KR102181482B1 - 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 including a quantum well and a quantum wall on the first conductivity type semiconductor layer; A second conductivity type semiconductor layer on the active layer; And a first electrode and a second electrode electrically connected to the first conductivity type semiconductor layer and the second conductivity type semiconductor layer, respectively. The quantum well includes In _x Al _y Ga _(1-xy) N (however, 0<x<1, 0≤y<1), and the composition of indium in the quantum well includes a region in which the composition of indium gradually decreases, The composition of aluminum may include a gradually increasing area.

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.

Light Emitting Device is a pn junction diode that converts electrical energy into light energy. It can be created as a compound semiconductor such as Group III and Group V on the periodic table. Various colors can be realized by controlling the composition ratio of the compound semiconductor. It is possible.

When a 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 band gap energy of the conduction band and the balance band. Is mainly emitted in the form of heat or light, and becomes a light emitting device when radiated in the form of light.

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 band gap energy. In particular, a blue light-emitting device, a green light-emitting device, and an ultraviolet (UV) light-emitting device using a nitride semiconductor are commercialized and widely used.

1 is an exemplary diagram of an energy band diagram in a light emitting device according to the prior art.

According to the prior art, there is a problem in that the band structure is deformed (refer to area A) due to the internal field in the light emitting layer, and thus electrons and holes are spatially separated from each other, resulting in poor luminous efficiency.

The embodiment is to provide a light emitting device capable of increasing luminous efficiency, 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 112; An active layer 114 including a quantum well 114W and a quantum wall 114B on the first conductivity type semiconductor layer 112; A second conductivity type semiconductor layer 116 on the active layer 114; And a first electrode 151 and a second electrode 152 electrically connected to the first conductivity type semiconductor layer 112 and the second conductivity type semiconductor layer 116, respectively. The quantum well 114W contains In _x Al _y Ga _(1-xy) N (however, 0<x<1, 0≤y<1), and the composition of indium (In) in the quantum well 114W (x) includes a gradually decreasing area, and the composition (y) of aluminum (Al) may include a gradually increasing area.

In addition, the light emitting device according to the embodiment includes a first conductivity type semiconductor layer 112; An active layer 114 including a quantum well 114W and a quantum wall 114B on the first conductivity type semiconductor layer 112; A second conductivity type semiconductor layer 116 on the active layer 114; And a first electrode 151 and a second electrode 152 electrically connected to the first conductivity-type semiconductor layer 112 and the second conductivity-type semiconductor layer 116, respectively, wherein the quantum well 114W ), the slope of the energy level of the valence band and the conduction band may be different.

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

The embodiment can provide a light emitting device capable of increasing luminous efficiency, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system.

1 is an energy band diagram 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 band diagram of a light emitting device according to an embodiment.
4 is an energy band diagram and a composition distribution in a quantum well of a light emitting device according to an embodiment.
5 is luminous intensity comparison data of a light emitting device according to an embodiment and a comparative example.
6 is data comparing light-emitting recombination efficiency of a light-emitting device according to an embodiment and a comparative example.
7 to 9 are cross-sectional views illustrating a method of manufacturing a light emitting device according to an embodiment.
10 is a cross-sectional view of a light emitting device package according to an embodiment.
11 is an exploded perspective view of a lighting device according to an 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, standards 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 conductive type semiconductor layer 112 and an active layer 114 including a quantum well 114W and a quantum wall 114B on the first conductive type semiconductor layer 112. ), and a first electrode electrically connected to each of the second conductivity-type semiconductor layer 116 and the first conductivity-type semiconductor layer 112 and the second conductivity-type semiconductor layer 116 on the active layer 114 151 and a second electrode 152 may be included.

According to the embodiment, the luminous efficiency is increased by controlling the energy band structure of the active layer.

3 is an energy band diagram of a light emitting device according to an embodiment, and FIGS. 4(a) and 4(b) are compositions of indium (In) and aluminum (Al) in a quantum well of a light emitting device according to the embodiment, respectively It is a distribution diagram, and FIG. 4(c) is an exemplary diagram of an additional energy band diagram for region B of FIG. 3.

According to the embodiment, a lot of electrons and holes are distributed in the region C of FIG. 4(c), so that luminous efficiency can be improved.

