved by the 2-dimensional hole gas (2DHG) effect.

In the embodiment, the undoped Al _y Ga _1-y N layer (however, 0<y<1) (124a) and the p-type Al _x Ga _1-x N layer (however, 0<x<1) (124b) A pair of may be 1 to 5 pairs. The pair of the undoped Al _y Ga _1-y N layer (however, 0<y<1) (124a) and the p-type Al _x Ga _1-x N layer (however, 0<x<1) (124b) is The presence of at least one can contribute to light intensity improvement and carrier diffusion, and if the number of pairs exceeds 5 pairs, a thick superlattice structure or a thick undoped Al _y Ga _1-y N layer (however, 0<y<1) Hole injection may be disadvantageous by the (124a) layer.

In the embodiment, the undoped Al _y Ga _1-y N layer (however, 0<y<1) (124a) or the p-type Al _x Ga _1-x N layer (however, 0<x<1) (124b) The thickness of may be about 1.5 nm to 3 nm. When the thickness of each layer is more than 3 nm, it may be disadvantageous for hole injection, and when the thickness of each layer is less than 1.5 nm, the effect of improving the quality of the interface may be small.

In the embodiment _{, the aluminum concentration (y) of the undoped Al y} Ga _1-y N layer (however, 0<y<1) 124a is the p-type Al _x Ga _1-x N layer (however, 0<x <1) It may be less than or equal to the aluminum concentration (x) of 124b. The aluminum concentration (y) of the undoped Al _y Ga _1-y N layer (however, 0<y<1) 124a is a p-type Al _x Ga _1-x N layer (however, 0<x<1) ( If it is greater than the aluminum concentration x of 124b), the effect of current spreading may be reduced.

For example, the _{aluminum concentration (y) range of the undoped Al y} Ga _1-y N layer (however, 0<y<1) 124a may be 0.04≦y≦0.15. When the aluminum concentration (y) of the undoped Al _y Ga _1-y N layer (however, 0<y<1) 124a is less than 0.04, Mg or PID diffusion block or dispersion effect is reduced, Light generated from the quantum well may be absorbed, resulting in a decrease in light intensity. On the other hand, when the _{aluminum concentration (y) of the undoped Al y} Ga _1-y N layer (however, 0<y<1) 124a is greater than 0.15, the quality is lowered due to the high Al composition or hole injection ( Hole injection) may cause a decrease in brightness and increase in VF3.

The aluminum concentration (x) range of the p-type Al _x Ga _1-x N layer (however, 0<x<1) 124b may be 0.20≦x≦0.35. When the aluminum concentration (x) of the p-type Al _x Ga _1-x N layer (however, 0<x<1) 124b is less than 0.20, effects such as blocking diffusion of Mg or PID may be lowered. On the other hand, when the _{aluminum concentration (x) of the p-type Al x} Ga _1-x N layer (however, 0<x<1) (124b) is greater than 0.34, due to a decrease in hole injection or crystal quality due to a high Al composition Problems such as a decrease in luminous intensity or an increase in the operating voltage VF3 may occur.

Referring back to FIG. 4, a second conductivity type semiconductor layer 116 may be formed on the AlGaN-based superlattice layer 124.

The second conductivity type semiconductor layer 116 may include _{a semiconductor material having a composition formula of In d} Al _e Ga _1-de N (0≤d≤1, 0≤e≤1, 0≤d+e≤1). I can. When the second conductivity-type semiconductor layer 116 is a p-type semiconductor layer, the second conductivity-type dopant is a p-type dopant and may include Mg, Zn, Ca, Sr, Ba, or the like.

In an embodiment, the first conductivity-type semiconductor layer 112 may be implemented as an n-type semiconductor layer, and the second conductivity-type semiconductor layer 116 may be implemented as a p-type semiconductor layer, but is not limited thereto.

In addition, a semiconductor, for example, an n-type semiconductor layer (not shown) having a polarity opposite to that of the second conductivity type may be formed on the second conductivity type semiconductor layer 116. Accordingly, the light emitting structure 110 may be implemented in any one of an n-p junction structure, a p-n junction structure, an n-p-n junction structure, and a p-n-p junction structure.

Thereafter, a light-transmitting electrode 130 is formed on the second conductivity-type semiconductor layer 116.