In the prior art, there is an attempt to control the energy level by focusing on the change in the indium composition. However, in the case of making changes such as gradually decreasing the indium composition according to the prior art, the shape of the energy band is substantially controlled as in the embodiment. You cannot make electrons and holes gather on one side.

According to an embodiment, the method of making the energy band structure as shown in FIG. 3 or 4(c) is that the In composition gradually decreases when the quantum well 114W of the active layer 114 grows, and the Al composition gradually increases and then decreases again. Direction can grow.

For example, while gradually reducing the composition of indium in the quantum well 114W of the active layer as shown in FIG. 4(a), the composition of aluminum (Al) is gradually increased as shown in FIG. ), you can control the energy band.

In an embodiment, the quantum well 114W may include In _x Al _y Ga _(1-xy) N (however, 0<x<1, 0≤y<1), but is not limited thereto.

As shown in FIG. 4(a), in the quantum well 114W, the composition (x) of indium (In) includes a gradually decreasing area, and the composition (y) of aluminum (Al) is gradually increased. It may include.

The composition (x) of indium (In) in the quantum well 114W may be reduced from 20% to 8%.

In addition, the embodiment may include a region in which the composition of aluminum gradually increases and then gradually decreases, as shown in FIG. 4(b).

The composition of the aluminum may include a region gradually decreasing to 0% after increasing from 0% to 7%.

The reason why the Al composition is increased and then decreased again is that the wavelength may decrease when Al is added in an excessive amount, and thus the Al composition may be decreased after increasing the Al composition to a level at which energy bandgap control is achieved.

At this time, in the case of FIG. 3, the internal field of the active layer 114 is relaxed according to the application of the embodiment, so that the band gap energy level of the quantum well 114W is improved to a flat level.

Furthermore, according to an embodiment, the slope of the energy level of the valence band and the conduction band in the quantum well 114W as shown in FIG. 4(c) may be different.

For example, when the energy level slope C1 of the valence band in the quantum well 114W decreases, the slope C2 of the energy level of the conduction band may increase.

Through this, the bandgap energy as shown in Fig. 4(c) can be derived, and electrons and holes are collected in the left part of the quantum well 114W as in the C area, thereby maximizing the degree of coincidence of the probability distribution of electrons and holes to emit light. By increasing the recombination rate, the luminous efficiency can be increased.

On the other hand, the embodiment takes into account the difficulty of controlling the energy level of the valence band to be flat, and when the energy level of the conduction band is decreased by the technology device, it is controlled to rather increase the energy level of the valence band. With the left part (C area), you can make a band structure where electrons and holes can gather.

In an embodiment, in the case of the last well of the active layer 114, InGaN (not shown) may be inserted into the last barrier in order to improve the bending of the band.

5 is luminous intensity comparison data of a light emitting device according to an embodiment and a comparative example.

The luminous intensity (E) of the light emitting device according to the embodiment has an effect of remarkable improvement in luminous intensity of about 60 times or more compared to the luminous intensity (R1) of the comparative example.

6 is data for comparing light emission recombination efficiency between a light emitting device according to an embodiment and a comparative example.

The remarkable effect of improving light intensity as shown in FIG. 5 is because, as shown in FIG. 6, the light-emitting recombination efficiency (E) of the light emitting device according to the embodiment has a remarkable synergistic effect of about 100 or more compared to the light-emitting recombination efficiency (R1) of the comparative example. Was analyzed as.

According to the embodiment, the luminous efficiency can be remarkably increased by increasing the luminous recombination rate by maximizing the degree of correspondence between the probability distributions of electrons and holes in a quantum well.

Hereinafter, a method of manufacturing a light emitting device according to an exemplary embodiment will be described with reference to FIGS. 7 to 9.

First, a substrate 102 is prepared as shown in FIG. 7. 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 may use at least one of sapphire (Al ₂ O ₃ ), SiC, Si, GaAs, GaN, ZnO, GaP, InP, Ge, and Ga ₂ 0 ₃ . An uneven structure may be formed on the substrate 102, but the embodiment is not limited thereto.

Thereafter, 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.

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

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 is made of a semiconductor material having a composition formula of In _x Al _y Ga _{1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x+y≤1). Can include.

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 structure (MQW), 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 quantum well 114W/double barrier 114B of the active layer 114 is any one of InGaN/GaN, InGaN/InGaN, GaN/AlGaN, InAlGaN/GaN, GaAs(InGaAs)/AlGaAs, GaP(InGaP)/AlGaP It may be formed in the above pair structure, but is not limited thereto.