For example, the light-transmitting electrode 130 may include an ohmic layer, and may be formed by laminating a single metal, a metal alloy, or a metal oxide in a single layer or multiple layers so that hole injection can be efficiently performed.

For example, the light-transmitting electrode 130 may include indium tin oxide (ITO), indium zinc oxide (IZO), indium zinc tin oxide (IZTO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), and IGTO. (indium gallium tin oxide), AZO (aluminum zinc oxide), ATO (antimony tin oxide), GZO (gallium zinc oxide), IZON (IZO Nitride), AGZO (Al-Ga ZnO), IGZO (In-Ga ZnO), ZnO, IrOx, RuOx, NiO, RuOx/ITO, Ni/IrOx/Au, and Ni/IrOx/Au/ITO, Ag, Ni, Cr, Ti, Al, Rh, Pd, Ir, Ru, Mg, Zn, Pt , Au, and may be formed including at least one of Hf, but is not limited to these materials.

Next, as shown in FIG. 5, the light-transmitting electrode 130, the second conductivity-type semiconductor layer 116, the AlGaN-based superlattice layer 124, and Al _p Ga _q In _{1 so that the first conductivity-type semiconductor layer 112 is exposed. The -p- q} N layer (however, 0<p≦1, 0≦q≦1) 122, and a part of the active layer 114 may be removed.

Next, as shown in FIG. 6, a second electrode 152 is formed on the light-transmitting electrode 130 and a first electrode 151 is formed on the exposed first conductivity-type semiconductor layer 112 to emit light according to the embodiment. Devices can be formed. The light-transmitting electrode 130 may have a through hole (not shown) formed in a partial area so that the second electrode 152 formed on the light-transmitting electrode 130 comes into contact with the second conductivity type semiconductor layer 116. It is not limited to this. In addition, an uneven shape (not shown) is formed on the upper surface of the light-transmitting electrode 130 to improve external extraction efficiency of light emitted from the active layer 114, but is not limited thereto.

The embodiment can provide a light emitting device capable of improving the luminous intensity according to the increase in hole injection efficiency and the electrical characteristics according to the improvement of the operating voltage (VF3) by improving the interface quality of the light emitting device, and a method of manufacturing the same. have.

In addition, according to the embodiment, the internal luminous efficiency may be increased by improving the interface quality and increasing the carrier diffusion function.

A plurality of light emitting devices according to the embodiment may be arrayed on a substrate in the form of a package, and an optical member, such as a light guide plate, a prism sheet, a diffusion sheet, and a fluorescent sheet, may be disposed on a path of light emitted from the light emitting device package.

For example, FIG. 7 is a diagram illustrating a light emitting device package in which a light emitting device is installed according to embodiments.

The light emitting device package according to the embodiment includes a package body part 205, a third electrode layer 213 and a fourth electrode layer 214 installed on the package body part 205, and the package body part 205. A light emitting device 100 electrically connected to the third electrode layer 213 and the fourth electrode layer 214, and a molding member 230 surrounding the light emitting device 100, and the molding member ( The phosphor 232 may be included in the 230).

The third electrode layer 213 and the fourth electrode layer 214 are electrically separated from each other and serve to provide power to the light emitting device 100. In addition, the third electrode layer 213 and the fourth electrode layer 214 may serve to increase light efficiency by reflecting light generated from the light emitting device 100, and It can also play a role in discharging heat to the outside.

The light emitting device 100 may be electrically connected to the third electrode layer 213 and/or the fourth electrode layer 214 by any one of a wire method, a flip chip method, or a die bonding method.

The light emitting device according to the embodiment may be applied to a backlight unit, a lighting unit, a display device, an indication device, a lamp, a street light, a vehicle lighting device, a vehicle display device, a smart watch, etc., but is not limited thereto.

For example, Figure 8 is an exploded perspective view of the lighting system according to the embodiment.

The lighting device according to the embodiment may include a cover 2100, a light source module 2200, a radiator 2400, a power supply unit 2600, an inner case 2700, and a socket 2800. In addition, the lighting device according to the embodiment may further include one or more of the member 2300 and the holder 2500. The light source module 2200 may include a light emitting device or a light emitting device package according to the embodiment.