According to the embodiment, when the quantum well 114W of the active layer 114 is grown, the In composition gradually decreases, and the Al composition gradually increases and then decreases again.

For example, while gradually reducing the composition of indium in the quantum well 114W of the active layer as shown in FIG. 4(a), the composition of aluminum (Al) is gradually increased as shown in FIG. ), such as energy bands can be controlled.

In an embodiment, the quantum well 114W may include In _x Al _y Ga _(1-xy) N (however, 0<x<1, 0≤y<1), but is not limited thereto.

As shown in FIG. 4(a), in the quantum well 114W, the composition (x) of indium (In) includes a gradually decreasing area, and the composition (y) of aluminum (Al) is gradually increased. It may include. For example, the composition (x) of indium (In) in the quantum well 114W may be reduced from 20% to 8%.

In addition, the embodiment may include a region in which the composition of aluminum gradually increases and then gradually decreases, as shown in FIG. 4(b). For example, the composition of aluminum may include a region gradually decreasing to 0% after increasing from 0% to 7%.

In addition, according to the embodiment, the slope of the energy level of the valence band and the conduction band in the quantum well 114W as shown in FIG. 4(c) may be different.

For example, when the energy level slope C1 of the valence band in the quantum well 114W decreases, the slope C2 of the energy level of the conduction band may increase.

Through this, the bandgap energy as shown in Fig. 4(c) can be derived, and electrons and holes are collected in the left part of the quantum well 114W as in the C area, thereby maximizing the degree of coincidence of the probability distribution of electrons and holes to emit light. By increasing the recombination rate, the luminous efficiency can be increased.

The luminous intensity (E) of the light emitting device according to the embodiment has an effect of remarkable improvement in luminous intensity of about 60 times or more compared to the luminous intensity (R1) of the comparative example. This was analyzed because the light-emitting recombination efficiency (E) of the light emitting device according to the embodiment has a remarkable synergistic effect of about 100 or more compared to the light-emitting recombination efficiency (R1) of the comparative example.

According to the embodiment, the luminous efficiency can be remarkably increased by increasing the luminous recombination rate by maximizing the degree of correspondence between the probability distributions of electrons and holes in a quantum well.

Next, in an embodiment, an electron blocking layer 118 is formed on the active layer 114 to serve as electron blocking and MQW cladding of the active layer, thereby improving luminous efficiency. For example, the electron blocking layer 118 may be formed of an Al _x In _y Ga _(1-xy) N (0≦ _x ≦1,0≦ _y ≦1) based semiconductor, and the active layer 114 The energy band gap may be higher than that of the energy band gap, and may be formed to a thickness of about 100 Å to about 600 Å, but is not limited thereto.

Thereafter, the second conductivity type semiconductor layer 116 may be formed of a semiconductor compound. It may be implemented as a compound semiconductor such as Group 3-5 and Group 2-6, and may be doped with a second conductivity type dopant.

For example, the second conductivity type semiconductor layer 116 has a composition formula of In _x Al _y Ga _{1 -x- y} N (0≤x≤1, 0≤y≤1, 0≤x+y≤1) It may include a semiconductor material having. 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 stacking a single metal, a metal alloy, or a metal oxide in 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 to include at least one of Hf, but is not limited to these materials.

Next, as shown in FIG. 8, a part of the light-transmitting electrode 130, the second conductivity type semiconductor layer 116, the electron blocking layer 118, and the active layer 114 so that the first conductivity type semiconductor layer 112 is exposed. Can be removed.

Next, as shown in FIG. 9, a second electrode 152 is formed on the light-transmitting electrode 130 and a first electrode 151 is formed on the exposed first conductive semiconductor layer 112 to emit light according to the embodiment. Device can be formed.

The embodiment can provide a light emitting device capable of increasing luminous efficiency, a method of manufacturing a light emitting device, a light emitting device package, and a lighting system.

10 is a diagram illustrating a light emitting device package 200 in which a light emitting device is installed according to embodiments.

The light emitting device package according to the embodiment is installed on the package body portion 205, the third electrode layer 213 and the fourth electrode layer 214 installed on the package body portion 205, and the package body portion 205 A light emitting device 100 electrically connected to the third and fourth electrode layers 213 and 214, and a molding member 230 surrounding the light emitting device 100 are included.