The light source module 2200 may include a light source unit 2210, a connection plate 2230, and a connector 2250. The member 2300 is disposed on the upper surface of the radiator 2400 and has guide grooves 2310 into which a plurality of light source units 2210 and a connector 2250 are inserted.

The holder 2500 blocks the receiving groove 2719 of the insulating part 2710 of the inner case 2700. Accordingly, the power supply unit 2600 accommodated in the insulating unit 2710 of the inner case 2700 is sealed. The holder 2500 has a guide protrusion 2510.

The power supply part 2600 may include a protrusion 2610, a guide part 2630, a base 2650, and an extension part 2670. The inner case 2700 may include a molding unit together with the power supply unit 2600 therein. The molding portion is a portion in which the molding liquid is solidified, and allows the power supply unit 2600 to be fixed inside the inner case 2700.

Features, structures, effects, and the like described in the embodiments above are included in at least one embodiment, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, and the like illustrated in each embodiment may be combined or modified for other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Therefore, contents related to such combinations and modifications should be construed as being included in the scope of the embodiments.

Although the embodiments have been described above, these are only examples and are not intended to limit the embodiments, and those of ordinary skill in the field to which the embodiments belong to, without departing from the essential characteristics of the present embodiment, various not illustrated above. It will be seen that branch transformation and application are possible. For example, each component specifically shown in the embodiment can be modified and implemented. And differences related to these modifications and applications should be construed as being included in the scope of the embodiments set in the appended claims.

First conductivity type semiconductor layer 112, active layer 114,
In _p Ga _q Al _{1 -p- q} N layer (where, 0 <p≤1, 0≤q≤1) ( 122), AlGaN -based superlattice layer 124,
Undoped Al _y Ga _{1 - y} N layer (however, 0<y<1) (124a), p-type Al _x Ga _{1 - x} N layer (however, 0<x<1) (124b),
Second conductivity type semiconductor layer 116

Claims (7)

A first conductivity type semiconductor layer;
An active layer disposed on the first conductivity type semiconductor layer and including a plurality of quantum wells and quantum walls;
_{An Al p} Ga _q In _1-pq N layer disposed on the active layer (however, 0<p≦1, 0≦q≦1);
An AlGaN-based superlattice layer disposed on the Al _p Ga _q In _{1-pq N layer (where 0<p≦1, 0≦q≦1);} And
Including; a second conductivity type semiconductor layer disposed on the AlGaN-based super lattice layer,
The AlGaN-based superlattice layer includes an undoped Al _y Ga _1-y N layer (however, 0<y<1) and a p-type Al _x Ga _1-x N layer (however, 0<x<1),
A pair of the undoped Al _y Ga _1-y N layer (however, 0<y<1) and the p-type Al _x Ga _1-x N layer (however, 0<x<1) is from 1 pair to 5 pairs,
The aluminum concentration (y) range of the undoped Al _y Ga _1-y N layer (however, 0<y<1) is 0.04≤y≤0.15,
The aluminum concentration (x) range of the p-type Al _x Ga _1-x N layer (however, 0<x<1) is 0.20≤x≤0.35,
The energy band gap of the Al _p Ga _q In _1-pq N layer (however, 0<p≦ _{1, 0≦q≦1) is the undoped Al y} Ga _1-y N layer (however, 0<y<1). ) And greater than the energy band gap of the quantum walls of the active layer,
The energy band gap of the undoped Al _y Ga _1-y N layer (however, 0<y<1) is the energy band gap of the p-type Al _x Ga _1-x N layer (however, 0<x<1) A light emitting device that is smaller and larger than the energy band gap of the quantum walls of the active layer. The method of claim 1,
The Al _p Ga _q In _1-pq N layer (however, 0<p≤1, 0≤q≤1), the undoped Al _y Ga _1-y N layer (however, 0<y<1) and the p The energy band gap of the Al _x Ga _1-x N layer (where 0<x<1) is larger than the energy band gap of the second conductivity type semiconductor layer. The method of claim 1,
The undoped Al _y Ga _1-y N layer or the p-type Al _x Ga _1-x N layer has a thickness of 1.5 nm to 3 nm. delete delete delete A lighting system comprising a light-emitting unit comprising the light-emitting element according to any one of claims 1 to 3.

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