The package body part 205 may be formed of a silicon material, a synthetic resin material, or a metal material, and an inclined surface may be formed around the light emitting device 100.

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 element 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 the horizontal type light emitting device illustrated in FIG. 2, but is not limited thereto, and a vertical light emitting device may also be applied.

The light emitting device 100 may be installed on the package body part 205 or on the third electrode layer 213 or the fourth electrode layer 214.

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. In the embodiment, the third electrode layer 213 and the fourth electrode layer 214 are electrically connected to each other through a wire, but the embodiment is not limited thereto.

The molding member 230 may surround the light-emitting device 100 to protect the light-emitting device 100. In addition, the molding member 230 may include a phosphor 232 to change a wavelength of light emitted from the light emitting device 100.

A plurality of light emitting devices or light emitting device packages according to the embodiment may be arrayed on a substrate, and an optical member such as a lens, a light guide plate, a prism sheet, and a diffusion sheet may be disposed on an optical path of the light emitting device package. Such a light emitting device package, a substrate, and an optical member may function as a light unit. The light unit may be implemented in a top view or a side view type, and may be provided to display devices such as portable terminals and notebook computers, or may be variously applied to lighting devices and indication devices. Another embodiment may be implemented as a lighting device including the light emitting device or the light emitting device package described in the above-described embodiments. For example, the lighting device may include a lamp, a street light, an electric sign, and a headlamp.

11 is an exploded perspective view of a lighting device according to an embodiment.

Referring to FIG. 11, the lighting device according to the embodiment includes a cover 2100, a light source module 2200, a radiator 2400, a power supply unit 2600, an inner case 2700, and a socket 2800. I can. In addition, the lighting device according to the embodiment may further include one or more of a member 2300 and a holder 2500. The light source module 2200 may include a light emitting device package according to the embodiment.

For example, the cover 2100 may have a shape of a bulb or a hemisphere, and may be provided in a shape with a hollow and an open portion. The cover 2100 may be optically coupled to the light source module 2200. For example, the cover 2100 may diffuse, scatter, or excite light provided from the light source module 2200. The cover 2100 may be a kind of optical member. The cover 2100 may be coupled to the radiator 2400. The cover 2100 may have a coupling portion coupled to the radiator 2400.

A milky white paint may be coated on the inner surface of the cover 2100. The milky white paint may include a diffuser that diffuses light. The surface roughness of the inner surface of the cover 2100 may be larger than the surface roughness of the outer surface of the cover 2100. This is to allow light from the light source module 2200 to be sufficiently scattered and diffused to be emitted to the outside.

The material of the cover 2100 may be glass, plastic, polypropylene (PP), polyethylene (PE), polycarbonate (PC), or the like. Here, polycarbonate is excellent in light resistance, heat resistance, and strength. The cover 2100 may be transparent or opaque so that the light source module 2200 is visible from the outside. The cover 2100 may be formed through blow molding.

The light source module 2200 may be disposed on one surface of the radiator 2400. Accordingly, heat from the light source module 2200 is conducted to the radiator 2400. 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 an 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 guide groove 2310 corresponds to the substrate and the connector 2250 of the light source unit 2210.

The surface of the member 2300 may be coated or coated with a light reflective material. For example, the surface of the member 2300 may be coated or coated with a white paint. The member 2300 reflects light reflected on the inner surface of the cover 2100 and returning toward the light source module 2200 toward the cover 2100. Therefore, it is possible to improve the light efficiency of the lighting device according to the embodiment.

The member 2300 may be made of an insulating material, for example. The connection plate 2230 of the light source module 2200 may include an electrically conductive material. Accordingly, electrical contact may be made between the radiator 2400 and the connection plate 2230. The member 2300 may be formed of an insulating material to block an electrical short between the connection plate 2230 and the radiator 2400. The radiator 2400 receives heat from the light source module 2200 and heat from the power supply unit 2600 to radiate heat.

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 guide protrusion 2510 has a hole through which the protrusion 2610 of the power supply unit 2600 passes.

The power supply unit 2600 processes or converts an electrical signal provided from the outside and provides it to the light source module 2200. The power supply unit 2600 is accommodated in the storage groove 2719 of the inner case 2700 and is sealed inside the inner case 2700 by the holder 2500.

The power supply unit 2600 may include a protrusion 2610, a guide portion 2630, a base 2650, and an extension 2670.

The guide portion 2630 has a shape protruding outward from one side of the base 2650. The guide part 2630 may be inserted into the holder 2500. A number of components may be disposed on one surface of the base 2650. A number of components include, for example, a DC converter that converts AC power provided from an external power source to DC power, a driving chip that controls driving of the light source module 2200, and an ESD for protecting the light source module 2200 (ElectroStatic discharge) may include a protection element, but is not limited thereto.

The extension part 2670 has a shape protruding outward from the other side of the base 2650. The extension part 2670 is inserted into the connection part 2750 of the inner case 2700 and receives an electrical signal from the outside. For example, the extension part 2670 may be provided equal to or smaller than the width of the connection part 2750 of the inner case 2700. Each end of the "+ wire" and "- wire" may be electrically connected to the extension part 2670, and the other end of the "+ wire" and "- wire" may be electrically connected to the socket 2800. .

The inner case 2700 may include a molding unit together with the power supply unit 2600 therein. The molding part is a part where the molding liquid is solidified, and allows the power supply part 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 can be implemented by combining or modifying 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 interpreted 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 are not departing from the essential characteristics of the embodiments. 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, quantum well 114W, quantum wall 114B,
Active layer 114, second conductivity type semiconductor layer 116, first electrode 151, second electrode

Claims (11)

A first conductivity type semiconductor layer;
An active layer including a quantum well and a quantum wall on the first conductivity type semiconductor layer;
A second conductivity type semiconductor layer on the active layer; And
And a first electrode and a second electrode electrically connected to the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer, respectively,
The quantum well includes In _x Al _y Ga _(1-xy) N (however, 0<x<1, 0≤y<1),
In the quantum well, the composition of indium includes a gradually decreasing area, and the composition of aluminum includes a gradually increasing area,
A light emitting device in which the composition of indium in the quantum well is reduced from 20% to 8%. delete A first conductivity type semiconductor layer;
An active layer including a quantum well and a quantum wall on the first conductivity type semiconductor layer;
A second conductivity type semiconductor layer on the active layer; And
And a first electrode and a second electrode electrically connected to the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer, respectively,
The quantum well includes In _x Al _y Ga _(1-xy) N (however, 0<x<1, 0≤y<1),
In the quantum well, the composition of indium includes a gradually decreasing area, and the composition of aluminum includes a gradually increasing area,
A light emitting device including a region in which the composition of the aluminum gradually increases and then gradually decreases. The method of claim 1 or 3,
The composition of the aluminum is
A light emitting device including a region gradually decreasing from 7% to 0% after increasing from 0% to 7%. A first conductivity type semiconductor layer;
An active layer including a quantum well and a quantum wall on the first conductivity type semiconductor layer;
A second conductivity type semiconductor layer on the active layer; And
And a first electrode and a second electrode electrically connected to the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer, respectively,
The slope of the energy level of the valence band and the conduction band in the quantum well is different,
The quantum well includes In _x Al _y Ga _(1-xy) N (however, 0<x<1, 0≤y<1),
In the quantum well, the composition of indium includes a gradually decreasing area, and the composition of aluminum includes a gradually increasing area,
A light emitting device in which the composition of indium in the quantum well is reduced from 20% to 8%. The method of claim 5,
When the energy level slope of the valence band in the quantum well decreases, the energy level slope of the conduction band increases. delete delete A first conductivity type semiconductor layer;
An active layer including a quantum well and a quantum wall on the first conductivity type semiconductor layer;
A second conductivity type semiconductor layer on the active layer; And
And a first electrode and a second electrode electrically connected to the first conductivity-type semiconductor layer and the second conductivity-type semiconductor layer, respectively,
The slope of the energy level of the valence band and the conduction band in the quantum well is different,
The quantum well includes In _x Al _y Ga _(1-xy) N (however, 0<x<1, 0≤y<1),
In the quantum well, the composition of indium includes a gradually decreasing area, and the composition of aluminum includes a gradually increasing area,
A light emitting device including a region in which the composition of the aluminum gradually increases and then gradually decreases. The method of claim 5 or 9,
The composition of the aluminum is
A light emitting device including a region gradually decreasing to 0% after increasing from 0% to 7%. An illumination system comprising a light-emitting unit comprising the light-emitting element according to any one of claims 1, 3, 5 and 9.

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